US3050777A

US3050777A - Multi-platen press

Info

Publication number: US3050777A
Application number: US6188A
Authority: US
Inventors: Siempelkamp Eugen
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-02-05
Filing date: 1960-02-02
Publication date: 1962-08-28
Anticipated expiration: 1979-08-28

Description

Aug. 28, 1962 E. SIEMPELKAMP MULTI-MATEN PRESS 4 Sheets-Sheet 1 Filed Feb. 2, 1960 Aug. 28, 1962 E. SIEMPELKAMP 3,050,777

MULTI-PLATEN PRESS Filed Feb. 2, 1960 4 Sheets-Sheet 2 .7n ven/or:

Eugen, SiemPe kamp Aug. 28, 1962 E. SIEMPELKAMP MULTI-PLATEN PRESS 4 Sheets-Sheet 3 Filed Feb. 2, 1960 Jnvemor: Eugen Siem/oe/fam/o BY wf@ Agen-l:

Aug 28, 1962 Filed Feb 2. 1960 E. SIEMPELKAMP MULTI-PLATEN PRESS 4 Sheets-Sheet 4 ilite 3,959,777' MULTl-PLATEN PRESS Eugen Siempelkamp, Hohenzoliernstr. 69, Krefeld, Germany Filed Feb. 2, 196i), Ser. No. 6,183 Claims priority, application Germany Feb. 5, 1959 9 Claims. tCl. it-le) My present invention relates to a multi-platen press and, more particularly, to platen-spacing means for such presses.

Multi-platen presses, and primarily those employed for the heated compression and curing of cellulose-liber sheets (eg. iiberboard), have been provided heretofore with lazy-tongs or similar mechanisms adapted to maintain the spacing between the several platens during the closing of the press. These lever linkages do not, however, compensate etlectively for the omission of sheets as a result or" a faulty press-charging operation or for the varying thicknesses of the sheets. Thus, the major compacting force of a hydraulic press bed is often applied only to a few of the charged sheets, or unequally to the entire charge.

lt is, therefore, the general object of my invention to provide a multi-platen press ,adapted to obviate the abovementioned disadvantages.

A more specific object of the invention is to provide improved platen-spacing means for multi-platen presses.

According to a feature of my invention, the sheet-'supporting platens of a multi-platen press are elevated concurrently with the elevation of the bed plate, but at different rates corresponding to the distance each platen must be vertically displaced to reach the point at which compression of the charge between the -bed plate and the head plate of the press commences. Generally speaking, the lowest platen (nearest the bed plate) will require the greatest displacement while the uppermost platen (nearest the head plate) will require the least. Upon reaching the point at which pressure is applied by the bed plate, or at least the point in the closing of the press at which such pressure would normally commence in the presence of .a full charge, the platen-spacing apparatus is rendered inoperative, in accordance with the invention, so that no mechanical strains will develop from any unequal spacings as caused, for example, by the absence of one or more rough sheets between the platens or from differences in the thicknesses of the inserted sheets. Advantageously, the platen-spacing apparatus may subsequently be caused to function again for the gradual lowering of the platens after compaction or at some other point in the press cycle to assist in readying the press for the next charge.

According to another feature of the invention, the platens are raised and lowered by individual mechanical links preferably in the form of cables secured to a suitable transmission mernber, such .as a step pulley. The cables attached to the lowest platens may then engage the largest-diameter steps of the pulleys while the successively higher platens are connected with respective smaller-diameter steps. Thus, upon rotation of the pulleys either independently of or in response to the elevation of the bed plate, the step pulleys taire up the cables in proportion to the required vertical displacement of each platen, thereby closing the press gradually and smoothly and without requiring the bed plate or the lower platens to support upper, unloaded platens. Advantageously, the rotation of the pulleys may be coupled to the movement of a hydraulically elevatable structure, eg. the bed plate itself, via tractive members and suitable direction-changing means whereby the closure stroke of the bed plate prior to compression is utilized to operate the spacing apparatus. The latter may then be ren- 'l'i Patented Aug. 28, 1962 dered inoperative, for the purpose mentioned above, by slackening the tractive members.

