US2792777A - Platen spacing control means - Google Patents

Description

May 21, 1957 c. USCHMANN 2,792,777

PLATEN SPACING CONTROL MEANS Fild June s, 1954 4 sheeneet 1 F l C?.V

PRESSURE T/l NK "lv/f. IIIIIIJ IIII " mm i] 25 I C UHT US C HMANN MaY 2l, 1957 c. uscHMANN 2,792,777

PLATEN SPACING CONTROL MEANS 4 Sheets-Sheet 2 Filed June 8, 1954 ,INVENTOR cuRr usc/#MANN May .21, 19.57 c. us'cHMANN 2,792,777

PLATEN sPAcING CONTROL. MEANS Filed June s, 1954 `4 sheetssheet 4 CONSTANT PRESSURE TANK CONS TA N T PRESSURE TANK CURT USCHMANN F/G. 7 Z

PLATEN SIACING CONTROL MEANS Curt Uschmann, Lebanon, Oreg.

Application June 8, 1954, Serial No. 435,166

16 Claims. (Cl. 100--200) This invention relates generally to platen spacing apparatus for multiple vertically moving platen type presses.

As is well understood in the art, in compressing loose ibrous materials such as are used in the manufacture of certain kinds of ber board, the loose material tends to be blown from between the platens by the air escaping therefrom if the platens are closed rapidly. The diiculty is less if the loose bl'ous material is initially about one inch or over in thickness but the problem becomes acute where it is less than an inch.

yWhile various arrangements have been heretofore devised and used to prevent such blowing of the material, yet they have been decient either functionally or structurally.

An object of my invention is to provide improved means that will enable overall closure of the press to be accomplished rapidly without blowing material out from between the platens or without otherwise disturbing the material.

A further object is to provide improved means for the foregoing purpose that are relatively simple in construction, operation and maintenance, that can be readily ap` plied to existing as well as originally manufactured presses, and that will function eiciently and effectively to prevent disturbance of material between the platens during the closing operation.

In accomplishing these and other objects I control' the closure of the gaps Ibetween the platens by initially suc` cessively moving the platensv in a closing direction until the spacing between all adjacent platens is somewhat greater than the portion of the gap taken up with the finally pressed material and then finally closing the remainders of all the gaps.

Other objects and advantages will be more apparent to those skilled in the art from the following'` description of the accompanying drawings in which:

Fig. 1 is a diagrammatic front elevation view of `a multiple platen press embodying my gap control invention with parts broken away, the front tension' columns being omitted for clarity. The press is'shown as fully open and also, for the sake of clarity, devoid of material to be pressed;

Fig. 2 is another diagrammatic view, simil-ar to Fig. 1`, but showing the platens after they" havebeen successively movedI to their parti-ally closed position; i

Fig. 3A is another similar' diagrammaticV view showing the platens completely closed; it' being` again understood that forclarity the material being pressed between the platens is omitted; p

Fig. 4 is a diagrammatic plan view of the press taken along the line 4 4 of Fig. l, showing the location of the pusher levers and control cylinders along the front and back of the platens;

Fig. 5 is an enlarged perspective oi ra pusher leverand of two platen spacing levers;`

Fig. 6 is a hydraulic circuit showingvr lil-ow` the levers of States Pattern:x

"icc

2 my invention are actuated to accomplish the obiects thereof;

Fig. 7 is a fragmentary front elevation view of a multiple platen press showing a modified form of my invention adapted to a platen press having a great many platens where the weight thereof and of the material therebetween is great;

Figs. S and 9 are fragmentary front elevation views of a multiple platen press showing an alternate form of my invention.

I show diagrammatically in Figs. l through 5 the upper part of a conventional multiple platen press having front and back columns 9 which support an upper stationary crosshead 10. A lower actuating platen 11 is vertically moved preferably by a hydraulically actuated ram 12 whose well known cylinder is not shown. Upper and lower heating and pressing platens l13 and 141` are respectively rigidly secured to upper crosshead 10 and to actuating platen 11 whilel 4other similar movable platens 15 are disposed intermediate said upper and lower platens.

It is, of course, to be understood that my gap control device may be applied, with equal electiveness, to platen presses having a greater or lesser number of platens than that shown. It is also to be understood that my invention doesV not dispense with, but is in addition not only to conventional platen Ispacing devices 33 for holding the platens fully spa-ced apart during the loading period but also to platen guides, ram cylinders, and other well known essentials and appurtenances of a platen press of this type. These latter have been generally omitted not only for the sake of clarity but because they do not form any part of my present invention. Also for the sake of clarity, material between the platens has been omitted from the drawings.

