close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3091315

код для вставки
May 28, 1963
3,091,305
E. C. PICKARD ETAL
HYDRAULICALLY OPERATED PORTABLE SCAFFOLD
Filed April 28. 1961
5 Sheevts-Sheet 1
May 28, 1963
E. c. PICKARD ETAL
3,091,305
HYDRAULICALLY OPERATED PORTABLE SCAFFOLD
5 Sheets-Sheet 2
Filed April 28, 1961
14d
1*" -.2.
B V.
.27arm/@“m{a/ a?”WT/MFR.T
‘e15
a
T14; 50
My
Men” Mr.
May 28, 1963
E. c. PICKARD ETAL
3,091,305
HYDRAULICALLY OPERATED PORTABLE SCAFFOLD
Filed April 28. 1961
5 Sheets-Shéet 3
their‘
3
May 28, 1963
E. c. PICKARD ETAL
3,091,305
HYDRAULICALLY OPERATED PORTABLE SCAFFOLD
Filed April 28, 1961
5 Sheets-Sheet 4
May 28, 1963
E. c. PICKARD ETAL
3,091,305
HYDRAULICALLY OPERATED PORTABLE SCAFFOLD
Filed April 28, 1961
5 Sheets-Sheet 5
Mm
3,091,305
Patented May 28, 1963
1
2
Although hydraulic pump-motors will meter the proper
HYDRAULICALLY OPERATED PORTABLE
SCAFFOLD
3,091,305
amount of ?uid to the cylinders on the upward stroke
of the platform, it has been found that when it is desired
to lower the platform, its weight will not be sufficient
Edgar C. Pickard, Glenshaw, Pa, and William R. .lacie
son, Youngstown, and George A. Grappo, East Pales
to overcome the internal resistance of the pump-motors
so as to force ?uid out of the cylinders and collapse the
tine, Ohio, assignors to Fordees Corporation, Leetonia,
same. Accordingly, in accordance with another aspect
of the invention, means are provided for forcibly driving
Filed Apr. 28, I961, Ser. No. 106,310
all pump-motors when it is desired to lower the platform
$ Claims. (ill. 182-141)
10 whereby the pump-motors will expel ?uid from each of
the cylinders at controlled rates to maintain the platform
This invention relates to portable elevator apparatus
level and prevent any binding of cylinders.
and more particularly to a hydraulically elevatablle plat
The above and other objects and features of the in
form adapted to replace conventional scaffolding used in
vention will become apparent from the following detailed
masonry work and other similar applications.
Although not limited thereto, the present invention is 15 description taken in connection with the accompanying
drawings which form a part of this speci?cation, and in
particularly adapted for use in applications where it is
which:
necessary to provide a scaffold for supporting men and
FIGURE 1 is a side elevational view of the portable
materials above ground level. Such applications include,
scaffold of the invention;
for example, the erection of building walls or replacing
FIG. 2 is ‘an end view of the scaffold shown in FIG. 1
the brickwork in the slag pockets and uptakes of a steel 20
and
illustrating in dotted outline the expanded or elevated
making open hearth furnace.
position of the platform;
In the past, scaffolding has usually been erected man
FIG. 3 is a top view of the base and cylinder arrange
ually from lumber or fabricated steel sections which may
ment of the invention taken substantially along line
be locked together one above the other. The erection
and dismantling of such scaffolding, however, is costly, 25 Ill-~III of FIG. 1;
FIG. 4 is a cross-sectional view of the ?uid metering
time consuming and sometimes dangerous. In addition,
motors of the invention taken substantially along line
since scaffolding of this type must be built up in layers
-lV—IV of FIG. 3;
or tiers, it has the disadvantage of sometimes requiring
FIG. 5 is a cross-sectional view taken along line V--V
the workman on the scaffold to stoop below or reach above
30 of FIG. 4; and
a comfortable working level where he functions most
FIG. 6 is a schematic diagram of the ?uid control cir'
efficiently.
cuit for the apparatus shown in FIGS. 14.
As ‘an overall object, the present invention seeks to
Referring now to the drawings, and particularly to
provide a portable, hydraulically elevatable platform
which may be used to replace conventional scaffolding or 35 FIGS. 1, 2 and 3, the portable scaffold shown includes
a fabricated base 10 supported on a plurality of wheels
for elevating heavy articles and other similar applications.
