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Патент USA US3039648

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June 19, 1962
3,039,638
w. M. SHAFFER
NARROW-AISLE LIFT TRUCK
Filed March 9, 1961
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Filed March 9, 1961
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NARROW-AISLE LIFT TRUCK
Filed March 9, 1961
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June 19, 1962
w. M. SHAFFER
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NARROW-AISLE LIFT TRUCK
Filed March 9, 1961
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June 19, 1962
W.‘M. SHAFFER
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NARROW-AISLE LIFT TRUCK
Filed March 9, 1961
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June 19, 1962
3,039,638
w. M. SHAFFER
NARROW~AISLE LIFT TRUCK
Filed March 9, 1961
'7 Sheets-Sheet 6
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United States
Patented June 19, 1962
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3,039,638
the lift truck is provided with a conventional steering
wheel for the operator and the steering linkage is con
Walter M. Shaffer, Cleveland, Ohio, assignor to Tow
nected to the dirigible wheels for normal steering of the
vehicle with the lifting forks forwardly of the vehicle
NARROW-AISLE LIFT TRUCK
motor Corporation, Cleveland, Ohio, a corporation of
Ohio
Filed Mar. 9, 1961, Ser. No. 94,531
15 Claims. (Q1. 214-730)
This invention relates to lift trucks and more particu—
larly to a narrow aisle lift truck characterized by a drive
axle assembly including a mast and fork which may be
4)
3,039,638
" " atent
and the drive axle transversely of the vehicle and wherein
linkage is provided which operatively connects the out
riggers to the dirigible wheels so as to maintain the
dirigible wheel at one side of the vehicle in alignment with
an outrigger wheel at the opposite side of the vehicle.
It is ‘a further object of my invention to provide a
lift truck according to the preceding object wherein the
turned from a position transversely of the lift truck to
outriggers when swung to storage position in said space
a position aligned with the central axis of the lift truck
at each side of the vehicle, the outer free ends of said
to facilitate stacking of loads in a narrow aisle. Lift
Outriggers are in engagement with means carried by the
trucks of this type permit the use of narrow aisles: and 15 drive axle so that the drive axle may not be turned from
result in allowing more than 35% more material being
its position transversely of the vehicle when the out
put into a warehouse.
riggers are both in storage position.
This invention relates to lift trucks of the type shown
It is a further object of my invention to provide a lift
and ‘described in my co-pending application “Narrow
truck according to the preceding objects wherein swing
Aisle Warehousing Lift Truck,” Serial No. 698,663, ?led
ing of one outrigger from its storage position to an ex
November 25, 1957, now Patent No. 2,986,295, (Docket
tended position disengages said outrigger with respect to
No, 10-458) of which the instant application is a con
the drive axle so that the drive axle may be turned through
tinuation-in-part and the hyd-aulic drive of the instant
the space on the same side of the vehicle as said extended
application is also characterized by components corre
outrigger, but is prevented from being swung in an op
sponding to those disclosed and claimed in my co-pend 25 posite direction by the ‘other outrigger which is main
ing application “Hydraulic Drive for Lift Truck,” Serial
No. 849,588, ?led October 29, 1959 (Docket No. 5908)
tained in storage position.
of which the instant application is a continuation-in-part.
It is among the objects of the instant invention to pro
lift truck according to the preceding objects wherein the
It is a further object of my invention to provide a
lift truck is provided with a power unit such as an in
vide a lift truck having a frame which is characterized by 30 ternal combustion engine having an ignition circuit where
a relatively wide rear portion which supports the power
in the outriggers and the front drive axle are operatively
unit and wherein the rear portion of the frame is sup
arranged with respect to switches in said ignition circuit
ported by dirigible wheels and the forward part of the
so that the operation of the power unit is interrupted upon
frame is characterized by an elongated narrow central
movement of the axle and Outriggers toward an unsafe
portion which has pivoted at its outer end a transverse 35 position so that a safety interlock is provided between the
drive axle. The mast and lifting ‘fork assembly is car-v
ried by the front drive axle and means are pro
power unit and the manipulation of the drive axle and
Outriggers.
vided to swing the drive axle from its normal po
sition transversely of the frame to a position wherein
It is a further object of my invention to provide a hy
draulic drive mechanism for a lift truck according to the
the drive axle is aligned with the central axis running 40 preceding objects wherein the power unit is arranged to
longitudinally of the frame. This arrangement results
drive a pair of gear pumps and wherein the output of
in the lifting forks and the load carried thereby to be
the gear pumps is characterized by the one pump being
at right angles to the lift truck. To provide stability
about twice the capacity of the other pump and wherein
for such sharp turning and to guide the lift truck as loads
a tilt-hoist valve is provided for tilting the mast and rais
are being stacked by the lift truck, Outriggers are arranged 45 ing and lowering the carriage or lifting-forks and wherein
so that when extended they are aligned with one of the
dirigible wheels.
One of the results of the construction provided is that
a drive control valve is provided for determining the drive
condition of the vehicle, and wherein hydraulic cylinder
means are provided for swinging the outriggers and where
when an outrigger is swung to one side of the lift truck,
in variable displacement hydraulic motors are provided
it raises that side of the lift truck so as to raise the 50 to drive the traction wheels of the vehicle and a multi
dirigible wheel nearest the extended outrigger away from
the ?oor and, at the same time, the dirigible wheel at
the opposite side of the lift truck is aligned with the
phase valve is provided for guiding the vehicle for stack?
ing operations.
Further objects and advantages relating to economies
in manufacture, e?iciency and safety in operation, rugged
of the lift truck is greatly increased and stability against 55 ness of construction and ease of operation and service
overturning due to the eccentric position of the load is
will appear from the following description and the ap
wheel on the extended outrigger so that the eifective width
provided.
It is among the objects of my invention to provide a
lift truck as described in the preceding paragraphs where
pended drawings wherein:
FIG. 1 is a perspective view of a lift truck made accord
ing to my invention;
in the mounting of the drive axle on the narrow frame 60
FIG. 2 is a plan view with parts in section showing the
extension provides a space at each side of the lift truck
linkage between the dirigible wheels, the outriggers and
and wherein the outriggers may be swung into this space
the drive axle;
for storage when the drive axle is transversely of the
FIG. 3 is an elevation with parts in section taken as
vehicle. When an outrigger is extended at the left-hand
indicated by the plane 3—3 of FIG. 2;
side of the vehicle, then the drive axle may be turned 65
FIG. 4 is an elevation with parts in section taken as
so as to swing into this space at the left-hand side of
indicated by the plane 4——4 of FIG. 2;
the vehicle. Conversely, when the right-hand outrigger
FIG. 5 is an end elevation of the dirigible wheel mount
is extended, the drive axle may be turned so as to move
ing taken as indicated by the plane 5—~5 of FIG. 2;
through the right-hand space vacated by the right-hand
FIG. 6 is a view taken from the rear of the lift truck
70 with ‘the right-hand outrigger extended so as to tilt the
outrigger.
It is a further object of my invention to provide a lift
vehicle slightly and raise the right-hand dirigible wheel
truck according to the two preceding objects wherein
from the floor or supporting surface;
e,ose,eee
FIG. 7 is a plan view showing the lift truck diagram
matically with the right outrigger extended and the lift
ing forks swung to the right-hand side of the vehicle;
FIG. 8 is a view similar to FIG. 7 showing the left-hand
outrigger extended and the forks turned to the left-hand
side of the vehicle;
‘FIG. 9 is a plan view and wiring diagram showing the
interlock between the drive axle, the Outriggers and the
Li
provision of the narrow forward portion 7 of the frame
results in a space being provided at each side of the lift
truck and a left-‘hand outrigger 27 is arranged to swing
into the left-hand space indicated at 28. Similarly right
hand outrigger 29 is arranged to be swung into the space
indicated at 36.
The front axle assembly 25 is provided with a U-shaped
frame indicated at 31 which is turned with the drive axle
when the drive axle is swung to the position shown in
FIG. 10 is a view showing the hydraulic system for tilt 10 FIGS. 7 and 8. The frame member 31 includes a later
ignition circuit for the power unit;
ing the mast, hoisting the carriage, swinging the outrig
ally projecting lug 32 which projects into the space 30.
The right-hand outrigger 29 is provided with an out
rigger wheel 33 and the outer end of the wheel axle 33a
is provided with a lug 34 having a stud 34a which en
gages the lug 32 on the frame 31. This arrangement,
15
in conventional forward or reverse drive;
as best show-n in FIG. 2 and FIG. 4, prevents the drive
FIG. 12 is a sectional View of the multi-phase valve
axle from turning about the pivot ‘9 to the right since
showing the control plunger of the valve as moved to a
the lugs 32 and 34:: are in engagement. The left-hand
position for rotating the front axle of the vehicle by rotat
side of the vehicle includes a similar arrangement wherein
ing the drive wheels in opposite directions;
gers and providing traction for the vehicle;
FIG. 11 is a sectional view of the multi-phase valve
showing the position of the valve parts with the lift truck
FIG. 13 is a sectional view of the multi-phase valve
showing the position of the valve‘ plunger for guiding the
drive wheels in a stacking operation by rotating the drive
wheels in the same direction but at different rates of
a lug 36 carried by frame 31 extends into the space 28
alongside of the traction wheel 16 and there engages a
stud 37 carried by member 38 on the axle 3541 of the
left-hand outrigger wheel 35.