As shown in Figs. l to 5, I secure to each side of each platen a pair of platen spacing lever base plates 16 upon which pairs `of platen spacing levers 17 are pivotally mounted by pins 18. As shown in the enlarged perspective of Fig. 5, each of these platen spacing levers 17 has s fan arm 19, extending toward the center line of the press,

'and a foot 20 extending in the opposite direction. As shown in Figs. l to 3 the arms of all the levers are equal in length and the feet of all the levers are equal in length. The arm end of` each platen spacing lever is made suflciently heavy to -outweigh the foot end so that the greater weight of the arm tends to swing it downwardly. Hence, when not acted upon by sorne other force, levers 17 will remain in, or rotate by gravity to, a horizontal position, being stopped by feet 20 engaging the underside of a ledge 25. Thus when the press is open the foot will be in a horizontal position engaging the underside of a ledge 25.

On base plates 16 which are secured to lower platen 14, provide pivotal pusher levers 21 instead of the spacing levers 17. These pusher levers have arms 22 pivotally connected to lluid' jacks each including a piston 23 received in a hydraulic spacing control cylinder 24, this cylinder being pivotally mounted on lower actuating platen 111.

There are four spacing control cylinders, two on each` side of the press to actuate respectively the two sets of vertically aligned platen spacing and pushing levers.-

The remaining structure and hydraulic controls will be describedl in` connection with the following operation `ofl the press.

` Operation-With the press platens fully open and the platenv spacing levers 17 and pusher levers 21 in their horizontal position, the feet 20 bear upwardly against the underside of ledgesV 25 so that the levers are clear of the horizontal surface of the platens,` as shown' in Fig.` 1, and

thus do not interfere with loading the material to' be com pressed. After the material is loaded, uid pressurev from a suitable constant pressure source 26 is admitted into control cylinders 24 by manually opening a shut-0E valve 27, Fig. 6, so that pistons 23, Figs. 2 and 5, move upwardly to rotate-pusher levers 21 about their pivots 21 until the levers are inclined as much as 30 or 40 degrees from the horizontal. Main ram 12 is now moved upwardly to lift platen 14 and pusher lever 21 to cause rollers 28 of the pusher levers to engage and raise arms 19 of the platen spacing levers immediately above and thereby swing footed ends 2l) thereof downwardly until said feet rest upon the upper surface of stop ledges 2S of platen 1'5. This angular position of the levers is referred to herein as the gap control position. With platen spacing levers 17 of the platen 15 thus angularly disposed and held in such position by the constant pressure in control cylinders 24, the weight of platen 15 is carried by the four platen spacing levers 17 of this particular platen. Platen spacing levers 17 are so proportioned and positioned that in their gap control position their feet 20 extend below the lower surface of platen 15 to leave between platens 14 and 15 a small gap which, for convenience, is referred to herein as the one inch gap, representing a predetermined partially closed position or intermediate spaced relationship of the platens.

As ram 12 continues its upward stroke, Fig. 5, the rollers 29 of arms 19 successively engage the arms immediately above until they are all at their angular gap control position as shown in Fig. 2. In the case of platen spacing levers 17 of uppermost platen 13, which are not called upon to lii't this stationary platen or crosshead 10, the arms thereof are cut diagonally at 30 to engage a stationary stop 31 of said crosshead 10.

When all platen spacing levers have thus been rotated, the platens will be equally spaced apart with their one inc gap in their partially closed portions or intermediate spaced relationship and in a position ready to start compressing or pressing any material between the platens. The forego-ing closing of the platens to this gap position preferably is accomplished rapidly and allows trapped air or gases in the material to escape without any disturbance of the material.

The final step is the substantially simultaneous closure of the one inch gaps of all the platens. During this nal closing the actual compression of the material therein occurs. As the main ram 12 moves upwardly to `elect this compression, the ram force causes all of the control levers to be swung simultaneously toward their horizontal positions shown in Fig. 3 by the action of the stops and 31 and accordingly causes the platens to close simultaneously. This simultaneous action is controlled or effected by the action of the relief valves 32, Fig. 6, in allowing fluid in cylinders 24 to be expelled under a pressure which is initially setto sustain the weight of the platens when in their one inch gap control position. The relief valves thus constitute means for effecting or controlling nal closure ofthe platens. When the material has been cured in a usual manner, the ram moves downwardly, and if the pressure in cylinders 24 has not been removed the platens at lirst will all move apart substantially simultaneously until the spacer members have again assumed the positions of Fig. 2, and as the ram continues to descend the platens are successively deposited on their conventional platen holding devices diagrammatically indicated at 33, the platen spacing levers 17 resuming their horizontal positions as pressure on them is relieved. The treated material may then be removed from between the platens and new material inserted in the press spaces. l

