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Патент USA US3090323

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May 21, 1963
T. BUDZICH
3,090,313
VARIABLE DISPLACEMENT PUMP
Filed April 25, 1961
4 Sheets-Sheet 1
INVEN TOR.
May 21, 1963
T. BUDZICH
3,090,313
VARIABLE DISPLACEMENT PUMP
Filéd April 25, 1961
4 Sheets-Sheet 2
INVENTOR;
TADEUSZ 56/02/67,’
May 21, 1963
T. BUDZICH
3,090,313
VARIABLE DISPLACEMENT PUMP
Filed April '25, 1961
/8/
4 Sheets-Sheet 3
253
ATTO/QA/EYS
May 21, 1963
3,090,313
_‘ T. BUDZICH
VARIABLE DISPLACEMENT. PUMP
Filed April 25, 1961
4 Sheets-Sheet 4
A93
247
24.9
/43
/58
aa
/83
A519
A58
INVENTOR.
7:405u5z 5002/64
United States Patent 0
i
3,539,313
VARIABLE DlSi’LACEh/IENT PUMP
Tadeusz Bndzich, Shaker Heights, Ghio, assignor to The
Weatherhead Company, Cleveland, Ohio, a corporation
of Ohio
Filed Apr. 25, 196i, Ser. No. 105,357
9 Claims. (Cl. 103-37)
3',6'9’3;13'
1
ce
Patented May 21, 1983
2.
Another feature of this invention is that a manual con
trol for shifting the cylinder block may be supplied for
shifting the cylinder block in which the change in output
volume is directly proportional to the amount of move
ment of the cylinder block and hence of an external lever
which is provided for shifting the position of the cylinder
block.
,
Another feature of this invention is that no ?uid pres_
This invention relates generally to positive displacement
sure or spring forces are applied to the cylinder block
hydraulic pumps, and more particularly to the reciprocat 10 when ‘the dual manual control is employed so that the
ing piston type of positive displacement pumps in which
cylinder block remains easily shiftable by hand through
pistons are reciprocated through a ?xed stroke, but the
out both ranges of control and may be selectively
effective displacement of the pump can be varied to
clamped in position any place Within the ranges without
change the volume of the ?uid output.
producing noticeable stress on ‘any of the pump parts.
A principal feature of this invention is the provision 15
Another feature of this invention is that an automatic
of a positive displacement axial piston pump of the ?xed
control for the cylinder block is supplied in combination
stroke type in which the cylinder block is slidabie within
with a manual control in‘ which the automatic control
the pump housing and carries ports which permit ?uid
during manual operation will operate as an excess pres
within the pump housing to enter the cylinder bores, in
sure valve and shift the cylinder block to reduce the
which the effective volume of the pump is varied by
effective output volume in case the outlet pressure should
axially shifting the position of the cylinder block and
exceed a predetermined value even though the pump is
hence the ports relative to the piston stroke. For maxi
heing regulated by manual control.
mum output volume of the pump, the cylinder block is
Another feature of this invention is that in the afore
positioned so that the port is fully opened at the rear
described arrangement employing a combination auto
ward reversal of the piston to allow the cylinder bore to 25 matic and manual control, no force is normally applied
?ll with ?uid, after which forward motion of the piston
to the cylinder block in manual operation and the auto
seals off the port after only a short distance of movement.
matic control‘ is rendered inoperative and applies no
and forces the remainder of the ?uid Within the cylinder
forces to shift the cylinder block unless the outlet pres
bore out through check valves into the outlet port. By
sure should exceed the predetermined limit.
shifting the cylinder block in the one direction toward
Many additional features and vadvantages of this in
the forward end of the piston stroke, the port is not closed
vention relating to the simplicity of construction, ease of
by the piston until a later portion of the stroke, so that
operation and low cost of manufacture will readily be
some of the ?uid in the cylinder is forced back out
come apparent to those skilled in the art upon a reading
through the port and therefore a lesser volume is pumped
of the ‘following detailed description of several embodi
outward through the check valves. Pumps of this type 35 ments of the invention as illustrated in the drawings in
have been disclosed in co-pending applications by the
which:
present inventor Serial No. 825,005, ?led July 6, 1959
FIG. 1 is a longitudinal cross-sectional view of a pump
and Serial No. 847,512, ?led October 20, 1959.
according to the present invention in which the cylinder
According to the present invention, the cylinder block
block is shifted manually to control the effective output
may also be moved further toward the rearward end of
volume ‘by both spill type ‘control and throttling control;
the piston stroke so that the port is not completely opened
FIG. 2 is a fragmentary cross-sectional view of the
during the reversal of the piston and the ?uid Within the
cylinder block and piston when the cylinder block has
pump housing is throttled by the decreased size or" the
been shifted to minimum output volume employing the
port openings so that the cylinder ‘bore is not completely
throttling type control;
?lled and only that volume of ?uid which enters the cylin 45
FIG. 3 is a fragmentary cross-sectional view similar
der =bore is pumped out through the check valves. A
to that of FIG. 2 but showing the cylinder block shifted
pump incorporating this type of control is disclosed in
to the minimum effective volume position‘ according to
my co-pending application Serial No. 82,292, filed Janu
the spill type control;
my 12, 1961. In the present invention, both of these
PEG. 4 is an end elevational view of the pump of
types of control are incorporated into the same pump to 50 FIGS. 1—3 showing the external control lever;
provide two alternative methods of control for reducing
FIG. 5 is a side elevational view of the pump showing
the e?'eotive output volume of the pump.
the external control lever;
Another feature of this invention resulting from the
FIG. 6 is a longitudinal cross-sectional view of an
incorporation‘ in a single pump of both methods of con
other embodiment of the invention employing an internal
trol is that the position of the cylinder block can be con
automatic control for reducing the effective volume by the
trolled m-anually in such a manner that by employing the
spill type control and employing a manual control to re
spill type control, the cylinder block may be precisely
positioned over a relatively long range of movement to
provide very precise and accurate control of the output
volume, and the pump block can also be positioned by
the throttling type control to obtain a very rapid response
because of the short distance through which the cylinder
block moves to reduce the output volume with this
control.
