US1932556A - Press - Google Patents

Description

t. 31, 1933. P. v. J. MERENDA ,9

PRESS Filed Sept. 8, 1950 4 Sheets-Sheet l Oct. 31,? 1933. P. v. J. MERENDA PRESS Filed Sept. 8, 1950 4 Sheets-Sheet 2 iNVENTOR 06%. 31, 1933 P. v. J. MERE-NBA 31 932 5 56 PRESS Filed Sept. 8, 1930 4 Sheets$heet 3 Fly, 5

. 1/NVENTOQ Get. 31, 1933.

P. v. J. MERENDA 1,932,556

- PRESS Filed Sept. 8, 1930 4 Sheets-Sheet 4 lNvEN'TOR 19 ,42 .WHA/

Patented oct. 31, 1933 PATENT? OFFICE mass Paul V. J. Merenda, Fontenay-aux-Roses, France, assignor to The Turner Tanning Machinery Company, Portland, Maine, a corporation of Maine Application September 8, 1930, Serial No. 480,405, and in Germany September 28, 1929 14 Claims. (Cl. 138-17) This invention relates to presses and is illustrated as embodied in a press of. the hydraulic type designed for use in smooth plating, embossing and other pressure applying operations upon hides, skins, leather and other similar pieces of work. It is to be understood, however, that the invention and various important features thereof may have other applications and uses.

In a well-known type of hydraulic press, one

of the presser members is moved toward the other to effect pressure applying operations by means of a hydraulically operated piston which is operated by an auxiliary piston designed to serve also as a valve mechanism for controlling the application of a pressure medium under pressure to the first-mentioned piston. "It is a disadvantage of such prior constructions that little,i1 any, variation in the thickness of the work or in the resistance encountered by the auxiliary piston before the application of pressure to the mainpiston is permissible, since if the resistance be too great the auxiliary piston cannot move sufilciently to initiate the application of pressure directly to the main piston. Even if the work be compressible to such degree as to permit movement of the auxiliary piston to the point of initiating the application of pressure directly to the main piston, such movement of the auxiliary piston may be so slow as to render the press valueless from the standpoint of productive capacity.

It is an object of this invention to provide an improved press of the type described whereby the productive capacity of the press may be substantially greater than heretofore, since work varying considerably in thickness or in the resistance offered to the movement of the pistons may be acted upon in the improved press without appreciably slowing up the speed of the press.

To these ends and in accordance with an im- 40 portant feature of the invention a piston supporting the movable platen of a press is arranged to be moved by an auxiliary piston constructed and arranged to travel upwardly always the same predetermined distance, with respect to the cylinmedium is applied under pressure directly to the first-mentioned piston. By this arrangement movement of the movable platen to close the gap between the fixed platen and the movable platen with the work thereon. is accomplished in minimum time, a lost-motion connection between the pistons being provided to accommodate variations in the thickness of the work. As illustrated 5 a simple and compact spring means is provided 0 ders enclosing the pistons, before the pressure between the pistons, the tension of the spring means being such as to support and cause movement of the main piston and of the platen associated therewith until such platen and piston meet with substantial resistance from the work. When the platen moved by the piston commences to encounter substantial resistance from the work the spring means begins to yield, permitting the auxiliary piston to continue its movement to effect control of the application of hydraulic pressure directly to the first-mentioned or main piston.

It is a further important feature of the invention that the main piston is mechanically connected to operate a valve to open position to permit of the escape of the pressure medium back of the main piston so that the latter may return to initial position following a pressure applying operation. .Advantageously, this valve mechanically operated from the main piston isembodied in an organization wherein only one passageway is provided for carrying the pressure medium to and away from the cylinder associated with the main piston.

In an illustrated embodiment of the invention, an important feature of the invention resides in the provision of a port and passageway in the internal walls of the cylinders to afford communication between the cylinders under control of the auxiliary piston. This arrangement issimple and durable and efllcient for the purpose intended, since it reduces the number of'pipes and pipe openings into the cylinders and minimizes the possibility of leakage from the cylinders during applications of pressure upon the work.

These and other features of the invention and novel combinations of parts will now be described in detail and then pointed out in the appended claims.