During a cycle of the press the shut-off valve 27, Fig. 6, is initially opened whereby pressure from a suitable constant pressure source such as a tank 26 enters pusher lever control cylinders 24 through conduits 37 and raises pistons 23therein. When main press ram 12 has moved all the platens upwardly through the action of the platen spacing levers `17 to create the one inc gaps and thereafter continues the compression of the material, the pressure in control cylinders 24 which are rising with crosshead 11 will be at that value at which relief valves 32 are set. This pressure will be held during the period when fluid is discharged from the control cylinders through the relief valves into the tank 26. During this closing movement of the platens the gap control levers will move toward their horizontal position shown in Fig. 3 by reason of the greater force of the main ram. After the compression and curing operation of the material has been completed, the press is now opened by gravity in the usual manner by discharging iluid from the main ram cylinder, not shown. VAs the platens move downwardly, if the pressure in control cylinders 24 has been released 'the pusher arms and gap control levers will remain in their horizontal position and the platens will descend sequentially from the top down. The platens continue to open fully until they are supported on any conventional means such, for example, as the ladder 33. in this fully open position which may be, say, three inches, the platens are ready to receive another charge of material.

It is to be understood that opening and closing of shut-oil valve 27, as described above, is necessary only when manual operation of my gap control device is desired, as where the press is to be side loaded and hence vcannot be loaded unless the levers 21 are out of the way by being disposed in a horizontal position. In cases, however, where the tlevers cannot interfere with loading when in their gap control position as in end loading, automatic operation of the device may be desirable. This may be done by leaving shut-olf valve 27 open at all times, causing the levers at all times to be in their gap control position except for that period of time when the press is fully closed and the pressure in control cylinders 24 is overcome by the greater pressure exerted by the ram and the levers are forced to assume the horizontal position, but only so long as the ram force is applied, as shown in Fig. 3. When the ram is lowered from this position, uid from constant pressure tank 26 is allowed, through open valve 27, to llow again into control cylinders 24 and the levers return to their gap control position as the press begins to open, as described above.

While the mechanism described above is primarly for application to presses having a relatively small number of platens, yet, in presses having a large number, such as ten or more platens, the great weight of the platens and yof the material therebetween may become a factor to be reckoned with in insuring that the one inch gaps will be equal and that all platens will close simultaneously. As shown in Fig. 7, I achieve these objectives, and at the same time produce a more sensitive and smoother closing device in the following simple manner and without the use of any additional parts. Since all members of the arrangement of Fig. 7 are the same as those of the arrangement of Figs. l to 4, inclusive, the same reference numerals are used. However, instead of having the pivots 18 and 21 of the four vertical sets of levers 17 and 21 vertically aligned as in the Fig. 1 arrangement, I arrange the axes of the pivots 18 on opposite side of the press in upwardly converging lines 34, Fig. 7, that lean inwardly toward each other by only a small amount, such as, for example, 4 degrees. I also place the axes of rollers 28 and 29 along converging lines 36 which are offset say, 2% degrees, from the vertical. The overall length of the individual gap control or platen spacing levers is approximately the same from top to bottom but because of the ditferential in inclination of the roller and pivot axes, it will be seen that the foot 20 of each platen spacing lever 17 is longer than that of the next lower lever and that the arm 19 of each lever is shorter than that of the next lower lever. These angles of inclination also make a small lateral offset of perhaps a half inch between pivot centers of adjacent platens so that the levers are located approximately in vertical registry when they are.y in substantially horizontal positions. The angle of therleverswith reference to the horizontal progressively lessens from 40 degrees at the bottom to 30 degrees at the top.

It` is believed clear that by this arrangement pusher levers 21 will ultimately carry the combined load of all` the platens but the platen. spacing levers of any one platen will carry only the load of all the platens above that one platen. The progressive lengthening of feet and the shortening of the arms takes care of this weight support diierential in that the pivot `center of. each lever is` suliciently off center from the next pivot center below that no pressure lock or blocking lcan take place. Since the direction of force in closing the platens is straight upward and the pivot center of each lever is slightly oitset, the center distance from the pivot 18 to the roller 29 is gradually reduced and the distance of lift is also gradually reduced at the bottom platen where the pusher levers must move through, say, five inches to effect the same one inch gap that is done with only, say, a 2.1/2 inch lift at the uppermost platen. This feature makes it possible to compensate for the graduall loss of motion caused by the bearing clearance at each lever pivot. In other words, the arrangement compensates for the loss of motion due to the differential in weight or load strains applied against each lever pivot.

