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Патент USA US3035620

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May 22, 1962
R. E. PRUNTY
3,035,610
CONTROL VALVE FOR HYDRAULIC ACTUATOR
Filed Sept. 10, 1959
2 Sheets-Sheet 1
"/-4-
IN VEN TOR.
May 22, 1962
R. E. PRUNTY
3,035,610
CONTROL ‘VALVE FOR HYDRAULIC ACTUATOR
Filed Sept. 10, 1959
2 Sheets-Sheet 2
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E INVEN TOR.
United States Patent 0 "cc
1
3 035,610
CONTROL VALVE FOlR HYDRAULIC ACTUATOR
Robert E. Prunty, Charles City, Iowa, assignor, by mesne
assignments, to Oliver Corporation, Chicago, 111., a
corporation of Delaware (1960 corporation)
Filed Sept. 10, 1959, Ser. No. 839,122
4 Claims. (Cl. 137-621)
3,035,610
Patented May 22, 1952
2
A passage 34 opening to the outside of valve body 10
is provided therein and forms an inlet-outlet passage
adapted to be connected to the cylinder of a single acting
hydraulic actuator under load.
A passage 36 is provided in valve body 10 to connect
bores 12 and 18. The passage 36 bypasses bore 20. A
passage 38 is provided in valve body 10 adjacent passage
34 and has an open end thereof plugged by a threaded
plug 40. A passage 42 is provided to connect passage
38 and bore 12, which are also connected by another
smaller passage 44 which bypasses bore 20 and has a
restrictive ori?ce 46 adjacent passage 38. ‘The passage
acting piston under load.
32% is also connected to bore 20 by a passage 48 and
In the past, a close ?t between the valve body and
to bore 22 by a passage 50 which bypasses bore 12. A
the lands on a spool of a control valve was relied upon 15 passage 52 connects the inner end of bore 20 with pas
to maintain a load in a raised position in the neutral
sage 42.
position of the control valve. It has been found that
A passage 54 intersects bore 12 adjacent the end
This invention relates generally to control valves for
hydraulic actuators, and particularly to a control valve
for use in a hydraulic power system including a pump,
a reservoir, and a hydraulic actuator having a single
such valves have short lives, especially under conditions
leading ‘to the reservoir and angles through valve body
conducive to contamination of the hydraulic ?uid, and
10, bypassing passage 38 and intersecting a passage 56
in addition, they are expensive to manufacture, involv 20 having an open end plugged by a plug 58. A passage
60 is provided in valve body 10 to connect passage 56
ing close tolerances, super ?nishes, selective assembly,
with passages 34 and 38.
It is an object of the invention to provide an improved
‘The plug 58 is recessed at its inner end to receive a
control valve.
compression spring 62 which urges a ball check valve
Another object of the invention is to provide a con 25 64 toward an annular seat 66 provided in passage 56.
trol valve which has a longer life and is less costly to
Similarly, the plug 40 is recessed at its inner end to re
manufacture than former control valves.
ceive a compression spring 68 which urges a ball check
A further object of the invention is to provide a con
valve 70 toward an annular seat 72 provided in passage
trol valve for a hydraulic actuator having a single acting
33. The passage 42 is provided with an annular check
piston under load, in which a separate lowering valve 30 valve seat 74 engageable by a ball check valve 76 urged
spool is provided which is isolated from return ?ow from
toward seat 74 by a compression spring 78.
etc.
the actuator so as to be less subject to Wear.
A still further object of the invention is to provide
a control valve for a hydraulic actuator having a single
A bore is provided in valve body 10 between the inner
end of bore 18 and passage 56 for mounting a plunger
80 by which ball check valve 64 may be operated. The
acting piston under load, in which maintaining of the “ inner end of bore 18 is provided with a vent passage 82
load in position is not dependent upon the closeness of
forming an outlet passage adapted to be connected to
?t between a bore in the body of the control valve and
the reservoir. The outer end of bore 18 is adapted to
a valve spool therein.