Another feature of this invention resulting from the
dual methods of control of the effective output volume
of the pump is that an automatic control is supplied to
position the cylinder block using the spill type of control
while a manual control means is provided to shift the
cylinder block in the other direction to control the effec
tive output volume by the throttling of the ?uid entering
the cylinder bores.
duce the effective volume by throttling type control;
\FIG. 7 is a fragmentary cross-sectional view of the
pump of FIG. 6 showing the cylinder block shifted to
the minimum output volume according to the manual con
trol;
FIG. 8 is a fragmentary cross-sectional view similar to
that of FIG. 7 but showing the cylinder block shifted to
the minimum output volume by the automatic control; and
FIG. 9 is a side elevational view of the pump of FIGS.
6-8 showing the arrangement of the external control
lever.
Referring now to the drawings in greater detail, there
is illustrated in FIG. 1 a pump having a pump housing 10
which encloses a ?uid chamber 11 Within which the pump
mechanism is located. The pump housing 10‘ is generally
cylindrical in shape and at one end is formed with an in
3,090,313
3
4
.
ternal cylindrical end portion 12 which is closed off by
tantly about the cylinder block at points equidistant from
the axis of the drive shaft 35. Only one cylinder bore has
been shown for purposes of clarity, but it is understood
that the pump has a plurality of cylinders similar to the
one shown in the drawings and described hereinafter.
The cylinder block 62 is also provided with one or more
passages 67 extending therethrough from one side to the
other around the outer periphery and with a centrally dis
posed axial bore 68 so that ?uid can circulate freely
the side of pump housing 10 adjacent its mid-point for
connection to a ?uid reservoir for admission of ?uid l0 within the chamber ‘11 on both sides of the cylinder block.
A piston or plunger 70 is ?tted within the one end of
from the reservoir into the chamber (11.
the cylinder bores 65 and has a head portion 71 on the
At its other end, the pump housing \10 is closed o? by
end away from the wobble plate 55. Piston 70 has a
a drive housing 20 secured in place by means of cap
tubular skirt portion 72 extending rearwardly away from
screws 21. As shown, drive housing 20 is provided with
a radial ?ange 22 for mounting the pump in position on 15 the head portion 71. A compression spring 74 is ?tted
around the tubular skirt portion 72 and abuts at the one
machinery or a prime mover. An axial bore 24 extends
end against the web member 38. At the other end, com~
through the drive housing ‘20 to receive a bearing member
pression spring 74 abuts against a spring retainer 75 se
25 at its inner end. The bearing member 25 has an axial
cured at the outer end of the tubular skirt portion 72.
portion 26 extending along the bore 24 and a radial por
tion 27 extending outwardly along the inner wall of the 20 Thus the compression spring 74 serves to bias the piston
70 toward a rearward position within the cylinder bore
drive housing 20. A drive member 30 is rotatably jour
and toward the wobble plate 55. The piston 70 is driv
naled within the axial portion 26 of bearing member 25
ingly connected to the wobble plate 55 by means of a pis—
and has a shank portion 31 extending axially outward
ton rod 77 which is positioned within the tubular skirt por
through the drive housing to make sealing Contact with
oil seal '32 ?tted within the outer end of axial bore 25 tion 72. At its one end, piston rod 77 has a ball end 78
which seats in a suitable recess directly beneath the head
24. The drive member 30 has a radially extending ?ange
portion 71 on the piston 70, and at its other end the pis
portion 33 making bearing contact with the radial por
ton rod has another ball end 79 which is seated within a
tion 27 of the bearing member which provides a thrust
cup-like recess 81 on the face of the wobble plate 55.
bearing to absorb the axial forces of the pumping action.
A drive shaft 35 extends axially through a bore within the 30 At its midpoint the piston rod 77 is provided with a ra
dially extending ?ange or centering disc 82 to maintain the
drive member 30 and is secured thereto by a spline con
piston rod in axial alignment within the tubular skirt
nection 36. The drive shaft 35 projects axially outward
portion 72 if either end of the piston rod should become
beyond the end of the shank portion 31 for connection to
unseated from its seat against either the piston head 71
a suitable motor or other prime motor for driving the
35 or the wobble plate 55.
pump.
The cylinder block 62 has an annular groove or outer
Mid-way between the outlet housing 13' and drive hous
?lling slot 85 extending circumferentially about its pe
ing 20, a web member or plate 38 extends transversely
riphery and opening into each of the cylinder bores 65 to
across the ?uid chamber 11 and is provided with an
an outlet housing 13. The outlet housing 13 abuts
against an inwardly projecting ?ange 14 on the pump
housing 10- and is secured in place by means of suitable
set screws indicated at 15. An O-ring seal 16 is provided
on the outer periphery of the outlet housing 13 to prevent
leakage at the joint between the outlet housing and the
pump housing. A threaded inlet opening '18 is formed on
axially extending peripheral ?ange '39‘ which ?ts against
the walls of the pump housing 10-‘. The web memberS‘S
is held against axial movement by an inwardly extending
annular shoulder 40 formed on the pump housing 10, and
at the other end by a snap ring 41. The web member
38 has an axially extending portion 43‘ which projects to
ward the drive housing 20. The axial extension 43 is 45
provided with an axial bore 44 which communicates
with transverse opening 45 to allow free circulation of
?uid within the chamber 11 from one side of the web
member 38 to the other. The outer end of axial exten
sion 43 carries a bearing insert 46 which receives the pilot
end portion 47 of the drive shaft 3'5.
The drive member 38' is provided with an inclined face
50land a hub portion 51 which extends perpendicular to
the inclined face 50. A bearing member 52 is mounted
on drive member 30 and includes a radially extending 55
?ange portion 53 lying along the inclined ‘face 50, and
an axial sleeve portion 54 extending along the hub por
tion 51. Bearing member '52 serves to journal a wobble
plate 55 which is supported on the radial and axial hear
ing portions ‘53 and 54, respectively. At its lower end, 60
the wobble plate 55 is provided with a projecting stud 57
on which is rotatably secured a guide block 58. Guide
block '58 is adapted to slide longitudinally within a chan
nel 59 formed in the pump housing 10 to prevent rota
tion of the wobble plate 55 as it is oscillated by the rota
tion of the guide members 30.
V
A cylinder block 62 is slidably journaled in the cylin
drical end portion 12 of pump housing 10‘ for axial sliding
movement therein. The cylinder block 62 is restrained
from rotating Within the pump housing by a set screw 63
mounted in the wall of .the pump housing .10 and having,
a dog point engaging a longitudinal groove or guide slot
64 on the outer periphery of the cylinder block. The
cylinder block 62 is provided with a plurality of axially
extending cylinder bores 65 which are spaced equidis
admit ?uid therein.