In the drawings,

Fig. 1 is a front view, partly in section, showing important features of a press illustrating one embodiment of the invention;

Fig. 2 is a side elevation of the press shown in Fig. 1, certain parts being in section taken alon the line IIII of Fig. 1;

Fig. 3 is a plan view from below, and partly in section, of means for operating one of the valves from the lower platen of the press;

' Fig. 4 is a plan view from above and partly in section showing certain valves and a manually operable member by means of which the operator secures control of the'press:

Fig; 5 is'aview in front elevation of a press of simplified. construction which also embodies im-'- portant features of the invention;

Fig. 6 is a view in side elevation of the press a downwardly facing portion of a C-shaped frame 4, the platen 2 being arranged to be heated in a well-known manner by steam pipes 6 and 8 (Fig. i). For co-operation with the upper platen 2 there is provided a lower platen 10 arranged to be carried by a piston 12, a movable connection being provided between the platen 1c and the piston 12 by means of a boss 14 on the. platen 10 having a spherical surface resting upon a complementally curved spherical surface formed as a socket 16 in the upper end of the piston 12. The purpose of the movable connection between the platen l0 and. the piston 12 is to permit adjustment between the platen l0 and the platen 2 so that these platens will accommodam self-adjustingly pieces of work wherein a substantial portion or the work differs irom other portions oi the same piece of work in thickness dimensions. As shown. the piston 12 is'movable vertically in a piston cylinder 18, and, by preference, upwardly by pressure exerted by an auxiliary piston 20 (Fig. 2) concentrically arranged with respect to the large piston 12. As illustrated, the auxiliary piston 20 is movable vertically within a piston cylinder 22 which has a port 24 for the admission of a liquid medium under pressure. It will be readily understood that, upon admitting liquid medium under pressure through the port 24 the auxiliary piston 20 will be forced upwardly, thus '-lifting the piston 12 and with the latter the platen 10, so that a piece of work supported upon the upwardly facing work supporting surface of the platen 10 will be pressed against the downwardly facing surface of the platen 2. a

in order to insure that the large piston 12 will be moved, throughout substantially its entire upward stroke, by the auxiliary piston 20,

irrespective of the thickness or the work interwed between the two platens l0 and 2, there is provided in the illustrated construction a yielding or a lost motion connection between the two pistons 12 and 20. As shown, this yielding connection comprises a spring 26 arranged to surround a reduced portion 28 of the piston 20. In order to tension the spring 26 there is provided a plate 30 slidable upon the piston part 28,

a nut 32 being screw threaded upon the end of the piston part 28 so that it may be adjusted to cause the plate 30 to exert the required pressure upon the spring 26. Preferably the nut 32 with the plate 3i) will be adjusted to tension the spring 26to such an extent that the spring will slightly more than support the piston 12 and the platen 10 without yielding. Hence, when the platen it starts to press the work against the platen 2 so that the piston 12 encounters the resistance of the work, the spring 26 is compressed due to the sliding connection between thetwo pistons, thus permitting the auxiliary piston so to move upwardly always tothe same point, irrespective of the thickness of the work being operated upon. lt is clear that the spring 26 is compressed when it meets a resistance predetermined by the tenncsasse sion of the spring secured through adjustment of the plate 30 and nut 32. This point to which the auxiliary piston 20 rises is determined by a port or ports 34 in the auxiliary piston 20, the port or ports as being at the upper end of a passageway or bore 36 axially located in the auxiliary piston and communicating at its lower end with the chamber within the piston cylinder 22. It will be clear that upon applying liquid medium under pressure to the lower end of the auxiliary piston 20 the latter will be forced upwardly, thus carrying the large piston 12 and the platen 10 into pressure applying relation with respect to a piece or work between the platens 10 and 2 and 7 that the auxiliary piston 20 will continue to move upwardly until the port or ports 34 are in position to open into the chamber of the main piston cylinder 18. When this occurs the pressure in the cylinder 22 is instantly communicated to the liquid medium within the piston cylinder 18. Pressure is then gradually built up within the piston cylinders 18 and 22 whereby the required pressure on the work between the platens is obtained. It is to be noted, moreover, that the movement of the main piston 12 to a point where pressure on the work begins is accomplished by the auxiliary piston 2c irrespective of the thickness oi'the work, this arrangement insuring the desired speed in the upward movement of the piston 12, as will be pointed out more clearly hereinaiter.

