US2172003A - Platen press - Google Patents

Description

Sept' 5, 1939 R. w. STANLEY E-r AL 2,172,003

P LATEN PRESS med May 2o, 1957 s sheets-sheet 1 R. w. STANLEY Er A1. 2,172,003

Sept. 5, 1939.

' PLATEN PRESS Filed May 2o, 1937 3 Sheets-Sheet 2 T P- f1 E E I I T 1` Sept 5, 1939- R. w. STANLEY ET Al. v 2,172,003

PLATEN PREss Filed May 20, 1937 3 Sheets-Sheet 3 Patented Sept. 5, `1939 PATENT- MOFFICE PLA'rEN PRESS Richard W. JStanley and Ericsson Il. Merrlt Lockport, N. Y.,' assignors to Merritt Engineering and Sales Co., Inc., Lockport, N.

poration of New York Application May 20, 1937, Serial No. 143,734 Y 2 Claims. (Cl. 144-281) The present invention relates to presses, and more particularly an improved single or multiple opening hot plate press for the manufacture of plywood' and similar products requiring the 5 simultaneous applicationv of heat and pressure to sheet materials.

4The principal objective is to provide a new form of hot plate press in which sheets of veneer,

or lumber .cores and/ face veneer, may be adhesively united by heat and pressure with a new degree of uniformity of treatment, the design being such'also that thehmachine can operate at greatly increased speedA and with proportion*- ately increased output. 1 Obviously this press '1B may belused for performing vany voperation in.

which a rapidl application of pressure, or heat .'and pressure is desirable. This press may of cours'ex also be used with unheated plates if desired. The present improved construction for securing these results also obtains a variety of otherincidental advantages the nature of which `will be readily understood from the subsequent detaileddescription of the machine.

To the accomplishment of the foregoing andl related ends, the invention, then comprises the features hereinafter fully described, and par' ticularly pointed out in the claims, the followdescription setting forth in detail certain illustrative embodiments of the invention, these beingindicative however, of. but a few of the various ways, in which the principle of the invention may be employed. `In presses of this character the custom for tle most'part; is to so design the press that the ad load is also the means for opening and closing the press. ,In the. present design the respective functions of opening and closing and that of pressing have been divorced from each other withl an appropriate provision of separate mechanical means for performing these two distinct functions. In the present construction ,openind and closing is accomplished by mechanical means, whilevthe application of working pr re which follows closing, is accomplislied byJiluid pressure applied either by hy draulic means but preferably applied by pneumatic means.` l

The present application supplements. two

' a previous applications, ser. No. 744,132, E. H.

Merritt,.now issued as Patent No. 2,148,704, dated February 28,;1939. and Ser. No. 118,505, RaW. Stanley, rthe present construction beinga development based in part` upon `the earlier disclosures, Theseprior applications. described the means for' applying the working pressure to the use of a diaphragm pressure element which is also used in the present construction, The features of balancing the weight of the moving parts and of differential movement of the plates in an accordion-like action, are new elements 5 with which the present application is concerned, In the earlier applications also, the operation of the diaphragm was by means of a liquid only,

'while in the present design the improvement has been added optionally operating 4the diaphragm lilr by the elastic medium 'of air or a gas, this feature cooperating with the accordion'movement. lI n addition to the mechanical features and combinations. of machine elements comprising the present hot plate press construction, the 15 various new features and functions provided thereby, afford a means for the operation of a new process and treatment in laminating panels and plywood. This new process forms the subject of a separate application filed simulta- 2o neously with the present. case.

In the annexed drawings l Fig. 1 is a side elevational view of an embbdiment of the invention; Fig. 2 is a diagrammatic plan view' thereof showing the arrange- 25 ment of the gearing on the top of the press; Fig. 3 is an end elevation .of the construction shown in Fig. 1;' Fig; 44 is an enlarged sectional detail of the gear-driven nut; Fig. 5 is a diagrammatic elevational view illustrating the se- 30 quence of pick-up in the closing of a platen press of usual form; Fig. 6 is a similar showing of the pick-up by a press in accordance with the pres-v ent invention, and Fig. -7 is a transverse crosssectional view of the press, taken on the line lpassing through the heady B are threaded for a considerable distance and engage nuts F mounted on the head such that when turned theycause the head to -move up or downv lon the threaded rods.- .As seen in Flg. 4, this mgunting' 50 may comprise a bushing F1 secured to the head,

and. enclosing a rotatable sleeve `F2 -whose upper end is provided with gear teeth Fa, and is secured by suitable means to4 the screw threaded nut portion kF4 which turns on the. threaded rod. 55

4The toothed portionsFa, constituting pinions,

ing, such as F7, Fa, Fo. F1o from a motor m conveniently located on the press-head. Rotation of the motor shaft, thus through the gearing Ffa to Fs rotates the nuts Fin appropriatediretion. I

as desired, depending upon whether the press is to be closed or -is to be opened.

.If this machine were to, operate as a conventional screw press the base would restdirectly upon the foundationv and power means would be provided adequate notV only to close the press but to exert the required maximum pressure upon the' work. However, in 'the present invention, the

screw press action is limited in its function to theJ mere work 'of bringing the plates into mutual ',contact, while working pressure is supplied subsequently by separate means, preferably, for emample, by`av diaphragm as described in said 'pending' applications, Ser. No. 744,132 now issued hndSer. No. 118,505.

as Patent N0. 2,148,704, dated February 28', 1939,

Since one of the principal objects of the present -inventio'n is to facilitate using maximum open?,

ing and closing speed, means have been provided for balancing the weight ofthe necessarily m -L sive and heavy moving parts against each, other. The head weight'ls balanced against the weight of the base and strain rods, and half ther-plates 'are also balanced against 'the other half. To acf` complish this the'base A does not restupo'n the foundation but is suspended in very much the same manner as a scale platform. The foundation members carrying the entire weight of the press are two non-revolving shafts G, one at each end of thepress, and theends of each shaft are keyed to blocks H which, in turn, are bolted to the foundation', which may be of concrete for example.

. Upon each shaft are mounted two spaced rocker arms I carrying pivot 'pins J, equally spaced on "opposite sides of' its center. The pivot pins in the inwardly-extending ends of the rocker arms carry rollers K which bear above and below on shoulders In on thebase. These-shoulders are faced with hardenedsteel plates to reduce wear. Th pivot pins inthe outwardly-extending ends of the rocker arms. carry 'connecting' arms M pivoted likewise attheir upper ends in ears N welded or otherwise secured to the head B.

`Disregarding for the moment thethreaded nut connection 'of the hea`d to the strain rods, it is eeen that the weigh#l of the together with:

the eaghed strain rods, 1s carried by the rollers operating elements, is transmittedl through the connecting rods M tothe pivot pins in' the outer endspf the rocker arms I. =Thus, if it'is`assumed that the weight of the baseA and head are equal they are in balance with each other. To insure equality, the head', which 1s naturally someehat' lig/liter` glue to the strain rods being carried'l by the base,\is provided 'with a hollow space into, which can be poured suiiicient concrete -to equalize the weightwith the base.C However, because ofthe threaded connection of the strain rods to K, while the weightf the head, together with its pleted. -f

Consequentlywhen the nuts F- are revolved in a direction to cause the head to descend on the rods C, the connecting rods M depress-the rocier arms I at their outer ends and raise the rollers K pivotedtto 'their inner ends. Therefore, as the head descends the base ascends an equal disftance and at the same speed, and although the head and the base are moving in opposite direcrtions they are moving inI balance.

The result of thisrelationship is thatsince head and base are jxnoving at the same time in "opposite directions toward a common middle point, the time of :closing has been reduced by one half without having increased the rate of .travel of the head or Abasernembers beyond that commonly used in a press wherein only one of i movement of Vthese* massive parts yis-their inertia, and the very desirable result has been attained Aof reducing the power required to open and close these members travel. Furthermorel since head y and base are balanced the only limitation to quick i the press to thelowest termswith a simultaneous s 50 pei` cent decrease in the time interval required for the opening andclosing movement. y -In,.the conventional type 'of hot pressthe plates' are suspended from the press? head,/ usually byv Ahanger. rods in such -a way that when the press is open there is an equaloperging between each pair ci adjacent plates. This open space or daylight;

as'it is commonly called, ordinarily'varies 'from one to four inches according tothe kind of work the press is designed to handle. If in the press` here shown, the plates werehung from the head inf the usual manner and the pressV wasclosed from below by the upward movement of a ram `which raised the base towards the head, the closing up'of the daylight spaces would be a suc'- lcessive movement starting with the lowest space Y and ending with the uppermost one. The base,

, v :1 -.v In contrastto such type of closing, the #resent invention involves adiilere'ntial closing movement shown. I

1n other words, would ummetehf plea-.up en diej@ asis illustrated by Fig. 6.v In this'difierentiai movement it will be seen that all the plates are in motion from beginning to end, thatf'allf spaces begin to close at the same time, are alhnally closed at the same instant',-and are at ,alltimes open to the same extent before closing is com Referringto the and 2, it is seen Vthat the strain rodsC at op-r posite ends of the. press vare rigidly connected at, lthe )ipper end byA a yoke l. Mounted in these yokes are two shafts-2. Thus the upperen'ds press` assembly as ir Figs. i 55 of the strain rods are held'together in ai'iframe-oo Y in much the same way as they l are held together .at 4,their lower ends by the base. The strain rods.

jtherefore, can act as rigid guides for movementsi of the head. At eaclhend of the press a'painof arms 13 is keyed to shafts 2, and there are con-- 05 nectingl rods 4` with pivots at [which connect their outer extremities with-ears l'bonded to the Y.

' head B. At equal intervals along the arm 3 be-` 'tween the shaft .z ,endtheoonneouhg rod pivot 8 are attached hanger rods i of varying length, 7o

each plate in the press being Ystampi-ted by a group of four of these rods all ofen equal length which iis adjusted to provide the desired spacing or maximum'daylight between the Aplates when pansion or contraction of the diaphragm. Thispivot connection with the arm 3 is provided with a coil spring 'l to provide a cushion for taking up any inequalities in the thickness of the panel assemblies in the several openings and thus avoid Vaccidental stresses which otherwise might .cause breakage.

The arms 3 are shown at the middle point of v stationary the rocking movement of arm 3 wouldv cause the plate hanger rods 6 to move vertically various distances depending upon -the distance veach rod is pivoted from the center of shaft 2. 'I'his in turn would cause the plates toV move vertically variousv distances depending'upon the position of the point of attachment of their particular hanger rods. The lowesthung plate would be supported by rods pivoted farthest from shafts 2 and would move the greatest distance, while the top hung plate supported by rods pivoted closest to the shaft 2 would travel-the least distance. However, yoke l is not stationary since it is attached to the strain rods, which, in turn, are attached -to the movable. base. It is seen that when the head descends the base ascends and carries the yokes I and shafts 2 with it. The arm 3 atthe middle point of its length is therefore a dead center and one end of the arm moves up wh'ile the other endA moves down anequal distance. Transferring this movement of'the arms 3 to the plates in the press, the movement'is'likewise towards a' neutral center point, the topmost plate moving downward and the bottom plate moving upward while the middle plate in the group remains stationary shown in Fig. 6 at center line XY.

In connection with the foregoing description of theA means for giving the plates an accordion movement during the opening and closing, it is particularly pointed out that the maximum opening between the plates is adjustable at will since it depends on the amount of movement of head andbase, which can be limited at any.; desired travel short of the full movement. If the maximum space or daylight between the plates is three inches when head and base are separated the' maximum` distance from -each other, the space`between the plates will be `one and one-'half' inches when head and'base are at .the middlepoint of their approach. Under operating conditions if it is assumed that the thickness of panels to be pressed runs fromv one-sixteenth of an inch to two inches, it is obvious that a `maximum opening' of Athree inches between plates is not n.1--v ways necessary. Obviously also it is needless to provide more thanabout a one-inch opening when operating on panels only one-sixteenth.

vinch thick. Therefore it is desirable to limit the movement of head and base in conformityv with4 the space requirement as regards opening for the work in hand. This preventsv unnecessary travel in opening and closing and saves both time 'and power. With the present design this adjustment of the daylight spaces to thework in hand becomes merely a matter of stopping the actuating motor at the right time. Automatic means for accomplishing this will be described later.

' For applyingworking'pressure after the press is 'closed by, mechanical means.` use" lsmade ofV diaphragm d incorporated `in a, retainer-"with la. cover lfree to move up and downwithfthe exfis shown and `described in our co-pending applications 744,132'and 118,505. In-the press here shown the expansion medium in the diaphragm may be either air or aliquid. One purpose ofv the press design here shown is as already stated to secure the maximum speed of opening and closing, hence pneumatic means for applying the operating pressure is preferred. Increased speed of movement means increased shock when the plates come together on the panels lying in the open spaces. 1n co-pnding application Ser. No. 118,505 provision is described for introducing a small amount of liquid in the diaphragm` just before the plates completelyclose u'pon the panels. The purpose of this is to facilitate the opening of the press. When the press is pneumatically operated, the introduction of a small' amount of air in the diaphragm performs this function as well as an additional one.

vAir is' elastic and compressiblewhile liquids are rigid and incompressible. Consequently air in the diaphragm as compared to liquid, converts the latter into a cushion which absorbs and dissipates shock occurringwhen the plates make vcontact at the end of a relatively rapid closing movement. Furthermore, compressed air isa quick acting medium, and its isecooperates with and supplements quick opening and closing movement by providing also quick application and withdrawal of high working pressure. To this must also be added the advantage derived from the cushioning effect of the pneumaticshock absorber permitting the use of high closing speed.-

While a diaphragm'andparticularly a pneumatic diaphragm, is preferred as a means of applying working pressure, the use of other pres-` sure means is not excluded. With the balanced A- accordion movement of the press plates which provides for simultaneous closingof the various openings with the head and base both approaching a commoncentre and while the moving parts involved are maintained in a condition of balance, it is obvious that manyv advantages will "be secured with almost any apparatus `for applying Aworking pressure. For example with a hydraulic ram, only working pressure has to be applied by the ram and consequently only slight 'ram movement is needed permitting quick pressing. However, this lacks the very desirable cushioning effect supplied by .the pneumatic diaphragm. Y

y.To co-relate'the mechanical opening and closing with high. pressur'epneumaticfor hydraulic operation, automatic electric stops and controls are desirably provided, essentially the same as shown inca-pending application Ser. No. 118,505,l

and notdrequiring detailed showing here. l

In operation, the cycle starts'withthe press open, the amount `of daylight between plates having been determined by the thickness of panels to be pressed, and the automatic stop having been set to discontinue the opening movement atthe end of eachcycle after the predetermined amount of travel has occurred. The

panel assemblies are loaded into .the individual.

press openings, either singly or simultaneously by a loading device, whereupon the operator presses a control button which venergizes the motor and 'causes revolution ofv the nuts', which bring the' base and head towardseach other until the spaces are fully-closed. 'Just before the instant when the motorl is automaticallyfcut out and the closing movement ends, the air valve 1S' animatie@ were@ by' decirle @mm1-.1 i5

aimons and a .small 'amount of 'admitted to the tion of. final pressure, but also assures an easy diaphragm'which becomes partly iniiated and acts as a cushionto take up the shock ofmechanand even shockless .contact when nal pressure is applied.

ical closing. Almost instantly thereafter full The use of mechanical means for opening and 5 working pneumatic ,pressure `is built up within closing is fast as compared to hydraulic means 5 the diaphragm, and the panels are then kept and,- furthermore, requires lesspower to operate.A

A4under-A pressure until theaactind of the heat in Balancing theV weight of .the heavy massive the plates has set up the adhesive and the members -in motion reduces the power cpu.-