A second annular groove or inner
?lling slot 87 extends radially outward from the axial
bore 68 within the cylinder block 62 to open into the
cylinder bores 65 at their inner sides. Forward edge 86
of the outer ?lling slot 85 and the forward edge 88 of the
inner ?lling slot 87 both lie in the same plane, and the
spacing of the forward edges 86 and 88 from the piston
head 71 determines the e?ective port area of the two
?lling slots 85 and 87.
A reaction piston 96 is slidably journalled within the
ends of the cylinder bores 65 opposite the pistons 70 to
make a sealing ?t within the cylinder bore to prevent leak
age of ?uid between the reaction piston and the cylinder
bore walls. Each of the reaction pistons 96 has an axial
bore 91 extending therethrough, and at the end away from
the piston 70, the reaction piston 96* has a snap ring 92
which forms one abutment for a compression spring 93
?tted around the end of the reaction piston. The other
end of compression spring 93 abut-s against a retainer plate
94 secured to the inner face of the outlet housing 13‘ by
suitable screws 96.
The outlet housing 13‘ is provided with a bore or cham
ber 98 opposite each of the reaction pistons 90‘ to receive
a port member 99. Port member 99 is provided with an
‘O-ring seal 101 to make sealing contact with the bore 98
and has a projecting end portion 102 to make sealing
contact with the end of the adjacent reaction piston 90.
A bore 103 extends through the port member 99‘ to con
nect with the axial bore 91 in the reaction piston 90. The
opposite end of the bore 98 is closed o? by a suitable
plug 104-, and positioned within the bore is a cage 106
which encloses a compression spring 107 biasing a check
valve plate 168‘ against the other end of the port member
99 to close off bore 103-. Thus the check valve plate 108
serves to permit ?uid within the reaction piston 98 and port
member 99 to pass outwardly past the plate, but prevents
?uid from entering the port member 99 from the outlet
5
3,090,313
side. A connecting passage 109 extends from each of the
bores 98 radially inward to connect with an wially located
outlet passage bore 111 in the outlet housing 13. Outlet
bore 111 is provided with a suitable threaded portion 112
at its outer end to receive a suitable pipe ?tting for con
nection to the outlet line of the pump.
The manual control mechanism for shifting the cylinder
block 62 longitudinally within the pump housing 1G is
shown most clearly in FIGS. 4 and 5 together with FIG.
1. The pump housing 10 includes a cross shaft housing 10
portion 115 projecting from the lower side of the pump
housing beneath the cylinder block 62. A cross shaft
117 is journaled in the cross shaft housing portion 115
and carries a lever arm 118 at its inner end. Lever arm
118 is secured to the inner end of the cross shaft 117
by a set screw 119 and at its upper end is provided with
an end portion 121 to ?t within the outer ?lling slot 85
on the cylinder block 62. It will be understood that the
end portion 121 ?ts into the outer ?lling slot '85 between
two of the cylinder bores so as not to block off or obstruct
the port area provided ‘by the ?lling slot at these cylinder
bores. An indicia plate 123 is mounted on projection
bosses 124 by means of suitable cap‘ screws 125 to extend
along the side wall of the pump housing 1%. A control
65
87 will never be open and no ?uid can enter the cylinder
bores. Thus the partial vacuum which occurs when the
piston is retracted will remain within the cylinder bore and
no fluid will be forced outward past the check valve
plate 108 when the piston is at the forward end of the
stroke and thus the pump will have no effective output
volume.
It will be understood that in accordance with the teach
ing of the inventor’s co-pending application Serial No.
82,292, previously referred to, that when the cylinder
block 62 is in a position intermediate that of FIGS. 1
and 2, where the forward edges 86 and 38 of the ?ll
ing slots are positioned closer to the piston head 71 when
the latter is in the retracted position, the effective port
area presented by the ?lling slots 85 and 87 will not be
sufficiently great to allow the ?uid within the pump hous
ing chamber 11 to completely ?ll the cylinder bores. The
reduced effective port area thus serves to throttle the
flow of ?uid into the cylinder bores to reduce that ?ow
to an amount less than that required to completely ?ll
the partial vacuum created within the cylinder bores by
the retraction of the piston. Only the volume of ?uid
which was permitted to enter by the position of the
ports will be pumped outward through the check valve
handle 127 is secured at its lower end to the outer end of 25
plate 193 ‘and only this amount will constitute the ef
the cross shaft 117 and extends along the inner side of in
fective output volume of the pump. Since it is neces
dicia plate 123. A screw clamp 130 is fastened to the
sary
to move the cylinder block 62 through only a very
upper end of control handle 127 to slide within an arcuate
short distance to change the effective output volume of
slot 128 on indicia plate 123. By tightening the screw
clamp 130, the control handle 127 can be locked in place 30 the pump from maximum to zero by this method of con
trol, a very fast response can be obtained.
on the indicia plate 123‘. It will be noted that a pointer
When the cylinder block 62 is shifted in the oppo
131 may be provided on the control handle 127 for
site direction away from the web member 33 and toward
alignment with indicia marks 132 along the arcuate upper
the outlet housing 13, it reaches a limiting position as
edge of indicia plate 123 for noting and recording the
relative position of the control handle with respect to the 35 shown in FIG. 3 in which the effective output volume
of the pump is also reduced to zero. As previously
indicia plate.
stated, when the piston 70 starts its ‘forward stroke, the
The operation of the pump can be seen most clearly in
?uid within the cylinder ibore will be spilled out through
conjunction with FIGS. 2 and 3. When the cylinder block
the ?lling slots S5 and 87 until the piston head 71 has
is in the position of FIG. 1 and the piston 7a is in the rear
passed to the forward edges ‘86 and 83 of the ?lling
ward or retracted position, the forward edges 86 and 818
slots to seal off these slots and prevent passage of ?uid
of the inner and outer ?lling slots 85 and 87, respectively,
‘from within the cylinder bore outward into the pump
are spaced forward of the piston head 71. Under these
housing chamber 11. As the cylinder block 62 is shifted
conditions, the ?uid within the chamber 11 is free to ?ow
toward the outlet housing 13, the piston 70‘ must move
inward through the ?lling slots to completely ?ll the
farther forward along its stroke before the ?lling slots
cylinder bore 65. As the piston 70: moves forward, the
85 and 87 are closed off. Thus, a lesser portion of the
piston head 71 will be shifted toward the reaction piston
piston stroke is employed for ‘forcing ?uid past the check
901 to reduce the volume within the cylinder. Since the
valve plate 1% and smaller volume of ?uid will there
?lling slots 85 and 87 are open during the initial portion
fore be discharged into the outlet passage bore 111 for
of the stroke, ?uid will be forced outward into the cham
ber 11 through these slots. However, after the piston head 50 each piston stroke. When the cylinder block ‘62 is shifted
to the limiting position of FIG. 3, the forward edges '86
71 passes the forward edges 86 and 88 of the ?lling slots,
and '88 of the filling slots 85 and 87, respectively, are
positioned on a line with the edge of the piston head
71 when the latter is at the forward end of its stroke.