Accordingly it will be
understood that when the vehicle is in normal forward
rotation;
FIG. 14 is a sectional view of the displacement valve 25 drive ooeration and the Outriggers are retracted, as shown
in FIGS. 1 and 2, the drive axle assembly cannot be
for determing the displacement of the drive motors un
turned to either side of its normal forward drive position.
der different modes of operation of the vehicle; and
The right-hand outrigger 27 is pivotally mounted by
FIG. 15 is a sectional view of a pilot-operated check
pivot pin 49‘ carried in the bracket 41 secured to the
valve forming a part of the hydraulic operation and con
30 transverse frame member 42. The inclination of the
trol of the outrigger cylinders.
pivot pin 40 causes the outer free end of the outrigger
Referring to the drawings, the lift truck frame is in
to be raised to the position shown in FIGS. 1 and 4 with
dicated in its entirety as at 6. The rear portion of the
the wheel 35 elevated with respect to the supporting
frame 6 is considerably wider than the narrow elongated
surface 43. According, when the outrigger 27 is swung
forward portion indicated at 7. The frame portion 7 is
arched centrally thereof as shown in FIG. 1 to provide 35 into the storage space 28 at the side of the vehicle, it is
elevated with respect to the sup-porting surface for the
clearance for the traction wheels. Preferably side frame
vehicle. Conversely, when the outrigger 29 is swung to
members 8 taper toward the front of the vehicle and termi
an extended position, as shown in FIGS. 6 and 7, the
nate in an integrally formed elongated arched neck por
outrigger wheel is brought into engagement with the
tion 7 which provides a journal support for a vertical
pivot 9 connecting the drive axle assembly to the frame. 40 ‘supporting surface and, as it is brought into engagement
with the supporting surface, it is effective to raise that
The rear portion of the frame preferably includes a
side of the vehicle having an extended outrigger. The
counterweight indicated at '10 and a motor housing 11
raising or tilting of the vehicle by the outrigger is effec
with the operator’s seat indicated at :12 above a part of
tive to raise the adjacent dirigible wheel away from the
the motor housing. A protective canopy structure indi
45 supporting surface.
cated at '13 extends laterally over the operator.
In FIG. 6 the right-hand outrigger wheel 33 has been
The drive axle assembly includes a right-hand trac
fully extended by outrigger arm 29 which is effective to
tion wheel 15 and a left-hand traction wheel 16-. Beneath
raise the dirigible wheel 17 from the supporting surface
the rear portion of the frame the right-hand dirigible
and bring the axis of the outrigger wheel 33 into align
wheel 17 is mounted on a spindle 65 and a left-hand dirigi
ment with the axis of the dirigible wheel 18. FIG. 7 is
ble wheel ‘18 is similarly mounted on spindle 67. Lifting
a plan view corresponding to the elevation of FIG. 6‘ and
forks 19 and 20 are carried by the carriage 21 which is
as here shown the axis of the outrigger wheel 33 and the
arranged to slide vertically on the mast assembly 22.
axis of the dirigible wheel 18 ‘are coincident on the line
The mast assembly is provided with a hoist cylinder 23
indicated at 45. Operation of the drive wheels 15 and
and chains 24 attached to the carriage to raise and lower
the carriage and move the mast sections relative to each 55 16 in the same phase of forward rotation brings the load
on the forks into stack S in the aisle A. The reduction
other. The mast assembly and the load carriage and lift
in aisle width results in more e?icient use of the ware
ing forks are carried on the front drive axle assembly
house floor space. Thus when the outrigger 29‘ is ex
which is indicated in its entirety as at 25.
tended, the effective width of the vehicle corresponds to
By means hereinafter described in detail, the ‘lift truck
is adapted to be operated with the forks forwardly of the 60 the distance between the outrigger wheel 33 and the
dirigible wheel 18. This provides for stability adjacent
lift truck as illustrated in ‘FIG. 1 and this is referred to
the load carried by the lifting forks at the right-hand
herein as the normal forward operation of the vehicle.
side of the vehicle. Conversely, swinging of the left
When it is desired to manipulate the truck in a narrow
hand outrigger 27 and its wheel 35 brings the outrigger
aisle, such as would be found in a warehouse, and to
handle pallets for stacking with the lift truck, the drive 65 wheel 35 into alignment with the dirigible wheel 17 along
axle 25 is adapted to be turned so as to be in line with
the axis indicated at 46 in FIG. 8.
This means that
the central axis through the vehicle indicated as at 26
in FIGS. 7 and 8. As will be described hereinafter in de
dirigible wheel 18 is lifted from the floor by the tilting
of the vehicle and stability is provided for the load on
opposite the direction of the other traction motor and thus
turn the drive axle assembly 25 to the position shown in
The cylinder 47 is pivotally carried by the frame bracket
48 and the piston rod 49‘ extending from the cylinder 47
FIGS. 7nd 8.
cylinders for the outriggers are double-acting cylinders
the forks at the left-hand side of the vehicle.
tail, the drive axle is provided with a pair of hydraulic
The hydraulic means ‘for swinging the outriggers in
traction motors which are controlled by the operator so 70
cludes the hydraulic cylinders at each side of the vehicle.
that one traction motor may be operated in a direction
It will be observed ‘from FIGS. 1, 2, 7 and 8 that the
is pivoted to the outrigger 27 as at 50.
The hydraulic
$3,039,638
6
and when hydraulic ?uid is introduced into the cylinder
‘at one side of the piston, the piston rod is projected
effective to turn the dirigible wheels into alignment with
therefrom to extend the outrigger as heretofore de
scribed. Upon directing ?uid to the other side of the
the outrigger wheels.
In accordance with the foregoing description of the
piston, the outrigger is retracted.
At the right-hand side of the vehicle, hydraulic cylin
der 51 is provided which is carried by ‘frame bracket 52
mechanical interlock between the Outriggers and the drive
and the piston rod 53 is pivoted to the outrigger 29 as
at 54. It will be understood that the valves for the hy
ever, the outriggers are extended, the links 88 and 96 are
axle, the outriggers prevent turning of the drive axle rela
tively to the vehicle when the Outriggers are in stored posi
tion. Extending one outrigger will permit the rotation of
the drive axle with respect to the frame about the pivot
draulic ?uid admitted to the cylinders 47 and 51 are ac 10 9 in a direction toward the extended outrigger.
cessible to the operator as illustrated in FIG. 1. A lever
In the interests of safety, means are provided to pre
55 controls the valve directing ?uid into the left-hand
vent the extension of both Outriggers at the same time
outrigger 2.7 and control lever 56 directs the ?uid into
and to limit the rotation of the drive axle with respect to
the right-hand outrigger 51.
Each lever and the valve
the frame to the proper positioning of the Outriggers.
Preferably an electrical interlock arrangement is provided
outrigger," “neutral” and “retract outrigger.”
as shown diagrammatically in FIG. 9‘. As heretofore
A steering Wheel 57 is operatively connected to a
described, the hydraulic pumps for moving the various
steering wheel shaft 58 and thence through steering re
hydraulic components and providing traction are driven
duction gear 59 to steering arm 60 connected to the
by the engine indicated at 150.
steering link 61. The rear end of the link 61 is opera 20
The engine 150 includes an ignition system which
tively connected to the depending ball 62 carried by the
derives its electrical power from the storage battery 19/1.
steering ‘axle assembly 63. The assembly 63 includes a
The negative side of the battery is preferably grounded
king pin unit 64 for the right-hand dirigible wheel spindle
to the vehicle frame as at 102 and the engine is also
65. A ‘left-hand king pin unit 66 carried by the assembly
grounded to the frame as at 103'. The positive side of the
63 and left-hand wheel spindle 67 is carried on the king
battery leads, by way of line 104, to line 105 connected
pin unit 66.
to one side of a normally open switch 106. The other
A steering yoke assembly is pivoted on the dirigible
side of the switch 106 has connected thereto the line
wheel frame as at 68. The yoke assembly includes an
107 leading to junction 108. A line 109 leads from the
controlled thereby has three positions, namely, “extend
upper transverse arm 69 having a left-hand depending
junction 108 to one side of a normally open switch 110'.
ball 70 and a right-hand depending ball 71. The yoke
assembly includes the sleeve portion 72 which connects
The term “normally open switc ,” as used herein, means
that the switch includes a button as at 111 which is biased
outwardly of the switch box and, when moved to its pro
the upper arm 69 to the lower ‘arm 73 for joint swinging
movement. A tie link 74 connects the ball 75 on the
jected position by a spring within the switch box, the cir
swinging yoke 73 to the ball 76 for the left-hand spindle
cuit is broken within the switch. When, however, the
67. Similarly the ball 78 carried at the upper side of 35 button 111 is depressed, the circuit is completed through
the switch.
the yoke "73 is connected by the tie bar 79 to the ball 80
carried by spindle 65. When the operator turns the
The switch 106 includes a button 112 which is depressed
steering wheel 57, the movement of link 61 is trans
to close the circuit through the switch by means of the
mitted to the yoke assembly including upper and lower
cam 113 integrally formed on the member 31 carried by
arm 69 and 73, respectively, and the motion of the yoke
the drive axle and pivoted with respect to the vertical
pivot 9.
members is transmitted to the spindles 65-67 for steering
the vehicle for normal forward drive.
It will be understood that in the event the drive axle
To turn the dirigible wheels into proper position for
and the member 311 is turned about the pivot 9 in either
alignment with the selected outrigger, a linkage arrange
direction, the button 112 will be projected and the cir
ment is provided connecting each outrigger to the diri 45 cuit ‘opened in the switch 106.
The hand-operated lever 55 controlling the left-hand
gible wheel assembly and steering mechanism. A bracket
outrigger 27 and the lever 56 controlling the right-hand
82 is carried by the frame adjacent the left-hand out
outrigger 29 are arranged with respect to the button 111
rigger pivot 40 and the bracket provides a pivotal mount
so that movement of either lever to the dotted line “re
ing as at ‘83 for the triangular plate 84. A link 85 has
one end thereof pivoted as at 86 to the outrigger 27 and 50 tract outrigger” position will open the circuit through the
switch 110; Switches 106 and 110 are arranged to pre
the other end thereof pivoted as at $7 to the plate 84.
A link 88 is pivoted as at 39 on the triangular plate 84
and extends rearwardly therefrom within a tube 90' which
vent retraction of an outrigger with the front end as
sembly in a rotated position.
A normally open switch 115' is mounted on the frame
is pivotally mounted on the ball 70‘ depending from the
55 of the lift truck so as to be engaged by the inner edge
upper yoke 69 of the steering mechanism.
of the outrigger 27 when the outrigger is moved to re
The link 88 is provided with an enlarged head portion
tracted or storage position as shown in FIG. 9. Similar
91 sliding within the tube 90 and accordingly when the _
ly, a normally open switch 116 is mounted on the lift
yoke 69 is rocked by the normal steering operations of
truck frame adjacent the outrigger 29 and the circuit
the vehicle in forward drive, the tube 90 will slide to and
fro with respect to the rod 88 which remains stationary 60 through the switch 116 is maintained as long as the out
rigger is held in its retracted position. A line 117 leads
in space. When, however, the outrigger 27 is extended
from the junction lit-8 to the junction 118 on line 119
laterally of the vehicle, the head 9'1 abuts the shoulder
extending between terminals on the switches 115 and
at the end ‘of the tube as at 92, thus rocking the yoke 69
116. A line 120 leads from the switch 115‘ through the
and turning the dirigible wheels to bring the right-hand
dirigible wheel into alignment with the axis of the left 65 juncture 121 and thence to line 122 for the ignition sys
tem 123.
hand outrigger Wheel.
