US2245836A

US2245836A - Sheet feeder

Info

Publication number: US2245836A
Application number: US329965A
Authority: US
Inventors: Stobb Anton
Original assignee: American Type Founders Co Inc
Current assignee: American Type Founders Co Inc
Priority date: 1940-04-16
Filing date: 1940-04-16
Publication date: 1941-06-17
Anticipated expiration: 1958-06-17

Description

June 17, 1941.

A. s'roBBK SHEET FEEDER Filed April 1e, 1940 3 Sheets-Sheet 1 NN mv SHEET FEEDER 4 Filed April 16, 1940 3 Sheets-Sheet 2 June 17, 1941. v A, STOBB l v '2,245,836

' SHEET FEEDER l Filed April 16, 1940 3 Sheets-Sheet 3 Patented June i7, 1941 SHEET FEEDER Anton Stobb, Westfield, N. J., assignor to American` Type Founders, Inc., Elizabeth, N. J., a corporation of New Jersey Application April 16, 1940, Serial No. 329,965

24 Claims.

This invention relates to methods and apparatus for feeding sheets, and more particularly to methods and devices of the kind adapted foruse in separating and forwarding individual sheets from a suitably supported pile of such sheets to printing presses, folding, slitting, gluing, or wrapping machines, or the like.

The general object of the invention is to provide a novel and improved sheet feeding mechanism which is adapted for operation at high speed upon sheets which may differ widely in size, thickness, quality, and material, without sacrice of accuracy orvpontro'l, and with a minimum of waste of either time or material. The improved feeder is of relatively simple and sturdy construction, which naturally facilitates its manufacture, operation and maintenance at low cost.

An important purpose of the invention is the provision of an improved feeder of the type which is equally well adapted to feed sheets from a pile, either singly and in spaced sequence, or in overlapping relationship, the latter method of feeding being known as stream feeding.

The advantages ofk stream feeding are well known, this method being pursued chieiiy in order to permit more rapid feeding of the sheets while maintaining perfect registration of the successive sheets at the impression cylinder of the printing press or at the end of the conveyor usually employed in connection with folding machines or the like. The number of sheets on the conveyor intermediate the separating and feeding device and the operating mechanism which is to ultimately receive the sheets is increased as compared with thenumber of sheets so located in the case of serial feeding, while at the same time synchronous action of the sheet separating and feeding means with respect to the sheet conveyor means is maintained, one sheet being withdrawn and carried off by the latter means for each sheet separated and fed from the pile by the rst mentioned means.

In practicing the stream feeding process, it has been found most desirable to seize or grip the successive top sheets of the pile at points adjacent their rear edges so that they may be separated from the pile and started on their forward movement onto the transfering conveyor without interference with the trailing end of the next preceding sheet which has not yet cleared the front edge of the pile, but is still in overlapping relationship to the forward or leading portion of the sheet being handled. It is also advantageous to combine the separating and forward feeding functions in a single instrumentality which is preferably a suction gripper capable of oscillatory movements having both longitudinal and vertical portions or components.

An important feature of the separating and feeding procedure is the ufling up of theupper rear portion of the pile of sheets as, for example, by means of a lblast or Winding device which serves to separate a number of the uppermost sheets of the pile by the interposing of layers of air between the individual sheets adjacent their rear edges. This winding of the sheets not only aids in preventing the sheets adhering one to the other by reason of charges of static electricity or the interlocking of marginal burrs at their cut edges, but also serves to somewhat raise the top`sheets of the pile toward the gripper element, whereby it may be more readily engaged bythe gripper so that the latter need not` descend solidly into contact with the pile in order to seize the sheet. 'Ihis is also of advantage in making unnecessary an extremely accurate setting of the pile height gauge, especially in cases where .the pile of sheets being acted upon is of uneven height. The air blast, which may be'maintained in continuous operav tion, also functions to iioat each sheet as it is forwarded to the conveyor after separation from the.pile.

With the overlapping of the sheets at the front edge of the pile `during stream feeding, and the iiufflngv and floating of the loosened rear edges of the uppermost sheetswith the consequent elimination of pile engaging or pressure devices at the latter point-there exists more than ever the necessity for making provision for preserving the general shape and position of the upper portion of the pile and preventing disalignment of the sheets' and the feeding of more than one sheet at a time. The arrangement of mechanism in accordance with this process of feeding also places some limitation on the available locations for a pile height gauge. These problems are solved, however, in this particular type of feeder, by' the provision of a combined hold-down or presser member and height gauge finger at the front edge of the pile adjacent the mouth of the transfer conveyor which carries the stream of overlapping sheets from the feeder to the press or other machine being fed.

