CA1063871A - Fluid operated hydraulic pump including an improved hydraulic fluid pressure release assembly - Google Patents
Fluid operated hydraulic pump including an improved hydraulic fluid pressure release assemblyInfo
- Publication number
- CA1063871A CA1063871A CA283,992A CA283992A CA1063871A CA 1063871 A CA1063871 A CA 1063871A CA 283992 A CA283992 A CA 283992A CA 1063871 A CA1063871 A CA 1063871A
- Authority
- CA
- Canada
- Prior art keywords
- fluid
- hydraulic
- passage
- plunger
- valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
- F04B9/08—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid
- F04B9/12—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air
- F04B9/123—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air having only one pumping chamber
- F04B9/127—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being fluid the fluid being elastic, e.g. steam or air having only one pumping chamber rectilinear movement of the pumping member in the working direction being obtained by a single-acting elastic-fluid motor, e.g. actuated in the other direction by gravity or a spring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
- F01B11/00—Reciprocating-piston machines or engines without rotary main shaft, e.g. of free-piston type
- F01B11/007—Reciprocating-piston machines or engines without rotary main shaft, e.g. of free-piston type in which the movement in only one direction is obtained by a single acting piston motor, e.g. with actuation in the other direction by spring means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L25/00—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means
- F01L25/02—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means
- F01L25/04—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means by working-fluid of machine or engine, e.g. free-piston machine
- F01L25/06—Arrangements with main and auxiliary valves, at least one of them being fluid-driven
- F01L25/066—Arrangements with main and auxiliary valves, at least one of them being fluid-driven piston or piston-rod being used as auxiliary valve
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
- F04B49/24—Bypassing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/10—Valves; Arrangement of valves
- F04B53/1002—Ball valves
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Details Of Reciprocating Pumps (AREA)
- Check Valves (AREA)
- Reciprocating Pumps (AREA)
Abstract
FLUID OPERATED HYDRAULIC PUMP INCLUDING AN
IMPROVED HYDRAULIC FLUID PRESSURE RELEASE ASSEMBLY
ABSTRACT
A fluid operated hydraulic pump of the type using air pressure to produce high pressure hydraulic fluid whereby hydraulic fluid can be conveyed to a hydraulic tool or the like, and wherein the hydraulic pump includes an easily actuated release valve to facilitate return of high pressure hydraulic fluid from the hydraulic tool to the fluid reservoir of the hydraulic pump and including a treadle having a curvilinear cam surface for engaging the release valve to actuate it. The hydraulic pump also includes a continuously open hydraulic fluid pressure passage connected to the high pressure output passage of the hydraulic pump and in communication with the release valve bore to facilitate fluid pressure on a shoulder of the release valve thereby maintaining a balance of fluid pressure force on the release valve and facilitating axial movement of the valve with application of only a small axial force.
IMPROVED HYDRAULIC FLUID PRESSURE RELEASE ASSEMBLY
ABSTRACT
A fluid operated hydraulic pump of the type using air pressure to produce high pressure hydraulic fluid whereby hydraulic fluid can be conveyed to a hydraulic tool or the like, and wherein the hydraulic pump includes an easily actuated release valve to facilitate return of high pressure hydraulic fluid from the hydraulic tool to the fluid reservoir of the hydraulic pump and including a treadle having a curvilinear cam surface for engaging the release valve to actuate it. The hydraulic pump also includes a continuously open hydraulic fluid pressure passage connected to the high pressure output passage of the hydraulic pump and in communication with the release valve bore to facilitate fluid pressure on a shoulder of the release valve thereby maintaining a balance of fluid pressure force on the release valve and facilitating axial movement of the valve with application of only a small axial force.
Description
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B~CKGl~OUND OF T~IE INVENTION
The present invention relates generally to improvements in hydraulic pressure applying devices and more particularly to improve-ments in appar~tus for delivering hydraulic fluid under pressure to such devices.
Fluid actuated hydraulic fluid pressure producing units are shown, for e~ample, in U. S. Patent No. 3, 041, 975 issued July 3, 1962 to Atherton et al. and in U. S. Patent No. 3, 463, 053 issued August 26, 1969 to Leibundgut, both of these patents being assigned to an assignee ` in common with that of the present invention. Another type of similar devlce is shown in U.S. Patent No. 3, 788, 781, issued January 29, 1974 to McClocklin.
Fluid actuated hydraulic power units of the type referred bo in the above patents are intended to use a source of air pressure, such as those commonly used in garages, salvage operation9, or in industrial applications, and which produce air pressure on the order of 100 psi, to supply high pressure hydraulic fluid at pressures o~ the order of 10, 000 psi to operate .. - . . ..
hydraulic fluid motors or other hydraulic tools. Sucli power units include - a reciprocating piston air motor~ the piston !being driven by air pressure . .
and functional to reciprocate the piston of a hydraulic pump to thereby 20 drive the hydraulic pump and supply high pressure hydraulic fluid through an output passage to a hydraulic tool~
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In order to facilitate return of the hydraulic fluid from the hydraulic tool to the hydraulic fluid reservoir, a release fluid passage~,vay is provided and fluid flow through the passageway is controlled by a release valve. Due ` tP the high hydraulic pressure which can be developed by the power units, . ,
B~CKGl~OUND OF T~IE INVENTION
The present invention relates generally to improvements in hydraulic pressure applying devices and more particularly to improve-ments in appar~tus for delivering hydraulic fluid under pressure to such devices.
Fluid actuated hydraulic fluid pressure producing units are shown, for e~ample, in U. S. Patent No. 3, 041, 975 issued July 3, 1962 to Atherton et al. and in U. S. Patent No. 3, 463, 053 issued August 26, 1969 to Leibundgut, both of these patents being assigned to an assignee ` in common with that of the present invention. Another type of similar devlce is shown in U.S. Patent No. 3, 788, 781, issued January 29, 1974 to McClocklin.
Fluid actuated hydraulic power units of the type referred bo in the above patents are intended to use a source of air pressure, such as those commonly used in garages, salvage operation9, or in industrial applications, and which produce air pressure on the order of 100 psi, to supply high pressure hydraulic fluid at pressures o~ the order of 10, 000 psi to operate .. - . . ..
hydraulic fluid motors or other hydraulic tools. Sucli power units include - a reciprocating piston air motor~ the piston !being driven by air pressure . .
and functional to reciprocate the piston of a hydraulic pump to thereby 20 drive the hydraulic pump and supply high pressure hydraulic fluid through an output passage to a hydraulic tool~
.. ..
In order to facilitate return of the hydraulic fluid from the hydraulic tool to the hydraulic fluid reservoir, a release fluid passage~,vay is provided and fluid flow through the passageway is controlled by a release valve. Due ` tP the high hydraulic pressure which can be developed by the power units, . ,
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the forces acting on the release valve are substantial. However, it is desireable that the release valve be easily manually operable.
The McClocklin patent cited above suggests a release valve having concentric axially reciprocating plungers, the central plunger comprising a thin member for unseating a small check ball in order to provide a first - means for initially relieving hydraulic~pressure and the outer reciprocable plunger functional to permit subsequent increased hydraulic fluid flow.
The device of McClocklin is subject to the disadvantages that the central plunger and check ball are of such a small cross sectional diameters that 10 they do not withstand continued use and the sequential mode of operation of this type of release valve does not facilit~te a smooth valve opèration or return flow of hydraulic fluid to the reservoir.
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the forces acting on the release valve are substantial. However, it is desireable that the release valve be easily manually operable.
The McClocklin patent cited above suggests a release valve having concentric axially reciprocating plungers, the central plunger comprising a thin member for unseating a small check ball in order to provide a first - means for initially relieving hydraulic~pressure and the outer reciprocable plunger functional to permit subsequent increased hydraulic fluid flow.
The device of McClocklin is subject to the disadvantages that the central plunger and check ball are of such a small cross sectional diameters that 10 they do not withstand continued use and the sequential mode of operation of this type of release valve does not facilit~te a smooth valve opèration or return flow of hydraulic fluid to the reservoir.
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SUM~RY OF THE INVENTION
The present invention provides an improved fluid operated hydraulic power unit having an improved hydraulic fluid release means for permitting return flow of hydraulic fluid from a hydraulic tool back to the reservoir of the power unit and having the advantages of being easily manually operable and providing a smooth fluid flow.
