Note: Descriptions are shown in the official language in which they were submitted.
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Description
Pressure Reducing Valve With
Floating Stem for Make-up Vent
Technical Field
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This invention relates to pressure regulating
valve and in particular to pressure regulating valves
for use in fluid systems requiring ~enting of a system
component.
Background Art
In U. S. Letters Patent 3,840,049, of Jesse
L. Field, Jr., which patent is owned by the assignee
hereof, a control system for use in controlling posi-
tioning of a fluid motor is shown to includa a direc-
tional control valve which is operated by a pilo-t valve
so as to provide pressurized fluid selectively to
` opposite ends of a piston cylinder for suitably posi-
tioning the piston therein. The directional control
valve includes a make-up valve w]hich automatically
opens a bypass passage between the fluid motor ports
and a fluid return passage when necessary to prevent
cavitation of the motor, such as may result from an
overrunning condition from an external load force. The
pilot valve is connected with a float valve which has a
- ~ spool shifted by~the fluid pressure against a spring ~ 25 bias in the norma~operation of the system. When
desired, the manual pilot valve is shifted to a float
~` ~ position.
In U. S. Latters Patent 3,766,944, of Josaf
~ ~istler, a pilot-controlled fluid~flow regulating valve
is shown. The regulating valve includes a spool which
is moved relative to a neutral position by fluid from a
pilot valve. The regulating valve includes a manually
operated handle for controlling the disposition of a
piston mounted in the body of the pilot valve.
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Other background patents of interest in con-
nection with pressure regulating valves include those
of Fran~ Forster et al U. S. Letters Patent 3,69~,415;
Egon Zunzer U. S. Patent 3,817,153; Eugene E. Latimer
U. S. Patent 3,987,703, which patent is owned by the
assignee hereof; and British Patent 1,~94,400 of
Nordyhydraulic AB , a Swedish corpora-tion. The Zunzer
patent shows a pressure reducing pilot valve used in
another ~luid control applicatlon. The Forster et al
patent shows a pressure xe~ulating valve wherein the
control member bears upon the valve body via plurality
of springs, at least~one o~ which comes into play only
after the control member has been displaced through a
predetermined extent. The Forster et al patent shows a
regulating pilot valve similarly used in a dif~erent
system application.
In the Latimer patent, the pilot-controlled
hydraulic system has a load-supporting cylinder with a
valve assembly operative to automatically provide an
emergency source o pilot pressure upon failure of the
main pilot system. The control utilized pressurized
luid from the load-supporting motors for pilot opera-
tion of the system for emergency lowering of te load.
In the British patent, a regulating pilot
~alve provides an output under certain conditions so as
to throw another valve to either of two different
extreme positions.
~ hile the hackground art patents discussed
above show different forms of pressure regulating
valves such as used in load-lifting fluid systems, the
- structures thereof are relatively co~tly and complex
and do not provide the improved, simplified construction
of the present invention.
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Disclosure of Invention
The present invention is directed to
overcoming one or more of the problems as set forth
above.
In one aspect of the present invention, a
novel arrangement of a pressure regulating pilot valve
is provided. The arrangement results in improved
control for providing the venting function of said
valve O
In the present invention, the venting function
is produced by direct mechanical connection between the
connector from the handle to the spool of the pilot
valve.
The spool of the pilot valve is normally
spring-biased to provide the desired pressure
regulating function. The valve, however, is arranged
so that, under conditions wherein venting of the
control valve of the system i.~ desired, the biasing
spring is overcome to permit the desired direct
20 connection between the contro:L handle and valve spool, ~`
permitting the operator to positively move the valve
spool to an arrangement wherein the desired venting
connection is effected.
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As an example, in the illustrated embodiment,
the valve spool is provided with an annular groove
which is brought into alignment with an opening to tank
which is normally closed by a portion of the valve
~ ~ spool during the pressure regulating functioning
; ~ thereof. The connection between the annular recess and
-~ 30 the tank opening provides a communication to other
portions of the system so as to effect the desired
venting action.
