US3047051A - Laminating press - Google Patents

Description

July 31, 1962 A. MATVEEFF LAMINATING PRESS 4 Sheets-Sheet 1 Filed July 16, 1958 INVENTOR. BYALEXANDER MATVEEFF ATTORNEYS July 31, 1962 A. MATVEEFF 3,047,051

LAMINATING PRESS I Filed July 16, 1958 4 Sheets-Sheet 2 ilililililiiilili Slilililiii'i m mvm ATTORNEYS.

July 31, 1962 A. MATVEEFF LAMINATING PRESS 4 Sheets-Sheet 3 Filed July 16, 1958 F/G. I3

IIII'IIIIII'I'II'III'I F H ME TV NT E A M mR M g N A a 0N g 4, v w

WWW

ATTORNEYS.

July 31, 1962 A. MATVEEFF LAMINATING PRESS 4 Sheets-Sheet 4 Filed July 16, 1958 INVENTOR.

ALEXANDER MATVEEFF [Ln/F ATTORNEYS.

United States Patent ()fifice 3,047,051 Patented July 31, 1962 3,947,051 LAMINATING PRESS Alexander Matveeli, Tomkins Cove, N.Y.,- assignor to Glassoloid Corporation of America, Clifton, N.J., a corporation of New York Filed July 16, 1958, Ser. No. 748,858 3 Claims; ((11. 156-539) The present invention relates to the construction of a press designed to laminate a plurality of sheets of plastic material, with or without the interposition therebetween of non-plastic material, and to the organization of a system for controlling the operation thereof. I

There is a great demand for machines which will cover documents or photographs with sheets of transparent plastic material for purposes of preservation, attractiveness and ready handling. For example, in many establishments each employee is issued an identification card which may include a photograph as well as data indicating his identity, his job, and perhaps the places in the plant where he is permitted to go. Each time that a new employee is hired, or each time that an old employee changes his status, a new card is required, and in large enterprises a truly surprising number of identification cards must be issued each month. These cards are subject to considerable wear and tear, and consequently must, as a practical matter, be protected. This is commonly done by sandwiching the card between a pair of transparent plastic sheets which are sealed to one another along their edges, thus producing a unitary laminated product. The same procedure is employed to protect photographs, driving licenses, credit cards, and many other types of documents.

The laminated object is formed by subjecting the document and plastic sheet sandwic (the term sandwic will be employed hereinafter to refer to an assembly of outer plastic sheets with an object therebetween) to heat and pressure sufficient to press the plastic sheets closely against the document therebetween and to cause the projecting edges of the plastic to be pressed against and sealed to one another. Pressures on the order of 200 lbs. per square inch and temperatures on the order of 250 F. are usually required. These pressures and temperatures will vary depending upon the nature and composition of the sandwich. If excessively high pressures and temperatures are employed the sandwiched document may become damaged. If the pressures and temperatures are insufficient, or if they are applied for insufiicient periods of time, the lamination may be faulty.

A special problem is involved when a large number of sandwiches must be made in a short period of time, when the time involved in effecting a lamination is otherwise critical, or when only relatively unskilled personnel are available to perform the operation. Because the sandwich must be subjected to high temperatures for an extended period of time, it is quite hot when the lamination process has been completed, as are the parts of the laminating equipment which press the plastic sheets together. If the sandwich is permitted to cool in the laminating machine without artificial assistance a long period of siderable skill, time and trouble are involved in prepar-- ing the sandwich for lamination. It is usually not enough merely to place the sandwich in a press. Means must be provided for cushioning the effect of the'press and ensure that the pressure is applied evenly over the entire surface of the sandwich.

The equipment of the present invention solves all of the above problems in a signally effective manner. It is small enough so that it can be placed on a desk top or counter. place to place. By reason of its internal construction the making of the sandwich is greatly simplified and the insertion of the sandwich into the apparatus is substantially foolproof. The-lamination process is carried out entirely automatically; the operator need merely start the equipment running and may then walk away. The sandwich is cooled in the press, and that cooling, through appropriate and novel control of the various steps involved in the process, is effected in a significantly short period of time, by opening the press and using artificial means to cool the press and the sandwich at the same time, but separately. The overall operation of the device is substantially foolproof.

