US3187637A

US3187637A - Multi-position cylinder apparatus and control therefor

Info

Publication number: US3187637A
Application number: US200167A
Authority: US
Inventors: John R Edmund
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1962-06-05
Filing date: 1962-06-05
Publication date: 1965-06-08
Anticipated expiration: 1982-06-08

Description

June 8, 1965 J. R. EDMUND 3,187,637

MULTI-POSITION CYLINDER APPARATUS AND CONTROL THEREFOR Filed June 5, 1962 2 Sheets-Sheet 1 POSiTiON 73 e|- 69 SOLENOiD III 7 l El 63; P 2 El 64 I 3 I 4 g: I l3 l8 N 3 7l|46 8 El I09 H E=ENERGiZED El n7 5 f INVENTOR. JOHN R. EDMUND United States Patent() 3,187,637 MULTl-POSXTION CYLHNDER APPARATUS AND CGNTROL THEREFQR John R. Edmund, Berkeley, Calif ass'ignor to Westinghouse Air Brake Company, Wilmerding, Pa, a corporation of Pennsylvania Filed June 5, 1%2, Ser. No. 260,167. 6 Claims. (Cl. 91-467 This invention relates to a multi-position cylinder apparatus and controls therefor and more particularly to such an apparatus utilizing a plurality of fluid pressure operated pistons and cylinders forming a cylinder train operable to a plurality of selected positions for any desired function or purpose. p

industrial requirements for mold-positioning apparatus are many and varied, with different types of equipment utilized to solve diflferent necessities.

According to the present invention, there is provided a1 new and novel mold-positioning apparatuscomprising a plurality of pistons and cylinders compounded into a cylinder train such that the total displacement of the train is a function of position of each piston and cylinder unit of the train. The positioning of each piston and cylinder unit is, controlled by a solenoid operated control or pilot valve for selectively supplying or venting fiuidu nder pres- Sure thereto or from in a prescribed sequence as required by the selected position desire-d.

. In the accompanying drawings:

FIG. 1 is a diagrammatic, view of a multiple position cylinder train apparatus and the controls therefor including a plurality of control or pilot valves operable selectively into either one of two positions responsively to selective energization of two separate solenoids.

FIG. 2 is a sequence table indicating the sequence of ,energization of the different solenoid pilot valves to cause the apparatus ot FIG. 1 to be placed in any one of eight different positions.

FIG. 3 is a diagrammatic viewyof the same multiple position cylinder train apparatus as shown in FIG. 1 with Description Referring to FIG. 1 the multiple-position cylinder train includes three

cylinders

1, 2 and 3 each having a bore 4,

d, and 6, respectively, in which

respective pistons

7, 8 and 9 are slidably positioned. The bores 4;, 5 and 6 are of the same diameter in consequence of which the

pistons

7, 3 and 9 are of the same effective area. Piston '7 in bore 4 forms two chambers it and 11 respectively with the end cap 12- and face plate between bores 4- and 5. Piston 8 forms a chamber 14 in bore 5 respectively with the face plate 13 and a chamber 15 with the endcap l6.

Piston 9 forms two

chambers

17 and 18 in bore o respectively with the end cap 19 and thebottom of cylinder 3.

The respective end caps of each cylinder are secured thereto by suitable means such as bolts 29. The two

cylinders

1 and 2 are secured together by bolts 20 also, with the face plate 13 separating the chambers 11 and 14. The piston 7 has a stem 21 extending through a leak-proof port 22 in the end cap 12 to a stationary mounting bracket 23 at which point said stem is pivotally secured by a pivot pin 24. Piston S and piston 9 are connected to opposite ice a guide groove a of a supporting member suitably mounted by means not shown about the positioning guide pin 29. as shown in FIG. 5.

the eight numbered positions is exactly equal and designated hereinafter for illustrative purposes as one unit (114,). This distance of one unit (la) is exactly equal to the traveled distance or stroke of piston 9 in the bore 6 of cylinder 3, thereby movement of the cylinder 3 relative to the piston 9 will cause movement of the guide pin 29 exactly one unit in a direction dependent upon the movement of the cylinder 3. The travel distance or stroke of piston 8 in the bore 5 of cylinder 2 is made exactly equal to two of said units (211) such that full movement of piston 3 in either directionwill cause movement of the guide pin 29 two units in either direction. Travel distance of the cylinder 1 relative to the piston 7- is exactly equal to tour of aforesaid units (4a), thereby complete travel of the cylinder 1 about the piston 7 in the bore 4 will effect movement of the guide pin 29 four units in either. direction dependent on the direction of the movement of the cylinder 3. It can thus be seen that combinations of diilerent movements ofthe cylinder 3 relative to the piston- 7, the piston 8 in the bore 5 of cylinder 2, and the cylinder 3 relative to the piston 9, can produce a plurality of combinations of additive and subtractive unit measures to thereby provide a plurality of positions for the guide'pin 29 in the guide slot 3 under the control of the fluid pres sure supplied to the different chambers of said cylinders as explained hereinafter.

. Fluid under pressure is supplied to each of the

cylinders

1, 2 and 3 from a snitablesource represented herein by a reservoir 31 which is connected to each of the chambers of each cylinder by various pipes and under the control of various pilot valves explained hereinafter.

Control of fluid under pressure to or from the charmbers 10 and 11 of cylinder 1 is effected by thesolenoid operated pilot valve 32.

Control of fluid under pressure to or from the

chambers

14 and 15 of cylinder 2 is effected by the solenoid operated pilot valve 33.

Control of fluid under pressure to or from the

chambers

17 and 18, of cylinder 3 is effected by the solenoid operated pilot valve 34.

Each of the

pilot valves

32, 33 and 34 is operable responsively to 1 energization of two separate solenoids. Solenoids S1 and S2 control spool valves (not shown) to establish internal passages such that when solenoid S1 is energized, fluid flow within said pilot valve is in a manner and direction indicated by solid arrows on the drawing, and when solenoid S2 is energized, the fluid flow within said pilot valve is in a manner and direction indicated by dotted arrows. In an exactly similar manner, solenoids S3 and S4 control similar spool valves (not shown) to establish internal passages of pilot valve 33, and'solenoids S5 and S6 control spool valves (not shown) to establish similar passages within pilot valve 34.