The placement of the hold-down member at this point makes it necessary to move each suiccessive top sheet of the pile rearwardly for a short distance to withdraw its forward edge scribed in detail.

from beneath the hold-down during its separation or removal from the pile and before the sheet is finally fed forwardly onto the conveyor. The application of these alternate rearward and forward movements by means of the novel unitary separating and feeding device, without sacrifice of speed or smoothness of operation, is gine of the principal objects of the present inven- In its preferred form, the invention contemplates the provision of a suction gripper mounted on a longitudinally extending guide carried by an oscillatory frame or feeder head supported above the top of the pile of sheets. Suitable driving mechanism is'provided for reciprocating the gripper along the guide in synchronism with the movement of the conveyor and that of the device to which the sheets are ultimately delivered. This driving means may conveniently comprise a system of cranks and linkages actuated by a rotary cam, the latter being so shaped as to regulate the forward and rearward speed of movement of the gripper and preferably to provide, in the cycle of movement, a period of dwell during which the gripper may be extended to seize a sheet and retracted to raise it above the level of the top of the pile.

The gripper member itself comprises a pneumatic cylinder having a differential piston reciprocable therein along a rearwardly and upwa'rdly inclined path, the piston being provided with a. hollow piston rod upon the lower end of which is disposed a flexible suction cup. The cylinder is adapted to be placed in communication with a source of vacuum'upon both sides of the piston, and the ratios of the area of the upper and lower surfaces of the piston and of the communicating passageways are such that the piston is moved downwardly toward the pile of sheets when suction is applied to the cylinder, and when the cup is sealed by the adherence thereto of a sheet, the piston is drawn upwardly and rearwardly into the cylinder.

By preferance the transmission is so designed that the dwell occurs at the rearward limit of movement of the gripper member, and at approximately this point, the suction cup is caused to descend toward the pile. Upon encountering the top sheet, the rear portion of which has been loosened from the pile by the air blast. the cup is sealed by the adhering sheet and the consequent inclined upward and rearward movement of the gripper cup causes the front edge of the sheet to be withdrawn from beneath the hold v down: and upon the forward movement of the `gripper member the sheet is fed over the holdgreat a curtailment of the horizontal component of movement of the gripper piston and suction cup, certain sheet guiding or confining means are provided. V

Other objects and features of. novelty;v including the improved method of sheet feeding, will become clearly apparent when the following specification is read in connection with the accompanying drawings. In the drawings, one illustrative or exemplary embodiment of the inventionis shown and will be hereinafter de- It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, but that various modifications, alterations, and rearrangements to suit varying conditions are contemplated, such as would occur to one skilled in the art to which the invention relates.

In the drawings,

Figure l is a view in longitudinal vertical section of the upper portion of a sheet feeder embodying the principles of-the invention, the feeder head and associated mechanism being shown for the most part in side elevation, and the sheet gripper being in its farthest rearward and upward position;

Figure 2 is a fragmentary horizontal sectional view on an enlarged scale and taken on line 2-2 of Figure 1;

Figure 3 is a transverse vertical sectional view on the same scale as Figure 2 and taken on line 3--3 of Figure 1;

Figure 4 is a vertical longitudinal sectional view taken substantially on linev 4--4 of Figure 3;

Figure 5 is a fragmentary detailed view in vertical transverse section taken on line 5-5 of Figure 4;

Figure 6 is a vertical central sectional view through the sheet gripper member;

Figure '7 is a sectional view of the gripper member taken on line 'I'| of Figure 6;

Figure 8 is a fragmentary view in side elevation of the feeder head in the immediate vicinity of the gripper member, and showing the gripper member in its rearward shifted position and the suction cup in its extended position;

Figure 9 is a similar view showing the gripper memberin its forward or delivery position with the suction cup retracted;

Figure l0 is a vertical longitudinal sectional view on a reduced scale of a detail of the feeder head; and

Figure 1l is a diagram of the cycle of movement of the suction cup under the preferred contlons of operation.

