US3402642A

US3402642A - Reciprocating valve and piston

Info

Publication number: US3402642A
Authority: US
Inventors: George J Van Hecke; Chirco Peter Roy
Original assignee: Huck Manufacturing Co
Current assignee: Huck Manufacturing Co
Priority date: 1965-10-23
Filing date: 1965-10-23
Publication date: 1968-09-24
Anticipated expiration: 1985-09-24
Also published as: GB1157897A; DE1550315A1

Description

Sept; 24, 71968 G. J. VAN HECKE ETAL 3,402,642

RECIPROCATING VALVE AND PISTON Filed 001:. 23, 1965 INVENTORS) Gearye I Van Hec'ke,

' Pefer Rqy Ckfrca United States Patent Oflice Patented Sept. 24, 1968 3,402,642 RECIPROCATING VALVE AND PISTON George J; Van Hecke, Detroit, and Peter Roy Chirco, Utica, Mich., assignors to' Huck Manufacturing Conrpauy, Detroit, Mich., a corporation of Michigan Filed on. 23, 1965, Ser. No. 503,701 14 Claims. 01. 91-329 ABSTRACT OF THE DISCLOSURE A two position reciprocatable valve for causing automatic' reciprocation of a piston.

The present invention relates to a valve construction, and more particularly to a two-position reciprocable valve.

The present invention deals with an air directional valve which, in the specific form shown and described, can be used in the multiple stroke rivet installation tool, shown and described in the copending application of George J, Van Hecke et al., Ser. No. 408,828, filed Nov. 4, 1964. In that particular application the air directional valve is utilized to reciprocate rapidly between two positions to alternate the flow of air to opposite sides of a pair of tandem pistons. In such an application it is important that the air directional valve not stall between positions whereby the reciprocation of the tandem pistons is stopped; it is also important that the amount of wear,

etc., on the air directional valve be minimized to insure a long life. Therefore, it is an object of the present invention to provide a novel valve.

' It is another object of the present invention to provide a novel two-position reciprocable valve.

It is another object of the present invention to provide a novel air directional valve specifically for use in apparatus such as shown and described in the above-noted copending patent application. I

It is still another object of the present invention to provide a novel valve adapted for rapid reciprocation between two positions.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawing, in which:

The drawing is a fragmentary view of a combination schematic and sectional representation of a portion of a power supply including a preferred form of the valve of the present invention.

Looking now to the drawing, a portion of a power supply is generally indicated by the numeral and is of the type shown in the above noted copending patent application. Since the specific details of the power supply 10 do not constitute a part of the present invention, and since all these details are not required for the understanding of the valve of the present invention, only those portions of the power supply 10 necessary to an understanding of the operation of the valve of the present invention have been shown for the purposes of simplicity. The power supply 10 includes a-housing member 12 which includes a pair of cylinders 14 and 16. Cylinders 14 and 16 are axially spaced and coaxially located and a throughbore 17 extends between the cylinders 14 and 16 and along the axis thereof, and a second through bore 18 extends between the cylinders14 and 16 and is axially offset from the central axis thereof. A pair of pistons 20 and 22 are located within the cylinders 14 and 16, respectively, and are connected together by a common shaft assembly 24 which has an intensifier piston 26 located generally midway therealong. Intensifier piston 24 is located in an enlarged portion 28 of the bore 17 to provide an output of intensified fluid pressure. A first passageway 30 connects the upper portion of the enlarged cylinder portion 28 and a second passageway 32 connects the lower end of the enlarged cylinder portion 28. A pair of ball check valves 34 and 36 are connected to the passage 30 in a manner such that on the downward stroke of the intensifier piston 26, fluid is drawn into the upper portion of the enlarged cylinder portion 28 through the check valve 36 to replenish that portion while intensified fluid is transmitted out through the passageway 32. On the upward stroke of the intensifier piston 26, the check valve 36 is closed and intensified fluid pressure is transmitted through the passageway 30 through the check valve 34, a pair of check valves similar to the Valves 34 and 36 can be provided to be operative with the passageway 32 whereby fluid pressure can be transmitted from the passageway 32 on a down stroke of the intensifier piston 26 and fluid can be transmitted to replenish the cylinder portion 28 upon an upward stroke of the intensifier piston 26. The remaining details of such a power supply 10 are included in the copending patent application previously noted.