Thus, the piston head 71 will never be able to close off
the ?lling slots ‘85 and 87 ‘before the end of the stroke
and all of the ?uid within the cylinder bores will be dis
charged outward through the ?lling slots and none will
108 will close and a partial vacuum will be formed with
be pumped outward past the check valve plates 198.
in the cylinder bores until the piston head 71 has retracted
past the forward edges 86 and 88‘ of the ?lling slots so 60
This latter method of controlling the pump volume re
that they are open to allow ?uid within the chamber 11
quires that the cylinder block 62 be shifted through a
to ?ow through the ?lling slots and re?ll the cylinder
distance equal to a substantial portion of the stroke of
bores.
the piston 70 to vary the effective output volume ‘from
The effective output volume of the pump may be re
maximum down to Zero. As a result, this method of
duced by two different methods, depending upon which
control allows the effective output volume to be very
direction the cylinder block is. shifted from the position
precisely controlled since the cylinder block 62 can be
of maximum output volume as shown in FIG. 1. When
positioned with a high degree of accuracy over the rela
the cylinder block is shifted toward the rearward position
tively long length of the control stroke. On the other
as shown in FIG. 2, the cylinder block as is brought into
hand, the response with this method will not be as ‘fast
contact with the web member 38. The ?lling slots 85' and
as that obtained with the throttling method since it nat
87 are hence moved toward the rearward position of the
urally will take more time to shift the cylinder block
these ?lling slots are sealed ed and the remainder of the
?uid within the cylinder bores will be positively displaced
outward through the reaction piston 9th and port member
99, and hence past the check valve plate 168, through
connecting passage 169', and into the outlet passage bore
111. When the piston 7 ti is retracted, the check valve plate
piston, and in the position shown, the forward edges 86 and
88 of the ?lling slot will be adjacent the head portion 71
of the piston when the latter is in the retracted position.
As a result, the ports provided by the ?lling slots 85 and 75
through the longer distance with this type control. Thus
the pump provides two methods of control, one employ
ing throttling control which requires that the cylinder
block be moved only a short distance to provide fast
3,090,313.
8
response, and the other employing spill control in which
a high degree of accuracy can ibe obtained because of the
relatively long length of movement of control handle.
It should be noted that there is no substantial resist
ance to a movement of the cylinder block 62 between
186 to serve as aport for admitting ?uid therein. A piston
185 is slidably mounted within the cylinder bore 188 and
has a head portion 136 extending forward within the cylin
der bore to a point adjacent the forward edge 134 of the
?lling slot 183. The piston 185 also has a tubular skirt
either of the limiting positions as shown in FIGS. 2 and
3. This is true because the design of the pump pro-v
portion 187 projecting rearwardly out of the cylinder bore
and toward the wobble plate 165. A compression spring
sorbed entirely by these members and will lie directly
along the axis of movement of the cylinder block. Thus
the only forces opposing the movement of the cylinder
block between these positions is the sliding friction of
the moving parts and the necessity of displacing the oil
portion 187. A piston rod 1192 is ?tted within the tubular
139 is ?tted around the tubular skirt portion 187 and abuts
vides that none of the pumping forces or reactive forces
at its one end against the web portion 151 of stop plate
are transmitted to the cylinder block itself. Since the
reaction piston 90 is of the same diameter as the pump 10 156. -At its other end, spring 189 abuts against a spring
retainer 196 secured to the outer end of tubular skirt
ing piston 79, the pumping reaction forces will be ab
from one side to the other of the cylinder block as it is
shifted within the chamber 11.
7 An alternative embodiment of the invention is shown
in FIGS. 6 through 9 in which the position of the cylin
der block is controlled by a manual and an automatic
control. The pump shown in these ?gures includes a
pump housing or body 140 which encloses a ?uid charn-V
her 141.
Fluid from a reservoir or other source ?lls
skirt portion 187 and at its one end carries a ball portion
193 which bears against the underside of the piston head
portion 186. The other end of piston rod 192 is formed
with another ball portion 194- and ?ts within a cup-like
recess 196 on the face of wobble plate 165. The mid
portion of piston rod 192 is enlarged as at 197 to maintain
the axial alignment of the piston rod 192 in case either of
the ends of the piston rod should be removed from their
respective sockets.
A reaction piston 200 is ?tted within the other end of
the cylinder bore 181) and extends toward the end plate
143.
The reaction piston 290 has an axial bore 201
therein to conduct ?uid from the cylinder bore to the
At the 25 pump outlet. At the end adjacent the end plate 143, reac
the chamber 141 through an inlet opening 14-2.
one end, pump housing 140 is closed off by an end plate
143 which is ?xedly secured to an outlet housing 144
by suitable locating pins indicated at 145. The end of
plate 143 has a tubular guide portion 147 extending axi
tion piston 200 is provided with a snap ring 282 which
serves as an abutment for a helical compression spring
203 which ?ts over the outer surface of the reaction
piston and abuts at its other end against the spring abut
ally into the chamber .141, and guide portion 147 has 30 ment plate 178. The outlet housing 144 has a recess 205
an axial bore 148 extending therein from the outer end.
in axial alignment with the cylinder bore to receive a
A stop plate 150 has a shank portion ?tted within axial
bore 148 and a radially extending web portion 151 ex
tending toward the walls of the pump housing 140.
