US2615302A - Hydraulic press - Google Patents

Description

L. A. CAMERQTA HYDRAULIC PRESS O'ct. 28, 1952 Filed July 7, 1949 3S @l lNMvNLN y A TTORNE YS.

| A. CAMEROTA HYDRAULIC PRESS Oct. 28, 1952 8 Sheets-Sheet 2 Filed July 7, 1949 NN Y %\N mSN .@N QNN QE INVENTOR: Inl/1.5%. h1/MMM ATTORNEYS.

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Patented @et 28, 1952 anni l ltiYDRACULICv PRE S S Louis Amore Camerota, Burlington, N. J., assigner to Florence Pipe Foundry & Machine Company, Florence, N. J., a corporation of New Jersey Appiicationuly 7, 1949, Serial No. 103,507

This invention relates to hydraulic presses. More specifically, it is concerned withhydraulic ow of the pressure uid to the ram and lift cylinders isgoverned by solenoid actuated reversible valves, the solenoids being interposed in circuits controlled foy push buttons. In most such hydraulic presses as heretofore constructed, the speed of the ram plungers is constant through their active strokes, and accordingly, the approach of the plungers to the material being operated upon is attended by considerable impact, with consequent creation of objectionable noises and vibrations, as well as imposition of severe strains on the presses. Moreover, in hydraulic presses of the kind particubuttons are ordinarily utilized to control the presses for impartation of intermittent movements to the ram plungers when repairs or adjustments are to be made, or when dies are to be interchanged. Due tothe inability to properly govern ow or the pressure fluid in this way, it is impossible to accurately control the movements of the ram plungers.

The chief aim of my invention is to overcome the foregoing difficulties and drawbacks. This desideratum is realized in practice, as hereinafter more fully disclosed, through provision of simple and reliable automatic means whereby the movement of the ram plungers of the presses is decelerated as they near the end or their active strokes so that they will meet the material worked upon gently, with avoidance of noise and of sudden impact such as would be likely to overstrain the presses; and through the further provision, likewise, oi simple and reliable manually-operable means whereby the fiow of lpressure iiuid to and from the ram and lift cylinders can be governed to a nicety to effect smooth and accurate movements of the ram plungers and instant stoppage thereof at any desired point within the limits of their travel in either direction when necessary, for convenience of making repairs or adjustments, or incident to interchanging dies.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, whereinv Fig. l is a diagrammatic view of a press and a control system therefor conveniently embodying my invention, with the press shown in its normal open position.

Figs. 2 and 3 are views like Fig. 1 showing how the press is controlled during the active or descending stroke of the ram plunger.

Fig. 4 is a View like Fig. 1, showing the press closing under high pressure under manual control.

5 Claims. (Cl. 'dil-52) Fig. 5 is a similar View showing the press moving up under manual control.

Figs. 6 and l are views in turn likeFig. l, respectively showing the press moving down and up under manual control; and v Y Fig. 8 is a sectional view of a master valve used in the automatic control of the press.'

With more detailed reference to these illustrations, i@ designates the ram cylinderfoi the press, and H the ram plunger whereto is secured. the movable platen l2 which is opposed by the xed platen at i3 in compacting material M placed on the latter platen. The press is provided with ram .plunger lift cylinders I4 which are arranged on each side of the stationary platen i3 and which have their plungers l5 affixed to the movable 'platen l2. Ordinarily, the operation of the press is controlled from a panel l5 provided with cycle start and stop push buttons il, i8, which,

