US1753742A - Hydraulic press - Google Patents

Description

April 8, 1930. J. DE FRANCISCI HYDRAULIC PRESS 2 Shets-Sheet 1 Filed July 9, 1926 QvwzQtQ'c' UbSG/ZFZ 261 7 2100 j agi bwmrm p P 1930- J. DE FRANCISCI 1 ,753,742

HYDRAULIC PRES 5 Filed July 9, 1926 2 Sheets-Sheet 2 INVENTOR 'ATTORNEY I Patented Apr. 8, 1930 '7 earner ori ice DE FBANCISCI, 0F BB GOKLZN, NEVT YORK V retrial-metro Application mes m 9, 1926i Serial No. 121,220.

a material compacting mechanism e o-operto reversing the material cylinder able with the material cylinder of the press for the purpose of applying pressure to the material contained within said cylinder whereby such material is forcibly compressed with a View to increasingthe density of the mass. V

One object of the invention is to apply pressure to the mass of material, and to continue the application of such pressure for a determined period, with a view to precluding expansion of the mass of material the period which elapses between the initial condensation of the mass and the application pressure to such mass by the operation or" the extruding plunger or ram constituting an element of the hydraulic motor, the latter be} ing an element of the press.

A further obj ectis 'the control of the a; ing mechanism, the same being dependent in a measure upon the movement of the extruding plunger orrain, which packing mechanism is initially started into operation by the movement oi'a manually actuated mem her with a View to effecting the power stroke of the packing plunger. Thereafter, the packing mechanism isjset inte action on the upward travel of the extruding ger or ram to the end thatthe packing pli. s is withdrawnby i'luidpre'ssure from the material cylinder, whereby the paclzi mechanism is restored to normal pcsi ion charging position to a service position.

I Broadly. stated, my invention is a hyc packing mechanism associated with a p and with reversible in'ateriahcarr ing' cylinders, whereby on the upstroke of the e;-

. of macaroni, said press being 01 the tyne dislever, such as e, and associated witha truding plunger .or ram the-pac Hg drawal from the material cylinder of the paclnngpiunger."

Other functions and advantages of the invention will appear from the following description taken in connection with the drawings, wherein Figure 1 is a side elevation of my packin' mechanism associated with a hvdre the extruding plunger and l p plunger being shown in their i oimal raised positions. 7 Q l Figure 2 is a longitudinal sectional view through the control valve for said packing mechanism.

Figures 3, 4i and 5 are views partly in tion and partly inelevation oi thvalve and a valved by-pass in the d. positions which said valve the pass assume on the up and down travel of the truding plunger or ram; l

Figure ,6 illustrates views in side and end elevation respectively of the rotary men l of said control valve of the packing mechanism. In Figure 1 there is shown generally 1 I P h draulic press adapted for the inanuracture C L] closed in'my i atent No. 1,502.02 in Said Figure 1 there is shown a hydraulic motor including a power cylinder, A, and an Oltrudin ram or'plunger, B, a plurality of i in reconnected material cylinderaflC, C, versible relation to'the plunger or 1 extruding die, D, supported by a Carrie D and a master valve,'E, operated by a hen pipe, fiend a return i e, 7, together other pipes, 5/, 9, leading from the master valve,'E, to the power cylinder A, said pipes g, g, leading amotive fluid between JllS valve and the top and bottom parts ofsaid power cylinder. The several mec anisms con.- structed and operated as disclosed by my aforesaid patent, and do not require further lUll der, 0, C.

To the packing cylinder G are connected pipes h, h, leading from a control valve I forming an element of the packing mechanism, one of said pipes as it being attached to the upper head ofthe packing cylinder G, whereas the other pipe h is attached to the lower part of said packing cylinder.