In FIG. 9 the Outriggers and the drive axle are shown
A similar interconnection is provided between outrigger
in the position occupied for normal forward drive of the
29 by means of bracket 9-3, plate 94- ‘and links 95v and
vehicle. Assuming that the operator has moved the ve
96 moving with respect to the tube 97 connected to the
right-hand ball 71 on the yoke 69. It Will be understood 70 hicle into a position for stacking a load, the right-hand
outrigger lever 56 may be moved to the dotted line posi
that the arrangement is such that for normal forward drive
tion shown which will result in the swinging of the out
of the vehicle, as illustrated in FIG.-1, the dirigible
rigger 29 to an extended position. The current for the
wheel spindles 65 and 67 are moved freely by the opera
ignition system is conducted through line 104, thence
tor’s manipulation of the steering wheel 57 and such mo.
tion will have no effect on the Outriggers. When, how 75 through line 105 through switch 106, line 107, to junc
3,039,638
tion 108', thence through line 117 through junction 118,.
thence through line 119, switch 115, line 120‘, junction
121 and line 122 to the ignition system 123. This means
that the engine continues to operate and provide hydraulic
8
are driven by the power unit 150. The large pump is
indicated at 151 and the small pump at 152. Preferably
the gear pump 151 has a capacity of about twice the
gear pump 152. A reservoir 153 for hydraulic ?uid
is connected by 'line 154 to the input side of the large
power for the tilt and hoist cylinders and for the traction
pump 151 and by line 155 to the input side of the small
at the drive axle. With the outrigger 29‘ extended and
pump 152. The output of the large pump is directed
the lever 56 moved to the neutral position shown in full
through line 156 to port 157 of the tilt-hoist valve 158.
lines, the button 111 is again depressed, maintaining a
The tilt-hoist valve is preferably of the construction
circuit through the switch 110‘.
It will be noted that when the lever 56 was moved 10 disclosed in my co-pending application Serial No. 849,
588 which was ?led October 29, 1959 (Docket No.
out of its neutral position to the “retract outrigger” posi
5908). The tilt-hoist valve includes one manually mov
tion, the button 111 was released and the circuit was
able plunger 159 which directs hydraulic ?uid by way
broken through the switch 110. Now the drive axle
of line 160 to the hoist cylinder 23.
motors may be operated so as to turn the drive wheels
in opposite directions and thus swing the drive axle 15 As will be understood by reference to FIG. 1 of the
drawings, the cylinder 23 raises and lowers the load
assembly 25 about the pivot 9 in a clockwise direction as
along the mast 22 of the lift truck. A second manually
viewed in FIG. 9.
operable plunger for the tilt-hoist valve 158 is indicated
The movement of the drive axle and the member 31
at 161 and movement of this plunger is effective to di
carried thereby with respect to the pivot 9' releases the
button \112 and causes the switch 186 to move to open 20 rect hydraulic ?uid through line 162 to the tilt cylinder
163 or, alternatively, to line 164 to the other end of the
position. The power circuit to the engine ignition system,
tilt cylinder 16-3. It will be understood that the tilt cyl
however, is now maintained through line 104, through
inder 163 is a double-acting cylinder and is connected
line 185a, thence through the switch 118 to line 109 to
to the tiltable mast 22 of the lift truck so as to tilt the
the junction 168 and thence to the ignition system 123
25 mast with the load carriage thereon.
as above described.
A line 165 leads from port 166 on the tilt-hoist valve
It will be understood that manipulation of the left-hand
body to a port 167 on the vehicle drive control valve
outrigger 27 will open the switch at 115- and that the cir
168. The vehicle drive ‘control valve 168 is preferably
cuit to the engine would be completed through the switch
of the type disclosed in detail in my said co-pending ap
116, providing the outrigger '29 is in storage position.
It will be observed, however, that in the event the opera 30 plication Serial No. 849,588, filed October 29, 1959
(Docket No. 5908). In FIG. 10 two views of the ve
tor should attempt to swing the outrigger 27 to extended
hicle control valve 168 are shown. The lower view of
position when the outrigger 29‘ is extended, both switches
the valve 168 illustrates side 1 of the valve showing the
1,15 and 116 Awould be open and the circuit to the ignition
conduit connections between side 1 of the vehicle con
system 123 would be broken. Accordingly the engine
would stop and there would be no source of hydraulic 35 trol valve 168 and the multi-phase valve 170. The up
permost view of the vehicle control valve 168 illustrates
?uid power and the truck could not be manipulated into
side 2 of the valve body and shows a conduit leading
an unsafe or unstable position. This is a safety feature
to the drive motors and a conduit leading to the multi
that would prevent the extension of both Outriggers ‘at the
phase valve 170. The two views of the vehicle drive
same time.
The electrical interlocking system provided also pre
vents the retraction of an outrigger with the drive axle
turned so as to position the drive wheels along the cen
tral axis of the vehicle. Assuming that the outrigger
29 is extended, as above described, and the drive axle
assembly is turned 90° from the position shown in FIG.
9 so as to permit operation of the lift truck for stacking,
the normal ‘manipulation would call for rotating the
control valve 168 are enclosed within a phantom outline
168a.
For purposes of clearly illustrating the control units
for the hydraulic system, the multi-phase valve 170 is
also illustrated so as to show two sides of the valve 170.
Side 2 of the multi-phase valve 170 is at the rightehand
of the phantom line enclosure 170a. This side 2 shows
the conduit connections to the vehicle drive control
valve 168 and the left-hand showing of the multi-phase
drive axle so as to be transverse of the vehicle before
valve 170 illustrates the connections between the multi
the outrigger 29 is retracted. As above pointed out,
the circuit to the ignition system, when the drive axle 50 phase valve and the drive motors. The left-hand drive
motor is illustrated at 171 and the rightahand drive
is turned 90° from the position shown, is through the
motor at 172.
switch @110. The switch ‘106 has been opened by the
As will be understood from the instant description
turning movement of the cam 113 relative to the switch
and from the disclosure of my co-pending application
106. Now, if the operator should inadvertently attempt
to retract outrigger 29 by moving the lever 56, he would 55 Serial No. 698,663, ?led November 25, 1957 (Docket
No. 10458), for normal forward or reverse move
open the switch 11!) and thus stop the engine and in
ment of the vehicle the two drive motors 171 and 172
operate in the same phase so as to drive the vehicle
either forward or in reverse. When the vehicle is
ated when it is recognized that when the drive axle is
turned from a position transversely of the vehicle to a 60 operated for stacking, as described in connection with
FIGS. 6, 7 and 8, the drive motors 171 and 172 are
position with the drive wheels aligned with the central
in opposite phase and during opposite phase opera
axis of the vehicle, the "load on the forks is eccentric of
tion one drive wheel 15 is rotated in one direction and
the vehicle and should be supported by the extended out
the other drive wheel ‘16 is rotated in an opposite di
rigger. The safety provision of the electrical interlock
between the drive axle and the Outriggers insures that 65 rection. According to the instant invention the two
drive motors 171 and .172 may be operated and guided
the load on the lifting forks will always be supported
so as to vary the rotation of the drive wheels relative
and stabilized by an extended outrigger.
to each other and thus establish a control for the drive
The hydraulic system for the vehicle as illustrated
wheels which will‘ guide the vehicle accurately through
in FIG. 10 includes the power unit 150. It will be un
derstood that the hydraulic system of the instant inven 70 a range of motion which could not be achieved inthe
absence of the multi-phase valve control. With the
tion is suited for drive by an electric motor and that
multiphase valve both motors 171 and 172 may be
when thus driven the electrical resistance units usually
turned in the same direction but at different rates. In
employed to vary the speed of drive of the different com
the instant invention the conduits for the hydraulic sys
ponents in an electrical truck may be eliminaed.
Two hydraulic pumps, preferably of the gear type, 75 tem and the structure of the valves therefor is such
terrupt the hydraulic ?uid power supply.
The importance of this safety feature will be appreci
9
8,039,638
that it is possible to put the motors in
dis
placement without regard to the torque demand on
the drive wheels.
The movement of the control plunger 173 of the
vehicle drive control valve 168 is preferably deter
mined by manual movement of a foot pedal conven
iently accessible to the operator as in my said co-pend
ing application Serial No. 849,588. The manual con
trol of the multi-phase valve 170 is preferably effected
10
pressure line 191 is connected at side port ‘192 on the
motor 172 and the line 191 terminates at port 193 of
the multi-phase valve 170. When the drive control valve
168 is moved to a position so as to direct the ?ow of
?uid through line 188 in the direction of the arrow 194,
the spent hydraulic ?uid coming from the motor 172 by
way of line 191 moves in the direction of the arrow 195
back to the multi-phase valve 170. From the multi
phase valve 170 the spent ?uid is returned through line
by moving the plunger 174 through linkage connected 10 210 to the drive control valve, thence through line 222,
to the hand lever 175 on the steering post which lever
is convenient for the operator of the vehicle. It is
?lter 223 and line 224 to the reservoir.
When, however,
the drive control valve is moved to a reverse position,
understood that notches or latches common to the art
may be arranged on the ‘steering post so as to hold the
hydraulic ?uid under pressure moves from the multi—
phase valve through line 191 in the direction of arrow
hand lever 175 in either of the three distinct phases 15 196. Such hydraulic ?uid after driving the motor 172
of operation of the multi-phase valve 170. It will also
returns the spent ?uid to the multi-phase valve 178
be understood that the hand lever ‘175 and the plunger
through line ‘188 in the direction of the arrow 197.
174 are suited for manual controlling movements be
A similar hydraulic connection is established between
tween each of the three distinct positions of the multi
the drive control valve 168, the multi-phase valve 170
phase valve.