As contemplated in the copending patent application previously noted, hydraulic pressure is obtained out from the passageways 30 and 32 through reciprocation of the intensifier piston 26 in response to reciprocation of the tandem pistons 20 and 22 which are actuated by pneumatic pressure. The upper or head end of the cylinder 14 is connected to a passage 38 while the upper or rod end of the cylinder 16 is connected to the same passage 38. Thus air under pressure can be transmitted to the passageway 38 to both the head end of the piston 20 and the rod end of the piston 22, thereby causing the tandem piston structure to be moved downwardly. A second passageway 40 communicates with the lower or rod end of the cylinder 14 and with the lower or head end (not shown) of the cylinder 16 such that upon application of air pressure to the passageway 40 pressure will be exerted both on the rod end of the piston 20 and the head end of the piston 22, causing the tandem piston structure to be moved upwardly. Air pressure is alternated between the

passages

38 and 40 such that when the one passageway is pressurized the other is open to exhaust or atmosphere to thereby permit the reciprocation of the tandem pistons 20 and 22. The connection of the

passageways

38 and 40 alternately to pressure and exhaust is effected by the air directional valve assembly 42, which is located matably within the bore -18 and includes a series of

annular grooves

46, 48, 50, .52 and 54 located in its outer surface. The grooves 46 and 54 are located at opposite extremities of the fixed body 44. The groove 46 is connected in communication with the through bore 56 by means of a pair of diametrically extending ports 58 and 60. The groove 48 communicates with the bore 56 by means of a diametrically extending port 62. The groove 50 is in communication with the bore 56 by means of a diametrically extending port 64. The groove 52 is in communication with the bore 56 by means of a diametrically extending port 66 and the groove 54 is in communication with the bore 56 by means of a pair of diametrically extending

ports

68 and 70. The annular groove 56 is connected to atmosphere by means of a passageway 72 in the housing member 12. While the annular groove 54 is in communication with amosphere by means of a passageway 74 in the housing member \12, the annular groove 50 is in communication with pressurized air by means of a passageway 76 in the housing member 12. The passageway '38, previously described, is in communication with the annular 'groove 52 by means of a passageway 78 in the housing member 12, while the passageway 40, previously described, is in communicat I: j 8,402,642

tion with the groove 48 bymeans of thep'assageway 80 in the housing member 14. i

The passageway 58 at the upper end of the body member 44 is defined in part by an enclosing cap member 82, which is located at the upper end of the bore 18' while the passageway 70 at the bottom end of the body member 44 is defined in part by a cap member 84 at the bottom or lower end of the bore 18. The caps 82 and 84 serve a purpose to be described.

'Caps 82 and 84 in general enclose the cavity defined by the through bore 56 in which is located a movable valve body member '86. The valve body member 86 is provided 'with a pair of cavities 88 and 90 which extend inwardly from opposite ends. An actuating pin member 92 extends through a bore 94 in the cap 82 and has at its inner end and within the cavity 88 a cup portion 96 which receives a coil spring member 98, which is precompressed to normally maintain the pin 92 in its outermost position against a retaining ring 100. Similarly, at the opposite end within the cavity '90 is located a pin 102 which extends outwardly through a bore 104 at the end of the cap 84. The pin .104 has a cup portion 106 located within the cavity 90 in which is housed a spring member 108 which is under a precompression to maintain the pin 102 in its outermost position against a retaining ring 110. The bore 56 has a pair of annular grooves 112 and 114 which have a radial cross section defining a portion of a circle. The movable body member 86 is provided with a ball detent assembly 116 which is located in a diametrically through bore 118. The ball detent assembly includes a ball bearing 120 and a cupmember 122 which has an end portion 124 which defines a portion of a sphere of a diameter similar to that of the ball bearing 120. A spring member 126 is located within the cup member 122 and is under precompression to exert a force against both the ball bearing 120 and a cup member 122 to maintain them separated. The movable body member 86 is provided with a pair of axially spaced, elongated