While the piston 12 is being moved upwardly by the auxiliary piston 20, a liquid medium is flowing into the piston cylinder 18 through a pipe to into which the liquid passes from a pipe 42, a valve 44 in valve box or casing 45 beingtree to move upwardly. Since the piston 12 during its upward movement within the cylinder 18 acts as a suction piston, liquid will be drawn from a reservoir (not shown) through the pipe 40 past the valve 44 which would thus be lifted by the entering liquid even if no other means were provided for lifting the valve. It follows that the space within the cylinder 18 below the piston 12 is completely occupied by liquid at the time that the port or ports 34: in the auxiliary piston 20 arrive in communicating relation with respect to the cylinder 18. Hence, movement of the piston 12 during the building up of the pressure within the cylinders 18 and 22 and compression of the work is dependent upon a minimum amount of fluid passing from the cylinder 22 through the port or ports 34 to the cylinder 18. If a considerable amount of liquid under pressure had to pass through the restricted port or ports 34 into the cylinder 18 during upward movement of the pistons 12 and 20, this {upward movement of the pistons would be considerably slower than in the construction shown. In other words, the necessary amount of liquid medium to apply pressure to the bottom surface of the piston 12 is practically all in the cylinder further upward 18 at the time the port or ports 34 reach the through'a passageway 52 in a valve block 54 to a pipe 56 connected with a pipe fitting 58. Leading from the pipe fitting 58 is a pipe 60 (Fig. 2) which terminates at the port 24 in the the ball valve 66 while pressure is being built up within the cylinder 18 since the same pressure is being built up within the chamber 64 as within the piston 18. When, however, pressure within the pipes 60 and 62 and within the auxiliary piston cylinder 22 is released, by means which will subsequently be described, the ball valve 66 will serve as a quick acting release for the liquid under pressure in the piston cylinder 18 through the communicating pipe 40 so that the piston 12. may start its downward movement by discharging liquid past the ball valve 66, the course of this liquid being through pipe 62 (Fig. 1), pipe fitting 58, pipe 56, passageway 52, thence through a port 68 and a passageway '70 leading by. the pipe 42 back to the tank or reservoir (not shown) In order to facilitate discharge of the liquid pressure medium from the piston cylinder 18 as the piston 12 moves downwardly, means is provided for lifting the valve 44 so that liquid may escape from the pipe 40 to the pipe 42 which leads to the tank or reservoir. Conveniently, the means just referred to is controlled by connections with the platen 10 and comprises a rod serving as a valve stem 72 (Fig. 2) located below and in line with the axis of the valve 44, the rod or valve stem 72 being pivoted at 74' (Figs. 1 and 3) to a crank arm 76 secured to a shaft 78 mounted in bearings furnished by brackets 80 and 82 secured to the frame 4 of the press. Also secured to the shaft 78 are links 84 and 86 (Figs. 1 and 3) pivoted at their other ends to links 88 and 90 which at their upper ends are pivoted to ears 92 on the platen 10. It will be clear from an inspection of Figs. 1, 2 and 3 that as the platen 10 moves downwardly the shaft 78 will be rocked whereby the rod or valve stem '72 will be lifted to unseat the valve 44. the valve 44 rising higher as the piston 12 descends and thus affording a gradually enlarged passageway, in addition to the pipe 62, for the liquid to pass from the cylinder 18 through the pipe 40 and 42 back to the reservoir or tank.

Means is-provided for enabling the operator to initiate a pressure applying operation, the same means being conveniently operable to terminate a pressure applying operation. In the construction shown the means just referred to comprises a hand lever 93 (Fig. 1) movable about the axis of a vertical pin 95, the hand lever having a segmental gear 9'7 (Figs. 1 and 4) arranged to be in mesh with a pinion 99 having screw threaded engagement with stem 101 of a valve 103. When the handle portion of lever 93 is drawn toward the front of the machine the valve 103 is moved toward the port 68 to close the latter, thereby forcing the liquid from the pump to pass along the passageway 52 and by way of the pipe 56 to the pipe coupling. 58 from which the liquid under pressure is carriedby pipe 60 to the auxiliary cylinder 22. In this way the operator can initiate a pressure applying operation whenever he has a piece of work properly disposed upon the platen 10. In order to provide for escape of the liquid under pressure when the pressure rises above a certain predetermined amount, there is provided a spring pressed valve 105 (Fig. 1) the stem of which is movable in a valve cylinder 107 which encloses also a spring 109 which may be adjustably tensioned by a set screw 111 arranged to press upon a plate 113 resting upon one endof the spring 109. When the spring pressed valve yields upwardly, the