In the illustrated embodiment, the venting of
the make-up valve of the system permits the load
supported by the fluid motor to float.
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~ore specifically, the invention comprehends a
: pressure regulating valve having wall means defining a
valve bore provided with an inlet passage, an exhaust
passage, and an outlet port, a movable valve spool in
said valve bore, and regulating means associated with
:~ said valve bore and said movable valve spool to provide
~ pressure regulation of fluid passing from said inlet
: passage through said valve bore to said outlet port,
said regulating means being further arranged to limit
movement of said valve spool to a first preselected
~ position in response to pressuri2ed fluid in said
;~ outlet port, the improvement comprising, means
.~ selectively directly mechanically connected with said
movable valve spool for moving the movable valve spool
~:: 15 beyond said first position to a second preselected
position, me~ns defining a second inlet passage, means
operable when said valve spool is disposed in said
second preselected position for providing a flow
passage from said second inle~ passage through said
pressure regulating valve to said exhaust passage, said
regulating means including a connector slidably
connected to said valve spool, and a spring positioned
, between the connector and said valve spool, and said
- mechanical means including an end portlon on said valve
`~ ~ 25 spool, a manual input element in engagement with said
connector and having a contact surface spaced from said
- end portion of the valve spool at the first position of
: the valve spool and in contact with said end portion at
; the second position.
The improved vaIve is advantageously adapted
for use in a fluid system having a reciprocable fluid
motor, and fluid supply means including a directional
control valve for controlling delivery of pressurized
fluid to the motor for reciprocally operating the same. ~-
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In the illustrated embodiment, the pressure
regulating valve includes first and second passage
means in the wall means thereof and recess means
associated with the movable valve spool communicating
between the first and second passage means when the
valve spool is in the second preselected position.
In the illustrated embodiment, the transfer
passage means is defined by an annular recess on the
movable valve spool.
Thus, the present invention provides a
pressure regulating valve simple and economical of
~` construction while yet providing the highly desirable advantages discussed aboveO
Brief Description of Drawin~
- Figure lA is a portion of a fluid system
having a pxessure regulating valve embodying the :
invention; and
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Figure lB is a continuation of the Figure lA
portion of the drawing and showing the connection of
1~ the directional control valve to the fluid motor in the
fluid system.
Bes't Mode for Carrying Out the Invention
In the exe3nplary embodiment of the invention
as disclosed in the drawing, a pressure regulating
valve generally designated 10 is provided for use with
a directional control valve 11 in controlling delivery
to a fluid motor 12 having a piston 13 reciprocable in
a cylinder 14. Pressurized fluid is delivered to the
opposite ends of cylinder 14 through a first supply
line 15 and a second supply line 16, as shown in Figure
lB. The fluid motor is exemplary only, it being obvious
that other forms of fluid motors, as well as a plurality
, thereof, may be used interchangeably with the disclosed
, motor.
¦ Pxessurized fluid for actuation o~ the fluid
motor is provided normally Erom a high pressure pump 17
having the output pressure thereof regulated by a
suitable relief valve 18 connected between the high
~, pressure outlet conduit 19 from pump 17 and the tank
reservoir 20 for controlling the fluid pressure in the
s~stem.
Directional control valve 11 is operated by
the pressure regulating valve which ef~ectively defines
a pilot valye. The pilot valve is controlled by a
manually operable handle 21. Thus, as seen in Figure
1~, the handle is swingable about a pivot 22 so as to
urge a first actuating arm 27 against a plunger 28 and
a second actuating arm 29 against a plunger 30 of the
pilot valve. The handle is swingable within a housing
23 carried on wall means 24 defining the valve body.
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Valve body 24 defines a first valve bore 25
receiving a first movable valve spool 26, and a second
valve bore 31 receiving a second movable valve spool,
32.
Spool 26 defines an axial, downwardly opening
bore 33 communicating with an outlet port 34 connected
to a transfer conduit 35. Spool 32 defines a similar
~; axial bore 36 opening to an outlet port 37 connected to
a transfer conduit 38.