According to a more speciiic feature of the invention, the spacing apparatus is uncoupled from the drive means therefor by halting the rise of the elevatable structure accompanying the closing movement of the bed plate while permitting the latter to continue its stroke, thereby compressing the sheets while concurrently slackening the cables. The spacing apparatus may also be engaged or disengaged by means of electrical and hydraulic control circuits actuated directly by the motion of the bed plate.

The above and other objects, features and advantages of my present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. l is a somewhat schematic front-elevational view, with parts broken away and in section, of a multi-platen press according to the invention;

PEG. 2 is a view, similar to FIG. l, of a second embodiment of the invention;

FlG. 3 is a side-elevational view, with parts broken awa of the embodiment of FlG. 2; and

FIG. 4 is a schematic circuit diagram of this embodiment.

ln FlG. l I show a multi-platen press in the open condition thereof, comprising a generally rectangular frame l. A bed plate 3, vertically displaceable by a hydraulic piston 2b received in cylinder 2a, is provided between the front and rear members of frame l to compress roughly formed cellulose-liber sheets 2l, carried on a plurality of vertically spaced platens 4, against a head plate 2Q. The platens 4iare each supported by four cables epending from step pulleys 5 journaled at the tour upper corners of the press frame. The pulleys 5 are provided with steps of progressively increasing diameter, respectively proportional to the requisite displacement of each platen during the closing of the press. The uppermost platen is therefore connected to the smallestdiameter step while the cables 6 of the lowest platen are secured to the largest-diameter step. Advantageously, the cables are joined to the platens 4 at lugs Z2, dimensioned and staggered to maintain the cables in plumb despite the dillerent radii and axial spacing of the steps. Each pulley 5 is driven by a cable 7 secured to the driving step thereof and partly wound therearound. The cables 7 are passed about direction-changing and tensioning pulleys 8 and connected to bed plate 3 at lugs 23. Each pulley 8, at one of the four lower corners of the press frame l, is supported on a vertically displaceable piston 9 received in a cylinder 1d. Each pulley 5 is also provided with a ring of ratchet teeth 2 engageable by a pawl il. The latter may be removed from engagement with the ratchet teeth by .a release mechanism l2, such as a solenoid, actuatable via an electric circuit arrangement comprising a source of current Z5 and a pressure-sensitive switch schematically indicated .at 26. The master compression cylinder 2a is supplied with fluid from a reservoir 27 via a pump 28, a pressure valve 29 and a distributing valve 33, while the cylinders 14 are supplied with fluid from the pump via valve 29.

In operation, upon the charging of the press with the sheets 21, the handle of distributing valve 33 is actuated to permit a ow of fluid under pressure from' the pump 2S through valve `29 and by way of conduits 32Y and 3'4, to the cylinder 2a, thereby raising piston 2b and bed plate 3. Simultaneously, 4fluid ows from the pressure main 35 through valve 29 and a lbore provided in the armature 29' thereof to conduit 3G. From this conduit, uid enters the cylinders 14 above the head of pistons 9, thereby locking these pistons in the position shown in FIG. 1 to tension the cables 7. As bed plate 3 rises of pulleys v8 `to permit the Y similarly provided Ving valve 40 nected in a circuit including an `55b lie in series withV VV.previously described, and the 'is inserted in to close the press,Y the vertical movement of the plate isA V2a is transmitted to pressure valveV 29 and causes a down-Y ward displacement of the diaphragm 29a thereof along with the plunger 29' secured thereto. The bore of this armature then becomes aligned with that of return tube 36 whereby uid can return from cylinders 14 through conduit'31 into the reservoir 27. Piston 9, no longer held against vertical displacement by -uid pressure, rises under the tension of cable 7 to slacken the latter so that further elevation of the bed plate 3 Iwill not transmit motion to the pulleys 5 which are locked against reverse movement by the pawls 11 engaging -appropriate teeth of their ratchet ringsY 24; When the hydraulic pressure attains a predetermined-maximum, switch 26, linked with valve 29 by a tube 26', is tripped to activatesolenoids 12, therebyV disengaging the pawls 11 ,from toothed rings 24 and Afreeing the pulleys 5 for Vreverse rotation. After a curing period at maximum pressure, reversed to exert downward pressure upon piston 2b Yvia a tube 34"'and to drain the fluid from the master cylinder 2a via tube 37 while bypassing a limited quantity of fluid from the pres-sure'valve 29 to Vthe reservoir through

