US2519900A

US2519900A - Control circuit for multiple hydraulic press systems

Info

Publication number: US2519900A
Application number: US64472A
Authority: US
Inventors: George M Geiger; Philip J Lindner
Original assignee: HPM Development Corp
Current assignee: HPM Development Corp
Priority date: 1948-12-10
Filing date: 1948-12-10
Publication date: 1950-08-22
Anticipated expiration: 1967-08-22

Description

Aug. 22, 1950 G. M. GEIGER ET AL CONTROL CIRCUIT FOR MULTIPLE HYDRAULIC PRESS SYSTEMS Filed Dec.

George M 6121967 53% P/zz'l J lz'ndnefi attorn y Patented Aug. 22, 1950 CONTROL CIRCUIT FOR MULTIPLE HYDRAULIC PRESS SYSTEMS George M. Geiger and Philip J. Lindner, Mount Gilead, Ohio, assignors to H-P-M Development sCorporation, Mount Gilead, Ohio, a corporation of Delaware Application December 10, 1948, Serial No. 64,472

Claims.

This invention deals with fluid-pressure-actuated apparatus, and in its more specific aspects, with hydraulic control circuits for hydraulic presses or similar fluid-actuated apparatus.

The present invention has as its primary object the provision of an improved control circuit for multiple hydraulic press systems, wherein a plurality of presses are operated by pressure fluid displaced by a single hydraulic pump, and wherein the individual control circuits of the presses are so arranged as to be locked-01f from the remainder of the control circuits, in order that the control circuit of each individual press may operate independently of the remaining press-controlling circuits in the same manner as if each press-control circuit were supplied pressure fluid by separate pumping stations.

It is another object of this invention to provide a control circuit for a multiple hydraulic press system which make possible the operation of a plurality of presses in any desired order or sequence from a single pumping station without fear of interference with the operation of any one of the plurality of presses by the operation of another press in the circuit.

It is a further object of the invention to proconduit I0, and at its opposite end with a safety pressure relief valve H which functions in response to a predetermined maximum pressure within the supply line 9, to return fluid displaced by the pump to th reservoir 5. Disposed at one end of the main pressure manifold It is a solenoid-operated two-Way unloading valve l2, by which pressure fluid within the main'pressure manifold it may be selectively exhausted to the reservoir 5. V

' Connected at intervals along the length of the manifold) are a plurality of separate branch conduits 13 in which are interposed check valves is which function to permit the flow of fluid in a direction from the pressure manifold Hi only.

.Connected to the outer ends of the branch conduits i3 are the fluid inlet ports {5 of a plurality of four-way distributing valves it. In the usual manner, the valves IS, in addition to the fluid inlet ports i5 are provided with fluid outlets or exhaust ports ii, and first and second motor ports l8 and i9 respectively.

vide a control circuit for a multiple hydraulic press system which embodies a pluralit of pressactuating hydraulic motors or rams each of which is provided with advancing and retracting means to which pressure fluid may be supplied simultaneously during the pressing strokes of the presses, in order to provide positive hydraulic pressure on both sides of the pistons or plungers of the motors to prevent slippage or leakage within the motors during pressing operations.

For a. further and more detailed understanding of the present invention, and the various additional objects and advantages realized therefrom, reference is made to the following description and the accompanying drawing, wherein, the single figure is a circuit diagram disclosing the multiple press control circuit of the present invention.

Referring to the drawing, the present invention makes use of a liquid reservoir 5 in which a supply of hydraulic fluid is maintained to supply the various fluid-actuated elements of the present control circuit, to be hereinafter more fully described. Extending within the reservoir 5 is the intake line 6 of a variable displacement uni-directional fluid pump 1 having an output line 8. The output line 8 of the pump is connected with a supply conduit 9 which, in turn, is connected at one'end with a pressure manifold vancing area 3!.

the armatures of solenoids 22.