Associated with pilot valve 32 in controlling flow of fluid under pressure to and from the cylinder 1 is a pair of quick release valves 35 and 36 of the well-known type, a pair of

check valves

37 and 38 and a pair of

variable chokes

39 and 40. The quick release valves 35, 36 41, 42, 47 and 43 may be of the well-known type shown in US. Patent 1,506,012 of L. V. Lewis, issued August 26,

-' It should be noted that the distance between eachof aromas? 1924, to which reference may be had for a detailed description. Briefly, however, this type of-quick release valve employs a floating flexible diaphragm which is flexedor biased in onedirection by supply of fluid under pressure from a supply communication to one side of said diaphragm to thereby connect the supply communication to a delivery communication while closing an exhaust communication. Upon'reduction of the pressure in the supply communication below that in the delivery communication, the diaphragm will be flexed or-biased in an opposite direction to connect the delivery communication to the exhaust communication while closing 05 the supply (i. S5 and thence to groundat wire 79, thereby energizing the three solenoids S1, S3 and S5. 7

With solenoid Si energized, the flow of fluid under pressure from the reservoir 31, supply pipe 8d and branch pipefil is directed through the pilot valve 32 in a manner indicated by the solid arrows on pilot valve 32 such that iluid under pressure is supplied into pipe 53, through the check valve 37 to -pipe 82 to condition the quick release valve 35 in the usual manner to permit flow of fluid under communication to effect a rapid venting-or so-called" quick release of fluid pressure from the delivery communication and any device connected thereto. The

check valves

37, 38, 43, d4, 49 and 56 provide unrestricted oneway flow of fluid under pressure in the supply communication toward the corresponding quick release valvevand the

chokes

39, 40, 45, 46, 51 and 52 restrict reverse flow in the supply communication away from the corresponding quick release valve to trigger the operation of the quick release valve to etiectthe rapid venting locally at the exhaust communication thereof. It will be understood uniform, that is the rate of venting'thereof is uniform, once they are triggered and that the variable chokes cause variation in the time interval elapsing between the instant the corresponding solenoid-operated pilot valve is energized to .vent the supply communication and the instant that the speed of operation of the quick release valves is similar pair of

quick release valves

41 and 42, a pair of i "

check valves

43 and 44, and a pair of variablech-

okes

45 and 46. i

Pilot valve 34-1il ewise operates in conjunction with a pair of similar

quick release valves

47 and 48, a pair of check valves 4% and 5t and apair of variable chokes 51 and 525,; each operationally explained hereinafter.

Aplurality of pipes53, 54,55, 56, 57 and 58 interconnect the various check valves with output passages and exhaust passages of the respective pilot valves as described hereinafter. I

Energization of the different solenoids can be accomplished by circuitry including a source of supply, such as abattery 59 and supply wire 69 and any type of switch or contacts controlled by any suitable means as manually or by tapes, but for purposes of illustration are shown herein as simple manually operated

push button switches

61, 62, 63, 64, 65, 6'7 and 68 which when closed enable completion of various circuits explained hereinafter and when opened by spring means (not shown) upon release of each button, render the circuitry incomplete. Hereinafter, when referring to the closing of any one of the switches till through 68, it must be understood that all the others are -open and that only one switch is to be closed at any one time. 7

Operation-FIG. 1

In operation, the train of the

cylinders

1, 2 and 3 is positioned in one of eight different positions as explained sequentially hereinafter. Referring to the table of FIG. 2,

to position the apparatus in Position 1 (the leftmost position of FIG. 1), the solenoids S1, S3 and S5 must be energized by closing push button switch 61 (PEG. 1).

With switch 61 closed three parallel circuits are com- ,pleted from the battery 59 and supply wire as through the switch 61 to wire 69 and thence: (a) to rectifier 7 6, Wire pressure through the quick release valve 35 as indicated by the solid arrow to a flexible pipe ild to the chamber iii of cylinder 1 at'the port 845. Also, while solenoid S1 is energized, the pipe 54% is vented toatmosphere at port thereby bleeding down the pipe tl through the choke dil and pipe 54 to cause operation'ot the quick release valve 36 in a normal manner to vent chamber 31 of cylinder 1 by way of port 3'7, flexible pipe 88 to atmosphere at the vent pipe 8? ofthe quick release valve 36' as indicated by v the dotted arrow thereon. With chamber iii supplied with iiuid under pressure and chamber ll vented as described, the cylinder 1 will be positioned in its left-most position as indicated on'the drawing. I

Simultaneously with the left-'rriostpositioning of cylinder 1 as justdescribed, the energization of solenoid S3 effects a flow of fluid under pressure from the reservoir 31, supply pipe 8i? and branch pipe 96 through the pilot valve 33 ina mannerindicated by the solid arrows as pilot valve 33 such that fluid under pressure is supplied into pipe 56, through the check valve 44 to pipe M,

ber 14; of cylinder 2 by Way of port 97, flexible pipe 98 to atmosphere at the vent pipe 99. of the quick release valve 41 as indicated by the dotted arrow thereon. With chamber 15 supplied with fluid under pressure and cham ber 14 vented to atmosphere as just described, the piston 3 in cylinder 2 will be positioned 'in its left-most position.

Simultaneously, with the positioning of cylinder 1 and piston 8 effected by the energization'of solenoid S1 and S3, the energization of solenoid S5 effects a flow of fluid under pressure from the reservoir 31, supply pipe 8% through the pilot valve '34 in a manner indicated by the solid arrows on pilot valve 34 such that the fiuid under pressure is supplied into pipe 57, through the check valve 49 to pipe 180, through the quick release valve 47 which operates in a normal manner responsively to the fluid under pressure in pipe 100 .to close the vent port 1011 thereof and permit flow of fluid under pressure therethrou'gh as indicated by thersolid arrow to a flexible pipe 1% and thence to chamber 17 of cylinder 3 at the port ltlil. Also, while solenoid S5 is energized, the pipe.

5d is vented'to atmosphere at port 104 as indicated by the solid arrow on the pilot valve 34, thereby bleeding down the pipe through the variable choke 52 and pipe 53 to cause operation of the quick release valve 48 in a normal manner to vent chamber 18 of cylinder 3 by way of port 106, flexible pipe 167 to atmosphere at the vent pipe N8 of the quick release valve 43 as indicated by the dotted arrow thereon. With chamber 17 of cylinder 3 supplied with fluid under pressure and chamber 18 vented as described, the cylinder 3 will be positioned in its left-most position asindicated on the drawing.