annular grooves

128 and 130 in its outer surface. The groove 128 is located at the upper half of the movable body member 86 and is provided of a length to be constantly in communication with the port 62 and hence passageway 80 and hence the connecting passageway 40. The annular groove 128 is provided to be of a length such that with the movable body member 86 in its uppermost position as shown in the drawing, the groove 128 will communicate with the through port 60 and hence with the annular groove 46, thence with the passageway 72 to connect thereby the passageway 40 to exhaust. Thus in the position as shown, the rod end of the piston and the head end of the piston 22 will be connected to exhaust. The annular groove 128 is of a sufficient length and is located such that with the valve body 86 moved downwardly in its lowermost position, the groove 128 will no longer communicate with the port 60 and hence will no longer communicate with the atmosphere through the passageway 72, but will be in a position in which it is then in communication with pressurized air via the passageway 76, the annular groove 50 and the port 64 whereby pressurized air is communicated to the passageway and to the rod endof the piston 20 and the head end of the piston 22 to cause the tandem piston assembly to move upwardly. The annular groove 130 is constantly in communication with the passageway38 via the passageway 78, the annular groove 52 and the port 66. With the valve body 86 in its upper position, as shown in the drawing, the annular groove 130 is in. communication with the pressurized air from passageway 76 through the annular groove and port 64there-by applying pressure to the head end of the piston 20 and to the rod end of the piston 22; note that as per the prior discussion of the annular groove 128, at' the same time,the rod nd of the piston 20 and the head end of the piston 22 are'connected to exhaust. With the valve body 86 in its lowermost position, the annular-groove 130 is no longer in communication with the source of air pressure through the passageway 76 and is 'moved in communication withthe annular groove 54 via the port 68 and thence to communicate with the atmosphere via the passageway 74 thereby connecting the head end of the piston 20 and the rod end of the piston 22 to exhaust; note thatas per the prior discussion of the groove 128, at the same time, the rod end of the piston 20 and the head end of the piston 22 are connected to the source or air pressuretherebyresulting in movement of the tandem piston assembly in "an upward position. The passageways 72 and 74 can be either connected separately to atmosphere or together through a common passage.

Note that by reciprocation of the body 86- between the two positions shown and described, the result will be pressurization first on one side of the tandem pistons 20 and 22 to cause movement in one direction and'then automatically to the other side to cause movement in an opposite direction. The two positions are definitely loeatedby means of the detent assembly 116. Thus, with the movable body 86 in its uppermost position, the detent assembly 116 will -.be in groove 112 and will maintain the movable body 86 in that position. With the body member 86 in its lowermost position, the detent assembly 116 will then be engaged in the annular groove 114 to thereby maintain the movable body 86 in that position. Movement between the two positions represented by the annular grooves 112'and 114 is caused by the contact of the piston heads 20 and 22 with the

pins

92 and 102, respectively. With the apparatus in the condition as shown in the drawing, pressurized air is communicated to the head end of the piston 20 and to the rod end of the piston 22 thereby causing movement of the tandem piston assembly in the downward direction. As the movement of the tandem piston assembly approaches its lowermost position, the bottom side of the piston 20 will engage the pin 92 moving it downwardly against the force of the spring 98; the body member 86, however, will not yet move. As the motion ofthe piston 20 continues downwardly, the force exerted upon the spring 98 increases until the pin 92 bottoms out in the cavity 88, at which time the locking force of the detent assembly 116 within the groove 112 is overcome, whereby the stored energy in the spring 98 causes the body 86 to move downwardly; the movement of the body member 86 will be terminated as the detent assembly 116 engages the second annular groove 114. This, then, changes, i.e., reverses, the pressure conditions of the

passageways

38 and 40 such that pressurized air is then applied to the rod end'of the piston 20 and to the head end of the piston 22 causing the tandem piston assembly to move upwardly. This motion will be continued until the piston 22 engages the pin 102 and the spring 108 is compressed; when pin 102 bottoms out in cavity the detent assembly 116 will be unseated from the groove 114 and the movable body 86 will then be moved upperwardly until the detent assembly 116 seats within the annular groove 112 and the cycle is ready to be repeated. Note that by using the springs 98 and 108,'a positive, snapping action in the'motion of the movable body 86 is assured, since the stored energy of the springs 98 and 108 as each is compressed, will assure that the valve body 86 will move to the next position. By this means thevalve' piston assembly is shown and described in the above-noted,

copending patent application. I I a The ball bearing and the spherical seat l 24 of the spring retainer 122 provide a relatively large bearing surface area such that the wear thereupon is minimized whereby the life of the ball 120 and of the sphericalseat portion 124 of the retainer 122 is enhanced. By providing the enlarged surfaces of contact between the ball 120, the spherical seat 124 and the grooves 112 and i14,"th'e bearing loads required for effective locking action by the spring 126 can be readily provided with minimum wear."