through means presently described, cause the press to he opened and closed. The buttons l'l and i8 are interposed in a wiring circuit(not illustrated) with solenoids 2i and 22 whichy are arranged to operate the pilotvalves '23" and 2li of a reversible four-Way master valve offwell known construction conventionally repre-sented at `25 in Fig. l and shown in greater detail irl-Fig. 8, having a portedplunger 26. The pilotvalves 23, 24 serve to admit oil or other actuating fluid, delivered at a relatively low pressure through piping 2, 28, 29, 36 by a pump 3|, into opposite ends of the casing of the master valveV 25. Normally the valve 25 is ventedv top4 and bottom through the Joy-pass ports indicated at 25a, 25h, respectively, with its plunger or piston heldin neutral position .by a spring 26a, as' hest'seen'in Fig. 8. The pressure of the pilot 'actuating fluid is indicated by a gauge 32 on the panel i6, said gauge being connected to the end of a branch pipe 33 which extends from the pipe sectionZ'l. The pump 3l, together witha driving motor 35 therefon-is mounted upon a supply tank 36 from which the uid is drawn. Connecting withlthe pipe section 21 is a pipe line Si, 33 which extends to the rear of tank 36, part of said line passing through a cooler 39. Flow through the pipe section 37 is restricted by 'a restraining valve 4i), and any lsolids passing throughthe section 38 are trapped by a strainer indicated at 4I. The devices represented at ft2 and 43 `are safety valves. Also mounted on the tank 36 is a pump 45 with a drive motor Q5, which delivers fluid at high pressure used to operate the ram I0 of the press on its power stroke, the ow of 5 this fluid being governed by the master valve 25 in a manner later on explained. Startingand stoppingof the pilot pressure and the high pressure pump motors 35 and 46 is effected by separate pairs of start and stop push buttons 41 and 48 on panel I6. As shown, a pipe line 49 with a safety valve 50 therein extends from the pump 45 to the port p1 of master valve 25, and a pipe line I, 5.2 from the port p3 of said valve to the top of the ram cylinder I0, the check valve at 53 permitting ow only in the direction indicated by the arrow thereon. A regulatable throttle valve 54 is provided to control flow through a shunting .by-pass 55 around the check valve 53. The pressure of the fluid is subject to the control of a pressure governor 56 mounted on the panel I6 and connected by a pipe line 51 to the bottom of ram cylinder I0. Leading from theport p2 of master valve 25 is a pipe line 53, 59, 60, 6I with branches 63 and 64, 65 connecting respectively into the bottoms of the lift cylinders I4 and into the actuating cylinder 66 of a lling check or relief valve 61 within a fluid tank. 68 abovethe ram cylinder I0. Check valves 69 and 10 in the pipe sections 59 and 64 permit flow only in the direction indicated b-y the arrows, in-iiowto the cylinder 8G of the lilling check valve 61 being regulatable by an adjustable throttle valve 1I, and outflow by a throttle valve 12 in ahy-pass 13 around said check valve 18. Excess fluid accumulating in the tank 68 overows, by Way of a pipe 15, into the storage tank 3-5. The rising movement of the platen I2 is terminated automatically through engagement of the tapered head 80 rat the top of a rod 8| carried by a. lateral bracket 82 on said platen, with. a limit switch 83 in circuit with the push buttons I1 and I8. The. rod 8| is threadedly engaged in the bracket 82 and, as shown, is adjustable through worm gearing 84 operable by a. hand wheel 85.

For the purpose of decelerating the ram plunger I I as it approaches the material M in its descentand thereby damping its impact with-the latter, there is provided in accordance with my invention, means including a special speed governing choke valve 86 with a circumferentially grooved piston 81 within its casing adapted to control flow between oppositely disposed ports p5, p6, p", said piston being subject to the inuence of a spring 88. Extending from the piston 81 through one end of the casing of valve 881s. a rod 89 with a roller thereon in the path of a tapered head 90 of another rod 9| pendent from a lateral. arm 92 of bracket 82 on the movable platen I2, said' rod being also adjustable up or down relative to. said platen. As shown, the port p5 of choke valve 86 is connected to the pipe 58 by a` branch 93. The port p6 of valve 8.6 is in turn connected by a branch, pipe 94 to the pipe 6.0, with interposition in the latter of a regulatable, throttle valve 95, and the port p." of said valve, 881s in communication, through. the pipe 59' by way of a branch 9B, with throttle and check valves, 91 and 98 respectively interposed therein.