According to one aspect of the present invention the sandwich is cooled in the press by causing a flow thereover of air at room temperature, this cooling effect continuing automatically'until temperatures of a predetermined minimum value have been reached. The press is caused to open while this flow of cooling air is operative, and in a preferred embodiment the sandwich is supported in the press so that the air can cool both surfaces of the sandwich simultaneously. The heated press platens are provided with passages through which the flow of cooling air (not the same air that cools the sandwich) can pass in order to facilitate platen cooling at the same time that sandwich cooling is taking place.

In accordance with another aspect of the present invention the press platens are so constructed that the surfaces thereof which engage the sheets to be laminated are formed of a material, such as that plastic sold under the trade name Teflon and having the chemical composition tetrailuoroethylene, which, despite the high temperatures to which it is subjected will provide proper cushioning for the sheets to be laminated, will not adhere to the sandwich, and will impart the desired smooth surface characteristic to the sandwich, those platen surfaces preferably being directly heated so as to' enhance the efiiciency of the apparatus.

In accordance with another aspect of the present invention the various operative parts of the equipment, including a press, press actuating means effective to close and open the press, and means for cooling both the press and the sandwich, are assembled together in order to define a small, light and compact piece of equipment.

In accordance with yet another aspect of the present invention a simplified automatic control system is provided for all of the operative parts of the press, the various laminating steps being carried out automatically from start to finish, with proper application of the desired temperatures, pressures and cooling for the appropriate periods of time. Means are provided for adjusting the pressures, temperatures and time schedules for different types of lamination, but when, as is usually the case, a particular type of lamination is carried out many times in succession, initial setting of the equipment for that type of lamination leaves the operator the tasks only of preparing the sandwich, inserting it into the apparatus, and initiating the operating cycle, as by pushing a button.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the construction and mode of operation of a laminating press with associated actuating and control- It is light enough so that it can be moved fromq is equipment, as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

FIG. 1 is a three-quarter perspective view of one embodiment of the present invention, the tray on which the sandwich is to be placed being shown removed for the placement of a sandwtich thereon;

FIG. 2 is a side elevational view of the device, but with a side wall of the cabinet removed;

FIG. 3 is a side cross sectional view of the laminating press of FIG. 2, taken from the right hand side thereof as viewed in FIG. 2, differing from FIG. 2, however, in that a different and preferred type of platen is employed, with a correspondingly different arrangement of elements between the platens, the press being shown in partially closed position;

FIG. 4 is a cross sectional view taken along theline 44 of FIG. 3;

FIG. 5 is a cross sectional view of an alternative platen construction specifically shown as a bottom platen;

FIG. 6 is a three-quarter perspective exploded view of that type of sandwich shown in FIG. 3;

FIG. 7 is a cross sectional view thereof after lamination has been completed;

FIG. 8 is a three-quarter perspective exploded view of a second form of sandwich;

FIG. 9' is a cross sectional view of the sandwich of FIG. 8 after lamination has been completed;

FIG. 10 is a three-quarter perspective view of a modified form of tray on which the sandwich may be placed preliminary to being inserted into the apparatus;

FIG. 11 is a side elevational view of an alternative press construction having a non-removable tray, the press being shown in fully open position;

FIG. 12 is a cross sectional view taken along theline 12--12 of FIG. 11;

FIG. 13 is a cross sectional view similar to FIG. 4 but showing the tray of FIG. 10 and the sandwich of FIG. 6 used in conjunction with the non-removable tray of FIGS. 11 and 12; and

FIG. 14 is a circuit diagram of a preferred control system.

INTRODUCTION The operative parts of the lamination apparatus of the present invention comprise a heated laminating press generally designated A, actuating means therefor generally designated B and comprising a reversible hydraulic pump together with appropriate control equipment, a motor operated blower generally designated C for producing a flow of cooling air, and a tray generally designated D on which the sheets to be laminated are adapted to be received.