At the other end of pump housing 140, an annular
bearing member ‘153 is mounted on the pump housing
port member 266. The port member 206 is provided with
inner end carries a pilot portion 153 which is journaled
prevent a reverse flow of ?uid from the recess 295 back
an O-ring seal 207 on its outer periphery to make sealing
contact with the recess 205 and has a projecting end 298
which extends out through an opening 259 in end plate
143 to make sealing contact with the end of the reaction
piston 20%. An axial bore 210 extends through a port
to journal a drive member 155. This drive member has
member 206 in alignment with the axial bore 201 in the
an axial ibore to receive a drive shaft 156 extending there
through and making a spline connection indicated at 4:0 reaction piston. A cage 212 is ?tted within recess 205 to
support a compression spring 213 which biases a check
157 to rotatably drive the drive member 155. The
valve plate 214 against the end of port member 206 to
drive shaft 156 extends into the chamber 14-1 and at its
within a bore on ‘the stop plate 150. The other end of
drive shaft 156 extends outward through a bore 169
in the Walls of pump housing 149 to make sealing con
tact with an‘oil seal 161 at the outer end of bore 160.
The drive member 155 carries an inclined annular bear
ing member 164 to rotatably journal a wobble plate 165.
In order to prevent the wobble plate 165 from rotating
within the pump housing .141} as it is oscillated by ro
tation of drive member 155, it is provided with a pro
jecting stud 167 at its lower end to rotatably journal
a bearing block 168. The bearing block 168 is made
a sliding ?t within a longitudinal channel or guide 169
formed on the walls of pump housing 140.
A cylinder block 175 is slidably mounted on a tubular
guide portion 147 for longitudinal movement withm the
into the reaction piston and cylinder bore. A connecting
passage 216 extends radially inward to connect to an
axially aligned outlet passage 218 formed in the outlet
housing 144. The outer end of outlet passage 218 is
threaded at 219 to receive a suitable pipe ?tting for the
outlet line from the pump.
The end plate 143 is provided with an axial extension
222 which extends into outlet passage 213 to seal off the
latter at the inner end. Leakage of the high pressure out
let ?uid past extension 222 is prevented by an O-ring seal
223 on its outer periphery. A reduced axial bore 224
extends through the extension 222 between outlet passage
218 and the axial bore or chamber 148 within the guide
portion 147. A valve spool 226 is slidably ?tted within
the axial bore 224 and has outer and inner reduced an~
nular portions 227 and 228 which de?ne ‘a land portion
229 between them. A passage 231 connects the outlet
passage 218 to the outer reduced annular portion 227,
tubular guide portion 147 to prevent rotation of the 60 and another passage 232 extends between the inner re
cylinder block within the pump housing. At its one end,
duced portion 228 and the chamber 141 within the pump
cylinder block 175 is limited in longitudinal movement
housing. An annular port 233 is formed on extension
by the web portion 151 of the stop plate 159. At the other
222 opposite the land 229 and is connected through
end, the cylinder block 175 is adapted to move into abut
passage 243 to chamber 148.
ment with a spring abutment plate 178 slidably jour
The inner end of valve spool 226 extends into the axial
naled within a cylindrical portion 179 of the pump hous-V
bore 148 and supports a cap 236. The cap 236 is pro—
purnp housing 140. The cylinder block 175 carries a
guide pin 176 to ?t within a longitudinal slot 177 on the
ing 140. A snap ring 181 is positioned within the cylin—
drical portion 179 to limit movement of the spring abut
vided with a socket on its inner face to receive a ball 237
which is also received in a spring abutment member 238.
ment plate 178 toward the stop plate ‘15%.
'
‘ The cylinder block 175 is provided with a plurality of 70 A control spring in the form of helical compression spring
longitudinal cylinder bores 189 extending from end to end
through the cylinder block and spaced equidistantly about
the axis of the drive shaft 156. An annular ?lling slot
183 extends circumferentially about the outer periphery
of cylinder block 175 and opens into the cylinder bores
239 extends longitudinally within the axial bore ‘1481 and
seats at its one end against the spring abutment 238 and
at its ‘other end against another abutment 241 which is
secured in the outer end of axial bore 148 by means of
a snap ring 242. Adjacent the spring abutment member
3,090,313
2.41, a radial passage 24:‘; extends outward through the
wall of tubular guide portion 147 to connect the axial
bore 143 with annular passage 246 formed in the cylinder
block 175 about the guide portion 147. In turn, annular
passage 246 connects with an axial cylinder bore 247
formed within the cylinder block 175 about tubular guide
portion 147. A piston 2418 is secured on the end of
tubular guide portion 147 by a snap ring 249 and makes
sealing contact with the walls of the axial cylinder bore
24-7 to form an expansible ?uid chamber 256- between the
cylinder block and the piston.
In order to provide an external control for shifting the
cylinder block 175, a control shaft housing 252 projects
downwardly below the pump housing 14%, and a trans
The automatic control operates to shift the cylinder
block 175 to reduce the effective output volume of the
pump whenever the pressure within the outlet passage
218 exceeds a predetermined level. When the pressure
in the outlet passage 218 is well ‘below this predetermined
level, the control spring 239 acting through abutment
238, ball 237 and cap 23-6 will bias the valve spool 226
in a leftward direction as shown in FIG. 6.
With the
valve spool 226 in this position, the land 229 is shifted
to the left of the annular port 233 which is then con
nected by the inner reduced annular portion 228 to the
drain passage 232 leading to the interior of the pump
housing. Since the annular port 233 is connected
through passage 243 to the axial bore 148, and the latter
verse control shaft 255 is journaled within housinng 252. 15
is in turn connected ‘through the radial passage 244 to the
A lever 254 is secured to control shaft 253 within the
chamber 259, this latter chamber will therefore be at
housing 252 and extends upward toward the cylinder
the low pressure corresponding to that of the fluid within
block 175 where it has a ball end 256 adapted to ?t within
the pump housing chamber 141. Thus the biasing vforce
the ?lling slot 183 on the cylinder block. A longitudinal
of the compression springs 203 on the reaction pistons
slot 257 is formed on the outer surface of cylinder block
29%
will bias the spring abutment plate 178 toward the
175 to allow lever 254 and ball end 256 to move freely
right and maintain the cylinder block 175 shifted in the
forward toward the spring abutment plate 1'78 so that the
position of FIG. 6 to insure that ‘the pump is operating
lever 254 can be rotated out of contact with the sides of
at maximum output volume, unless the operator through
the ?lling slot 183 when the pump is under automatic
the manual control lever should shift the cylinder rblock
control.