pressure is relieved by fluid escaping through the passageway 70 and pipe 42 back to the tank or reservoir. While the liquid under pressure from the pump may be allowed to continue to build up pressure within the piston cylinders 18 and 22 until pressure is released by the yielding of the spring pressed valve 105, it is to be understood that the operator may terminate a pressure applying operation at any time simply by moving the hand lever 93 toward the back of the machine, that is, in a direction the reverse of that which secures initiation of a pressure applying operation. When the hand lever 93 is turned in the direction away from the front of the press, the valve 103 is lifted away from the port 68 so that liquid from the pump coming in through the pipe 50 may pass through the port 68 to a passageway 70 which connects with the pipe 42 which leads directly back to the tank or reservoir.

In operating the illustrated press, assuming that the platen 10 is in lowered work receiving position, the piece of work is introduced upon the upper face of the platen 10 and smoothed out by hand or otherwise to remove any wrinkles or folds in the work. As soon as the work is properly conditioned for a pressing operation, the operator pulls the hand lever 93 toward the front of the machine, thus causing the valve 103 to close the port 68 whereby liquid under pressure is caused to pass from the pump to the auxiliary piston cylinder 22. Upward movement of the auxiliary piston 20 lifts the main piston 12 and presses the platen 10 with the work thereon against the upper platen 2. No matter what the thickness of the work the piston 12 is caused to travel throughout substantially its complete upward stroke through pressure exerted by the auxiliary piston 20, work of different thicknesses being properly taken care of through the yielding of the spring 28 interposed between the two pistons. Since the illustrated construction is specially designed for smooth plating and embossing operations on hides, skins and pieces of leather, the range of thickness is relatively small. When the port or ports 34 in the auxiliary piston 20 arrive at communicating position with respect to the piston cylinder 18 pressure in the liquid pressure medium is transmitted instantaneously from the auxiliary cylinder 22 to the piston cylinder 18 and pressure is gradually built up in the pistonqcylinder 18. Whatever slight upward movement of the piston 12 takes place in smooth plating or embossing operations upon the work, involving a certain compression of the work, is caused by liquid under pressure passing through the port or ports ,34 into the pfston cylinder 18. Since, however, the piston 18 is substantially or nearly at the end of its upward stroke when the port or ports 34 reach communicating position with respect to the cylinder 18, there is provided an arrangement wherein the very minimum amount of liquid must pass through the restricted port or ports 34. In other words, procticolly oil of the upward movements oi the piston 16 hos been coused directly by the ewziliory piston in in on etious mer. When the operator decides that the plating or embossing operation hes been soiisiuctorily per= formed, he re uuzzfl the operoiion by mo the handle lever 93 away lrorn the front of the press. As beforestoted, this opens-the port so, thus allowing the liquid from the pump to es cope heck to the t or reservoir. As soon as the port so is opened pressure in the liquid in the auxiliary cylinder 22 1w. 1 foils, this being true also of the pressure in'the pipe 82 heck of the hull vnlve 036 so that Tooth usmy move downwardly displocing the liquid in their respective cylinders until the ploi'en iil hm returned to its initiol work recei position. The work which has been opere'bed upon is then removed and o fresh piece inserted as e pre cry to repetition oi the operotions lust de= scri The press disclosed in Figs. 5, s, end 7 oil the wings represents a. simplificotion in certoin respects of the press described in the foregoing porphs. Nevertheless it pos r -i 1? of the important lectures and odtoges of the press first described; This simplified press com- 1 on upper picien 102 i i red fixedly by e heovy ire member 1% secured by bolts we to as lower femher 10d. For :3 m in. the upper c is miner 1M and for rtdedcchon oi the e member 1%, there ore vided two heovy burs for rigidly connecting the in member 1min frame u; or roe, one oi? ntllilinlfido.

For co-oting witch the upper ploten 102 there is provided o pinion 112 having on upword 1y facing work supporting; surioce, the pier/en 112 being mounted by as hell and socket ioini, lid, 116, in o piston lid. As shown, the piston 11% is supported in n cylinder 12d wi which it is i fluid-tight m.

