US2611725A

US2611725A - Heat seamer

Info

Publication number: US2611725A
Authority: US
Inventors: James M Humphrey; Grevich John Joseph
Original assignee: Harris Trust and Savings Bank Corp
Current assignee: Harris Trust and Savings Bank Corp
Priority date: 1950-10-16
Filing date: 1950-10-16
Publication date: 1952-09-23
Anticipated expiration: 1969-09-23

Description

P 1952 J. M. HUMPHREY ETAL 2,611,725

HEAT SEAMER 6 Sheets-Sheet 1 Filed Oct. 1e, 1950 FIG INVENTORS J- M. HUMPHREY BY J. J. GREVICH ATTORNEY Sept. 23, 1952 Filed Oct. 16, 1950 J. M. HUMPHREY EI'AL HEAT YSEAMER FIG- 2 6 Sheets$heet 2 ATTORNEY Sept. 23, 1952 J. M. HUMPHREY EIAL 2,611,725

I HEAT SEAMER Filed Oct. 16, 1950 G SheetS-Sheet s FIG- 3 INVENTORS J. M. HUMPHREY J- J. GREVICH ATTORNEY Sept. 23, 1952 J. M. HUMPHREY ETAL 2,611,725

HEAT SEAMER Filed Oct. 16, 1950 e Sheets-Sheet 4 FIG- 4 INVENTORS J. M. HUMPHREY BY J. J. GREVICH ATTO RN EY P 1952 J. M. HUMPHREY EI'AL 2,611,725

HEAT SEAMER Filed Oct. 16, 1950 6 Sheets-Sheet 6 i Q N g o L:

INVENTORS J- M HUMPHREY J. ,J. GREVICH ATTORNEY patented Sept. 2 3, 1952 2,611,725 g v f HEAT SEAMER.

James M. Humphrey, New Richmond, Wis., and

John Joseph Grevich, St. Paul, Minn., assignors, by mesne assignments, to Harris Trust and Savings Bank and W. H. Milsted, as trustees Application October 16, 1950, Serial No. 190,391

This invention relates to sealing and more particularly to a machine for providing a seam on thermoplastic articles or for forming a continuous sheet of such material from a plurality of sheets thereof and in which the seam may be provided with a binding strip if desired. This application is a continuation in part of copending application, Serial No. 715,576, filed Decemberll, 1946 which has resulted in U. S. Patent No. 2,554,360.

. ..In the forming of seams on thermoplastic materials three main factors are involved, these being time, temperature, and pressure. Many of the sealing machines heretofore utilized provided no means for varying these factors and consequently were only applicable to predetermined types and weights of material. In certain types of seams an added factor may be included by applying a solvent to the materials which assists informing the seams, and in making this type of scam it is desirable to control the quantity of solvent utilized. Many of the prior art machines were also cumbersome and were also relatively costly to manufacture and in many instances required highly skilled operation.

It is a'ccordinglyan object of this invention to provide a simple, inexpensive practical heat seamer of relatively light weight which can be used to efiiciently and satisfactorily join sheets or bodies with or without employing a joining or binding strip at the seam and in which the seam will be of the desired strength and of pleasing appearance.

A further object of the invention is to provide a sealing machine which may be operated continuously or intermittently much in the manner of a conventional sewing machine in order to provide a seam on thermoplastic articles or materials.

A further object of the invention is to provide a sealing machine in which the rate of feed of articles or materials between the sealing elements may be very closely controlled in order to control the time factor in the sealing operation.

It is a further object of the invention to provide a sealing machine in which the temperature of the sealing elements may be closely controlled, which temperature may also be varied during the operation of the machine and in which means is further provided to accurately control the pressure between the sealing elements.

A still further object of the invention is to provide a sealing machine in which a thermoplastic tape may be longitudinally folded and fed to the sealing'elements in order to provide a binding for 20 Claims. (01. 154-42.-3)' f the seam being "formed and in which means is provided to apply a'solvent to one side' of'theltape and to control the amount of solvent applied.

It is a further object of the invention toprovid' a sealing machine in which thermoplastic tape to form a" binding for the seam is supplied from a roll andin which means is providedto pull the tapefrom the roll and to renderthis tape-pulling means inoperative when'the tape is not being utilized. Y v v It is a further object 'of the invention tolp'rovide a sealing machine which'm'ay be economi cally constructed of readily availablelpar'ts and which may be operated by relatively unskilled labor.

Further objects and advantages ,of. the. invention will be apparent from the following descrip ti'on taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is an elevational viewshowing the'front or operators side of the sealing'machi'neof'this invention; f 1..

'Fig. 2, a top plan view of' the sealing machine shown in Fig. 1; I f. Fig.' 3, a fragmentary elevational view'from opposite side, as shown in Fig. 1,'withth'e house ings and covers. removed and showing "the arrangement of the'inechanismin the sealing machine of this invention; I I

Fig. 4, a fragmentary sectional view on the line 4+4 of Fig.'3and showing the variableispeed drive for feeding material to the sealing machine, Fig. '5, a longitudinal sectional view showing one of the sealing elements, the drivemeans therefor, and the means for control1ingthe'temperature of such heating elementsi Fig. 6, a fragmentary sectional view onithe line' 5-6 of Fig.5,and showing the meansfor, apply,- ingpressure betweenthe sealing elementsg...

Fig. 7, a sectional view on theline 1+1 of Fig. 2 and showing the means forapplying solvent to the binding tape and the tape-pulling means utilized with the machine of this invention?" Fig. 8, a fragmentary sectional view on the line 88 of Fig. 2 and showingthe means for supplying solvent to the solvent-applying means} Fig. 9, a fragmentary sectional view onthe line 9 9 of Fig. 7 and showing the means for render ing, the tape-puller inoperative during periods in which binding tape is not utilized; I; i If Fig. 10, a fragmentary sectionalviewshowing the means forremoving excess solventfrom the tape; '3 'i. U Fig. 11, a schematic circuit diagram on the :Qlfififi switch l5 controlling the heating elements in such rolls, there being three positions in the latter switch: Off, Hi-heat, and Regular heat;

Secured to the top of frame I0 is a work supporting table I6 which is provided with a plurality of parallel, spaced, longitudinally extending slots I'I each of which serves to receive a belt I8 extending throughout the length of the table IB ,'these belts serving to receive and convey work deposited thereon. Belts I8 are received over pulleys I9 at one end thereof, which pulleys are mounted on shaft which in turn is journaled in bearings 2| mounted on the frame I0. The opposite ends of belts I8 are received over pulleys 22 mounted on shaft 23 also journaled on bearings secured to the frame I9, shaft 23 being driven by a sprocket mounted thereon, which sprocket serves to receive a chain 24, which chain in turn'is received over a sprocket 25 mounted on'one of the sealing rolls, the structure of which will be'later described. I

To adequately inspect the work in progress a lamp 26 is provided which is mounted on a flexible conduit 21 of familiar goose neck type which permits adjustment of lamp 26 to any desired position. Conduit 21 is mounted on a portion 28 of the frame I0 and suitable electrical connections are provided to energize the lamp 26. Ali on and ofi'switch 29 may be provided on the lamp socket to conveniently control the same.

