US2620777A - Hydraulic control system for hydraulic piston type control valves - Google Patents

Description

J. M. ToWLER ET A1. .HYDRAULIC CONTROL SYSTEM FOR HYDRAULIC Dec. 9, 1952 PIsToN TYPE CONTROL VALVES Filed dem. 15, 1946 `5 Sheets-Sheet l Dec. 9, 1952 J. M. TowLER ET AL 2,520,777

HYDRAULIC CONTROL SYSTEM FOR HYDRAULIC PISTON TYPE CONTROL VALVES Filed Jan. l5, 1946 5 Sheets-Sheet 2 MIb-MM Dec. 9, 1952 J. M. Towll-:R ETAL 2,620,777

HYDRAULIC CONTROL SYSTEM FOR HYDRAULIC PISTON TYPE CONTROL VALVES Fled`Jan. 15, 1946 3 Sheets-Sheet 5 man., q i 48 49 Atto/neg Patented Dec. 9, 1952 UNITED STATE S PATENT vOFFICE HYDRAULIC CONTROL SYSTEM FOR HY- DRAULIC PISTON TYPE CONTROL VALVES lApplication January 15, 1946, Serial No. '641,300 In Great Britain February 5, 1945 7' Claims.

This invention relates to hydraulic control systems for control valves of the piston type for controlling the supply of pressure liquid to the hydraulic cylinder or cylinders of a hydraulic press.

One object of this invention is to provide means whereby such a control valve can be made to operate a hydraulic press on an automatic cycle so that when the operatorV moves the valve lever into the operative position, the press ram makes anV operating stroke and when it comes into contact with the work the pressure inthe press cylinder builds up to a predetermined pressure at which the valve lever`is`tripped or when the press ram reaches a vpredetermined position it strikes tappets which actuate" thetripv either hydraulically or mechanically and the Valve spindle or plunger is automatically 'reversed so as to terminate the delivery of pressure liquid to the press cylinder and connect it toexhaust and admit pressure liquid to the return cylinders or annulus in order to effect the' return stroke of the press ram.

A further object of this'invention is to provide means Wllereby the movement of `the control valve spindle or plunger shallbe completely 'controllable by the'op'erator until such vtime as 4the predetermined pressure orpredetermined stroke is reached `so that the press'ram can be inched on the operative stroke or 'reversed by the operator `before ythe trip comes into operation. This invention may be applied with equal iacility'to a single'acting piston 'type control valve `for controlling the supply of pressure liquid to a press cylinder so that when a predetermined pressure is reached the supply of'pressureliquid tothe cylinderisterminated and the cylinder'is connected to exhaust so that the return stroke of the press ram can be effected-by means of springs or vdraw-back weights or a 'constant pressure push-back ram or annulus.

Broadly the present invention consists ofL an hydraulic'c'ontrol Valve vczftltcepiston type wherein the'valvep'iston is operable manually against 'an opposing spring or other pressure to admit pressure liquid to a press or other hydrauliccylinder and wherein automatically operating means is provided to 'disconnect the manual operating means from the valve plunger whenv either a predetermined pressure in the' press vcylinder is reached or a predetermined strokeV of the press ramy has taken place to permit the opposing spring or other pressure to move Vthe valve plungerin' the' opposite direction to' a neutral vor other position for 'ricturningv the press. ramv or other operation.

2 In order 'that' the invention may Vbe clearly understood and carriedin'to eiect an embodiment of the same, as applied tothe control'valve illustrated in Figs. I and" 2 of the U. S. Letters Patent 2,361,801 of October 3l, 1944, will now be described', 'by Way of example, by aid of the accompanying drawings in which:

Fig. 1 is a longitudinal section Vthrough the valve which is' constructed for use in connection with a double-acting hydraulic cylinder.

Fig.` la 'is'a' detail hereafter to be described.

Fig. 2.is a transverse vertical section taken at right angles to Fig. 1.

Fig. 3 'is' adiagram illustrating one arrangement in which the operating lever of the control valve is tripped when the' hydraulic ram of a press or other mechanism reaches a predetermined position in` its "stroke.

Fig. Saris' a longitudinal sectionalview of a valve operated by the press ram.

Fig. 4 is a diagram similar to Fig; 3, but illustrating a modified arrangement vin Which the control valve .is tripped when a' predetermined pressure is attained in the `ram cylinder.