Referring more particularly to Figure 1 of the drawings, the sheet feeder will be seen to include the supporting frame I0, the two spaced side frame portions of which extend upwardly upon either side of the machine, one of them being indicated at II. Between the side frames there is disposed the pile elevator which-includes the platform I2 secured as at I3 to the elevator chains I4, and adapted tovsupport the pile board I5 upon which the pile P is supported. The elevator chains I4 are trained over a sprocket wheel (not shown) carried by the elevato' shaft I8. The shaft I8 extends from one of the side frames Il to the other, and is provided with a driving gear I9, the whole arrangement being conventional and forming no part of the present improvement.

A pile gauge 20 is provided at the front of the pile P and just rearwardly of the sheet forwarding conveyor C. The conveyor is preferably of the endless belt type and includes a roller 22 over which the belt 23 is adapted to run, and a drop roll 24 which serves to apply pressure to the successive sheets passing along the conveyor. Bearing upon the front edge of the pile is the hold-down member 25, which is provided with a tapered finger 28 overlapping the pile and a downwardly projecting abutment element 21 so disposed as to embrace the forward edge of the pileV of sheets. The hold-down member 25 is secured to the transverse shaft 25 and in order to enable the member 25 to perform the additional function of a pile height gauge the shaft 25' is connected by suitable mechanism (not shown) with the pile elevator driving device. One example of such a connection is illustrated in the `copending application of David P. Sanford, Serial No. 323,995, illed March 14, 1940, but within the scope of the present invention the pile height regulating mechanism may take any suitable form.

Above the longitudinal center line of the device there is supported-by means of the transverse shaft 29, the elevator shaft |8 and the cam shaft 30-the auxiliary frame A, which `in the present example comprises an elongated peripherally flanged casting provided at suitable points with apertured bosses providing bearings for the shafts referred to, and also providing means for supporting portions of the sheet'gripper actuating means. Secured to the lower portion of the frame A as by means of the screws or bolts 32 is the elongated longitudinally extending guide or track bar 35, along which the gripper supporting and actuating mechanism and the Winding del vice, are adapted to be moved to and from suitable positions with respect to the rear edges of the piles of sheet material to be fed.

The details of the gripper member and its associated mechanism are very clearly shown in Figures 2-7, inclusive, of the drawings. A substantially U-shaped bracket 36 provided with the arms 31 and 38 at the respective forward and rearwardends thereof is adjustably secured upon the track bar 35 which is adapted to be received within the spaced jaws 39 of thearms 31 and 38. Set screws such as indicated at 40 serve to secure the bracket rigidly in any adjusted position along the track bar 35.. As clearly shown in Figure 2 of the drawings, the main portion of the bracket 36 is spaced from the track bar 35, and there is disposed between these members the extensible gripper member indicated in its entirety by the numeral 45.

The gripper member 45 comprises a substantially cylindrical casing disposed at an angle to the horizontal and provided preferably adjacent its lower end with the slotted slide portion 46 which is adapted to embrace and ride upon the track bar 35. Operating mechanism is provided which includes the short link 48 pivoted as at 49 between the slide portion 46 and the spaced ear 50 of the member 45. The link 48 is pivoted at its forward end, as by means of the pin 52, between the bifurcations of the generally rearwardly extending arm 53 of the bell crank 54. The bell crank 54 is pivoted upon the pin 55 carried by the upwardly extending lug 56 formed on the bracket 36, and the forward arm 58 of the bell crank carries a pin 60 which has a slotted head 6| adapted to slidingly receive the parallel-motion operating bar 65.

'I'he bar 65 is adapted to be oscillated in a vertical plane while maintaining its horizontal position by means of the following mechanism. A forward bell crank 66 is pivoted to the frame A as at 61 and a corresponding rear bell crank 68 is pivotaily supported from the frame as at 69. Upwardly extending arms of these two bell cranks are connected for providing simultaneous operation by means of the link 10, and the respective rearwardly extending arms 1| and 12 of the bell crank 66 and 68 are pivotaily connected to the operating bar 85 as by the pin connection 14 and the pin and slot connection indicated at 15. The upwardly extending arm of the forward bell crank 66 is provided with a cam follower roller 11 which is adapted to be maintained in contact with the camv 80 carried by the cam shaft 30, as by means of a suitable spring, such as that indicated at 82 as extending between theupwardly extending arm of the rear bell crank 68 and a pin 83 on the frame A.