receive a retaining ring 84 for maintaining a plug 86 in
These and other objects will appear from time to time
bore 18. The plug 86 is centrally grooved to receive
as the following speci?cation proceeds and with refer 40 O-ring seal 88. A compression spring 90 is provided at
ence to the accompanying drawings wherein:
the inner end of bore 18 for urging lowering valve spool
FIGURE 1 is a schematic sectional view of the con
24 toward plug 36. The lowering valve spool 24 is hol~
trol valve or" the invention, showing the neutral position
low and open at the end thereof adjacent plug 86. Ports
92 at the open end of spool 24 connect the hollow inte
thereof;
FIGURE 2 is a partial schematic view of the control 45 rior thereof with bore 18 and passage 36.
valve in load raising position;
The outer end of bore 20 also forms an outlet passage
FIGURE 3 is a partial schematic view of the control
adapted to be connected to the reservoir, but is provided
valve in load lowering position; and
with an annular member 94 threaded into valve body
FEGURE 4 is a schematic diagram of the system,
10 to provide a seat for a compression spring 96 which
wherein V is the control valve, P is the pump, R is the 50 urges vent valve spool 26 inwardly. Vent valve spool
reservoir, -A is the hydraulic actuator, and L is the
26 is hollow and open at its outer end. Lands 100 and
load.
In FIGURE 1, a valve body 10 is shown in section.
A bore 12 therein is provided to receive a main control
1112 thereon de?ne an annular groove 104 which is con
nected to the hollow interior of spool 26 by ports 98.
The outer end of bore 22 is plugged by a plug 106
valve spool 14 operable from an end 16 thereof project 55 threaded into valve body 10 and providing a seat for a
ing from the body 10. Bores 18, 29, and 22 are also
compression spring 108 which urges flow control valve
provided in valve body 10 to receive a lowering valve
spool 28 inwardly. A land 110 is provided on spool
spool 24, a vent valve spool 26, and a ?ow control valve
28 to cooperate with the inner end of bore 22 between
spool 28, respectively.
passages 30 and 32.
The main control valve spool 14 is provided with a
An inlet passage 30 opening to the outside of valve 60
body 10 is provided therein and forms a pressure pas
plurality of lands and grooves, including lands 112, 114,
sage adapted to be connected in a suitable manner to
the outlet of a pump (not shown) of the constant dis
116, 113, 120, and 122. The spool 14 is hollow and
open at the end thereof opposite end 16. Ports 124
placement type. Passage 30 intersects bores 12 and 22
adjacent land 112 and ports 126 between lands 118 and
as shown. A passage 32 opening to the outside of valve 65 121} connect the outside or" spool 14 with the hollow inte
rior thereof.
body 10 is provided therein and forms an outlet passage
adapted to be connected to the reservoir (not shown)
The neutral position is shown in FIGURE 1. In this
for the pump. The passage 32 intersects bore 22 as
position, ?uid from the pump directed to pressure pas
shown. The end of bore 12 opposite the end from
sage 31) may flow around spool 14 in bore 12, through
which end 16 of main control valve spool 14 projects 70 passage 44, ori?ce 46, passage 38, passage 48, and ports
opens to the outside of valve body 10 and forms an
93, and through the hollow interior of spool 26 and
outlet passage adapted to be connected to the reservoir.
member 94 to the reservoir. In this flow path, ori?ce
3,085,810
3
4
46 presents the greatest resistance to flow, so that the
36 through ports 124 and the interior of spool 14 to
the reservoir is blocked by lands 112 and 114, and a
portion of the ?uid delivered to passage 30 by the pump
will ‘?ow around spool 14 to passage 36 and into the
interior of lowering valve spool 24 through ports 92
(FIGURE 1). The ?uid pressure will move lowering
valve spool 24 to the position shown in FIGURE 3
against the force of spring 90. The spool 24 will shift
plunger 80 to unseat ball check valve 64, and ?uid from
pressure downstream thereof is substantially atmospheric.
Therefore the pressure in passage ‘50, and in here 22 be
tween ?ow control valve spool 28 and plug 106, is also
very nearly atmospheric in this neutral position of the
valve, and ?uid in pressure passage 30 moves the valve
spool 28 outwardly against the force of spring 108 to
the position shown, allowing the greater portion of the
?uid supplied to passage 30 by the pump to flow back
to the reservoir through passage 32'.