Referring now to Figsi l and 2 of the' drawings the valve illustrated" comprises a valve body a, preferably of hardened steel, 'having a parallel bore to'receive 'the plunger b','which is also preferably of hardened steel. The bore of Ythe valve body, in which the'piston'is a close sliding rit, isv enlarged interiorly to form ve chambers, which arenumbered from left to right, 2, 3, il, 5. Thus; the bore of the valve body' is therefore divided into six narrow bands,'which are numbered 6,1; 8,'9, AIll'and Il, `from left to right. The bands l; 8, 9 and I0 separate the chambers i, 2, 3, 4, 5 and the bands 6 and Il are disposed at each end of the valve body.

Chamber number I is connected Ato Vthe pump through inlet lla, chamber number 2 is connected to vexhaust'by outlet 2a, chamber number 3 is connected by outlet v3a to one side of the hydraulic piston'andcylinder, chamber number' l is connected throughpassage d and non-returnvalve e to chamber number I`in such a Way that liquid may pass yfromV chamber'number i" past the nonreturn valve to chamber number 4, but not`in a reverse direction; chamber number disconnected to the other side of fthe hydraulic piston and cylinder through outlet A5a. 'The valve plunger passes right through the valve `body and' protrudes at each end into spaces f and g and suitable cover platesare provi'ded'to" enclose such spaces" and these'spacesl are `connectedto the exhaust outlet Zdyleading 4b'ackto the pump reservoir, 4so that -the valve 'piston is at all times hydraulically balanced, and suitable manually operable means such as lever h is provided to move the valve plunger longitudinally.

In the embodiment of the present invention now to be described the plunger b is moved longitudinally by turning the lever h about its pivot. This pivot consists of a pin I2, see Fig. 2, on the outer end of which is mounted the operating lever 71 and on the inner end of which is mounted a short lever I3 the upper end of which is provided with a pin I4 which normally engages within a circumferential groove I5 at the right hand end of the plunger b. So far the construction is similar to that employed for operating the valve plunger in the control valve illustrated in the drawings accompanying the aforesaid U. S. Patent 2,361,801.

For the purpose of the present invention this construction is modied so that when a predetermined pressure is reached within the hydraulic cylinder under control the pin I4 is automatically disengaged from the circumferential groove I5 .thereby freeing the plunger b from its manual control and permitting a spring If, arranged to oppose the manual operation of the valve plunger in one direction, to return said plunger to a ncutral or other predetermined control position.

The modification thus required, consists, in the illustrated arrangement, in mounting the pin I4 on the end of the short lever I3 and attaching this lever to the inner end of the pivot pin I2 of the lever h by means of a pivot connection I1 so that the upper end of the lever I3 is free to swing and move the pin I4 into and out of engagement with the circumferential groove I5. This freedom of movement is, in practice, restrained by a spring plunger I3 which bears against the pivoted lever I3 at a point just above its pivot so that the plunger I8 tends to force the lever towards the valve plunger and maintain the pin I4 in engagement with the aforesaid groove I5. The valve plunger is thus free to be moved through its bore, under the control of the lever h, thereby to admit pressure liquid to either end of a double-acting hydraulic cylinder.

When the pressure in the hydraulic cylinder reaches a predetermined maximum (Fig. 4) or when its ram reaches a predetermined position in its stroke (Fig. 3) it is the object of the present invention to ensure that the plunger of the control valve shall be freed automatically from its manual control and returned to a neutral exhausting position, or another pressure liquid delligfery position, under the influence of the spring For this purpose the lever I3 is provided with a projection in the form of a short rigid lever I3 having a ball-end which rests upon the upper end of a vertical hydraulic plunger 2 I. Pressure liquid is admitted to the lower end of the plunger through an inlet 22 and the upward movement of the plunger under the pressure of said liquid is limited by a stop comprising an enlargement 23 in the length of the plunger and a dead stop 24 the length of which is suitably adjusted during the testing of the valve. The area of the plunger that is subject to the liquid pressure is such as to enable said pressure to move the plunger upwards and tilt the lever I3 backwards against the restraining action of the spring plunger I8.

When the plunger has moved into contact with its stop the pressure liquid acting against its lower end may be automatically released into the space g at the end of the valve piston through a passage 25 extending up through the plunger from its lower end and radial passages 26 serving in the fully raised position of the plunger to provide a communication between the upper end of the passage 25 and the space g. This feature is however not essential and may be omitted.