20 and the drive motor 171. Line 198 is connected to the
The output from the small pump 152 is directed by way
motor 171 at port 199 and said line 198 terminates at
of conduit 176 to port 177 on the outrigger control valve
port 280 in the multi-phase valve 170. The other hy
178. The outrigger control valve 178 is operated by
draulic line for motor 171 is the line 201 which is con
means of the levers 55 and 56 convenient to the left hand
nected to the motor 171 at center boss 202 and termi
of the operator. The plungers 55a and 56a are mov 25 nates in the multi-phase valve at port 203.
able so ‘as to individually control the movements of the
It will be understood that when hydraulic ?uid is di
outrigger cylinders 47 and 51. The structure of the out
rected from the multi-phase valve to the motor 172 in the
rigger control valve 178 is preferably of the type such
as disclosed in my said co-pending application Serial No.
direction of arrow 194, hydraulic ?uid is also directed by
way of line 201 to the motor 171 in the direction of
849,588.
arrow 284. Under such circumstances both motors 171
and 172 are in the same phase and are turning in the
'It will ‘be observed that the output from the small pump
152 is conducted in the ?rst instance to the outrigger
control valve 5178 and thus the carry-over from that out
put is thereafter directed from the valve ‘178 by way of
line 215 to the drive control valve 168, unless diverted 35
same direction. During such phase the hydraulic ?uid
from the motor is returning to the multi-phase valve in
the direction of the arrow 285 along line 198. Both
motors may be driven in an opposite direction and in the
same phase by reversing the direction of the ?uid ?ow
to the outrigger cylinders 57 and 51 by operation of either
plunger 55a or 56a. The output from the large pump 151
to the multi-phase valve 170 as determined by the ve
is connected in the ?rst instance to the tilt-hoist valve 158
hicle drive control valve 168. Thus the operator directs
and unless diverted to the hoist cylinder 23 or the tilt
the vehicle in a forward or reverse direction by the foot
cylinder 163, the volume from pump 151 is also directed 40 pedal position re?ected in the plunger 173 of the ve
to the vehicle drive control valve 168. This arrange
hicle drive control valve.
ment provides that the outrigger cylinders 51 and 47
A pair of conduits connect the drive control valve 168
may be operated coincident with the lifting of a load
to the multi-phase valve 170. One line 207 is connected
on the hoist cylinder 23.
to port 288 on the drive control valve 1168 and terminates
The drive motors 171 and 172 are variable displace 45 at port 209 of the multi-phase valve 170. The other
ment motors such as the motors disclosed in my said co
line 210 is connected to the valve 168 at port 211. The
pending applications Serial No. 698,663 and Serial No.
line 210 terminates in the multi-phase valve at port
849,588. The displacement of the drive motors is con
212.
trolled by tilting a wobble plate (not shown in the in
stant application) and such tilting is effected by pressure
responsive means, such as a piston and cylinder (not
shown). The control ?uid pressure is directed through
line 179 leading to the motor 172 and line 180 leading
Assuming the plunger 173 is moved to a forward drive
position by the foot pedal of the operator. Fluid ?ow
from the pumps to the valve 168 is then directed in the
direction of the arrow 213 into the multi-phase valve
170 and such ?uid, after being utilized to drive the
to the motor 171. Said two lines are connected to a
motors 171 and 172, returns to the drive control valve
line 181 which terminates at port 182 in the vehicle 55 168 along line 210 in the direction of the arrow 214.
drive control valve 168.
Reversing the position of the plunger 173 will reverse
it will be understood that by varying the pressure in
the ?uid ?ow in the lines 287 and 210‘ so that the motors
the line 181, the displacement position of the wobble
171 and 172 are operated in the same phase to drive the
plate, and hence the displacement of the motors 171
vehicle in reverse.
and 172, is varied. Leakage within the housing of the 60
The line 215 is connected to the outrigger control valve
pump 172 is drained through line 183 and thence by
at port 220 and the line 215 terminates in the drive con
line 184 to the reservoir 153. Similarly a drain line
trol valve 168 at port 217. The output from the small
185 conducts the leakage from motor 171 to the line
pump 152 when not required to move the Outriggers is
184 and thence to the reservoir 153. Fluid is also re
carried over by way of line 215 to the vehicle drive con
turned to the reservoir 153 by way of line 186 connected 65 trol valve. Accordingly, in the event there is no move
to port 187 on the tilt-hoist valve. A return ?uid line 220
ment of the hoist cylinder 23 or the tilt cylinder 163
leads from the outrigger control valve 178 to the reser
or the outrigger cylinders 47 and 51, the output of both
voir 153.
motors is directed into the valve body 168. When the
As will be understood from said co—pending applica
vehicle is operated at high speed, the output of both
tions, the direction of drive on the driving motors 171 and 70 pumps 151 and 152 is available for driving the motors 171
172 is determined by the direction of ?uid ?ow through
and 172.
the lines connecting the motors ‘171 and 172 to the multi
A conduit 225 leads from port 225a of the outrigger
phase valve 170. A line 188 is connected to the center
control valve through pilot operated check valve 226 and
boss 189 on the motor ‘172 and the line 188 terminates
thence through line 227 to one end of the double-acting
at port 190 on the multi-phase valve 178. A second ?uid 75 hydraulic cylinder 51. The cylinder 51 is arranged as
3,039,638
11
above described to move the right-hand‘ outrigger to and
from retracted position. Movement of the outrigger con
trol valve plunger 56a directs ?uid under pressure to the
right-hand end of cylinder 51 and the piston within the
cylinder is thereupon moved so as to extend the piston
rod 228 from the cylinder 51.
The ?uid within the cylinder at the left side of the
piston is moved out of the cylinder by way of line 229,
thence through check valve 226 and line 2311 which tenni
nates at port 231 of the outrigger control valve. The
pilot operated check valve 226 is constructed and ar
ranged so as to hydraulically lock the piston rod 228 in
12
ing from the multi-phase valve 170 to the vehicle drive
control valve 168.
When it is desired to rotate the drive axle by placing
the motors in opposite directional rotation, the multi
phase valve 170 is moved to the position illustrated in
FIG, 12. This is accomplished by moving the valve
plunger 174 inwardly as indicated at position B of FIG.
12. Hydraulic ?uid under pressure enters the multi
phase valve 170 through the conduit 207 and ?lls the
space 250. Such ?uid is directed out of the space 250 by
way of port 251, line 201 to the motor 171 which is
driven in the same directional rotation as illustrated in
FIG. 11. The spent ?uid leaves the motor by way of
line 198 and thence into space 253 by way of port 252.
The plunger 174 is provided with an elongated land
hydraulic lines leading to the left-hand outrigger cylin 15
which terminates in a shoulder at 262. A space is pro
der 47.
vided at 263 between the end of the shoulder and the
In FIG. 15 I have illustrated the check valve 226 and
edge of the port 264 whereby ?uid from the space 253
it will be understood that the check valve 232 is con
is directed to ?ow into space 258. The narrow land 266
structed and arranged like the check valve 226. Re—
on the plunger has closed the port 267 so that the hy
ferring to FIG. 15, the line 225 leads into a bore 233 in
draulic ?uid from the space 253 may not escape into
the body of the check valve 226. When fluid is directed
chamber 251;‘. Accordingly, hydraulic ?uid in the space
into line 225, thence through the bore 233 in the direction
258 is discharged through the port 257 into conduit 191
of the arrow 234, the ball check 235 is raised from its
to motor 172 so as to drive the motor 172 in a direction
seat by the ?uid pressure and the ?uid exits from the
valve body by way of line 227. The valve body 226 is 25 opposite the direction of drive illustrated in FIG. 11. The
?uid from motor 172 is conducted by way of line 188
provided with a transverse bore 236 which terminates in
into space 255 by way of ‘the port 256. The movement
a pilot cylinder 237 and the ?uid pressure thus transmitted
of the plunger 174 from the position A of FIG. 11 to the
acts against the piston 238 to raise the check valve 239
position of FIG. 12 uncovers a transverse bore 268 in the
from its seat and permit flow through passageway 2411 in
land 269. Thus ?uid in the space 255 may escape from
the direction of the arrow 241. A similar arrangement
the space 255 through the transverse bore 268 into the
is provided by way of transverse passage 242 and piston
either its retracted or extended position. A similar pilot
operated hydraulic check valve 232 is arranged in the
243 so as to open the check valve 235 in the event ?uid
is introduced in the direction of the arrow 244 for a
retracting movement of the outrigger.
It will be understood that in the event the outrigger is
being retracted, ?uid within the cylinder 51 returns to
the outrigger control valve 178 in the direction of the
arrow 245. It will be understood that in the absence of
movement of hydraulic ?uid in either direction, the ball
check valves 235 and 239 hold the Outriggers in locked
position. This provides a hydraulic lock for the out
riggeis and insures against the Outriggers drifting away
from retracted or extended position in the absence of
manual manipulation of the plungers 56a and 55a.
A line 246 leads from the outrigger control valve 178
through the pilot operated check valve 232, thence through
line 247 to one end of the left-hand outrigger cylinder 47.
A second ?uid line 248 leads from the outrigger control
longitudinal chamber 27 0 formed centrally of the plunger
174. The ?uid received within the chamber 270 then
exits through another transverse bore 271 formed in the
land 272. Thus the ?uid from the motors is discharged
from the transverse bore 271 into the space 259 and exits
through the passageway 273 into conduit 210 leading
from the multi-phase valve 170 to the drive control valve
168.
The transverse bore 271 which terminates in the land
272 is provided with a milled groove 275. The groove
275 in the land 272 provides a metering groove to obtain
accurate control of the hydraulic ?uid permitted to by
pass one or the other motor.
When the lift truck is arranged as illustrated in FIG.
7 with the outrigger 29 extended and the drive axle turned
at right angles to the vehicle with respect to the stack
indicated at S, it is important that both drive wheels turn
valve 178 through check valve 232, thence through line
249 to the other end of the outrigger cylinder. The de
tailed description of pilot operated check valve 226 is
applicable to the check valve 232.