The sealing elements of the machine of this invention comprise a pair of sealing rolls 39 and 3 I 'rotatably mounted one above the other and between which the work is adapted to pass. These rolls may be provided with knurled surfaces or serrations in order to indent the work and provide a more efficient seal. Roll 30 is fixed to a shaft 32 which in turn is journaled in bearings received in uprights 34 which are secured to the frame I0. Roll 30 also serves to support the sprocket 25 which drives chain 24 and the conveyor belts I8. The shaft 32 is provided adjacent the end remote from the roll 30 with a spur gear 35 and a sprocket 36. Sprocket 36 serves to receive a drive chain 31 which is trained over a sprocket 38 mounted on a shaft 39 extending from a speed reducer 40. Speed reducer 49 forms a part of and is directly attached to a variable speed drive mechanism M which is supported by cross members 42 secured to frame I9 by screw-threaded fastening means or the like 43. Variable speed drive mechanism 4I also is attached to and supports a drive motor 44 of conventional type which is provided with a capacitator 45 mounted on the top thereof by a strap 46.

Variable speed drive mechanism is of conventional commercially available construction and includes a top plate 4'! which may be provided with indicia 48 to facilitate adjustment of a control arm 49 which is attached to a control shaft 50 extending within the mechanism 4| arm 49" being split as at 5| to permit convenient ad- 4 justment thereof on the shaft 50. The arm 49 is clamped to shaft 50 by screw-threaded fastening means or the like 52.

The outer end of arm 49 is provided with a slot 53 which serves to slidably receive a pin 54 secured to an arm 55 pivotally mounted at 56 on frame i9. Arm 55 is pivoted about its mounting 56 by a cable 51 which leads over a pulley 58 journaled in bearings 59 mounted on one of the cross members 42, the cable 5! extending downwardly as shown in Fig. l to an arm 60 which is fixed to a shaft 6| journaled in frame III adjacent the lower portion thereof. Shaft BI is also provided with a treadle 62 disposed in a position convenient to the operator in order to control the speed of operation of the sealing machine.

Actuation of treadle 62 will, as seen from the drawings, rotate or pivot the arm 55 about its mounting 56 in a counter-clockwise direction, as seen in Fig. 4, to move the arm 49 and thus actuate the control shaft 50 of the variable speed mechanism 4| to rotate the shaft 39 at a speed in accordance with the movement of the arm 49. With the arm 49 in the position shown in full lines in Fig. 4 the shaft 39 and elements driven thereby are at rest and with the arm 49 at its extreme position after movement in a clockwise direction as shown in dotted lines in Fig. 4, the shaft 39 will be driven at its maximum speed. It will thus be seen that the above-described mechanism provides a convenient mean for adjusting or controlling the time in which the thermoplastic material passing between the sealing elements is subjected to the pressure and heat imparted thereto, thus materially affecting the efliciency of the seal produced.

The upper sealing roll3I is mounted on a shaft 63 journaled in uprights 34 and is disposed directly above the lower roll 39. Shaft 63 is provided adjacent the end thereof opposite the roll 3I with a spur gear 64 which meshes with spur gear 35 mounted on shaft 32, thus providing a driving means for the upper roll 3|. The spur gears 35 and B4 are provided with the same number of teeth and consequently the shaft 93 is driven at the same speed as the shaft 32 and since the rolls 30 and 3i are of the same diameter the surface speed of the two is the same and consequently there will be no slippage between the thermoplastic material and the rolls during the sealing operation.

Since it is necessary that a variable downward pressure be applied to the upper roll 3| in order to effectively seal the material passing between this roll and the lower roll 39 there is provided means for accomplishing this result in the form of a coil compression spring 65 received about a rod 59 extending upwardly through the frame ID, the rod 55 having a threaded lower end 57 which receives a wing nut 98 serving to adjust the compressive effect of spring 95. The rod'GG may be provided with a collar 89 at its lower end to prevent inadvertent removal of the wing nut 68.

Rod 25 extends upwardly and is provided with a laterally extending portion 73 which, as shown in Figs. 3 and 6, is pivotally received in one end of a link Ii, the opposite end of which is pivotally mounted at 72 on a stud I3 secured in the upper end of one of the uprights 34 by a set screw I4. The link ll is guided by a slotted stud I5 which is also mounted in the upright 34 by a set screw 13.

The shaft 93 supporting the upper sealing roll 31 which passes through the upright 34 is journale'd. therein by an anti-friction bearing 11 which in turn is received in an elongated or oval aperture 13 provided in the upright 34. Directly above the bearing 11 there is provided a pin 19 slidably mounted in an aperture 89 in the upright 34, the lower end of pin 19 engaging the upper surface of bearing 11 and the upper end of pin 19 engaging the lower surface of link 1|. It will thus be seen that the compressive force exerted by compression spring 65 will tend to move the rod 66 downwardly and thus pivot the link 1| in a clockwise direction as viewed in Fig. 6 to move the pin 19 downwardly and exert a downward pressure on the bearing 11, shaft 63 and thus on the upper roll 3|. Any upward pressure exerted on the roll 3| will tend to move the shaft 63 upwardly and through link 1| the rod 66 will move upwardly against the action of compression spring 65. Adjustment of the wing nut 68 provides a convenient means for controlling the pressure exerted by the upper roll 3| upon the material passing between this roll and the lower roll 39 thus varying the bond secured in the seam being made at the time.

The sealing rolls 39 and 3| are each provided with an annular recess 8| in the rear surface thereof and in these recesses there is positioned a heating element 82 having resistance wire 83 disposed therein to provide the necessary heat to efiect the seal between the surfaces of the thermoplastic material. The recesses 8| are closed by cover plates 84 which cover plates are provided with spacing screws 85 threadedly received therein and locked in position by lock nuts 86, screws 85 serving to tightly position the heating elements 82 against the forward face of the recess 8| in the

rolls

39 and 3|. Also positioned in the plate 84 of the upper roll 3| is a thermostat 81 which may be of conventional construction and provided with a bi-metallic element which will move in either direction upon a change in temperature of the heating element 82. The bimetallic strip or element 98 serves to open and close contacts which control the flow of electrical current to the heating element 82, the position at which the contacts are opened and closed being controlled by a pin 89 extending through the thermostat and engaging the bi-metallic element 98. The position of the pin 89 and consequently the opening and closing points of the contacts associated with the bi-metallic element 88 is controlled by a pivoted member 99 extending through a nipple 9| to the interior of shaft 63 which is hollow. The inner end of member 99 serves to receive a rod 92 provided with a head 93 on the outer end thereof. Rod 92 extends through shaft 63 to the opposite end thereof and is connected to an adjusting member 94 by a set screw 95, member 94 being threadedly received in the end of shaft 63. Member 94 is also provided with a finger-engaging operating knob 96 and a dial 91 which may carry indicia indicating the degree of heat in the

rolls

39 and 3|, there being a pointer 98 secured to and rotating with the upper spur gear 64 whereby the dial 91 and setting of the thermostat 81 may be conveniently adjusted. By this means the temperature of the

rolls

39 and 3| may be adjusted to very close limits even during operation of the machine or, in other words, while the

rolls

39 and 3| are rotating.

