US2351317A - Hydraulic press system - Google Patents

Description

June 13, 1944.

HYDRAULIC PRESS SYSTEM Filed Aug. 17. 1942 2 Sheets-Sheet l INVENTOR: lazlzs/Ifmlremia,

ATTORNEYS.

L. A. cAMERoTA 2,351,317

June 13, 1944. L. A. CAMEROTA 2,351,317

HYDRAULIC PRESS SYSTEM File'd Aug. 17, 1942 2 Sheets-Sheet 2 INVENTOR: laws/I- (wile/via,

l 8a BY W W J ATTORNEYS.

Patented June 13, 1944 "HYDRAULIC PRESS SYSTEM Louis A. Camerota, Burlington, N. .I.,:assignor to Florence Pipe Foundry & Machine Company, Florence, N. J., a corporation of New Jersey Application August 1'7, 1942, Serial No. 455,057

3 Claims. (01. 121-38) eration or actuation. In such systems, however,

one disadvantageous condition prevails, which is mainly due to the fact that the'pressure/from the pilot-valve, acts 'onthe main-valve almost instantaneously, with the result a sudden rush" oi" high-pressure fluid through the pipes "leading to the press, or other machine, takes place with incidental destructive shock. The same rush action occurringwhen the press, or other machine, is reversed, but with greater violence and damaging effect, because the'fluidis trapped under high-pressure in thepress cylinder, whereby said cylinder and'th'e associated parts-are injuriously stretched and expanded. Furthermore, should the mainexhaust-valve beopened quickly, which is unavoidable in conventional systems, the pressure-fluid cannonades through the exhaust, because the pipe-line and valve'areas must be large enough to permit -said fluid to 'pass to discharge at high velocity, when at low-pressure.

The fundamental aim of this invention is to overcome the noted disadvantages, in a simple and effective manner, by providing a system and control therefor, whereby a press, or similarly actuated'machine, can be operated by fluid-under high-pressure without damaging shock either when starting or "reversing, regardless of how fast or slow the attendant may shift the operatinglever.

Another aim of this invention is the provision of an hydraulic press system, including in-flow shock preventing means and exhaust damping" means; said system being well adapted to the fabrication of shells "for projectiles, and containers for explosives.

Further aims, with ancillary advantages, of this invention "will-appear, as the nature thereof is better understood, from the following description of the typified embodiment illustrated by the accompanying two sheets of drawings, wherein like reference characters are used to designate corresponding partsin both views; while thefeatures of novelty are more particularly defined in the concluding claims.

In'the drawings:

Fig. 1 is a general and somewhat diagrammatic view of a hydraulic press system in accordance with, and including, the .novel features of this mvent'ion; said view illustrating the various valves and cooperative devices during themoving-up or opening cycle of the press; and I Fig. 2 is a similar view 'but showing the valves and cooperative devices in the position they occupy during the moving-down or active cycle of the press.

In describing the typified form of the invention, exemplified "by "the above captioned Views, specific terms will be employed 'for the sake of clarity, but it is to :be understood the scope of said invention is not thereby limited; each such term being intended to embrace .all reasonable equivalents which perform the same function for an analogous purpose.

The hydraulic press shown'an'd generally designated 3, in'the drawings, is of conventional type including a stationary platen 4 and ace-active or relatively movable-platen? by :and between which platens the "work 6 is operated on. The movable-platen!) has downward or active" movement imparted thereto by means of a ram 1 op- .eratingin a main cylinderB; whereas said platen 5 is elevated through the mediumof pull-back pistons 9, operating in return-cylinders l6 and having the lower endsof 'the piston'rods ll secured thereto.

Fluid or water, under high-pressure, for oper ating the press -3 is supplied from any appropriate source, not shown, through a main conduit 12 to a stop-valv -l3, and from whichit flows, by way of a pipe M, to aligned inlet ports Hi in the pilot-valve Hi. This pilot-valve t6 has an operating lever 11, 'f-ulcrumed a1; 18 to asuitable support 19, and it is also operatively-coordinated to a link '20, in turn serviceable through conventional mechanisms 2! to lift, or-open small pressure valves 22, 22' when the, respectively, associated exhaust-valves 23, 23' are closed under the action of individual springs 24 incompression, and vice versa. 7

