US2267508A - Hydraulic press - Google Patents

Description

J. P. sPENGLER v2,267,508

Dec. 23,` 1941.

I HYDRAULIC PRES S Filed Jun@ 5, 1959 ZZ H nu" Y .3

UNiTED STATES PATENT OFFICE HYDRAULIC rimss Johann vPeter Spengler, Berlin, Germany Appueeuen June 5,1939, serial No.y 211,525

In Germany October 2, 1935 l '4 claims. The invention relates to a hydraulic press with a reciprocating filling slide provided upon' the press table for lling the moulds and to the op..

eration thereof for the production of shaped bodies from ceramic masses.

It is characteristic of the operation of the hydraulic press according to the invention that the filling slide is employed as the sole control member in that, solely by the motion of the filling slide,.pressure water is first supplied to the upper .piston and that after a certain pressure has been reached the lower piston is operated by means of an intermediate valve and a piston acting as an accumulator. After removal of the pressure in the upper stamp the pressure water from the accumulator lifts up the lower stamp. 'This process can however not begin until after a maximum pressing effect has been produced. The pressed body however at rst still remains clamped fast between the upper and lower stamps and indeed until the moment where the upper piston is lifted up, whereupon removal of the pressed body then immediately takes place.

The upper piston is preferably a double piston and consists for example of a smaller piston and integral with this the actual pressing piston.

lThe pressure liquid rst acts upon the piston of smaller cross-sectional area, whereupon the pressure liquid, when the double piston has first travelled a certain distance, comes into action upon the surface of the actual pressing piston. As it sinks the pressing piston sucks in iilling liquid after it into the pressing cylinderthrough a feed conduit provided with a suction valve.

` Inone embodiment of the apparatus, the small piston is provided with a bore and a suction valve is connected to the pressing cylinder for sucking in iillingwater. v a short path has been travelled, a valve is automatically opened in the bore of the smaller piston so that the pressure liquid now passes through the bore of the smaller piston into the pressing cylinder and acts upon the surface of the larger piston, whereby the suction valve of the filling liquid feed conduit is'closed. During the actual pressing operationpressure l.liquid from the upper piston is at the same time stored up and this stored pressure liquid is employed to produce -a pressure upon the lower stamp forexpulsion. T he apparatus is so constructed that the expulsion pressure begins to act already during the main pressing operation, however the exy vpulsion of the shaped body cannot take place until the desired adjustable maximum pressure has been' attained. This arrangement ensures `that entirely uniformly pressed` shaped bodies are produced with the press.

For this purpose a pressure accumulator for the pressure waterv from the upper piston is ,connected between the pressing cylinder and the cylinder of the expulsion piston; this pressure accumulator incorporates 'a pressure valve which is adjustable according t0 the desired pressure for the pressing operation and the'valve chamber of 'which is connected with a piston under load.V A tube conduit forms the connection with the expulsion piston so that already during the actual pressing operation the expulsion piston is ready for the lifting. Hence only a small accumulator is necessary.

The to and fro motion of the fillingslide arranged upon the press table for the press moulds controls the pressing valve and the expulsion valve, and the press stamp is pressed into the press mould and thereby the preliminary pressing, rie-aeration, complete pressing and expulsion operations are effected. For this purpose a conduit leads from the pressing valve to the space Upon downward motion, after above the bore of the piston of smaller crosssection which is positively connected to the pressing piston. Moreover a conduit leads to the pressure accumulator incorporating the pressure regulating valve to which the cylinder of the loaded pressure piston is connected, from whence a Vconduit leadsv to the expulsion piston and the expulsion valve. The pressure piston is so" strongly loaded by means of a spring or the likeI that it yields a higher pressure than is necessary for the expulsion of the pressed body.

' Earlier hydraulic presses are indeed already known in which the expulsion also effected automatically with the aid of the filling box. In the earlier press however the lling box is not the sole and not the initiating or control member. In the earlier apparatus it is a matter of an entirelyv automatic operation which is initiated by the main pressure valve. With `the latter, adaptation to varying circumstances is not possible. According t6 the invention onthe other hand, and having regardr to this fact, the hydraulic press is semi-automatically operated.

The construction .thereof is quite particularly simple and the press, in' spite of. its manual operation, has the `sarne performance as a completely automatic hydraulic press. This is achieved because the operator hasvonly a. single movement to carry out, consisting of slidingthe filling box to and fro, which makes possible a 'rapidity of operation such as cannot be obtained when operating two control parts.

vented.

paratus is so constructed that expulsion can.

never take place until after the maximum adjusted pressure has been reached and that the shaped body is clamped fast between the upper and lower stamp until the moment where it can be removed after lifting of the upper piston. Thus any distortion of the pressed piece after the maximum pressure has ceased is avoided, so that also thin-walled ceramic bodies, Wall plates, floor plates, can be produced in a wholly plane form and damage to the shaped bodies is pre- An embodiment ofthe invention will now be described by way of illustration with reference to the accompanying drawing, in which Fig.l 1 shows a vertical section taken on the line I-I of Fig. 2 through a hydraulic press according to,and for carrying out the process of, the invention,

Fig. 2 is a section on the line II-II of Fig. 1, and

Fig. 3 is a section on the line III-III of Fig. 2. Referring to the drawing, the lling slide a with the drivers b, c and b1, c1 slides upon the press table in the channeled guide members d. The drivers b, c and b1, c1 control the pressing vvalve e and the expulsion valve f as the filling slide a slides backwards and forwards.