tubes

32 and 37. The pressure in the valve thus drops, the diaphragm' 29a thereupon raising the plunger 29' to its original position to re-open the uidpath to the cylinders 14; this again tensions the cables 7 upon the descent bed plate 3 to lower the platens gradually and at different rates. As the bed plate 3 comes to rest in its bottom position, switch 26' and, therefore, solenoids i12. to normal, thus permitting the pawls 11 to re-engage the teeth of ratchets 24 as the bed plate 3 rises for another press cycle.

Y In FIGS. 2 and 3 I illustrate another embodiment of the invention'wherein the bed plate 3 is adapted to compress a plurality of sheets 21 carried by the platens 4 against `a head plate as described hereinabove. The platens are again supported from four step pulleys 5 by cables 6 secured to the platens 4 at bars 22. In the present embodiment, however, the tractive elements 7, adapted to drive the pulleys 5, pass under idler pulleys 38 not displaceablev in a vertical direction. The elements 7 are ioined to a pair of `yokes 17 (one ofwhich is shown) extending at least partially beneath and transverse to the bed plate 3, these yokes being elevatable by a pairV of hydraulic cylinders 16b whose pistons 16a bear thereon from below. of master cylinders 2a. ment for the present embodiment is further illustrated in FIG. 4.' Each platen 4 and the'head plate 20 is provided witheone of a plurality of series-connected switches 41a to l41h which are closed by the engagement of their armatures with the next-lower platen 4 or with the bed plate 3. A second set of switches 37a to 37h, closable directly by platens 4 or bed plate 3 and connected in parallel, are on each platen 4 and the head plate 20.

A normally closed limit switch k45 is mounted on the base of the press so as to be open-circuited upon the downstroke of yoke 17 by a stud 43'carried thereon. The parallel combination of switches. 37a to 37h is connected in series with the drive Aand with a source 43 of electric current, while the series-connected switches 41a to 41h are conelectromagnetic holding relay 55 andthe battery 43. 'Ihe relay contacts 55a, parallel-connected `solenoids 12, battery'43, while switch 45 the holding circuit of relay 55. l Y Y v valve 33 maybe downward movement of the the reduced pressure in the valve29 restores Bed plate 3 is also carried on pistons 27.1:V The electrical circuit arrange-j motor `44 of a hydraulic distribut? In operation, hydraulic uid from reservoir 27 is forced by pump 28 through a transmission tube 50 to the master cylinders 2a Ywhile l1617 via tube 52, Ythereby raising the yokes 17 and the bed 3. It will be apparent that the owvof iluid may be so regulated as to permit the yokes -to raise the bed plate 3 or to cause the substantially simultaneous elevation of both yokes and the bed plate. The press thus 'closes until one or more of the parallel switchesV 37a to 37hroperate.

Thereby an electrical circuit is closed to drive motor 44 which Yadjusts the distributing flow of fluid to cylinders 16b while continuing the under increased pressure to master cylinders 2q. YThe upward motion of the yokes 17 thus ceases whereas the bed plate 3 commences its compression stroke, thereby slackening the cables 6 and.7 to disengage the spacer apparatus. At the conclusion of the compression stage, i.e. when all the sheets have been compressed to their predetermined thicknesses, the series-connected switchesl 41a to 41hrclose to complete a circuit to the winding of relayV 55, thereby closing the

contacts

55a, 55b and op-V erating the solenoids 12 to withdraw the pawlskll from `engagement with their ratchet rings Yas described with f reference to the preceding embodiment. After -a predetermined curing timehas elapsed, the motor 44 in its continuing operation blocks the fluid ow to cylinders' 2a vand opens a return path from the latter to the reservoir y27 via return tube 56. The bed plate thus commences to lower, entraining in the'latter part of its descent the yokes 17 to re-activate the spacer mechanism. The distributing valve 40 may be designed to introduce uid at this time to the tops of cylinders 1'6b and 2a via

tubes

53 and 51, respectively, press opens. As the yokes 17 and the bed plate 3 attain the kfully opened position normally closedY switch 45 toY deactivate the relay 55,