The invention comprises in a fluid actuated hydraulic pump: a body and including a motor chamber formed in one end of said body, and a hydraulic reservoir formed in the other end of said body and axially aligned with said motor chamber, means for pumping hydraulic fluid under pressure from said reservoir, said means for pumping including a hydraulic valve block disposed in axial alignment between said motor chamber and said reservoir, said valve block having an output passage for directing fluid under pressure from said pump to a point of use, a release passage from said . output passage to a point of pressure relief, and means for controlling fluid . flow from said output passage through said release passage, said means for .i controlling including a release valve assembly having opposite ends and .. I .
positioned in a valve bore in said hydraulic valve block, said release valve assembly having a reciprocable plunger, a valve seat between said output : :~
;: 20 passage and said release passage, a check ball engageable with said plunger, :~
. a biasing spring for urging said check ball against said valve seat, said ~ .
check ball being movable by said plunger from a first seated position wherein . fluid communication between said output passage and said release passage is prevented to a second unseated position for causing fluid communication .
:~ between said output passage and said release passage, means for selectively .
moving said plunger, and means for applying fluid pressure force on said reciprocable plunger for biasing said check ball toward said second unseated : : :
position, said means for applying fluid pressure force on said reciprocable plunger including a continually open hydraulic fluid passage from said out- :
put passage to said release passage, said open hydraulic fluid passage .; located radially outwardly of said valve bore. ~:
In the disclosed embodiment, the hydraulic pump includes a ~ .
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reciprocable hydraulic fluid pumping piston in turn driven by a piston of a fluid motor positioned adjacent to and in axial alignment with the hydraulic pump. The hydraulic fluid reservoir is also positioned abutting the hydraulic pump opposite the fluid motor. The hydraulic pump includes an output passage connectable to a hydraulic tool whereby hydraulic pressure developed by the hydraulic fluid pumping piston can be delivered to the tool, and also includes a release passage between the output passage and the reservoir to permit return of hydraulic fluid from the hydraulic tool. A
check valve, including a spring biased check ball, is disposed between the output passage and the release passage to releasably restrict the fluid flow i therethrough. In order to provide means for moving the check ball off of the check valve seat to permit fluid flow from the output passage to the release passage, a release valve plunger is disposed in a valve bore and has an end engageable against the check ball. The opposite end of the release valve plunger ends outwardly from the hydraulic pump and is engaged by a curved camming surface of a pivotable treadle. The release valve plunger is also provided with a roller at its outwardly extending end for engagement against the camming surface.
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The treadle is pivotably moveable such that the camming surface will engage the roller of the release valve plunger and cause axial movement of the release valve plunger whereby the opposite end of the release valve plunger can engage the check ball to move it away from its valve seat thereby permitting fluid flow from the output passage to the release passage.
In order to facilitate movement of the release valve plunger and the check ball with the application of only a relatively small axial force on the release valve plunger, means are provided for applying an axial fluid pres-sure force on the release valve plunger biasing the release valve plunger 10 toward the check ball to thereby substantially balance the force on the check ball forcing it against its valve seat. ~ continually open fluid passage disposed radially outwardly from the release valve provides fluid communi-cation from the output passage to an annular chamber surrounding the release valve bore and intermediate its ends whereby fluid pressure in the output passage is conve~red to the annular chamber. The release valve plunger is provided with a shoulder adjacent the annular chamber whereby :fluid pressure in the annular chamber generates an axial force on the release valve plunger toward the check ball, The effective cross-sectional area of the shoulder is slightly less than the effective cross-sectional area 20 of the bore of the valve seat whereby the forces on the release valve plunger and on the check ball, caused by fluid pressure in the output passage, are nearly equal and only a relatively small axial force on the release valve plunger is needed to move the check ball away from the valve seat.
The axial force on the release valve plunger necessary to unseat the check ball and open the check valve is applied by downward force of the treadle camming surface on the plunger roller, The camming surface i`
is particularly constructed to have a very slight wedge angLe at that part ~
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of the camming surface first contacting the release valve plunger roller whereby initial relative movement of the camming surface causes only a slight axial movement of the plunger. The wedge angle of the camming surface increases relative to its length, however, whereby further relative movement of the camming surface and roller results in greater axial movement of the plunger. Thus the relative shape of the camming surface facilitates substantial movement of the release valve plunger and check ball and increased fluid flow through the release passage once fluid flow through the release passage has been initiated and facilitates a smooth 10 increase in the rate of fluid flow from the hydraulic tool to the reservoir.
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BiRIEF DESCRIPTION OF THE DRAWINGS
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:; FIGURE 1 is a side elevation view of a fluid actuated hydraulic power unit of the present invention; . :
FIGURE 2 is an end elevation view of the power unit shown in FIG. 1;
FIGURE 3 is a cross-sectional plan view of the power unit shown ~: :
in FIG. 1 and is taken generally along line 3-3 in FIG. 1;
-: FIGURE 4 is a partial cross-sectional plan view similar to ~IG. 3 ::~
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:~ but distorted to show the air motor throttle valve generally in a side eleva- ~ ~ ~
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; ~ tion cross-section and showing the air piston of the air motor in- its fully ~ ~ ;
extended position;
FIGURE 5is a view similar to FIG. 4 but showing the air piston in a retracted poaition FIGURE 6 i9 an enlarged partial view of the power unit shown in FIG. 1 with portions cut away in the intere~st of clarity FIGURE 7 is a view similar to FIG. 6 but showing the hydraulic .` : fluid release plunger in a fluid release position; and - -. .
FIGURE 8 is an enlarged view of the hydraulic fluid release plunger shown in FIG, 7.
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Referring to the drawings, the power unit shown therein as embody-ing the invention comprises, in general, a unitary body 10 supported by a base 12 and having an actuating lever or treadle 14 pivoted thereon. The body 10 includes a fluid or air motor portion 16 closed at one end- by an air motor valve block 18 and having a hydraulic reservoir housing 20 e~tending from its opposite end and a hydraulic pump valve block 22 interposed between .
the air motor 16 and the hydraulic reservoir housing 20. The body 10 is of generally cylindrical shape, and the air motor portion 16, air motor valve 1~ block 18, hydraulic reservoir housing 20, and hydraulic pump valve block 22 are in axial alignment, The air motor 16 and the air motor valve block 18 are shown as being comprised from plastic and can be advantageously formed by inJection molding, however, a plurality of other materials such as die ....
cast aluminum could be used. The air motor 16 is secured to the ~ .
hyd.raulic pump valve block 22 by a restrainlng band 24 which can be received around an end portion 17 of air motor 16 whereby that end OI the plastic ~ . air motor can be clamped against a projecting annular end 26 of the hydraulic valve block 22 by means of a tightening screw 28. The hydraulic reservoir housing 20 is comprised in part of a cylindrical sleeve 21 whic~l includes an 20 open end which is received around an end 27 of the hydraulic valve block 22 and secured thereto by screws 30.
. Live air or other pressurized fluid :Erom a suitable source 32 (FIG. 3) is admitted through a conduit 33 to the air motor valve block 18 by means of an air inlet coupling 34, which is threadably received within a bore 35 in the valve block 1~, and high pressure hydraulic fluid is discharged from the hydraulic pump valve block 22 through a high pressure pump outlet swivel . . .
coupling 36, Air Motor . ~ ;
Referring to the air motor 16 and air motor valve block 18 shown in . -FIGS. 3-6, air from the supply source 32 is intended to pass through the àir inlet coupling 34 and through an air filter 38 threadably journalled ~: :
therein and within the bore 35. The flow of air through the air inlet coupling 3g is governed by a check valve poppet 40 which includes a flange 4 2 at one end receivable against a valve seat 44 (FIG. 4) to prevent fluid flow into the air motor. The check vall7e poppet 40 is a~:ially slideably supported in an ~ :
axial bore 46 in the air motor valve block 18 and is co-axial with the longi~
10 tudinal axis of the air motor 16, hydraulic reservoir housing 20, and hydraulic valve block 22, and the axial position of the check valve poppet 40 .
is governed by a spring biased shuttle valve 48 as will be described herein- .