In place` of theusual yjogging buttons for controlling intermittent movements of the pressduring interchange of dies, or while repairs or adiustments. are being made, there is further provdedin accordance with my invention, a special reversible.. auxiliary manually-operable reversible control valve |00 which is generally similar in construction to the master valve 25, butin which the ported piston IOI is operable by means of a hand lever indicated at |02. This special' valve |00 has ports p18, p9, p10, and p11. The port p10 is connected by a pipe branch |03., to the pipe 52; the port p9 by a pipe |04 to the port p4 of master valve 25; the port p8 by means of piping |06, |08 to the branch 94; and the port p11 by a pipe line |09 to the reservoir 68, above the ram cylinder I0. Interposed in the pipe |06 is a check valve IIO which permits flow in the direction indicated thereon by the arrow, and which is shunted by a loop I I I with an interposed regulatable throttle valve ||2. The pipe |08 is extended as at II3 to connect with pipe line |09, and interposed in this extension is a normally closed hand valve I I4. There is also a cross connection |I5 between the pipes 60 and |09 with a safety valve IIIv therein. The switch shown at I|1 is in circuit with the solenoid coils 2| and 22 of the master valve 25, and is arranged to be actuated by the hand lever |02 of the manual switch |00 for a purpose later on explained.

Normally with the solenoids 2| and 22 both de-energized andthe pilots 23 and 24 of master valve 25 closed, the piston of the manually operable valve |00 in neutral position, and the press open and dormant as in Fig. 1, the following conditions obtain: The pilot actuating fluid drawn from `the tank 36 by pump 3| is circulatedidly through the piping 21,V 31, 38y and the tank 3.6. Fluid at the same time delivered by the pump 45 at high pressure iiows through pipe 49v tothe port p1 of master valve 25 and vby-passes through the channeled piston 26 to port p4, thenrcontinues through pipe |04 to port p9 of valve |09 vand then ley-passes through the channeled piston HJI of the latter valve to the port p11. From thence vthe flowproceeds through pipe line.- I-0.9: and discharges into the reservoir 68 above theram cylrlder I0, wherefrom the overflow is conducted, by the pipe 15, back into the tank 3.6. The platen I2 is prevented from descending by reason of fluid trapped in the lift cylinders If4 and in the piping 58, 59, 6.0, 6I, 63,93 and 9.4. Safety valve |.I'9 serves merely as a means for preventing intensified pressure inthe line. When valves 25` and |00 are positioned asin Fig. l and valve, |:I'4 is closed, the fluid is trapped in the cylinders. |4.

Automatic cycle operation The platen I 2 is ordinarily lowered under'push button control, the cycle being initiated by energization of solenoid' 22 and opening ofthe lower pilot 2'4 of master valve 25 for admission of pressure iiuid from the pump 31|, via pipes 21, 28i and 30 as push button I1 is d'e-pressed', with consequent shifting of piston 28 of said valve upward to the position in which it is shown in Fig. 2'. As a consequence, exhausting of the lift cylinders I4 will take place through the pipes 63, 60, 94, valve 86, pipes 93, 58', master valve 25, pipe |04, valve |00 and pipe |09 to the reservoir 648.

As the ram plunger I-I begins to descend, the fill check valve61 opens automatically in response to suction, thereby allowing down flow of li-uid from the reservoir 88 into the ram cylinder I0. At the. same time, fluid is injected into the ram cylinder I 0 from the tank 35 by actionA of the pump 45 through pipe 49, master valve 25 (now set as above explained) and pipes 5|, 52. The platen I2 will thus descend rapidly until itl nears the material M, when, by contact ofthe camhead of rod 9| on said platen withv the actuating rod 89 of valve 89, the piston ofthe latter will be shifted to the position in which it is shown in Fig. 3.. Under these conditions the exhaust from the lift cylinders I 4- will be by-passed between the ports p6 and p7 ofV valve 85 enroute from pipe 60 to pipes 59, 58, and thus traverse the 5 throttle valve 91 in pipe 06, the -lattervalve thus determining the rate of descent of the ram pluner I| and platen I2. The lling check valve 61 will be closed by action of its spring upon cessation of the suction when the platen yI2 eventually contacts the material M as in-Fig. 4, whereupon pressure is built upto the required degree in the ram cylinder by the continued operation of pump 45. As the platen I2 continues in its descent, the cam head 90- of rod 0| will eventually Contact the rod 09 and thereby cause the piston 81 of valve 86 to be shifted rightward to the position in which it is shown in Fig. 3, with consequent closing of port p and establishment of communication between ports p5 and pl. The exhaust from the lift cylinders I will therefore take place now by lway of pipes 03, 00, 94, 90, throttle valve 91, check valve 90, pipes 50, 58 master valve 25, pipe |04 valve v|00 and pipe |00 to the reservoir 68. The ram plunger II will then move more slowly to the completion of its downward stroke to compress the material M. By regulating the throttle valve 91, it is possible to determine the rate of decelleration during the final portion of the down stroke of the ram plunger I In this way, it will be seen that contact of the platen I2 with the material M will be effectively damped, with avoidance of any attendant jar or noise or impartation of sudden harmful jars or strains to the press. maximum pressure predetermined by the governor 56 is reached, the latter functions through its electrical contacts (not illustrated) to cause deenergization of the solenoid 22 and energization of solenoid 2| and reversal of master valve 25, i. e. depression of the piston 26 of the latter as in Fig. 5, whereby the pressure in the ram cylinder I0 is slowly relieved to prevent shock in the pipe lines, said piston being shifted by the pilot pressure iiuid conducted into the top of said valve from the pump 3| through pipes 21, 28, and 29. By this reversal of master valve 25, high pressure fluid from pump 45 will flow by way of pipe 49 to said valve, by pass between the ports 101, p2, then continue through pipes 58, 50, 60, 63 to the lift cylinders I4 to elevate the ram plunger II. Under these conditions, exhaust from the ram cylinder I0 will take place at the same time through the by pass pipe 55 containing throttle valve 54, pipes 52, 5I, ports p3 and p4 of master valve 25, pipe |04, ports p9, p11 of valve |00, and pipe |00 to the reservoir 68. In this connection it will be noted that the throttle valve 54 prevents rapid release of a built up pressure in cylinder I0 and thus prevents line shock. The filling check valve 61 will be opened as in Fig. 5 to permit up-flow of fluid from the ram cylinder I0 into the reservoir B8 and more rapid rise of the ram |I, through actuation of its cylinder 00 as pressure builds up Within pipes 65 and 6|. When the head 90 of rod SI passes beyond the actuating rod of valve 86, the piston 81 of the latter will be thrust forward by the spring 88 to its original position for re-establishment of communication between the ports p5 and p6. Finally, upon actuation of the limit switch 83 as the ram plunger I| nears the end of its up stroke, the electric circuits will be broken and the master valve will resume its neutral inactive position for re..- toration of the parts to the condition of Fig. l. Valve 86 performs no useful function during the retraction or rising stroke of the ram plunger l I.

Manual control Control of the press incident to making re- When the in emergencies, is accomplished, in accordance with my invention, bymanual actuation of the special reversible valve |00.

valve |00 is depressed as in Fig. 6, with incidental tripping of the switch I I1. As a consequence, all power supply to the press is interrupted except to the pump motors 35 and 46, the pressure governor` 50 and the limit switch 83 being thereby rendered ineffective and the solenoids kept deenergized for maintenance of the master valve 25 in neutral position as also shown in Fig. 6. Under these conditions, high pressure fluid delivered by the pump 45 will flow by way of pipe 49 to port p1 of master valve 25, continue through the channeled piston 20 of the latter to port p4, then through pipe |04 to port p9 of valve |00, by pass to port p10, and finally, by way of pipes |03 and 52, into the top of the ram cylinder I0 to force the plunger downward. Exhaust of iluid from the lift cylinder I4 is allowed to take'place at the same time, the flow being by way of pipes 63, 60, |08, III, |00 communicating ports p8 and p11 of valve |00 and pipe |00 into the reservoir 08 above the ram cylinder I0. The rate of`descent of the ram being in this instance governed by the regulatable throttle valve |I2 in the pipe II|. The valve 86 will of course be actuated during the drop of the ram plunger I, but without accomplishing any useful function. By moving the operating lever |02 of the manual control valve |00 to horizontal position, the ram plunger |I may be stopped at any desired position in its descent.