25 further toward vthe stop plate 156 to reduce the volume by
The control shaft 253 extends outward to the exterior
manual control.
of the pump, and as shown more clearly in FIG. 9, an
When the pressure within the outlet passage 21% builds
arm 259 is secured on the outer end of the shaft ad
up to the control pressure level, this pressure exerts a
jacent an indicia plate 261. A handle 262 is pivotally
mounted on the upper end of arm 259 by pivot pin 263, 30 ‘force on the end of the valve spool 2126 tending to shift it
toward the right as shown in FIG. 6 against the biasing
and a ‘torsion spring 264 it ?tted over the projecting end
force of the control spring 239. When this ‘biasing force
of pivot pin 263 and is connected both to a pin 266 on
of the fluid pressure is suf?ciently great to shift the valve
arm 259 and to another pin 267 on handle 262. Torsion
spool to a position where the land 229 is to the right of the
spring 264 provides a spring-loaded connection between
annular port 223, this latter port will be connected
the handle and arm and is positioned to normally bias
through the outer reduced annular portion 227 on the
the handle 262 into contact with a stop pin 268 on arm
valve spool to the passages 231 leading to the outlet
259. Thus, the handle and arm are normally in align
passages 21%}. Fluid under high pressure then enters
ment as indicated in FIG. 9 but force applied to the arm
through the passages 231, past the outer reduced annular
259 by rotation of ‘the control shaft 253 as the cylinder
block is moved toward the outlet housing under opera 40 portion 227 to the annular port 233, whence it ?ows
through passage 243 into the axial bore 148. From axial
tion of the automatic control will cause the handle 262
bore 148, the high pressure ?uid enters the chamber 250
in the operator’s hand to pivot around pivot pin 263
to expand the size of that chamber by shifting the cyl
against the force of torsion spring 264 to prevent pos
inder block 175 toward the outlet housing 144.
sible injury to the operator’s hand if he is holding the
As the cylinder block 175- is shifted, it moves the
handle 262 for shifting the cylinder block under manual
spring abutment plate 178 away from the snap ring stop
control when the automatic control comes into operation.
181 to compress the springs 263 on the reaction pistons.
The operation of this embodiment of the pump can be
The shifting of the cylinder block in this direction serves
seen more clearly in “conjunction with FIGS. 7 and 8.
to shift the forward edge 184 of the ?lling slot 183 closer
When the cylinder block 175 is in the intermediate
to the end of the reaction piston and to- the end of the
position as shown in ‘FIG. 6, the ?lling slot 183 will
compression stroke of the pistons 185. Thus the move
present a maximum port area at the rearward reversal
ment of the cylinder block in this direction through
of the piston so that the cylinder ‘bore will be completely
the operation of the automatic control reduces the ef
?lled at each reversal and all the fluid within the cylinder
fective output volume of the pump by the spill type
'bore corresponding to the displacement of the piston
control in a manner similar to the manual control in the
stroke will 'be pumped out through the reaction piston
embodiment of FIGS. 1 through 5.
~
269 and port member 2% to the outlet passage 218.
When the reduction in the effective output volume of
If the cylinder ‘block 175 is shifted by means of the
the pump serves to drop the pressure within outlet pas
manual control lever toward the stop plate 150, the for
sage 218 to the preselected value, the valve spool 226
ward edge 134 of ?lling 183 will be shifted ‘toward the
will ‘be shifted to the intermediate position of FIG. 6,
piston head 166“ to reduce the e?ective port area of the
where ‘the land 2219 Iblocks off the annular port 233 to
?lling slot. As has been previously described, the re
prevent further flow of fluid either into or out of the
duction in port area for the cylinder serves to throttle
chamber 251). It will be seen that the forces on the
the ?ow of ?uid into the cylinder bores and therefore
valve spool 226' tending to admit ?uid into the chamber
reduces the effective output volume of the pump toward
25% depend solely upon the pressure in the outlet pas
the zero output condition which occurs when the cyl
sage 218, While the forces tending to shift the valve spool
inder block is in the position of FIG. 7, so that the ?lling
226 toward the left to connect the chamber 250 with the
slot 183 is never uncovered by the piston head. It should
pump housing chamber 141 are the sum of the biasing
be noted that since the spring abutment plate 178 is
{force of the control spring 239‘, and the pressure within
limited in its range of movement by the snap ring 181,
the chamber 254) and axial bore 148 acting on the inner
there are no pumping or spring biasing forces exerted on
end of the valve spool 226, and these pressures will be
the cylinder block 175 when the latter is between the
dependent upon the amount of compression of the com
position shown in FIG. 6 and that shown in FIG. 7.
pression springs 293 biasing the cylinder block toward
Therefore, it requires no noticeable effort on the part
the maximum volume position.
of the operator to shift the cylinder ‘block within this
If, when the cylinder block 175 is shifted toward the
range by means of the manual control handle.
75 minimum output volume position as shown in FIG. 8,
3,090,313
11
with the cylinder block in the position where the piston
head 186 fails to’ cover the ?lling slot 183 to seal off the
intake port and hence no ?uid is pumped into the outlet
passage 218, an increase in demand at the outlet passage
218 will cause the pressure therein to decrease. The con
12
mounted for slidable movement within said fluid chamber
along a longitudinal axis, a plurality of cylinder bores in
said cylinder block, a piston within each of said cylinder
bores, means in said pump housing to progressively recip
rocate said pistons in said cylinder bores between forward
and retracted positions, means connecting each of said
cylinder bores to said outlet port, an inlet port for each
trol mechanism will therefore act to shift the cylinder
block back toward the maximum position to increase the
cylinder bore in said cylinder block, said port having axi
output volume of the pump to maintain the selected pres
ally spaced edges, said cylinder block de?ning a maximum
sure in the following manner. Decrease in the pressure
at the outlet, passage 218 will cause the valve spool 10 volume position when the piston head is intermediate
said port edges when the piston is in the retracted posi
tion, means to shift said cylinder block in one direction
said forces of the control spring 239 and the ?uid pressure
from said maximum volume position to reduce the effec
Within chamber 259. The land 229 will then be shifted
tive area of said cylinder bore inlet ports, and means to
to the left of the annular port 223, and the axial bore 148
shift said cylinder block in the other direction from said
and chamber 250 will then be connected to the pump
maximum volume position to reduce the effective length
housing chamber 141 in the aforedescribed manner. The
of the pumping stroke of the pistons.