12, it being understood that the wheels may ‘be replaced
More speci?cally, an object of the invention is to pro
by crawlers or other ground-traversing means. Carried
vide 1a hydraulically elevatable platform of the type de
on the base 10 are six vertically expandable telescoping
scribed which provides for automatic, or at least semi
automatic, raising or lowering of workmen and materials 40 hydraulic cylinders 14a, 14b, 14c, 14d, 14c and 14)‘. As
shown, each of the cylinders 1411-14)‘ is supported in
to any desired height.
an upright or vertical position by a plunality of gussets 16,
Still another object of the invention is to provide ap
these gussets being circumferentially spaced around each
paratus for expanding or collapsing a plurality of tele
cylinder. Positioned on the tops of the cylinders
scoping hydraulic cylinders or the like at the same rate
14a_14f is an elevatable platform 18 having a plurality
so as to maintain a platform supported on those cylinders
slideable, retractable bars or arms 20 around its periphery
in a horizontal plane at all times.
on all four sides of the platform. These ‘arms may be
In accordance with the invention, there is provided a
Ohio, a corporation of Ohio
base mounted on wheels or crawlers and which carries
selectively extended to support planks 22 (FIG. 2) where
metering devices are provided for delivering controlled
manner hereinafter described.
by the cross-sectional area of the platform 18 may be
a plurality of telescoping, hydraulic cylinders or rams
effectively increased.
adapted to rise in a vertical direction. Supported by these
Also supported on the base 10 is an electric motor 24
rams is a horizontal platform, the arrangement being
which drives ‘a hydraulic pump, generally indicated lat 26.
such that the platform may be raised or lowered as the
At the right end of the base 10 as shown in FIGS. 1 and
hydraulic rams are raised or retracted, respectively.
3 is an operator’s console 28 having a plurality of valve
In order to maintain the platform horizontal at all
times and to prevent bending of the cylinders or rams 55 control levers 3t} thereon, the purpose of these levers being
to operate valves which, in turn, control the various hy
due to unequal loadings, it is necessary to raise and re
draulic operating instrumentalities of the scaffold in a
tract all cylinders at the same rate. Accordingly, ?uid
Carried at the four corners of the base '10, adjacent
embodiment of the invention shown herein, the ?uid 60 the wheels 12, are four hydraulic jacks 32a, 32b, 32c and
l32d. Each of the jacks 32a——32d comprises a hydraulic
metering devices comprise hydraulic pump-motors which
cylinder having a pad 34 secured to the end of its piston
are geared together such that ‘all pump-motors will oper
rod and adapted to engage the ground surface when the
ate in synchronism and deliver the proper amount of ?uid
hydraulic cylinder is pressurized to move its piston down
under pressure to each cylinder.
amounts of ?uid under pressure to ‘all cylinders. In the
3,091,305
3
4
wardly. The purpose of the jacks 32c-32d is to level
the base 10 and the platform 18 carried thereby. In this
respect, levels 36 are provided at the four corners of
the base 10. As will hereinafter be explained, each
as an input port while the other is used as an output port.
By introducing ?uid pressure into one of the ports of any
one of the pump-motors 4411-441‘, it will act as a motor
to drive all other pump-motors in synchronism. Fur
of the jacks 32a—32d is provided with an associated
thermore, even though pressure is delivered to a plurality
one of the control levers 30, the arrangement being such
that each lever may be actuated to either raise or lower
of the pump-motors, they will operate in synchronism to
deliver ?uid at their output ports at the same rate by
virtue of the fact that they are all mechanically inter
jacks 32a~32d will be pressurized to engage the pads
connected through the gears 54a—54f and gear 56.
34 with the ground surface. Thereafter, the base 10 and 10
The hydraulic control circuit for the scaffold of the
platform 18 may be leveled by adjusting the various jacks
invention is shown in FIG. 6‘. It comprises the motor ‘24
while observing the levels 136 at the four corners of the
which drives pump 26 through mechanical linkage 68.
base.