The control valve I of the packing mechanism is shown more particularly in Figures 2 and 6, whereas the relation of said control valve to the bypass is illustrated in Figures 3 and 5, inclusive. As shown, the valve I comprises a shell, 2', and a plug rotatably seated within the shell, said plug embodying a frusto-conical body portion, 7', and a cylindrical stem, j. The valve shell 2' is provided interiorly thereof with a chamber r; forming conical seat, and with a longitudinal axial bore for the reception, respectively, of the conical body j and the stem j, whereby the valve plug is seated for rotative movement within the shell 71. The stem 9" of the valve extends through one end of the shell, said protruding end of the stem having a squared portion y' and a threaded portion, j see Figures 2 and 6, and on the threaded portion is screwed a nut operating to compress a spring is for the purpose of exerting pressure on the Valve plug for drawing the conical body portion j snugly to its seat provided by the conical part of chamber 7?, within the valve shell, see Figure 2. The valve shell is provided with suitable means for the attachment of the pipes required for the flow of the motive fluid, and in addition thereto the valve shell is provided with a return chamber m for the motive fluid, which chamber m surrounds the valve stem j, see Figure 2. The conical part of the rotary valve occupies a part only of the chamber n, one part of which chamber is taken up by the conical valve seat, but to- Ward the end of the valve shell, this chamber V ure 0, made to fit tightly by a packing 0' to preclude leakage of the motive fluid; said plug 0 being in facing relatlon to the end face of the valve plug j, and being spaced with respect thereto so as to leave a space or subchamber indicated at 12, through which is adapted to flow the motive fluid from the source of supply. 7

The rotary valve plug is provided in its conical portion with a series of feed channels or grooves 29, g, 1, which extend to, and open through, the end face of the conical body j, see Figure 6. In addition to these feed channels, the conical part of the valve'is provided .valve body, and they open into a common return passage '0 provided axially within the valve body and the stem j thereof, said common return passage having a port 11 which opens into and communicates with the return chamber provided within the valve. shell, See Figure 2. I

Motive fluid from a source of supply, such as a pump or accumulator, is conveyed to the control valve by a pipe H, one end of which is attached to the valve shell to feed the fluid through a port it, with which is adapted to register one of the feed channels p or 9, according to the positionoccupied by the valve plug within the valve shell, whereby the fluid under pressure flows from pipe H, through port k one of the channels per g, to the subchamber n,and through this chamber a to one or the other of the pipes h or h, whereby fluid under pressure may flow to the upper part or the lower part of the packing cylinder G for the actuation of the packing plunger by the energy of said motive fluid.

A return pipe H" for directing the flow of motive fluid from the valve back to the pump or accumulator is connected to the shell 2' for communication with return chamber m, and to this chamber 122, and pipe H flows the motive fluid from one end to the other of the whereby fluid under pressure is admitted to one cylinder end, whereas fluid from the other end of the cylinder flows out of the same under the travel of the packing plunger.

The return passages, s, t, u, are formed in the valve body in the same plane, see Figure 6, and the feed pipe H and flow pipe h, h, are attached to thevalve casing in the same plane, in which are positioned the return passages aforesaid. The longitudinal return passage 1) within the valve extends from ports which open into the chamber m to the return passages s, t, u, so as toserve as a common return from either end of the packingcylinder, to the chamber m and thence to the single return pipe H. This longitudinal return passageo does not open through the face at either end of the valve, but for manufacturing purposes in boring the return passage 1) it is bored through the end face at the enlarged conical part j of the valve, and there motive fluid from master valve E flowing by pipe 9 to the lowerpart of the power cylinder A in effecting the up movement of the plunger or ram B. At a desired period in the upward movementof ram B, the control valve I is reversed automatically as will hereafter appear, to depress the arm J to the downwardly inclined position of Figure 4, which reversal of the valve changes the plug from the position of Figure 5 tothat of Figure 4,

and which reversal shifts the passages g, 1",-

out of register with pipes H, h, and return passage u out of register with pipe h, whereby such reversal from Figure 5 to Figure 4: brings the passage p into register with feed pipe H, and the passage r into register with pipe it, whereas return passage 25 registers with pipe it. As a result of such valve reversal, the motive fluid is supplied to the lower part of packing cylinder G, and the fluid present into the upper of said cylinder G is displaced by the upward travel of the packing plunger, the infiowing motive fluid passing through pipe H, port if, thenceby passage p to chamber a, thence by passage 1* to pipe h to the lower part of cylinder G for raising the plunger G, G but the liquid displaced by such upward movement of plunger G, G flows out of the upper part of the cylinder by way of pipe h, passage t, to longitudinal passage o, chamber m, and by pipe H back to the pump.