With the cylinders supplied with fluid under pressure as just described, the guide pin 29 will be positioned in the guide slot fit) at Position 1 as desired, It can thus be seen that it is. the additive effect of the supply and venting of fluid under pressure to or from chambers and ll of cylinder 1 to position cylinder 1 and simultaneously cylinder 2, plus the supply and venting of fluid under pressure to the cylinder 2 to position the 'piston 8, plus the supply or venting of fluid under pressure to or from

chambers

17 and 18 of cylinder 3 to position the cylinder 3, that results in the desired positioning of the guide pin 29'. V

From the above discussion it can be seen that with the solenoids S1, S3 andSS energized, the

respective pilot valves

32, 33 and 34 are positioned such that fluid under-pressure is supplied to the chambers of cylinders 1, 2Iand 3 to position the guide lug 29 in its left-most position indicated as Position 1 and to be taken hereinafter as the initial position.

FIG. 1-P0sition 8 In view of the described positioning of the cylinders 1, Zand 3 with solenoids S1, S3 and S5- energized, it can be assumed that the effect of deenergizing the aforesaid solenoids and energizing the opposing solenoids S2, S4 andiso would be to reposition the cylinders to their respective right-most positions to cause positioning of the guide pin 29 in the extreme right position indicated as Position 8. 7

According to the chart of FIG; 2, with solenoids S1, S3 andSS deenergized and solenoids S2, S4, and S6 energized, the cylinder train should be positioned in Position 8. To energize solenoids S2, S4 and S6, it can be seen from FIG. 1 that push-button switch 68 should be closed to complete a circuit from the battery 59 and supspool valves (not shown) of each of the pilot valves 32,

33 and 34 such that internal passages (not shown) will be positioned such that the flow of'fluid therethrough is that indicated by the dotted arrows. With the solenoid S2 energized, the flow of fluid under pressure from the reservoir 31, supply pipe 89 and branch pipe 81 is directed through the pilot valve 32 in a manner that the fluid under pressure is supplied into pipe 54 through the check valve 38 to pipe 86 where the pressure acting on the quick release valve 36 will condition the quick release valve such that the vent port 89 willbe blocked ofl and fluid under pressure may flow through said quick release valve 36 as indicated by the solid arrow to the flexible.

pipe 88 and thence to the chamber 11 of cylinder 1 by way of port 87. Also, while solenoid S2 is energized, the pipe 53 is vented to atmosphere at port 85 in the i d tioned'by deene'rgization of the solenoid S3 and energiza tion of solenoid S4. With the spool valves (not shown) of pilot valve 33 so positioned, fluid under pressure is supplied into pipe 55, through the check valve 43 to pipe 96, where the pressure therein conditions the quick release valve 41 such that the vent port 99 is closed off and a passage is open tov permit flow of fluid under pressure through said check valve. 41 to the flexible pipe 98 and port 97 into chamber 14 of cylinder 2. Also, while solenoid S4 is energized, the pipe 56 is vented to atmosphere at the port 95 inthe pilot valve 33 as indicated by the dotted arrow, thereby bleeding down the pipe 91 through the variable choke 46. and pipe. 56 to cause operation of the quick release valve 42in a normal manner to vent chamber 15 of cylinder 2 by way of port 94, flexible pipe 93 to atmosphere at the vent pipe 1 92 of the quick release valve 42 as indicated by the dotted arrow thereon. With chamber 14 suppliedwith fluid under pressure and chamber 15 vented as just described,

the piston S and connected'piston stem will be positioned in its right-most'position with the piston 8 against pilot valve 82 as indicated by the dotted arrow thereby bleeding down the pipe 82 through the variable choke 39 and pipe 53 to cause operation of the quick release valve in a normal manner to vent chamber 10 of cylinder 1 by way of port 84, flexible pipe 83 to atmosphere at the vent pipe 120 of the quick release valve 35 as indicated by the dotted arrow thereon. With chamber 11 supplied with fluid under pressure and chamber ,10 vented as just described, the cylinder 1 will be positioned in its right-most position four units from the initial positioning with the end cap 12adjaccnt the piston 7.

Simultaneously, with the positioning of cylinder 1 in its right-most position, energization of the solenoid S4 effects a flow of fluid under pressure from the reservoir 31 and supply pipe and branch pipe through internal passages (not shown) in the pilot valve 33 in a manner 3 and piston 9 an equal distance to the right of two units. Simultaneously, with the positioning of the cylinder 1 in its right-most position and positioning of the piston 8 in its right-most position, energization of solenoid S6 eflects positioningof spool valves (not shown) within pilot valve 34 such that fluid flow therethrough is directed in a manner indicated by the dotted arrow shown thereon. 'With energization of solenoid Sti'therefore, flow of fluid from the reservoir 31, supply pipe 80 is directed through the pilot valve 34 to pipe 58, through the check valve 50, to pipe where the fluid under pressure therein effects operation of the quick release valve 43 in a normal manner to cut ofl venting at the vent port 108 and permit flow of fluid under pressure therethrough into chamber 18 of cylinder 3 by way of flexible pipe 107 and port 196; Also, while solenoid S6is energized,

the pipe 57 is vented to atmosphere at port 104 in the pilot valve 34 to cause bleed down of pipe 101 through variable choke 51 and pipe 5'7 to effect operation of quick release valve 47 in a normal manner to vent chamber 17 of cylinder 3 by way of port 103, flexible pipe 102 and vent port 101 of the quick release valve 47 as indicated by the dotted arrow thereon. With chamber 17 vented and chamber 18 supplied with fluid under pressure as just described, cylinder 3 will be positioned to the right one unit to its right-most position with the piston 9 adjacent the end cap 19 thereof. It can thus be seen that due to the energization of the solenoids S2, S4 and S6, simultaneously,

cylinders

1 and 2 are positioned in their righhmost position as just described, piston 8 and connected piston stem 25 and cylinder 3 will also be positionedto the right-most position with cylinder 3 operating individually to its right-most position, thereby giving a total additive positioning to the right of seven units to cause the guide pin 29 to be positioned in the right-most position seven units from Position 1, a position indicated as Position 8 on the drawing.