From .the foregoing it will be readily understood that rotation of the cam 80 in synchronism with the operation of the conveyor C and preferably with respect to the operation of the machine to which the sheets are being fed, causes the bell cranks 66 and 68 to oscillate and, through the pivotal connections, effects the vertical reciprocation of the parallel bar 65. It will be further understood that no matter where the adjusted position of the bracket 36 upon the track bar may be, the operating bar 65 is always received within the slotted head 6| of the element 60 carried by the arm 58 of the gripper actuating bell crank 54. Thus in every one of the adjusted positions, the vertical reciprocation of the bell 65, through the bell crank 54 and the link 48 will cause the gripper member 45 to move to and fro upon the track bar 35. This movement takes care of the fore-and-aft feeding and return movements of the gripper member 45 as a unit, but the sheet lifting provisions of the device have yet tobe described.

As most clearly shown in Figures 6 and 'I of the drawings, the body portion of the gripper member 45 is provided with a cylindrical chamber 85 inclined at substantially the same angle as said body portion. Arranged for reciprocation x 'clamped to the lower end of the tubular extension 89 as by means of the threaded flanged sleeve 92. Fixedly secured within the lower end of the cylindrical chamber as by means of the set screw is the guide sleeve 96 within which the piston rod 88 is adapted to reciprocate. This sleeve also serves to seal off theA lower end of the pneumatic cylinder from the atmosphere. The piston rod 88 is provided in its upper surface with a slot or groove 91 which is adapted to receive theV lower attenuated end of the set screw 95 which thus acts as a spline or key to prevent rotation of the rod 88 and thus maintain the cup continually in its vertical operative position. The sleeve 96 is shouldered to provide a seat for the relatively weak coil spring 98 which is compressed between the sleeve 96 and the lower face of the piston 86.

, In one of the side walls of the body portion of the gripper member 45, there is provided a bore or recess |00 into which a. nipple |0| is introduced and which is connected, as by means of the flexible hose |02, with a source of vacuum or reduced pressure diagrammatically indicated in Figure 'I at |05. In this communicating conduit |02 there is disposed a suitable valve means, also diagrammatically suggested vat |06, by which the application of suction to the gripper unit may be controlled and synchronized with the other moving parts of the feeder as by means of the connections indicated at |01. 'Ihe timing of the valve with relation to the .other mechanism for attaining The recess in the gripper 45 communi-A cates with Aa passageway ||0 which in turn is placed in communication with the cylindrical chamber 85, at a point beneath the piston 86 by means of the transverse passageway ||2. A restricted passageway ||4 provides communication between the passageway ||0 and the space ||5 at the upper end of the cylindrical chamber 05. From this space ||5 the hollow interior bore I |6 of the piston rod 80 leads to the suction cup 90.

From vthis description, -it will be obvious that when subatmospheric pressure is produced in the pneumatic connections leading into the gripper unit, the piston 86 will be drawn downwardly within the chamber 85 against the relatively weak pressure of the spring 30, due to the larger connections leading to the cylinder beneath the piston as compared with the restricted passageway I4 leading to the head of the chamber and also due to the fact that the space ||5 above the piston isat this initial point in the cycle, in communication with the atmosphere through the hollow piston rod and the unobstructed suction cup. The cup 90 is thus moved downwardly and forwardly with respect to the gripper cylinder and approaches the top of the pile P, the upper sheets of which have been fluied up and iioated' to some extent above the normal solid top of the pile, Upon contact of the suction cup 00 with the rear portion of the top sheet of the pile, the cup will be sealed by the sheet and the upper end of the cylinder will be cut oil from communication with thel atmosphere. Thus the vacuum or negative pressure will build up upon the upper side of the piston 06 which, now that the central bore of the piston is sealed oil?, is of an area considerably larger than the area of the annular under side of the piston, and the piston and the attached suction cup will rise within the cylinder to the initial upward and rearward position shown in Figure 1 and will be ready to start the forward feeding movement along the track bar 35 under the inuence of the cam 00.

The `winding device which is preferably continually. supplied with air under pressure is shown at |20 in Figure 1 of the drawings, the main body of the device being pivoted as at 2| to the lower rear portion of the longitudinally adjustable bracket 36. The upper portion-of the windingor blast attachment is adjustably' secured to the bracket 36 as by means ofA the hook |22, one end of which is threaded through a nut |23 pivoted as at |24 to the body oi' the winding device, The downwardly extending blast tube |25 is provided with a nozzle opening |26 directed toward the rear portion of the pilel P and provided with the hood |21 for confining the blast. f

