US2243170A - Sheet feeder - Google Patents

Description

May 27, 1941. F. w. SEY'BOLD ETAL 2,243,170

SHEET FEEDER 2 Sheets-Sheet 2 Filed March 16, 1939 Patented May 27, 1941 A ariane snaar Fenner.

Frederick W.

seybols and Davia r. Sanford,

Elizabeth, N. J., assignors to American Type ed, Elizabeth, N. J., a corporation of New Jersey Founders, Inccrporat Application March 16,

116 Claims.

This invention relates to sheet feeding apparatus and more particularly to devices for separating the sheets from -a pile and forwarding them to the printing press, folder or other machine to which they are to be fed.

The general object of the invention is to provide a novel sheet feeder which embodies an improved device for winding the sheets during the separating and feeding operations.

In its broader aspects, the invention is applicable to sheet feeding devices of widely varying types, but for purposes of illustration, the preferred embodiment is shown and described herein as incorporated in a sheet feeder of the kind which forms the subject of the copending application of David P. Sanford, Serial No. 232,443, filed September 29, 1938.

The sheet feeder described in that application is one which is readily adjustable to feed sheets singly and in spaced relation, or to effect what is known as stream feeding, that is, `forwarding the sheets in a continuous line with each sheet overlapping the adjacent edge of the neXt succeeding one. This feeder is provided with a hold-down member ward portion of the pile, and a suction gripper which operates above the pile to withdraw the successive top sheets from beneath the holddown member and move them forwardly to the conveyor which carries them to the printing pres-s, folding machine, cutter, or other instrumentality in conjunction with which the feeder is employed.

As in most devices of this kind, the level of the top of the pile is maintained by means of automatically operated pile elevating mechanism; the mechanism in this particular instance being actuated by the hold-down member'which presses upon the pile -near the front edge thereof.

Also, in the illustrative example, the sheet lifting or separating function is performed by the same gripper member which moves the sheet forwardly to the conveyor, although the novel winding device is not limited to use with this 4class of feeder.

The separation of the uppermost sheet -of the pile from the underlying sheets is greatly facilitated by the winding operation which comprises directing a blast of air against the rear edges of a number of the uppermost sheets, in order to separate or fluff up these -sheets and to lift the top sheet toward the suction gripper so that it may be readily engaged by the gripper as it descends. Preferably, the -action of the air blast is not interfered with or affected in any way by disposed adjacent the for- 1939, Serial No. 262,256

the provision of hold-down or pressure devices acting on the rear portion of the pile, so that the rear margins of the uppermost sheets are entirely free to rise under the influence of the blast.

The elimination yof `such pile engaging or pressure members acting upon the rear edge of the pile makes it unnecessary to accurately set the height control gauge, the sheets being blown upwardly to such an extent that the suction gripper may become active and effective in every instance, despite minor variations in the distance between the bottom of the suction gripper and the top -of the solid pile, when the suction gripper is in its lowest position. This is an important advantage of the mechanism, especially wher-e the pile of sheets being acted upon is irregular, having a somewhat uneven upper surface, as for instance where the pile comprises a large number of sheets certain portions only of which have been previously printed. The air blast further functions to float each sheet, after its separation from the pile, forwardly to the conveyor, the suction gripper having engagement with the rear edge of the sheet during a portion of its travel,

- and thus controlling its rate of movement, but

the blast being active to facilitate the actual introduction of the leading edge of the sheet into the conveyor, maintaining this leading edge at such elevation that it passes freely over the holding-down member at the front of the sheet.

In prior constructionsof this type, the blast nozzles or mouthpieces have been disposed in a xed relationship with the feeder supporting structure, or at best, have been adjustable to direct the separating air blast at a predetermined elevation with respect to the feeding level of the pile of sheets, this level being regulated by the pile height gauge means elevator.