Referring now more particularlyto Fig. l which illustrates the parts in position to effect the opening cycle of the press-3 it will b observable that, with the operating lever H in the position shown, the pilot pressure valve 22 and exhaustvalve 23 are open; while the respectively associated valves 22 and 23" are closed. High-pressure fluid entering the pilot-valve [-6, by way of the stop-valve l3 and pipe I4, passes the inlet port [5, valve 22', duct I'B' over closed valve 23, through port Hi" into pipe-line 25 and thence to the throttle-valve '26, wherein the in-rush shock is repressed. Fromthe valve 26 the in- ,flow passes by way of a pipe 21 to the upper end of the main, or three-way, control 28 to thereby 3|, in turnhaving a pipe connection 32 into the A branch 30, of determinate pressure side of the main control 28, with a forked-branch 33 into the lower end of said control. '1 I 7 It will now be readily apparent that upon high pressure fluid being admitted as just set forth,

pipe- lines 25, 21, and 30, 32, 33. At the same time the high-pressure fluid in the press mainc'ylin der 8 is permitted to dischargeby way of a comparatively larger diameter pipe 34, with -'a relatively-smaller continuation 34, to a check-valve 35 and pipe-line 36; the latter communicating into the pilot-valve I6, by way of an apertuIeIG and from thence through an outlet 31 to exhaust, or wherever desired. The action just de scribed breaks the force of the pressureaccumu lated in the main cylinder 8 and, hence, no shock occurs because the valves 22,22, 23, 23, are made comparatively small. As soon as thepressure in the pipe-line 34' is reduced it correspondingly falls in a branch 38, that connects into the hydraulic-loaded or top portion of a check-valve 38, whereby the latter is released; whereupomthe spring 48 influencing said check valve 39 reacts to raise or lift its plunger 4 I, from the seat 42, thereby permittingfluid from the exhaust-line 43 of the control 28, to discharge by way of a throttle-valve 44'and pipe-line 45, through the check-valve 39 and a branch 46 into the pipe-line 36, aforesaid, as well as into a pipe 41 and another check -valve 48, wherein the flow is blocked.' The valve 48 has a connection 49, into the line .36, through which the blocked flow-passes to the small exhaust-valve unit 23 of thepilot-valve Hi, and a duct I6 to the pressure valve '22 in small or greatly reduced volume. uch action, forthwith, relieves the pressure previously acting on top of the ex-- haust-valve 50, of the control 28, whereupon high-pressure fluid, supplied by way of the axially-aligned portion of the forked-branch 33, causes said valve 58 to rise or open, and thereby permit forced-flow of the high-pressure fluid from the main cylinder 8 through pipe-line 34, hereinbefore referred. to, and a pipe line to the valve 50 to the control exhaust-line 52, in considerable volume. The constant-pressure acting on the pull-back, or return, cylinders I8 will thereupon function, to elevate the pistons 9, and cause upward-movement of the platen 5, whereby rapid discharge of the pressure fluid in the main or operating cylinder 8 .is effected, with a resultant high-speed opening-movement for the press 3 without any shocking of the associated D Turning now more particularly, to Fig. ,.2 which shows the parts in the position they assume to effect the closure cycle, of the press 3, or its active stroke, the operating lever i1 isfirst moved to the location illustrated in said figure. 'High-pressure fluid from the source. of supply now entering the system, from the supply line l2, passes through the stop-valve l3 and pipe M, as before :set out, to the inlet port 15, ofthe pilot-valve l6. Now, in view of the operating lever I! having previously, through the means 20 and 2|, opened or lifted the valves 22, 23' and closed or lowered the valves. 23, 22; it

V the plunger 23 will be forced down and the inrush of such admitted fluid is repressed in the l.

will be evident that the hydraulic, or other, high-pressure fluid flows.through the valve 22, duct IB over valve 23, through orifice |6 and pipe-line 36, to the valve 35, wherein the in-rush is again repressed. Some of such in-flow will however, be diverted or pass through the connection 49 and open check-valve 48, pipe-line 41, throttle 44 and line 43, to the top of the control exhaust-valve 50, and thereby close said valve 50 gradually. At the same time the exhaust-valve 23, of the pilot-valve It, being open, the fluidpressure previously acting on top of the control plunger 29 will be relieved and exhaust through pipe 21, throttle valve 26 pipe-line 25, port I6",

and past open valve 23 to the exhaust outlet 31.