In the progressive angle modification of Fig. l the weight factor increases from platen to platen. This weight increases generally in proportion to the increase in eftective lengths of arms 19, and to the resulting increased angular movement requirement of the levers to ward the bottom of the press. The greater angular movement required for each lever than for the one next above it, compensating for the greater weight applied to such each lever than the next one abovel it, results in a truly smooth and even closing; of the one inch gaps. Should a. pressl having many platens be equipped with levers and pivots in exact vertical formation, as shown in Figs.` l to 4,` there would be a tendency for the lower platen gap to close lirst and then for the' next gaps to close successively due tothe non-compensated weight factor. Such actionI is permissible in some cases and in other more delicate applications the progression angle feature will serve best..

Figs. 8 and 9 show a modication of my gap control device for application to platen presses used for door and ne overlay manufacture where it is desirable to close the platen rapidly for that part of the gap that is not taken up. with material and then to compress the actual material by a comparatively slow stroke. In addition to any conventional' means similar, for example, to ladder 33\, .Fig.` 1`, for spacing and4 holding the .platens fully apart, I provide on opposite sides of the press a plurality of gap spacing ladders 70` having steps equally spaced apart a distance 71, each step being` equal to the sum of the thickness of one of the platens 72 and the extent of one of the one inch gaps 73 between platens. These gap ladders are slidably held against the platen edges by retaining members 74 secured by bolts 75 to said edges. A lower edge 76 of each of these retaining members 74 is positioned to engage and be supported by a ladder step during the initial closing of the press. To each of ladders 70 is secured an elongated cylinder 77 having a single pressure line connection 78 in the upper end thereof. A piston 79 designed for reciprocation within this cylinder is pivotally secured at its lower end to a movable supporting platen 80. With pressure from a constant pressure source 81 filling cylinders 77 and holding pistons 79 extended, movable supporting platen 80 is moved upwardly by a ram 82 causing platens 72 to be lifted from their conventional ladders or other supporting means and engaged successively by the steps of ladders '70. When topmost steps 83 of gap ladders 70 have reached topmost platen 72, which being secured to an immovable crosshead 84 marks the extreme upward movement of the ladders,r all platens will then have been equally spaced the one inc gap. As the main, ram 82 continues upwardly to close this one inch gap, ladders 7|!) and cylinders 77 now remain stationary and pistons 79 are, by the greater upward pressure force of the ram, forced to move into cylinders 77 to increase the pressure on the hydraulic duid therein. When such fluid pressure within the cylinders has reached the pressure at which relief valve 85 has been sett, the valve opens; and relieves the excess pressure of cylinders 77 into constant pressure tank 81. The lowering of the ram withdraws pistons 79 downward, but the pressure in such cylinders will be suicient to main tain the gap ladders 70 in their fully raised positions until the platens have been lowered to engage the ladder steps again, from the uppermost step downward. Further downward` movement of piston 79 allows gap ladders 10 to move downwardly by gravity controlled in their descent by the Huid pressure in cylinders 77. Platens 72 are maintained in their intermediate spaced relationship` by the ladders 70 until they are successively deposited, from the uppermost platen downwardly, on the conventional ladders or hangers of the. press. The pressed material may then be removed from between the platens.

From` the disclosure herein, it is seen that I have provided simple, reliable and elicient means for rapidly and successively closing the platens of a press of the type described to an intermediately spaced condition then closing them the rest of the way so as to prevent disturbance of material between the platens and more nearly to equalize the time' of pressing such material in all the press openings.

It will, of course, be understood by those skilled Ain the art: that Various changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as set forth in the appended claims.

l. Multiple platen press mechanism comprising means for moving a series of platens successively from open position toward'closed position, and means interrupting relative closing movement of such successive platens at a predetermined partially closed spacing independently of. any material to be pressed which is disposed between the platens, said interrupting means including iiuid pressure meanscontractable after all the platens of said series have reachedA such predetermined partially closed spacing to enable said moving means to complete the closing of the platens for pressing material therebetween.

2. The mechanism deiined in claim l, in which the contractable fluid pressure means includes a hydraulic jack.

3. The mechanism defined in claim 2, and means operable to effect discharge of liquid from the hydraulic jack toeffect contraction thereof automatically when the load on the iack exceeds apredetermined value.