The means for holding the valve lever in the extreme position consists of a detent in the form of a spring plunger 21 extending up through the lever and having a pointed lower end engageable in said extreme position in a notch or recess in the circumference of a quadrant 28. Here again, this feature is not essential and may be omitted.

If the operation to release the plunger of the control valve is to be dependent upon the attainment of a predetermined pressure in the hydraulic cylinder then the supply of pressure liquid to the plunger 2I, may, as previously explained, be controlled by a master control valve 53, or any other suitable form of control valve but when the release of the plunger of the control valve is to be dependent upon the press or other ram reaching a predetermined position then the control of pressure liquid to the plunger 2I may conveniently be effected by a small valve operated by tappets on the press or other ram.

One suitable arrangement for this purpose controlled by the movement of the ram is illustrated in Fig. 3 in which A indicates the control valve of the present invention, B the press ram, and C the tappet operated valve.

In the illustrated arrangement the valve C is interposed between the press cylinder and the inlet 22 to the small ram 2| of the control valve and said valve is connected by the pipe 29 to the pressure delivery pipe 30 for supplying pressure liquid to the press cylinder, by the pipe 3l to the inlet 22 for by-passing some of the pressure liquid from the delivery pipe 30 to the inlet 22 for operating the plunger 2I and to exhaust by way of pipe 32. The valve C may be of any suitable character normally adjusted to block the control line 3I from the pressure line 29 and connect it to the exhaust line, and adapted for actuation to block the control line 3I from the exhaust line 32 and connect it to the pressure line 29. In the form illustrated, the valve C comprises a housing 39 adapted to be supported in xed position with a pivoted valve actuating tappet 34 thereon disposed in the path of a rigid tappet 33 carried by the press ram B. The housing 39 is formed with a valve bore 40, chambers 4I and 42 open to opposite ends of the bore and connected to the exhaust line 32, and axially spaced annular grooves 43 and 44 formed in the surface of the bore and connected respectively to the lines 29 and 3l. A valve plunger 45 of the spool type is reciprocable in the bore 40, and is formed with two peripheral axially-spaced grooves 4G and 41, the groove 41 being open through a passage 48 in the plunger to the exhaust end chamber 4I. A compression spring 49 acts against a shoulder 50 on the plunger 45 within the chamber 4I to urge the latter normally into closed position in which the port 43 is blocked and the port 44 is connected through the groove 41 and passage 48 to the chamber. The tappet 34 comprises an arm having a fixed pivot pin 5I rotatable in the housing transaxially of the valve plunger 45. A radial pin 52 is fixed in the pivot pin 5I and extends therefrom transversely across the end face of the plunger 45 within the chamber 42. Upon downward actuation of the tappet 34, the pin 52 will depress the valve plunger 45 against the force of the spring 49 to move the groove 41 out of communication with the port `44 yandfto connect the latterfthrough Vther-groove 46 with the -port"'43. Thevalve C .is operated when the rigid tappet 33 carried by the press ram strikes the pivoted'tappet 34 "forming the operatinglever ofthe valve; in the downward direction to cause pressure liquid to low `to the inlet 22 to eii'ect the release of the plunger of the control valve A from its operating. lever by actuation of the plunger 2l and in the upward direction or return stroke. of ythe press ram to connect the inlet`f22 Vto exhaust thereby to permit the operating lever h 'of the control valve .Ay to be reconnected with 'the plunger of said control valve.

At very high pressures, for example, two to three tons per square inch, it may be 'found that the valvespindle has a tendency to stick and refuse instantaneously to move under the innuence of thespring i6. This, of course, maybe overcome by tting asufhciently strongspring but to ensure certainty of action a more positive means may be provided One such means is shown in dotted lines inF'ig. la which is a modication of the right hand end of Fig. 1 and consists lof a small hydraulic plunger'35, similar to the plunger 2 I, which is adapted to give the valve plunger b an initial push after the valve lever has been disengaged. VThe plunger 35 operates in a cylinder 35, which is fitted in the end of the housing for the spring I6, and pressure liquid is supplied thereto, for example from'the line 3l Athrough a line 38, at the same time as it is supplied to inlet 22 for the plunger 2 l. A spring 3l is provided to opposethe inward movement of the plunger -35 and this spring is stronger than the spring acting on the plunger I8 which opposes the inward movement .of the other plunger 2l so that the movement of the plunger 35 will occur later than that of the plunger 2l, i. e. after the valve lever has been disengaged from the valve plunger l).