It frequently occurs, however, that the stack being fed is curled or wavy due to the presence of moisture or to other causes, so that the elevation of the pile at the rear end thereof is not the same as that at thev forward edge or at other points where the pile height gauge finger may be applied. Furthermore, the relative heights of the front and rear portions of the pile may not remain constant even during a given run of sheets, due to the weight of the pile.

which actuates the pile Because of these abnormal and sometimes varying conditions, the operati-on of feeders equipped with fixed winding devices has been subject to frequent stoppages. vation of the pile at the height gauge and adjacent the blast mouthpiece changes during the If the relative elerun so that the sheets are below the effective blast, then the device may fail to feed a sheet; and, on the other hand, if the reverse is true and too many of the uppermost sheets of the pile are labove the blast level, then the feeder is likely to feed doubles The present invention obviates these difculties by providing a moving blast device, the operation of which is synchronized with the feeding cycle.

In its preferred embodiment, the invention contemplates the provision of a vertically reciprocating blast tube guided in a portion of the station-ary supporting frame for the suction feeder. The lower end of the tube is provided with 1an orice through which the air is directed toward the pile at a predetermined level and the tube is adapted to be intermittently depressed preferably, although not necessarily, by the descending movement of the suction gripper. By suitable modifications within the scope of the invention, the movement of the blast Ynozzle may be synchronized in any phase with the movement of the tube adapted to be contacted and Idepressed agains-t the resilient pressure of the spring by an operating element of the gripper.

As the suction element descends, the blast nozzle also moves downwardly and uffs up the sheets so that the uppermost sheet is brought up to meet the suction element. When the latter element is at its lowermost point and in position for taking a sheet, the blast mouthpiece is also at its lowermost position insuring an effective blast at a relatively low leve. As the suction gripper rises, the mouthpiece when the sheet is fully separated at its rear edge and is about to be moved forwardly to the conveyor, the blast is delivered at about the same level as the front of the pile. At this level, the top sheet is effectively separated from the one the present invention, the views depicting successive positions of the feeding and winding elements;

Figure 5 is a fragmentary top plan view of the rear central portion of the sheet feeding mechanism shown in Figures 1 to 4;

Figure 6 is a View in rear elevation `of a portion of the mechanism, a part being broken away to r illustrate the blast or winding means; and a horizontal sectional view taken on line 'i-'i of Figure 6.

The general type of sheet feeder to which this invention may be applied is fully illustrated in the copending application to which reference has been made, and only so much of anism and supporting structure is also lifted, so that f will be described herein as is necessary to a proper understanding of the present invention.

All of the feeding and separating mechanism is mounted upon a main supporting frame or base which ispreferablyprovided with upwardlyproazeaivo jecting side frame portions for the convenient mounting of certain transverse supporting rods, cross braces, and rotary shafting.

A vertically adjustable pile board is provided for supporting the pile of sheets S which are to be fed to the printing press, folding machine, or similar device. The pile board is gradually elevated as the pile of sheets becomes depleted, and this gradual raising cf the support may be accomplished by any suitable mechanism, such as in the application referred to;

control device arranged in contact with the pile of sheets, as will be moreffully described hereinafter.

At the forward end of the pile S there may be disposed certain sheet forwarding devices which are adapted toy carry the sheets, either succesthe tapes H which are trained about this roller, and a corresponding roller at the opposite or delivery end of the conveyor (not shown). The roller l!) is mounted upon a shaft l2 which is driven in adjustable synchronism with the feeding and separating devices for the sheets. A cooperating presser roll I4 is disposed above the roller l0, and the sheets are fed `between the tape roller and the presser roll from the top of the pile S.

In order to hold down the sheets adjacent one as fully described in the aforesaid copending application.

A sheet separating and forwarding device, represented generally rby the reference character F, and which includes the suction gripper 20, vided 1n order to separate the top sheet of the down member I5, and then move the sheet forwardly in sliding relation to the upper surface of conveyor. The sheet gripping mechanism F and the conveyor C, as previously indicated, are driven in synchronism with the machine to which the sheets are being fed, and the conveyor C preferably may be driven at one or the other of a plurality of predetermined speeds, depending .upon whether serial feeding with various degrees of spacing, or stream feeding with various degrees of overlap, is desired.