4. The mechanism der'ined in claim l7 in which the means interrupting relative closing movement of the platens includes a member for each platen pivotally mounted solely on its platen for swinging about a substantially horizontal axis, each of said members including an arm extending to one side of its pivot for engagement by the arm of the member on the next lower platen as such platen approaches within the length of its arm, and each said member further including a foot extending to the opposite side of its pivot from its arm for engagement with such next lower platen to support the platen on which such member is mounted from such next lower platen for conjoint upward movement of such two platens.

5. The mechanism defined in claim 4, in which the contractable Huid pressure means is operable to hold the lowermost member with its arm projecting upwardly from its pivot in a predetermined position and is yieldable by pressure exerted on such arm by the arm next above 7 engaged with it to swing the lowermost member arm downward about its pivot for decreasing the spacing between the platens on which the members including such arms are mounted.

6. The mechanism defined in claim 5, in which the contractable fluid pressure means operable to hold the lowermost member with its arm projecting upwardly from its pivot includes a hydraulic jack.

7. The mechanism defined in claim 5, in which the contractable uid pressure means operable to hold the lowermost member with its arm projecting upward from its pivot is mounted on and reacts fromthe platen next lower than that on which such lowermost member is mounted.

8. The mechanism defined in claim 4, in which the arms of all the members are equal in length, the feet of all the members are equal in length, and the members are mounted on their respective platens to swing about axes which are all disposed in the same vertical plane.

9. The mechanism defined in claim 4, in which the members are approximately equal in length but the arm of each member is shorter than the arm of the next lower member and the foot of each member is longer than the foot of the next lower member, and the members are mounted on their respective platens to swing about axes which are all disposed substantially in a plane inclined from the vertical in a direction and to a degree such as to locate the members approximately in vertical registry when such members are in substantially horizontal positions.

p l0. The mechanism dened in claim l, in which the means interrupting relative closing movement of the platens includes a ladder mounted for vertical movement by the first means and having steps respectively engageable sequentially with successively upper platens.

ll. The mechanism defined in claim l0, in which the contractable means is incorporated in means mounting the ladder to enable the first means to move relative to the ladder for moving the platens closer together than when they are engaged with the ladder steps.

12. The mechanism defined in claim 11, in which the contractable fluid pressure means includes a hydraulic jack.

13. The mechanism defined in claim 12, and means operable to elect discharge of liquid from the hydraulic jack to effect contraction thereof automatically when the load on the jack exceeds a predetermined value.

14. Multiple platen press mechanism comprising means for lifting the bottom platen of a series of platens to transmit a lifting force therefrom to the platens above it in closing the press from open condition, spacer means successively interengageable between each of a plurality of said platens and the next higher platen, during upward movement of the bottom platen, to lift each such next higher platen in a predetermined intermediate spaced relationship relative to the next lower platen as such next lower platen is lifted, and means for restraining upward movement of the uppermost platen of the series, said spacer means including yieldable fluid pressure thrust means movable by upward movement of the bottom platen to contract the eifective vertical length of said spacer means upon continued upward movement of said bottom platen, enabling the platens to be moved closer together than when in such intermediate spaced relationship established by said spacer means.

15. Multiple platen press mechanism comprising means for lifting the bottom platen of a series of platens, and spacer means independent of any material to be pressed which is disposed between the platens, disengaged from the platens when the platens are in open position and engageable successively with the platens of such series from the bottom platen to the top platen, as the bottom platen is lifted, to transmit lifting force by said spacer meansV from lower platens of such series to higher platens of such series when successive lower platens respectively reach a predetermined closely spaced relationship to the next higher platen, and said spacer means being contractable to enable said first means to move the platens closer together by lifting force transmitted from one platen to the next higher platen by material to be pressed which is disposed between the platens when the uppermost platen of the series has been engaged by said spacer means.

16. Multiple platen press mechanism comprising means for lifting the bottom platen of a series of platens, and spacer means independent of any material to be pressed which is disposed between the platens, disengaged from the platens when the platens are in open position and engageable successively with the platens of such series from the bottom platen to the top platen, as the bottom platen is lifted, to transmit lifting force by said spacer means from lower platens of such series to higher platens of such series when successive lower platens respectively reach a predetermined closely spaced relationship to the next higher platen, and said irst means being operable to disengage the platens from said spacer means and move the platens closer together by lifting force transmitted from one platen to the next higher platen by material to be pressed which is disposed between the platens when the uppermost platen of the series has been engaged by said spacer means.

References Cited in the le of this patent UNITED STATES PATENTS 569,920 Hubbell Oct. 20, 1896 1,870,499 Ernst Aug. 9, 1932 2,479,988 Carver July 1, 1941 2,586,474 Moore Feb. 19, 1952 FOREIGN PATENTS 674,898 Great Britain July 2, 1952

Images