. - ~ a~ter. When the check valve poppet 40 is in a position to permit air flow .
into the bore 96 (FIG. 3), the air will then flow th~ ugh a supply passage 50 ~FIG, 5) in the air valve block 18 to a cylindrical bore 52 housing an actuating ..
throttle valve assembly 54. The actuati.ng throttle valve assembly 54 is . slideably received in the bore 52 and fluid-tight relationship is maintained by resilient O-ring seals 56. The actuating throttle valve asse~bly 54 includes a generally cylindrical valve body 55 and a slideable tnrottle valve poppet 57 20 which is axially movable within a bore 58 in the valve body 55 and which in-cludes a flange 60 at one end normally seated against a valve seat 62 of the '. valve body 55 and biased toward a fluid flow restricting position by air pres- -.
sure in the supply passage 50O The valve body 55 also includes a port 6 ' ~ .
therethrough in open communication with the axial bore 58 in the valve body 55 .; and intended to facilitate air flow through an axial supply passage 66 in the air valve block 18 and air motor 16 whereby air can be supplied to the air . .
motor displacement chamber 68.
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The air motor portion 16 also includes an axialLy aligned stepped bore or cylinder 70 adjacent its end wall 71, the bore 70 being defined by a generall~- tubular axially projecting sleeve 72 which is receivable in fluid-tight relationship within the air motor valve block 18. The stepped bore 70 slideably houses the shuttLe valve poppet 4B which is in turn functional to ! permit exhaust from the chamber 68 through an exhaust port 85 and into an annular expansion chamber 87 in the air motor valve block 18 and finally through exhaust ports 74 in the air motor valve block 18. The shuttle valve poppet 48 is positioned in axial alignment wiith and can be secured to the -~
check valve poppet 40 by a screw 83 received through shuttle valve poppet 48 ~ ..
and threadably received in a bore 40b in the check valve poppet 40 such that the shuttle valve poppet 48 is also functional to control axial movement of the check valve poppet 40. The shuttle valve poppet 48 also includes a molded resilient piston portion 75 at one end and axially slideable within the bore 70. A coil spring 76 is positioned between an annular inwardly . ~ . proJecting flange 78 of the air motor 16 a~d the piston portion 75 of the - shuttle valve poppet 48. A circular disc-like resilient seal 82 is secured by means of a backup washer 82a and a screw 83 to the end of the shuttle valve poppet 48 opposite the piston 75 and is normally received against a . 20 seat 84 of the annular flange 78 to prevent exhaust of air from the chamber ~ 68 through the bore 70.
.;. The air motor 16 also includes a cylinder 86 which defines the air motor displacement chamber 68 &nd which receives an axially movable piston 90 therein. A fluid-tight seal is maintained between the cylinder walls of the cylinder 86 and the periphery of the piston 90 by a resilient seal 108.
In order to permit reciprocation of the piston 90 in the displacement cham-ber 68, fluid communication between the ambient atmosphere and that portion .
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includes an annular groove 110 surrounding its circumference and a plurality - ~ of ports 112 to provide communication between the displacement chamber 68 and the groove 110 and to permit air flow through the port 92a as the piston 90 reaches the end of its forward stroke.
The displacement chamber 68 is also vented through a port 92 which is remote from the air motor valve block 18 and in communication with the bore 70 through a passage 94, and through a passage 96 in the air motor ~valve block 18. The port 92 is positioned such that it is adapted to be un-covered by the air motor piston 90 only when the piston 90 reaches the end 10 of its forward stroke.
Seated against the front face of thè air motor piston 90 IS a small diameter hydraulic fluid pump piston 98 slideably receivable in a cylinder 99 and operable to pump hydraulic fluid through passages in the hydraulic block 22 as will hereinafter more fully appear. The rear of the hydraulic pump piston 98 extends into the air motor displacement chamber 68 and is formed with an enlarged head 100 having a rounded or spherical bearing surface 101 urged against a complementary rounded surface 102 in the face .~
of the piston 90 hy a spring 104 compressed between and seated against the rear of the hydraulic valve block 22 and an annular disc 106 supported by 20 the pump piston 98 and adjacent to its head end l00.
Air Motor Operation In operation and assuming that the piston 90 begins its reciprocal -.~: . : :
:~ movement in the position shown in FIG. 3, wherein the force of the spring 104 urges the piston 90 against the shuttle valve poppet 48 thereby causing .
the check valve poppet 40 to move axially in bore 46 and the flange 42 thereof . ~
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to be movecl atvay from the valve seat 44 whereby air can pass through the bore 46 into the passageway 50 (FIG. 4). To cause actuation of the air motor, the operator depresses treadle 14 such that the tab 120 (FIG. 6) at the end of the treadle 14 engages the upwardly projecting end 59 of the actuating throttle valve poppet 57 thereby moving the flange 60 away from the valve seat 62 and permitting compressed air to flow from supply passagc ~0 through passages 64 and 66 into the cylinder cavity 68. The resulting air pressure in cavity 68 will force air piston 90 and the hydraulic fluid piston 98to the position shown in FIG. 4 thereby providing a hydraulic fluid pumping : 10 effect. Such movement of the piston 90 to the end of its stroke will uncover :: the port 92 thereby permitting compressed air in the displacement chamber 68 to communicate through passages 94 and 96 with the cylinder 70. The com-pressed air flowing through passages 94 and 96 into the cylinder 70 will cause the piston portion 75 of the shuttle valve poppet 48 and the check valve poppet 40 attached thereto to move to the left to the position shown in FIG. 4 agaiQst the force of the spring 76, Movement of the piston portion 75 to the position shown in FIG. 4 causes the flange 42 of the check valve poppet 40 to be received aga~inst the seat 44 thereby restricting further flow of air through the passage 50 into the air motor 16.
When the piston portion 75 of the shuttle valve 48 moves to the position shown in FIG. 4, the dise 82 also moves away from the seal 84 thereby permitting the compressed air within the displacement chamber 68 to exhaust through the bore 7d, through the exhaust port 85, into the annular expansion chamber 87 containing a number of baffles 89, and finally through the plurality of small exhaust passages 74.
.~s the compressed air is thus exhausted from the displacement chamber 68, the spring 104 forces the piston 90 to return toward its original position as shown in FIG. 3. As shown in FIG. 5, as the piston 9o nears its original position, the piston 90 contacts the screw 83 and backup washer 82a thereby causing the shuttle valve poppet 48 and the check valve poppet 40 to be forced to the right and continued movement of the piston 90 cause3 the resilient disc 82 to be received in sealing engagement against the seal 84 to prevent further exhaust flow from chamber 68 and simultaneously ~-forces the flange 42 of the check valve poppet 40 away from the seat 44 10 . to permit air flow from the supply source 32 into the passage 50. Further- ~ .
~ more, it will thus be appreciated that before the piston 90 reach0s the end ,l ~ of its return stroke, the flange 42 of the chec~ valve poppet 40 is forced away from the seat 44 sufficiently that air flow through the passage 50 and into the displacement chamber 68 will effect damping of the return stroke of the piston 90. As long as the treadle 14 is depressed and the actuating throttle valve 57 is open, whereby passage 50 and the passages 64 and 66 are in communication, the air motor will continue to pump in a similar .~ . fashion as that described above until hydraulic fluid pressure in the cylinder .,. ,. . : :
99 reaches a desired level.
: 20 Hydraulic Fluid Pump -~
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. In this manner, the hydraulic pump piston 98 is thus caused to recip-rocate within the hydrau~ic pump cylinder 99 by the combined action of the .
air motor piston 90 and the return spring 104. While the hydraulic pump cylinder 99 may be formed directly in the hydraulic pump valve block 22, it is preferably formed as shown in a readily removable and replaceable : .
cartridge 124 which is threadably received within a bore 125 in the hydraulic ` .
. valve block 22. Fluid-tight relationship between the hydraulic piston 98 ~ :
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: :-and cylinder 99 is maintained by a seal 126 secured within the cartridge 124 by a backup ring 128 and a snap ring 130. The hydraulic circuitry of the hydraulic pump is encased within the hydraulic valve block 22 (FIG. 3) and comprises in part a suction or supply passage 131 extending from the hydraulic r eservoir 132 within the hydraulic reservoir housing 2~ past a spring biased ball check valve 134 to the hydraulic pressure chamber 135.
The ball check valve 134 includes a ball 136 being seated against a removable seat 138 to close the passage 131 during the forward stroke of the piston 98 and being unseated to open the passage 131 during the return or suction stroke : . 10 of the piston 98. The ball 136 is biased against the seat 138 by a spring 139 supported by the end of the replaceable cartridge 124. The passage 131 ex-tends through a generally hollow cylindrical hydraulic fluid filter 137 which is threadably secured within a bore 137a in the hydraulic valve bloc~ 22 and which extends into the reservoir 132, The fluid filter 137 is constructed from a material which permits hydraulic fluid to flow through it but which prevents impurities from entering the pumping chamber 135.