For liiting'izhe piston 118 there is provided on auxiliary piston 122 indicated in dotted lines in Fig. 5 amd shown in cross sect-ion in Fig. 7 of the drawings. piston 122 is very much the here being sh smaller than piston 11% end is fitted to slide withthe 11' in or ii cylinder or bore 124. When-should medium under pro is sited through to pipe 126 end throuuh u port 127 into the lower end of the cylinder or more 124i, the euxilimi' pisoon 122 is coused to move upwsrdly f m with it the large piston 11%. As shown most cleorly in Fig. 5 oil the drawings, ihepipe 12d isvconnected with or pump 12%, u port 130 (Pin. i) in the pipe 126 being provided oi; :2 point convenienily situated for control by the operolor. en the port,1il is closed, as indicoted in Fig. end 833 shown in his. 7, the liquid medi under r is'coused to flow from the pp 128 do the cylinder or bore 12% of the eiory pn 122. To interrupt the application of pressure to 121$! piston 122 it is necessary only to open'the porji; ldil'hy to i-m as hand wheel 132 v fastened to n vslve pin 1% having as screw threaded engssemeni; iii; 1% with n vulve cup 13%. Upon turning the hond wheel 132 in o counterclockdirection in Figs. 5 end l, o cone-pod end no of the volve pin 1% is retracted so t the liquid medi Ina under 9 own-31 in the pipe 12d ihe prossis'iobeopere ldd (Fig. 5) is in lowered position so thnt e port 150 is open to permit of the p oi she liquid medium mung the pipe 1% to the cylinder no. As shown, the valve 148 is secured in the lower end oi a. valve stem 152 to which is fixedly etteched o disk movable in o. cher surrounding en intermediate portion oil the valve stem 152, e spring 156 being provided which tends olweys to move the vnive 1% to its portclosinc position. However, the port 156) is open dg procticolly oil of the upward movement.

oil the piston 118, the valve 148 at no lowerend oi the stem 152 being held downw e :r owoy from the port 15o through means conncc with the piston 118. This control of mi M8 by the piston 118 is eflecoed in the illted consction by a lever ice pivoted st 162 between s poir of links 16% in turn pivoted st 1% to velve casing idd, the lever we having is shallow recess for the reception oi e upper rounded end 169 oi the valve stem 152. Convenienth i'he other end'oithe lever 180 is rounded end received as or hell end in e socket form in e who no secured u the piston 11% near end thereof. Preierohly; and as sh the roded end or the v .2 152 is fo as c m -W l and is screw a sded on the r us so he adjustable. on work or o suiostoniw ihei lost crested in upon, ihe meher 169 should he adjusted hily in e downward direction on-the valve stem '52 so m to open the port 15o conly her.

As illustrated, means is p ovided for npplyine the liquid under pressure directly to the lower end oil-the lorse' pn 118. in orderto eocomp' in a; pie and 'eihcient, ner withou the provision oi o velve, such provided in the post, the x mm? iii -piston 122 is mode to serve =11 volve piston. in order to uccompiish this as .o

i: one or more 1T2 (Figs. 5 and i) are provided in the in w of the nuxilisry pisy con cylinder 12% by which the liquid medi under pr pass into the piston his. her no and thus not directly on the piston l 8' oi: e 1.1.111 point in the upw movement oiihe i' w: 122. As shown, the ports 1'72 ore of restricted ores, being in the form of slots, the 1 "firm: of eech slot exten in the direction of the length of the port-s 172 are gradually sud progressively uncovered to l the liquid pressure medi into (the cylinder me from the cylinder 124. As soon as these ports are opened the pressure in the high pressure medium in the pipe 12c and in the cylinder 12% is tr- .rari; instantaneously to the liquid medium within the cylinder 12!). Hence, the is. pressure of the pump is transmitted directly to the piston 11%. In order thst this may he occoplished, lthe srreneement, inciudind the position or the piston 11s, is such direction, whereby the port 130 is opened, thus that at the instant of opening the ports 172 the valve 148 closes the port 150, thus confining the liquid pressure medium within the cylinder 120 under the piston 118. As the ports 172 are gradually uncovered the liquid medium may flow the faster into the space within the cylinder 120 and thus progressively increase the upward movement of the piston 118. This gradual entrance of the liquid medium under pressure from the cylinder 124 into the cylinder 120 has the effect of securing a smooth and continuous upward movement of the piston 118 and platen 112 and gradual application of pressure to the work interposed between the platens 112 and 102. It is to be understood that the amount of liquid entering the cylinder 120 through the ports 172 is very small indeed. When the piston 118 has practically reached its final upward position the pressure is gradually built up in the cylinder 120 until the full pressure provided for by the press is obtained. The amount of this pressure is regulated through a valve of well-known construction located at 174 (Fig. 5), the amount of such pressure being determined in a well-known manher and indicated by the indicator dial shown at 176. Any tendency to exceed such predetermined pressure results in escape of the liquid from the pipe 126 through the valve 174 and a pipe 178, the upper end of which discharges into the reservoir 144.