Flow from pas
sage 30 to passage 42 is blocked by land 116, and ?ow
from passage 30 to passage 36 is blocked by land 114
the cylinder of the hydraulic actuator will ?ow under
pressure of the load through passages 34 and 60, check
valve seat 66, passage 56, passage 54, and bore 12 to the
reservoir.
If a throttled lowering of the load is desired, the
spool 14 may be moved only part way from the position
of FIGURE 1 to the position of FIGURE 3, so that land
122 barely uncovers passage 54 and the ?ow from pas
and open to the reservoir through ports 126 and the
hollow interior of spool 14.
sage 54 to bore 12 and the reservoir is throttled by land
122.
' In FIGURE 2, the valve is shown in load raising posi
tion, main control valve spool 14 having been shifted 20 The main control valve spool 14 acts as a pilot valve
with respect to vent valve spool 26 and lowering valve
to the right from the neutral position. In this position,
spool 24, but directly controls ?ow to the hydraulic
passage 42 is not blocked by land 116, so that ?uid from
actuator for the raising of the load. The provision of
the pump directed to pressure passage 30 may ?ow
separate lowering valve spool 24 and ball check valve
around spool 14 in bore 12, through passage 42 and check
64 operated thereby renders the maintaining of the load
valve seat 74, through passage 38 and check valve seat
on the actuator in a given position entirely free of the
72, and out passage 34 to the cylinder of the hydraulic
closeness of ?t between bore 12 and spool 14. Greatly
actuator. The pressure in passage 42 acts through pas
increased valve life has resulted, along with lower manu
sage 52 to move vent valve spool 26 to the left in bore
facturing costs, greater interchangeability of parts, etc.
20 to the position shown. In this position of spool 26,
flow through passage 44, ori?ce 46, passage 38, and 30 Variations and modi?cations may be made without de
parting from the spirit and scope of the invention.
passage 48, to groove 104, ports 98, the interior of spool
The invention is claimed as follows:
26, and the reservoir, is blocked by land 100 on spool
1. A control valve for a hydraulic actuator compris
26, so that passage 50 is no longer vented. Substantially
ing a valve body, a ?rst bore in said valve body, a main
full pump pressure then exists at both ends of ?ow con
trol valve spool 28, and spring 108 acts to move spool 35 control valve spool in said ?rst bore, an inlet passage
in said valve body communicating with said ?rst bore
28 to the position shown, wherein passage 32 to the
and adapted to be connected to a pump, an outlet pas
reservoir is blocked from passage 30 by land 110, and
sage in said valve body adapted to be connected to a
full pump delivery goes to the cylinder of the hydraulic
reservoir, an inlet-outlet passage in said valve body
actuator. Flow from passage 30 to passage 36 is blocked
by lands 112 and 114 of spool 14, and passages 36 and 40 adapted to be connected to a hydraulic actuator, ?rst
passage means in said valve body connecting said ?rst
54 are open to the reservoir through ports 124 and 126,
bore and said inlet-outlet passage, second passage means
respectively, and the interior of spool 14.
in said valve body separate from said ?rst passage means
If the main control valve spool 14 is only moved part
and connecting said inlet-outlet passage and said outlet
way from the position of FIGURE 1 to the position of
FIGURE 2, the land 116 may be made to barely un 45 passage, a check valve in said second passage means
connecting said inlet-outlet passage and said outlet pas
cover passage 42, so that a considerable pressure drop
sage normally preventing ?ow of ?uid from said inlet
may be made to occur across land 116. ' Less than full
outlet passage to said outlet passage, a second bore in
pump pressure will exist then in passages 42, 38, and 50,
said valve body, a lowering valve spool in said second
and at the right end of spool 28 in bore 22, and spool
28 will assume a position between the limits shown in 50 bore, third passage means in said valve body separate
from said ?rst and second passage means and connecting
FIGURE 1 and FIGURE 2, so' that part of the pump
said ?rst and second bores, check valve operating means
delivery will go to the cylinder of the hydraulic actuator
in said valve body operable by said lowering valve spool
to produce a throttled raise of the load, and the remainder
to open said check valve, means on said main control
of the pump delivery will be returned to the reservoir
55 valve spool for controlling ?ow of ?uid from said ?rst
through passage 32.