The liquid from the pump to the control valve I flows substantially constantly through the valve I the enlarged conical body of which valve is exposed to the pressure of the liquid flowing through chamber at. The valve is thus held by liquid pressure to its seat, aided in a measure by the action of spring 7c, and when the valve is rocked to the position of Figure 5 for feeding liquid to the upper part of packing cylinder G, and to effect the down travel of the plunger G, G the pressure of such liquid in chamber n against the end face of the conical valve part j acts to retain the valve in said position against the ponderosityofthe weight K acting on the valve arm J, to the end that said valve plug will remain in the position of Figure 5 during the downward movement of packing plunger G", G and while such packing plunger in said lowered position within the material cylinder and during a part of the upward travel of the extruding plunger or ram B. There comes a time, however, in the upward travel of plunger B at which the pressure of the fluid in chamber a," and upon the end face of valve body j is relieved, for a brief period, whereby the valve plug is adapted to. be turned automatically by the ponderosity of the weight K acting on the arm J, so as to automatically 7 reverse the valve I from the position of Figure 5, to the position of Figure 4. 1' v This relief to the fluid pressure on the end face of valve I is obtained by a by-pass,

shown more particularly in Figures 8, 4; and 5, wherein L is a pipe coupled to the valve shell 2'. for communication at all times with the valve chamber a, see dotted lines in Figure 2, and'indicated also in Figures 3 to 5. Thispipe L is attached to the upper part of the casing or shellM of a relief valve, the lower part of saidvalve casing M being connected to a pipe L, the other end of which pipe L is attached to the power cylinder A at the lower part thereof, see Figure 1. The interior of the valve casing M is divided by a wall to to produce an upper valve chamber it and a lower piston chamber y, and in the wall itself is formed a longitudinal passage 2 and a transverse port 2. lVithin the valve casing M is a triple valve con'iprising a rcciprocating member N having a reduced stem N, a piston head 0, and a ball valve P. v The reciprocating valve member N fits slidably in the passage 2 provided in the division wall 10, where-as the piston head 0 operates within the piston chamber a, and the ball valve P operates within the valve chamber at. It is to be noted-that the cross sectional area of.

chamber 3 exceeds the similar area of valve chamber 00, and thus the cross sectional area of piston valve 0 is in excess of the area of the ball valve P. Furthermore, the lower side of division wall 10 is shaped to constitute a seat w, and the upper face of the piston head 0 is correspondingly shaped at 0 and is adapted tobe seated into liquidtight contact with the seat w 'on the elevation of the triple valve to the position of Figure 5; The diameter of the stem N of the reciprocating valve is less than the diameter of the passage 2 in the division wall to, and in the lowered position of the triple valve, as in Figure 3, this reduced part N of the valve member N is in the upper part of passage 2, and for a part of its length is opposite to the transverse port a. In said lowered position of the triple valve, Figure 3, the ball valveP rests on a seat provided by the upper face of the division wall w, and upon this ball valve acts an expansion spring 1? occupying the valve chamber a: and contacting at its opposite ends with the ball valve P and a part'of the valve shell M. A relief pipe Q is coupled to theshell M for communication with the transverse port 5, and this relief pipe Q is attached to the return pipe H, see Figure 1, thus affording a common return from the valve I to the pump.

The pipe L being connected with the chamber n of the, control valve I, fluid from said control valve is freeto pass from said valve chamber n. to the valve'chamber w of the Q and pump return H at'a time when the motive fluid is supplied through valve I to pipe it for elfecting the downward movement of the packing plunger. ilfith the packing plung r lowered upon the mass within. one of the cylinders C or C and with the power plunger or mm B moving upwardly, it is apparent that the motive fluid under pressure through pipe 9 into the lower part of the power cylinder, and such fluid under pressure flows also through pipe L into the chamber g at the lower of valve shel M, the packing plunger G, G being still lowered upon the charge within one of the cylinders C, C. Owing to the difference in area of the piston head 0 to the valve P, and to the accumulation of pressure in chamber 3 of the relief valve M, the motive fluid in the chamber 3 operates to impart an upward movement to the piston O and valve member N, displacing the valve P upwardly, and moving the reduced stem N of the valve member N relatively to the port e, such upward movement of the pans beingarrested by the piston head 0 contacting with the seat to on the under surface of the division wall. During the upward travel of the parts N, l Q, the stemN opens the communication between chamber as and port 2 for a brief period, so that the fluid present in the connection from chainber'n' of valve I to the chamber 50 of the relief valve is free to pass out of chamber a: through port 2 to relieve the pressure on the end face of the control valve, Such opening of the by-pass is but momentary, however, because the pressure from cylinder A through pipe L tends to move the piston valve 0 and valve member N upwardly in a continuous manner so that piston head 0 assumes a seated position and valve membcr N travels upward to close the port a, as in Figure 5, and on the continued upward movement of plunger or rain B, the triple valve is in the position of Figure 5 to shut the continued outflow of fluid from chamher it of valve I throu h the 3i e L and the relief valve. On the cessation of flow of the motive fluid to the lower part of the cylinder A, as well as on the downstroke of the plunger or ram B, the pressure is reduced in chamber y of the relief valve, whereupon the spring P acts on the valve P to return it to the seat on the division wall, and to lower theparts N, N, O, to the position of Figure 3, the control valve I having been restored to a I neutral position. v