- During the just described'action release of the exhaust-valve 50 will be temporarily arrested by the fluid pressureon its top, blocked-in by the check-valve 48, and closure of the hydraulicloaded valve 39 by in-coming high-pressure fluid from pipes 34', 38; whereas the valve 29 will be gradually elevated tothe open position, shown in Fig. 2, by high-pressure fluid conducted therebelow through the branch pipe 30, stopvalve- 3|, pipe connection 32, and axially-aligned part of forked-branch 33; or, in other words, it will be understood that the valve 50 closes, before the valve 29 opens, and vice versa. As a result of the just explained opening of the valve 28, there will now be free flow of fluid under high-pressure, and considerable volume, from the connection 32 by way of the control duct 28' and pipe-line 5| into pipe 34 for direct downward action on the press ram 1, in the cylinder 8, whereby the platen 5 will operate on the work 6 in a positive manner, without any shocking of the cylinder 8 and adjoining parts of the press 3.

Constant-pressure fluid is supplied to, and vented from the pull-back or press returncylinders I 0 by way of pipe connections 53 from a pipe line 54, in flow communication with a suitable source, not shown, in accordance with known practice.

Particular attentionis, herein, directed to the fact that, what might be termed the service- sum ply pipes 30, 34 and 5| in addition to the control exhaust line 52 are, preferably, made of determined larger diameter than the various other pipes I4, 25, 21, 32, 33, 36, 38, 43, 45, 46, 41 and 48, as well as the continuation 34', intervening the unionof the pipes 34, 5|, and the check-valve 35, to facilitate precision actuation of the press 3.

From the foregoing it will be readily seen that the press 3 cannot open unless the pressure in pipe- lines 34 and 5| is reduced, the same only being possible of attainment by joint use of the small valves 22, 22', 23, 23' in the pilot I6; the

7 line 34 with its relatively smaller continuation 34' to check-valve 35; and the corresponding small er pipe-line 36. It is, also, to be remarked that, the exhaust-valve 50 of the control 28 cannot open until the pressure is relieved from above the plungerv 4| of the hydraulic-loaded checkvalve 39-;and, furthermore, in view of the two just stated important factors, the pipes 34, and 5| will be correspondingly relieved of high-pressure, whereby the press 3 only opens gradually, or without destructive shock occurring, incidental to sudden release of the high-pressure.

From the foregoing it is thought the merits and advantages of this invention need no further elucidation herein; while it will be equally obvious that various changes in the details described may spirit and scope of said invention, as more concisely expressed in the following claims.

Having thus described my invention, I claim:

1. In systems operated by fiuid pressure for energizing a device productive of mechanical work, dual reciprocative means respectively designed to impart effective and inefiective movements to said device; a main control and pipe arrangement governing supply and venting of high-pressure fluid to and from the reciprocative means; associated stop, directive and check means in an inflow portion of the conduit arrangement, said directive means including relatively small pressureand-exhaust devices, and the check means serving to prevent in-flow shock to the main control; a branch from the supply side of the pipe arrangement aforesaid and stop means in circuit with the main control to impart eilective movements to the reciprocative means; and a loopsection in the pipe arrangement including a fluidpressure loaded check device with reactive means effective to damp exhaust flow from the reciprocative means during the ineffective movements of the latter, whereby the system is prevented from destructive operating shocks.

2. In a hydraulic press system the combination, with a movable-platen, of ram and piston means for respectively imparting active and return movements to said platen; a conduit system, including a main control-valve, governing supply and venting of high-pressure operating fluid, to and from the ram means; associated stop, pilot, and throttle valves in an in-flow portion of the conduit system to the top of the control-valve,

said pilot-valve including plural pressure-andexhaust units, all of which are of comparatively V small corresponding area, and the throttle-valve serving to repress the in-rush shock of the flow,- to the'main control valve conduit portion of the system; a branch from the high-pressure main supply line to the system, with an interposed, stop-valve, for concurrent in-fiow of high-pressure fluid to and through the control-valve to effect active movement of the ram and platen; an exhaust-line from the ram means, including acheck-valve, to the pilot-valve; a loop in the exhaust-line having connection thereinto to each side of the included check-valve, said loop includf ing a fluid-pressure loaded check-valve with reactive means effective to relieve pressure acting thereon from the control valve as the pressure in the exhaust line reduces; a branch line, from the top of the outlet side of the control-valve into the exhaust-line aforesaid having flow-connection to the pressure-loaded check-valve; and in--

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