r
bore through said ?rst passage means to said inlet-outlet
In FIGURE 3, the valve is shown in load lowering
passage, reverse ?ow preventing means in said ?rst pas—
position, main control valve spool 14 having been shifted
sage means, means on said main control valve spool for
to the left from the neutral position of FIGURE 1. In
controlling ?ow of ?uid through said third passage means
this‘ position, ?ow from passage 30 to passage 42 and
connecting said ?rst and second bores for operating said
the cylinder is blocked by lands 116 and 118, and pas
lowering valve spool, and means providing a ?uid by
sage 42 is open to the reservoir through ports 126 and
pass between said inlet passage and the reservoir when
the hollow interior of spool 14. With no pressure in
?uid is not ?owing from said ?rst bore to said inlet-outlet
the right end of bore 20, spool 26 will assume the posi
passage.
tion shown under the in?uence of spring 96, and passage
2. A control valve for a hydraulic actuator compris
48' will be unblocked. Fluid may ?ow vfrom pressure
ing a valve body, a ?rst bore in said valve body having
passage 30 through passage 44, ori?ce 46, passage 38,
an end forming an outlet passage adapted to be connected
passage 48, groove 104, ports 98, and the hollow interior
of spool 26 to the reservoir. The right end of bore 22
to a reservoir, a main control valve spool in said ?rst
will also be open to the reservoir through passages 50,
bore, an inlet passage in said valve body communicating
38, 48, groove 104, ports 93, and the interior of spool 70 with said ?rst bore and adapted to be' connected to a
26. Pressure on the left end of spool 28 will then act
pump, an inlet-outlet passage in said valve body adapted
against spring 108 and cause spool 28 to assume the posi
to be connected to a hydraulic actuator, ?rst passage
means in said valve body connecting said ?rst bore and
tion shown, in which the greater portion of the ?uid
supplied to passage 30 by the pump will ?ow back to
said inlet-outlet passage, second passage means in said
the reservoir through passage 32. Flow from passage
valve body separate from said ?rst passage means and
in the neutral position of the valve, passage 36 being
slightly uncovered by land 112 and open to the reservoir
through ports 124 and the hollow interior of spool 14,
and passage 42 being slightly uncovered by land 113
3,035,810
6
connecting said inlet-outlet passage and said outlet pas
bore, a passage in said valve body communicating at
sage, a check valve in said second passage means connect
one end with said ?rst bore and continuously open to
said inlet passage around said main control valve spool
and having a ?xed ori?ce adjacent the other end in com
ing said inlet-outlet passage and said outlet passage nor
mally preventing ?ow of ?uid from said inlet-outlet pas
sage to said outlet passage, a second bore in said valve
body, a lowering valve spool in said second bore, third
munication with said passage means from said ?rst bore
to said inlet-outlet passage, a passage in said valve body
passage means in said valve body separate from said
?rst and second passage means and connecting said ?rst
and second bores, check valve operating means in said
having one end communicating with said ?xed ori?ce and
communicating at its other end with said fourth bore
between the ends thereof, and a vent valve spool in said
valve body operable by said lowering valve spool to open 10 fourth bore controlling ?ow of ?uid from the passage
said check valve, means on said main control valve spool
communicating therewith between the ends thereof to
for controlling ?ow of ?uid from said ?rst bore through
said third outlet passage to thereby control venting and
said ?rst passage means to said inlet-outlet passage, check
pressurizing of said third bore adjacent the end of said
valve means in said ?rst passage means preventing reverse
?ow control valve spool remote from said inlet passage,
?uid ?ow therethrough, means on said main control valve 15 said vent valve spool being controlled by said means on
spool for controlling ?ow of ?uid through said third pas
said main control valve spool for controlling ?ow of
sage means connecting said ?rst aud second bores for
?uid from said ?rst bore to said inlet-outlet passage.
operating said lowering valve spool, means on said main
4. A control valve for a hydraulic actuator comprising,
control valve spool for metering the ?ow of ?uid from
a valve body having an inlet port adapted to be con
said inlet-outlet passage to said outlet passage, and means
nected to a pump, ?rst and second outlet ports adapted
providing a ?uid by-pass between said inlet passage and
to be connected to a ?uid reservoir, and an inlet-outlet
the reservoir when ?uid is not ?owing from said ?rst bore
port adapted to be connected to a hydraulic actuator,
to said inlet-outlet passage.