The multi-phase valve 171} is illustrated in detail in
FIGS. 11, 12 and 13. In FIG. 11 the multi-phase valve
at the same speed and in the same direction so that the
pressure for driving the motor 172 moves from space 251}
then turn in unison in the same direction to continue the
forks 19 and 211 will go straight into the stack indicated
at S. During such operation the drive motors should
not be aifected by differences in load which might be
caused by bumps in the floor. The term “guidance” as
used herein is for guiding the drive wheels and fork as
sembly into the stack in the event the operator does not
is in a neutral or normal position for conventional for
have the truck stopped in the aisle with the drive wheels
ward drive of the vehicle. The left-hand motor 171 and
accurately lined up with the stack. The operator, by
the right-hand motor 172 are being driven in the same
manipulating the lever 175 on the steering column, may
direction for normal drive of the vehicle with the out
move the plunger 174 of the valve 170 within certain
riggers retracted. During such normal drive the vehicle
is steered by the steering wheel 57. Conduit 2117 con 60 limits here described and thus e?ect variations in rota
tion of one drive wheel relative to the other and thus,
ducting hydraulic ?uid under pressure from the drive
in effect, hydraulically steer the drive wheels and the
control valve leads such ?uid into the annular chamber
forks 19 and 2t) accurately into the stack. Once the
250. Such ?uid under pressure moves out of the space
operator has, by moving the plunger 174, guided the
250 in the multi-phase valve 170‘ through port 251, con
duit 201 and through the motor 171. The spent ?uid re 65 drive wheels and the forks 19 and 20 accurately into
alignment with the stack, the plunger is restored to the
turns from the motor 171 through line 193 and port 252
position indicated at C in FIG. 13 and the drive wheels
into the space 253 within the valve body. The ?uid under
through the port 254, thence into space 255, out port 256
motion of the forks into the stacking position. With the
through line 138 to the motor 172. The spent ?uid from 70 plunger 174 in the position indicated at C in FIG. 13,
the spaces formed by the cavities in the valve body 170
the motor 172 leaves the motor by way of line 191 and
and the lands on the plunger 174 are arranged so that the
discharges by way of port 257 into space 253. The spent
motors are in full series circuit with all of the ?uid going
?uid from both motors, that is, the ?uid in space 253 and
through each motor and thus the drive wheels must turn
the ?uid in space 258, is moved into space 259. A port
at the same speed and they are not aifected by the loads
‘260 in the space 259 discharges into a conduit 210v lead
13
3,039,638
which may be imposed on the drive wheels individually
by bumps in the ?oor.
The inward guidance range of the drive wheels is
indicated by the space C to C1 in FIG. 13 and the out
ward guidance range is indicated by the space between C
and C11 in FIG. 13.
As will be understood, the path of ?uid ?ow through
14
thus when the vehicle is backed away from the stack,
the guiding is to the left. The rate of guiding, that is,
the difference between the revolutions per minute of the
two drive wheels, even though in the same phase, is thus
accurately controlled by the operator with the lever 175
mounted on the steering column.
As will be understood from reference to my said co—
the multi-phase valve 170, as shown in FIG. 13, is ?rst
pending application Serial No. 849,588, ?led October 29,
by way of line 207 into the space 250, thence through
1959, (Docket No. 5908), the vehicle control valve in
port 251 and line 201 to the hydraulic motor 171. The 10 cludes a displacement valve which operates to control the
‘?uid ?ow from the motor 171 is by way of line 198,
displacement of the drive motors in accordance with the
thence into space 253 by way of the port 252 into space
torque demand at the drive wheels of the vehicle. The
279, thence axially of the valve body into space 255 to
lift truck of the instant application also includes a dis
the port 256 which leads to the motor 172 by way of
placement control valve 300 which is mounted on, or
line 188. Fluid from the motor 1'72 thence travels by 15 forms a part of the drive control valve 168. For clarity
way of line 191 to port 257 which terminates in space
and explanation, the displacement control valve 300 in
258. From space 258 the ?uid moves axially into space
the instant case is disclosed within the phantom outline
259 and thence from the displacement valve body 170 by
168a.
way of port 260, passage 273 and line 210 leading to the
The displacement control valve 300, during the conven
drive control valve 168.
20 tional drive of the lift truck, operates in response to the
With the plunger 174 of the valve 170 arranged in full
torque demand at the drive wheels to place the hydraulic
line position as indicated by position C in FIG. 13,
drive motors in position of displacement corresponding
and thereafter moved further to the left toward the po
to the torque requirement substantially as described in
sition indicated at position C1, the transverse bore 268
detail in my co-pending application Serial No. 849,588
in the land 269 opens into the space 250 by reason of 25 (Docket No. 5908). In the displacement valve 300 of
the counterbore forming the shoulder at 278. Coincident
the instant application, however, a line from the displace
with this movement of the plunger 174 toward position
ment valve leads to the multi-phase valve 170 so that
C1, the milled groove 275 opens into space 253 by rea
when the multi-phase valve is operated in either of the
son of the shoulder 279a. Under this circumstance a
phases shown in FIGS. 12 or 13, the displacement valve
limited amount of hydraulic ?uid may move from space 30 300 will be operated to place the motors in maximum
250 into the transverse bore 268 and thence through the
displacement position.
central bore 270 and through milled groove 275 into
Referring to FIG. 14, the valve body, indicated in its
space 253.
entirety as at 300, is provided with an inlet 167a which
The limited amount of ?uid which is permitted to
comes from a high pressure area in the drive control valve.
move through this path thus by-passes the left-hand mo 35 It will be noted from the hydraulic diagram of FIG. 10
tor 171 but is directed into the right-hand motor 172.
that the output of the large pump 151 leads through the
The ?uid thus metered into space 253 moves into space
tilt-hoist valve 158 and thence to a port 167 in the vehicle
255 and thence into the right-hand motor 172 by way
control valve 168. The high pressure line 167a leads
of conduit 188. The ?uid from the right-hand motor
from this high pressure area in the control valve 168 to the
172 moves through conduit 191 and port 257 into space 40 transverse passageway 303 in the displacement valve 300.
258. Such ?uid from space 258 is conducted out of the
A chamber 307 is provided within the valve body 300
multi-phase valve 170 by way of passageway 273 and
which is in communication with the inlet 303. A bore,
space 259. The discharge from 273 is conducted by
located beneath the chamber 387, receives the spring
way of conduit 210 to the drive control valve 168. The
pressed plunger 304. Located at the right side of the
left-hand motor 171 accordingly rotates slower than the 45 valve body is a conduit 181 which leads by way of
right-hand motor 172 since a part of the ?uid normally
branches 179 and 188 to the drive motor control. It
directed to the left-hand motor is by-passed to the right
will be understood that when high ?uid pressure leaves
hand motor. In this way accurate guidance toward the
the displacement valve by line 181, it moves the wobble
left of the two drive wheels is accomplished while mov
plate in the drive motors to the position of maximum dis
ing the forks and front drive axle into stacking position. 50 placement. Lower pressures in line 181 reduce the dis
It will be understood by the preceding description that
placement. At the top of the displacement valve 300 is a
a reversing of the plunger 173 in the drive control valve
line 167b which connects a space 167a within the dis
168 will reverse the direction of ?ow through the multi
placement valve to a relief ?ow sensing means within the
phase valve so that guidance is provided for the drive
drive control valve 168.
wheels when the vehicle is reversed as, for example, in
Reference is made to my said co-pending application,
moving a load out of a stack.
Serial No. 849,588, which illustrates and describes in de
Referring again to FIG. 13, and assuming that the
tail the drive control valve which is provided with a relief
plunger is pulled outwardly from the position C as indi~
?ow sensing means. The relief ?ow means of the drive
cated in full lines to a position indicated at C11. The re
sult of the plunger movement toward position C1 opens
the transverse bore 268 to the space 255 by reason of
the undercut indicated at 280. The second transverse
bore, namely, 271, opens into space 259 by reason of
the undercut 281. The amount of hydraulic ?uid which
control valve 168 in the instant case is similarly con
structed and includes a restricted flow passage between
the high pressure and low pressure areas within the drive
control valve 168. The said copending application, Serial
No. 849,588, also includes a detailed description and
showing of a displacement valve and the operative rela
moves from space 255 through the transverse bore 268 65 tionships between the displacement valve and the relief
into the longitudinal bore 270 and thence through trans
?ow sensing means in the drive control valve 168. A
verse bore 271 and metering groove 275 is by-passed
generally similar displacement control valve 300v is pro
into the discharge passageway 273 rather than being di
vided in the instant system and includes modi?cations for
rected to the right-hand motor 172. Accordingly, the
?uid conduit connections to the multi-phase valve 170 of
right-hand motor 172 rotates slower than the left-hand 70 the instant application.
motor 171 by the amount of the ?uid which is by-passed.
Referring to FIGS. 10 and 14 of the drawings, ?uid
Accordingly, the front end of the vehicle is then guided
conduit lines 167a, 301, 167i) and 181 are shown as es
toward the right as it is vbeing driven forward. As in the
establishing the hydraulic connections between the multi
situation previously described for guiding the vehicle to
phase valve 170, the drive motors 171 and 172 and the
the left, the vehicle control valve may be reversed and 75 relief ?ow sensing means forming a part of the drive
3,039,638
15
16
example, a quick reversal of the position of the plunger
chamber 15 on the sensing valve plunger 314 and thence
into the line 181 and thence to the motors tending to
move the displacement control in the motor to a posi
173 of the drive control valve 168 when the lift truck is
going at full speed, would result in the drive motors 171
and 172 functioning as pumps since they would be driven
In the event the sensing valve plunger 314 is moved
downwardly against the bias of its spring 317, the an
control valve 168. It will be understood that under cer
tain conditions of operation of the vehicle such as, for
tion of greater displacement.
nular chamber 315 will then open into the lower trans
verse bore 316a and thus line 181 may drain by way
driven ‘as pumps due to the vreversal of the plunger 173,
of the annular chamber 315, thence into transverse bore
they would (in the absence of protective means) demand
and outwardly by way of line 3111. In this way a
a ?uid supply approximately three times the maximum 10 316::
second ?ow path is established within the valve body 301}
volume (maximum total pump output) as when they are
between line 301 and line 181.
performing normally as motors. Due to the lack of such
In the event the multi-phase valve 170 is moved to the
?uid supply, the motors acting as pumps would cavitate
positions of FIGS. 12 and 13, the check valve system with
as pumps by the momentum of the vehicle. When thus
and might be damaged.
in the multi-phase valve is effective to introduce high ?uid
In the device of FIG. 14 of the instant application the 15 pressure into the displacement valve 300 by way of line
plunger 314 arranged in the bore at the right-hand side
301. In that event the flow sensing valve plunger 314
of FIG. v14 performs the function of a relief ?ow sensing
is moved upwardly to the position shown in full lines in
valve which responds to the relief ?ow sensing means
FIG. 14 and the plunger 304 is also moved upwardly so
in valve 168 and protects the motors under the conditions
that the upper end thereof abuts the bottom of the plug
described above. The ?uid pressure coming into the valve 20 310. High ?uid pressure then moves upwardly along
body 31111 by way of line 1671) would be relatively high
the groove 311 formed at the lower end of the plunger
under relief flow conditions and such higher pressure
304 and into the annular space 306 and thence laterally
would be e?ective to move the plunger 314 downwardly as
through passageway 316 into the annular chamber 315
viewed in FIG. 14.
on the plunger 314 and outwardly of the valve body 300
As will be understood from the preceding description,
into the line 181. Thus the drive motors 171 and 172
the line 181 leading to the displacement control for the
are placed in the position of maximum displacement by
motors places the motors in different positions of displace
reason of the high ?uid pressure introduced into the dis
ment in response to different ?uid pressures transmitted to
placement valve body 3110 from the multi-phase valve
the motors by way of line 181.