Valve body 24 further defines a cross bore
defining an inlet passage 39 connected through a supply
~: conduit 40 to the pump 17.
:: As shown in Figure lA, spool 26 is provided
with a stem 41 which extends upwardly through a
connector 42 into a recess 43 at the lower end of
plunger 28. Similarly, spool 32 is provided with an
upwardly extending stem 44 extending through a
connector 45 into a recess 46 in the lower end of
plunger 30. A first coil spring 47 extends between
20 connector 42 and a shoulder 48 on spool 26 Eor biasing ~:
the spool resiliently downwardly relative to connector,
thereby spacing the upper end of the stem 41 from the
inner wall surface 49 of the recess 430 Similarly, a
~ coil spring 50 extends .between the connector 45 and a
:~ : 25 shoulder 51 on the spool 32 to bias the spool
~ downwardly and space the upper end of the stem 44 from
.~ an inner wall surface 5~ of the recess 46.
The connector 42 is biased upwardly by a coil
spring 53 extending between the connector and a
:: 30 shoulder 54 on the valve body. Similarly, a second
. spring 55 biases the connector 45 upwardly, spring 55
extending between connector 45 and a shoulder 56 on the
valve body. Thus, connector 42 is normally urged
: against a shoulder 57 of a plug 58 slidably carrying
` 35 the plunger 28, and connector 45 is urged against a
shoulder 59 on a plug 60 slidably carrying plunger 30.
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Spool 26 is provided with radial ports 61
opening to axial passage 33 and spool 32 is provided
with radial ports 62 opening to passage 36. As shown
ln Flgure lA, ports 61 and 62 normally spaced from the
inlet passage 39. However, when plunger 28 or plunger
30 is suitably depressed by manipulation of handle 21,
the corresponding connector 42 or 45 is moved downwardly
~ against the action of spring 53 or spring 55, respec-
: tively, so as to permi~ the spools 26 and 32 to be
resiliently moved downwardly by the action of the
hiasing springs 47 and 50, respectively. Thus, illustra-
tively, when the handle 21 is swung to the left, as
seen in Figure 1~, so as to depress plunger 28, spool
26 may be moved sufficiently downwardly to provide
:L5 communicat.ion between the inlet passage 39 and the
radial port 61, thereby conducting pressurized fluid
from the pump and supply conduit: 40 through the passage
33 of spool 26, outlet 34 and transfer conduit 35 to
the directional control valve l:L. The pressure of the
fluid in outlet port 34 acting on the end of spools 26
opposes the bias of springs 47 1:o position the spool 26
to a first preselected position in response to fluid
pressure in outlet port 34. An instantaneous pre-
: ~ selected pressure level in outlet port 34 as established
by the degree of input through handle 21 remains constantbecause any change of pressure in the outlet port 34
would resùlt in an unbalance of force opposing the
spring 47 resulting in movement of spool 26 to open or
~ close ports 61. This maintains the force balance
- 30 between spring 47 and the force created by fluid pressure
: in the outlet port 34 acting on the ends of spool 26.
This action pro~ides a pressure regulating function of
the valve 10. A similar ~ction occurs relati~e to port
~ 62 of spool 32 so as to provide pressure regulated
: 35 fluid through transfer conduit 38 as a function of the
pos~tioning of handle 21 in a clock~ise direction, as
seen:in Figure lA.
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As further shown in Figure lA, valve body 24
further defines an exhaust passage 63 connected through
an exhaust port 64 and a conduit 65 to the tank
reservoir 20. In the retracted position of the spools
26 and 32, the ports 61 and 62 thereof are in
communication with the exhaust pssage so that normally
- conduit 35 and 38 are vented when the handle 21 is in
the neutral, centered position of Figure lA.
Referring now more specifically to Figure lB,
the directional control valve 11 defines a spool valve
. having a body 66 defining a valve bore 67 in which is
reciprocally mounted a spool 68. Conduit 35 opens
through a closure 69 to one end of the bore 67, and
conduit 38 opens through a closure 70 through the
opposite end of the bore.