The pump input port 70‘ is connected to a hydraulic
In using the scaffold of the invention, it will ?rst be
reservoir 72 as shown, while the pump output port 74
rolled into position on wheels 12 and the jacks 32a—32d
is connected through conduit 76 to the input ports 78
thereafter pressurized to fix the base 10 in position and
and 79 of each of ?ve control valves 80, 82, 84, 86 and
level the same. Thereafter, the six telescoping cylin
88. Each of the valves 80-88 may be of the self-center
ders \14a——14f may be pressurized to elevate the platform
ing type provided with a valve member 90 having springs
18 to any desired position, the fully extended position
92 and 94 which serve to center the valve member into
of the platform being shown in dotted outline in FIG. 2. 20 the positions shown in FIG. 6-. The valve member 90
In order to prevent binding of the cylinders 14a—14f
of each valve is actuated by means of one of the levers
during the time that the platform 18 is elevated or low
30a—30e mounted on the operator’s console 28 shown
ered, and to maintain the platform level, it is necessary
in FIGS. 1 and 3. With reference to valve 80, when
that all cylinders expand at the same rate. Since all cyl
the operator’s lever 30a is depressed, the valve member
inders are of the same size in the embodiment of the in
90 for this valve will move downwardly; whereas when
vention shown herein, this means that ?uid under pres
the operator’s lever ‘30a is moved upwardly, the valve
sure must be delivered to, or expelled from, each one
member 90 will also move upwardly. When, however,
of the cylinders 14a~14f at the same rate.
the lever 30a is released, the valve member 90 will al
In order to facilitate expansion or contraction of the
ways return to its central position shown in FIG. 6.
cylinders 14a-14f at the same rate, means including
Each valve 80-88 is provided with ?ve output ports
one of the pressure pads 34. In this manner, each of the
?uid metering apparatus, generally indicated at 38, is
08, 100, 102, 104 and 106, these ports being identi
provided. With reference to FIG. 3, it will be noted that
the ?uid metering apparatus 38 is mounted between a
pair of plates 40 and 42 which extend upwardly from
one side of the base 10. The ?uid metering apparatus
includes seven hydraulic pump-motors 44[l—-44g circum
ferentially spaced around a common axis.
As shown in FIGS. 3 and 4, the ?uid metering ap
?ed with numerals only with respect to valves 80‘ and 88,
it being understood that the other valves are identi
cal. The input port 79 of valve 80 is connected
through conduit 76 as shown to the output port 74 of
pump 26. The input port 79, of each succeeding
valve 30b—30e, on the other hand, is connected to
the output port 106 of the preceding valve in the system,
paratus 38 is mounted on a circular plate 46 having a
the arrangement being such that with all valves in neutral
cup-shaped cover ‘48 secured to its outer periphery as by
position, ?uid will ?ow from pump 26 through the input
‘means of'bolts' 50. ‘The cover 48, in turn, is secured by
and output ports 79 and 106, respectively, of each valve
means of bolts or other suitable fastening means, not
80-88 to the reservoir 72 through conduit 81. When,
shown, to the plate 40. As shown, the hydraulic pump
however, any one of the levers 30a-30'e is moved upward
motors 44a——44f are bolted or otherwise securely fas
ly or downwardly, the serial path from the output of
tened to the circular plate 46 and are provided with 115 the pump to the reservoir 72 will be blocked. The out~
shafts 52a—52f which extend through associated open
put port 100 of valve 80, for example, is connected to
ings in the circular plate 46. Connected to each of the
one side of the hydraulic jack 32a having a piston 33a
shafts 52a—52-f are pinion gears 54a—54f which mesh
therein; while the output port 102 of this same valve is
with a large central idler gear 56 rotatable about an
connected to the other side of the hydraulic jack 32a. In
axis 58 which coincides with the axis about which the
terposed in parallel between output port 100 of each
pump-motors 44a—44f are circumferentially spaced. As
valve 80-86 and the top of each jack are a check valve
Will be understood, the gear ‘56, together with the gears
183 and metering valve 105. Similarly, a check valve
54a-54f comprises a planetary gear arrangement where
107 and metering valve 109 are connected in parallel be
in all of the gears 54tZ——-54f must rotate in synchronism,
tween output port 102 of each valve 80-86 and the bottom
thereby causing all of the pump-motors 44a——44f to also
of each jack. The check valves Will permit ‘free ?ow of
operate in synchronism.
?uid into the top or bottom of their associated jacks, while
The pump-motors 44a—44f may, for example, be of
the metering valves will throttle the discharge of ?uid
the type manufactured by the Dennison Engineering Com
therefrom, thereby providing for slow, rather than rapid,
pany of Columbus, Ohio, and designated Model TMB
actuation of the jacks. That is, when ?uid under pres
lilF. A device of this type may be used as a hydraulic 60 sure is introduced into the bottom of jack 32a through its
pump or as a hydraulic motor interchangeably without
adjustment or alteration. Alternatively, the devices
44a—44f may comprise hydraulic gear motors.