When the press is at rest with the piston 118 in its lowermost position, a piece of work may be readily introduced between the upper platen 102 and the work-supporting surface of the lower platen 112. At this time the liquid medium is circulating without interruption, as it is being pumped by the pump 128 through the pipe 126, thence through the port 130 and pipe 142 back to the reservoir 144 from which it again passes by means of a pipe-180 to the pump 128. When the operator is ready to start a pressure-applying operation, he turns the hand wheel 132 in a clockwise direction thereby causing the valve 140 to close the port 130. This immediately cuts off circulation of the liquid medium through the pipe 142 to the reservoir 144 and forces the liquid medium under pressure through pipe 126 into thecylinder 124 through the port 127 at the bottom of the cylinder. The auxiliary piston 122 is caused to rise, at the same time lifting the main piston 118 upwardly in a direction toward the upper platen 102. During the time that the piston 118 is rising, liquid from the reservoir 144 is drawn into the cylinder 120, since the port 150 in the pipe 146 is open at this time. Even if the valve 148 were not depressed by the lever 160, it would be forced downwardly to admit fluid from the reservoir 144 due to the suction effect of the rising piston 118. As the piston 118 and the auxiliary piston 122 are approaching the termination of their upward movement the ports 172 are uncovered and at the same time the port 150 is closed by the valve 148. After the piston has reached substantially its final upward position, pressure is built up in the cylinder 120 to a point determined by the setting of the valve 174, it being obvious, however, that the operator may terminate the application of pressure at a point selected by himself while watching the indicator 176. The pressure for smooth plating or embossing the piece of work between the platens may be continued for any length of time determined by the operator. All the operator must do to terminate the pressure-applying operation is to turn the hand wheel 132 in a counterclockwise permitting the liquid medium to escape through the port 130 and pipe 142 to the reservoir 144. When this happens both the piston 118 and the auxiliary piston 122 move downwardly, due to escape of the pressure medium through the slots 172, and the valve 148 is opened in a positive manner'by the piston 118 thereby securing instant release of all pressure since the liquid in the cylinder 120 may then'escape through the pipe 146 into the reservoir 144. Fromone viewpoint, it is the escape of liquid through the ports 172 that initiates return of the large piston toward its initial position of rest. Escape of the liquid fromcylinder 120 along the pipe 146 takes place all the time that the piston 118 is descending to its initial position of rest. When the piston 118 and platen 112 have reached their lowermost or work-receiving position, the piece of treated work is removed, and a fresh piece inserted as a preliminary to repetition of the described operations.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a hydraulic mechanism, a piston, an auxiliary piston movable for moving the first-mentioned piston, means for applying pressure to the auxiliary piston to cause movement thereof, means controlled by theauxiliary piston for applying a liquid under pressure directly to the first-mentioned piston, a valve mounted outside of and independently with respect to both pistons, and connecting members between the valve and the first-mentioned piston arranged to operate the valve positively to open position for releasing liquid so that the first-mentioned piston ma return toward its initial position.

2. In a hydraulic mechanism, a piston, a cylinder enclosing said piston, an auxiliary piston movable for moving the first-mentioned piston, means for applying pressure to the auxiliary piston to cause movement thereof, means controlled by the auxiliary piston for applying a liquid under pressure directly to the first-mentioned piston, a valve casing mounted rigidly outside of and in parallel relation with respect to said cylinder, 'a'valve in saidcasing, and a positive mechanical connection between the valve and one of the pistons to cause operation of the valve to effect release of liquid applied under pressure directly to the first-mentioned piston.