'I'he mechanism for effecting the removal of the uppermost sheet from the pile and for forwarding it to the conveyor will now be described.

extending supporting seam fragmentarily at in Figure 5 of the drawings. Suitably secured to the lc'wver edge `of Vthis member 2K5, as by means of the .b olt's" or screwsV 21,"is the rearwardly projecting Vsupporting bar. 28.

Adjacent the rear end of this supporting bar there is secured the block M. The lconnection between the block M and thev bar 2.84 is` preferably made adjustable so that the block may be moved to and retained in any 'desired position longitudinally of the feeder to adapt it to, sheets of different lengths'. "lo" attain this adjustment he block M maybe provided withV a grooveor recess shaped to receive the bar'and provided with overhanging plates or gibs, such as those indicated at 23, secured to the block by means of the screws 30. The block may be held in its adjusted position by means of a thumb screw or any other suitable clamping means.v

A pivot shaft 33 passes through a narrowed upper portion 34 of the against rotation with respect to the block as byV means of the set screw 3,5. Embracing this portion 34 and pivotally mounted upon the -ends of the shaft 33 is the bifurcated end of the lever or rocker member Y3.5. u provided with a foot 38 whi h is adapted to abut a ledge 3S on the block M during certain portions of the cycle of operation of the feeding gripper. The otherl bifurcation 4,0 of the lever is urged downwardly as by means of the spring 4 l, the lower end of which is secured to a portion of the block M. By this means, the forward end of the rocker lever 3S is continually urged in an upward direction. This forwardend ofthe lever is provided with a transverse Opening through which extends a shaft or axle 42 andA which is secured against rotation therein by means of thel set screw 43.

There is connected to the rocker 3E, by means of the shaft 42, a swinging carrier 445 whichis substantially oi an inverted L-shape, the angle portion of which is bifurcatedV and pivotally mounted upon the ends of the shaft or axle 42. The longer, normally vertically extending arm 45 of the carrier member 45 is pivotally connected with the suction gripper members 20 as at 41, this pivotal connection being provided with means for transmitting the vacuum from a suitable source of suction to the flexible cup 48 carried by the gripper member 20. There are preferably two of the gripper elements 20; one or both of them is formed with a projection 49 which is adapted to contact and bear against the stop pin 58 which is carried'bv a projection on the lower end of the supporting member'41; and these abutments 49 and 50 are urged into contact with each other by means of the coil spring 5,2, one end of which is connected with a projection 53 on Vthe gripper member 2l) and the other end of which -is secured as at 54 to a point on the long arm of the supporting carrier 45. The upper forwardly projecting arm 5.1 of the member 45 is connected by means of a pivot pin 58 with a block 59 which is slidably mounted upon a horizontally disposed bar fill, which, when the mechanism is operated, has a controlled rising and falling movement and comprises the means for transmitting driving force froml the driving mechanism to the gripper element vactuating device. The bar 6l) remains horizontal and parallel to the supporting bar 28 throughout its movement, this arrangement permitting the adjustment of the block M and its associated mechanism longitudinally onv the support 2 8` block M and is secured 'One of the bifurcations 31 is while maintaining .at all times its driving con nection with thismechanism.

' Thispa'rallelmotion of the bar 6i) is attained by means of the following mechanism. Two par- Y allel pins S2 and 6`3 project from the supporting bracket 25 and carry upon their respective outer ends two bar operating levers, a three-armed lever mounted upon the pin 62, and a threearmed lever 66 mounted'upon the pin E3. Parallel downwardly extending arms 61 and 68 of these levers are connected by means of a link 'Hi so that the levers are constrained to partake of simultaneous rocking movements through equal angles. One arm 1I of the lever 65 is pivotally connected to the actuating rod BD as by means of the Apin 12, and an arm 13 of the lever 65, of the same length and inclined at the same angle as the arm 1|, is pivotally connected to the bar '59 as at 14. Thus, it is clear that rocking movements'of these levers must be equal and simultaneous and will bring about very equal rising and falling movements of the actuating bar to. A spring 15 acting uponan upwardly extending arm 15 ot the lever 65 and connected to a stationary part of the device tends to rock both levers in a clockwise direction, as viewed in Figure l, and causes a cam follower 18 rotatably mounted upon the upwardly extending arm 'E9 of the lever 65 to bear at all times against a cam 8o, fixed upon a cam shaft 8! which is driven in proper synchronism with the conveyor C and the device to which the sheets are fed.