171} by Way of line 3111.
Under conditions of normal forward drive of the lift
With the multi-phase valve in the position shown in
truck, that is, with the drive axle transversely of the vehi
FIG. 11, that is, the position for conventional drive of
cle, the line 301 coming from the displacement valve body
the vehicle, the low pressure drainage ?uid from the dis—
300 serves as a drain line and thus the chambers 312 and
placement control valve enters the multi-phase valve by
313 at the lower portion of the valve body 300 (as viewed 35 Way of conduits 3111, thence through passageway 350 and
in FIG. 14) may be drained by way of passage through
bore 351 into an annular space 352 on the cup 353
the multi-phase valve. Under other conditions of vehi
integrally formed with the plunger 174. Openings 354
cle operation, that is, with the multiphase valve moved to
lead from the annular space 352 into the space 355.
the position shown in FIGS. 12 and 13, high ?uid pressure
Fluid escapes from the multi-phase valve 170 by way of
is brought into the chambers 312 and 313 in the valve 40 passage 356 connected to conduit 221 which leads to the
body 301) by way of the line 3111. Accordingly, the dual
low pressure space in the drive control valve 168. Ac
functions of the line 301 are determined by the phase
cording, it will be understood that for conventional
position of the multi-phase valve 17 0'.
drive of the vehicle, the multi-phase valve 170 does not
The displacement valve plunger, indicated in its en
affect the action of the displacement control valve 300
tirety as at 3114, is provided with a land 385 having a
and the displacement control valve 300 thus functions in
45
close sliding ?t in the bore which receives the plunger.
a manner described in detail in connection with my said
A land 3115a above the land 3% is provided with a lesser
diameter and is also provided with vertical grooves, or
the like, so that high ?uid pressure entering the body by
co-pending application, Serial No. 849,588.
When, however, the multi-phase valve is moved to the
position illustrated in FIG. 12, it will be observed that
way of line 167a is eifective over the upper side of the
the member 353 has been moved so that a land 357
land 3115. Beneath the land 3135 is an annular chamber 50 thereon prevents the ?uid coming from the displacement
3&6 formed on the plunger 3114 and a vertical groove 311
valve by Way of line 3G1 from moving out of the multi
is formed on the plunger beneath the annular space 306.
phase
valve by way of line 221.
The groove 311 thus opens the space 3116 vto chamber 312
The reduced diameter portion 358 on the member 353
which extends upwardly around the cup 31}? engaging the
places the passageway 351 in communication with a
plunger 3%. With the parts in the position as shown in
FIG. 14, the annular space 3% on the plunger 3114 is
also opened into the transverse bore 316 and the right
hand end of the vbore 316 in turn opens into an annular
space 315 on the flow sensing valve plunger 314. Ac
parallel passage 359. A bore 361) provided with check
valve 361 connects the space 250 in the multi-phase valve
170 in communication with the passageway 359.
in the foregoing description of the displacement valve
cordingly, the line 181, which leads to the displacement 60 3%, reference has been made to a mode of operation
control in the motors 171 and 172, is opened through the
path described so as to lower the pressure in line 181
and drain such ?uid pressure as may exist from line 181
outwardly through the line 3111 leading to the displace
ment valve 171}.
of the displacement valve 360 wherein hydraulic ?uid
under pressure is moved from the multi-phase valve 170
into the lower end of the displacement valve 309 and
such ?uid pressure in turn moves the drive motors to
maximum displacement position. The multi-phase valve
structure, illustrated in FIGS. 11, 12 and 13, includes a
check valve system which is e?ective to divert high ?uid
pressure into line 3111 leading from the multi-phase valve
face of the land 3115 and will be effective to overcome
170 to the displacement valve 300.
the spring 3118 around the cup 309 which spring nor
mally biases the plunger 3*.“34 to its upper position as 70 With the plunger in the position illustrated in FIG.
11, which is the position for normal ‘forward drive of
shown in full lines in FIG. 14. As the plunger 3%
the vehicle, line 3111 leads by way of inlet 35%) and pas
moves downwardly in response to such higher ?uid pres
sageway 351, thence through openings 354 formed in
sure, the land 3115 will be positioned so that its upper
the annular chamber 352 of the plunger 374 into the
surface opens into the transverse passage 316 and the
higher ?uid pressure is then moved into the annular 75 chamber 355 at the left-hand end of the valve body and
It will be observed that increasing ?uid pressure by
way of the line 167 a will be effective over the upper sur
3,039,638
17
18
outwardly of the valve body by way of line 221. The
of the outrigger raises the left-hand steering wheel from
the ?oor as illustrated in FIG. 6 and the displacement
control valve 170 is manually operated to rotate the front
check valve system includes a passageway 359 opening
into an annular chamber 358 formed on the outer sur
face of the left-hand end of the plunger 174. In the
position of the plunger 174 shown in FIG. 11 there is no
axle as illustrated in FIGS. 8 and 12.
outlet for the chamber 358 and no ?uid may move from
As described above, the drive wheels may be operated
at different rates in the same direction for guiding the
the interior of the multi-phase valve into line 301. When
vehicle accurately into stacking position.
the plunger 174 is in either the FIG. 12 or FIG. 13
position, the line 359 is open to the line 301 and the
check valve system is effective to transmit ?uid pressure
to valve 300.
The check valve system includes a branch 360 opening
into the space 250 and a second branch 359a having ball
check 35% leading by way of passage 365 into space 259
at the interior of the multi-phase valve 170. When ?uid
is moving into the multi-phase valve at high pressure by
way of line 207, the space 250 is ?lled with high pressure
?uid and a portion of such ?uid may move from the
chamber 250 by unseating the ball check 361 and thence
by way of line 359 into the annular space 358 and thence
When the left-hand outrigger is extended for maneuver
ing the vehicle into a stack, the linkage illustrated in
10 FIG. 2 is effective to'control the position of the dirigible
Wheels 16 and 17. Accordingly, when the vehicle is
maneuvered to the position of FIG. 8, the dirigible wheel
17 is brought into alignment with the outrigger 35. Thus,
in effect, the width or tread of the vehicle has been in~
15 creased to provide a width corresponding to the distance
-
between the wheel 17 and the wheel 35. This results in
great stability immediately adjacent the load which is
being handled on the forks.
Coincident with the hydraulic manipulation of the out
20 rigger and the drive axle, and the controls therefor, is
outwardly of the multi-phase valve by way of line 301.
the electrical interlock illustrated in FIG. 9. As de
During this condition of operation the ball check 35%
scribed in detail above in connection with the electrical
prevents high ?uid pressure in the check valve system
interlock, it is impossible for unskilled or inexperienced
from moving into space 259. This mode of operation is
operators to maneuver the vehicle into an unstable posi
illustrated in FIGS. 12 and 13.
25 tion. The electrical interlock provides a safety feature
In the event the manually operated plunger 173 in the
which stops the engine and thus the source of hydraulic
drive control valve 168 is reversed so that high ?uid pres
power in the event it is attempted to extend both out
sure enters the multi-phase valve by way of line 210, the
riggers at the same time or turn the drive axle before an
space 259 is ?lled with ?uid at high pressure. Such high
outrigger has been moved so as to permit the drive wheel
?uid pressure may be conducted by way of line 365 to 30 to be moved to the position shown in FIGS. 7 or 8.
unseat the ball check 35911 and thence by way of line 359
Coincident with the manipulation of the Outriggers, the
into the annular space 358 and outwardly of the multi
pilot operated check valves in the outrigger hydraulic
phase valve by way of line 301. During this mode of
circuit provides an hydraulic lock to hold the Outriggers
operation (FIGS. 12 and 13) the high ?uid pressure in
in their extended or retracted position.
line 359 and 359a maintains the ball check 361 closed 35 Although I have illustrated and described one form of
and prevents high ?uid pressure from entering the space
my invention in considerable detail, it will be appreciated
250.
by those skilled in the art that numerous variations may
Hydraulic ?uid returned from the motors after driving
be made therein without departing from the scope of the
the traction motors 171 and 172 is directed through the
invention as de?ned in the following claims.
conduits above described to the drive control valve 168. 40
What is claimed is:
The spent or low pressure hydraulic ?uid is moved from
1. A lift truck comprising a frame having a relatively
the drive control valve by way of line 222', thence through
wide rear portion supporting a power unit, dirigible
a ?lter 223 and line 224 to the reservoir 153. Line 221a
wheels carried beneath said rear frame portion, said frame
conducts ?uid from port 221b of the multi-phase valve to
having a relatively narrow centrally disposed forward por
the reservoir 153. The arrangement illustrated employ 45 tion, a transverse drive axle pivotally mounted at the
ing two pumps of different capacities and directing the
outer end of said narrow forward portion of the frame
output of one pump 152 in the ?rst instance to the out
rigger control valve and the output of the other pump 151
to the tilt-hoist valve results in an efficient utilization of
the power unit. The energy derived from the power unit
may be utilized to extend or retract the Outriggers and to
raise and tilt the load on the mast, which operations do
not ordinarily take place when the vehicle is moving.