The heating elements 82 disposed in

rolls

39 and 3| receive their energizing electrical current from slip rings 99 mounted on shaft 63 and slip rings I99.mount ed on shaft 32. Slip rings 99 substantially right angles thereto.

are engaged by brushes 'I9I slidably mounted'in a bracket of insulating-material I92 which in turn is secured to a member I93 mounted onuprights 34. Brushes I9I' are urged inwardly against the slip rings 99 by spring contact members I94. The slip rings I99 on the lower shaft 32 are engaged by brushes I slidably mounted in bracket I92, these brushes being urged inwardly against the slip rings I99 by spring contact members I96. The conductors from slip rings 99 and I99 which are connected to the heating elements 82 are disposed within the

hollow shafts

32 and 63 but for clarity of illustration these conductors are not shown in the drawings although they are illustrated in the circuit diagram of Fig. 11.

Where two sheets of thermoplastic material are to be sealed together it is often desirable to provide the seam with a binding strip and for this purpose there is provided in the machine of this invention a binding tape supply means which maybe mounted on a shelf or bracket I91 secured to the frame I 9. The tape supply means comprises an upstanding rod I98 which serves to receive and support a shaft I99 extending at Shaft I99 may be conveniently secured to upstanding rod I98 by a collar II9 which serves to threadedly receive a set screw, not shown, for clamping the same to the rod I98. Rotatably mounted on shaft I99 and held in proper position thereon by collars III is a mandrel 2 which may be provided with a plurality of longitudinally extending spring fingers II3, the outer diameter of mandrel II2 being slightly less than the inner diameter of a roll of tape I I4. The spring fingers -II3 serve to firmly engage the inner surface of the tape roll I I4 to hold the same in proper position on the mandrel and permit rotation and feeding of the tape therefrom.

Mounted adjacent the upstanding rod I98 on the bracket or shelf I91 is a tape-pulling mechanism comprising a friction or drive pulley II5 mounted on a shaft III; which is journaled for rotation in an upstanding bracket II'I secured to the shelf I91 by screw-threaded fastening means or the like I I8. Shaft I I6 extends through the cover or housing I2 and is provided on its inner end with a bevel gear II9 which meshes with bevel gear I29 fixed on upper roll shaft 63. Thus friction drive pulley |I5 will rotate with shaft 63 and the

rolls

39 and 3| in synchronized relation thereto.

Mounted adjacent the drive pulley II5 and in parallel relation thereto is a pressure pulley I2I which is rotatably mounted on anti-friction bearings I22 carried by a stub shaft I23. Stub shaft I 23 is eccentrically supported by a shaft I24 rotatably mounted in anti-friction bearings I25 in a boss I26 extending from the inner side of bracket II1. Shaft I24 is provided at its inner end with a collar I26 which may be secured in adjusted position by a set screw or the like I21. Also extending from collar I 26' is an actuating arm I28, the purpose and operation of which will be presently described. Pressure pulley I2I is provided with flanges I29 on each side thereof to guide and retain the tape passing thereover in a manner which will presently appear. A tape guide I39 comprising a loop of wire or other suitable material is mounted on the bracket II1 directly above the pressure pulley I2I and serves to guide tape being fed thereto. a V

As best shown in Figs. 1 and '7, tape I3| from the roll 4 passes through thaguidedoop I andniunder i the, pressure-pulley 'I2I. .from which pulley it passes'over the. friction or'drive pulley I I5 and under a laterally extending xportion I32 ofthe arm I28. Movement of the laterally extending portion I32 from the full line position to the dotted line position, as shown ,in Fig. 7, rotates the shaft I24 and due to the eccentric arrangement of stub shaft I23 connected thereto moves the pressure pulley I2I toward or away from the friction or drive pulley II5, as shown in ,full and dotted lines in Fig. 7. This mechanism serves to operate and stop the tape-pullingmechanism depending upon the de- -mandfor tape by the sealing machine.

The binding tape I31 is fed from the tapepulling mechanism. above-described to a tapemoistening apparatus by which a solvent is applied to' one surface of the tape. 'The tapemoistening apparatus comprises a receptacle I33 for receiving a suitable solvent, this receptacle being supported on the shelf I01. The solvent is'maintained at a level indicated by the line I34 in a manner to be presently described. Mounted within the container I33 are partitions I35 and I35, these partitions being provided with vertically extending slots I31. Rotatably mounted within the slots. I3'Iand for vertical sliding movement is a shaft I38 which serves to support a roller I39 the lower portionof which is immersed in thesolvent within the container I33, the slots I3? providing a convenient means for permitting removal of the roller I39 for cleaning purposes. Also rotatably mounted on partitions I35 and I56 insubstantially parallel .relation with the roller I35 is a guide roller I-III,

.the purpose and operation of which will presentlyappear.

The container I33 is supplied with solvent through an aperture MI in thepartition I36, this aperture communicating with a channel I 12 which in turn communicates with a well M3. Well I43 serves to receive the neck I I I of a bottle or other suitable solvent reservoir M5, this bottle being supported in inverted position, as best shown in .Figs. land 8,- by a looped wire I45 or other. suitable material extending around the bottle and being supported by a collar I4? secured by aset screw or the like I43 to a pedestal I55 mounted on the shelf I51. The bottle or reservoir iefiprovides a barometric feed for the solvent since the lower end of neck I45 is normally disposed below the level of the solvent indicated .by line I34. The bottle is supplied with a valve in the form of a washer I disposed inwardly offthe neck I of the bottle Hi5, this washer being of sufhcient diameter to close the neck when contacting the inner walls thereof and being supported by a rod I5I extending outwardly of the neck I MI, there being a compression spring .I52Hsecured to the lower end of rod- I5I and to theneck I44. Thus upon removal of the bottie .I45'upwardly from the'well I53 the spring I52 acting. downwardly on the rod I5I will .move the valve washer I50 into engagement withthe sidewalls of the neck I44 and'close the'same. .This valve structure is: similar to that used in the tanks of conventional home oil stoves or ranges --and operates 1 to provide a substantially constant level of solvent withinthe container I33.