This is of importance since the movable body 86 will be S subjected to a substantial number of cycles and hence wear must be maintained at a minimum to provide adequate life. i a

A diametrical clearance is provided between the outer ends of. the body member 86 and the inside diameters of the caps v82 and 84 such that in its uppermost position, the port 70. will be communicated with the volume at that end ofthe body member 86 enclosed by the cap 84. Likewise, with the movable body 86 in its lowermostposition, the volume at the end-enclosed by. the cap 82 will be communicated to the port 58. This will prevent the airunder the caps 82 and84 frombeing trapped and pressurized; if.-air were permitted to be pressurized at theselocations the forces required to cause shifting of the body member 86 can vary under dii ferent conditions and hence upset the reciprocating action of movable member 86 and hence of tandem pistons 20 .and 22.

While it will be apparentthat the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed isi '1. A valve assembly adapted to be supported in a bore me housing member for communicating a first pair of passages to a second pair of passages comprising: a fixed body member fixedly mounted in the bore and having a through bore, said fixed :body member having a' plurality of annular grooves each in communication with a different one of the first and second pair of passages in the housing member and a plurality of passageways each communicating a different one of said first plurality" of annular grooves with said through bore, a movable body member reciprocably supported in said through bore for reciprocation between two positions, 'saidmovable body member having a pair ofaxially spaced communicating grooves in its outer surface, one of said communicating grooves connecting a first and second of said plurality of passageways together with said movable body member in oneof said positions and said first and a third of said plurality of passageways together with'said movable body member in the other of said positions, the other of said communicating grooves connecting'saidthird and a fourth of said plurality of passageways together with said movable body-member in said one of said positions and said second and fourth of said plurality of passageways together with said movable body member in said other of said positions, detent means for holding said movable body member in said one and said other of said positions, said detent means comprising a pair of axially spaced annular locking grooves located in said fixed body member and a detentassembly located in' a radial bore through said movable body memberland including a ball, a spring retainer and a spring in engagement with said spring retainer and engaging said ball for urging said ball and saidspring retainer apart, said retainer terminating in a nose portion having a contoiir of a portion of a sphere, said nose portion and said ball being engageable in one of said locking grooves with said mov-' able body member in said one of said positions and in the other of said locking grooves with said movable body member in said other of said positions', said movable body member having agvretainer cavity at each of its opposite ends for receivinganactuating assembly, each said actuating assembly; comprising a pin member'having a pin portion extending outwardly from-said retainer cavity with which it is associated,la spring member engaging said pin memberfor urging it outwardly, and a retainer'for-limiting the. outward movement ofsaid pin member, said spring member having a preselected compressive preload on said pinmember and having a preselected spring rate relative to the spring rate of said springofsaiddetent means whereby movement of said movable body member from said one positionto said otherposition and hence movement of said detent assembly from one of said retaining grooves to the other of saidretaining grooves will occur only after said pin member has been moved into said retainer cavity a preselected distance with the energy of said spring member causing indexing of said detent assembly to saidother of said retaining grooves after said detent assembly has moved from said one of said retaining grooves.

2. The valve assembly of claim 1 further including a pair of capmembers enclosing the oppositeends of the bore in the housing member with each having an aperture for receiving said pin member of said actuating assembly at that end, and means for communicating the volumes enclosed by said caps to low pressure.