Internally, the four-way valves it are provided with longitudinally slidable spools 'or plungers 26 having end shafts 2| extending externally of the valve casing and connected with The plunger 20 of the valve is normally spring-pressed to a neutral position by means of coil springs 23, interposed between the ends of the plunger 2t and the end walls of the valve casing, and upon selective energization of the associated solenoids 22, the plunger is moved to positions providing for the introduction of pressure fluid to either of the motor ports l-S and it while connecting the opposite motor port with the exhaust outlet ll.

Communicating with each of the motor ports 13 of the valves I6 is one end of a supply conduit 24 which has its opposite end communicating with the retracting chamber 25 of a fluidpressure-responsive motor or hydraulic ram 25.

Each motor or ram 26 comprises a cylinder 2? formed with an internal cylinder bore in which is reciprocably mounted a piston plunger 28 having a ram-retracting pressure surface or area 2%, a primary advancing area 36, and a booster ad- The cylinders 27of each ram are provided internally with dome-shaped end chambers 32 through which extends an axially disposed stationary booster plunger 33 formed with an axial passage through which pressure fluid may be introducted to react upon the boosteradvancing area 3| of the piston plunger. The end chamber 32 of the cylinder 2? is provided with a pair of inlet ports 34 and 35 through which fluid may be introduced to the end chamber or the cylinder to react upon the primary advancing pressure area of the piston plunger 28. Connected with the inlet port of the end chamber is a conduit 35 in which is interposed a suction check valve 31 which functions to permit fluid contained within a, gravity-fed manifold 38 to be drawn inwardly of the end chamber 32 as the piston plunger 28 advances under action of the booster plunger 33 to prefJl the primary advancing means of the motor.

Connected with the second motor port I9 of the valve 16 is a supply conduit 39 which is connected at its opposite end with the bore or the stationary booster plunger 33. Communicating with the fluid inlet port 35 of the cylinder 21 is a supply conduit 40 which has its opposite end communicating or connected with the motor port n of a three-way solenoid-actuated valve 42. The valve 42 is provided with a fluid inlet port 43 which is connected, by means of a branch conduit 44, with the supply conduit 24 leading from the motor port 18 of the valve In to the retracting area of the individual motors 2B. The three-way valves 42 are further provided with fluid outlet or exhaust ports 35 which are connected with an exhaust manifold as having a return conduit 41 extending within the reservoir 5. The valves 42 are operable to selectively direct pressure fluid from thesupply conduits 24 to the conduits 40 associated with the main advancing area of the motors, or to connect the conduits 40 and the advancing areas of the motors to exhaust by way of the exhaust manifold 46 and are preferably spring-pressed, by means of springs 42a to a position establishing communication between the conduit 40 and the exhaust port 45, with the solenoid 42b functioning upon energization to shift the valve to its opposite position.

interposed within each of the conduits 40, be-

tween the valves 42 and the primary advancing area of the motors 28, is an adjustable pressure reducing valve 48 which is operable to variably rediice the pressure of fiuid passing from the valve 42 to the primary advancing areas of the piston plii'ngers 2'8. Disposed in by passin'g relation to the pressure reducing valves 48 are check valves a providing for the passage of fluid in a direction away from the motors and toward the valves 42.

Thus, it will be seen, that as the distributing valves it are individually conditioned to introduce pressure fluid within the conduits 24, such fluid will normally be introduced within the retractin'g area of the motors, but as the valves 42 are opened, the pressure fluid is simultaneously introduced within the primary advancing areas of the motors, and advancing movement of the piston plunger 28 will ensue, due to the fact that the advancing area 30 is substantially greater than the retracting area 29 of the piston plungers. The pressure reducing valves 48 associated with the primary advancing areas of the motors unction to control the pressure of fluid introduced within the primary advancing areas of the motors, in order to determine the force exerted through the piston plunger 28 to 'a press platen 49 carried at the outer end thereof.

In operation, assuming the piston pluhg'ers 28 to be in their inner-most retracted positions, as shown in the drawing, the press cycle is begun by conditioning one of the valves IS SO as to direct pressure fluid from the pressure manifold 18 into the supply line 39 associated with the booster" advancing area of the motors. At this time,

the retracting area of the motor will be opened to exhaust by way of an exhaust manifold Ila, thereby allowing the piston plunger 28 to advance rapidly under action of the booster advancing means. In the usual manner, the booster ad- 'vancing plunger is utilized to speed the extension of the piston plungers into engagement or near engagement with the work objects, and as the platen 49 carried by the piston plungers of the motor approaches the work, the valve [6 is shifted so as to direct pressure fluid through the supply line 24 and to connect the booster advancing area to exhaust. Simultaneously, the valve #2 is conditioned by energizing solenoid 421) so as to connect the primary advancing area of the motor with the supply line 24 whereby pressure fluid may be introduced simultaneously into both the retracting area and the primary advancing area of the motor, at which time the piston plunger 28 moves in its pressing power stroke due to the differential in pressure area between the retracting area 29 and the primary advancing area 30. The provision of positive fluid pressure on either side of the head of the piston plunger 28 insures a liquid-tight seal on either side of the head, and prevents the passage of pressure fluid around the sides of the piston plunger during its final pressing stroke.

As the piston plunger and platen reach their outermost position of extension, and the pressing stroke is finished, th'evalve 42 is conditioned by (lo-energizing solenoid 42b so as to open the primary advancing area of the motor to exhaust, at which time the piston plunger 28 will retract under pressure of fluid introduced to the 'retracting area of the motor to once again return the piston to its innermost retracted position.

In this connection, it is important to note that during any stage of the operation, of any one motor, another of the multiple circuits may be cut in to actuate another ram or motor without fear of diminishing the operating pressure within the remaining press circuits, due to the fact that the check valves 14 will function to hold whatever pressure is within the individual motor control circuits, to prevent the release of pressure backwardly through the pressure manifold I0 upon operation of another press circuit. Hence the present control circuit is particularly advantageous with respect to sequential press operations which require that one press after another be operated to one cycle of its overall operation and stopped whereupon another oncuit is cut-in to condition another press for its particular cycle; it being understood that if a pressure stroke is completed within one press, such ress may be held in its extended position without rear of slippage, due to the function of the check valves M, and their creation of a look within the individual circuits. I

In view of the foregoing it will be seen that the present invention provides an improved and efficient control circuitfor a multiple hydraulic press system which utilizes but a single fluid displacement pump to supply pressure fluid to the individual press circuits for variable sequential operation. Through the provision of the pressure manifold and check valve system, the indi- 'vidual press-actuating motors or rams may be controlled independently of the remaining pressactuating rams in a manner to complete any partic'ular sequence or cycle of the ram operation, without fear of interference with such operation actuation of another of the ram circuits of the press system.

ass-grab Controlcircuits formed in accordance with the present invention are further characterized by their structural simplicity, ease of operation and their economy of manufacture, maintenance and operation. 1 a

While a single preferred embodiment of the present invention has been disclosed in detail, it will be manifest that various modifications as to constructional details are possible without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. In a hydraulic control circuit for a multiple station hydraulic press system; a plurality of hydraulic motors each comprising a cylinder, 2. piston plunger reciprocable in said cylinder and having a primary advancing area, a, retracting area and a booster advancing area, and means to introduce fluid to each of said areas; a source of fluid pressure; a pressure manifold to receive fluid pressure from said source; a, plurality of first valves separately connected with said pressure manifold to selectively direct pressure fluid to ither the retracting area or the booster advancing area of each of said motors while connecting the other to exhaust; a plurality of second valves connected between said first valves, the retracting areas of said motors, and the primary advancing areas of said motors to selectively direct pressure fluid to the primary advancing areas of said motors simultaneously with the introduction of pressure fluid to the retracting areas of said motors or to connect the primary advancing areas of said motors to exhaust; and check valves interposed betwe n each of said first valves and said pressure manifold to prevent" the return of fluid from said first valves to said manifold.