Spool 68 is centered in the valve bore 67 by a
first biasing spring 71 extenAing between closure 69
and one end of the spool and a second biasing spring 72
extending between closure 70 and the opposite end of
the spool. High pressure supply conduit 19 is
connected through the valve body 66 to an annular
recess 73 at the midportion of bore 67. A second
annular recess 74 is spaced axially toward closure 69
from annular recess 73 and a second annular recess 75
is spaced axially in the opposite direction from ~he
~ recess 73. Recess 74 is connected through a passage 76
; to the fluid supply line 15 and recess 75 is connected
~` through a passage 77 to the fluid supply line 16.
: Outboard of annular recess 74, the valve body
is provided with an exhaust annular recess 78 and
outboard of the recess 75, the valve body is provided
. with a second annular exhaust recess 79. The exhaust
recesses are connected through an exhaust passage 80
: and exhaust conduit 81 to the reservoir tank 20.
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Spool 68 is provided with a first annular,
radially outwardly opening recess B2 which is in
communication with body recess 74 and spaced from body
recess 73 in the centered arrangement of the control
valve 11, as shown in Figure lB. The spool is provided
with a second annular, radially outwardly opening
recess 83 in communication with recess 75 and out of
communication with recess 73 when the spool is in the
centered position of Figure lB.
Directional control valve 11 further defines a
pair of make-up valves 84 and 85, respectively.
Make-up valve B5 is defined by a movable valve member
86 received in a valve bore 87 in valve body 66 and is
normally biased by a spring 88 into seated relationship
with a valve seat 89 opening to the recess 78. The
valve member 86 defines an axial passage 90 in
~ communication with a port 91 in the valve body
`` connected to a conduit 92. The valve member further
defines a port 93 opening to a valve chamber 94
communicating with the passage 76.
-~ Make-up valve 85 is generally similar to
make up valve 84 except for the omission of the port 91
and conduit connection 92. Thus, make-up valve 85
includes a valve member 95 biased by a spring 96
against a valve seat 97.
: In the normal operation of the fluid system,
~: delivery of the pressurized fluid to motor 12 is effect-
ed by suitable movement of the spool 68 of directional
` control valve 11 by selectively providing pressurized
fluid through the pilot valve 10 and either of control
conduits 35 or 38. Thus, if it is desired to more the
fluid piston 89 opening 13 of fluid motor 12 to the
; right~ as seen in Figure lB, the suitable manipulation
of handle 21 of the pilot valve as shown in Figure lA,
is effected to provide pressurized fluid through the
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spool passage 33 to the transfer conduit 35, thereby
applying pressure to the lefthand end of spool 68 of
~alve 11 and moving recess 82 to the right so as to
provide communication between recess 73 and recess 74,
thereby providing pressurized fluid from conduit 19
through the control valve to the supply line 15. At
the same time, recess 83 is moved into communication
with recess 79 so as to provide an exhaust connection
from line 16 through the directional control ~alve to
the exhaust conduit 81 and tank reser~oir 20.
Conversely, when it is desired to move the
piston 13 to the left, as seen in Figure lB, pilot
control handle 21 is moved in a clockwise direction so
as to provide communication between supply passage 39
and spool passage 36 through port 62, thereby providing
~` pressurized fluid through the transfer conduit 38 to
the righ~hand end of the directional control valve,
thereby moving spool 68 to the left and positioning
reaess 83 so as to have communication between recess 73
and recess 75 of the valve body, thereby providing
~ pressurized fluid from conduit I9 through passage 77 to
.. trans~er conduit 16. At the same time, spool recess 82
- is moved into communication wi*h recess 78 and recess
74 of the ~alve body to provide an exhaust passage from
conduit 15 to the exhaust conduit 81.