The operation is apparent from the foregoing description, but may be summarized as follows:

Material is charged in one of the two cylinders C, C, and the cylinders are reversed, so that for the purposes of this specification it is assumed a charged cylinder as C occupies a service position in register with die 1), and power cylinder A, for ram or plunger T B to extrude material from cylinder C through the die, whereas anempty cylinder C is below the packing plunger. The master valve E is operated by hand pressure on lever arm 6, and ram'or plunger B descends slowly Within the cylinder C, but at this time the control valve I occupies a'neutral position (Figure and the packing plunger is elevated within the packing cylinder G. During the slow down movement of ram B, the operator has sufficient time withinwhich to charge the empty cylinder C with a hate of material, and thereupon the operator lifts the lever K from the position of Figure 1 to the upwardly inclined position of Figure 5, the effect of which isto raise the weight K and the stem J, and also to turn the valve plug to the position of Figure 5, for establishing the flow of liquid from pipe H,

through chamber 07/, pipeh, and to the upper partof cylinder G for etl'ecting'the down movement of plunger G, G upon the batch of material in cylinder'G for compacting the same. At this time, the flow of fluid I through valve chamber it allows the fluid to act upon the enlarged end face of theconical part of the valve plug, whereby the pressure of the fluid against said end face'retains the valve plug in the position of Figure 5, and overcomesthe tendency of the weight K to depress the lever K, so that the valve plug remains in said position of Figure 5 during the down travel of the packing plunger, and also for a period of time requiredfor the ram B to complete its down travel and to start on its upstroke. Also, at this time, some of the fluid within chamber nofvalve I passes through pipe L'to ,valve chamber at, and pressure is applied. upon the valve P for holding said valve seated, Figured In the upward movement of ram B to with draw said ram from'cylinder C, the motive fluid supplied from master: valve E by'pipc g to the lower part of cylinderA, accumulates in pipe L, so as to establish a difference in pressurebetween that pressure applied to piston head O and that pressure applied to valve P, with the result that as the ram continues its up movement, the pressure in pipe L exceeds the pressure in pipe L, and hence there is a reduction in pressure upon valve P, and such excess pressure through L acts upon the piston head or valve member 0 to lift the parts N, N, O, P, for moving these parts first to the position of Figure 4, and then to the position of Figure 5. At such movement to Figure 4, the port a is opened to return Q, briefly as described, and the effect is to relieve the pressure through H- and within chamber n, as a result of which the fluid pressure on the enlarged end face of the valve plug is reduced so that the pressure of weight K turns the lever K and valve arm J from raised position (Figure 5) to lowered positions (Figure 4), and alsoto depress the rod or stem J into a lowered position relatively to the bottom part of the cylinder G. Such reversal of lever arms K, J, under the action of weight K overcomes the frictional resistance to the rotative movement of the valve plug (the fluid pressure on which is momentarily relieved as stated), and the valve plug turns from the position of Figure 5 to the position of Figure the flow of liquid being diverted so that the fluid under pressure flows into the lower end of cylinder G for raising the packing plung er, the return of liquid from the cylinder back to the pump due to the travel of the plunger in cylinder G and through the valve. The valve I having been reversed as described, it remains in such reversed position, with the levers K, J, inclined downwardly, during the upward travel of the'packing plunger, but at a certain period in the service of the press, the ram B and the packing plunger both travel upward to withdraw said plungers from the respective cylinders- (1, Q. As the packing plunger nears the limit of its upward travel, the head G strilrcs the lower end of the stem'J, and as the packing plungers containues to rise, the stem J. is

lifted mechanically by the paclung plunger to turn the lever K and the arm J to horizontal positions, and thus restore thev valve I automatically to a'neutral position, at which time the flow of liquid is shut off to the lower part of the packing cylinder, to arrest the up movement of the packing plunger. The flow of liquid continues through the control valve when thevlatter is in neutral position (Figure At the required period,thetriple valve N, O, P, returns to normal position (Figure 3) by the action of spring P when the excess liquid pressure through L is restored to normal upon the completion of the up movement of plunger or ram 13, so that there is no flow through the relief valve at the period of operation of the power plunger and of the operation of the packing plunger except when such relief valveacts for a brief period to permit the reduction of pressure for the automatic reversal of the control valve I to take place by the inertia of the weight II.-