Having now described how energization of the solenoid S1 of pilot valve 32, solenoid S3 of pilot valve 33, and the solenoid S5 of pilot valve 34 operates the respective pilot valves to control the fluid pressure supply and venting from the

cylinders

1, 2 and 3 to position the cylinder train in its extreme left-most position; and how energization of solenoid S2 of pilot valve 32, solenoid S4 of pilot valve 33, solenoid S6 of pilot valve 34, reverses the positions of the internal passages (not shown) of the respective pilot valves such that the control of fluid under pressure to and venting from the

cylinders

1, 2 and 3 is effected to position the cylinder train in its extreme right hand or Position 8; it can be seen that variations of energization of either one of the solenoids controlling each of the three pilot valves 32, 33and 34 may produce control operations to the various cylinders ares,

. '5; 1, 2 and 3 such as to position thecylinder train and consequently the guide pin 29 inany one of several intermediate positions in a manner explained hereinafter.

FIG. l-Josition 2 v t To position the cylinder train in Position 2 as indicated by'movement of the guide pin 29 in FIG. 1, it can be seen from the chart in FIG. 2 that solenoid S1, S3 and S6 must be energized. To energize this combination of solenoids, it is necessary to close the push button switch 62 of FIG. 1 thereby completing circuitry from the battery supply 59 and supplywire as through the switch 62 to a Wire 1121 and thence to three parallel circuits described as follows? (a) to rectifier 122, wire 71, the

- winding of solenoid S1 and thence to ground at wire tion of the three solenoids S1, S3 and S6.-

' With solenoid S1 energized, as' previously described, chamber 10 of cylinder 1 is supplied with fluid under pressure and chamber 11 is vented thereby positioning the cylinder 1 in itsleft-most position. With solenoid S3 energized, as previously described, chamber 15 of cylinder 2 is supplied with fluid under pressure and chamber 14 thereof is vented to atmosphere, thereby positioning the piston 8 and stem 25 therein in its leftmost position. With solenoid ss energized, as previously described, chamber 17 of cylinder Bis vented and chamber 18 thereof is supplied with .iluid under pressure, thereby causing the cylinder 3 and consequently .the guide pin 29 to be positioned to the right one unit a distance equal to the distance from Position 1 to Position 2 thereby positioning the cylinder train in Position 2.

FIG. 1- Psz'zi0n 3 7 As seen from the chart on FIG. 2, to' position the cylinder train in Position 3, solenoids S1, S4 and S must be energized. To energize this combination ofisolenoids, it is necessary to close the switch 63 of FIG. 1

to thereby establish a circuit from the battery supply 59 and supply wire fill through the switch 63 to a wire 12s and thence to three parallel circuits as follows: (a) to rectifier 127, wire '71 and the winding of solenoid S1 and thence to ground at wire'72; (b) wire 12%, rectifier 129, wire 115, the Winding of solenoid S4 and thence to ground at wire 116; (c) wire 128, rectifier 13% wire '73, the winding of solenoid S5 and thence to ground at Wire 79, thereby energizing solenoids S1, S4 and S5.

With solenoid S1 energized as previously described, the pilot valve 31?, controls fluid pressure supply and venting to cylinder 1 such that chamber 11 thereof is supplied with fluid under pressure, and chamber 11 is vented to atmosphere, thereby positioning the cylinder 1 in its left-most position. With solenoid S4 energized as previously described, the spool valves (not shown) of pilot valve 33 are positioned'to control the sup-ply and venting of fluid under pressure to cylinder 2 in a manner'to vent fluid under pressure from chamber 15 thereof, and supply fluid under pressure to chamber l lthereof to position the piston it in its right-most position within cylinder 2 and consequently position the cylinder 3 and guide pin 29 to the right a distance equal to the piston travel of piston 8. Energization of solenoid S5 as previously described eilects operation of the pilot valve to control supply of fluid under pressure to the cylinder 3 in a manner to supply fluid under pressure to the chamber 17 and vent the fluid under pressure in chamber 15 thereof to move the cylinder 3 in a left-hand direction with the bottom of the cylinder engaging the piston 9. Thus, the entire cylinder train has been positioned two units to the right the distance traveled by the piston 80f cylinder '2 a distance equal to the movement or" the guide pin 29 from' the initial Position lin the guide slot fill to Position 3 as desired.

' Fro. 1-Rosition 4 As seen. from the chart in FIG. 2 to position the cylinder train in Position 4; solenoids S1, S4 and S6 must be energized. To energize this combination of solenoids, it is necessary to close the switch 64 of FIG. 1 to thereby establish a circuitfror'n the battery supply 59 and supply Wire dd through the switch d'to a wire 131 and thence to three parallel circuits as follows: (a) to rectifier 132, wire 71, the winding of solenoid S1 and thence to ground at 72; (b) wire 133, rectifier 134}, who 115, the winding of solenoid S l and thence to ground at wire 11%; (0) wire 133, rectifier 135, wire 118, the Winding of solenoid S6 and thence to ground at 19, thereby energizing the solenoids Si, S4 and S6.

A-s previously described with solenoid S1 energized, the pilot valve 32 operates to 'supply iluid under pressure to chamber it). of cylinder 1 and vent chamber 11 thereof, thereby positioning cylinder 1 in its left-most position. Also as previously described, with the solenoid S4- energized, the spool valves, (not shown) of pilot valve 33 are positioned to effect the supply of iluid under pressure to chamber 1 of cylinder 2 and vent chamber 15 thereof to thereby position the piston 8 in its right-most position within cylinder 2 and consequently position the cylinder 5 and guide pin 29 to the right'two units, a distance equal to the piston travel of piston 8. Energization of solenoid S6 as previously described effects operation of pilot valve 34 to control a supply of fluid under pressure to the chamber 18 and vent fluid under pressure in chamber 17 of cylinder 3 to thereby position cylinder 3 an additional distance of one unit in the right-hand direction until the end cap 19 is adjacent to piston 9. Thus, the entire cylinder train'has been moved from the initial Position 1 the distance traveled by the piston 8 within the cylinder 2 plus the distance traveled by the cylinder 3 as piston 9 moves into engagement with the end cap 19, thereby giving a total displacement of three units to position the guide pin 29 three units from Position 1 to Position 4 as desired.

FIG. 1P0siti0ni 5 As seen from the chart in FIG. 2, to position the cylinder train in the Position 5, solenoids S2, S3 and S5 are energized. To energize this combination of solenoids, it is necessary to close the switch of FIG. 1 to thereby establish a circuit from the battery supply 59, supply Wire so through the switch d5 to a wire 136 and thence to three parallel circuits as follows: (a) to rectifier 137, wire 111,

' solenoid S3 and thence to ground at wire 76; (c) wire 138,

rectifier 14%, and wire 78 to the Winding of solenoid S5 and thence to ground at wire '79, thereby energizing the solenoids S2, S3 and S5.