3. For controlling the reciprocation of a piston in a cylinder, a valve assembly adapted to be supported in a bore in a housing member for communicating a first pair of passages connected to the cylinder at opposite ends of the piston to a second pair of passages with one connected to a pressure source and the other to a low pressure outlet, said valve assembly comprising: a fixed body member fixedly mounted in the bore and having a through bore, said fixed body member having a first and second annular groove each in communication with one of the first pair of passages and a third and fourth annular groove each in communication with one of the second pair of passages in the housing member, said first, second, third and fourth passages each in communication with said through bore, a movable body member reciprocably supported in said through bore for reciprocation between two positions, said movable body member having a pair of axially spaced communicating grooves in its outer surface, one of said communicating grooves connecting said first and third of said annular grooves together with said movable body member in one of said positions and said first and said fourth of said annular grooves together with said movable body member in the other of said positions, the other of said communicating grooves connecting said second and said fourth of said annular grooves together with said movable body member in said one of said positions and said second and third of said annular grooves together with said movable body member in said other of said positions, detent means for holding said movable body member in said one and said other of said positions, said detent means comprising a pair of axially spaced annular locking grooves located in said fixed body member and a detent assembly located in a radial bore through said movable body member and including a ball, a spring retainer and a spring in engagement with said spring retainer and engaging said ball for urging said ball and said spring retainer apart, said retainer terminating in'a nose portion having a contour of a portion of a sphere, said nose portion and said ball being engageable in one of said locking grooves with said movable body member in said one of said positions and in the other of said lock-- ing grooves with said movable body member in said other of said positions, said movable body member having a retainer cavity in one end for receiving an actuating assembly, said actuating assembly comprising a pin member having a pin portion extending outwardly from said retainer cavity with which it is associated and into the cylinder for engagement by the piston, a spring member engaging said pin member for urging it outwardly, and a retainer for limiting the outward movement of said pin member, said spring member having a preselected compressive preload on said pin member and having a preselected spring rate relative to the spring rate of said spring of said detent means whereby movement of said movable body member from said one position to said other position and hence movement of said detent assembly from one of said retaining grooves to the other of said retaining grooves will occur only after said pin member has been moved by the piston into said retainer cavity a preselected distance with the energy of said spring mem ber causing indexing of said detent assembly to said other of said retaining grooves after said detent assembly has moved from said one of said retaining grooves.

4. For controlling the reciprocation'of a piston in a cylinder, a valve assembly for communicating afirst pair of passages connected to the cylinder at opposite ends of the piston to a second pair of passages with one connected to a high pressure source and the other to a low pressure outlet, said valve assembly, comprising: a first body :member having abore and having ,a first passage-means for communicating with one of the first pair. of passages and said bore, second passage means for communicatingwith the other of the-first pair of passages and said bore, a third passage means for communicating withone of the second pair of passages. and said bore and a fourth passage means for communicating withthe other of the second pair of passages and said. bore, a movable body member reciprocably supported in said bore for reciprocation between two positions, said movable body member having a first and second communicating means, one of said communicating means connecting said first and third passage means together with said movable body member in one of said positions and said first and said fourth of said passage means together with said movable body member in the other of said positions, detent means for holding said movable body member in said one andsaid other of said positions, said detent means comprising a pair of axially spaced locking cavities, a detent assembly located in a different cavity and including a lock member and means for urging said lock member out of said different cavity, said lock member being engageable in one of said locking cavities with said movable body member in said one of said positions and in the other of said locking cavities with said movable body member in said other of said positions, sad movable body member having an actuating assembly means at one end for engaging the. piston whereby movement of said movable body member from said one position to said other position and hence movement of said detent assembly from one of said retaining cavities to the other of said retaining cavities will occur only after said actuating assembly means has been engaged by the piston.

5. The valve assembly of claim 4 with said actuating assembly means comprising means engageable by the piston and resiliently resisting movement by the piston and for storing energy responsively to movement by the piston for moving said movable body member from one of said retaining cavities to the other of said retaining cavities.

6. The valve assembly of claim 4 with said lock member being a ball and with said actuating assembly means being located in an opening in the end of said movable body member.