2. A control circuit for a multiple station hydraulic press system, comprising a plurality of fluid-pressure-actuated motors each embodying a cylinder, a piston plunger reciprocable in said cylinder and having a primary advancing area, a retracting area and a booster advancing area, and means to introduce fluid to each of said areas; a fluid displacement pump; a pressure manifold connected to receive fluid under pressure of said pump; a plurality of first valves connected respectively with said pressure manifold, the retracting areas of said motors, and the booster advancing areas of said motors and operable to selectively direct pressure fluid to either the retracting areas of said motors or the booster advancing areas thereof while connecting the other to exhaust; a plurality of second valves connected respectively with the retracting areas, of said motors and the primary advancing areas thereof to selectively direct pressure fluid introduced to the retracting areas simultaneously to the primary advancing areas or to connect said primary advancing areas to exhaust; means connected between said second valves and the primary advancing areas of said motors to vary the pressure of fluid passing therebetween; and check valves interposed between each of said first valves and said pressure manifold to prevent the passage of fluid in a direction from said first valves to said manifold.

In a hydraulic press control circuit; a hydraulic motor having primary advancing means, retracting means, and booster advancing means; a source or fluid pressure; a first valve means to direct fluid under pressure from said source to either said retracting means or said booster advancing means while connecting the other to exhaust; a second valve means connected between said first valve ineans and said retracting means to direct pressurefiuid to said primary advancing means simultaneously with the introduction of fluid pressure to said retracting means; and a check valve connected between said source and said first valve means to prevent the passage of fluid in a direction from said first valve means toward said source.

'4. A control circuit for a multiple station hydraulic press system, comprising a plurality of fluid-pressure-actuated motors each embodying a cylinder, a piston plunger reciprocable in said cylinder and having a primary advancing area, a smaller booster advancing area and a retracting area, and means to introduce fluid to each of said areas; a fluid displacement pump; a pressure manifold connected to receive fluid under pressure of said pump; a plurality of distributing valves each having a fluid inlet connected with said pressure manifold, a fluid outlet connected to exhaust, a first motor port connected with the retracting area of said motors, and a second motor port connected with the booster advancing area of said motors, said distributing valves being operable to selectively direct pressure fluid to either the retracting areas of said motors or the booster advancing areas thereof while connecting the other to exhaust; a plurality of second valves connected between the primary advancing areas of said motors and the first motor ports of said distributing valves to selectively direct pressure fluid discharged through the first motor ports of said distributing valves to the primary advancing areas of said motors simultaneously with the introduction of pressure fluid to the retracting areas thereof or to connect the primary advancing areas of said motors to exhaust; means connected between each of said second valves and the primary advancing areas of said motors to vary the pressure of fluid passing between said second valves and the primary advancing areas of said motors; and a check valve connected between each of said distributing valves and said pressure manifold to prevent the flow of fluid in a direction from said distributing valves toward said pressure manifold.

5. In a hydraulic control circuit; a hydraulic ram having a primary ram-advancing pressure area, a ram-retracting pressure area, and a booster ram-advancing pressure area; a fluid displacement pump; a first valve having connections with said pump, the ram-retracting pressure area Of said ram and the booster ram-advancing area of said ram, and operable selectively to introduce fluid under pressure from said pump to either the ram-retracting pressure area or the booster ram-advancing area while connecting the other area to exhaust; a second valve having connections with the ram-retracting area of said ram, the primary ram-advancing pressure area thereof and exhaust, and selectively operable to hydraulically connect the ram-retracting pressure area with the primary ram-advancing pressure area or to connect the primary ram-advancing area with exhaust; and a check valve connected between said pump and said first valve to prevent passage of fluid in a direction from said first valve toward said pump.

GEORGE M. GEIGER. PHILIP J. LINDNER.

(References on following page) The following x aferences are, of record in the file of this patent:

UNITED STATES PATENTS mama Dinzl ,2, 19 0 Nu ber n r'n i i at alnab-"2;; 194. liarrin tqn QQQ- 22 17:17:17.7"Ef? FOREIGN PATENTS Country Date Great Britain Apr. 10 L919