As shown in FIG. 5, each pump-motor unit consists
of three major components: A housing 60 which pro
vides a port connection 61 and a support for the bear
ings which carry the shafts 52a-5~2f; a pump cartridge,
not shown herein in detail, consisting of a rotor, vanes
and cam rings; and a cap 64 with a port connection 66.
Each pump-motor 44a—44f will operate in either direc
tion of rotation as a pump or motor.
Changing the di
check valve 107, for example, the metering valve 105 at
the top of the jack will prevent too rapid movement of
the piston 33a under the high pressure from pump 26.
In a similar manner, the output ports 100 and 102 of/each
of the valves 82, 84 and 86 are connected through valves
103, 105 and 107, 109 to opposite sides, respectively, of
the jacks 32b, 32c and 32d. The remaining output ports
98 and 104 of each of the valves ‘80-88 are connected
through conduit 81 to the ?uid reservoir 72.
When the actuating lever 30a, for example, is pushed
downwardly, the connection between the input and output
ports 79 and v104 of valve 80 will be blocked while input
rection of shaft rotation reverses the direction of ?ow
when used as a pump; while changing ?ow reverses
port 78 will be connected to output port 102 to deliver ?uid
direction of shaft rotation when used as a motor. Thus,
under pressure to the bottom of the jack 32a through its
either one of the ports 66 or 61 may be alternately used 75 associated check valve 107, thereby forcing piston 33a
3,091,305
and the pad 34 associated with this jack upwardly, thus
lowering the machine. At the same time, the output port
100 of valve 80 will be connected to output port 98 which
communicates With the reservoir 72 so that the ?uid from
6
platform 18, the arrangement being such that when the
cylinders 14a~14f are completely collapsed and the plat
form is in its lowermost position, the cam 121 will
engage valve 120 to close the same, thereby stopping rota
tion of pump-motor 44g and the other pump-motors con
nected thereto. During this time ?uid will not ?ow
the upper end of the jack 32a will be expelled through
its associated metering valve 105 to the reservoir. To
through the check valve 1'23 connected in parallel with
raise the machine, the lever 38 is merely raised. Under
valve 120, however, the valve 123 will open when the
these circumstances, the connection between ports 79 and
direction of ?uid ?ow through the pump-motor 44g is
106 will again be blocked, but now input port 96 will ‘be
connected to output port 1%, thereby pressurizing the 10 reversed (i.e., when it is being driven by the other pump
motors Mal-44f) to permit the platform 18 to be raised
upper end of jack 32a while expelling liquid ‘from the
from its lowermost position when cam 121 closes
lower end of the jack which is now connected to reservoir
valve 129.
72 through ports 1112 and 1G4.
‘It can thus be seen that the present invention provides
The operation of valves 82—86 is identical to that de
scribed with respect to valve 81), and it will be understood 15 metering devices (i.e., pump-motors 4412-44)‘) for supply
ing ?uid at the same rate to all of the cylinders 1411-14)‘
that by proper manipulation of these valves, the base 10
to expand all cylinders in synchronism and maintain the
and platform .18 carried thereby may be leveled.
platform 13 level While preventing any binding in the
With reference to valve 88, its output port rat is con
cylinders. At the same time, the pump-motor 44g serves
nected through the parallel combination of check valve
112 and metering valve ‘113 and conduit 114 to the input 20 to drive the remaining pump-motors to expel liquid from
the cylinders 14a~14f and collapse the same at the same
ports of each of the hydraulic pump-motors 4411443‘.
rate to maintain the platform level while preventing any
The output ports of these same pump-motors are each con
binding of the cylinders. ‘It has been found that in the
nected through an associated valve 116a-11‘6f to one of
absence of means such as pump-motor 44g for driving the
the telescoping hydraulic cylinders 14a—-14f. Thus, in
order to expand the cylinders 141144)", the actuating lever 25 remaining pump-motors, the weight of the platform 18
will not be su?icient to collapse the cylinders.