Assuming the load is elevated and tilted on the mast and
to provide a space at each side of the lift truck between
the drive axle and the rear portion of the frame, an
outrigger arm pivotally mounted at each side of the lift
truck on the rear portion of the frame, an outrigger wheel
mounted on the free outer end of the outrigger arm,
means to swing the outrigger arm and the wheel carried
thereby from a storage position in said space at the side
of the lift truck to a laterally extended position at the
the outriggers have been retracted, then the energy of 55 side of the lift truck, means operatively connecting the
the power unit is available for driving the vehicle. At
outrigger arm and the dirigible wheels to align one of the
high speed operation of the vehicle the output of both
dirigible wheels with an outrigger wheel at the opposite
pumps 151 and 152 may be utilized for traction effective
side of the frame when the outrigger is extended, said
to move the load.
last-named means including a ?rst link moved by the
It is believed that the mode of operation and the ad 60 said one dirigible wheel and a second link moved by the
vantages obtained from the lift truck made according to
outrigger arm and a lost-motion connection between the
the instant disclosure will be apparent to those skilled in
?rst and second links whereby outrigger movement is
the art. Generally speaking, the adoption of the vehicle
for a warehouse results in allowing more than 35% more
material to be stored in a given ?oor area than with the
transmitted torthe dirigible ‘wheel but the dirigible wheel
may be moved independently of the outrigger.
2.‘ A lift truck comprising a frame having a relatively
wide rear portion supporting a power unit, dirigible
wheels carried beneath said rear frame portion, said frame
the vehicle by means of the wheel 57 in a conventional
having a relatively narrow centrally disposed forward por
manner, the internal combustion engine 150 is accelerated
tion, a transverse drive axle pivotally mounted at the
in the usual manner by a foot throttle and the position 70 outer end of said narrow forward portion of the frame
of the drive control valve 168 is determined by the foot
to provide a space at each side of the lift truck between
pedal engaged by the operator.
the drive axle and the rear portion of the frame, an
When it is desired to swing one of the outriggers, for
outrigger arm pivotally mounted at each side of the lift
example, the outrigger 27, for left-hand stacking, the left
truck on the rear portion of the frame, an outrigger wheel
hand lever 55 is moved by the operator. The extension 75 mounted on the free ‘outer end of the outrigger arm,
prior art vehicles. For conventional driving of the lift
truck, the outriggers are retracted. The operator steers
3,039,688
1%
means to swing the outrigger arm and the wheel carried
thereby from a storage position in said space at the side
of the lift truck to a laterally extended position at the
side of the lift truck, means on each outrigger engaging
means on said drive axle at opposite sides of the drive
20
to align a dirigible wheel on the other side of the lift
truck with the extended outrigger Wheel on said one side
of the lift truck.
5. A lift truck comprising a frame having a rear por
tion supporting a power unit and hydraulic pump means,
dirigible wheels carried beneath said rear frame portion,
means connecting the dirigible wheels for joint turning
arm and the dirigible wheels to align one of the dirigible
motion, a manual steering wheel for said dirigible wheels,
wheels with an outrigger wheel when the outrigger is
said frame having an elongated centrally disposed for
extended, said last-named means including a ?rst link
moved by the said one steering wheel and a second link 10 ward portion, a transverse drive axle pivotally mounted
on a vertical pivot at the outer end of said elongated for
moved by the outrigger arm and a lost-motion connection
ward portion of the frame to provide drive wheel and
between the links whereby outrigger movement is trans
outrigger storage space at each side of the lift truck be‘
mitted to the dirigible wheel, a steering wheel to turn the
tween the forward and the rear portion of the frame, an
dirigible wheels independently of the outrigger movement,
said independent turning of the dirigible wheels being 15 outrigger arm pivotally mounted at each side of the lift
truck on the rear portion of the frame, said Outriggers
accommodated by said lost-motion connection of said
being disposed in said storage space when retracted, an
links.
outrigger wheel mounted on the free outer end of the'
3. A lift truck comprising a frame having a relatively
outrigger arm, hydraulic cylinder means connected to‘
wide rear portion supporting a power unit, hydraulic pump
means driven by said power unit, dirigible wheels carried 20 said pump means to swing the outrigger arm and the
wheel carried thereby from a retracted position in said
beneath said rear frame portion, a steering wheel on the
storage space to a laterally extended position at the side‘
frame for manual turning of the dirigible wheels, said
of the lift truck, rigid parallel locking members ?xed to‘
frame having a relatively narrow centrally disposed for
said drive axle extending rearwardly therefrom adjacent
ward portion, a transverse drive axle pivotally mounted
the
drive wheels into said storage space at each side of
at the outer end of said narrow forward portion of the 25
the lift truck, a locking lug carried by each of said out
frame to provide a space at each side of the lift truck
riggers at the extreme outer free end thereof, said lugs
between the drive axle and the rear portoin of the frame,
being
engaged with said locking members to prevent piv
an outrigger arm pivotally mounted at each side of the
otal movement of the drive axle into said storage space
lift truck on the rear portion of the frame, an outrigger
wheel mounted on the free outer end of each outrigger 30 on one side when the outrigger is retracted on said one
side of the frame, said pivotal mounting of the outrigger
arm, interengaging lugs on the drive axle and the out
on
the frame being inclined to raise the outrigger wheel
riggers, means to swing one outrigger arm and the wheel
to a higher position relative to the lift truck when re
carried thereby from a storage position in said space at
tracted and to lower the outrigger wheel relative to the
the side of the lift truck to a laterally extended position
at the side of the lift truck, said movement of the out 35 lift truck when extended.
6. A lift truck comprising a frame having a relatively
rigger freeing its lug from the drive axle, means’ opera
wide rear portion supporting a power unit, dirigible wheels
tively connecting the outrigger arm and the dirigible
carried beneath said rear frame portion, a steering wheel,
Wheels to align one of the dirigible wheels with an oppo
axle pivot, means operatively connecting the outrigger
site side outrigger wheel when the outrigger is extended,
means connecting the steering wheel and said dirigible
ing wheel independently of the outrigger, hydraulic drive
to provide drive wheel and outrigger storage space at
said last-named means including a pair of links having 40 wheels, said frame having a relatively narrow centrally
disposed forward portion, a transverse drive axle pivotally
a lost-motion connection between the links whereby out
mounted at its mid-portion on a vertical pivot at the
rigger movement is transmitted to the dirigible wheel but
outer end of said narrow forward portion of the frame
the dirigible wheel may be moved manually by the steer~
motor means on the drive axle to turn the same in the
direction of an extended outrigger, and valve and conduit
means to direct fluid from said pump means to the drive
motors and the means for swinging the Outriggers.
4. A lift truck comprising a frame having a relatively
wide rear portion supporting a power unit and hydraulic
pump, dirigible wheels carried beneath said rear frame
portion, rocker means pivoted on the frame connecting
the dirigible wheels to each other for joint turning move
ment, said frame having a relatively centrally disposed
forward portion, a manually operable steering wheel con
nected to said rocker means, a transverse drive axle pivot
ally mounted on a vertical pivot at the outer end of said
forward portion of the frame to provide a space at each
side of the lift truck between the drive axle and the rear
portion of the frame, an outrigger arm pivotally mounted
at each side of the lift truck on the rear portion of the
frame, an outrigger wheel mounted on the outrigger arm,
each side of the lift truck between the forward portion
of the frame and the rear portion of the frame, an outrigger arm pivotally mounted on an inclined pivot at
each side of the lift truck on the rear portion of the frame‘,
an outrigger wheel mounted on the free outer end of the
outrigger arm, means to swing the outrigger arm and the‘,
wheel carried thereby from a raised position in said
storage space to a lower laterally extended posi
tion at the side of the lift truck, rigid locking bars
carried by said drive axle and extending rearwardly there
from adjacent the drive wheels into said storage space
at each side of the lift truck, a locking lug carried by
each of said Outriggers at the extreme outer free end'
thereof, said locking lugs being in engagement with the
outer free end of said locking bars to prevent movement
of the drive axle about its pivot into said storage space:
when the outrigger is retracted.
7. A lift truck comprising a frame having a rear por»
tion, dirigible Wheels carried beneath said rear frame por
tion, rocker means connecting the dirigible wheels for
pump to swing one outrigger arm and the wheel carried
thereby from a position in said space to a laterally ex 65 joint turning movement, said frame having a relatively
narrow centrally disposed forward portion, a transverse
tended position at one side of the lift truck, links con
drive axle pivotally mounted at the outer end of said
necting the said outrigger and said rocker means, parallel
hydraulic cylinder means connected to said hydraulic
member's ?xed to said drive axle extending rearwardly
therefrom adjacent the drive wheels into said storage
narrow forward portion of the frame to provide a space
at each side of the lift truck between the front and rear
space at each side of the lift truck, a lug carried by each
of said outriggers at the extreme outer free end thereof,
said lugs being aligned to engage with the outer free end
frame, said pivot mounting for the outrigger arm being
portions of the frame, an outrigger arm pivotally mounted
at each side of the life truck on the rear portion of the
inclined rearwardly, an outrigger wheel mounted on the
free outer end of the outrigger arm, means to swing the
of the drive axle into said storage space when the out
rigger is retracted, said links moving said rocker means 75 outrigger arm and the wheel carried thereby from an ele~
of said parallel members to prevent pivotal movement
3,039,638
21"
vated storage position in said space at the side of the lift
truck to a lower laterally extended position at the side of
the lift truck, a manually operable steering wheel for nor
mal guidance of the lift truck by the operator with the
Outriggers retracted, said rocker means including a rocker
bar pivoted intermediate its ends to the frame, a recipro
cating link connected to said rocker bar at each side of
its pivot mounting, said reciprocating links being moved
longitudinally of the frame in response to joint turning
22'
to the outrigger and to the dirigible wheels, said last-named
connection providing a lost-motion coupling between the
outrigger and the dirigible wheels effective to turn said
dirigible wheels in response to outrigger movement.