7. A valve assembly adapted to be reciprocated in a bore in a housing member for communicating a pair of inlet passages to three passages for high and low pressure with two being for one pressure and one for the other pressure, a fixed body member fixedly mounted in the bore and having a through bore, said fixed body member having a first and a second groove each in communication with a different one of the inlet passages in the housing member, a third groove in communication with the passage for the other pressure, and a fourth and a fifth groove each in communication with a different one of the passages for the one pressure, a movable body member reciprocably supported in said through bore for reciprocation between two positions, said movable body member having a pair of axially spaced communicating grooves in its outer surface, one of said communicating grooves communicating said first and third grooves together with said movable body member in one of said positions and said first and fourth grooves together with said movable body member in the other of said positions, the other of said communicating grooves communicating said second and fifth grooves together with said movable body member in said one of said positions and said second and third grooves together with said movable body member in said other of said positions,-detent means for holding said movable body member in said one'and said other of said positions, said detent means comprising a pair of axially. spaced annular locking vgrooveslocated in said fixed body member and a detent assembly located in a radial bore through said movable bodymember and including a ball,.a spring retainer anda spring in engage, ment with said spring retainer and .cngaginggsaid ball; for urging said vball :and said spring retainer apart; said retainer terminating'ina' nose portion .havinga contour. of a portion of a. sphere, said noseportion and said balL being engageable inone-of said locking grooves withsaid movable body member in said one of said positionsand in the other of saidt locking'grooves with said movable. body member in said other of 'said positions, said mov able body member having a retainer cavity-at each of its opposite ends for 'receivingan' actuating assembly, each said actuating assembly'comprising a pin member having a pin portion extending outwardly from said retainer cavity with which it is associated, a spring member engaging said pin member for urging it outwardly, and a retainer for limiting the outward movement of said pin member, said spring member having a preselected compressive preload on'said pin member and having a preselected spring rate relative to the=spring rate of said spring of said detent means whereby movement of said movable body member from'said' one position to said other position and hence movement'of said detent assembly' from one of said retaining grooves to the other of said retaining grooves will occur only after said pin member has been moved into said retainer cavity a preselected distance with the energy of said spring member causing indexing of said detent assembly to said other of said retaining grooves after said detent assembly has moved from said one of said retaining grooves. i

8, valve assembly for controlling the reciprocation of a pair of tandemly connected pistons each located in one of a pair of coaxially disposed cylinders in a housing member and adapted to be supported in a bore in a housing member with the bore interconnecting the cylin-' ders and for communicating a pair of inlet passages to threepassages for high and low pressures with two being for one pressure and one for the other pressure, a fixed body member fixedly mounted in the bore and having a through bore, said fixed body rnember having a first and a second groove each incommunication with a different one of the inlet passages in the housing member, a third groove in communication with the passages forthe other pressure and a fourth and a fifth groove eachin communication with a different one of they passages for the one, pressure, a movable body member reciprocablysupported in said through bore for reciprocation between two positions, said movable body member having a pair of axially spaced communicating grooves in its outer surface, one of said communicating grooves communicating said first and third grooves together with said movable body member in "one of saidpdsitions and said first and fourth grooves together with said movable body member in ,the. other of said positions, ,the other of said communicating grooves communicating said second and fifth grooves to-I g'ther with saidmovable body member-in said. one of said positions and said second and third grooves together. with said movable body-member; in said other of ,said positions, detent means for holding said movable body member in said one .and.said ,-0ther of: said positions lospring retainer and engaging said ballifor urging said ball and said spring retainer'ap-art, said retainer terminating in anose portionhaving a'contour of" a portion 'of a sphere, said nose portionand said ballbeing'engageable in one of said locking'grooves with said movable body member in said one of said positions and in the other of said locking grooves w'ithsaid movablebody member in said other of said positions, said movable body member having a retainer cavity at each of its opposite ends for receiving an actuating assembly, each said actuating assembly comprising a pin member having a pin portion extending outwardly from said retainer cavity with which it is associated and into that one of the cylinders at that end, a spring member engaging said pin member for urging it outwardly, and a retainer for limiting the outward movement of said pin member, said spring member having a preselected compressive preload on said pin member and having a preselected spring rate relative to the spring rate of said spring of said detent means whereby movement of said movable body member from said one position to said other position and hence movement of said detent assembly from one of said retaining grooves to the other of said retaining grooves will occur only after said pin member has been moved by that one of the pistons with which it is associated into said retainer cavity a preselected distance with the energy of said spring member causing indexing of said detent assembly to said other of said retaining grooves after said detent assembly has moved from said one of said retaining grooves.