As previously described, with the solenoid S2 energized, the pilot valve 32 operates to supply fluid under pressure to the chamber 11 of cylinder 1 and also vents chamber 11? thereof, thereby moving the cylinder 1 to the right four units to its right-most position with the piston 7 adjacent the end cap 12. Also, as previously described, with the solenoid S3 energized, pilot valve 33 is positioned to efiect the supply of fluid under pressure to chamber 15 of cylinder 2 and also vent chamber 14 thereof to thereby position the piston it in its left-most position within cylinder 2 with the piston 8 adjacent the face plate 13, consequently position the cylinder 3 and guide pin 29 to the left a distance equal to the piston travel of piston 8. Simultaneously, energization of solenoid S5 as previously described effects operation of pilot valve 34 to control the supply of fluid under pressure to the chamber 17 and vent fluid under pressure from chamber 18 of cylinder 3 to thereby position cylinder 3 to the right with the piston 19 adjacent the end cap 15. Thus, the entire cylinder train has been positioned to the right of the initial Position 1 the i distance traveled by the cylinder 1 moving relative to the piston 7 Within cylinder 1, therebygiving a total displacement as mentioned herein-before four so-called units to position the guide pin 29 four units from Position 1 to Position 5 as desired.

FIG. I-Paiition 6 As seen from the chart in FIG. 2, to position the cylinder train in Position 6, solenoids S2, S3 and S6 must be energized. To energize this combination of solenoids, it

is necessary to close the switch 66 of FIG. 1 to thereby lit) fiuid under pressure in chamber 18 thereof to thereby position cylinder 3 a distance in the left-hand position until the bottom of'cylinder 37 is adjacent thepiston 9. Thus, the entire cylinder train has been moved the distance traveled by the cylinder 1 relative to the piston 7 within the cylinder 1, plus t e distance traveled by the pis'ton 8 Within the cylinder 2 thereby giving a total displacement of six units to position the guide pin 29 six units from Position 1 to Position 7 as desired.

Prior to any of the above positioning operations, each of themovement operations of the three cylinders may be timed by use of the variable chokes associated with each of the chambers of said cylinders in arnanner now explained. Movement of piston 7 in the bore 4 within the winding of solenoid S3 and thence to ground atwire r 76; (c) wire 143, rectifier 145, Wire 11%, the winding of solenoid S6 and-thence to ground at wire 11?, thereby energizing the solenoids S2, S3 and S6.

As previously described, with solenoid S2 energized, the pilot valve 32 operates to supply fluid underpressure to chamber 11 of, cylinder 1 and vent chamber 16 thereof,

1 thereby positioning cylinder 1 in its right-most position with the piston. 7, thereof adjacent the end cap 12. Also, as previously described, with the solenoid SSenergized,

the spool' valves (not shown) of pilot valve 33 are positioned to etlfect the supply of fluid under pressure to charm? be 15 of cylinder 2 and vent chamber 14 thereof to thereby position piston 8 in its left-most posltionwithin cylinder 2. Energization of solenoid S6 as previously describedeflects operation of pilot valve 34 tdcontrol a supply of fluid under pressure to the chamber 18 of cylinder 3 and vent fluid under pressure in chamber 17 thereof to thereby position cylinder 3 in the right-hand direction 1 1 until the end cap 9 is adjacent thepiston 9. Thus, the

entire cylinder train hasbeenpositioned by the distance traveled'by the cylinder 1 about piston 7, plus the distance a the cylinder 3 moved about the piston 9, into engagement with the end cap 19 thereby giving a'total displacement of, as mentioned before, five so-called units to position the guide pin '29 five units from the Position 1 to Position 6 as desired. c c

As seen from the chart in FIG. 2, to position the cylinder train in the Position 7, solenoids S2, S4 and S must be energized. To energize this combination of'solenoids,

wire 1-15, the winding of solenoid S4 and thence to ground at Wire 1 16; (c) wire 14 8, rectifier 150, Wire 78,

cylinder 1 can be accomplished only by supply of pressure to one of the chambers 10 or 11 on either side of said piston 7 and venting of fluid pressure from the other side. it is a simultaneous supply of fluid under pressure to one of said chambers and venting of the other of said chambers which permits'movement of said piston. Therefore, regulation of e-ither the supply of fluid under pressure thereto or regulation of the venting of fluid under pressure from oneof the chambers will causeregula tion of the timing of the movement of said piston 7 or in actuality movement of cylinder 1 relative to said pi-stion 7. Associated with-each of said chambers is a variable choke for controlling the venting ofthe men- '45 and 46 control the venting of chambers 14 and-15,

respectively, of cylinder 2, and variable chokes 51 and SZ control the venting of the chambers 1-7 and 18, respectively', of the cylinder 3. Bycontrollingthe instant that venting of these chambers is' initiated by the quick release valves, each of the cylinders can be timed so that each individual cylinder wil-lcomplete its stroke in either direction in the same timethat any other given cylinder completes its stroke, therefore, the time to move the guide pin 2 9'from any given position to any other given position will'be constant and equal to the time required for any individual cylinder to be repositioned because the motion of the cylinder train is additive. Conversely, the

the Winding of solenoid S5 and thence to ground at wire 79, thereby energizing the solenoids S2, S4 and S5.

As previously described, with solenoid S2 energized,

the pilot valve 32 operates to supply fluid under pressure to the chamber 11 of cylinder 1 and vent chamber 10 thereof, thereby positioning the cylinder 1 in its rightmost position with the piston 7 adjacent the end cap 12. Also, as previously described, with the solenoid S4 energized, the spool valves (not shown) of pilot valve 33 are positioned to effect the supply of fluid under pressure to chamber 14 of cylinder 2 and vent chamber 15 thereof to thereby position the piston 8 in its right-most position within cylinder 2 adjacent the end cap 16 and consequently position the cylinder 3 and guide pin 29 to the right a distance equal to the piston travel of piston 8. Energization of solenoid S5 as previously described etfects operation of pilot valve 34 to control the supply of fluid under pressure to the chamber 17 of cylinder 3 and vent speed of motion between any two positions will be proportional to distance between the two positions, thus the cylinder train is capable of moving at a speed equal to the sum of the speed of movement of the individual cylinders of the train. While the system described hereinbefore employs three two-position cylinders controlled by three solenoid operated pilot valves, the principle is not limited to this means of control nor only to the three two-position cylinders, nor is the system limited to direct tandem configurations as illustrated herein but may be connected by a system of levers to givemore positions to -the pistons in the cylinders.