There are many types of laminated sandwiches which the apparatus of the present invention is adapted to produce, typical sandwiches being disclosed in FIGS. 6-9. These sandwiches comprise upper andlower sheets 2 and 4 of any appropriate thermoplastic material, at least one of which is usually transparent. In the sandwich of FIGS. 6 and 7 a paper sheet 6 is positioned between and is of a smaller size than theplastic sheets 2 and 4, so that theplastic sheets 2 and 4 extend beyond the paper sheet 6 completely around the periphery of the latter. Upon the application of heat and pressure theplastic sheets 2 and 4 are softened, the paper sheet 6 may imbed itself in them '(or one of them), and the outwardly extending peripheries of theplastic sheets 2 and 4 are welded to one another so as to completely seal and protect the paper sheet 6. In the embodiment of FIGS. 8 and 9 anaddiitonal sheet 8, which may be a photograph or the like, is positioned on top of the sheet 6' and beneath the plastic sheet 2, the end result again being an imbedment of thedocuments 6 and 8 in theplastic sheets 2 and 4 and a sealing of the plastic sheets around the documents. Although the term document is here used s with reference to theelements 6 and 8, it will be appreciated that the word is used in its broadest sense as indicating something which conveys intelligence, even though it may be in a most elementary form. Thus either thesheets 6 or 8, or both, could constitute color samples,

specimens of plant, animal or mineral matter, or almost General Description of the Apparatus All of the operative parts of the apparatus are enclosed within a casing generally designated 10 having afront wall 12 with an opening 14 formed therein through which the sheets to be laminated may be inserted. The press A is located in the casing 10 immediately inside thefront wall 12. It comprises, in the form disclosed in FIG. 2, abase 16 secured to the bottom wall 18 of the cabinet from which struts 2i extend upwardly. A fixed upper platen generally designated 22 is secured to thestruts 20 in any appropriate manner as by welding 24. A lower and movable platen generally designated 26 is positioned inside thestruts 20 beneath theupper platen 22 and is adapted to be moved toward and away from the fixedupper platen 22 by means of an hydraulic ram generally designated 28 which may be mounted in thebase 16.

Theupper platen 22 comprises atop metal plate 30 welded to thestruts 20, to the undersurface of which anasbestos pad 32 is secured. Ametal plate 34 is secured to the undersurface of thepad 32 and is provided with a series of spacedfins 36 extending generally inwardly from thefront cabinet wall 12 so as to provide a plurality ofpassages 38 through which air can flow, thefins 36 andpassages 38 in the embodiment of FIG. 2 being located at the top of theplate 34. Secured to the lower surface of theplate 34 may be a polished metal plate 40, with an electrical heating layer 4-2 interposed between theplates 34 and 40. The lower surface of the plate 40 is substantially in line with the upper edge of the opening 14 in thefront cabinet wall 12, and alouvre 44 may be provided in thefront cabinet wall 12 so as to permit air access to the outer ends of thepassages 38.

Thelower platen 26 is similar to thetop platen 22 and comprises, reading from bottom to top, abottom metal plate 46, anasbestos pad 48, aplate 50 provided withfins 52 andair passages 54, aheating element 56 and a polishedtop plate 58. Thebottom plate 46 of thelower platen 26 is connected to thepiston 60 of thehydraulic ram 28 in any appropriate manner, as byscrew 62 andspherical thrust washers 64. When theram piston 60 is withdrawn and thelower platen 26 is lowered the upper surface of itstop plate 58 is substantially in line with or somewhat below the lower edge of the opening 14 in thefront cabinet wall 12, and alouvre 66 may be provided in the front cabinet wall 12' to provide for air access to theair passages 54.

:Mounted on the opposite side of the press A from thecabinet front wall 12 is a blower generally designated 68 which is driven bymotor 70 and which acts to suck air in axially and eject it tangentially out through theopening 72 in the cabinettop wall 74. Theblower 68 is so positioned that its axial air intake is substantially in line with the opening 14 in thefront cabinet wall 12 and hence with the space between theplatens 22 and 26 when the latter are spaced apart.