3. In a hydraulic mechanism, a piston, an auxiliary piston movable for moving the' firstmentioned piston, means for applying liquid under pressure to the auxiliary piston to cause movement thereof, a cylinder enclosing the firstmentioned piston, a cylinder for the auxiliary piston, a port arranged to be alternately opened and closed by the auxiliary piston itself serving as a valve during movement thereof for affording a communication between the two cylinders, whereby pressure is applied directly to the firstmentioned piston by liquid under pressure in the two cylinders; a valve and means connecting the valve to the first mentioned piston to effect release of the liquid, applied under pressure directly to the first-mentioned piston, in timed relation to the movements of said first-mentioned piston.

mentioned piston, means for applying a liquid der for the first-mentioned piston, a cylinder for the auxiliary piston, means to apply liquid under pressure to the auxiliary piston the latter piston having a port and passageway arranged to connect the auxiliary piston cylinder with the cylinder for the first-mentioned piston whereby liquid under pressure may pass from the auinliary piston cylinder to the first-mentioned piston cylinder, means for releasing pressure of the liquid pressure medi on the auxiliary piston so that the auxiliary piston may re-enter its cylinder, thus relieving pressure on the first-mentioned piston, a release valve, and a rod pivotally connected to the first-mentioned piston and arranged to lift the valve upon release of the firstmentioned piston by the auxiliary piston to permit escape or the liquid pressure medium from the first-mentioned cylinder so that its piston may return to initial position.

5. In a press, co-operating platens for applying pressure to oppositesurfaces of pieces of work,

' cylinder for the till till

a piston for moving one of the platens toward the other, an auxiliary piston for moving the first-mentioned piston, means for applying a liquid under -p e to the auxiliary piston, a

-mentioned piston, a cylinder for the ary piston, the latter piston having a port and passageway connecting the auxiliary piston cy v, .3 er with the cylinder of the first-mentioned piston whereby liquid under pressuremay pass from the auxiliary piston cylinder to the first-mentioned piston cylinder, a manually operable valve for reinre-enter its cylinder, thus relieving pressure on the first-mentioned piston, a valve controlled by the release of pressure upon the auxiliary piston, to relieve pressure on the flrstmentioned pistonso that it may return to its initial position, and a valve operated mechanically from the firstmentioned piston to open position to facilitate discharge of the pressure medium from the drstthe first-mentioned piston upwardly, a cylinder for the auxiliary pisto the latter piston having a port and passageway for connecting the auxiliary piston cylinder with the cylinder of the first-mentioned piston, means for applying a liquid under pressure to the auxiliary piston, the arrangement beingsuch that at a predetermined point in the upward movement of the auxiliary piston the port is uncovered so that liquid under pressure is applied directly to the first-mentioned piston, means for supplying a liquid pressure medium to the cylinder oi the first-mentioned piston, a valve controlled by the first-mentioned piston for retaining the liquid medi under pressure under said piston just as the lat-- ter reaches its. high point in its pressure applying operation, a sec nd valve for retaining the pressure medium ton, and means for simultaneously releasing pressure on the d": :1 piston and on the second valve, whereupon. the. first-mentioned piston moves downwardly and releases said first-mentioned valve, thus petting. escape of the liquid medium from under the first-mentioned piston hereupon the latter returns to its initial posit. he a p, co ratlnig platens for app r at pressure on the. auxiliary-piston so t the auxiliary piston may er the first-mentioned plsnaaasee under pressure to the auxiliary piston, .a cylinpressure to opposite surfaces of pieces of work, a piston for moving one of the platens toward the other, an auxiliary piston movable for moving the first-mentioned piston, means for applying a liquid under pressure to the auxiliary piston to cause movement thereof, a cylinder for enclosing the first-mentioned piston, a cylinder for the auxiliary piston, said cylinders having a common opening normally filled by the auxiliary piston, a connecting passageway between the two cylinders wholly within the internal walls of the latter and controlled by the movable auxiliary piston for securing application of the liquid pressure medium directly to the first-mentioned piston, and means comprising said connecting passageway arranged to provide for release of pressure in the cylinder of the first-mentioned piston.