I It can thus be shown that the number of operating positions of a cylinder train having a plurality of cylinders each capable of being moved into a plurality of positions is given by the formula :MP, wherein N represents the number of operating positions, M represents th-enumber of positions that the cylinders .are capable of being moved to and n is the number of cylinders utilized. In this example illustrated 'in FIG; 1 therefore, the number of positions N= 2 =8.

It can also be seen that the speed of the cylinder train is the of the individual speeds of each of the cylinders acting, thus enabling a multiplicity of speeds faster than that or" any single unit.

FIG. 1 is designed to be operated with tape read out control such that means unnecessary to an understanding of this invention is operated by atapeto close the different I combinations of three separate solenoids, as previously described. Once these combinations have been closed and the solenoids energized to position the

pilot valves

32, 33 and 3- as desired,-the switches energizing the solenoids may be open and the solenoids deenergized as the pilot valve will remain in that position until a new series of solenoids is, energized to efiect a change in posi tion-ot the guide lug 2?. Othertypes of equipment may be utilized with controls other than tape, such an equip ment as shown in FIG. 3, wherein the apparatus is essentially the same as FIG. 1, however, the pilot valves therein are controlled to one position by a solenoid and to another position immediately upon deenergization of the solenoids by a return spring as will be shown herein-f after. g

Description FlG. 3' The apparatus of FlG. 3 is in part a duplication of the apparatus of FIG, 1 and thus where elements of the apparatus'of FIG. 3 are similar to elements of the apparatus or FIG. 1, similar reference numerals are utilized; FlG.

3 differs from FIG. 1 in that thespool valves (not shown) Laid FIG. 3P0siti0n 2 As seen from the chart in FIG-4, to position the cylinder train in the Position 2, solenoid S5 alone must beenergized, To energize solenoid S5 only; the switch 652 of FIG. 3 is closed to establish a circuit from the battery supply??? and supply wire so through the switch 62 to a Wire 1154, rectifier 155, wire 156 to the solenoid S5 and thence to vground at Wire 1157, thereby energizing the single solenoid S5.

With the single solenoid S5 energized, the spool valves (not shown) of the pilot valve 34 associated therewith are positioned such that the internal passages (not shown) of the pilot valves .32, 33 and Edthereof are controlled by the energization of thesinglie solenoids S1, S3 and S5 to one positi'om'the position wherein the internal passages (not shown) are arranged as indicated by the dotted arrows through the respective pilot valves. With any of g the solenoids Sll, S2 or S3.thereofdeenergizei the spool are arranged as indicated'by the dotted arrows. With fluid flow through the pilot valve 32 in a manner indicated by the dotted arrows 34, the'pneurnatic operation of cylinder 3 is similar to that'of cylinder 3 of ES. 1 in Position 2. In that only solenoid S5 is energized, the spool valves (not shown) of the

pilot valves

32 and 33 will be positioned by the

respective springs

151 and 152 such that the fluid flow therethrough is in the manner indicated by the solid arrows, thereby

conditioning cylinders

1 and 2 in a mannersimilar tothat described in the explanation of FIG. l,Position 2. .Thus,-cylinder 1 will be positioned in its left-most position; cylinder 3 will be I he. 3Positi0n 3' As indicated on the chart of FIG. 4, to position the apparatus-in Position 3, the single solenoid 83' is energized byclosing the push-button switch 63 of FIG; 3 to'thereby and l53-"0f FIG; 3, respectively. Operation of the cylinder train is essentially the same as that of the cylinder train of FIG. 1 therefore a lengthy explanation of the pneumatic operations'is notfelt to be necessary herein. l-lowever, with only the three solenoids S1, S3 and SS re'rnain- Y in'g'in th'eapparatus, new c rcuitry is necessitated as described hereinafter.

To condition the solenoids S1, S3 and S5 of FIG. 3 in the different combinations to provide the diflerent positions of guide pin 29, it is necessary to energize or deenergize the said solenoids in a manner indicated'on the chart of PEG. 4 by closing any one of the switches 62- through as of FIG. 3 to complete circuitry hereinafter j described. As seen from FIG. 4, to position the guide pin 29in the Position 1, all three of the solenoids S1, S3 and S5 are deenergized, a condition easily effected by having the circuitry to said solenoids open. FIG. 3 in Position 1 illustrates a push-button switch or,

said push-button switch serves no purpose in this equipment but is included merely for comparison with the equipment of FIG. 1. With all three solenoids S1, S3 and Although S5 deenergized, the

respective springs

151, 152 and 153.

position the

respective pilot valves

32, 33 and 3d a condition wherein the spool valves (not shown) therein establish internal passages (not shown) that are connected in a manner indicated by the solid arrows on each of the pilot valves. Similar to the operation of the pilot valves of PEG. 1, with the spool valves (not shown) of the pilot valve 32 positioned as indicated by the solid arrows, the

with solenoids S3 and S5 deenergized, the respective piston 8 and cylinder 3 will each be positioned by the

pilot valves

33 and 34 as shown hereinbefore, in their left-most position at Position 1.

complete circuitry as follows: battery'fiifi, supply wire 65?,

' push-button switch es, wire 153, rectif er E59, wire rec to the winding of solenoid S3 and thence to ground at wire 151. This'just-described circuitry'will energize the single solenoid S3 leaving the solenoids S1 and SS'deenergized; Therefore, the spool valves "(not shown) of the pilot valves valves (not shown) of the pilot valve 33 will be positioned due to the energization of solenoid S3 such that the fluid through said pilot valvewill be as indicated by the dotted arrows. With the

pilot valves

32, 33 and 34 so conditioned, the cylinder train apparatus is conditioned in a manner exactly similar to that described hereinbefore under FIG. 1, Position 3, thereby moving the cylinder 1 to its left-most position, the cylinder 3 to its left-most position, and the piston 3 to its right-most position within the cylinder 2 to thereby position the guide pin .29 at Position 3. 7

FIG. 3--P0siti0n 4 As indicated on the chart or 1 16.4, to position the apparatus of PEG. 3 in Position 4, solenoids S3 and 55 must .both be energized by closing the'push-button switch 64 to thereby complete circuitry frornthe battery 59 and supply wire dtl to said push-button switch and thence to wire 162 and two parallel circuits as followsz (a) rectifier 163, wire 156, the winding of solenoid S5 and thence to ground at wire 157; ('0) wire 164i, rectifier 165, wire Edit, to the winding'of solenoid S3 and thence to ground "at wire 1161, thereby conditioning the solenoids S3 and 55 as energizedrand solenoid'sl deenergiz'ed. With the solenoids so conditioned as just described, the spool valves is indicated by, the solid arrows while the spool valves (not shown) of the

pilot valves

33 and 34 are so positioned, due to the energization of the said solenoids,

that fluid flow therethrough is indicated by the dotted arrows, thereby conditioning the cylinder train in a manner exactlyv similar to that described hereinbefore a t is under FIG. 1, Position 4, such that, the will be positioned at Position 4.