Mounted in thecabinet 12 adjacent its rear end is a reversible hydraulic pump generally designated 76 which is connected bypipes 78 to theram 28. Thepump 76 is driven by a reversible electric motor comprising an armature 8t) and a field winding 82 (see FIG. 14). ,A pressure sensitive switch generally designated 84 is associated therewith, and the pressure setting thereof may be adjustable from the rear of the apparatus at 86. Thetank 88 for reception of the hydraulic fluid for thepump 76 and theram 28 may be filled throughpipe 90 at the rear of the apparatus. Alimit switch 92 is associated with themovable platen 26 and is adapted to be normally closed and to open only when themovable platen 26 has been fully lowered.

When a sandwich of the type shown in FIGS. 6 and 7 is to be laminated with thepress platens 22 and 26 of the type shown in FIG. 2, thesandwich sheets 2, 4 and 6 are placed upon the tray D while the latter is withdrawn from the apparatus. In order to provide for even application of pressure to the sheets 2--6 when platens of the type shown in FIG. 2 are used it is usually required that acushioning sheet 92 of suitable plastic material be positioned beneath the lowerplastic sheet 4 of the sandwich, that a metal plate 94 be positioned atop the upper plastic sheet 2, and that a cushioning sheet @6 be interposed between the metal sheet 94 and the bottom plate 40 of theupper platen 22.

Preferred Platen Clonstruclion Theplatens 22 and 26' of FIGS. 3 and 4 differ from theplatens 22 and 26 of FIG. 2 in a manner which is believed to represent an important improvement in devices of this nature. In FIGS. 3 and 4 the upper platen 22' compnises a top 131313630, an asbestos sheet 32' and aplate 34 provided with fins 36' and passages 38', similarly to theplaten 22 of FIG. 2, but with the exception that the plate 34' is not as thick as theplate 34 of FIG. 2, this latter differentiation being optional. Secured to, the underside of theplate 34 is an assembly comprising a core 93 formed of heat resistant material such as glass cloth impregnated with Teflon, around which theheating wire 100 is coiled. Thisassembly 98, 100 is itself sandwiched between a pair ofplastic sheets 102 and 104, theupper sheet 102 being adhesively secured to the plate 34' by means of a suitable thermosetting adhesive, thesheets 102 and 104 being secured to one another around their periphery and outside theheating element 98, 100 also by means of a thermosetting adhesive. 'The combined thicknesses of thesheets 102 and 104 may be on the order of 0.1 inch. In a preferred embodiment theupper sheet 102 has a thickness of .030 inch and thelower sheet 104 has a thickness of .060 inch. The material of which these sheets 1%2 and 104 are formed is such that it will present a smooth surface at the end of the platen where the sandwich to be laminated is engaged, it will at laminating temperatures of approximately 300-350" F. become cushion-soft without losing its shape or cohesion, and it will at those temperatures exhibit no adhesion to the materials being laminated. The material having the chemical composition tetrafluoroethylene and sold commercially under the trade name Teflon has proved to be exceedingly effective for this purpose. The adhesive which secures thesheets 102 and 164 to one another and to the plate 34' is thermosetting so as to be unaffected by the temperatures to which it will be subjected during thebperation of the apparatus.

The lower platen 26' is constructed similarly to the upper platen 22', and comprises thebase plate 46, the asbestos sheet 48', the metal plate 50', theribs 52 andair passages 54, theheating assembly 98, 100 and the coveringsheets 102 and 104 therefor.

The platen construction disclosed in FIGS. 3 and 4 has many advantages. Theheating elements 93, 100 are located very close to the surfaces which engage the material to be laminated, and the plastic interposed between said elements and said surfaces is of low specific heat, thus making for a rapid cycle of operation and efficient use of heating current. The heated portion of the platen is comparatively thin and consequently may rapidly be cooled. The lower surface of theTeflon sheet 104 imparts a desired smoothness to the upper surface of the upper plastic sheet 2 of the sandwich. TheTeflon sheets 102 and 104 become sufficiently soft at laminating temperatures to provide for adequate cushioning. Consequen-tly when the platens of FIGS. 3 and 4 are employed it is no longer necessary to utilize the cushioning andmetal layers 92, 94 and 96 shown in connection with the embodiment of FIG. 2.