bondingis inished.4 If the pressing is repetition sumption. l l0 manufacture-of the same umts so-that the same f Movement of balanced weight contributes to' lo press-timers repeated with each press load, autohigher closing speed. l m'atic means -rnay be provided for timing, press- Since the means employed` to balance weight i ing, and starting the opening cycle, or at the involves simultaneous movement of the head and end of the pressing the operator may press ag`base towards each'other, the distance traveled by push button which closes the air valve and opens eacl and the-time consumed in closing is cut in 15 L the exhaust. Y As soon as the diaphragm isdehalf. This is aurther important contribution l 'ilated the motor is energized and the press is to closing speed -A opened 'bythel mechanical movements actuated Movement of balanced moving members-reby the motor. The plates Vreturn to` their origduces wear and tear and increases the life of the inal position at which the pre-determined day- `press. .v y l 2o' -lightis again provided. l y J Theaccordion movement, by providing simuleA Eromthe construction and operation of the taneous contraction of the press fopeningsl terimproved press it will be particularly noticed minating in` simultaneous pressure contact, prothat some of the maior advantages secured byf vides an advantageous means of adjusting the 25 the'invention are as follows: n daylight to the' thickness; of the panels to be 25 Hot pgesses are relatively costly machines and pressed. Thisveliminatesunnecessary travel and l must attain 'maximum output to justify them'- the waste of opening and closing time in such selvespeed in opening and closing. is a'majoi; idle movement, This, in turn, increases producfeature'in production. Any reduction in the rel- Yr`tion and provides a further gain in aquicker 'atively idle time consumed in closing and-openapplication of 'bondingxpressura which assists in 30 ing, as in the present invention, increases the vavoidinginjury to the` heat sensitive adhesive. number of pressings per hour or .per day. Where all the spaces begin to open up at the Heat beginsto act upon an adhesive as soon same time and at the .same rate, the unloading as it penetrates to the glue line.v If the heatof the press can begin the moment the panels are 3 5, reaction prficeedsfar before the application orA released from pressure, 'and in turn, reloading 35 full bonding pressure, the bond is .either absent can start before the spaces are fully opened and or-inferior. is especially true with`r recently can continue after the spaces begin to close. This developed quick setting adhesives. .The quick is a' further economy in the timecycle required closing 'features of this` press design avoids this for` each pressing. 40 defect. `vWhile movement ofthe heavy members of the 40 To obtain ea product which is both uniform press has been speeded up by balancing the and o'rf ythe highest 'quality it is essential that weight, and whilev the time of opening and clostheY panels in all Ispaces ofa hot press receive ing has been .halved by moving headand base identical and ideal heat and pressure treatment. simultaneously, the rate of closing the individual The present invention provides this uniformity openings has. 'been greatly slowed down. Thisd because all press openings begin to close at the seeming paradox is explained as follows: If in a. f same instant and close uniformly and simulve opening press panels one half inch thick areA taneously at the same rate. This is the result being treated the 'space should be about one and'. of `the diierential closing movement and is an pne half inches in height if one inch of space is important advance over the conditions which V'provided above: each panel ior-ease in entering sa prevail in a press havingthe priorfart. progres- 'into the press. 4It would then require a movement sive closing movement In the latter, a panel/ of five inches to close all five spaces; The head lying -`in vthe opening 'that ,closes rst, receives would travel two and one half `inches, and the thevweight of the plate above it and is in conbase two and oneA half inches. Since all spacesl tact with the hot plates throughout bcthof its close together andsince each space to be closed is 55 surfaces, but the mechanical pressure is' only one inch, the space closing rate compared with f very low` and consequently theheat quickly peni the head and base -rate of movementisas one is 'eilates t0 the glue line from the plates causing to two andv one half or as two'is to `five.' The tha adhesive tQ'begn t0 reat in the absne 0f plates vin closing, approach eachother; at only blinding Prissura fstin Withut bonding Pres' two fthsthe'sped of the head and base move- 00 sure the Wegtof s cssi've plates is' Sided as ment. .In other words the platesNconie together uccessive. @m5 above thmtom one alfein the same elapsed time as the head andl base, closed up' Thus with pmgrssive closing great. liitthe latter travels two and one halftimes as y in qxaliw exists as regards the heat treatment f r nd tw d o ihan times s fast .ums a of theadhsive in the panels obtained from the'- a Q anne e5` several openigs. A'further objection vlies in vel? gentle and 510W clm of the ind-mdlal ai". have been obtained notwithstanding the V sthe shocks orybumps receiied by the panels in spa-'ces 1 K t i. the lowenspaces as eaclr space vis closed andthe greainicease'm @tal .closin Spee@ f the prss' piate'n'ext above it picked up. Awith any nigh The use Ofeadaphrasm' a Separate means -m closingspeed-vthese bumpsact to niompresis` the for applylngkworking pressure vhas advantages 70 d wood ailectinfthe final thickness of the 'iin-,f -fullyset forthin co-pending'applications. butaishe'ci'pan'elsr and thefaihesiveislalso disturbed i'l'lrther advantage ,has lbeen secured by sub' midi-3D1 the-s'm'ieet -Th Qn-Stl'llcf stitutingainfor liquid as the pressure instrument tion -here-4 escribed not only eliminates these .in thediphragm. lThe speed at'which air builds i 'vs -{bumpsor beforethe applica- ,upoperatih'g pressure as comparedrto liquids I5 u I r l s contributes to speed of operation and consequent increased output. I

A further advantage is the shock absorbing cushioning eifect of the air as. compared to liquid ,in absorbing the shockl of closing on the panels.

'I'his both relieves the mechanism of Wear and tear and makes greater closing speed permissible;

Other modes of applying the'prnciple of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or

plywood, upperv and lower press-heads, a series for each` plate, and arms swingably mounted on ythe equivalent of such, be employed. We therefore particularly point out and distinctly claim as our invention:

1. In a platen press'` adapted for laminating of plates therebetween, "and means ,for movably supporting 'said plates, including hanger 'rods 2. In a platen press adapted for laminating 5 plywood, upper and lower press-heads, a series of plates therebetween, and means for movably supporting said plates, including hanger rods for eachl plate and arms swingably mounted on the 10 upper press-head `forA arcuate movement in a vertical plane, the upper ends of said plate hanger rods being carried by said arms, take-up springs interposed between the upper ends of said plate hanger rods "and said arms, and means for 15- arcuately moving said arms in relation with the press-head movement. y

j RICHARD W. STANLEY.

ERICSSON H. MERRITT.

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