FIG. 3----Positi0n 5 As can be seen from the chart of FIG. 4 to condition the apparatus of FIG. 3 in Position 5, the single solenoid S1 must be energized. To energize the single solenoid S1, push-button switch 65 of FIG. 3 is closed to complete circuitry from the battery 59, supply wiretl, push-button switch 65, wire 16 6, rectifier 167, wire 168 to the Winding of solenoid S1 and thence to ground at wire 16%, thereby energizing the winding of. solenoid S1 only, to

guide pin 29 condition the spool valves (not shown) of the pilot valve 33 such that fluid flow therethrough is indicated bythe dotted arrows. The remaining solenoids S3 and S5 are de-energized to permit the

springs

152 and 153 to position the spool valves (not shown) of the

respective pilot valves

33 and 34 such that fiuid flow therethrough is indicated by the solid arrows. With the three pilot valves so conditioned, fluid flow to the cylinder train and conditioning of the cylinder train will be exactly similar to that described under FIG. 1, Position 5,

to thereby position theguide pin 29 at Position 5 FIG. 3'Positi0n 6 the cylinder train for Position .6, the solenoids S1 and S5 mustbe energized by closing the push-button switch v 66 of FIG. 3 to complete a circuit from battery 59 in supply wire 65 to thepush-button switch 66 and thenceto parallel circuitryas follows: (a) Wire 1741, rectifier 171, wire 156 to the winding of solenoid'S5 and thenceto ground at wire 157; (b) wire 1'76, wire 172, rectifier -173,' wire 168 and the winding of solenoidSl and thence to ground at wire 169, therebyenergizing the solenoids S1 and S5 while the solenoid S3" remains deenergized. With. the

three solenoids so conditioned, the spool valves (not cylinder train. in Position 7, the solenoids S1 and S3 must be energized simultaneously by closing the pushbutton switch 67 of FIG. 3 to complete circuitryfrom the battery supply 59, supply wire 60 through said pushbutton switch to parallel circuitry described as follows:

- It can be seen from the chart of FIG. 4 to condition 14 rectifier 179, wire 156, the winding of solenoid S5 and thence to ground at wire 157; (b) wire 1'78, wire 180, rectifier 181, wire 160, the winding of solenoid S3 and thence to ground at wire 161; and (c) wire 178, wire 180, rectifier 182, 'wire 168, the winding of solenoid S1 and thence to ground at wire 169, thereby energizing all' three solenoid valves to position the. spool valves (not shown) of the

respective pilot valves

32, 33 and 34 such that fluid flow therethrough is in a manner indicated by the dotted arrows. With the three solenoids so. conditioned, the cylinder train is conditioned exactly as described hereinbefore under FIG. 1, Position 8, to thereby move the guide pin 29 to Position 8 as desired.

Although only two arrangements of controlling fluid supply and venting-to the cylinder train are discussed herein, other combinations of control by solenoid-operated pilot valves arranged to be energized in difier ent sequences and operating with variations of dilferent types of cylinder trains maypr'oduce other sequences of multipositioning apparatus in a similar manner.

Having now described the invention, What claim as new'and desire to secure by Letters Patent is:

'1. A multi-posit-ion. cylinder apparatus" comprising in combination a plurality of cylinders arranged in a configuration including .a first and second cylinder connected together in tandem and athird cylindenpositionably connected inline with said second cylinder, each of said cylin ders havingajp'iston and piston stem slidably positioned in a bore therein and'f o-rming achamber on opposite sides means connected toeachf of said chambers on opposite sides of each piston in each of the respective cylinders and operabllresponsively to supply of fluid pressure thereto (a) wire 174, rectifier 175, wire 160 tothe winding of solenoid S3 and thence to ground at wire 161; and wire through is indicated by the solid arrows, a condition eX- actly similar to that describedhereinbefore underFIG. 1, j

Position .7 to thereby condition the cylinder train and consequently the guide pin 29 to the Position 7.

FIG. 3Positi0n 8 Ascan be seen from the chart of'FlG; 4, to position the apparatus of P16. 3, Position 8, all three solenoids S1, S3 and S5 must be energized. To energize the three just-mentioned solenoid valves, the push-button switch 68 is closed to complete circuitry from the battery 59, supply wire 60, push-button switch 68, wire 178, and thence to parallel circuitry including: (a) wire 178,

to efiectsupply offluid under pressure selectively to one of said chambers on one side of each of said, pistons and operably responsive to release of fluid under pressure therefrom to effect release of fluid underipressureselecfrom said source to a selective sequence of said delivery means to effect supply of fiuid under pressure to a selec tive sequence of said chambers whereby said cylinders are variably positioned, and a plurality of circuit means each selectively energizing different solenoid-operated pilot valve means in variable sequences to effect supply of fluid under pressure to said delivery means selectively.

2. A multi-positi'on cylinder apparatus comprising in combination a plurality of cylinders arranged in. a configuration including a first and second cylinder connected together in tandem and a third cylinder positionably connected in line with said second cylinder, each ofsaid cylinders having a piston and piston stem slidably positioned in a bore therein and forming a chamber on opposite-sides .thereof in said bore with the ends of the respective cylinders, the piston stem in the said first cylinder extending through an outer end wall thereof to stationary mount- 111g means, the pistonstem in the second cylinder extending. through an outer end wall thereof and through an outer end Wall of the third cylinder toconnect with said piston ofusaid third cylinder in a manner to aline said third cylinder with the said tandemly connected first and second cylinders, a source of fluid under pressure, delivery means connected to each of said chambers on opposite sides of each piston in each of the respective cylinders and operable responsively to variations in fluid pressure there in to enact supply of fluid under pressure selectively to one of said chambers on one side of each of said pistons, a plurality of solenoid-operated pilot valve means operably responsive to energization thereof to one position or a second position selectively for controlling the supply or" fluid under pressure from said source to a selective sequence of said delivery means to cause supply of fluid under pressure to a selective sequence of said chambers sequences to effectsu-pply of fluid snares whereby said, cylinders are variably positioned, and a plurality of circuit means each selectively energizing different solenoid-operated pilot valve means to said one position or saidsecond position in variable sequences to effect supply of fluid under pressure to said delivery means selectively.