The operation of holding the packing plunger into contact with the material in one of the material cylinders C or C during the period of time required for the to' travel upwardly for the major part of its upstroke may be performed by the operator moving the lever K from the position of Figure 4 to the neutral, position of Figure 3, in which case the quid from the pump flows idly from pipe H, through port a, passage 0), chamber m, and return pipe H, the several parts coacting to retain plunger G in the lowered position and upon the material so as to preclude expansion of said materialwithin the cylinder.

Although I have shown and described fluid 5 actuated means for Voontrol-lingthe' valve I,

such means being dependent upon the return movement of the ram, it is to be understood that my invention comprehends broadly a mechanism, either mechanical or fluid actuated, whereby the upstroke of the rain sets into action the return movement of the packing plunger.

Having thus fully described the invent-ion, whatI claim as new and desire to secure by Letters Patent is:

1. In a hydraulic press, the combination with a hydraulic extruding ram including a controlling valve for effecting the extruding strokeand the return stroke, and a shiftable material cylinder, of a hydraulic packing plunger operable within said material cylinder for applying pressure for a determined time upon a mass to be compressed whereby the density of said mass is increased prior to the action upon th condensed mass of said hydraulic extruding plunger, and fluidpressure means responsive to a return stroke of'the extruding ram for effecting the withdrawal from the material cylinder of said packing plunger.

2. In a hydraulic press, the combination with a hydraulic extruding ram and a hydraulic packing plunger, of a controlling valve mechanism for said hydraulic packing plunger, operable manually for setting the packing plunger into action, and controllable by fluid pressure of the extruding. ram mechanism for effecting the return movement of said packing plunger.

3. In a hydraulic press, the combination with a hydraulic extruding ram and a hy draulic packing plunger, of a controlling valve mechanism for said hydraulic p cking plunger and operable for applying pressure to material during the travel of said extruding plunger and for retaining said material under pressure on the return of said extruding ram, and means responsive to the return of the extruding ram for effecting the return movement of the packing plunger.

4. In a hydraulic press, the combination with a hydraulic extruding ram and a hy draulic packing plunger,- of a control valve mechanism for said packing plunger, operable to impart the working and return movements to said packing plunger, said valve mechanism being under fluid pressure and retained in determined positions by such pressure, and means responsive to the return movement of the extruding plunger for reducing the fluid pressure on the control valve mechanisms, whereby said valve mechanism is operable automatically to effect the return of the packing plunge-r to normal position.

5. In a hydraulic press, the combination- With a hydraulic extruding ram, and a hydraulic packing plun er, of a hydraulic valve for controlling t e movement ofsaid packing plunger by hydraulic pressure, said. hydraulic valve including a by-pass inliquid,

connection with said hydraulic. extruding ram and said valve being responsive to a variation in fluid pressure for effecting the return movement of said packing plung 6. In a hydraulic press, the combination with a hydraulic extruding rain, and a hydraulic packing ger, of a controlling valve for said pac is :tor manually operating s responsive to the action of plunger for relieving said control valve the action of fluid pressure, reversing said valve upon a reduction of pressure thereon.

in a hydraulic press, the combination with a hydraulic extruding ram, and a hy draulic packing plunger, of a controlling valve for said packing plunger, means actuated by said extruding plunger mechanism tor relieving said control valve from the resaid straint of pressure, means for reversing said control vs. vs. and plunger operated means for restoring the control valve to neutral'p sition.

8. In a hydraulic press, the combination with a hydraulic extruding ram. and a hydraulic packing plunger, of a control valve for said packing plunger, said control valve being seated by fluid pressure, means for relieving said control valve from fluid pressure, said means being responsive to the return movement of said extruding ram. means associated with said control valve, whereby it is reversed when relieved from the eflfect of pressure, and plunger operated means for restoring the control valve to neutral position.