It will be apparent at once that if the top sheet of the pile is raised excessively by the blast or winding means, the sheet will be seized by the suction cup before the piston begins to descend, or before it has descended to any great extent along its downwardly and forwardly inclined path. If the sheet is seized by the gripper at vsuch points, there will be either no rearward movement of the sheet before the sheet forwarding movement, or such rearward component would be insuilcient to completely withdraw the front edge of the sheet from beneath the hold-down. In order to insure that the descending movement of the cup is sufficient to provide, upon its return, the necessary horizontal `component to eil'ect the withdrawal of the sheet, there are provided guiding or limiting arms |20 which are pivoted as at |30 to depending lugs 3| secured at spaced points upon the transverse bar |32 carried by the'rear leg 30 of the adjustable bracket 36. The rear ends of the arms |20 are curved upwardly and are adapted to abut a portion of the bracket 36 as at |33 to serve to limit the downward movement of their forward ends. These arms are of suillcient weight to prevent excessive elevation of the sheets by means of the blast but are light enough to be easily raised by the successive sheets as they are lifted by the suction gripper.

A pair of resiliently mounted rearwardly disposed Jogger blades |35 are supported from the bracket 36 and are adapted to intermittently tap the upper rear edge of the pile of sheets to aid in preserving the alignment and proper position of the sheets. In order to support these blades |35 for horizontal movement the forwardly projectly rods |36 are provided, the rear ends of these rods being secured at spaced points to the cross bar |32, the blades |35 themselves are secured at their upper ends to the support |30 which is bent to provide forwardly extending arms |33 which terminate in inwardly bent portions |40; both the body portion of the element |30 and the inturned ends |40 being perforated to receive thev guide rods |36. Upon each of the rods |36 are disposed the spring stops |4|, and a coil spring |42 surrounds each of the rods |36 and is adapted to be compressed between the stops |4| and the inwardly bent ends |40 of the support |30. A right angled notch |45 is formed in the cylinder casing of the gripper member 45 near its lower end in order to provide a square surface to abut intermediate portion of the support |30 during the rearward movement of the gripper, and to move the member |30 together with the logger blades |35 rearwardly against the tension of the springs |42. The rearwardly displaced position of the blades |20 is shown in Figure 8 of the drawings. Upon the forward movement of the gripper member 45 the springs |42 are free to urge the blades |35 forwardly against the rear of the pile as indicated in Figure 9 of the drawings.

A complete cycle of operation of the feeder will now be described. In Figure 1 of the drawings, the gripper unit 45 is disposed at its extreme rearward position along the track bar 36, and the suction cup 00 carried by the piston 00 V)of the telescoping gripper member is in its rearwardly retracted position. In the preferred mode of operation of the device, suction is applied to the opening |00 of the gripper member at this point and cup 00 descends along its inclined straight line path downwardly and forwardly toward the rear portion of the top sheet of the pile. Upon contacting with the top sheet S, as shown in Figure 8 of the drawings, the

gripper cup is sealed by the sheet and the preponderance of suction upon the upper side of the piston causes the device to retract along the same diagonal upward and rearwardly inclined path and thus drawing the front edge of the sheet 0 rearwardly from beneath the hold-down wardly over the hold-down member toward the conveyor C. This forward movement is accompiished by sliding the gripper member 45 forwardly along the track bar 35 to the extreme forward delivery position shown in Figure 9 of the drawings. At this point the front edge of the sheet has passed over the upper surface of ,the hold-down member 25 and'has just entered the mouth of the conveyor C between the belt 23 and the conventional drop roll 24. At this point also the passageways of the gripper member 45 are cut off from communication with the source of vacuum and the sheet is released from the cup 90, Then as the larger portion of the cam 80 moves against the roller 11 the mechanism will be actuated to move the gripper unit 45 rearwardly upon the trackway 35 tothe position illustrated in Figure 1, however, without the sheet attached. Thereupon the described cycle of operation will be repeated and successive sheets removed.

From the foregoing description it will be seen that by means of the present invention there has been provided a novel and improved sheet feeder of simple construction and operation which is particularly adapted for the eillcient feeding of sheets, especially in accordance with the stream feeding method.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a pile board, comprising, in combination, a feeder head supported above the pile, a suction gripper movably carried by said feeder head, means for reciprocating said gripper ina straight line horizontally above the rear portion of said pile in a fore-and-aft direction and means actuated at a point in the cycle of horizontal movement for causing said gripper to descend toward the pile, seize a sheet, and then move diagonally upwardly again to raised position.

2. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a vertically movable pile board comprising, in combination, a hold-down member disposed at the forward edge of the pile and adapted to press resiliently upon the successive top sheets thereof, a feeder head supported above the pile, a suction gripper movably carried by said feeder head, means for reciprocating said gripper horizontally above the rear portion of said pile in a foreand-aft diection and means actuated at a point in the cycle of horizontal movement for causing said 'gripper to descend toward the pile, seize a sheet, and then move diagonally upwardly and rearwardly in a straight line path to raised position, whereby the sheet is withdrawn from beneath the hold-down before being forwarded from the pile. v

3. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a vertically movable pile board comprising, in combination, a hold-down member disposed ,at the forward edge of the pile and adapted to press `resiliently upon the successive top sheets thereof, a feeder head supported above the pile, a suction gripper movably carried by said feeder head, means for reciprocating said gripper horizontally above the rear portion of said pile in a fore-and-aft direction and means actuated at the rearmost point of the horizontal reciprocating path of movement of the. gripper for causing said gripper to descend toward the pile, seize a sheet, and then move diagonally upwardly again along a straight line path, whereby the 75.

"comprising,

sheet is withdrawn from beneath the hold-down before being forwarded from the pile.

4. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a vertically movable pile board comprising, in combination, a hold-down member disposed at the forward edge of the pile and adapted to press resiliently upon the successive top sheets thereof, a feeder head supported above the pilefa suction gripper movably carried by said feeder head, means for reciprocating said gripper horizontally above the rear portion of said pile in a fore-and-aft direction, means actuated at the rearmost point of thel path' of horizontal reciprocating movement of the gripper for causing said gripper to descend toward the pile, seize a sheet, and then move diagonally upwardly again along a straight line path, whereby the sheet is withdrawn from beneath the hold-down before being forwarded from the pile, and means included in said first named means for causing a momentary dwell in the reciprocating movement of the gripper at said rearmost point for permitting said sheet seizing and withdrawing movement to be completed before the forward feeding movement takes place.

5. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a pile board, comprising, in combination, a feeder head supported above the pile, a. diagonally extensible telescoping suction gripper movably carried by said feeder head, means for reciprocating said gripper in a straight line horizontally above the rear portion of said pile in a fore-and-aft direction, and means actuated at a point in the cycle of horizontal movement for causing said gripper to be extended toward the pile, seize a sheet, and tnen be retracted diagonally upwardly and rearwardly to raised position, whereby the sheet is Withdrawn from beneath the hold-down before being forwarded from the pile.

6. Sheet feeding mechanism for separating and feeding sheets from a pile supported by a vertically movable pile board comprising, in combination, a hold-down member disposed at the forward edge of the pile and adapted to press resiliently upon the successive top sheets thereof, a feeder head supported above the pile, a suction gripper movably carried by said feeder head, means for reciprocating said gripper horizontally above the rear portion of said pile in a fore-and-aft direction, means actuated at the rearmost point of the horizontal reciprocating path of movement of the gripper for causing said gripper to descend toward the pile, seize a sheet, and then move diagonally upwardly again along a straight line path, whereby the sheet is withdrawn from beneath the hold-down before being forwarded from the pile, and means for winding the rear edges of the sheets during the sheet separating and forwardly movementof said gripper, the rearwardly disposed gripper means and said winding means 'comprising the sole means for feeding the sheets oif the pile.

7. Sheet feeding mechanism for separating and feeding sheets from a pile supported on a pile board which is carried by a supporting frame in combination, a supplemental frame extending above the pile board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction of feed, a sheet gripper Amounted for longitudinal reciprocation on said trackway, mechanical driving means for reciprocating said gripper member along said trackway. and pneumatic means for moving said gripper downwardly toward the pile, effecting the seizure of a sheet thereby, and moving the gripper diagonally upwardly and rearwardly along a straight line path to its raised position. V

3. Sheet feeding mechanism for separating and feeding sheets from a; pile supported on a pile board which is carried by a supporting frame comprising, in combination, a supplemental frame extending above the pile board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction o feed, a sheet gripper mounted for longitudin-al reciprocation on said trackway, mechanical driving means for reciprocating said gripper member along said trackway, and pneumatic means operating at a point in the cycle of reciprocating movement for moving said gripper downwardly toward fthe pile, effecting the seizure of a sheet thereby, and moving the gripper diagonally upwardly and rearwardly along a straight line path to its raised position for resumption of said reciprocating movement by said mechanical means.