30:? on the operator’s console 28 will be pulled upwardly
Although the invention has been shown in connection
whereby input port 78 of valve ‘88 will be connected to
with a certain speci?c embodiment, it will be readily
output port 100. Under these circumstances, ?uid under
pressure is delivered through each one of the pump-motors
4411-44)‘ to an associated one of the telescoping cylinders
14a—14f. -By virtue of the fact that all of the pump
motors ‘Ma-44f are mechanically interconnected through
gears 56 and 54a—54g (schematically illustrated by the
apparent to those skilled in the art that various changes
in form and arrangement of parts may be made to suit
requirements Without departing from the spirit and scope
of the invention.
We claim as our invention:
1. Apparatus for elevating a substantially horizontal
platform comprising a plurality of vertically disposed
nism to deliver ?uid to its associated telescoping cylinder 35 expandable
hydraulic cylinder devices positioned at spaced
at the same rate. Consequently, all cylinders will expand
points beneath said platform, each of said hydraulic cylin
in synchronism to maintain the platform 18 level and
der devices having the same volumetric capacity and all
prevent any binding in the cylinders.
of
said cylinder devices being adapted to expand in syn
When the actuating lever see was moved upwardly, it
chronism in response to like rates of ?uid flow into the
served also to connect output port 102 of valve 813
cylinders, hydraulic pumping means for supplying ?uid
to the ?uid reservoir 72 through output port 104. The
under pressure to said hydraulic cylinder devices, a plural
port 102, it will be noted, is connected through conduit
ity of hydraulic motors each having an inlet port con
dotted line in FIG. 6), each one must operate in synchro
118 and valve 120 .to one port of the seventh or last pump
nected to said hydraulic pumping means and an outlet
port connected to an associated one of said hydraulic
The valve 120 45 cylinder devices, and idler means mechanically intercon
will be normally open; and, consequently, when the cyl
necting all of said hydraulic motors to cause the same to
inders 14a~14f are being expanded, the pump-motor 44g
operate in synchronism and deliver ?uid under pressure to
will merely act as a pump to deliver ?uid from the res
each of the hydraulic cylinder devices at the same rate.
motor 44g. The other port of the pump-motor 44g is
connected, as shown, to the reservoir 72.
ervoir 72 through valve 124), conduit 118, valve 88 and
conduit 81 back to the reservoir.
When, however, the actuating lever 30a is moved down
wardly, the input port 7 8 will be connected to output port
1192, thereby delivering ?uid under pressure through con
duit 118 and valve 120 to the pump-motor 44g which, in
2. Apparatus for elevating a substantially horizontal
50 platform comprising a base, a plurality of vertically
expandable hydraulic cylinder devices positioned between
said base and said platform at spaced points, each of said
hydraulic cylinder devices having the same volumetric
capacity, a plurality of hydraulic pump-motors each hav
turn, causes the gear 56 shown in FIG. 4 to rotate and 55 ing an inlet port connected to said hydraulic pumping
drive all of the remaining pump-motors ‘Ma-44f in syn
means, an outlet port for each pump-motor connected to
chronism, but in a direction opposite to that in which they
an associated one of said hydraulic cylinder devices, gear
vare driven when the cylinders 14a—14f are being expanded.
means operatively connected to each pump~rnotor and
Consequently, during this time, the pump-motors Lida-44f
adapted to be rotated by a ?ow of ?uid under pressure
serve to dispel liquid from each of the cylinders 14a-14f 60 between said inlet and outlet ports, each of said hydraulic
at the same time. The pump-motors 4401-44)‘ are now
pump-motors being circumferentially spaced about a com
connected through conduit 114 and valve 112 to output
mon axis, and idler gear means rotatable about said com
port 100 which, in turn, is now connected to output port
mon axis and operatively connected to the gear means
98 which leads to the reservoir 72. In order to lock the
operatively connected to each of said hydraulic pump
various cylinders K14a—14f in their expanded positions, the 65 motors whereby all of the pump-motors will operate in
normally open valves 116414161’ may be closed. A meter
synchronism to deliver ?uid under pressure to each of
ing valve 122 connects the conduit 118 leading to pump
said cylinder devices at the same rate.
rnotor 44g to the reservoir 72, the purpose of this meter
3. Apparatus for elevating or lowering a substantially
ing valve being to bleed off part of the ?uid under pres
horizontal
platform comprising a base, a plurality of
sure supplied to the pump-motor 44g and prevent too fast 70
vertically-expandable hydraulic cylinder devices inter
a collapse of the cylinders 14a—14f. Relief valve 124
posed .at spaced points between the base and the platform,
serves to prevent an excessive build up of pressure in the
each of said hydraulic cylinder devices having the same
system and will open above a predetermined pressure to
volumetric capacity, hydraulic pumping means for supply
bypass ?uid to reservoir 72 through conduit 81.