When the ram plunger I I is to be elevated under manual control, the operating lever |02 of valve |00 is lifted as shown in Fig. 7, with the result that switch ||1 is actuated, as before, for

maintenance of master valve 25 in its normal position, within the piston I0| of said valve |00 lowered. Under the latter conditions, high pressure fluid delivered by pump 45 will flow through pipe 40 to port 'p1 of master valve 25, by pass to port p4 then flow through pipe |04 to port p9 of manual control'valve |00, by pass to port p8 into pipe |06, from whence the flow continues through pipes |08, 60 and 03 into the lift cylinders |4 to elevate the ram I At the same time, part of the liquid will iiow by way of pipes 0I, 64, and 65 to the then open lill check valve 61 and permit upward discharge from the ram cylinder I0 into the reservoir 68.

From the foregoing it will be seen that the manual valve |00 can be used at will by the pressattendant to control movement of the press in either direction regardless of the position of the ram and the platen, and during any stage of the operating cycle of the press.

Having thus described my invention, I claim:

1. A control system for a hydraulic press having a ram cylinder, a fixed platen opposed by the plunger of the ram cylinder, a vlift cylinder for raising the plunger of the ram cylinder after each press operation, a supply source of pressure fluid and piping connecting the ram cylinder and the lift cylinder with the supply source; said control system including a power-actuated master valve having a bore and a piston therein which, when rshifted. in one direction from a normal neutral position permits delivery of pressure fluid to the ram cylinder to close the press, and when shifted in the other direction permitsdelivery of pressure uid to the lift cylinder for opening the press, and having incorporated selectively-operable mag- Forthe loweringv of the ram plunger II, the hand lever |02 ofv vnetically-actuated pilot valves for admitting pressure fluid from another supply source to admit pressure fluid into opposite ends respectively of the bore to shift the piston in vone direction or the other as aforesaid, and a manually-operable auxiliary Valve interposed in the piping in serial relation with the master valve and having Va piston with means whereby the latter can be shifted from a neutralposition in one Adirection or the other while the master valve is maintained in neutral position, to permit delivery of pressure fluid to the ram cylinder for closing oi the press, or admitting pressure fluid into the lift cylinder for opening of the press.

2. A control system for a hydraulic press according to claim 1, further including automatic means for throttling exhaust of fluid from the lift cylinder as the plunger of the ram cylinder nears the end of its compressing stroke under the inuence of the pressure fluid during press closing.

3. A control system for a hydraulic press, according to claim 1, further including exhaust piping through which the lift cylinder exhausts freely by way of the master valve during the greater portion of the active stroke of the ram plunger, a choke valve interposed in said exhaust piping, and means on the plunger of the ram cylinder for actuating the choke valve as said plunger nears the end of its active stroke to restrict the exhaust ow from said lift cylinder and thereby retard the ram plunger While it completes its active stroke.

4. A -co-ntrol system for a hydraulic press, according to claim 1, further including ya check valve interposed in the piping between the ram cylinder and the master v-alve and adapted to close during exhausting of said cylinder, a bypass around said check valve, and a throttle valve in said by-pass for throttling the exhaust flow from the ram cylinder to determine the speed of the ram plunger during its return stroke.r

trolling flow of the fluid between theram cylinder and the tank, means automatically operated to open the relief valve, and keep it open for upward passage of uid from the ram cylinder during the greater portion vof -the rise of the ram plunger, means automatically Aoperated as the ram plunger ne-ars the limit of its upward stroke to close Said relief value, va check valve interposed in the piping between the ram cylinder and the master valve and ad-apted to close vduring exhausting of said cylinder, a by-pass around the check valve, and a throttle valve in said Aby-pass for throttling the'iiow from the ram cylinder to retard the movement of the ram plunger after closing of the relief valve while said plunger com pletes its return stroke. l

LOUIS AMORE CAMEROTA.

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

UNITED STATES PATENTS Camerota June 21,1949

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