The bar St, as it descends beyond a certain point, is adapted to contact with the ro1ler55 secured to the swinging gripper carrier 45 and cause it to move downwardly against the influence of the spring 4I so that the gripper 2l may seize the top sheet of the pile.

The various movements of the separating and feeding mechanism? during its cycle oi operation will now be briefly described; reference being made to the aforesaid copending application for a more detailed disclosure of the construction and operation of this device. Figures l, 2, 3, and 4 of the drawings show successive Ystages in the cycle of operation. In Figure 1 the bar Gli has, through its contact with the roller 55, caused the swinging carrier 45 to descend so that the suction gripper 20 is in contact with the tcp sheet t of the pile S adjacent its rear margin. At this point, suction is applied to the gripper device causing the sheet t to adhere thereto.

In Figure 2 of the drawings the actuating bar Si! has moved upwardly a shortA distance and has permitted the carrier 4,5 to rise vertically under the influence oi' the spring 4l, thus causing the suction gripper Roto lift thesheet t a slight distance from the next underlying sheet of the pile. At this point a roller S5 carried by the projection 53 of the member 2U contacts with the underneath cam surface of the cam bar 81 which projects forwardly from the block M.

Further upward movement of the bar .66, as indicated in Figure 3 of the drawings, permits the carrier 45 to move still further in an upward direction until the foot 38.01 the rockerlever 35 comes to rest against the ledge 39 of the block M. During this stage of the movement of the feeding elements the roller 3.5, being in Contact with the cam surface 85, causes the suction gripper 2.8 to tilt rearwardly so that the abutment 49 leaves the pin 5B and tensions the spring 41 which normally maintains the suction gripper -K and the carrier 45 in xed relation. This rearward tilting movement of the gripper causes the sheet t to move rearwardly and withdraws its forward edge from beneath the hold-down member I 5, at the same time moving the thin iiexible rear pile guide 98 momentarily rearwardly.

Further upward movement of the bar 60 causes the carrier to swing forwardly about the pivot shaft 42 since the rocker 36 can rise Ano further due to the impingement of the foot 38 against the ledge 39. This forward movement ofY the carrier 45 causes the cam roller 85 of the gripper 29 to move along the curved cam surface 88 of the bar 37, and to cause the member 20 to maintain the proper angle with respect to the carrier 45 to effect the forward feeding movement of the sheet t into the conveyor C, as clearly shown in Figure 4 of the drawings. Upon the return movement of the actuating bar 60 in a downward direction under the iniiuence of the cam 80, the members 45 and 36 are again rocked downwardly through substantially the same orbits until they again resume the positions shown in Figure 1 for seizing the next sheet of the pile. It will be understood of course that in the case of stream feeding the action of the feeding device F in separating and forwarding the sheets is more rapid than the carrying 01T of the sheets by the conveyor C, and thus successive sheets are inserted within the bite of the conveyor beneath the next preceding ones, in overlapping relation.

During the entire cycle of operation of the separating and feeding mechanism F, a continuous blast of air is directed toward the upper portion of the rear face of the pile S. For supplying this blast of air against the sheets, the

following mechanism is provided. As very clearly shown in Figure 6 of the drawings, the block M in its rearward portion is provided with a vertical `bore 90 within which there is disposed for vertical reciprocation the blast tube S2. The lower portion of this tube 92 is provided with the forwardly directed slot or outlet orifices 95 and the lower end of the tube is closed by means of the plate 95 which forms a forwardly extending deiiector member, and is bent upwardly and inwardly at the rear of the tube 92 to provide a guiding and spring seating bracket portion 98. A guide pin H20 is threaded into the lower face of the block M and locked rigidly thereto by means of the nut I 9|. This pin passes through an opening in the upper portion |92 of the bracket 98 and also through an enlarged opening in the lower rearwardly extending portion |03 of the bracket. The head |95 of the pin provides suitable stop means for limiting the downward movement of the bracket and thus of the blast tube 92. A coil spring |06 surrounds the pin |99, passes through an opening in the plate 96, and is seated between the lower face of the upper portion |92 of the bracket 98 and the head |65 of the pin, thus tending to urge the bracket upwardly until the portion |02 abuts the nut I0 I The upper end of the tube is closed as at II and is adapted to be contacted with and depressed by the bar 99 during the final stages of the downward movement thereof. An air supply nipple II2 is seated within the bore II3 provided laterally in the block M, and the blast tube 92 is placed in communication with the tube I I2 by means of the elongated slot I l5 in its side wall. The slot II 5 is of sufficient length so that it is at al1 times'in communication with the tube II2 during the vertical reciprocating movement of the tube 92 in the block.