Alternative Constructions FIG. 5 discloses an alternative construction for a portion of the platen. The plate 50a there disclosed has itsribs 52a and its air passages 54a positioned between the upper sandwich-engaging surface 40a and the heater element 42 which is imbedded in the lower portion of the plate 50a. of the sandwich-engaging portion of the platen is facilitated, but the heating thereof is somewhat less efficient.

FIG. 10 illustrates an alternative embodiment for the tray D. The tray D of FIG. 1 may beformed of metal. The tray D of FIG. 10 may be formed of softer material than metal so as to itself provide for cushioning;

In a preferred form it may be made of Teflon or a fabric impregnated with Teflon. It comprises a bottom portion 1% and atop portion 108 foldably associated therewith and of approximately the same size. The sheets to be laminated, such as thesheets 26 of FIG. 6, are placed on thebottom portion 106, thetop portion 108 is folded thereover, and the tray D is then inserted into the apparatus, the bottom and top portions 1% and 108 providing for appropriate cushioning and also imparting to the exposed surfaces of theplastic sheets 2 and 4 the desired surface characteristic.

Preferred T ray Mounting In FIGS. 11 and 12 a preferred arrangement isdis walls 110 having an appropriately positioned vertically elongatedaperture 112 therein through Whichears 114 on the tray D extend. Thus, as may be seen from FIG. 11, when thelower platen 26 is completely withdrawn theears 114 will engage with the bottom of theopening 112, the bottom of theopening 112 acting as a positive stop structure to support the tray D, with a space 116 between itself 'and thelower platen 26. This space 116 is of particular significance in connection with the cooling step hereinafter described, since it permits cooling air to flow over both top and bottom of the sandwich and permits the sandwich to cool independently of the platen-s 22 and 26. Hence the sandwich will, at the end of the cooling step, usually be at a lower temperature than the platens. When thelower platen 26 rises it will engage the tray D and move it upwardly until the sandwich positioned thereon is pressed against theupper platen 22, theslots 112 being sufficiently vertically elongated to permit this to occur. FIG. 13 discloses the operative position of the various parts when the non-removable tray D and the foldable Teflon tray D are both employed in conjunction with the eflicient and effective platen constructions of FIGS. 3 and 4.

Laminating Cycle Control System mensions are 8 x 16" x 11" and its total weight is approximately fifty pounds. It is expressly designed to be used almost any place and moved from one place to another.

With this arrangement cooling" Its overall di- Accordingly controls have been built into the,

4 apparatus which will enable it to be used to make many different types of laminations but which will at the same time permit it to be used by unskilled personnel. The control system is shown schematically in FIG. 14.

In order to produce a proper lamination the sheets to be laminated must be pressed together with the proper pressure and must be maintained at the proper temperature for a proper period of time in order for theintermediate sheets 6 and 8 to imbed themselves in one or both of thecovering sheets 2 and 4 and in order for the projecting edges of thecovering sheets 2 and 4 to properly bond to one another. If the temperature, pressure or time of curing is insufficient a faulty lamination will result, and if any of these variables are too great theintermediate sheets 6 or 8 may be damaged or thecovering sheets 2 and 4 themselves may be burned or unduly thinned and elongated. Moreover, the sandwich is hot when the lamination procedure has terminated, and if it is handled improperly before it is cooled it may be marred for damaged. Means must be provided to minimize the possibility of injury to the sandwich and to the operating personnel.

In accordance with the present invention all of the variables involved in the laminating cycle may be adjusted to fit a particular application, but the actual operation of the machine when the proper settings have been made is entirely automatic and all of the variables are accurately controlled. The system by mens of which this is accomplished is illustrated schematically in FIG. 14.