?rst passage means between said inlet-outlet port and said
3. A control valve for a hydraulic actuator comprising
?rst outlet port, a check valve in said ?rst passage means
a valve body, a ?rst bore in said valve body having an
normally preventing ?uid ?ow therethrough, ?rst con
end forming a ?rst outlet passage adapted to be con
trol valve means operable when actuated to open said
nected to a reservoir, a main control valve spool in said
check valve, second passage means between said inlet
?rst bore, an inlet passage in said valve body communi
port and said inlet-outlet port, a three position main
cating with said ?rst bore and adapted to be connected
control valve having a ?rst position wherein ?uid is di
to a pump, an inlet-outlet passage in said valve body 30 rected from said inlet port through said second passage
adapted to be connected to a hydraulic actuator, passage
means to said inlet-outlet port, a second position wherein
means in said valve body connecting said ?rst bore and
?uid is directed from said inlet port to said ?rst control
said inlet-outlet passage, passage means in said valve
valve means for actuation thereof whereby to open said
body connecting said inlet-outlet passage and said ?rst
check valve in said ?rst passage means between said inlet
outlet passage, a check valve in said passage means con 35 outlet port and said ?rst outlet port, and a third neutral
necting said inlet-outlet passage and said ?rst outlet pas
position, check valve means in said second passage means
sage normally preventing ?ow of ?uid from said inlet
preventing reverse ?uid ?ow therethrough from said inlet
outlet passage to said ?rst outlet passage, a second bore
outlet port, by-pass passage means between said inlet
in said valve body, a lowering valve spool in said second
port and said second outlet port, second control valve
bore, a passage in said valve body connecting said ?rst 40 means adapted to close said by-pass passage means when
and second bores, check valve operating means in said
said main control valve is in its ?rst position and to open
valve body operable by said lowering valve spool to open
said by-pass passage means when said main control valve
said check valve, means on said main control valve spool
is in either its second or third positions, and third control
for controlling ?ow of ?uid from said ?rst bore to said
valve means having a connection to said inlet port through
inlet-outlet passage, means on said main control valve 45 a fixed ori?ce, a connection to said second valve means,
spool for controlling ?ow of ?uid through said passage
and a connection to said inlet-outlet port only when said
connecting said ?rst and second bores for operating said
main control valve is in its ?rst position whereby said
lowering valve spool, means on said main control valve
third control valve means serves to control said second
spool for metering the ?ow of ?uid from said inlet-outlet
control valve means to close said by-pass passage means
passage to said ?rst outlet passage, a third bore in said 50 when said main control valve is in its ?rst position and
valve body communicating with said inlet passage, a
to open said by-pass passage means when said main con
second outlet passage in said valve body communicating
trol valve is in its second and third positions.
with said third bore and adapted to be connected to said
References Cited in the ?le of this patent
reservoir, a ?ow control valve spool in said third bore
for controlling ?ow of ?uid from said inlet passage to 55
UNITED STATES PATENTS
said second outlet passage, a passage in said valve body
2,575,507
Acton _______________ __ Nov. 20, 1951
connecting said passage means from said ?rst bore to
said inlet-outlet passage and said third bore and com
municating with said third bore adjacent the end of said
?ow control valve spool remote from said inlet passage, 80
a fourth bore in said valve body communicating at one
end with said passage means from said ?rst bore to said
inlet-outlet passage, a third outlet passage in said valve
body communicating with the other end of said fourth
2,654,349
2,691,964
2,847,030
2,868,174
Ziskal _________________ .._. Oct. 6,
‘Stickney ______________ __ Oct. 19,
McRae ______________ __ Aug, 12,
Shutt ________________ __ Jan. 13,
1953
1954
1958
1959
1,128,032
France __ ____________ __ Aug. 20, 1956
FOREIGN PATENTS
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