9. 'Sheet feeding mechanism for separating and feeding sheets from a pile supported on a pile board which is carried by a supporting frame comprising, in combination, a supplemental frame extending above the pile board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction of feed, a sheet gripper member mounted l for-longitudinal reciprocation on said trackway, mechanical driving means for reciprocating said gripper member along s ai'd trackway alternately in opposite directions, said gripper member comprislng a rearwardly inclined cylinder, a piston sli'dable therein, and a sheet gripper element on the lower end of said piston, means for controlling the supply of uid prsure to said cylinder to cause said piston to move to and from the pile of sheets to seize and withdraw a sheet from the pile, and means for timing the admission of fluid pressure with respect to the horizontal reciprocation of said member so as to insure that at least the sheet withdrawal movement has a rearward component.

10. ISheet feeding mechanism for separating and feeding sheets from a pile supported on a pile board which is carried by a supporting frame comprising, in combination, a supplemental frame extending above the pile board, a, horlzontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction of feed, a sheet gripper member mounted for longitudinal reciprocation on said trackway, mechanical driving means for reciprocating said gripper member along saidl trackway, said gripper member comprising a rearwardly inclined cylinder, a piston slidable therein, and a sheet gripper element on the lower end of said piston, means for controlling the supply of fluid pressure to said cylinder to cause rection of feed, a bracket associated with saidtrackway,y imeans for adjustably securing said bracket to said supporting frame at selected points longitudinally of the direction of feed so as .to position it above the rear portions of piles of sheets of varying lengths, a sheet gripper member sli'dably mounted on said trackway, means for reciprocating said gripper member along said trackway including a lever fulcrumed on ,said bracket and connected to said gripper member, and operating means for said lever, said lever being connectable to said operating means at a number of points along said supporting frame depending on the adjustment of said bracket.

12. Sheet feeding mechanism for separating and feeding sheets from a pile supported on a pile board which is carried by a supporting frame comprising, invcombinatioma supplemental frame extending above the pile board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of .the direction of feed, a bracket associated with said trackway, means for adjustably securing said bracket to said supporting frame at selected points longitudinally of the direction of feed so als to position it above the rear portions of piles of sheets of varying lengths, a sheet gripper member slldably mounted on said trackway, means for reciprocating said gripper member along said trackway including a bell crank fulcrumed on said bracket, a link connecting one arm of said bell crank to said gripper member, and operating means for said bell crank, said operating meam comprising a. horizontal bar and means for reciprocating it vertically in constant parallel relation to the top of the pile, and a sliding connection between the other arm of said bell crank and sai'd bar.

13. Sheet feeding mechanism for separating and feeding sheets from a pile supported on a pile board which is carried by a supporting frame comprising, ln combination, a supplemental frame extending above the pile board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction of feed, a bracket associated with said tramway, means for adjustably securing said bracket to said supporting frame at selected points longitudinally of the direction of feed so as to position it above the rear portions of piles and said bar, and a winding nozzle carried by said bracket and adjustable therewith, said noz` zle being directed toward the pile at its rear upper edge.

14.'Sheet feeding mechanism for separating 'and .feeding sheets from a pile supported on a pile board which is carried by a supporting frame comprising, in combination, a supplemental frame extending above the pile'board, a horizontal trackway carried by said supplemental frame and disposed above the pile longitudinally of the direction of feed, a bracket associated with said trackway, means for adjustably securing said bracket to said trackway at any point therealong longitudinally of the direction of feed so as to .position it above the rear portions of piles of sheets of varying lengths, a sheet gripper member slidably mounted on said trackway, means for reciprocating said gripper member along said trackway including a bell crank fulcrumed on said bracket, a link connecting one arm of said bell crank to said gripper member, and operating means for said bell crank, said operating means comprising a horizontal bar and means for reciprocating it vertically in constant parallel relation to the top of the pile, and a sliding connection'between the other arm of said bell crank and said bar.

15. In a sheet feeding device of the class described, in combination, a supporting frame disposed above a pile of sheets, an extensible sheet gripper member, means for moving said member along said frame alternately forwardly and rearwardly, said member comprising a cylinder whose axis is inclined rearwardly and upwardly, a pistonadapted to reciprocate in said cylinder along said axis, a vertically disposed suction cup on the lower end of said piston, and means for regularly placing said cylinder into and out of communication with a source of vacuum, whereby said piston and cup will move toward and from the pile to seize and lift a sheet, along Aa rearwardly and upwardly inclined path.