The two sides of a source of appropriate AC. or DC. power are designated 118 and 121i. Connected inline 120 is a power switch 122 and afuse 124, both accessible on thefront casing wall 12. Apilot light 126 mounted on thefront casing wall 12 is connected to line 118 bylead 128 and is connected to line 120 belowfuse 124 by lead 130, so that thepilot light 126 will be illuminated Whenever the switch 122 is closed. The heating elements for theplatens 22 and 26 are designated 132 in FIG. 14. They are connected to line 118 by lead 134 and are connected toterminal 136 ofpower relay 138 by means oflead 146 and adjustablethermostatic heat control 142. By appropriate settings of the movable element 144 of thecontrol 142, as by manipulation ofknob 143 at the rear of the casing, which will apply a predetermined tension to thethermostatic switch assembly 146, the maximum temperature to which theplatens 132 will be raised is determined. The blower motor is connected to line 118 bylead 148 and is connected toterminal 150 ofpower relay 138 by lead 152 andthermostat 154 which may be located in one of theplatens 22 or 26. Thethermostat 154 is designed to be closed whenever the temperature which it senses exceeds a predetermined value, which value in the instant application is that temperature, approximately F., to which theplatens 22 and 26 are to be cooled at the end of a cycle before the sandwich is to be removed from the casing.

Thepower relay 138 is provided with a pair ofswitch arms 156 and 158 which normally assume the position shown in FIG. 14, engaging terminals and 1611 respectively, until such time as the actuating coil 162 is energized, after which they will engage theterminals 164 and 136 respectively. Thearms 156 and 158 are both connected by lead 166 to theline 120 via the lead 134).

Theheat control unit 142 controls the maximum temperature to which the platens are heated. Thetiming unit 168 controls the length of time that the platens are to be heated. Thetiming unit 168 comprises normally closed thermostatic switch assembly 170 adapted to be heated bycoil 172 the current through which is determined by variable resistor 174, the setting of the resistor- 174 by manipulation ofknob 175 on thefront casing wall 12 thus controlling the time which will elapse before the normally closed thermostatic switch assembly 170 opens. Thecoil 172 is connected at one end vialead 176 to lead 140 and terminal 136, and is connected at its other end, through the resistor 174 and lead 17 8, toline 118. One

end of thethermostatic switch assembly 176 is connected to lead 1'76, and its other end is connected bylead 180 to point 182, from which lead 184 goes to the powerrelay actuating coil 112, and from which lead 186 goes to normallyopen starting switch 188, controlled bybutton 189 on thefront casing wall 12. The opposite end of the power relay actuating coil 162 is connected byleads 190 and 192 to normally closed reject switch 194, controlled by button 195 on thefront casing wall 12, and from there vialead 196 toline 118.

The other end of the startingswitch 188 is connected bylead 198 toterminal 200 of reversingrelay 202. That relay comprises an actuating coil 204 and four switcharms 206, 208, 210 and 212, which, when the coil 204 is tie-energized, assume their position shown in FIG. 14 in which they engage respectively withterminals 214, 216, 218 and 2111). When thecoil 284 is energized thecontact arms 206, 208, 210 and 212 will move so as to make electrical connection with theterminals 220, 222, 224 and 226 respectively. Theswitch arm 212 is connected bylead 228 toline 128. The terminal 226 is connected bylead 236 to one end of athermostatic switch assembly 232 the other end of Which is connected by means ofleads 234 and 236 toterminal 164 ofpower relay 138.Leads 234 and 236 are connected atpoint 238 to lead 240 which goes to one end of the reversing relay actuating coil 204, the other end of that coil being connected bylead 242 toleads 190 and 192 atpoint 24 4. Terminal 161 of thepower relay 138 is connected bylead 246 to one end of theheating coil 248 for thethermostatic switch assembly 232, the other end of thecoil 24 8 being connected by lead 251variable resistor 252 and lead 286 toterminal 224 of the reversingrelay 202. Thethermostatic switch assembly 232,heating coil 248 andvariable resistor 252 constitute means for delaying the opening of the press for a predetermined period of time.