Y 4thereby releasing pawls 11 and restoring the spacer as- Abutments 57 (only one shown) on the frame 1 of the Y Y press serve las safety stops for the yokesA 17 to insure a Y slackening of the cables even upon failure of the switching Y circuit 37a tov 37h. IIn cases where major differences in sheet thickness and partialloading of the press are no problem, such abutments (positioned, desired, atY a somewhat lower location on the frame) may also be used in lieu. of such switching circuit as means for deactivating the spacing apparatus Iat a predetermined point in the 'ascent of the bed plate 3.V Under such circumsoY stances it would also be possible to dispense with `all but one of the switches 37a to 37h and to mount the remain- Y ing switch on the frame 1 for actuation by Vone of 'the i' 'yokes 17 (FIG. 2) or by the bed plate V3fV (FIG. l or 2) as the latter reaches the point at which slackening of the cables is to occur. These and other modications, which will beY readily apparent to persons skilled inthe art, are intended to be included within the spirt and scope Yof the` invention 'except as further limited by the appended claims. Y

I claim: Y

1. A multi-platen press for the compaction of sheet materials, comprising ya frame; a pluralityof vertically spaced sheet-supporting platens held on sa-id trame for vertical movement; a xed stop on said ame aboveV said platens; plunger means below said platensoperable to act upon the -lowermost platen in a manner pressing all of said platens and the intervening sheets against oneV another and said stop; operating'means for raising said plunger means; transmission means coupled with said plunger means for raising said platens simultaneously withY said plunger means -at rates decreasing progressively from the lowermost to the uppermost platen whereby the separations between said platens concurrently decrease uponY the rise of said plunger means, said transmission means f comprising a stepped pulley, Va set of cables passing a part of the fluid enters the cylinders Y valve 40 to shut oi theY iowY to increase the rate at which the Y of the press, plunger 43 tripsthe Y around respective stops of said pulley and lanchored to respective platens, and coupling means including a further cable releasably interconnecting said plunger means and said pulley for rotating the latter upon a rise of the former; tensioning means bearing upon said further cable in a rst direction tending to raise said platens through said transmission means for maintaining the connection between said pulley and said plunger means during at least part of the rise of sm'd plunger means; and automatic means coupled with said tensioning means and controlled by said operating means for temporarily inactivating said coupling means at an intermediate point in the rise oi' said plunger means by slackening said further cable through a displacement of said tensioning means in a second direction opposite said iirst direction.

2. A press according to claim l wherein said operating means comprises a hydraulic system.

3. A press according to claim 2 lwherein said automatic means is provided with an Vactuating element responsive to a rise in the hydraulic pressure of said system due to beginning compaction of at least one of said sheets.

4. A press according Ytoclam 1, further comprising switch means controlled by at least one of said platens for operating said automatic means.

5. A press according to claim 1 wherein said tensioning means comprises a deiiecting roller engaged by said further cable and said automatic -means includes hydraulically displaceable support means for said deecting roller.

6. A press according to claim 1 wherein said plunger means comprises a bed plate, said tensioning means comprising a follower member upwardly displaceable by said operating means along with said bed plate during a portion of the ascent of the latter, said further cable being anchored to said follower member.

7. A press according to claim 6 wherein said follower member comprises a yoke embracing said bed plate from below in a lower position of said bed plate, said automatic means land said operating means respectively including first and second hydraulic systems for respectively raising said yoke and said bed plate, said tensioning means vfurther including stop means for inactivating said first hydraulic system.

8. A press acccording to claim 1, further comprising check means for locking said stepped pulley against reverse rotation and release means for de-activating said check means substantially upon attainment of its highest point by said plunger means.

9. A press according to claim 8 wherein said check means comprises a set of ratchet teeth on said pulley and pawl means yengageable with said ratchet teeth, said release means including an electromagnetic device for retracting said pawl means from said ratchet teeth.

References Cited in the file of this patent UNITED STATES PATENTS 2,941,249 Rogers June 2l, 1960