10. A lift truck comprising a frame having a relatively
wide rear portion, a power unit, hydraulic pump means
driven by said power unit, dirigible wheels beneath said
relatively wide rear portion of the lift truck, a steering
wheel arranged above the frame for manual turning of
movement of the dirigible wheels, a bell crank mounted 10 said dirigible wheels, said frame having a narrow elon
on the lift truck frame adjacent each outrigger, a ?rst
gated neck projecting forwardly at the longitudinal center
bell crank link connecting one arm of the bell crank to
thereof, a drive axle pivotally connected at the outer end
the outrigger and a second bell crank link connecting the
portion of said forwardly extending neck, an outrigger
other arm of the bell crank to said reciprocating link,
arm pivotally mounted on the frame adjacent the dirigible
said last-named connection to the reciprocating link pro
wheels, an outrigger wheel carried at the outer end of each
viding a lost-motion coupling whereby movement of an
outrigger arm, double-acting hydraulic cylinder means
outrigger is effective to turn said dirigible wheels but
interposed between the outrigger arm and the frame to
movement of the dirigible wheels by the said manually op‘
swing the outrigger from an extended position laterally
erable steering wheel is independent of outrigger move
of the lift truck into a retracted storage position along
ment.
the side of the lift truck, valve and conduit means inter
8. A lift truck comprising a frame having a relatively
posed between said hydraulic pump and said double-act
wide rear portion, dirigible wheels carried beneath said
ing hydraulic cylinder means for controlling the move
rear frame portion, said frame having a relatively narrow
ments of the outrigger, pilot check valve means in said
centrally disposed forward portion, a drive axle mounted
conduits to provide a hydraulic lock for holding the out
at the outer end of said narrow forward portion of the 25 rigger in its extended and retracted position.
frame to provide a storage space at each side of the lift
11. A lift truck comprising a frame having a rear por
truck between the drive axle and the rear portion of the
tion supporting a power unit, hydraulic pump means driven
frame, said drive axle pivotally mounted for rotation from
by said power unit, dirigible wheels beneath said rear por
a ?rst position normal to the longitudinal center line of
tion of the lift truck, a steering wheel arranged above the
the lift truck to a second position in alignment with said
frame for manual turning of said dirigible wheels, said
center line, an outrigger arm pivotally mounted at each
frame having a drive axle mounted at the forward end
side of the lift truck on the rear portion of the frame, an
outrigger wheel mounted on the free outer end of the out
rigger arm, means to swing the outrigger arm and the
thereof, an outrigger arm pivotally mounted on the frame
wheel carried thereby from an elevated storage position in
hydraulic cylinder interposed between the outrigger arm
said space at the side of the lift truck to a lower laterally
extended position at the side of the lift truck, a steering
and the frame to swing the outrigger from a lower ex
tended position laterally of the lift truck into a higher stor
age position along the side of the lift truck, a conduit in
adjacent the dirigible wheels, an outrigger wheel carried
at the outer end of each outrigger arm, a double-acting
wheel for guidance of the lift truck by the operator with
the drive axle in said ?rst position and the outriggers re
terposed between said hydraulic pump and opposite ends
tracted, an oscillating bar connected to each of said 40 of said double-acting hydraulic cylinder means for direct
dirigible wheels, said bar being pivotally mounted on said
ing fluid into the cylinder and controlling the movements
rear frame portion, a bar link mounted at each end of said
of the outrigger, pilot check valve means in each of said
bar, each link being moved longitudinally of the vehicle in
conduits to provide a hydraulic lock for holding the out
response to turning movement of the dirigible wheels, a
rigger in either extended or retracted position.
bell crank mounted on the lift truck frame adjacent each
12. A lift truck comprising a frame having a relatively
outrigger, ?rst means connecting one portion of the bell
wide rear portion supporting a power unit, hydraulic pump
crank to the outrigger and second means connecting an
means driven by said power unit, dirigible wheels beneath
other portion of the bell crank to said bar link, said last
said relatively wide rear portion of the lift truck, a steer
named connection providing a lost-motion coupling be
ing wheel arranged above the frame for turning said dir
tween the second means and said bar link whereby move
igible wheels to guide the lift truck for forward drive,
ment of the outrigger is effective to turn one of said
said frame having a narrow elongated upwardly arched
dirigible wheels and movement of a dirigible wheel by the
neck projecting forwardly at the center thereof, a drive
steering wheel is independent of outrigger movement.
axle pivotally connected at the outer end portion of said
9. A lift truck comprising a frame having a rear por
forwardly extending neck, drive wheels at each end of the
tion, a power unit and pump driven by the power unit, 55 drive axle, hydraulic motor means for each drive wheel
dirigible wheels carried by said rear frame portion, said
to turn the drive axle to position one drive wheel under
frame having a centrally disposed forward portion, a drive
said upwardly arched neck portion, an outrigger arm
axle mounted at the outer end of said forward portion
pivotally mounted on the frame adjacent the dirigible
of the frame to provide a space at each side of the lift truck
wheels, an outrigger wheel carried at the outer end of each
between the drive axle and the rear portion of the frame,
outrigger arm, double-acting hydraulic cylinder means
said drive axle being pivoted on the frame for movement
interposed between the outrigger arm and the frame to
to a ?rst position transverse of the vehicle and to a second
swing the outrigger from a storage position to an extended
position with the axle aligned longitudinally of the Ve
position laterally of the lift truck whereby said one drive
hicle, hydraulic motor means on the drive axle to turn
wheel may be positioned under said arched neck, valve
the drive wheels, an outrigger arm pivotally mounted at
and conduit means interposed between said hydraulic
each side of the lift truck on the rear portion of the frame,
pump and said double-acting hydraulic cylinder means for
an outrigger wheel mounted on the free outer end of the
controlling the movements of the outrigger, pilot check
outrigger arm, hydraulic cylinder means to swing the out
rigger arm and the wheel carried thereby from a storage
position in said space at the side of the lift truck to a lower
laterally extended position at the side of the lift truck, a
valve means in said conduits to provide a hydraulic lock
for holding the outrigger in either said extended or re
steering wheel for guidance of the dirigible wheels by the
operator with the Outriggers retracted and the drive axle
tracted position,
13. A lift truck comprising a frame having a relatively
wide rear portion supporting a power unit, hydraulic pump
means driven by said power unit, dirigible wheelsbeneath
said relatively wide rear portion of the lift truck, a
frame adjacent each outrigger, means connecting the crank 75 steering wheel for turning said dirigible wheels to guide
in said ?rst position, a crank mounted on the lift truck
3,089,638
23
the lift truck for normal forward drive, said frame having
a narrow elongated neck projecting forwardly at the center
thereof, a drive axle having drive wheels, said axle being
pivotally mounted on a vertical pivot at the outer end
portion of said forwardly extending neck to provide a
storage space at each side of the vehicle between the drive
wheels and the dirigible wheels at the rear of the lift truck,
an outrigger arm at each side of the lift truck, said arm
having one end thereof pivotally mounted on the frame
ment of the drive motors, a manually operable multi
phase valve to effect different phases of hydraulic opera
tion of the drive motors, conduit means connecting the
output of the ?rst pump to said tilt-hoist valve, conduit
means connecting the output of said second pump to said
outrigger control valve and conduit means to direct the
carry-over of the output from both pumps at the tilt
hoist and outrigger valves to said vehicle drive control
valve, and conduit means to direct hydraulic ?uid to
adjacent the dirigible Wheels, an outrigger wheel carried 10 said drive motors through said vehicle_drive control valve
and through said multi-phase valve.
at the outer end of each outrigger arm, hydraulic cylinder
15. A lift truck of the type having an outrigger at each
means connected to said pump and having a piston rod
side of the truck and having a drive axle pivoted for rota
connected to the outrigger arm to swing the outrigger
tion relative to the lift truck frame from a position trans
from a lowered extended position laterally of the lift truck
into an elevated position in said storage space between 15 verse of the truck to a position longitudinally of the
truck, a power unit, hydraulic pump means driven by
the drive wheels and the dirigible wheels, said power
said power unit, a drive wheel at each end of said pivoted
unit comprising an internal combustion engine having a
drive axle, a variable displacement motor for each drive
battery-powered ignition system, said ignition system in
wheel, said outriggers being pivoted to the frame of the
cluding an electric circuit means interposed between said
lift truck, hydraulic cylinders interposed between the
battery and said power unit, switch means in said circuit
frame and each outrigger to swing the outrigger from
operatively connected to said outriggers, a manually oper
a storage position alongside of the lift truck frame to a
able hydraulic valve member for each outrigger cylinder
position extending laterally of the lift truck frame, an
means, a valve switch operatively connected to each of
outrigger control valve for said outrigger cylinders, a
said manually operable valve members, a drive axle switch
moved by said drive axle in response to axle turning move 25 mast structure carried by said drive axle, a load platform
mounted on said mast structure, hydraulic cylinder means
ment about its vertical pivot, said valve switch and said
for tilting the mast, hydraulic cylinder means for hoist
drive axle switch and said outrigger switches connected
ing said load platform, a tilt-hoist valve for tilting and
in said circuit between the battery and the power unit to
hoisting cylinders, a manually operated vehicle drive con
stop the power unit and pump in response to opening of
trol valve, a displacement valve responsive to torque
both outrigger switches at the same time.
demand at the drive wheels to vary the displacement of
14. A lift truck of the type having an outrigger at
the drive motors, a manually operable multi-phase valve
each side of the truck and having a drive axle pivoted
to effect different phases of rotation of the drive motors
for rotation relative to the lift truck frame, a power unit,
for guiding the lift truck for stacking, conduit means
a ?rst hydraulic pump and a second hydraulic pump
driven by said power unit, said ?rst hydraulic pump hav 35 connecting the output of the pump means to said tilt
hoist valve, conduit means connecting the output of said
ing a capacity of about twice the capacity of the second
pump means to said outrigger control valve, conduit
hydraulic pump, a drive wheel at each end of said pivoted
means to direct the carry~over of the output from the
drive axle, a variable displacement motor for each drive
pump means to said vehicle drive control valve, and con
wheel, said Outriggers being pivoted to the frame of the
lift truck, double-acting hydraulic cylinders interposed 40 duit means to direct hydraulic ?uid from said tilt-hoist
and outrigger valves to said drive motors through said
between the frame and the outrigger to swing the out
drive control valve and through said multi-phase valve in
rigger from a storage position alongside of the lift truck
the sequence named.
frame to a position extending laterally of the lift truck
frame, an outrigger control valve, a mast structure car
ried by said drive axle, a load platform mounted on said 45
mast structure, hydraulic cylinder means for tilting the
mast, hydraulic cylinder means for hoisting said load
platform, a tilt-hoist valve for directing ?uid to said
hoisting and tilting cylinders, a manually operated vehicle
drive control valve, a displacement valve responsive to 50
torque demand at the drive wheels to vary the displace
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,774,436
2,789,648
2,986,295
Ferris ________________ __ Dec. 18, 1956
Huffman _____________ __ Apr. 23, 1957
Shaffer _______________ __ May 30, 1961
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