The switch arm 206 is connected bylead 254 to one end of thearmature 80 of the motor for thehydraulic pump 76, the other end of thearmature 80 being connected by lead 256 to switcharm 208. One end of the field winding 82 of the pump motor is connected bylead 258 and fuse 260 toline 128. The other end of the field winding 82 is connetced by lead 262 to point 264 from which extend leads 266 and 268.Lead 266 connects with terminal 220 of the reversingrelay 202. Lead 268 goes to limitswitch 92 which is associated with themovable platen 26 so as to be closed only when themovable platen 26 has been fully lowered. The other end of thelimit switch 92 is connected by lead 270 to terminal 216. One end' of the adjustable pressure limit switch 84, sensitive to the pressure exerted by the press when it is closed, is connected bylead 272 toline 118. Its other end is connected by lead 274 to terminal 222. is normally closed, and will only open when the pressure in the hydraulic system exceeds a predetermined value.

. The equipment is then ready for operation.

When the switch 122 is closed and when the press is open, in stand-by condition, thepilot light 126 will light, indicating that the power is on, and thepilot light 276 will light, indicating that the equipment is ready for a cycle of operation. A circuit is also completed by powerrelay switch ann 156 through theblower motor 70, but since the platens will be at a low temperature thethermostat 154 will be open and hence the blower will not operate.

The operator positions a sandwich to be laminated with-.

The switch 84" in the equipment and then presses thestarting button 189 to close theswitch 188. This closes the circuit through the actuating coil 162 of thepower relay 138, that circuit being traced fromline 118 to lead 196, normally closed switch 194, leads 192 and 190, the coil 162, leads 184 and 186, theswitch 188, lead 198,switch arm 212 and lead 228 tothe'other line 120. Theswitch arms 156 and 158 will move to engage ter-minals 164 and 136 respectively. This will establish a holding circuit for the coil 162 which may be traced fromline 118 throughlead 196, switch 194, leads 192 and 190, the coil 162, leads 184 and 180, the thermostatic switch assembly 170, leads 176, and 140, terminal 136, switch arm 158 and leads 166 and 130 toline 120. Consequently release of thestarting button 189 once it has been pushed will not inten'upt the cycle.

A circuit will also be established via switch arm 158 through theplaten heating elements 132 and theheat control device 142, and also through the heatingtime delay coil 172 and variable resistor 174 associated therewith. The platens will heat quickly to the temperature determined by theheat control unit 142, and thetime delay unit 168 will commence timing.

A circuit is also established fromline 118 throughleads 196, 192 and 142 to the actuating coil 204 of the reversingrelay 202, the other end of that coil being connected toline 120 vialines 240, 236, terminal 164,switch arm 156, and leads 166 and 130. Theswitch arms 206, 208, 210, 212 will then move to engageterminals 220, 222, 224 and 226 respectively. The pump motor will therefore be energized to cause the press to close, its circuit being traced fromline 118 throughlead 272, switch 84, lead 274, terminal 222,switch arm 208, lead 256,armature 80, lead 254, switch arm 206, terminal 220, lead 266, lead 262, field winding 82 and lead 258 toline 120. The press will continue to operate until the sandwich is compressed with suflicient force to open the switch 84. That force will continue to be exerted on thesandwich.

It will be noted that as soon as thepower relay 202 was energized the switcharm 210 moved away fromterminal 218, thus extinguishingpilot light 276 and indicating that the equipment was not ina condition to start a new cycle.

Actuation of thepower relay 138 also, by removing the switch am 156 from the terminal 150, positively opened the circuit to theblower motor 70.