9. A valve assembly for controlling the reciprocation of a pair of tandemly connected pistons each located in one of a pair of coaxially disposed cylinders in a housing member and adapted to communicate a first pair of passages connected to the cylinders at opposite ends of the pistons to a second pair of passages with one connected to a high pressure source and the other to a low pressure outlet, said valve assembly comprising: a first body member having a bore and having a first passage means for communicating with one of the first pair of passages and said bore, second passage means for communicating with the other of the first pair of passages and said bore, a third passage means for communicating with one of the second pair of passages and said bore and a fourth passage means for communicating with the other of the second pair of passages and said bore, a movable body member reciprocably supported in said bore for reciprocation between two positions, said movable body member having a first and second communicating means, one of said communicating means connecting said first and third passage means together with said movable body member in one of said positions and said first and said fourth of said passage means together with said movable body member in the other of said positions, the other of said communicating means connecting said second and said fourth of said passage means together with said movable body member in said one of said positions and said second and third of said passage means together with said movable body member in said other of said positions, detent means for holding said movable body member in said one and said other of said positions, said detent means comprising a pair of axially spaced cavities, a detent assembly located in a different cavity and including a lock member and means for urging said lock member out of said ditferent cavity, said lock member being engageable in one of said locking cavities with said movable body member in said one of said positions and in the other of said locking cavities with said movable body member in said other of said positions, said movable body member having an actuating assembly means at each end for engaging that one of the pistons at that end whereby movement of said movable body member from said one position to said other position and hence movement of said detent assembly from one of said retaining cavities to the other of said retaining cavities will occur only after said actuating assembly means has been engaged by the piston with which it is associated.

10. The valve assembly of claim 9 with said actuating assembly means comprising means engageable by the piston with which it is associated and resiliently resisting movement by the piston with which it is associated and for storing energy responsively to movement by the piston with which it is associated for moving said movable body member from one of said retaining cavities to the other of said retaining cavities.

11. The valve assembly of claim 10 with said lock member being .a ball and with each said actuating assembly means being located in one of a pair of openings at opposite ends of said movable body member.

12. A valve assembly comprising a fixed body member, a movable body member, detent means for holding said movable body member in one of a plurality of positions, said detent means comprising a locking cavity at each of said positions and a detent assembly located in a different cavity and including a ball, an elongated spring retainer, and a bias spring in engagement with said spring retainer and said ball for urging said ball and said spring retainer apart, said retainer terminating in a nose portion having a contour of a portion of a sphere, said nose portion and said ball being engageable in said locking cavity for locking said movable body member in the corresponding one of said positions, said movable body member having actuating assembly means for moving said movable body member to said each of said positions and including resisting means for resiliently resisting movement of said movable body member and for storing energy responsively :to forces applied thereto for moving said movable body member and for releasing said energy for causing move ment of said movable body member to a next one of said positions when the magnitude of said forces overcomes the locking eifect of said lock member.

13. The assembly of claim 12 in which said resilient means includes a spring and said resisting means includes a spring member with the spring rates of said spring and said spring member selected such that the locking effect of said lock member will be overcome at a preselected force having a magnitude suflicient to impart sufficient stored energy to said spring member whereby movement of said movable body member from one position to another will be effected.

14. In a valve assembly the improvement comprising: a fixed body member, a movable body member, detent means for holding said movable body member in one of a plurality of positions, said detent means comprising a locking cavity at each of said positions and a detent assembly located in a different cavity and including a ball, an elongated spring retainer, and a bias spring in engagement with said spring retainer and said ball for urging said ball and said spring retainer apart, said retainer terminating in a nose portion having a contour of a portion of a. sphere, said nose portion and said ball being engageable in said locking cavity for locking said movable body member in the corresponding one of said positions, said movable body member having actuating assembly means for moving said movable body member to said each of said positions.

References Cited UNITED STATES PATENTS 1,839,540 1/1932 Farr 91329 2,555,018 5/1951 Von Seggern 91-329 3,261,265 7/ 1966 Weik 91-329 3,276,381 10/1966 Harklau 91-3 29 1,861,442 6/ 1932 Hammerstein 251-297 FOREIGN PATENTS 325,269 9/ 1920 Germany.

PAUL E. MASLOUSKY, Primary Examiner.