Disposed-between the tape-moistening apparatus and thetape-puller is a tape-tensioning means comprising a box-like structure I53 having upstanding side walls I54 provided with vertical slots I55 and downwardly curved converging upperwalls I 56 which provide a surface for engagthe full line position.

ingthe: tape I3 I FSlidably and rotatablymounted within the slots I55 is agshaft I5I which serves to. support a roller I58 of sufficient weight 1130 urge the tape ISI against the curved surfaces I 56 to provide a sufiicient tension in the tape between the same and the tape-moistening mechanism. .A tape guide I59. is'securedy'to the 'boxlike structure I53 by screw-threaded fastening means or the like I60 and upstanding spaced flanges ISI are provided to properly guide the tape I3I to the tensioning roller I58.

Since it is desirable thatexcess solvent be re- .moved from-the surface of the tape I3 I. and since the. quantitywof solvent applied .thcretozmay need to be. varied in accordance with :the character of the material and the thickness of the plies rto'be joined thereis provided a wiper in the form of a rod I52 extending transverselyof the tape I3I and rotatablymountedin'the partitions I35.and I 35. Rod I62, as best shown in Fig. 10, is ofrirregular cross section and provides a relatively sharp edge I83 and a rounded or smooth surface I54. In Fig. 10 thesharp edge I53 isshown:in full lines in engagement with the tape vI3I and the rounded or smooth surface Ifit is shown in dotted lines in engagement with the tape. The rod I52 operates to wipe excess solvent from the tape I3Iand return this solvent to the container I33. Adjusting means for the rod 52 is provided intheform of a knurled finger-engaging knob J55 attached thereto, there being also provided a wing-type lock-nut 'I55,.threadedly received on the rodaifiito lock the same in adjusted position.

1 operation tape is fed from the roll II through the guideloop I38 and under the pressure pulley IZI, the flanges- I29 serving toretain the tape I3I thereon. From pulleyI2I the tape I3I passes over the friction drive pulley I I5 and under the lateral extension 532 of arm I28. From extension I 32 the tape passes over guide I59and between flanges I SI thence under the tension roller .158 which holds the sameinengagement with the downwardly curved surfaces I55. From here the tapepasses over the moistening roller I39 which applies solvent thereto and beneath-the roller I48 which, as shown in-F'ig. '7,

depresses the tape downwardly to insurethat the lower surface thereof remains in contact with the surface of the roller I39 at all times. From roller 14s the tape passes over rod I52 at which time any excess solvent on the lower surface thereof is removed and returned to the container I33. From this point the tape I3I is supplied to a folding mechanism I65, shown in general in Fig. l, the details of which form no part of this invention and therefore will not be specifically described... From the folding mechanism I66- the tape moves to the sealing rolls 38 and 3i and is applied to the sheets which are being fed therebetween by the conveyor belts I8. Since the friction drive pulley ii irotates in synohronism with the sealing rolls 3B and 3|, the tape I3I will be fed thereto at the same speed. However, if the tape I3I breaks or, for some reason it is not desired to utilize-the tape, release of tension thereon allowsthe lateral extension I32 of arm I28 to move from the-dotted line position in Fig. 7 to I This movement results 1n rotating the shaft I24 and eccentrically mounted'stub shaft I23 to move the pressure pulley I2I away from the friction drive pulley I I5, therefore interrup'tingthe feed of the tape in that therewill not besuflicient friction between the pulley us and the tape m to pull the same from :roll. H4. Upon reapplying tension te -the tape I3I the extension I32 of arm I28 will movefrom the full line position shown in Fig. '1 to the dotted line position, thus moving the pressure pulley I2I to press the tape I3I against the surface of friction drive pulley II5 thereby reestablishing the feed of the tape.

The electrical circuit of the sealing machine of this invention, as shown in Fig. 11, is supplied with electrical current through conductors I61 and I68 which are connected to a flexible supply cord provided with a conventional male-type connector at the outer end thereof. Connected to conductors I91 and I68 are conductors I89 which serve to supply current to the lamp 28 mounted on the end of goose neck 21. Also connected to conductors I81 and IE8 are conductors I19 which serve to supply electrical current tomotor 44, the operation of this motor being controlled by on and off switch I4.

Conductor I61 is connected to one contact I1I of a. normally open relay I12. Conductor I61 is also connected to one side of the coil I18 forming the solenoid of relay I12 and which, when energized, serves to actuate the movable contact I14 to closed position. The other contact I15 of relay I12 is connected through a wire I16 to one movable contact .I11 of a double pole, double throw switch I5.

The heating element 82 in upper roll 3| is provided with electrical current from the slip rings 99 mounted on shaft 83, there being one slip ring I18 connected to one side of the heating element 82 through a conductor I19, the opposite side of the heating element 82 being connected through a wire I80 with a second slip ring I8 I. The thermostat 81 disposed in the upper roll 9| has one contact I82 connected to the wire I89 and the opposite contact I83 connected by a wire I84 with the third slip ring I85. 2

The heating element 82 disposed in the lower heating roll 30 is provided with electrical current from slip rings I00, one one side of the element 82 being connected by a wire I89 with slip ring I31 and the opposite side of the element 82 being connected by a wire I88 with the second slip ring I89. Slip rings I18, I8I and I85 are contacted by brushes I90, I9I, and I92, respectively, while slip rings I81 and I89 are contacted by brushes I99 and I94, respectively. The second movable contact I95 on double pole double throwswitch I5 is connected through a wire I98 with the brush I9I engaging slip ring I8I and with the supply conductor I68. Contact I91 of switch I5 is connected through a wire I98 with contact I99 which in turn is connected by a Wire 280 with brush I99 engaging slip ring I89. Contact 291 of switch I5 is connected through a wire 292 with brush I 93 engaging slip ring I 80 and with brush I99 engaging slip ring I18. No connection is made to contact 283 of the switch I5 and this contact plays no part in the control of the sealing machine; Brush I92 in contact with slip ring I85 is connected by 'a wire 204 with the coil I13 of the relay I12. In order to prevent excessive arcing between the contacts I82 and I83 of the thermostat 81 a .1 mid. condenser'2'85 is connected across the brushes I9I and I92 in' contact with slip rings I BI and I85 which in turn are connected across the contacts I82 and I83 of the thermostat 81. This condenser materially increases the lifev of the thermostat contact points.

Assuming the sealing machine of this invention to beat rest and the heating elements 82 in the rolls 30 and SI to be cold the operation of the electrical supply and control circuit is as follows current is suppliedthrough the conductors I61. and I68 and the light 26 may be turned on or ofl'i at will, as well as may be the drive motor 44 ,by actuation of the switch I4. Current will further flow from conductor I61 throughcoil I13 or solenoid I12 to actuate the movable contact I14 thus closing the contacts HI and I15 since the complete circuitof the coil I13 will be to conductor 204 to brush I92 engaging slip ring I through the power line.

Assuming the double I15 of relay I 12 through conductor I16 to movable contact I11 of the switch I5 and through contact '20I and conductor 202 to brush I engaging slip ring I18 and through conductor I19 to heating; element 82, thence through conductor I80 to slip ring I 8| and through brush I9I and conductor- I96 to the opposite side of the power line I68 thusenergizing heating element 82 to heat thesame.

Likewise the current flowing through co'nductor 202 will flow through brush I93 engaging slip, ring I00 and through conductor. I86 heating ele-,

ment 82 in the lower roll 30 thence through .co'nductor I88 to slip ring I89 and brush I94'and through conductor 200, contact I99 of switch-I5 and contact I95 to conductor I96 and to the op-- posite side of the power line conductor I68. .In this condition the heating elements 82 will. con-- tinue to supply heat until the temperature of.

the

rolls

38 and 3| reach the point-at' -.which the thermostat 81 is set, at which time the contacts I82 and. I83 will separate thus de-energizing the coil I13 of, relay I12 and opening the contacts I1] and I 15 to interrupt'the flow of current tothe heating elements 82.

With the double pole throw switch I5 in the. regular or upper position, as shown in Fig. 11.,-

current will flow from contact us to the relay I 12 throughconductor I16to the movable con-,

tact I11 of switch I5 thence through Contact I91, conductor I98 and conductor 200 tov brushfll94i which engages slip ring I89, thence throughfcom' ductor I88 to the heating element 82in the lower roll .30 through conductor I86 to the slip ring I81 and through brush I93 and conductor 202 to'the brush I99-engaging slip ring I18 thence through conductor I19 to heating element 82 in the upper roll 3| which point the current flows through conductor I80 to slip ring I8I engaged by. brush I 9| from which the current-flows through wire I96 to conductor I68 forming the opposite side of the supply circuit. This position of the switch I5 places the heating elements 82 in series, thus resulting in a lower wattage consumption and consequently lower potential heat in the rolls30 and 9|. As before, the temperature will be controlled by opening and closing of thethermostat 81 which controls operation of the relay I12 and thus the supply of current to the heating elements. The electrical supply and control system above-described is relatively simple and. :ade-- quately controls the operation of the sealing machine of this invention. V

The operation of the sealing apparatus as a whole is believed apparent from the above description but briefly reviewing the sameit is as-.- sumed that the motor switch I4 isin the .onpo.-;:

pole, double throw switch: I5 to be in the high or downward position, as. shown in Fig. 11, currentwill flow from contactv sitin"and that the heating *elementcontrol switch i is in either the high or regular po-f sition depending upon the temperature required.-

Itis' further assumed that the thermostat 8 T isadjusted to the desired temperature. The binding strip or tape l 3! is threaded through the tapefeedingmeansand the tape-moistening means aswell. as through the'folding mechanism I55 and sheets of plastic or objects to be formed of a thermoplastic material arepositioned on the table-i6 with the folded tape disposed around theedges' and with the edges in a position to be introduced between the sealing rolls 3!] and 3|. At this time thetreadle 62-is actuated to move the controlcable 5'1 and actuate the arm 49 on the variable speed transmission Al to rotatethe rolls at the desired speed. The extent of movementofarm 39 is controlled by a flexibl'emembersuch-as a chain 266' attached to the-arm '55 andto the frame of the machine and the arm 55 and control arm 49 is returnedto its original position upon releaseofthe treadle 62 by a sprin or other suitable tension means '28! secured to the-arm 55 and tea bracket2fi8 attached to the frame- H] of the machine. The tension spring ZD-Fmay be adjusted by a rod 2% and screwthreaded means or the like emreceived thereon.

The work progresses through the machine and through; the sealing rolls 30 and 39 by the friction therebetween-as well as by the conveyor belts land upon completing of the seal the work is removed from the rolls and packaged or otherwise-disposed of. Control of the speed of rotation of the rolls 3!! and 3| by actuation of the treadle 62- controls the time in which the sealing heat and pressure is applied to the work, this being dependent upon the nature of the material as well asthe thickness thereof.

It 'will-be seenthat-by the above invention there has been provided a relatively simple and inexpensivesealing machine which adequately performs the functions for which it is intended.

It will be obvious to those skilled in the art that variouschanges maybe made in the invention without: departing fromthespirit and scope thereof: and therefore'ithe' invention is not. limitedby that which is shown in the drawings and. describedin thespecificationbut only as indicated in the appended claims.

What is claimed is:

1. Asealin machine for forming a seam between two sheets of thermoplastic material comprising in combination a frame, awork table on said frame for supporting superimposed sheets to bejoined with two adjacent edges in substantial alignment, conveyor means associated with said table 'for feeding said sheets longitudinally there of, spaced substantially parallel hollow shafts journaled-in said frameone abovethe other, a sealingroll'flxed to one end of each shaft adjacent an edge of saidtable, means for driving said rolls comprising a motor and a variable speed transmission, treadle means" mountedon said frame for controlling the output of said transmission whereby the speed of rotation of said rolls may be infinitely varied between zero and maximum, means on one of said rolls for driving said conveyor in synchronism-therewith, a heating element disposed in each roll, slip rings fixed on said shafts and brushes in contact therewith, conductors conneoted to 'said heating elements. and said slip rings and extending through said hollow shafts wherebyelectrical energy may be:supplied;:to said heating elements, a relay conted. mxanielectrical supplyi circuit for said heating elements, an adjustable thermostat: dis posed in one roll and connected through said with the tension in the tape fed therefrom, means for applying solvent to one surface of said tape,

means for removin excess solvent from said tape, I

means for longitudinally folding said tape upon itself and applying the same over the edges of said sheets to be joined whereby upon passing between said sealing rolls said sheets will be joined to said binding tape under the action of heat and pressure to form a continuous sheet.

2. A sealing machine for forming a seam between two sheets of thermoplastic material comprising in combination a frame, a work table on said frame for supportin superimposed. sheets to be joined with two adjacent edges in substantial alignment, spaced substantially parallel hollow shafts journaled in said frame one above the other, a sealing roll fixed to one end of each shaft adjacent an edge of said table, means for driving said rolls comprising a motor and a variable speed transmission, treadle means mounted on said frame for controlling the output of said transmission whereby the speed of rotation of said rolls may be infinitely varied between zero and maximum, a heating element disposed in each roll, slip rings fixed on said shafts and brushes in contact therewith, conductors connected to said heating elements and said slip rings and extending through said hollow shafts whereby electrical energy may be supplied to said heating elements, a relay connected in the electrical supply circuit for said heating elements, an adjustable thermostat disposed in one roll and connected through said slip rings to said relay whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasing said rolls towards each other whereby the pressure applied to work therebetween may be varied, means for supporting a supply of thermoplastic binding tape on said frame, tape-pulling means driven by said sealing roll drive means in synchronism therewith, means for rendering said tape-pulling means operative or inoperative in accordance with the tension in the tape fed therefrom, means for applying solvent to one surface of said tape, means for removing excess solvent from said tape, means for longitudinally folding said tape upon itself and applying the same over the edges of said sheets to be joined whereby upon passin between said sealing rolls said sheets will be joined to said bindin tape under the action of heat and pressure to form a continuous sheet.

3. A sealing machine for forming a seam between two sheets of thermoplastic material comprising in combination a frame, a work table on said frame for supporting superimposed sheets to be'joined with two adjacent edges in substantial alignment, spaced substantially parallel shafts journalednin said frame-one above the other,

a sealing-roll fixed toone end of each shaft adjacent an edge of'said table, means for driving said rolls comprising a motor anda variable speed transmission, treadle means mounted on said frame for controllin the output of said transmission whereby the speed of rotation of said rolls may beinfinitely varied between zero and maximum, a heating element disposed in each roll, slip rings fixed to said'shafts and brushes in contact therewith, conductors connected to said heating elements and said slip rings whereby electrical energy may be supplied to said heating elements, a relay connected in the electrical supply circuit for said heating elements, an adjustable thermostat disposed in one roll and connected through said slip rings to said relay whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one rollaway from the other, adjustable yieldable means for biasing said rolls towards each other whereby the pressure applied to work therebetween may be varied, means for supportin a supply of thermoplastic binding tape on said frame, tape-pulling means driven by said sealing roll drive means in synchronism therewith, mean for rendering said tape-pulling means operative or inoperative in accordance with the tension in the tape fed therefrom, means for applying solvent to one surface of said tape, means for removing excess solvent from said tape, means for longitudinally folding said tape upon itself and applying the same over the edges of said sheets to be joined whereby upon passing between said sealin rolls said sheets will be joined to said binding tape under the action of heat and pressure to form a continuous sheet. I

4. A sealing machine for forming a seam between two sheets of thermoplastic materialcomprising in combination a frame, a work table on said frame for supporting superimposed sheets to be joined withtwo adjacent edges in substantial alignment, spaced substantially parallel shafts journaled in said frame one above the other, a sealing roll fixed to one end of each shaft, means for driving saidrolls including a variable speed transmission, means mounted on said frame for controlling the output of said transmission whereby the speed of rotation of said rolls may be infinitely varied between zero and maximum, a heating element disposed in each roll, slip rings fixed to said shafts and brushes in contact therewith, conductors connected to said heating elements and said slip rings whereby electrical energy may be supplied to said heating elements, a relay connected in the electrical supply circuit for said heating elements, an adjustable thermostat disposed in one roll and connected through said slip rings to said relay whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movementof one roll away from the other, adjustable yieldable means. for biasing said rolls towards each other whereby the pressure applied to work therebetween may be varied, means for supporting a supply of thermoplastic binding tape on said frame, tape-pulling means driven by said sealing roll drive means in synchronism therewith, means for rendering said tape-pulling means operative or inoperative inaccordance with the tension in the tape fed therefrom, means for applying-solvent to one surface of said tape, means for removing excess solvent from said tape, means for longitudinally folding said tape tial alignment,

upon itself and applying thesameover the edges of said sheets to be joined whereby upon passing between said sealing rolls said sheets will be joined to said binding tape under the action of heat and pressure to forma continuous sheet.

5. A sealing machine for forming a seam be-' tween two sheets of thermoplastic material comprising in combination a frame, a work table on said frame for supporting superimposed sheets to be joined with two adjacent edges in substantial alignment, spaced substantially parallel shafts journaled in said frame one above the otherya sealing roll fixed to one end of each shaft, means for driving said rolls including a variable speed transmission, means mounted on said framefor controlling the output of said transmission whereby the'speed of rotation of said rolls may be infinitely varied between zero and maximum, a heating element disposed in each roll, means for supplying electrical energy to said heating elements, a relay connected in the electrical sup, ply circuit for said heating elements, an adjustable thermostat disposed in one roll and connected to said relay whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasingsaid rolls towards each other whereby the pressure applied to work therebetween may be varied, means for supporting a supply of thermoplastic binding tape on ,said frame, tape-pulling means driven by said sealing roll drive means in synchronismtherewith, means for rendering said tape-pulling means operative or inoperative in accordance with the tension in the tape fed therefrom, means for applying solvent to one surface of said tape, means for removing excess solvent from said tape, means for longitudinally folding said tape upon itself and applying-the same over the edges of said sheets to be joined whereby upon passing between said sealing rolls said sheets will be joined to said binding tape under the action of heat and pressure to form a continuoussheet.

6. A sealing machine for forming a seam between two sheets of thermoplastic material comprising in combination a frame, a work table on said frame for supporting superimposed sheets to be joined with two adjacent edges in substanspaced substantially parallel shafts journaled in said frame one above the other, a sealing r011 fixed toone end of each shaft, means for driving said rolls including a variable speed transmission, means mounted on said frame for controlling the output of said transmission whereby the speed of rotation of said rolls may be infinitely varied between zero and maximum, a heating element disposed in each roll, means for supplying electrical energy to said heating elements, an adjustable thermostat disposed in one roll and connected to said means for supplying electrical energy whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasing said rolls toward each other whereby the pressure applied to work therebetween may be varied, means for supporting asupply of thermoplastic binding tape on said frame, tape-pulling means driven by said sealing roll drive means in synchronism therewith, means for rendering said tape-pulllng means operative or inoperative in accordance with the tension in the tape fed therefrom, means for applying. solvent to one surfacezof :said:-tape,;means for .removing:-excess solvent.- fromsaid tape, means.v for longitudinally folding said tape ;uponitself and applying the samebverthe edges of said, sheets to be joined wherebyupon passingbetween said sealing rolls saidsheets will be joined to said binding tape under theyaction of heat and pressure to form a ;continuous sheet.

'7. -A-;sealing machineforforming a seambetween two sheets of thermoplastic material comprising inwcombination a frame, a work table on saidtframe for supporting superimposed sheets to be joined with etwoadjacent edges in substantial alignment, spaced substantially parallel shafts J'ournaled in;said frame one above the other, a sealing roll fixed to one endof eachshaft, means for:;driving said-rolls; including avariable speed transmission, means mounted on said frame for controlling the output of said transmission whereb'yrthe speedof rotation of said rolls-may be infinitely varied betweenzero and maximum, aheating element disposed in each roll, means for supplying electrical energy to said heating elements, an adjustable thermostat disposed in one roll and-connected to saidmeans for supplying electrical energy whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasing said rolls toward each other whereby the pressure applied to work therebe'tween may be varied, means for'supporting a supply of thermoplastic bindingtape on said frame, tape-pulling means driven by said sealing roll drive means in synchronism therewith, means for rendering said tape-pulling means operative or inoperative in accordance with the tension in the tape fed therefrom, means forrapplying solvent to one surface of said tape, means for longitudinally foldingsaid tape upon itself and applying the same over the edges of said sheets to be Joined whereby upon passing between said sealing rolls said sheets will be joined-to said binding tape under the action of heat and pressure to form a'continuous sheet.

8. A sealing machine for forming 'a seam between two sheets of thermoplastic material comprising in combination a frame, a work table on said frame for supporting superimposed sheets tobe-joined with'two adjacent edges in substantial "alignment, spaced substantially parallel shafts journaled in said frame one above the other, a sealing roll fixed to one end of each shaft, means for driving said rolls including a variable speed transmission, means mounted on said frame for controlling the output of said transmission'whereby the speed of rotationof said rolls may be varied between zero and maximum, a heating element disposed in each roll, means for supplying electrical energy to said heating elements, an adjustable thermostat disposed in one roll and connected to said means 7 for supplying electrical energy whereby the temperature of said heating elements may be controlled, means for adjusting said thermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasing'said rolls towards each other whereby the pressure applied to work therebetween may be varied, means for supporting a supply of thermoplastic binding tape on said frame, tape pulling means driven'bysaid sealing roll drive means-in;synchronismtherewith, means for applying solventtonne surface of said tape,'means .16 for: longitudinally foldin I ,saidtape upon itself and-applying the same .over the edgesof said sheets to be joined whereby upon passing between said'sealing rollsesaid sheets will be joined to said binding tape under the action of heat and pressure to form a continuous sheet. 9. A sealing machine forrforming a seam between two. sheets of thermoplastiomaterial comprisingin combination a frame, a work table on said frame for supporting superimposed sheets to be joined with ;two adjacent edges in substantial alignment, spaced substantially parallel shafts journaled in said frame one above the other, asealing rollfixed to one end of :each shaft, means forriving said grolls includinga variable speed transmission, means ,mountedon said framejfor controlling the output of-said transmission whereby the speed of rotation of saidrollsgmay be infinitely varied betvveensero and maximum, aeheating element disposedin each roll, means for-supplying electrical-energy to said heating elements, an adjustable thermostat disposed in one roll and connectedtosaid means for supplying electrical energy whereby the temperatureof said heating elements 1may be controlled, means for'adjusting saidthermostat, means for permitting movement of one roll away from the other, adjustable yieldable means for biasing said rolls toward each other whereby the pressure applied to work therebetween may be varied, means for supporting asupply of thermoplastic binding'tape on said frame, tape pulling means driven by said sealing roll drive means in synchronism therewith, means for longitudinally folding said tape upon itself and applyingthe same over the edges of said sheets to be joined whereby upon passing between said sealing rolls said sheets will be joined to said bindingtape under the action-of heat and pressure to form a continuoussheet;

10. A sealing machine as defined in claim 1 in which said tape pulling means comprises a friction roll driven by said sealing roll driving means, a pressure roll mounted adjacent said friction roll for movement toward and away therefrom, a stub shaft rotatably receiving said pressure roll, a shaft eocentrically secured to said stub shaft and rotatably mounted on said frame, an arm secured to said shaft and having a lateral extension disposed in the path of movement of tape trained over said friction roll whereby tape under tension passing'under said extension will rotate said shaft and move said pressure roll towardssaid friction roll to cause drivingengagement between said friction-roll and said tape to feed the same and uponrelease of tension in said tape said pressure roll will move away from said friction roll to interrupt said driving engagement.

11. A sealing machine as definedin claim 7 in which said tape pulling means comprises a friction roll driven by said sealingroll driving means, a pressure roll mounted adjacent said friction roll for movement toward and away therefrom, a stub shaftrotatably.receiving.said'pressure roll, a shaft ,eccentrically secured tosaid stub shaft and-rotatably, mounted on said frame, anarmsecured to said shaft and having a lateral extension disposedpin the path ofmovement of tape, trained ,over said friction roll wherebytape under tension passing underjsaid extension will rotate said shaft andmove said pressure roll towards said friction roll to cause driving engagement between said friction-roll and said tape to feed thesame' and uponreleaseof-tension in said tape, said pressure roll will move away from said friction roll o interrupt-said driving I engagement; V

12. A sealing machine as defined *inclaim"7 in which said tape pulling means comprises a friction roll -driven ;by;'-said -sealing roll driving means, a pressure roll mounted adjacent said friction roll for movementtoward and away therefrom, eccentric means" for mounting said pressure'roll on said frame, an-arm secur'edto said eccentric means and having a lateral extension disposed in the path of movement oftape trained overv said friction roll whereby tape under tension passing under said extension will move said pressure roll towardssaidfr tion roll toipause driving engagement between s id'friction-roll and driving engagement. l

13.'A sealing machine as" defined inclarmfl in which said tape pulling means comprises a friction roll driven by said sealing roll driving means, a pressure roll mounted adjacent said friction roll for movement toward and away therefrom, means disposed in the path of movement of tape trained over said friction roll and connected to said pressure roll for moving the same toward and away from said friction roll whereby tape under tension passing under said means will move towards said friction roll to cause driving engagement between said friction roll and said tape to feed the same and upon release of tension in said tape said pressure roll will move away from said friction roll to interrupt said driving engagement.

14. A sealing machine as defined in claim 7 in which said solvent applying means comprises an open top container, spaced substantially parallel partitions in said container, opposed vertical slots in said partitions, a solvent applying roller having a shaft removably received in said slots with the lower portion of said roller immersed in solvent in said container and with the upper portion of said roller above the level of the solvent, a second roller substantially parallel to said applying roller and rotatably mounted on said partitions with the lower portion of said second roller below the upper portion of said applying roller whereby tape passing over said applying roller and under said second roller will be held in firm engagement with said applying roller to receive solvent therefrom, a well adjacent said container, 2. channel communicating with said container and said well, a solvent reservoir having a filling and discharge opening formed by a neck, a valve disposed in said neck for closing the same, resilient means for biasing said valve to closed position and means to open said Valve, said reservoir being disposed in inverted position with said neck in said well and with said valve open whereby a barometric feed is provided to maintain a substantially constant level of solvent insaid container.