The situation as thus described, with the press closed and exerting a predetermined pressure on the sandwich and with the platens heated to a predetermined temperature, will continue for such time as is measured by thetime delay unit 168. When that time expires the thermostatic switch assembly 170 thereof will open. This will break the holding circuit to the actuating coil 162 for thepower relay 138, and that relay will then return to its original condition. Theswitch arm 156 M11 close the circuit to theblower motor 70, and since the platens are at an elevated temperature thethermostat 154 will be closed and he blower will commence to operate, drawing a stream of cool air through thepassages 38 and 54 in the platens so as to cool it. The circuit to theplaten heating element 132 will, of course, be opened through mtzvement ot the switch arm 158- away from the terminal 13 'I he actuating coil 204 for the reversingrelay 202 will, however, not be tie-energized at this point. A holding circuit therefor may be traced fromline 118 throughleads 196, 192 and 242 to one end of the coil 204, and from the other end of the coil 204 throughleads 240 and 234 to thethermostat assembly 232 of the press opening time delay, the other end of that assembly being connected bylead 230, terminal 226,switch arm 212 and lead 228 to theline 120. De-energization of the power relay coil 162 will, however, establish a circuit through theheating coil 248 for thethermostat assembly 232, that circuit being traced fromline 118 throughlead 284, switch arm 210, terminal 224, lead 286,resistor 252 and lead 250 to one end of thecoil 248, the other end of thecoil 48 being connected bylead 246, terminal 160, switch arm 158 and leads 168 and toline 120. Accordingly, although the platens will no longer be heated and although the blower will be functioning, the press will remain closed for the period of time necessary for thethermostat switch assembly 232 to open. When it does open the actuating coil 204 for the reversingrelay 202 will be de-energized, the switch arms 206212 will re turn to their positions shown in FIG. 14, and the circuit through the pump motor will be established vialimit switch 92 but with a reversed direction of current through the armature '80. The pump will therefore operate to lower themovable platen 26, and will continue to do so until theplaten 26 is fully lowered, at which time thelimit switch 92 will open and stop the action of the pump motor. The blower will continue to operate, cooling the platens and the sandwich. When the constructional embodiment of FIGS. 11 and 12 is employed, it will be noted that air will be drawn over the upper and lower sides of the sandwich, thus facilitating the cooling thereof. When the platens have reached a predetermined lower temperature, such as 100 F, themermostat 154 will open and the blower will stop.

When the reversingrelay 202 is de-ener-gized and resumes its initial position thepilot 276 will light, thus indicating that, except for cooling of the sandwich, the equipment is ready for another cycle.

If at any time it should be desired to interrupt the cycle of operation, the switch button is pushed opening the switch 194 and simultaneously de-energizing the actuating coils 162 and 204 of thepower relay 138 and reversingrelay 202 respectively.

Thus it will be seen that all the operator need do isv to insert the sandwich into the apparatus andpush button 189. The rest is all automatic.

While but a limited number of embodiments have been here disclosed, it will be apparent that many variations may be made in the present invention without departing from the inventive concepts thereof as defined in the following claims.

I claim:

l. Lamination apparatus comprising a fixed casing having a front wall with an opening therethrough, and, within said casing, a press adjacent said front wall and including a pair of platens relatively movable toward and away from one another without escaping from said casing, said platens when separated having a space therebetween in line with said opening, a blower in said casing on the other side of said press from said front wall and in air flow communication with said opening, and means for actuating said press and moving said platens, the lower platen of said press being movable vertically and said press comprising a tray mounted between said platens for vertical movement between upper and lower positions, and stop structure engageable with said tray when said tray is below its upper position and effective to support it in its lower position against further downward movement, said lower platen when at its lower limit of movement being spaced below said tray and when in its upper limit of movement having engaged said tray and lifted it to its upper position.

2. The apparatus of claim 1, in which said platen comprises a pair of sheets of plastic material capable of softening without permanently losing shape at temperatures on the order of 300-35 0 F., between which sheets is received the heating element for said platen, said heating element comprising a coil of resistance wire wound about a glass cloth core.

3. The apparatus of claim 1, in which said platen comprises a pair of sheets of plastic material capable of softening without permanently losing shape at temperatures on the order of 300-350 F., between which sheets is received the heating element for said platen, said heat- References Cited in the file of this patent UNITED STATES PATENTS Whitehead Sept. 21, 1943 Anderson Nov. 8, 1949 Baldwin Mar. 14, 1950 12. Morrison May 30, 1950 Butler Sept. 5, 1950 Sayre Jan. 22, 1952 Langer Aug. 25, 1953 Gardner Oct. 4, 1955 'Fener June 25, 1957 Russell May 13, 1958 Elliott Mar. 18, 1960 Lane Apr. 26, 1960

Images