3. A multi-position "cylinder apparatus comprising in combinations plurality of cylinders arranged in a configuration including a firstand second cylinder connected r together in tandem and a third cylinder posit-ion ably connected in line with said second cylinder,.each of said cylinder-s having a piston and piston stern slidabiy positioned in a bore'therei'n and forming a chamber on opposite sides thereof in said bore with the ends of the respective cylinders, the piston stern in the said first cylinder extending I through an outer end Wall thereof to stationary mount I ingmeans, the piston stern in the second cylinder extend ing through an outer end Wall thereof and through an third cylinderiini line With the said tandemly connected directional delivery 'means connected to each of said chambers on opposite sides of each piston in each of the respective cylinders and operable responsively to supply of fluid pressure thereto to effect supply of fluid under pressure selectively to one of said charnbers on one side of each of said pistons and operably responsive to release of fluid under pressure therefrom to effect release of fluid under pressure selectively fromoneof said chani cers on one side of each of said pistons, a plurality of solenoid- =first and second cylinders, a source of fluid under pressure,

operated pilot valve means for controlling the supply of fluid under pressure from said source to a selective: se-' under pressure to al...selective; sequence of said chambers whereby said'cylin'ders are 'variablyfpositioried, and a plurality" of. circuitmeans each selectively energizing different solenoid-operated pilot valve means in variable delivery means selectively. i 4. A multi-positioncylinder apparatus as claimed in' claim 3, further characterized in that a fluid pressure re leasetiming means is included in each of said directional delivery means for variably regulating the rate, of release of fluid, under pressure from the said chamber of said 1 cylinder to which said delivery means is connected.

tioned ina' bore therein and forming a chamber on opposite sides thereof in said bore with the ends of the respective cylinders, the piston stem in the said first cylinder extending through an outer end Wall thereof to stationary mounting means, the'piston stem in the second'cyl-f inder extending through an outer end Wall thereof and through an outer end all of the third cylinder to connect with said piston of said third cylinder in a manner to al-ine said third cylinder With the said tandemly connectedfirst and second cylinders, a source of fluid under pressure, delivery means connected to each of said chain'- bers on opposite sides of each piston in each of the respective cylinders and operable responsively to variations in fluid pressure therein to etfect'suppl'y of fluid under pressure selectively to one of said chamber-s on one side of each of said pistons, a plurality of solenoid.- operat'ed pilot valve means each operably responsive to energization thereof to one position to effect supply of under pressure to said fluid under pressure from saidsource to one of said delivery means and a plurality of spring means each operably responsive to deenergization of one of said pilot valve means to position each of said pilot valves in a second position to eflect release of fluid under pressure from one delivery means.

6. Multi-position cylinder apparatus comprising in combination: t

(a) a plurality of coaxialiy related cylinders,

(b) a piston sliclablyoperable in each of said cylinders and having a stern extending slidably through one end of the cylinder tolthe exterior thereof,

' (c) the piston stem of one of said cylinders being pivotally anchored to a fixed point,

(d) a second one of said cylinders being secured to said one cylinder and the piston stem of said second cylinder and that of a third one of said cylinders being connected together, and p V (e) means for effecting supply and release of fluid under pressure selectively to andfrom chambers at opposite sides of the pistons in said cylinders to cause movement of said third cylinder with respect to the fixed point selectively to any one of a plurality of different uniformly space positions, said means comprising: i r

(i) individual conduit 'me'anss for each of said chambers via which fluid under pressure is'supplied theretoifrom a source of fluid pressure sup- P y v '(ii) pilot valve means operative in one position to connect the corresponding conduit means to l thesource of supply and operative in another position to disconnectthe conduit'nieans from r the source of supply and vent theconduit means I to atmosphere,( (iii) check valve means interposed in each of said conduit means through which fluid under pressure is supplied at a rapid ratetoward the cor-' responding chamber and which prevents reverse flow of fluid under pressure therethrough,

(iv) choke means in parallel relation with each of said check valve means through which restricted :reverse' flow of fluid under pressure in the con- Pseterenees'fited by the Examiner UNITED STATES PATENTS 2,010,158 8/35 Kleinschrnidt et al. r12l38. 3 2,980,063 4/61 Litz 121-38.3

7 3,072,146 1/63 Gizeski 121-383 I ornaa REFERENCES tHydraulic Handbook; published by Trade and Technical Press, Ltd, Morden Surrey, England, 1960, page 368.

FRED 'n. ENGELTHALER, Primary Examiner. SAMUEL Lav na, xaminer;

Claims

1. A MULTI-POSITION CYLINDER APPARATUS COMPRISING IN COMBINATION A PLURALITY OF CYLINDERS ARRANGED IN A CONFIGURATION INCLUDING A FIRST AND SECOND CYLINDER CONNECTED TOGETHER IN TANDEM AND A THIRD CYLINDER POSITIONABLY CONNECTED IN LINE WITH SAID CYLINDER, EACH OF SAID CYLINDERS HAVING A PISTON AND PISTON STEM SLIDABLY POSITIONED IN A BORE THEREIN AND FORMING A CHAMBER ON OPPOSITE SIDES THEREOF IN SAID BORE WITH THE ENDS OF THE RESPECTIVE CYLINDERS, A SOURCE OF FLUID UNDER PRESSURE, DIRECTIONAL DELIVERY MEANS CONNECTED TO EACH OF SAID CHAMBERS ON OPPOSITE SIDES OF EACH PISTON IN EACH OF SAID CHAMBERS ON OPPOSITE OPERABLE RESPONSIVELY TO SUPPLY OF FLUID PRESSURE THERETO TO EFFECT SUPPLY OF FLUID UNDER PRESSURE SELECTIVELY TO ONE OF SAID CHAMBERS ON ONE SIDE OF EACH OF SAID PISTONS AND OPERABLE RESPONSIVE TO RELEASE OF FLUID UNDER PRESSURE THEREFROM TO EFFECT RELEASE OF FLUID UNDER PRESSURE SELEC-