The operation of the improved blast mechanism in conjunction with the feeder device F will now be described. As the actuating bar 60 descends, the tube 92 is also moved downwardly until both of these elements have reached their lower limit as shown in Figure 1. At this point, the suction gripper 20 is seizing a sheet upon the top of the pile S, and the outlet slot or orifice 95 of the blast tube 92 is at a relatively low point as referred to the top of the pile S. As the suction gripper moves upwardly, the tube 92 is also moved upwardly under the influence of the spring |06. An intermediate position of the'blast tube is shown in Figure 2 of the drawings, where the suction gripper 20 has raised the top sheet t preparatory to moving it rearwardly from beneath the hold-down member I5. Furtherupward movement of the bar 69, as shown in Figure 3 of the drawings, permits the blast tube to move to its upper limit of movement as determined by the contact of the bracket 98 with the nut IIlI, and at this point, the blast orifice 95 is at substantially the same level as the front edge of the pile as affected by the hold-down member I5. The blast tube remains at this level during the forward feeding of the sheet, and thus a considerable portion of the blast of air is effective in passing under the top sheet t and iioating it above the pile and thus aiding materially in the feeding of the sheet into the conveyor C. At the same time, the elevation of the blast is sufcient to prevent the feeding of doubles It will thus be seen that there has been provided by the present invention a novel and effective blast or winding means which cooperates with the sheet feeding mechanism in separating the sheets and also in feeding them forwardly from the pile. The depression of the blast device insures that the uppermost sheets of the pile will be iiuifed and separated during the initial seizure of the top sheet by means of the gripper member, and also the upward movement of the blast insures that suiiicient of the air is passed beneath the single top sheet being removed, and that no more than one sheet is iioated toward the conveyor.

It will be understood that various changes and the embodiments illustrated and described herein without departing from the scope of the invention as defined by the following claims..

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

1. In a sheet feeder for separating and forwarding sheets from a pile, in combination, the sole hold-down means for said sheets being at the forward edge of the pile, the rear portions of the pile being free from vertical pressure, means for separating the top sheet from the underlying sheets, withdrawing it from said hold-down means, and forwarding the sheet toward the device to which the sheetsare being fed, vertically movable means for delivering a continuous blast of air against the upper rear edge portion of the pile, and means for moving said last named means in synchronism with the separating and forwarding means.

2. In a sheet feeder for separating and forwarding sheets from a pile, in combination, means for holding down the forward edge of the pile, means for separating the top sheet from the underlying sheets, withdrawing it'from beneath said hold-down means, and forwarding the sheet toward the device to which the sheets are being fed, and means for delivering a vertically moving substantially horizontally directed blast of air against the rear side of the pile in order to facilitate the separation and forwarding operations.

3. In a sheet feeder for separating and forwarding sheets from a pile, in combination, means for separating and forwarding the top sheet of the pile, and separately mounted means for delivering a vertically moving substantially horizontally directed blast of air against the rear side of the pile in order to facilitate the separation and forwarding operations.

4. In a sheet feeder for separating and forwarding sheets from a pile, in combination, a member movable upwardly and downwardly above said pile for separating and lifting the top sheet from the pile, an independently mounted blast nozzle spaced rearwardly from the rear edge of the pile and movable vertically during the operation of the feeder to deliver a continuous blast of air against portions of the upper rear side of the pile to aid in the separation of the sheets, and means for causing said nozzle to move downwardly behind the pile when themembermoves downwardly to seize a sheet, and for causing the nozzle to move upwardly as the member moves upwardly to separate the sheet from the pile.