16. In a sheet feeding device of the class described, in combination, a supporting frame disposed above a pile of sheets, a longitudinally disposed horizontal track bar carried by said frame and being of a length at least equal to the length o f the longest sheet intended to be handled by the device, a substantially U-shaped .bracket lying in a horizontal plane, means for adjustably securing the arms of said bracket at selected points along said track bar, a sheet gripper member slidably engaged with said track bar and confined between the arms of said bracket for limited oscillatory movement along such portion of said track bar as determined by the selective positioning of said bracket.

17. In a sheet feeding device of the class described, in combination, a supporting frame disposed above a pile of sheets, a longitudinally disposed horizontal track bar carried by said frame and being of a length at least equal to the length of the longest sheet intended to be handled by the device, a substantially U-shaped bracket 1ying in a horizontal plane, means for adjustablyy securing the arms of said bracket at selected points along said track bar, a sheet gripper member slidably engaged with said track bar and conned between the arms of said bracket for limited oscillatory movement along such portion of said track bar as determined by the selective positioning of said bracket, and means for oscillating said gripper member, said means including parts carried by said adjustable bracket and connected to said gripper member, parts carried by said frame, I

and means for maintaining operative driving connections between said parts at any position of said bracket and gripper member.

18. In a sheet feeding device of Athe class described, in combination, a supporting frame disposed above a pile of sheets, a longitudinally disposed horizontal track bar carried by said frame and being of a length atleast equal to the length ing in a horizontal plane, means for adjustably securing the arms of said bracket at selected points along said track bar, a sheet gripper member slidably engaged with said track bar and confined between the arms of said bracket for limited oscillatory movement along such portion of said track bar as determined by the selective positioning of said bracket, and means for oscillating said gripper member, said means including a bell crank fulcrumed on said bracket and having one of its arms connected to said gripper member, an oscillating bar carried by said frame and maintained in parallel relation with said track bar, and an adjustable sliding connection between said oscillating bar and the other arm of said bell crank.

19. In a sheet feeding device of the class described, a telescoping suction gripping member comprising a block having a cylindrical chamber therein which is inclined'at an angle to the horizontal, a` piston adapted to reciprocate in said cylindrical chamber, a hollow piston rod coaxial with said cylindrical chamber, a suction cup on the end of said rod having a vertical axis and adapted to maintain its vertical position during all movements of said piston.

20. In a sheet feeding device of .the class described, in combination, a horizontally oscillating gripper member, a pile jogger blade disposed rearwardly of the pile of sheets and guided upon a horizontal longitudinally extending supporting element, spring means for urging said blade forwardly toward said pile, and an abutment on said slidable jogger adapted to be contacted by a cooperating abutment on said gripper member for moving said jogger away from the pile during the removal of a sheet by said gripper member.

21. The method of separating and feeding sheets from a pile to a machine for further handling or treatment, comprising gripping the uppermost sheet at a point adjacent its rear edge, drawing the rear portion of the sheet diagonally rearwardly and upwardly along a straight line path, then moving said gripped portion of the sheet forwardly along a horizontal path and then releasing the sheet.

22. 'I'he method of separating Aand feeding sheets from a pile to a machine for furl-her handling or'treatment, comprising floating the top sheets of the pile from the rear thereof, gripping the uppermost sheet at a point adjacent its rear edge, drawing the rear portion of the sheet diagonally rearwardly and upwardly along a straight line path, then moving said gripped portion of the sheet forwardly along a horizontal path, then releasing the sheet from the gripping means, and conveying it off to the machine to be fed.

23. The method of separating and feeding sheets from a pile to a machine for further handling or treatment, comprising holding down the front edges of the sheets of the pile, floating the top sheets of the pile from the rear thereof, gripping the uppermost sheet at a point adjacent its rear edge, drawing the rear portion of the sheet diagonally rearwardly and upwardly along a straight line path, thus withdrawing the front edge 0f the sheet from beneath 'the hold-down means, then moving said gripped portion of the sheet forwardly along a horizontal path over the hold-down means, then releasing the sheet from member toward the pile of sheets along a downwardly and forwardly inclined path and for retracting said lgripper member along the same path in a reverse direction upon seizing a'sheet, winding means for floating the top sheets of the pile. and means for limiting the` elevation of the top sheet under the iniiuence of said winding means, said means being yieldable upwardly upon elevation of the sheet by said gripper member.

ANTON STOBB.