The hydraulic valve block 22 also includes a high pressure discharge Gr outlet passageway 141 past a one-way ball check valve 142. The ball check valve 142 is comprised of a valve seat 143 threadably and removably secured within a bore 144 in the hydraulic valve block 22 and a check ball 146 biased against the valve seat 143 by a spring 147. The outlet passage 141 is defined : by an axially extending bore 140 through the valve seat 193 and by a longitu-dinal bore through a cylindrical sleeve 183 which has one end threadably secured within the bore 144 of the valve block 22 and another end supporting a freely rotatable coupling member 148 of the swivel coupling 36. The coupling member 148 includes a stepped central bore 149 therein in communication with the passage 141, the central bore 149 including a .
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fluid-tight seal is maintained between the coupling member 148 and the cylindrical sleeve 183 by a resilient O-ring 150 and relative rotation of the -coupling 148 around the end of the sleeve 183 is facilitated by a pair of retaining pins 152 extending through the coupling member 148 and receivable in a circumferential groove 152a in the sleeve 183.
Also formed in the valve block 22 is a relief valve assembly 150 comprising a generally cylindrical valve housing 151 threadably secured within a bore 152 in the valve block 22, the relief valve assembly 150 intended to provide communication of hydraulic fluid between the hydraulic pressure chamber 135 and the reservoir 132 in the event the fLuid pressure in the pressure chamber 135 becomes too great. A port 154 in the valve block 22 extends from the hydraulic pressure chamber 135 into the bore 152 and a similar but transverse bore 156 extends from the bore 152 into the hydraulic reservoir 132. The cylindrical valve housing includes a central chamber 153 in communication with the port 154 through a bore 155 and simi-larly in communication with transverse bore 156 through a bore 159, howeverg fluid flow therethrough is prevented by means of a spring biasèd check vaLve - 157 in the valve housing 151, the check valve 157 being comprised of a ball 158 received against a seat 160 and biased thereagainst by a spring 162 and a ball support member 164. The biasing force of the spring 162 can be -adjusted by an accessible screw 166.
The oil in the reservoir 132 is confined within a container formed by a flexible membrane or bladder 168 having a generally cylindrical shape and having one end reversed inwardly and received in fluid-tight relationship in a circumferential groove 167 around a cylindrical plug housing 169 thread- `
ably received in a bore 171 in the end of the hydraulic reservoir housing 20.
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The other encl of the container 168 is secured between the wall of the hydraulic reservoir housing 20 and the circumferential periphery of the valve block 22 and includes a circumferential bead 170 received within a circumferential groove 172 around the hydraulic valve block 22. The chamber 173 of the `:~ hydraulic reservoir housing 20 supporting the flexible membrane 168 is vented to the atmosphere by means of a vent hole 174. To permit access to the interior of the flexible membrane 168 for re-filling and like'purposes, a suitable passageway 176 is provided within the plug housing 169 and is closed by a threaded plug 178.
As previously indicated, the throttle valve 57 is actuated by downward movement of the treadle 14. Whlle the design of the treadle 14 may, of course, be varied, it is preferable that the treadle 14 be pivotally mounted or sup-ported at a point intermediate the ends of the hydraulic pump. Treadle 14 is shown in FIGS, 1 and 2 as i'ncluding a pair of downwardly extending lobes 180 and 182 at its opposite sides, these lobes including bores therein and being respectively pivotably supported by a cylindrical shaft portion 181 of the cylindrical valve housing 151 and by the cylindrical shaft portion of the cylindrical sleeve 183 whereby the treadle 14 is supported for pivotal move-ment about a horizontal axis. In its preferred form, the treadle 14 is of 20 integral one-piece construction and has a longitudinally rearwardly extending treadle portion 184 in turn having an end 120 positionable above the upwardly projecting end 59 of the'throttle valve 57 to permit actuation of the throttle - valve 57 upon downward application of pressure upon treadle portion 184.
The treadle 14 also includes a pair of forwardly and upwardly directed side ' arms 186 and 188 joined at their upper or forward end by a cross piece 190.
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Hydraulic Pressure :Release Mechanism To release the pressure developed in ~he high pressure hydraulic output passage 141 upon completion of the desired work, a release valve assembly 200 (FIGS. 6-8) is provided, operable by means of the treadle 1 for providing fluid communication between the output passage 141 and the .
- ~ hydraulic reservoir 132. A threaded va.lve housing 192 is threadably removably secured within a threaded bore 194 in the hydraulic valve block 22, and the valve housing 192 includes a central concentric stepped bore 196 therein communicating with the output passage 141.through a .
. . . . .
series of passages 197 (FIG. 3), 198, and 199 (FIG. 7). The bore 196 - .
houses a reciprocable plunger 204 and a spring biased check ball 206 which is rece;vable against a removable valve seat 208 and biased thereaga~nst , by a spring 210. The reciprocal plunger 204 is biased away from the ball 206 by a spring 215 in turn supported against valve seat 208. The :;.
fluid passage 199 which is in communication with the putput passage 141 by means of passages 197 and 198 is also in communication with an annular ;~
chamber 212 of the stepped bore 196. Due to the high hydraulic fluid pressures created within the output passage 141 and consequently within ~ ~ .
the chamber 212, the check ball 206 is forced against the seat 208 with . , .
substantial force. It is desirable, however, that the plunger 204 be easily 20 movable to unseat the ball 206 in order to release fluid pressure in the output passage 1~1, i. e., to permit fluid flow from the chamber 212 through the bore 214 in the seat 208 and consequently through the passage 216 and through a passage 2i8 into the reservoir 132. To thus facilitate reciproca-. tion of the plunger 209~ and movement of the ball 206 away :Erom valve seat 208, the valve housing 192 includes a continually open passage 220, through the valve hous;ng and spaced radially. o~twardly from the bore 196, .and i .,........ ~
-connecting the chamber 212 with an annular chamber 222 in the stepped bore 196 and surrounding the plunger 204 intermediate its ends. Furthermore, the plunger 204 is provided with a stepped configuration and an annular shoulder 224 adjacent the annular chamber 222. The differences between the effective cross sectional area of the shoulder 224 and the effective cross sectional area of the bore 214 is slight. Thus, the force on the ball 206 and the plunger 204 will be substantially baLanced and the necessary downward force on the plunger 204, which is necessary to force the ball 206 away from the seat 208 ~o permit fluid flow through the passage 214, wilL
be relatively small. In order to further provide means for easy manipula-tion of the plunger 204, the upper end of the plunger supports a roller 228 receivable against a curved cam surface 230 comprising an integral config-uration of the lower portion of the treadle 14. The curved cam surface 230 is particularly provided with a configuration such that the wedge angle between the cam surface and the roller 228 is very slight when the cam surface 230 and plunger 204 are in the position shown in FIG. 6. ~ Pivotal movement of the treadle 14 in the counterclockwise direction as seen in ~IGS. 6 and 7 will generate a downward force on the plunger 204 whereby the check ball 206 can be biased away from the seat 208 and hydraulic fluid caused to return to the reservoir 132. As the treadle 14 is further ;
depressed and cam surface 230 moves relative to the plunger 204 the - wedge angle increases. This construction facilitates substantial reciprocal travel of the valve plunger 204 once the ball 206 has been unseated thereby facilitating increased fluid flow back to the reservoir once the ball 206 has been unseated.
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SUM~RY OF THE INVENTION
The present invention provides an improved fluid operated hydraulic power unit having an improved hydraulic fluid release means for permitting return flow of hydraulic fluid from a hydraulic tool back to the reservoir of the power unit and having the advantages of being easily manually operable and providing a smooth fluid flow.
The invention comprises in a fluid actuated hydraulic pump: a body and including a motor chamber formed in one end of said body, and a hydraulic reservoir formed in the other end of said body and axially aligned with said motor chamber, means for pumping hydraulic fluid under pressure from said reservoir, said means for pumping including a hydraulic valve block disposed in axial alignment between said motor chamber and said reservoir, said valve block having an output passage for directing fluid under pressure from said pump to a point of use, a release passage from said . output passage to a point of pressure relief, and means for controlling fluid . flow from said output passage through said release passage, said means for .i controlling including a release valve assembly having opposite ends and .. I .
positioned in a valve bore in said hydraulic valve block, said release valve assembly having a reciprocable plunger, a valve seat between said output : :~
;: 20 passage and said release passage, a check ball engageable with said plunger, :~
. a biasing spring for urging said check ball against said valve seat, said ~ .
check ball being movable by said plunger from a first seated position wherein . fluid communication between said output passage and said release passage is prevented to a second unseated position for causing fluid communication .
:~ between said output passage and said release passage, means for selectively .
moving said plunger, and means for applying fluid pressure force on said reciprocable plunger for biasing said check ball toward said second unseated : : :
position, said means for applying fluid pressure force on said reciprocable plunger including a continually open hydraulic fluid passage from said out- :
put passage to said release passage, said open hydraulic fluid passage .; located radially outwardly of said valve bore. ~:
In the disclosed embodiment, the hydraulic pump includes a ~ .
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reciprocable hydraulic fluid pumping piston in turn driven by a piston of a fluid motor positioned adjacent to and in axial alignment with the hydraulic pump. The hydraulic fluid reservoir is also positioned abutting the hydraulic pump opposite the fluid motor. The hydraulic pump includes an output passage connectable to a hydraulic tool whereby hydraulic pressure developed by the hydraulic fluid pumping piston can be delivered to the tool, and also includes a release passage between the output passage and the reservoir to permit return of hydraulic fluid from the hydraulic tool. A
check valve, including a spring biased check ball, is disposed between the output passage and the release passage to releasably restrict the fluid flow i therethrough. In order to provide means for moving the check ball off of the check valve seat to permit fluid flow from the output passage to the release passage, a release valve plunger is disposed in a valve bore and has an end engageable against the check ball. The opposite end of the release valve plunger ends outwardly from the hydraulic pump and is engaged by a curved camming surface of a pivotable treadle. The release valve plunger is also provided with a roller at its outwardly extending end for engagement against the camming surface.
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The treadle is pivotably moveable such that the camming surface will engage the roller of the release valve plunger and cause axial movement of the release valve plunger whereby the opposite end of the release valve plunger can engage the check ball to move it away from its valve seat thereby permitting fluid flow from the output passage to the release passage.
In order to facilitate movement of the release valve plunger and the check ball with the application of only a relatively small axial force on the release valve plunger, means are provided for applying an axial fluid pres-sure force on the release valve plunger biasing the release valve plunger 10 toward the check ball to thereby substantially balance the force on the check ball forcing it against its valve seat. ~ continually open fluid passage disposed radially outwardly from the release valve provides fluid communi-cation from the output passage to an annular chamber surrounding the release valve bore and intermediate its ends whereby fluid pressure in the output passage is conve~red to the annular chamber. The release valve plunger is provided with a shoulder adjacent the annular chamber whereby :fluid pressure in the annular chamber generates an axial force on the release valve plunger toward the check ball, The effective cross-sectional area of the shoulder is slightly less than the effective cross-sectional area 20 of the bore of the valve seat whereby the forces on the release valve plunger and on the check ball, caused by fluid pressure in the output passage, are nearly equal and only a relatively small axial force on the release valve plunger is needed to move the check ball away from the valve seat.
The axial force on the release valve plunger necessary to unseat the check ball and open the check valve is applied by downward force of the treadle camming surface on the plunger roller, The camming surface i`
is particularly constructed to have a very slight wedge angLe at that part ~
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of the camming surface first contacting the release valve plunger roller whereby initial relative movement of the camming surface causes only a slight axial movement of the plunger. The wedge angle of the camming surface increases relative to its length, however, whereby further relative movement of the camming surface and roller results in greater axial movement of the plunger. Thus the relative shape of the camming surface facilitates substantial movement of the release valve plunger and check ball and increased fluid flow through the release passage once fluid flow through the release passage has been initiated and facilitates a smooth 10 increase in the rate of fluid flow from the hydraulic tool to the reservoir.
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BiRIEF DESCRIPTION OF THE DRAWINGS
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:; FIGURE 1 is a side elevation view of a fluid actuated hydraulic power unit of the present invention; . :
FIGURE 2 is an end elevation view of the power unit shown in FIG. 1;
FIGURE 3 is a cross-sectional plan view of the power unit shown ~: :
in FIG. 1 and is taken generally along line 3-3 in FIG. 1;
-: FIGURE 4 is a partial cross-sectional plan view similar to ~IG. 3 ::~
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:~ but distorted to show the air motor throttle valve generally in a side eleva- ~ ~ ~
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; ~ tion cross-section and showing the air piston of the air motor in- its fully ~ ~ ;
extended position;
FIGURE 5is a view similar to FIG. 4 but showing the air piston in a retracted poaition FIGURE 6 i9 an enlarged partial view of the power unit shown in FIG. 1 with portions cut away in the intere~st of clarity FIGURE 7 is a view similar to FIG. 6 but showing the hydraulic .` : fluid release plunger in a fluid release position; and - -. .
FIGURE 8 is an enlarged view of the hydraulic fluid release plunger shown in FIG, 7.
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Referring to the drawings, the power unit shown therein as embody-ing the invention comprises, in general, a unitary body 10 supported by a base 12 and having an actuating lever or treadle 14 pivoted thereon. The body 10 includes a fluid or air motor portion 16 closed at one end- by an air motor valve block 18 and having a hydraulic reservoir housing 20 e~tending from its opposite end and a hydraulic pump valve block 22 interposed between .
the air motor 16 and the hydraulic reservoir housing 20. The body 10 is of generally cylindrical shape, and the air motor portion 16, air motor valve 1~ block 18, hydraulic reservoir housing 20, and hydraulic pump valve block 22 are in axial alignment, The air motor 16 and the air motor valve block 18 are shown as being comprised from plastic and can be advantageously formed by inJection molding, however, a plurality of other materials such as die ....
cast aluminum could be used. The air motor 16 is secured to the ~ .
hyd.raulic pump valve block 22 by a restrainlng band 24 which can be received around an end portion 17 of air motor 16 whereby that end OI the plastic ~ . air motor can be clamped against a projecting annular end 26 of the hydraulic valve block 22 by means of a tightening screw 28. The hydraulic reservoir housing 20 is comprised in part of a cylindrical sleeve 21 whic~l includes an 20 open end which is received around an end 27 of the hydraulic valve block 22 and secured thereto by screws 30.
. Live air or other pressurized fluid :Erom a suitable source 32 (FIG. 3) is admitted through a conduit 33 to the air motor valve block 18 by means of an air inlet coupling 34, which is threadably received within a bore 35 in the valve block 1~, and high pressure hydraulic fluid is discharged from the hydraulic pump valve block 22 through a high pressure pump outlet swivel . . .
coupling 36, Air Motor . ~ ;
Referring to the air motor 16 and air motor valve block 18 shown in . -FIGS. 3-6, air from the supply source 32 is intended to pass through the àir inlet coupling 34 and through an air filter 38 threadably journalled ~: :
therein and within the bore 35. The flow of air through the air inlet coupling 3g is governed by a check valve poppet 40 which includes a flange 4 2 at one end receivable against a valve seat 44 (FIG. 4) to prevent fluid flow into the air motor. The check vall7e poppet 40 is a~:ially slideably supported in an ~ :
axial bore 46 in the air motor valve block 18 and is co-axial with the longi~
10 tudinal axis of the air motor 16, hydraulic reservoir housing 20, and hydraulic valve block 22, and the axial position of the check valve poppet 40 .
is governed by a spring biased shuttle valve 48 as will be described herein- .
. - ~ a~ter. When the check valve poppet 40 is in a position to permit air flow .
into the bore 96 (FIG. 3), the air will then flow th~ ugh a supply passage 50 ~FIG, 5) in the air valve block 18 to a cylindrical bore 52 housing an actuating ..
throttle valve assembly 54. The actuati.ng throttle valve assembly 54 is . slideably received in the bore 52 and fluid-tight relationship is maintained by resilient O-ring seals 56. The actuating throttle valve asse~bly 54 includes a generally cylindrical valve body 55 and a slideable tnrottle valve poppet 57 20 which is axially movable within a bore 58 in the valve body 55 and which in-cludes a flange 60 at one end normally seated against a valve seat 62 of the '. valve body 55 and biased toward a fluid flow restricting position by air pres- -.
sure in the supply passage 50O The valve body 55 also includes a port 6 ' ~ .
therethrough in open communication with the axial bore 58 in the valve body 55 .; and intended to facilitate air flow through an axial supply passage 66 in the air valve block 18 and air motor 16 whereby air can be supplied to the air . .
motor displacement chamber 68.
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The air motor portion 16 also includes an axialLy aligned stepped bore or cylinder 70 adjacent its end wall 71, the bore 70 being defined by a generall~- tubular axially projecting sleeve 72 which is receivable in fluid-tight relationship within the air motor valve block 18. The stepped bore 70 slideably houses the shuttLe valve poppet 4B which is in turn functional to ! permit exhaust from the chamber 68 through an exhaust port 85 and into an annular expansion chamber 87 in the air motor valve block 18 and finally through exhaust ports 74 in the air motor valve block 18. The shuttle valve poppet 48 is positioned in axial alignment wiith and can be secured to the -~
check valve poppet 40 by a screw 83 received through shuttle valve poppet 48 ~ ..
and threadably received in a bore 40b in the check valve poppet 40 such that the shuttle valve poppet 48 is also functional to control axial movement of the check valve poppet 40. The shuttle valve poppet 48 also includes a molded resilient piston portion 75 at one end and axially slideable within the bore 70. A coil spring 76 is positioned between an annular inwardly . ~ . proJecting flange 78 of the air motor 16 a~d the piston portion 75 of the - shuttle valve poppet 48. A circular disc-like resilient seal 82 is secured by means of a backup washer 82a and a screw 83 to the end of the shuttle valve poppet 48 opposite the piston 75 and is normally received against a . 20 seat 84 of the annular flange 78 to prevent exhaust of air from the chamber ~ 68 through the bore 70.
.;. The air motor 16 also includes a cylinder 86 which defines the air motor displacement chamber 68 &nd which receives an axially movable piston 90 therein. A fluid-tight seal is maintained between the cylinder walls of the cylinder 86 and the periphery of the piston 90 by a resilient seal 108.
In order to permit reciprocation of the piston 90 in the displacement cham-ber 68, fluid communication between the ambient atmosphere and that portion .
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includes an annular groove 110 surrounding its circumference and a plurality - ~ of ports 112 to provide communication between the displacement chamber 68 and the groove 110 and to permit air flow through the port 92a as the piston 90 reaches the end of its forward stroke.
The displacement chamber 68 is also vented through a port 92 which is remote from the air motor valve block 18 and in communication with the bore 70 through a passage 94, and through a passage 96 in the air motor ~valve block 18. The port 92 is positioned such that it is adapted to be un-covered by the air motor piston 90 only when the piston 90 reaches the end 10 of its forward stroke.
Seated against the front face of thè air motor piston 90 IS a small diameter hydraulic fluid pump piston 98 slideably receivable in a cylinder 99 and operable to pump hydraulic fluid through passages in the hydraulic block 22 as will hereinafter more fully appear. The rear of the hydraulic pump piston 98 extends into the air motor displacement chamber 68 and is formed with an enlarged head 100 having a rounded or spherical bearing surface 101 urged against a complementary rounded surface 102 in the face .~
of the piston 90 hy a spring 104 compressed between and seated against the rear of the hydraulic valve block 22 and an annular disc 106 supported by 20 the pump piston 98 and adjacent to its head end l00.
Air Motor Operation In operation and assuming that the piston 90 begins its reciprocal -.~: . : :
:~ movement in the position shown in FIG. 3, wherein the force of the spring 104 urges the piston 90 against the shuttle valve poppet 48 thereby causing .
the check valve poppet 40 to move axially in bore 46 and the flange 42 thereof . ~
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to be movecl atvay from the valve seat 44 whereby air can pass through the bore 46 into the passageway 50 (FIG. 4). To cause actuation of the air motor, the operator depresses treadle 14 such that the tab 120 (FIG. 6) at the end of the treadle 14 engages the upwardly projecting end 59 of the actuating throttle valve poppet 57 thereby moving the flange 60 away from the valve seat 62 and permitting compressed air to flow from supply passagc ~0 through passages 64 and 66 into the cylinder cavity 68. The resulting air pressure in cavity 68 will force air piston 90 and the hydraulic fluid piston 98to the position shown in FIG. 4 thereby providing a hydraulic fluid pumping : 10 effect. Such movement of the piston 90 to the end of its stroke will uncover :: the port 92 thereby permitting compressed air in the displacement chamber 68 to communicate through passages 94 and 96 with the cylinder 70. The com-pressed air flowing through passages 94 and 96 into the cylinder 70 will cause the piston portion 75 of the shuttle valve poppet 48 and the check valve poppet 40 attached thereto to move to the left to the position shown in FIG. 4 agaiQst the force of the spring 76, Movement of the piston portion 75 to the position shown in FIG. 4 causes the flange 42 of the check valve poppet 40 to be received aga~inst the seat 44 thereby restricting further flow of air through the passage 50 into the air motor 16.
When the piston portion 75 of the shuttle valve 48 moves to the position shown in FIG. 4, the dise 82 also moves away from the seal 84 thereby permitting the compressed air within the displacement chamber 68 to exhaust through the bore 7d, through the exhaust port 85, into the annular expansion chamber 87 containing a number of baffles 89, and finally through the plurality of small exhaust passages 74.
.~s the compressed air is thus exhausted from the displacement chamber 68, the spring 104 forces the piston 90 to return toward its original position as shown in FIG. 3. As shown in FIG. 5, as the piston 9o nears its original position, the piston 90 contacts the screw 83 and backup washer 82a thereby causing the shuttle valve poppet 48 and the check valve poppet 40 to be forced to the right and continued movement of the piston 90 cause3 the resilient disc 82 to be received in sealing engagement against the seal 84 to prevent further exhaust flow from chamber 68 and simultaneously ~-forces the flange 42 of the check valve poppet 40 away from the seat 44 10 . to permit air flow from the supply source 32 into the passage 50. Further- ~ .
~ more, it will thus be appreciated that before the piston 90 reach0s the end ,l ~ of its return stroke, the flange 42 of the chec~ valve poppet 40 is forced away from the seat 44 sufficiently that air flow through the passage 50 and into the displacement chamber 68 will effect damping of the return stroke of the piston 90. As long as the treadle 14 is depressed and the actuating throttle valve 57 is open, whereby passage 50 and the passages 64 and 66 are in communication, the air motor will continue to pump in a similar .~ . fashion as that described above until hydraulic fluid pressure in the cylinder .,. ,. . : :
99 reaches a desired level.
: 20 Hydraulic Fluid Pump -~
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. In this manner, the hydraulic pump piston 98 is thus caused to recip-rocate within the hydrau~ic pump cylinder 99 by the combined action of the .
air motor piston 90 and the return spring 104. While the hydraulic pump cylinder 99 may be formed directly in the hydraulic pump valve block 22, it is preferably formed as shown in a readily removable and replaceable : .
cartridge 124 which is threadably received within a bore 125 in the hydraulic ` .
. valve block 22. Fluid-tight relationship between the hydraulic piston 98 ~ :
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: :-and cylinder 99 is maintained by a seal 126 secured within the cartridge 124 by a backup ring 128 and a snap ring 130. The hydraulic circuitry of the hydraulic pump is encased within the hydraulic valve block 22 (FIG. 3) and comprises in part a suction or supply passage 131 extending from the hydraulic r eservoir 132 within the hydraulic reservoir housing 2~ past a spring biased ball check valve 134 to the hydraulic pressure chamber 135.
The ball check valve 134 includes a ball 136 being seated against a removable seat 138 to close the passage 131 during the forward stroke of the piston 98 and being unseated to open the passage 131 during the return or suction stroke : . 10 of the piston 98. The ball 136 is biased against the seat 138 by a spring 139 supported by the end of the replaceable cartridge 124. The passage 131 ex-tends through a generally hollow cylindrical hydraulic fluid filter 137 which is threadably secured within a bore 137a in the hydraulic valve bloc~ 22 and which extends into the reservoir 132, The fluid filter 137 is constructed from a material which permits hydraulic fluid to flow through it but which prevents impurities from entering the pumping chamber 135.
The hydraulic valve block 22 also includes a high pressure discharge Gr outlet passageway 141 past a one-way ball check valve 142. The ball check valve 142 is comprised of a valve seat 143 threadably and removably secured within a bore 144 in the hydraulic valve block 22 and a check ball 146 biased against the valve seat 143 by a spring 147. The outlet passage 141 is defined : by an axially extending bore 140 through the valve seat 193 and by a longitu-dinal bore through a cylindrical sleeve 183 which has one end threadably secured within the bore 144 of the valve block 22 and another end supporting a freely rotatable coupling member 148 of the swivel coupling 36. The coupling member 148 includes a stepped central bore 149 therein in communication with the passage 141, the central bore 149 including a .
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:. , . ' ' ' " ' ' threaded end 1a~)a for threadably receiving a hydraulic hose or the like. A
fluid-tight seal is maintained between the coupling member 148 and the cylindrical sleeve 183 by a resilient O-ring 150 and relative rotation of the -coupling 148 around the end of the sleeve 183 is facilitated by a pair of retaining pins 152 extending through the coupling member 148 and receivable in a circumferential groove 152a in the sleeve 183.
Also formed in the valve block 22 is a relief valve assembly 150 comprising a generally cylindrical valve housing 151 threadably secured within a bore 152 in the valve block 22, the relief valve assembly 150 intended to provide communication of hydraulic fluid between the hydraulic pressure chamber 135 and the reservoir 132 in the event the fLuid pressure in the pressure chamber 135 becomes too great. A port 154 in the valve block 22 extends from the hydraulic pressure chamber 135 into the bore 152 and a similar but transverse bore 156 extends from the bore 152 into the hydraulic reservoir 132. The cylindrical valve housing includes a central chamber 153 in communication with the port 154 through a bore 155 and simi-larly in communication with transverse bore 156 through a bore 159, howeverg fluid flow therethrough is prevented by means of a spring biasèd check vaLve - 157 in the valve housing 151, the check valve 157 being comprised of a ball 158 received against a seat 160 and biased thereagainst by a spring 162 and a ball support member 164. The biasing force of the spring 162 can be -adjusted by an accessible screw 166.
The oil in the reservoir 132 is confined within a container formed by a flexible membrane or bladder 168 having a generally cylindrical shape and having one end reversed inwardly and received in fluid-tight relationship in a circumferential groove 167 around a cylindrical plug housing 169 thread- `
ably received in a bore 171 in the end of the hydraulic reservoir housing 20.
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The other encl of the container 168 is secured between the wall of the hydraulic reservoir housing 20 and the circumferential periphery of the valve block 22 and includes a circumferential bead 170 received within a circumferential groove 172 around the hydraulic valve block 22. The chamber 173 of the `:~ hydraulic reservoir housing 20 supporting the flexible membrane 168 is vented to the atmosphere by means of a vent hole 174. To permit access to the interior of the flexible membrane 168 for re-filling and like'purposes, a suitable passageway 176 is provided within the plug housing 169 and is closed by a threaded plug 178.
As previously indicated, the throttle valve 57 is actuated by downward movement of the treadle 14. Whlle the design of the treadle 14 may, of course, be varied, it is preferable that the treadle 14 be pivotally mounted or sup-ported at a point intermediate the ends of the hydraulic pump. Treadle 14 is shown in FIGS, 1 and 2 as i'ncluding a pair of downwardly extending lobes 180 and 182 at its opposite sides, these lobes including bores therein and being respectively pivotably supported by a cylindrical shaft portion 181 of the cylindrical valve housing 151 and by the cylindrical shaft portion of the cylindrical sleeve 183 whereby the treadle 14 is supported for pivotal move-ment about a horizontal axis. In its preferred form, the treadle 14 is of 20 integral one-piece construction and has a longitudinally rearwardly extending treadle portion 184 in turn having an end 120 positionable above the upwardly projecting end 59 of the'throttle valve 57 to permit actuation of the throttle - valve 57 upon downward application of pressure upon treadle portion 184.
The treadle 14 also includes a pair of forwardly and upwardly directed side ' arms 186 and 188 joined at their upper or forward end by a cross piece 190.
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Hydraulic Pressure :Release Mechanism To release the pressure developed in ~he high pressure hydraulic output passage 141 upon completion of the desired work, a release valve assembly 200 (FIGS. 6-8) is provided, operable by means of the treadle 1 for providing fluid communication between the output passage 141 and the .
- ~ hydraulic reservoir 132. A threaded va.lve housing 192 is threadably removably secured within a threaded bore 194 in the hydraulic valve block 22, and the valve housing 192 includes a central concentric stepped bore 196 therein communicating with the output passage 141.through a .
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series of passages 197 (FIG. 3), 198, and 199 (FIG. 7). The bore 196 - .
houses a reciprocable plunger 204 and a spring biased check ball 206 which is rece;vable against a removable valve seat 208 and biased thereaga~nst , by a spring 210. The reciprocal plunger 204 is biased away from the ball 206 by a spring 215 in turn supported against valve seat 208. The :;.
fluid passage 199 which is in communication with the putput passage 141 by means of passages 197 and 198 is also in communication with an annular ;~
chamber 212 of the stepped bore 196. Due to the high hydraulic fluid pressures created within the output passage 141 and consequently within ~ ~ .
the chamber 212, the check ball 206 is forced against the seat 208 with . , .
substantial force. It is desirable, however, that the plunger 204 be easily 20 movable to unseat the ball 206 in order to release fluid pressure in the output passage 1~1, i. e., to permit fluid flow from the chamber 212 through the bore 214 in the seat 208 and consequently through the passage 216 and through a passage 2i8 into the reservoir 132. To thus facilitate reciproca-. tion of the plunger 209~ and movement of the ball 206 away :Erom valve seat 208, the valve housing 192 includes a continually open passage 220, through the valve hous;ng and spaced radially. o~twardly from the bore 196, .and i .,........ ~
-connecting the chamber 212 with an annular chamber 222 in the stepped bore 196 and surrounding the plunger 204 intermediate its ends. Furthermore, the plunger 204 is provided with a stepped configuration and an annular shoulder 224 adjacent the annular chamber 222. The differences between the effective cross sectional area of the shoulder 224 and the effective cross sectional area of the bore 214 is slight. Thus, the force on the ball 206 and the plunger 204 will be substantially baLanced and the necessary downward force on the plunger 204, which is necessary to force the ball 206 away from the seat 208 ~o permit fluid flow through the passage 214, wilL
be relatively small. In order to further provide means for easy manipula-tion of the plunger 204, the upper end of the plunger supports a roller 228 receivable against a curved cam surface 230 comprising an integral config-uration of the lower portion of the treadle 14. The curved cam surface 230 is particularly provided with a configuration such that the wedge angle between the cam surface and the roller 228 is very slight when the cam surface 230 and plunger 204 are in the position shown in FIG. 6. ~ Pivotal movement of the treadle 14 in the counterclockwise direction as seen in ~IGS. 6 and 7 will generate a downward force on the plunger 204 whereby the check ball 206 can be biased away from the seat 208 and hydraulic fluid caused to return to the reservoir 132. As the treadle 14 is further ;
depressed and cam surface 230 moves relative to the plunger 204 the - wedge angle increases. This construction facilitates substantial reciprocal travel of the valve plunger 204 once the ball 206 has been unseated thereby facilitating increased fluid flow back to the reservoir once the ball 206 has been unseated.
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Claims (11)
1. In a fluid actuated hydraulic pump: a body and including a motor chamber formed in one end of said body, and a hydraulic reservoir formed in the other end of said body and axially aligned with said motor chamber, means for pumping hydraulic fluid under pressure from said reservoir, said means for pumping including a hydraulic valve block disposed in axial alignment between said motor chamber and said reservoir, said valve block having an output passage for directing fluid under pressure from said pump to a point of use, a release passage from said output passage to a point of pressure relief, and means for controlling fluid flow from said output passage through said release passage, said means for controlling including a release valve assembly having opposite ends and positioned in a valve bore in said hydraulic valve block, said release valve assembly having a reciprocable plunger, a valve seat between said output passage and said release passage, a check ball engageable with said plunger, a biasing spring for urging said check ball against said valve seat, said check ball being movable by said plunger from a first seated position wherein fluid communication between said output passage and said release passage is prevented to a second unseated posi-tion for causing fluid communication between said output passage and said release passage, means for selectively moving said plunger, and means for applying fluid pressure force on said reciprocable plunger for biasing said check ball toward said second unseated position, said means for applying fluid pres-sure force on said reciprocable plunger including a continually open hydraulic fluid passage from said output passage to said release passage, said open hydraulic fluid passage located radially outwardly of said valve bore.
2. The fluid actuated hydraulic pump set forth in Claim 1 wherein said reciprocable plunger includes an end projecting from said hydraulic valve block, and wherein said means for moving said plunger includes a lever shiftably supported by said unitary body and including a cam surface engagable against said end of said plunger for shifting said reciprocable plunger against said ball to move the latter to its second unseated position to cause fluid flow through said release passage.
3. The fluid actuated hydraulic pump set forth in Claim 2 wherein said end of said plunger supports a roller engagable against said cam surface.
4. The fluid actuated hydraulic pump set forth in Claim 1 wherein said reciprocable plunger includes an annular shoulder intermediate its ends, wherein said valve bore includes opposite ends and an annular chamber intermediate its ends, wherein said continually open hydraulic fluid passage communicates with said annular chamber, and wherein said annular shoulder is between said annular chamber and said valve seat whereby fluid pressure in said annular chamber applies a force on said annular shoulder to move said plunger toward said valve seat.
5. A fluid actuated hydraulic pump having a body and comprising:
a motor cylinder formed in one end of said body and defining a chamber therein;
a hydraulic reservoir in the other end of said body and axially aligned with said motor cylinder;
a hydraulic pumping means between said hydraulic reservoir and said motor cylinder; and a motor piston reciprocable in said motor cylinder and operably connected to said hydraulic pumping means for driving said pumping means;
said hydraulic pumping means including a hydraulic valve block, said hydraulic valve block including a pumping chamber opening to one side of said valve block, a hydraulic fluid inlet passage between said hydraulic reservoir and said pumping chamber for providing fluid communication therebetween, an outlet port, an outlet passage extending between said pumping chamber and said outlet port, a release passage between said outlet passage and said hydraulic reservoir for permitting fluid communication therebetween, and means for controlling fluid flow from said outlet passage to said release passage, said means for controlling including a release valve assembly having opposite ends and positioned in a valve bore in said hydraulic valve block, said release valve assembly having a reciprocable plunger, a valve seat between said output passage and said release passage, a check ball engagable with said plunger, a biasing spring for urging said check ball against said valve seat, said check ball being movable by said plunger from a first seated position wherein fluid communication between said output passage and said release passage is prevented to a second unseated position for causing fluid communication between said output passage and said release passage, means for selectively moving said plunger, and means for applying fluid pressure force on said reciprocable plunger for biasing said check ball toward said second unseated position, said means for applying fluid pressure force on said reciprocable plunger including a continually open hydraulic fluid passage from said output passage to said valve bore, said open hydraulic fluid passage located radially outwardly of said release valve bore.
a motor cylinder formed in one end of said body and defining a chamber therein;
a hydraulic reservoir in the other end of said body and axially aligned with said motor cylinder;
a hydraulic pumping means between said hydraulic reservoir and said motor cylinder; and a motor piston reciprocable in said motor cylinder and operably connected to said hydraulic pumping means for driving said pumping means;
said hydraulic pumping means including a hydraulic valve block, said hydraulic valve block including a pumping chamber opening to one side of said valve block, a hydraulic fluid inlet passage between said hydraulic reservoir and said pumping chamber for providing fluid communication therebetween, an outlet port, an outlet passage extending between said pumping chamber and said outlet port, a release passage between said outlet passage and said hydraulic reservoir for permitting fluid communication therebetween, and means for controlling fluid flow from said outlet passage to said release passage, said means for controlling including a release valve assembly having opposite ends and positioned in a valve bore in said hydraulic valve block, said release valve assembly having a reciprocable plunger, a valve seat between said output passage and said release passage, a check ball engagable with said plunger, a biasing spring for urging said check ball against said valve seat, said check ball being movable by said plunger from a first seated position wherein fluid communication between said output passage and said release passage is prevented to a second unseated position for causing fluid communication between said output passage and said release passage, means for selectively moving said plunger, and means for applying fluid pressure force on said reciprocable plunger for biasing said check ball toward said second unseated position, said means for applying fluid pressure force on said reciprocable plunger including a continually open hydraulic fluid passage from said output passage to said valve bore, said open hydraulic fluid passage located radially outwardly of said release valve bore.
6. The fluid actuated hydraulic pump set forth in Claim 5 wherein said reciprocable plunger includes an end projecting from said hydraulic valve block, and wherein said means for moving said plunger includes a lever shiftably supported by said unitary body and including a cam surface engagable against said end of said plunger for shifting said reciprocable plunger against said ball to move the latter to its second unseated position to cause fluid flow through said release passage.
7. The fluid actuated hydraulic pump set forth in Claim 6 wherein said end of said projection supports a roller engagable against said cam surface.
8. The fluid actuated hydraulic pump set forth in Claim 5 wherein said reciprocable plunger includes an annular shoulder intermediate its ends, wherein said valve bore includes an annular chamber intermediate its ends, wherein said continually open hydraulic fluid passage communicates with said annular chamber, and wherein said annular shoulder is between said annular chamber and said valve seat whereby fluid pressure in said annular chamber applies a force on said annular shoulder to move said plunger toward said valve seat.
9. The fluid actuated hydraulic pump set forth in Claim 7 wherein said reciprocable release valve includes an annular shoulder intermediate its ends and wherein said valve bore includes an annular chamber intermediate its ends, said continually open hydraulic fluid passage communicating with said annular chamber and said annular shoulder being between said annular chamber and said valve seat whereby fluid pressure in said annular chamber applies a force on said annular shoulder toward said valve seat.
10. The fluid actuated hydraulic pump set forth in Claim 3 wherein said cam surface is curved.
11. The fluid actuated hydraulic pump set forth in Claim 1 wherein said plunger has an effective area against which fluid pressure force is applied which is smaller than the effective area of said ball against which fluid pressure is applied whereby a differential force exists which tends to keep said ball on said valve seat.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US71774976A | 1976-08-25 | 1976-08-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063871A true CA1063871A (en) | 1979-10-09 |
Family
ID=24883307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,992A Expired CA1063871A (en) | 1976-08-25 | 1977-08-03 | Fluid operated hydraulic pump including an improved hydraulic fluid pressure release assembly |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5327105A (en) |
| AU (1) | AU2749777A (en) |
| BR (1) | BR7705349A (en) |
| CA (1) | CA1063871A (en) |
| DE (1) | DE2738177A1 (en) |
| FR (1) | FR2363008A1 (en) |
| GB (1) | GB1547675A (en) |
| IT (1) | IT1079439B (en) |
| MX (1) | MX145712A (en) |
| SE (1) | SE7709323L (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6047479B2 (en) * | 1979-09-18 | 1985-10-22 | 有光工業株式会社 | Multiple reciprocating pump |
| JPS6110304A (en) * | 1984-06-26 | 1986-01-17 | Fujitsu Ten Ltd | Distortion preventing circuit |
| JPS6335311U (en) * | 1986-08-25 | 1988-03-07 | ||
| SE467165B (en) * | 1988-10-28 | 1992-06-01 | Nike Ab | PRESSURE AIR PUMP DEVICE |
| DE19714100C1 (en) * | 1997-04-05 | 1998-03-05 | Juergen Dr Ing Berbuer | Pump driven by compressed air |
| US10456801B2 (en) * | 2017-01-26 | 2019-10-29 | Graco Minnesota Inc. | Material sprayer having sliding pump mounting |
-
1977
- 1977-08-01 AU AU27497/77A patent/AU2749777A/en active Pending
- 1977-08-03 CA CA283,992A patent/CA1063871A/en not_active Expired
- 1977-08-10 GB GB33515/77A patent/GB1547675A/en not_active Expired
- 1977-08-11 IT IT50651/77A patent/IT1079439B/en active
- 1977-08-12 BR BR7705349A patent/BR7705349A/en unknown
- 1977-08-18 SE SE7709323A patent/SE7709323L/en unknown
- 1977-08-23 MX MX170317A patent/MX145712A/en unknown
- 1977-08-24 FR FR7725868A patent/FR2363008A1/en not_active Withdrawn
- 1977-08-24 DE DE19772738177 patent/DE2738177A1/en not_active Ceased
- 1977-08-25 JP JP10217377A patent/JPS5327105A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2363008A1 (en) | 1978-03-24 |
| SE7709323L (en) | 1978-02-26 |
| IT1079439B (en) | 1985-05-13 |
| GB1547675A (en) | 1979-06-27 |
| DE2738177A1 (en) | 1978-03-02 |
| AU2749777A (en) | 1979-02-08 |
| JPS5327105A (en) | 1978-03-14 |
| MX145712A (en) | 1982-03-25 |
| BR7705349A (en) | 1978-05-23 |
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