. Thus, valve 10 functions as a pressure regu-
lating pilot valve for selectively moving the spool 68
of the directional control valve 11 as a function of
the movement of handle 21 of the pilot valve. Make-up
valves 84 and 85 are provided for effectively preventing
. cavitation of the fluid motor 12 such as when the load
forces thereon tend to cause the piston 13 to move moxe
rapidly than the flow o~ :Eluid from the pump 17 can
provide through the lines 15,16. If for example, the
cylinder 14 is retracting rapidly as noted above during
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a lowering condition, the pressure in line 15 and
passage 76 would drop. This drop in pressure is also
felt in valve chamber 87 via valve chamber 94 and port
93. When the pressure in passage 76 drops below the
tank pressure in exhaust passage 80 and annulus 78, the
difference of pressure will act on the end of valve
member 86 lifting i~ from its seat 89 thus providing
make-up fluid to the cylinder 14 through passage 76 end
]ine 15. Resultingly, fluid from conduit 16 is
transferred through the drain passage 80 into recess 78
and, thus, into the passage 76 as a result of the
unseating of valve member 86 from seat 89 to augment
the fluid flow to the conduit 15 and, thus, effectively
prevent cavitation of the motor 12
As indicated briefly above, the improved
pressure regulating pilot valve 10 is arranged to
provide an improved means for permitting the system to
operate in a float condition wherein the piston 13 may
float in the cylinder 14. To effect such a ~loat
control, the pilot valve 10 is arranged to vent the
make-up valve 84 and maintain spool 68 in its shifted
position so that pressuri2ed ~luid can move past the
` make-up valve and allow intercommunication between the
pump, tank and cylinder lines.
To this end, spool 2~ is provided with an
annular, radially outwardly opening recess 98 which is
in communication with a flow passage 99 in the valve
body 24 to which conduit 92 is connected. The valve
body defines a radially inwardly opening annular recess
30 100 spaced from passage 99. During normal pressure
regulating reciprocation o~ spool 26, recess 98 is
maintained in spaced relationship to recess 100.
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As shown in Figure lA, recess 100 is con-
nected through a passage 101 to the exhaust passage 63.
:~ When it is desired to ~ent the make-up valve 84, spool
~ 26 is moved to a position wherein recess 98 communicates
: 5 with recess 100 so as to connect conduit 92 to exhaust
passage 63 and, thus, through conduit 65 to reservoir
: tank 20, thereby venting the bac~side of valve member
86 and permittin~ the make-up valve 84 to open so that
~ the fluid may pass into conduit 15.
10 Movement of recess 98 into communication with
recess 100 is effected by a direct mechanical connection
between handle arm 27 and spool 26. The direct mechani-
cal connection is effected by movement of plunger 28
: dcwnwardly to bring the plunger surface 49 into engage-
ment with the upper end portion 102 of spool 26.
~ , Resultingly, downward movement of arm 27 and concurrent
downward movement of'plunger 28 causes a direct downward
, movement of spool 26 so as to move recess ~8 into
'. communication with recess 100 against the upward biasing
l 20 action of spring 53.
;'~ Thus, the provision of recess 98 in spool 26
and.the connection between the backside of make-up
I valve 84 through conduit 92 to this recess for selec-
.' tively exhausting the valve through the exhaust recess
: 25 100, passage 101, and passage 63 of the pilot valve 10 ::
effec~s a simple, low cost float control of the fluid
motor eliminating costly and complicated additional
'~` valving and fluid circuitry of the conventional systems.
: Industr'i'al'Applicability
: 30 The control system of the present invention
~ is ad~antageously adapted for a wide range o~ industrial
: applications. Illust~atively, the fluid motor 12 may
be utilized in connection with a wide range of appa- .
- ratuses requiring a float posltion. ~n one example, a
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loader may be utilized to push the bucket thereof along
the surface of the ground. On uneven surfaces, it is
desirable to permit the bucket to follow the contour of
the ground. Provision of a float operation in the
control system permits the bucket to more effectively
follow the contour.
The present invention utilizes one of -the
make-up valves of the directional control valve, which
is normally proyided to control caVitation of ~he
motor, as a means for providing the desirable float
conditionO
Other aspects, objects and advantages of this
inyention can be obtained from a study of the drawings,
the disclosure and the appended claims. The foregoing
disclosure of specific embodiments ;s illustrative of
the broad invention concepts comprehended by the inven-
tion.
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