biasing force of the compression spring 203 will then tend
2. A pump comprising a pump housing providing a
to shift the spring abutment plate 178 and cylinder block
?uid chamber therein, an inlet port to said ?uid chamber,
175 toward the right and force the ?uid within chamber
an outlet port on said pump housing, a cylinder block
250 out into axial bore 148 and hence past the valve
mounted for slidable movement within said ?uid chamber
spool 226 into the pump housing chamber 141. This ac
along a longitudinal axis, a plurality of cylinder bores in
tion will continue until either the cylinder block 175 has
said cylinder block, a piston within each of said cylinder
been shifted back to the maximum volume position where
bores, means in said pump housing to progressively recip
the spring abutment plate 178 is in contact with the snap
ring stop 181, or else the pressure within the outlet pas 25 rocate said pistons in said cylinder bores between forward
and retracted positions, means connecting each of said
sage 218 rises to a point where the valve spool 226 is
cylinder bores to said outlet port, an inlet port for each
shifted back toward the right so that land 229 blocks off
cylinder bore in :said cylinder block, said port having axi
the annular port 233.
ally spaced edges, said ‘cylinder block de?ning a maximum
“If the pump is in operation under manual control with
volume position when the piston head is intermediate said
the operating handle 262 moved to shift the cylinder block
port edges when the piston is in the retracted position,
175 to a position where it is intermediate the spring abut
226 to be shifted toward the left as a result of the afore
ment plate 178 and the stop plate 150, and the pressure
within the outlet passage 218 should exceed the auto
matic control level, the valve spool 226 will be shifted
in to admit ?uid into chamber 250 and thereby force the
cylinder block 175 past the maximum volume position
toward a reduced volume position within the spill control
range.
Thus the automatic control serves as a pressure
overload protective device to prevent the operator from
exceeding the maximum pressure for the system when he
is operating the pump under manual control. When it is
intended to operate the pump using automatic control, the
control handle 262 will be shifted to the lefthand position
as seen inFIG. 9, so that the ball end 256 on lever 254 is
shifted toward the end of the longitudinal slot 257 adja_
cent the spring abutment plate 178. This insures that
position of the cylinder block 175 under the automatic
control will not impart any motion to the lever 254 and
hence to the operating handle 262. However, if the han
dle should be left in the righthand position as shown in
FIG. 9, and if the automatic control should take over to
shift the cylinder block 175 toward the left, the motion
of the cylinder block 175 will force the lever 254 to the
left, since the forces of the pressure within the chamber
250 biasing the cylinder block in that direction are rela
tively high compared to the forces which can be applied
to the cylinder block by hand. If the operator is holding
the handle 262 under these conditions, the rotation of the
manual control means on the exterior of said pump hous
ing adapted to shift said cylinder block along said longi
tudinal axis, said manual control means being operable
to, shift said cylinder block in one direction from said
maximum volume position to reduce the effective area of
said cylinder bore inlet ports, said manual control means
being operable to shift said cylinder block in the other
direction from said maximum volume position to reduce
the effective length of the pumping stroke of the pistons.
3. A pump comprising a pump housing providing a
?uid chamber therein, an inlet port to said ?uid chamber,
an outlet port on said pump housing, a cylinder block
mounted for slidable movement within said ?uid chamber
along a longitudinal axis, a plurality of cylinder bores in
said cylinder block, a piston Within each of said cylinder
bores, means in said pump housing to progressively recip
rocate said pistons in said cylinder ‘bores between for
ward and retracted positions, check valve means connect
ing each of said cylinder bores to said outlet port, an inlet
port for each cylinder bore in said cylinder block, said
port having axially spaced edges, said cylinder block de
?ning a maximum volume position when the piston head
is intermediate said port edges when the piston is in
the retracted position, manual control means to shift said
cylinder block in one direction from‘ said maximum vol
ume position to reduce the effective area of said cylinder
bore inlet ports, and control means responsive to ?uid
pressure in said outlet port to shift said cylinder block in
the other direction from said maximum volume position
control shaft 253 and hence arm 259 will cause the toggle
joints between the arm and handle to break against the
to reduce the effective length of the pumping stroke of the
biasing force of torsion spring 254 and the control shaft
pistons.
253 will be able to rotate without movement of the handle
4. A pump comprising a pump housing providing a
262 and the latter will not be forced from the operator’s
?uid chamber therein, an inlet port to said ?uid chamber,
hand in a manner which could cause serious injury.
While several embodiments of the invention have been 65 an outlet port on said pump housing, a cylinder block
mounted for slidable movement Within said ?uid chamber
shown in the drawings and described hereinabove in con
along a longitudinal axis, a plurality of cylinder bores ex
siderable detail, it ‘is understood that this invention can
tending axially through said cylinder block, a piston with
take many other forms and embodiments, and that such
in one end of each of said cylinder bores, wobble plate
forms and embodiments as may occur to those skilled in
the art may be resorted to without departing from the 70 means in said pump housing to progressively reciprocate
said pistons in said cylinder bores between forward and
scope of the invention as de?ned in the following claims.
retracted positions, a tubular reaction piston within the
What is claimed is:
other end of each of said cylinder bores, said reaction pis
1. A pump comprising a pump housing providing a
tons having the same diameter as said pistons, check valve
?uid chamber therein, an inlet port to said ?uid chamber,
an outlet port on said pump housing, a cylinder block 75 means on said pump housing adjacent each of said tubular
3,090,313
13
reaction pistons, means connecting each of said check
valve means to said outlet port, an inlet port for each
cylinder bore in said cylinder block, said port having
axially spaced edges, said cylinder block de?ning a maxi
mum volume position when the piston head is intermedi
ate said port edges when the piston is in the retracted
position, means to shift said cylinder block in one direc- '
14
drive means in said pump housing to progressively re
ciprocate said pistons in said cylinder bores between for
Ward and retracted positions, a tubular reaction piston
within the other ends of each of said cylinder bores, said
reaction pistons having the same diameter as said pistons
and being axially slidable relative to said cylinder block
and said pump housing, check valve means on said pump
tion from said maximum volume position to reduce the
housing adjacent each of said tubular reaction pistons,
effective area of said cylinder bore inlet ports, and means
spring means maintaining said reaction piston in sealing
to shift said cylinder block in the other direction from 10 engagement with said check valve means, means connect
said maximum volume position to reduce the effective
ing each of said check valve means to said outlet port, an
length of the pumping stroke of the pistons.
inlet port for each cylinder bore in said cylinder block
5. A pump comprising a pump housing providing a
adjacent the head of the piston therein when the piston is
?uid chamber therein, an inlet port to said ?uid chamber,
in the retracted position, manual means to shift said cyl
an outlet port on said pump housing, a cylinder block 15 inder block in one direction to reduce the effective area
mounted for slidable movement within said ?uid cham
of said cylinder bore inlet ports, and control means re
ber along a longitudinal axis, a plurality of cylinder bores
sponsive to ?uid pressure in said outlet port to shift said
extending axially through said cylinder block, a piston
cylinder block in the other direction to reduce the effective
within one end of each of said cylinder bores, wobble
length of the pumping stroke of the piston.