A modified arrangement controlled by the master .control valve 53 aforesaid is disclosed in Fig. 4, and, to the extent that it compares with the arrangement of Fig. 3, corresponding ports are identified by the same reference characters but primed. In this arrangement, the master control valve 53 may be of any suitable character having the same general functions as the tappet operated Valve C, but operable in response to a predetermined pressure in the line 553 rather than by-mechanical actuation from the ram B. More particularly, the valve 53, in the exemplary form disclosed, comprises a housing 54 formed with a valve bore 55 and axially- spaced ports 56 and 57 connected respectively to the lines 29 and 3l. One end of the valve bore 55 opens to a chamber 53 connected to the exhaust line 32, and the other end thereof is connected through a passage 5g to the port 55 and line 2S. A spool type valve plunger El) is reciprocable in the Vbore E5, and exposed at one end to the iluid pressure in the passage 59. At the other end, the valve plunger E5 is acted upon by a coiled compression spring 6I located within the chamber 58. "The arrangement is such that normally the valve plunger 5E) is positioned to block vthe port 5l". and line 3l' from the port 55 and line 25', `andv 5to `connect theport 5l to the chamber 58 and exhaust line 32. However, upon the attainment of a p-redetermined pressure in the line 2Q', this pressure acting upon the end face of the valve plunger 60 will shift the latter in opposition to the spring 6| so as to block the control port 5l from the exhaust chamber 58, and connect the ports :56 and 51. Thereupon, the pressure transmitted-fromthe line 29f-to the. line 3l willrelease the control valve A for movement into reverse'position. Asfsoon as reversal of pressure in the lines 29 and'30is effected to initiate the-return stroke ofthe rain-B', the valve 53 Will return automatically to normal position.

We claim:

1. An hydraulic'control'system for an hydraulic control valve comprising a Valve-body having a bore, a valve plunger slidable in saidbore for control-ling the distribution Vof pressure liquid to andfrom an. hydraulic cylinder, manually operable-means for imparting longitudinal movement .to 'said valve plunger, said means comprising a hand :lever mounted on one end of a pivot pin and a pivoted lever'on the other end Aof said pivot pin, acircumferential groove in the valve plunger, aV pin carried by the outer end 'of said` pivoted lever 'forengagement with said groove, resilient means acting against said pivoted lever to maintain its4 pin iin engagement with said groove, an hydraulically voperated plunger for turning said pivotedilever against said resilient means to disengage its pin from said circumferential groove when pressure liquidis admitted to said plunger, valve means operating automatically upon attainment of a predetermined condition to admit pressure liquid to said plunger, and'spring loading means for opposing .the longitudinal movement 4of the valve'plunger in its bore in one direction and for returning said plunger automatically to its normal position when freed from engagement with said manually operable means.

2. An hydraulic control'system for an hydraulic control valve comprising a valve body having a ported valve bore, a'valve plunger slidable longitudinally in said bore for controlling the distribution of pressure liquid to and from `an hydraulic cylinder, manuallyoperable means for imparting the longitudinal `movement to said valve plunger, disengageable means normally connecting said manually operable means operativelyto said plunger, actuatingmeans operated hydraulically to act `on -said disengageable means for eifecting automatically disengagement between said manually operable means and the vvalve plunger, valve means operating automatically uponattainment of a predetermined condition to permit the pressure fluid to said actuating means to cause said disengagement, a load which opposes longitudinal movement of the valve plunger'in one direction andV which acts `automatically when the valve plunger is released to return said plunger to its normal position, and an hydraulically operated'plunger operable to give an initial impetus ,tothe valve plunger after release from said manually. operable means .to prevent the valve plunger from sticking.

3. An hydraulic control system for an hydraulic control valve according to claim l, wherein the valve plunger after its release from the manually operablemeans is given an initial impetusby means ror -a yhydraulically loperated plunger to .prevent the lvalve plunger from sticking and wherein theplunger forgiving saidinitial impetus tothe-valve plunger is opposed by a spring that `is stronger than thespring which opposes the plunger servingto eiect disengagement 'of the manual operating means from the valve plunger to ensure that said former plunger although receiving liquid at the same time as the other plunger will operate after said disengagement has been eiected.