The valve 120 will be closed by a cam 121 on the 75 ing ?uid under pressure to said hydraulic cylinder devices,
3,091,305
7
8
a plurality of hydraulic pump-motors each having an inlet
port adapted to be connected to said hydraulic pumping
lower said platform while maintaining the same in a
horizontal plane.
means, an outlet port for each pump-motor connected to
6‘. Apparatus for elevating or lowering a substantially
an associated one of said hydraulic cylinder devices, a
horizontal platform comprising a. base, a plurality of
separate hydraulic pump-motor having an inlet port
adapted to be connected to said hydraulic pumping means,
vertically-expandable hydraulic cylinder devices inter
posed vat spaced points between the base and the platform,
apparatus for mechanically interconnecting said plurality
of pump-motors with the separate pump-motor whereby
each of said hydraulic cylinder devices having the same
volumetric capacity, hydraulic pumping means for supply
each motor will be driven in synchronism with the others,
ing ?uid under pressure to said hydraulic cylinder devices,
valve means for selectively connecting said hydraulic 10 a plurality of hydraulic pump-motors each having an in
pumping means to either the inlet ports of said plurality
let port adapted to be connected to said hydraulic pumping
of pump-motors or the inlet ports of said separate pump
means, an outlet port for each pumpunotor connected
motor, the arrangement being such that when the valve
to an associated one of said hydraulic cylinder devices,
means connects the pumping means to the inlet ports of
gear means operatively connected to each pump-motor
the plurality of pump-motors ?uid under pressure will be 15 and adapted to be rotated by a flow of ?uid under pres
delivered to said cylinder devices at the same rate to ex
sure ‘between said inlet and outlet Ports, a separate hy
pand the same in synchronism and elevate said platform,
draulic pump-motor having an inlet port adapted to be
whereas when the valve means connects the pumping
connected to said hydraulic pumping means, an outlet
means to the inlet port of said separate pump-motor, the
port for the separate pump-motor, gear means opera
separate motor will cause the plurality of motors through 20 tively connected to said separate pump-motor and adapted
said mechanical interconnecting apparatus to expel ?uid
to be rotated by a ?ow of ?uid under pressure between
from the cylinder devices at the same rate to collapse the
the inlet and outlet ports, each of said plurality of hy
draulic pump-motors and said separate hydraulic pump
cylinder devices in synchronism and lower said platform.
motor being circumferentially spaced about a common
4. Apparatus for elevating or lowering a substantially
horizontal platform comprising a base, a plurality of 25 axis, gear means rotatable about said common axis and
vertically-expandable hydraulic cylinder devices inter
arranged to operatively engage the gear means of each
posed iat spaced points between the base and the platform,
hydraulic pumping means for supplying ?uid under pres
sure to said hydraulic cylinder devices, a plurality of
?uid metering devices each having an inlet port adapted 30
of said pump~motors whereby all of the pump-motors
to be connected to said hydraulic pumping means and
an outlet port connected to an associated one of said
will deliver ?uid under pressure at the same rate, and the
valve means for selectively connecting said hydraulic
pumping means to the inlet ports of said plurality of
pump-motors to cause each pump-motor to deliver ?uid
under pressure at the same rate to its associated hy
draulic cylinder to expand all of the cylinders in syn
hydraulic cylinder devices, means for controlling all of
chronism, said valve means being adapted to selectively
said metering devices whereby each metering device will
supply ?uid under pressure to its associated cylinder 35 connect said hydraulic pumping means to the inlet port
of said separate hydraulic pump-motor whereby the sep
device at a rate to cause all of the cylinder devices to
arate hydraulic pump-motor will drive the plurality of
expand in synchronism and maintain said platform in a
hydraulic motors to expel ?uid from all of said cylinders
horizontal plane, said means for controlling said metering
devices being adapted to cause ?uid to be dispelled from
‘at the same rate to retract the hydraulic cylinders in syn
the cylinder devices at rates such that the cylinder devices 40 chronism and lower said platform.
7. Apparatus for delivering ?uid under pressure at
will collapse in synchronism to lower said platform while
maintaining it in a horizontal plane.