The pressing valve e is connected through a tube conduit g with a cylinder for the small portion of unitary pistoni, l1. This cylinder is provided with a bore in which an automatically controlled valve k is seated. The bore of piston z' opens at i1 into the pressing cylinder l to which a suction valve m is connected. The cylinder j is connected through the tube conduit n with the pressure-regulating valve o which can be regulated by means of the spring p or the like. The valve chamber of the pressure valve ois connected with the regulable pressure piston q inthe cylinder q1. The Vpiston is strongly loaded by means of a spring or by lever pressure, so that a higher pressure is exerted than is necessary for the expulsion of the pressed body. The pressure piston q is connected through the tube conduit r with the expulsion piston s and the expulsion valve f. The pressure liquid flows in in the direction of the arrow t, the exhaust water is led off in the direction of the arrow u and the suction valve m during the downward motion of the piston i sucks the filling liquid into the pressing cylinder l in the direction of the arrow v.

`In Fig. 2 the control by means of the lling slide a with the drivers b, c and b1, ci is shown as well as the valve arrangement for. the pressing valve e and the expulsion valve f. The valves e and f are movable upwardly and downwardly and are constructed as screw-threaded pins. They are arranged to be under the' pressure of springs h1, h2 as shown in Fig. 3 and have at the upper end a head t1, upon which the drivers b and c act and produce alterations in position.

The drivers c andci are in the form of wedges Aof hard' rubber or -some other resilient material,

and engage frictionally with the valve heads t1 which are `milled, corrugated or roughened at their periphery. Moreover an annular member carrying a lug is rigidly mounted upon the valve spindles e and f. A tension spring h engages. with each of these lug's and is secured at its other end to a rigid part of the housing of the valves e or f.

Upon pushing the filling box forward the driver c rotates the head ti and thus moves the valve spindle e into the closed position. At the same time the spring h. is tensioned. When the filling box a is withdrawn the driver c moves out of engagement with the valve head t1 and the spring h rotates the valve spindle e back into the starting position.

Instead of frictional drive with a tension spring, a lever control, eccentric drive, cam control 'or the like connected to the filling box a may be employed for operation of the spindles e and f.

The manner of operation of the hydraulic press is as follows:

The' filling slide a is pushed forward in the v guides d for filling the pressing mould and when filling has been accomplished is withdrawn beyond the zero position. During the latter operation the driver b, c closes the pressing valve e. The pressure water flowing in at t can no longer flow away unhindered in the direction of the arrow u but enters through the tube conduit g into the cylinder 7' of the small pistoni of unitary piston i-li and presses it-the Valve 7c being closed-downwardly until the valve is opened by the striking of member w at the end of the valve guide rod. Opening of the valve Ic takes place when the upper press stamp li has already penetrated into the pressing mould and the compression of the material to be pressed takes place, that is when the lost motion has been overcome.

The pressing piston l1 has necessarily accompanied the pistoni in its accelerated motion and has thus sucked in filling water through the suction valve m into the pressing cylinder l. The pressure liquid now ows through the opened valve k into the pressing cylinder Z through port il, closes the suction valve m and presses the pressing piston l1' with its upper pressing piston z' into the pressing mould. By means of the periodic motion of the filling slide the preliminary pressing, de-aeraton and main pressing operations and also the expulsion are effected. The pressure valve o does not open automatically until the prescribed maximum pressure has been Ireached; this valve can be regulated according' to the pressing pressure and stores up the pressure liquid necessary for the expulsion in the cylinder of the pressure piston q. The pressure piston q is directly connected through the tube conduit r with `the expulsion piston s. In this position the press is under high pressure but the expulsion pressure soon works itself out. By means of a small forward movement of the filling slide a, the pressing valve e is opened, the entry of pressure liquid t is interrupted and the liquid flows out in the direction of the arrow u and the pressure process in the pressing cylinder l is finished. At the same moment the pressure liquid collected at q closes the valve o and, through the tube conduit r, presses the expulsion piston s upward and lifts the pressed body from out of the pressing shape. The pressed body remains shut 2,267,508 v defining cylinder l and the platey which is attached` to piston l1. Springs :c and w1 are arranged to normally tend to retract unitary piston i-Zi to starting position. The pressure liquid in the pressing cylinder l lifts up the valve Ic and passes through the opening in the piston i,

throughv the tube conduit g and the opened pressing valve e into the water container at u.

lower piston for exhausting water from saidA In this position the expelled plate lies upon the lower stamp at the height ofthe press mould.I

The filling slide a is now moved over the press mouldfor the second nlling operationl During this movement the driver b1, crpushes-the expulsion valve f open.' Water exhausts ,from the expulsion piston s which falls back into itsorig'- inal position by its own weight or is brought backu into this position in known manner mechanically or hydraulically, the filling slide pushes the pressed plate away from the lpress table andl at the samel time places the material to be pressed as a.repeat lling in the press mould.`v

lower piston and to cause saidl lower piston to sink, and a second driver upon said slide arranged to open and close said exhaust valve upon motion oi said slide.`

3.' A hydraulic `press comprising a main 'upper piston and a lower piston, an auxiliary upper piston integral with said main upper piston, a

' filling slide for introducing a ceramic mass `,be-

tween said upper and lower pistons for compression therebetween' into a pressed body, means contr'oued by the motion of said siide for supply- Whilst the filling slide a is being withdrawn the second pressing operation commences. A motion may be applied positively to the filling slide beneath the silo for the purpose of distributing the material uniformly in the filling slide.

What I claim is:

1. A hydraulic press comprising an upper piston' and a lower piston, a lling slide for introducing Ja ceramic mass between said upper and lo'ver pistons for compressiontlierebetween into a'pressed body, means controlled by the motion of said slide for supplying pressure water to said upper piston to cause it to move downwardly to compress said ceramic mass, a pressure accumulator, an exhaust conduit leading from said upper piston to said lower piston through said pressure accumulator, a pressure regulating nonreturn valve in said exhaust conduitintermediate said upper piston and said pressure accumulator, said valve being arranged to open when said upper piston has completed its downward motion so as to allow pressure water to pass to and lift up said lowerpiston whilst said pressedA body is held fast between said upper and lower pistons.

2. A hydraulic' press comprisingan upper pis- ,ton and a lower piston, a iilling slide for introducing a ceramic mass between said upper and lower pistons for compression therebetween into Aa pressed body,a pressure water conduit for supplying pressure water to said upper piston to cause it to move downwardly to compress said ceramic mass, a valve in said pressure water conduit, a driver upon said slide, arranged to duit leading from said upper piston to said lower piston through said pressure accumulator, a

I pressure regulating `non-return valve in said exhaust conduit intermediate said upper piston and said pressure accumulator, said valve being arranged to open when saidupper piston has compieted its downward motion so as *to allow pressure water to pass to and lift up said. lower pis- 'ton whilst said pressed body is held fast between said upper andlower pistons, an exhaust valve connected to said exhaust conduit adjacent vsaid ing water to said auxiliary piston to cause it to move downwardly -together with said main upper piston, a bore through said auxiliary upper piston, a valve in said bore arranged to open when said auxiliary piston has travelled-a predetermined downward distance and to admit water through said bore to said main upper piston to cause itto move downwardly to compress said ceramic mass, a pressure accumulator, anexhaust conduit leading from said main upper piston to said lower piston through said pressure accumulator, a pressure regulating non-return valve insaid exhaust conduit intermediate said main upper piston and said pressure accumulator, said valve being arranged to open 'with said main upper ypiston has completed its down-` ward motion so as to allow pressure water to pass to and lift up said lower piston whilst said pressed body is held fast between said upper and lower pistons.

4. vA hydraulic press comprising a main upper piston and a lower piston, an auxiliary upper piston integral with said main upper piston, a lling slide for introducing a ceramic mass between 'said upperand lower pistons for compression4 therebetween into a pressed body, a pressure water conduit for supplying pressure water to said auxiliary upper pistoni to cause it to move downwardly together with said main upper piston, a valve in said pressure water conduit, a

.driver upon -said slide, arranged to open and close said valve upon motion of said slide, a bore through said auxiliary upper piston, a valve in said bore arranged to open when said auxiliary piston has travelled a predetermined downward distance and to admit water through said bore n' open and close said valve upon motion of said s slide, a pressure accumulator, an exhaust conto said main upper piston tocause it' to move downwardly to compress said ceramic mass, a pressure accumulator, an "exhaust conduit leading from said main upper piston to said lower` piston through said pressure accumulator, a pressurey regulating non-retum valve in said exhaust conduit intermediate said main upper piston and said pressure accumulator, said valve being arranged to open when said main upper piston has completed its downward motion so as to allow pressure 'water to pass to and liit up said lower piston whilst said pressed body is held fast between said upper and lower pistons, an exhaust valve connected to said exhaust conduit adjacent said lower piston for exhausting water from said lower piston and to cause said-lower piston to sink, and a second driverupon said. slide arranged to open and close said exhaustv valve upon motion of said slide.

JOHANN PETER SPENGLEB..

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