4. An hydraulic control system for an hydraulic control valve comprising a valve body having a bore, a valve plunger slidable in said bore for controlling the distribution of pressure liquid to and from an hydraulic cylinder, manually operable means for imparting longitudinal movement to said plunger, said means comprising a hand lever mounted on one end of a pivot pin and a pivoted lever on the other end of said pivot pin, a circumferential groove in the valve plunger, a pin carried by the outer end of said pivoted lever for engagement with said groove, resilient means acting against said pivoted lever to maintain its pin in engagement with said groove, an hydraulically operated plunger for turning said pivoted lever against said resilient means to dis-engage its pin from said circumferential groove when pressure liquid is admitted to said plunger, a tappet valve adapted to be operated when a ram in the hydraulic cylinder has made a predetermined stroke to pass pressure liquid to the hydraulically operated plunger to effect th-e turning of the pivoted lever, and spring loading means for opposing the longitudinal movement of the valve plunger in its bore in one direction and for returning said plunger automatically to its normal position when freed from engagement with said manually operable means.

5. An hydraulic ,control valve comprising, in combination, a valve body having a valve bore, a spool valve plunger slidable in said bore in porting relationship therewith for controlling the distribution of pressure fluid, spring means tending to bias said plunger longitudinally in one direction into one distributive position of adjustment, manually operable means disengageably connected to said plunger and being operable to shift said plunger in opposition to said spring means into another distributive position of adjustment, said manually operable means comprising a hand actuator on said body, a latch movable into and out of engagement with said plunger and connected to said actuator for movement thereby to effect longitudinal movement of said plunger when in interlocking engagement therewith, and spring means normally acting on said latch in a direction to effect said interlocking engagement, and hydraulically operable means having a cylinder adapted for connection to receive pressure fluid and a piston therein arranged to act on said latch in opposition to said last mentioned spring means and being responsive to the supply of pressure fluid thereto to effect automatic disengagement between said manually operable means and said plunger for actuation by said rst mentioned spring means.

6. An hydraulic control system for an hydraulic control valve comprising a valve body having a bore, a Valve plunger slidable in said bore for controlling the distribution of pressure liquid to and from an hydraulic cylinder, manually operable means for imparting longitudinal movement to said plunger, said means comprising a hand actuator mounted on a rock pin and a pivoted lever mounted on said rock pin for swinging movement transversely of said plunger and releasably engageable therewith to slide the latter positively in either direction upon reverse adjustment of said actuator, resilient means acting against said pivoted lever to maintain it in interlocking engagement with said valve plunger, an hydraulically operated plunger for turning said pivoted lever against said resilient means to disengage it from said valve plunger when pressure liquid is admitted to said hydraulically operated plunger, a tappet valve adapted to be operated when a ram in the hydraulic cylinder has made a predetermined stroke to pass pressure liquid to the hydraulically operated plunger to effect the turning of the pivoted lever, and spring loading means for opposing the longitudinal movement of the valve plunger in its bore in one direction and for returning said plunger automatically to its normal position when freed from engagement with said manually operable means.

7. An hydraulic control valve comprising, in combination, a valve body having a valve bore, a spool valve plunger slidable in said bore in porting relationship therewith for controlling the distribution of Pressure fluid, spring means tending to bias said plunger longitudinally in one direction into one distributive position of adjustment, manually operable means disengageably connected to said plunger and operable when engaged therewith to shift said plunger synchronously in either direction, including said one direction and also the reverse direction to shift said plunger in opposition to said spring means into another distributive position of adjustment, said manually operable means comprising a rock shaft journalled in said body, a hand actuator secured to said rock shaft, a latch element connected to said shaft for actuation thereby and movable into and out of operative connection with said plunger, and spring means normally acting on said latch element to establish said operative connection, an hydraulically operable means having a cylinder adapted for connection to receive pressure fluid and a piston within said cylinder arranged to act on said latch in opposition to said last mentioned spring means to interrupt said operative connection and being responsive to the supply of pressure fluid to said cylinder, whereby the supply of pressure fluid to said cylinder when said plunger is in said one distributive position will effect automatic disengagement between said manually operable means and said plunger and thereby permit said plunger to be shifted by said first mentioned spring means out of said one distributive position.

JOHN MAURICE TOWLER. FRANK HATHORN TGV/LER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,156,855 Akans Oct. 12, 1915 1,230,150 Geraghty June 19, 1917 1,768,275 Urton June 24, 1930 1,907,538 Hanna May 9, 1933 2,070,720 Ernst Feb. 16, 1937 2,246,379 Muir June 17, 1941 2,263,470 Perkins Nov. 18, 1941 2,311,010 Vickers Feb. 16, 1943 2,361,801 Towler Oct. 31, 1944 2,433,719 Van Sittert Dec. 30, 1947

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