5. Apparatus for elevating or lowering a substantially
the same rate to a plurality of hydraulic utilization de
vices comprising a plurality of hydraulic pump-motors
horizontal platform comprising a base, a plurality of
each having an input port adapted for connection to a
vertically-exp andable hydraulic cylinder devices interposed
45 source of hydraulic pressure, an output port for each
at spaced points between the base ‘and the platform, a
fluid reservoir, hydraulic pumping means for supplying
pump-motor connected to an associated one of said utiliza
tion devices, each of said hydraulic pump-motors being
?uid under pressure from said hydraulic reservoir to said
circumferentially spaced about a common axis, and gear
hydraulic cylinder devices, a plurality of hydraulic pump
idler means rotatable about said common axis and op
motors each having an inlet port adapted to be connected
to said hydraulic pumping means, an outlet port for each
pump-motor connected to an associated one of said hy
draulic cylinder devices, a separate hydraulic pump-motor
having an inlet port adapted to be connected to said hy
draulic pumping means, apparatus for mechanically con
necting said plurality of hydraulic motors with the sep
arate hydraulic motor whereby each motor will be driven
in synchronism with the others, and valve means for selec
tively connecting said hydraulic pumping means to the
inlet ports of said plurality of pump-motors while simul
taneously connecting the inlet port of said separate pump
eratively connected to each of said hydraulic pump-motors
to cause the pump-motors to operate in synchronism and
deliver ?uid at the same rate to said hydraulic utilization
devices.
8. Apparatus for delivering or expelling ?uid from a
plurality of hydraulic utilization devices at the same rate
comprising a source of ?uid under pressure, a plurality
of hydraulic pump-motors each having an inlet port
adapted to be connected to said ?uid pressure source,
an outlet port for each pump-motor connected to an
associated one of said hydraulic cylinder devices, gear
rality of pump-motors to the ?uid reservoir While con—
necting the inlet port of said separate pump-motor to
means operatively connected to each pump-motor and
adapted to be rotated by a ?ow of ?uid under pressure
between said inlet and outlet ports, a separate hydraulic
pump-motor having an inlet port adapted to be connected
to said ?uid pressure source, each of said plurality of
said hydraulic pumping means, the arrangement being
pump-motors and said separate pump-motor being cir
such that when the valve means connects the inlet ports
of the plurality of pump-motors to the pumping means
cumferentially spaced around a common axis, gear means
rotatable about said common axis and operatively con
motor to said ?uid reservoir, said valve means being
adapted to selectively connect the inlet ports of said plu
?uid under pressure will be delivered to each of said cylin
nected to the gear means of said hydraulic pump-motors
70 whereby the pump-motors will operate in synchronism to
vices in synchronism and elevate said platform, whereas
deliver ?uid at the same rate, and valve means for selec
when said valve mean-s connects the pumping means to
tively connecting said ?uid pressure source to the inlet
the inlet port of said separate pump-motor, the said sep
ports of said plurality of pump-motors whereby each
arate pump-motor will drive said plurality of motors to
pump~notor will deliver ?uid under pressure to its asso
expel ?uid from the cylinder devices at the same rate to 75 ciated hydraulic utilization device at the same rate, said
der devices at the same rate to expand said cylinder de
3,091,305
valve means being adapted to selectively connect the
hydraulic pumping means to the inlet port of said sepa
rate pump-motor whereby the separate pump-motor will
drive the plurality of hydraulic pump-motors through
said gear means to expel ?uid from said hydraulic utili
pump-motors to cause the same to operate in synchro
nism and deliver ?uid to said utilization devices at con
trolled rates.
References Cited in the ?le of this patent
zation devices at the same rate.
9. Apparatus for delivering ?uid under pressure to a
plurality of hydraulic utilization devices comprising a
plurality of hydraulic pump-motors each having an input
port adapted for connection to a source of hydraulic 10
pressure and an output port connected to an associated
one of said hydraulic utilization devices, and idler gear
10
means mechanically interconnecting all of said hydraulic
UNITED STATES PATENTS
2,291,578
2,343,912
2,481,047
2,888,299
2,947,148
Johnson _____________ __ July 28,
Lauck ______________ __ Mar. 14,
Sloane _______________ __ Sept. 6,
Balogh ______________ __ May 26,
Young _______________ __ Aug. 2,
1942
1944
1949
1959
1960
Документ
Категория
Без категории
Просмотров
0
Размер файла
968 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа