US2520322A - Mechanism for mounting sheet material on backing sheets - Google Patents

Description

Aug. 29, 1950 L. MESTRE 2,520,322 MECHANISM FOR MOUNTING SHEET MATERIAL 0N BACKING SHEETS Filed Oct. 25, 1945 s Sheets-Sheet 1 v .36 FIG. 2. 37 35 INVENTOR. LU l S M E ST RE HA5 ATTORNE) Aug. 29, 1950 L. MESTRE 2,520,322

mzcamusm FOR MOUNTING SHEET MATERIAL on BACKING SHEETS Filed Oct. 23, 1945 3 Sheets-Sheet 2 FIG. 3.

' INVENTOR. '75:! LUIS ME STRE HA5 ATTORNEY Aug. 29, 1950 L. MESTRE 2,520,322

MECHANISM FOR MOUNTING SHEET MATERIAL 0N BACKING SHEETS 3 Sheets-Sheet 5 Filed Oct. 23, 1945 INVENTOR. LU I S M E S T R E HA5 ATTORNEY Patented Aug. 29, 1950 UNITED STATES PATENT OFFICE MECHANISM FOR MOUNTING SHEET MATERIAL ON BACKING SHEETS Luis Mestre, New York, N. Y.

Application October 23, 1945, Serial No. 623,917

7 Claims. (CL 270-58) The present invention relates generally to mechanism for mounting sheets of desired characteristics on backing sheets or the like and more particularly to a machine for automatically mounting stencil sheets on backing sheets as long as the requisite material is supplied.

Heretofore, such mounting of stencil or other sheets on backing sheets has been effected largely by manual operations. invention all necessary operations are carried out automatically and production will be accelerated substantially.

An important object of the invention is to provide a novel and advantageous machine adapted to carry out automatically work of th character specified.

Another object of the invention is to provide a novel and advantageous machine for assembling According to the present and securing together pairs of sheets wherein two sheets at least one of which has adhesive material at one face thereof are brought edgewis into position one above the other but spaced apart and then they are moved into contact with each other and pressed together to render said adhesive effective.

Still another object of the invention is to provide a machine of the character specified wherein as soon as a sheet is mounted on a backing the assembled parts are shifted to another position.

Yet another object of the invention is to provide apparatus of the character specified wherein a pile of sheets to be mounted is raised the thickness of a sheet thereon after each removal of a sheet from the top thereof and a pile of backing sheets is raised the thickness of a backing sheet each time a backing sheet is removed from the top thereof.

According to one manner of carrying out the invention, sheets to be mounted such as stencil sheets are supplied in a pile or stack contained in a vertical chute which accurat ly positions the sheets. Said pile rests on a vertically movable table which is moved upwardly a distance equal to the thickness of one of said sheets. The uppermost sheet is below the top of the chute and one of the walls in contact with the ends of the sheets is outturned to support the head or top portion of a baclnng sheet which is longer than the stencil, and then upturned to position the backing sheet accurately. Each of the backing sheets is provided at its head or top end with a series of perforations, preferably in the form of keyhole slots, and when a backing sheet is in position over the pile of stencil sheets said perforations thereof lie above said shelf and slots therein which extend through said upturned portion.

At a side of said chut engaging the sides of the stencil sheets, there is a generally horizontal feed table over which backing sheets are passed to the top of the stack of stencil sheets. This table is higher than the uppermost stencil sheet in the stack and between the table and the top of the stack there is provided a downwardly inclined guide which may be formed by properly inclining the corresponding side of the chute and the table near its adjacent edge. At the outer side of said table there is an upright backing sheet chute in which a stack of downwardly facing backing sheets is supported with the uppermost backing sheet in position to be fed edgewise to the feed table. The stack of backing sheets rests on a table in said chute and each time a backing sheet is fed from the top of the stack, this table is raised a distance equal to the thickness of one of said backing sheets.

Each backing sheet is fed from the top of the stack by a feed device synchronized with other parts of the apparatus. Each sheet thus fed to the top of the feed table is grabbed by upper feed rollers and lower feed rollers and fairly thrown along the upper surface of said feed table intoengagement with the opposite side of the stencil sheet chute. As each backing sheet crosses the feed table, adhesive is applied to its face along a transverse zone which will li above the adjacent end of the uppermost stencil sheet.

The adhesive on the backing sheet must not engage the adjacent stencil sheet during the travel across the stencilsheet chute. To this end provision is made of fingers passing through the opposite wall of the chute, projected over the stencil sheet stack to receive the backing sheet thereon and then withdrawing. As soon as said fingers are withdrawn, a roller is advanced from said opposite side of the chute over the upper surface of the backing above the zone provided with adhesive and then withdrawn.

As soon as the pasting action is completed, the backing sheet is picked up by its upper end, carried across the stencil sheet chute and deposited face up on a vertically-movable inclined table or a stack thereon. The inclination of the table prevents the assembled sheets from working outwardly and makes it feasible to use a chute with an open outer side thus facilitating removal of stacked material therein. This transfer-of individual sheets with stencil sheets attached thereto may be effected by means including an oscillating arm swinging about a pivot parallel to the. discharge side of the stencil sheet chute.

Substantially at the time a pasting operation is completed, the free end of the transfer arm is at the opposite side from the pivot.

Pivotally mounted on the free end of the transfer arm is a member parallel to the axis about which the transfer arm swings and having pins adapted to enter the slots in the shelf and the large parts of the keyhole slots and then after passing into the various ends of said keyhole filgl 151; the backing sheet and attached 3 stencil sheet, swing these assembled sheets over to the other side of the stencil sheets and deposit them on the stack or table at that position. Of course the positioning of the fingers must be effected by other means.

Other objects, advantages and features will appear upon consideration of the following detailed description and of the drawings, in which Fig. 1 is a plan view illustrating one embodiment of the invention, parts being broken away to show the underlying structure;

Fig. 2 is a section taken along the line 2-2 of Fig. 1;

Fig. 3 is a side elevation of the structure of Fig. l as viewed in the direction of the arrows at the end of line 33;

Fig. t is a section on the line 1-5 of Fig. 1;

Fig. 5 is a section taken along the line 5-5 of Fig. 3;

Fig. 6 is a fragmentary section taken along the line 66 of Fig. 3;

Fig. 7 is a fragmentary sectional view of the structure at the free end of the transfer arm; and

Fig. 8 is a fragmentary view showing details of structure at the free end of the transfer arm.

Referring to the drawings, there is illustrated an embodiment of the invention paticularly adapted to attach stencil sheets H! to backing sheets ll, each of which may be provided at one end with openings l2 preferably in the form of keyhole slots. At starting there is a pile or stack of stencil sheets one. platform or table 53 vertically movable in a guide-way or chute l8 having front and rear walls and H5 respectively, and side walls H which maintain the stencil sheets in proper position one above another. Also at starting there is a pile or stack of downwardly facing backin sheets on a platform or table I8 movable in a guideway H].

A backing sheet fl is fed from the top of the stack on table is by means of a device reciprocating over the top of this stack and comprising one or more feed rollers 26 resting on the uppermost backing sheet and turning freely in their non-feed movements. These rollers are held against rotation in their opposite or feed movements and in each of these movements feed the top backing sheet over an intermediate table 2| to feed rollers 22 which feed the sheet rapidly into position over the stack of stencil sheets it.

In its movement over the table 2! the backing sheet passes beneath rollers 23 and over a roller 24 which dips into a paste receptacle 25 and applies a band of paste to theface of the backing sheet near the line of perforations. Rollers 22, and the first roller 23 may be on one shaft 26 and the paste roller 24 may be on a shaft 21, the shafts 2c and 27 being operated at the proper speeds by a motor 28 acting through suitable speed reducing means 29. The second roller 23 is also operated by motor 28.

The rollers 22 throw each backing sheet ongaged thereby to a position over the stack of stencil sheets, against wall is and between lower fingers 33 and upper fingers which assist in properly positioning the backing sheet over the uppermost stencil sheet. Said lower fingers prevent the paste on a backing sheet if from engaging the uppermost stencil sheet as it passes to a position thereover. Said upper fingers 3 5 are inclined downwardly from their free ends and act to knock down on the lower fingers 33, each sheet fed thereto by the rollers 22. The stencil sheets If are shorter than the backing sheets H and the guideway or chute I4 is correspondingly smaller in horizontal section than the guideway it. The arrangement is such that the bottom end of the backing sheet will be positioned directly over the bottom end of the uppermost stencil sheet and the upper perforated end of the backing sheet will extend beyond the upper end of the top stencil sheet and overlie a narrow horizontal shelf or table 35 having at its outer edge a vertical flange 3t to aid in positioning the backing sheets over the uppermost stencil sheets. As indicated in Figs. 2, 3 and 4, the table 35, the top stencil sheet if) and the fingers 33 are at a lower level than table 2|. It is therefore necessary to have each backing sheet if knocked down by fingers 34. There is a downwardly inclined supporting surface between the table 2! and the top of the wall 55. This inclined support may be designated as 2 ia.

At this stage of the operation the backing sheet over the stack of stencil sheets is supported by the fingers 33 and by the table 35. The fingers 33 and 34 are then withdrawn and a roller 31 at the free end of a pivoted arm 38 is moved over the upper surface of the backing sheet above said band of paste, toward the stack of backing sheets and then in the opposite direction off the backing sheet. In this reciprocation the band of adhesive material on the backing sheet will be pressed against the upper end of the top stencil sheet and the two sheets will be pasted together.

The backing sheet with the attached stencil sheet is then picked up by fingers 39 entering certain perforations or openings 12 and moving upwardly through slots 35a in table 35 and communicating slots 36a in vertical flange 36. Said fingers 39 are part of a suitable transfer device adapted to swing the perforated end of the backing sheet over to the other side of the machine and deposit the assembled sheets in turned over position on a table 40 movable vertically in a guideway or chute M. Preferably said table 40 is inclined upwardly toward its outer edge and the chute 4| is open at the corresponding side, thus facilitating removal of the mounted sheets. The fingers 33 and 34 are then returned to their positions over the stack of stencil sheets preparatory to receiving another backing sheet.

The operations thus described in general for a single backing sheet and a corresponding stencil sheet will be repeated until it becomes appropriate to replenish the stack of backing sheets and/or stencil sheets, or to stop the machine for other reasons. In this connection it may be said that the hacking sheet table I 8 and the stencil sheet table I 3 are moved upwardly during the operation of the machine and the table 4'!) is moved downwardly, to maintain the tops of the stacks or piles at the proper levels.

The feed rollers 22 are rotated at high speed and throw a sheet advanced thereto, into position over the stack of stencil sheets and between said lower fingers 33 and upper fingers 34 which are positioned over the stencil sheet stack at that time. It will be evident therefore that feeding of the backing sheets to the stencil sheet stack at proper times depends upon proper timing of the feed by the feed rollers 29. Said rollers 20 have friction surfaces which may be of rubber and are mounted on a shaft 42 to which they are connected by one way clutch mechanism which may be of known construction. This shaft 22 may have its ends fixed in sides 43 of a Ushaped frame at the end of an arm 44 projecting from a shaft carried by arms 46 pivoted at 41 on frame members 48 at opposite sides of the frame. This backing sheet feed mechanism is substantially the same as mechanism heretofore in use. An example of this feed mechanism is shown in my prior Patent No. 2,233,895, March l, 1939.

In the machine herein disclosed the arms 4'5 are swung about their pivots ll by means including an arm 49 constituting a downward extension of one of said arms 46 and having at its lower end a pin-and-slot connection with one end of a forwardly and rearwardly extending link 50 mounted for longitudinal movement. At its other or rear end, the link is connectedby a short link 5| to again 52 eccentrically mounted on a vertical shaft 53 as by means of an arm E i fixed on the lower end of said shaft.

The shaft 53 is driven by means including a bevel gear 55 fixed thereon and meshing with a bevel gear 56 at the rear end of a horizontal shaft 51 which as brought out more fully hereinaftermay be considered the main shaft of the machine. Fixed on said shaft is a grooved pulley 58 which is connected by means of. a suitable belt 59 to a smaller grooved pulley driven by a motor 6! mounted in the lower part of said frame. The belt and pulley construction just described constitutes speed reducing means and a speed reducer 62 may be interposed between the motor 6| and pulley 60.

The link 58 may also be utilised to raise the stencil sheet table [3 and the backing sheet table I8, and lower the table All on which the backing sheets with attached stencil sheets are deposited. Each of said tables is supportedby means inelud ing a vertical member 63 having its upper end secured to the bottom of the table and having an axial screw-threaded bore receiving a rotatable externally screw-threaded member 54 which is supported by the frame of the machine against downward movement. Each member 63 may be held against turning about its vertical axis as by making it with a square, external cross section and slidable through a square hole in a fixed member.

Fixed on each externally screw threaded mem ber 64 is a ratchet wheel 55 operable by a pawl :35 pivoted on an arm 6'! mounted to swing about the axis of said member 5t. Each arm 6? is operated by means of a link 58 pivoted at one end to said arm and at the other end to link 5?. The drivingof the ratchet wheel 555 may be regulated by means of a pin-:and-slot connection between arm 61 and link 58. It will be seen however, that with the disclosure in Fig. 6, the screw threads of the supporting members for table n! would have to be in a direction opposite to those for the other tables in order to lower it concomitantly with the raising of the other tables. The different rates of feed for the different tables may be provided for in various ways, for example by using screws of different pitch or by giving different movements to the arms carrying the pawls.

The vertical shaft 53 is connected at its top, by a bevel gear connectionutsa, to a transverse horizontal shaft 69 which serves through suitable intermediate means to reciprocate thelower fingers 33, the upper fingers 3t, and the roller 3'! which completes the pasting of the stencil sheets to the backing sheet. The lower fingers 33 are attached at one end to a transverse bar or member 10 at the bottom thereof and the upper fingers 34 are attached to said bar at the top there of. Grooved wheels ll are pivoted onopposite ends 'of said bar 19 and run between pairs of. rods 72 supported at opposite ends in the frame. Of

.the fingers 33 and 34' the lower fingers 33 extend through openings in a plate 73 carried b the frame at the rear of the guideway for the stencil sheets.

The upper fingers 34 which turn upwardly toward their forward ends pass through notches or cut-outs in the upper part of said plate 73. Such upward turning of fingers 3d assures the entrance of a backing sheet between the sets of fingers, directs the sheet downwardly, and also exerts a checking action on sheets fedthereto by the feed rollers 22.

The bar 10 may be reciprocated along said rods or guides 12 by means of a link 14 pivoted at one end to the bar 10 at its middle and at the other end to the upper end of a lever 15 of which the lower end is pivoted on a cross shaft 15a of the machine. The lever '15 is actuated through a link is pivotally attached to the lever at an intermediate point thereof and pivotally attached to the lower end of a lever ll pivoted at its upper end to thefixed frame. As illustrated, the lever T! is offset at its middle portion to extend around the shaft 69 and thus economize space. Mounted on said shaft 69 is a cam disk is having at one face a suitable cam groove 19 to receive a cam follower or pin 86 projecting from the side of the lever Tl. i

The arm 38 carrying the roller 31 at one end extends through an opening in plate l3: and is connected at its other end to a member 82 provided at its ends with grooved wheels 83 engaged by rods 84 above and below the same to provide guideways therefor. Thismember 82 may also be reciprocated by a link M, a lever 15 pivotally mounted on cross shaft 15a, a link 16, a lever H, a cam disk 18a on shaft 59 and having a suitable cam groove lilo, and a cam follower or pin 83a. The cam groove 59a is so shaped that the roller 31 is not moved over the backing sheet until the latter has been placed over the stencil sheet stack between the upper and lower fingers 33 and 34 respectively and said fingers have been withdrawn. After completing this movement the roller 31 is retracted.

The shaft 5! which has at its rear end a driving connection with said vertical shaft 53, is supported in suitable bearings 85 and near its forward end it carries an eccentric pin 85 as by means of an arm 81 mounted firmly on the end of the shaft.

Said eccentric pin 85 is utilized for operating mechanism by which each unit consisting of a backing sheet and a stencil sheet pasted thereto. is swung from the top of the stencilsheet stack and deposited face upward on the platform or table 48. To this end the pin as projects into a radial slot 88 in a member or arm 89 projecting downwardly from a shaft 99 on which it is fixed.

As illustrated the axes of the shafts 51 and 9!] (Fig. 5) are parallel and located in the same vertical plane. is rocked about its axis. This rocking movement is transmitted from shaft 90 to a shaft 9! directly above the same by means of a gear 92 on shaft 93 and a smaller gear 93 on shaft9 l. Fixed on the shaft 9! is a transfer arm or frame 94 which is swung back and forth between an upright position above shaft 9! and a generally horizontal position across the machine. Said transfer frame 94 may take many different forms but as shown in its pickup position (Fig. 5) has a straight top portion 95 extending across the As the shaft 5'! turns, the shaft 96.

machine, an end portion 96 extending downwardly to shaft 9I to which it is fixed, and at the opposite end a downwardly extending end portion 91 to carry a suitable device including said fingers 39, for picking up backing sheets to which stencil sheets have been pasted.

Said fingers 39 are carried by a sleeve 98 mounted on a rod or shaft 99 projecting from the free end of end portion 91 of th transfer frame 94. Said sleeve 98 may be held by any suitable means against movement off the end of said rod .99. As illustrated the fingers 39 comprise arms I projecting from said sleeve and pins IOI projecting from said arms I00 and "coaxial therewith. Extending from said sleeve 98 at the side opposite to said fingers 39 is an arm I02 carrying a counterweight I03 projecting from the side thereof and preferably cylindrical in shape.

Normally said counterweight I03 will act on saidsleeve 98 to hold an arm I04 projecting therefrom against a pin I05 at the right in Fig. 5, as indicated in dot-and-dash lines directly above the stencil sheet stack. This pin I05 projects from a plate I03 fixed on the free end of portion 91 of the transfer frame or arm. Said plate I06 is shown in complete form in Fig. 8 and in other figures as partially broken away. Rocking movementof said sleeve 98 to swing said arm I04 away from said pin I 05 is limited to prevent overthrow, by engagement of arm I04 with a pin I01 corresponding to pin I05. Also fixed on said sleeve is the base portion H08 of an arm I09 having an end part or flap IIO (Fig. '7) hinged at pivot III to said base portion or base I08. This hingeis constructed so that flap I I0 cannot be turned counterclockwise (Fig. 5) beyond the straight line position with reference to base portion I08. The flap can, however, be turned in the opposite direction about said pivot against the action of a spring I I2.

As the transfer frame swings downwardly in the clockwise direction (Fig. 5) the fiap H9 moves downwardly along the outer arcuate surfaceof a guide I I3. During the movement alon said arcuate surface the flap III is held away therefrom until, as the transfer frame reaches its lowermost position, the counterweight I08 engages a concavely curved upper surface of a cam IM and the arm I04 is swung counterclockwise toward pin I97 on plate I06. As the arm IE4 comes close to the pin I01, the transfer frame reaches the lower limit of its movement and further movement of arm I04 toward pin I0! will be overthrown due to inertia.

However, as the sleeve 98 moves in counterclockwise direction (Fig. 5) at this time, said flap H0 will engage 'said arcuate surface of guide I I 9 and be turned back until it passes the lower end of said guide and snaps to its original position with reference to the base portion I08 of arm I09. Then on the upward movement of the transfer frame, the flap rides along said arcuate surface and keeps the fingers 39 in substantially their leftward limiting positions with arm I0 3 against pin I01 until the flap passes off the upper end of the guide. During this movement the pins IiiI at the outer ends of fingers 39 pass upwardly through the slots in the table 35 and vertical flange 38 and the points of the pins enter the large ends of the keyhole slots in the backing sheet over the stencil sheet stack. As the pins rise the inclined body portions eventually engage the ends of the narrow portions of the slots and then lift the righthand end of the backing sheet and the-attached stencil sheet.

As the flap I I0 moves off the upper end of guide II3, the sleeve 98 is turned clockwise (Fig. .5) by the counterweight I03 until arm I04 strikes pin I05 on said plate I06. The backing sheet and attached stencil sheet are swung upwardly about the left edge of the backing sheet as indicated by the intermediate position (Fig. 5) of the transfer frame. As the transfer frame approaches the left end of its path, the flap I I0 strikes the upper end of a trip member II5. Such engagement causes sleeve 98 to be turned in a counterclockwise direction. The movement of the transfer frame is halted before the arm I04 engages pin I0! but the momentum of the swinging parts causes the arm I04 to swing into position against the pin 801. At this stage the pins 'I 0 I are pointed downwardly so that the backing sheet transferred thereby is freed and swings downwardly and to the left until it falls on the stack carried by table 40.

It should be understood that various changes may be made and that certain features may be used without others, without departing .from'the true scope and spirit of the invention.

What I claim is:

1. In a machine of the character specified, means for supplying in succession at a predetermined position single sheets to be backed, means for supplying backing sheets in succession at a second predetermined position, means for applying adhesive to one of two sheets to be assembled and superimposing the two sheets by relative edgewise movement thereof, means for preventing during such relative edgewise movement contact of adhesive on one sheet with the other sheet and means for pressing the two sheets together to render the adhesive effective, means for removing each pair of attached sheets, turning it over and delivering it at a predetermined position, said last-mentioned means including sheet-holding means supported to travel in an orbit which traverses one edge of the attached sheets assembly and substantially about the other edge of said assembly as an axis, and means for rendering said sheet-holding means effective at said first-mentioned edge.

2. In apparatus for successively mounting sheets on longer backing sheets, a vertical chute containing a pile of downward facing sheets to be mounted, means including a table supporting said pile of sheets for raising said pile when sheets are removed from the top thereof, means for feeding backing sheets one by one edgewise to a position over said pile, means in the feed path of said'backing sheet for applying adhesive thereto along a transverse zone near its upper end, means for spacing said backing sheet from said pile while moving it to overlie said pile and then dropping it on the uppermost sheet of said pile with the adhesive over the upper end of the sheet, means for pressing each backing sheet against the top sheet of said pipe to render the adhesive effective, means to receive backing sheets on which other sheets have been fastened, and means effestive when a backing and other sheet have been fastened together to pick up the exposed head end of said backing sheet and by turning the backing sheet around its lower edge deposit the united sheets in inverted condition in such receiving means, said last-mentioned means including sheet holding means supported to travel in an orbit which traverses one edge of the attached sheets assembly and substantially about the other edge of said assembly as an axis, and

means for rendering said sheet-holding means effective at said first-mentioned edge.

3. In apparatus for assembling with backing sheets other sheets requiring backing, comprising means for supporting in registration a pile of sheets to be backed, means for feeding backing sheets one by one edgewise to a position over said pile, means in the feed path of said backing sheet for applying adhesive to the underside of each sheet along a transverse zone near its upper end, means for directing said sheet downwardly over said pile, means under said directing means for spacing said backing sheet from said pile, in a position overlying the same comprising supporting fingers movable longitudinally in one direction in a horizontal plane to a position to prevent contact of the adhesive with the sheet to be mounted during the feeding movement and in the opposite direction to permit said backing sheet to fall into contact with the top sheet of said pile, means for pressing each backing sheet against the top sheet of said pile to unite the two sheets, and means to remove from the top of said pile each pair of attached sheets, said last-mentioned means including sheet-holding means supported to travel in an orbit which traverses one edge of the attached sheets assembly and substantially about the other edge of said assembly as an axis, and means for rendering said sheet-holding means effective at said first-mentioned edge.

l. In apparatus of the class described, a vertical chute containing a pile of sheets to be backed, the side of the chute at one end of the uppermost sheet being oifset to form a horizontal shelf to receive the head end of a backing sheet of greater length than the sheets in said chute and attached to the adjacent end of the uppermost sheet and upturned at the outer side of said shelf to position the corresponding end of a backing sheet, said backing sheet having a line of perforations over said shelf and said shelf and upturned portion having communicating slots corresponding in position to said perforations, and means to pick up the perforated end of said backing sheet and deposit it in turned over position at the opposite side of said chute comprising an arm oscillating about an aXis at the opposite side of the chute and carrying at its opposite end a device adapted to rock about an axis parallel to said axis of oscillation, said device having pins to enter said perforations, and means to control said device to hold said pins away from the perforated end of the backing sheet in its downward movement and to cause said pins to enter said perforations in the reverse movement to carry the backing sheet over to the other side and then release the same.

5. In apparatus of the class described, a vertical chute holding in vertical alignment a pile of horizontally positioned sheets to be backed, a table at the foot of said pile and means for raising said table the thickness of one sheet after an uppermost sheet has been removed, the uppermost sheet being below the top of the chute, the chute wall at one end of said sheets extending outwardly at the level of'said pile to form a shelf to support the head end of a backing sheet of greater length than the sheets in the pile and an upright end to determine the position of the corresponding end of a backing sheet, means for attaching the end of said uppermost sheet to said backing sheet, each of said backing sheets having a row of openings in the part over the shelf and said shelf and said upright having connected slots.

6. The combination according to claim 3 wherein the means for positioning the backing sheet including a second set of fingers above the supporting fingers and movable back and forth therewith, said fingers of the second set being flared upwardly from the supporting fingers to direct the advancing backing sheets down to the supporting fingers.

7. In apparatus of the class specified, a chute containing a pile of sheets to be backed, a support for said pile, means for raising said support each time an uppermost sheet is removed, a chute wall having an offset to act as a guide for the extended end of a backing sheet of greater length, means for supplying at the top of said chute a backing sheet with a band of adhesive on its lower face and near its head and pressing means to render said adhesive effective to unit said sheets, said offset portion being slotted to its upper edge, and means for removing the pair of united sheets and depositing it in inverted condition at another position, comprising a pick-up device and means to render said pick-up device effective to pick up the projecting end of the backing sheet at said slotted offset portion and to render said pick-up device ineffective as the united sheets approach the deposit position.

LUIS MESTRE.

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

UNITED STATES PATENTS Number Name Date 1,440,856 Westcott Jan. 2, 1923 1,893,523 Radzinsky Jan. 10, 1933 2,164,371 Ajello July 4, 1939 2,166,388 Bergstein July 18, 1939 2,260,540 Schramm Oct. 28, 1941 2,384,768 Rau Sept. 11, 1945

Images