9. In a hydraulic press, the combination with a hydraulic extruding ram, and a hydraulic packing plunger, of a control valve for said packing plunger, said control valve bein under the influence of hydraulic pressure, a by-pass connected with the extruding plunger and said control valve, relief valve in said by-pass and means operable for reversing said control valve upon a reduction in pressure thereon.

10. In a hydraulic press, the combination with av hydraulic extruding. ram, of a hydraulic packing plunger, and fluid actuated means responsive to the movement or" said extruding ram for eflecting the automatic return of said packing plunger to normal position.

11. In a hydraulic press, the combination with charging means and a hydraulic extruding ram, of a hydraulic packing plunger cooperable with said charging means, and fluidactuated means responsive to the movement of the extruding ram for effecting the withdrawal of the packing plunger from said charging means.

12. In a hydraulicpress, the combination with material-carrying -means, and a hydraulic extruding ram, of a hydraulic packwith the return. of said extruding plunger.

14. in a hydraulic press, the combination with an extruding ram including valve mech-. anism for controlling fluid pressure to eflect the extruding stroke and the return stroke of said ram. and a shii'table material cylinder, of a. fluid pressure actuated packing plunger operable for a determined time by such fluid pressure in applying a compressive force to mass present within said material cylinder, whereby the density of said mass is increased by the action of fluid pressure pior tothe' extrusion of said mass by the extruding ram, and a separate controlling valve for initiating the action of fluid pressure on said packing plunger.

15. In a hydraulic press, the combination with a hydraulic extruding ram including valve means for controlling fluid pressure in eiecting the extruding movementand the return movement of said ram, and ashiftable material cylinder, of a hydraulic packing plunger including controlling means whereby thecompression stroke is influenced by fluid pressure, and means actuated by a variation in fluid pressure for effecting the return stroke of the packing plunger concurrently with the i return stroke of the extruding plunger.

16. In a hydraulic press, the combination with a hydraulic extruding ram including valve means for the fluid pressure, and a shiftalole material cylinder, of a hydraulic packing plunger co-operable with said cylinder when the latter is shifted to a charging position, a separate valve for controlling said packing plungen means for relieving said separate valve from fluid pressure, and means for shifting said separate valve upon avariation of the fluid pressure.

17. In a hydraulic press, the combination with an extruding ram including valved means for controlling the action of fluid pressure on said ram, and a shiftable material cylinder, of a hydraulic packing plunger, 2.

separate valve for controlling the action of fluid pressure on said packing plunger to initiate the compressing stroke thereof, means for reducing pressure on said separate valve, means for shifting said separate valve upon the variation of said fluid pressure, and

plunger operated means for returning the se aerate valve to normal position.

18. In a hydraulic press,'the combination with an extruding plunger mechanism including a valve for controllingthe action thereon offluid pressure, and a shiftable material cylinder,- of a hydraulic packing plunger, a separate valve for controlling the action of fluid pressure'on said packing plunger to initiate the compressing stroke thereof, a lay-pass with a relief valve, said by-pass being 7 co-operablevvith the fluid pressure means of said packing plunger, whereby the fluid pressure is varied on the separate valve, and means for actuating the separate valve.

19. In a hydraulic press, the combination with an extruding ram including a valve'for controlling the action of fluid pressure thereon,and a material cylinder, of a hydraulic packing plunger mechanism including a separate valve for initiating the action of the fluid pressure in imparting the compressing stroke to the packing plunger, means for effecting variation in the pressure on said separate valve, and a Weighted arm for reversing the separate valve upon such variation in pressure.

20. In a hydraulic press, the combination with a hydraulic extruding ram, and a shiftable material cylinder, of a hydraulic packing plunger mechanism including a separate valve for controlling the action of fluid pres sure to initiate the compressing stroke of said plunger Within said cylinder, means for effecting a variation of the fluid pressure on said separate valve, whereby said separate valve is controlled to reverse the travel of the packing plunger, and valve actuating means coacting with said packing plunger for restoring said separate valve to neutral position.

21. In a hydraulic press, the combination with a hydraulic extruding ram, and shiftable material cylinder, of a hydraulic packing plunger mechanism including a separate valve for controlling the action of fluid pressure in effecting the movement of said packing plunger, means for effecting the variation in the pressure of said fluid'on the separate valve, means for reversing said valve, and a member operated by the packing plunger for restoring said separate valve to neutral position. 7 I

In testimony whereof I have hereto signed my name this 7th day of July, 1926.

JOSEPH DE FRANCISCI.

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