l5.-A sealing machine a defined in claim 7 in which said solvent applying means comprises a container, spaced partitions in said container, opposed vertical slots in said partitions, a solvent applying roller having a shaft removably received in said slots with the lower portion of said roller immersed in solvent in said container and with the upper portion of said roller above the level of the solvent, a second roller rotatably mounted on said partitions with the lower portion of said second roller below the upper portion pos'ition 'with' said neck in said well and with said valve'open whereby a barometric feed is provided to maintain a substantially constant level of solvent in said container, 7 16. A'sealing'machine as defined in claim 7 which sa'idsolvent applying means comprises 'a cemamer, a solvent applying roller rotatably ted in said container with the'lower por- {t1on"of said' roller'immersed insolvent in'said container and with {the upper 'portion' of "said roller above the level of the solvent, a second roller rotatably mounted in said container with the lower portion of said second roller below the upper portion of said applying roller whereby tape passing over said applying roller and under said second roller will be held in firm engagement with said applying roller to receive solvent therefrom, a well adjacent said container, a channel communicating with said container and said well, a solvent reservoir having a filling and discharge opening formed by a neck, a valve disposed in said neck for closing the same, resilient means for biasing said valve to closed position and 7 means to open said valve, said reservoir being disposed in inverted position with said neck inv said well and with said valve open whereby a barometric feed is provided to maintain a substantially constant level of solvent in said container. V

17. A sealing machine as defined in claim 7 in'which said solvent applying means comprises a container, a solvent applying roller rotatably mounted in said container with the lower portion of said roller immersed in solvent in said container and with the upper portion of said roller above the level of the solvent, means to maintain tape in firm engagement with said applying roller to receive solvent'therefrom, a well adjacent said container, a channel communicating with said container and said well,,a solvent reservoir having a filling and discharge opening formed by a neck, a valve disposed in said neck for closing the same, resilient means for biasing said valve to closed position and means to open said valve, said reservoir being disposed in inverted position with said neck in said well and with said valve open whereby a barometric feed is provided to maintain a substantially constant level of solvent in said container.

w 18. A sealing machine as defined in claim '7 in which said solvent applying means comprisessaid well whereby a barometric feed is provided to maintain a substantially constant level of solvent; in said container.- I 7 :194A sealing machine as defined. in claim '7 in which said solvent applying meansv comprises a container, a solvent applying roller rotatably mounted in said container with the lower portion of said roller, immersed in solvent in said container and. with the upper. portion of said roller above the level of the solvent, means to maintain tape in firm engagement withsaid applying roller to, receive solvent-therefrom and meansto maintain substantially constant level of solvent in saidcontainer.-

20. A sealing machine as defined. in claim 6 inwhich the means for removing excess solvent from the tape comprises a rod of irregular cross section disposed-in the path of movement of tape of said solventrapplying means, a relatively sharp edge onone side of'said rod and a smooth surface on the opposite side and'means to adjust said rod. to selectively engage said sharp edge or said smooth surfacexwith saidtapeto vary the wiping action whereby excess solvent is removed from saidtapa.

JAMESM.

JOHN JOSEPH GREVICH.

REFERENCES CITED a The following references are of record: in'the file of this. patent:

UNITED STATES lATENTS I Date Number -Name 1,115,828 Johnston "Nov. 3; 1914 1,195,310 v 7 White et a1. Aug. 22, 1916 1,638,664 Greenfield Aug. 9, 1927 2,003,337 Brady et 1 June 4,1935 2,126,908 Moore Aug..16, 1938 2,244,282 Bergstein June 3, 1941 2,495,680 Andrews Jan. 21, 1950

Claims

1. A SEALING MACHINE FOR FORMING A SEAM BETWEEN TWO SHEETS OF THERMOPLASTIC MATERIAL COMPRISING IN COMBINATION A FRAME, A WORK TABLE ON SAID FRAME FOR SUPPORTING SUPERIMPOSED SHEETS TO BE JOINED WITH TWO ADJACENT EDGES IN SUBSTANTIAL ALIGNMENT, CONVEYOR MEANS ASSOCIATED WITH SAID TABLE FOR FEEDING SAID SHEETS LONGITUDINALLY THEREOF, SPACED SUBSTANTIALLY PARALLEL HOLLOW SHAFTS JOURNALED IN SAID FRAME ONE ABOVE THE OTHER, A SEALING ROLL FIXED TO ONE END OF EACH SHAFT ADJACENT AN EDGE OF SAID TABLE, MEANS FOR DRIVING SAID ROLLS COMPRISING A MOTOR AND A VARIABLE SPEED TRANSMISSION, TREADLE MEANS MOUNTED ON SAID FRAME FOR CONTROLLING THE OUTPUT OF SAID STRANSMISSION WHEREBY THE SPEED OF ROTATION OF SAID ROLLS MAY BE INFINITELY VAIRED BETWEEN ZERO AND MAXIMUM, MEANS ON ONE OF SAID ROLLS FOR DRIVING SAID CONVEYOR IN SYNCHRONISM THEREWITH, A HEATING ELEMENT DISPOSED IN EACH ROLL, SLIP RINGS FIXED ON SAID SHAFTS AND BRUSHES IN CONTACT THEREWITH, CONDUCTORS CONNECTED TO SAID HEATING ELEMENTS AND SAID SLIP RINGS AND EXTENDING THROUGH SAID HOLLOW SHAFTS WHEREBY ELECTRICAL ENERGY MAY BE SUPPLIED TO SAID HEATING ELEMENTS, A RELAY CONNECTED IN AN ELECTRICAL SUPPLY CIRCUIT FOR SAID HEATING ELEMENTS, AN ADJUSTABLE THERMOSTAT DISPOSED IN ONE ROLL AND CONNECTED THROUGH SAID SLIP RINGS TO SAID RELAY WHEREBY THE TEMPERATURE OF SAID HEATING ELEMENTS MAY BE CONTROLLED, MEANS FOR ADJUSTING SAID THERMOSTAT, MEANS FOR PERMITTING MOVEMENT OF ONE ROLL AWAY FROM THE OTHER, ADJUSTABLE YIELDABLE MEANS FOR BIASING SAID ROLLS TOWARDS EACH OTHER WHEREBY THE PRESSURE APPLIED TO WORK THEREBETWEEN MAY BE VARIED, MEANS FOR SUPPORTING A SUPPLY OF THERMOPLASTIC BINDING TAPE ON SAID FRAME, TAPE-PULLING MEANS DRIVEN BY SAID SEALING ROLL DRIVE MEANS IN SYNCHRONISM THEREWITH, MEANS FOR RENDERING SAID TAPE-PULLING MEANS OPERATIVE OR INOPERATIVE IN ACCORDANCE WITH THE TENSION IN THE TAPE FED THEREFROM, MEANS FOR APPLYING SOLVENT TO ONE SURFACE OF SAID TAPE, MEANS FOR REMOVING EXCESS SOLVENT FROM SAID TAPE, MEANS FOR LONGITUDINALLY FOLDING SAID TAPE UPON ITSELF AND APPLYING THE SAME OVER THE EDGES OF SAID SHEETS TO BE JOINED WHEREBY UPON PASSING BETWEEN SAID SEALING ROLLS SAID SHEETS WILL BE JOINED TO SAID BINDING TAPE UNDER THE ACTION OF HEAT AND PRESSURE TO FORM A CONTINUOUS SHEET.