'
plate means in said pump housing to progressively recip
8. .A pump comprising va pump housing providing a
rocate said pistons in said cylinder bores between forward
generally cylindrical ?uid chamber therein, an inlet port
and retracted positions, a tubular reaction piston within
to said ?uid chamber, an outlet port on said pump hous
the other end of each of said cylinder bores, said reaction
ing, a cylinder block slidably journaled in said pump hous
pistons having the same diameter as said pistons, check
ing for longitudinal movement therein, guide means pre
valve means on said pump housing adjacent each of said 25 venting rotation of said cylinder block in said pump
tubular reaction pistons, passage means connecting each of
housing, a plurality of cylinder bores extending axially
said check valve means to said outlet port, an inlet port
through said cylinder block, a piston within one end of
for each cylinder bore in said cylinder block, said port
each of said cylinder bores, wobble plate drive means in
having axially spaced edges, said cylinder block de?ning
said pump housing to progressively reciprocate said pis
a maximum volume position when the piston head is inter
mediate said port edges when the piston is in the retracted
tons in said cylinder bores between forward and retracted
positions, a tubular reaction piston within the other end
position, manual control means on the exterior of said
of each of said cylinder bores, said reaction pistons hav
pump housing operable to shift said cylinder block along
ing the same diameter as said pistons and being axially
said longitudinal axis, said manual control means being
slidable relative to said cylinder block and said pump
operable to shift said cylinder block in one direction from 35 housing, check valve means on said pump housing ad
said maximum volume position to reduce the effective
area of said cylinder bore inlet ports, said manual con
trol means being operable to shift said cylinder block in
the other direction from said maximum volume position
to reduce the effective length of the pumping stroke of the
pistons.
6. A pump comprising a pump housing providing a
?uid chamber therein, an inlet port to said ?uid chamber,
an outlet port on said pump housing, a cylinder block
mounted for slidable movement within said ?uid chamber
along a longitudinal axis, a plurality of cylinder bores
extending axially through said cylinder block, a piston
jacenteach of said tubular reaction pistons, spring means
maintaining said reaction pistons in sealing engagement
with said check valve means, passage means connecting
each of said check valve means to said outlet port, an
inlet port for each cylinder bore in said cylinder block,
said port having axially spaced edges, said cylinder block
de?ning a maximum volume position when the piston
head is intermediate said port edges when the piston is in
the retracted position, manual control means on the ex
iterior of said pump housing operable to shift said cyl
inder block longitudinally within said pump housing, said
manual control means being operable to shift said cyl
inder ‘block in one direction from said maximum volume
position to reduce the effective area of said cylinder bore
inlet ports, said manual control means being operable to
shift said cylinder block in the other direction from said
ward and retracted positions, a tubular reaction piston
maximum volume position to reduce the effective length of
within the other end of each of said cylinder bores, said
the pumping stroke of the pistons.
reaction pistons having a diameter equal to the diameter
9. A pump comprising a pump housing providing a fluid
of said pistons, check valve means on said pump housing
adjacent each of said tubular reaction pistons, passage 55 chamber therein, an inlet port to said fluid chamber, an
outlet port on said pump housing, a cylinder block
means connecting said check valve means to said outlet
mounted for slidable movement within said ?uid chamber
port, an inlet port for each cylinder bore in said cylinder
along a longitudinal axis, a plurality of cylinder bores ex
block adjacent the head of the piston therein when the
tending axially through said cylinder block, a piston With
piston is in the retracted position, manual control means
in one end of each of said cylinder bores, wobble plate
on said pump housing operable to shift said cylinder block
drive means in said pump housing to progressively re
in one direction to reduce the effective area of said
ciprocate said pistons in said cylinder bores, a tubular re
cylinder bore inlet ports, and control means responsive to
action piston within the other end of each of said cylinder
?uid pressure in said outlet port to shift said cylinder
bores, said reaction piston having the same diameter as
block in the other direction to reduce the effective length
within one end of each of said cylinder bores, wobble
plate means in said pump housing to progressively recip
rocate said pistons in said cylinder bores between the for
of the pumping stroke of the pistons.
7. A pump comprising a pump housing providing a
generally cylindrical fluid chamber therein, and inlet port
said piston and being axially slidable relative to said
cylinder block and said pump housing, check valve means
on said pump housing adjacent each of said tubular re
to said ?uid chamber, an outlet port on said pump hous
action pistons, spring means maintaining said reaction
tending axially through said cylinder block, a piston with
position when the piston head is intermediate said port
ing, a guide member secured to said pump housing and 70 pistons in sealing engagement with said check valve means,
passage means interconnecting said check valve means
extending longitudinally coaxial with said ?uid chamber,
and said outlet port, an inlet port for each cylinder bore
a cylinder block mounted for axially slidable movement
in said cylinder block, said port having axially spaced
on said guide member, a plurality of cylinder bores ex
edges, said cylinder block de?ning a maximum volume
in one end of each of said cylinder bores, wobble plate 75 edges when the piston is in the retracted position, a rocker
3,090,313
15
shaft in said pump housing extending transversely to said
longitudinal axis, means interconnecting said rocker shaft
and said cylinder block whereby rotation of said ‘rocker
shaft moves said cylinder block axially, lever means ex
teriorly of said pump housing for rotating said rocker
shaft, whereby movement of said control lever in one
direction from the maximum position with respect to said
pump housing shifts the position of said cylinder block
to reduce the effective output volume of the pump by
l6
duce the effective output volume of the pump by reducing
the e?ective inlet port area.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,041,422
2,369,134
2,990,781
Tuck et al _____________ __ July 4, 1961
402,603
Great Britain ________ __ Dec. 7, 1933
decreasing the effective ‘length of the stroke of said pistons, l0
and movement of said lever in the other direction from
said maximum position shifts said cylinder block to re
'
L’Orange ____________ .__ May 19, 1936
Cameron ______ _,_ ____ __ Feb. 13, 1945
FOREIGN PATENTS
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