8. In a press, co-operating platens for applying pressure to opposite surfaces of pieces of work, a piston for moving one of the platens toward the other, an auxiliary piston movable for moving the first-mentioned piston, means for applying a liquid under pressure to the auxiliary piston to cause movement thereof, a cylinder for enclosing the first-mentioned piston, a cylinder for the auxiliary piston and having wholly within its internal wall both a port and a passageway for connection with the first-mentioned cylinder, the movable auxiliary piston being imperforate and arranged to operate alternately to close and to open the port whereby the liquid pressure medium entering the auxiliary cylinder may pass at a predetermined time into the cylinder oi the first-mentioned piston to act directly thereon, and means comprising said port andpassageway arranged to provide for release of pressure in the cylinder of the first-mentioned piston. t s

9. In a press, co-operating platens for treating'115 a piece of work, a piston for moving one or the platens toward the other, an auxiliary piston for moving the first-mentioned piston, means for applying a liquid medium under pressure to the v auxili f pi ton, a cylinder enclosing the firstmentioned piston, a cylinder for the 91411321.? piston, and a lost-motion connection between the two pistons arranged to become operative after the first-mentioned piston and the platen moved thereby meet the resistance offered by the other platen, the auxiliary piston having a port and a passageway arranged to be controlled by the auxiliary piston to permit liquid medium under pressure to pass from the auxiliary piston cylinder to the first-mentioned piston cylinder always 139 at the same point in the movement of the auxiliary piston with respect to said cylinders, whereby llquid medium under pressure is applied directly to the first-mentioned piston at a predetermined point in the upward movement or the auxiliary piston irrespective of the thickness of the worlr mterposed between the two platens. I 1c. in a press, co-operating platens for treating a piece of work, a piston for moving one of the platens toward the other platen, an auxiliary my piston for moving the first-mentioned piston, means for applying a liquid medium under pressure to the auxiliary piston, a cylinder enclosing the flrst-mentionedpiston, a cylinder for the aux-' 'iliary piston, a sliding connection between the two pistons arranged to become operative when the first-mentioned piston meets a predetermined resistance ofiered by the work, and a port arranged to be controlled by the auxiliary piston to 1- t liquid medium under pr to pm from the i platens toward the other platen, an auxiliarypiston for moving the first-mentioned piston, means for applying pressure to the auxiliary piston, a

port through which a liquid medium under pressure is admitted to said cylinder, the auxiliary piston being arranged to open the port always at the same point in its movement relative to said cylinder irrespective of the thickness of the work, and spring means interposed between the-two pistons, said spring means being arranged to supportthe first mentioned piston and to yield to accom modate work of different thicknesses between the platens;

12. In a press, co-operating platens for treating a piece of work, a piston for moving one platen toward the other, an auxiliary piston for moving the first-mentioned piston, means for applying a liquid medium under pressure to the auxiliary piston, a cylinder enclosing the first-mentioned piston, a cylinder for the auxiliary piston, a spring connected to the auxiliary piston, a plate associated with the spring, and means for adjusting the plate to tension the spring so that the spring will support the first-mentioned piston and yield only when said piston encounters a predetermined resistance, said auxiliary piston having a passageway and a port serving as a communicating passageway between the two cylinders, and the auxiliary piston being arranged to control the port upon yielding oi the spring to permit liquid medium under pressure to pass from the auxiliary piston cylinder to the first-mentioned piston cylinder.

13. In a press, co-operating platens for treating a piece of work, a piston for moving one of the platens toward the other, an auxiliary piston for moving the first-mentioned piston, means for applying a liquid medium under pressure to the auxiliary piston, a cylinder enclosing the first-mentioned piston, means for supplying a liquid medium to the cylinder and putting it under pressure comprising a port opening into the cylinder, the auxiliary piston being arranged to control said port always at the same point in the movement of the former relative to said cylinder, and a spring associated with the auxiliary piston, such spring being of such strength and so positioned that the' auxiliary piston may move the first-mentioned piston and the platen associated therewith through said spring to workpresenting position with respect to the other platen irrespective of the thickness of the work and still control the opening of said port always at the same point in its movement.

14. In a press, co-operat-ing platens for treating a piece of work, a piston for moving one of the platens toward the other, a cylinder enclosing said piston, an auxiliary piston for moving the first-mentioned piston, means arranged to move the auxiliary piston always the same predetermined distance, relative to said cylinder and spring means between the pistons tensioned to support the first-mentioned piston and the platen associated therewith, whereby with a given predetermined stroke of the auxiliary piston pieces of work of different thicknesses may be accommodated due to yielding of said spring means.

PAUL V. J. MERENDA.

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