5. In a sheet feeder for separating and forwarding sheets from a pile, in combination, a hold-down device pressing downwardly upon said pile at a point spaced from the rear edge of the pile, a member for separating and lifting the top sheet from the pile, a blast nozzle spaced rearwardly from the rear edge of the pile and movable vertically during the operation of the feeder to deliver a continuous blast of air against portions of the upper rear side of the pile to aid in the separation of the sheets, and means for causing said nozzle to move downwardly behind the pile to a point below the level of the hold-down device when the member moves downwardly to seize a sheet, and for causing the nozzle to move upwardly to the approximate level of the hold-down device as the member moves upwardly to separate the sheet from the pile.

6. In a sheet feeder for separating and forwarding sheets from a pile, in combination, a hold-down device pressing downwardly upon said pile at the front edge thereof, a suction gripper operable above said pile to separate the top sheet from the underlying ones and forward it toward the device to which the sheets are to be fed, means for causing said gripper to descend toward said pile, seize the top sheet, then move upwardly and rearwardly to withdraw said sheet from beneath said hold-down device, and then forwardly to deliver the sheet for subsequent handling, a blast nozzle spaced rearwardly from the rear edge of the pile and movable vertically during the operation of the feeder to deliver a continuous blast of air against a portion of the upper rear side of .the pile, means for causing the nozzle to move downwardly behind the pile to a point below the level of the hold-down device when said gripper moves downwardly to seize a sheet, and means for causing the nozzle to move upwardly during the separating and retracting movements of the gripper until it reaches a level approximating that of the holddown device and to remain at that level during the forward sheet delivering movement of the grippers, whereby lthe blast facilitates the separation of the successive top sheets and serves to float them above the pile during the forwarding movement.

7. In a sheet feeder for separating and forwarding sheets from a pile, in combination, a hold-down device pressing downwardly upon said pile at the front edge thereof, an automatically actuated pile elevator for maintaining the top -of the pile at an approximately constant level, a suction gripper operable above said pile to separate the top sheet from the underlying ones and forward it toward the device to which the sheets are to be fed, means for causing said gripper to descend toward said pile, seize the top sheet, then move upwardly and rearwardly to withdraw said sheet from beneath said holddown device, and then forwardly to deliver the sheet for subsequent handling, a blast nozzle spaced rearwardly from the rear edge of the pile and movable vertically during the operation of the feeder to deliver a continuous blast of air against a portion of the upper rear side of the pile, means including a portion of the gripper operating means for causing the nozzle to move downwardly behind the pile to a point below the level of the hold-down device when said gripper moves downwardly to seize a sheet, and means for causing the nozzle to move upwardly during the separating and retracting movements of the gripper until it reaches a level approximating that of the hold-down device and to remain at that level during thev forward sheet delivering movement of the grippers, whereby the blast facilitates the separation of the successive top sheets and serves to iioat them above the pile yduring the forwarding movement.

8. In a sheet feeder for separating and for- !warding sheets from a pile, in combination, the sole hold-down means for said sheets being at the forward edge of the pile, the rear portions of the pile being free from Vertical clamping pressure, a suction gripper operable above the rear portion of said pile to separate the top sheet from the underlying ones and forward it toward the device to which the sheets are to be fed, means for causing said gripper to descend toward said pile, seize the' tcp sheet, then move upwardly and rearwardly to withdraw said sheet from beneath said hold-down device, and then forwardly to deliver the Sheet for subsequent handling, a blast nozzle spaced rearwardly from the rear edge of the ple and movable vertically during the oper-ation of the feeder'to deliverV a continuous blast of air against a portion of the upper rear side of the pile, means for causingy the nozzle to move downwardly behind the pile to a point below the level of the hold-down device when said gripper moves downwardly to seize a sheet, and means for causing the nozzle to move upwardly during the separating and retracting movements of the gripper until it reaches a level approximating that of the holddown device and lto remain at that level during the forward sheet delivering movement of the grippers, vwhereby the blast facilitates the separation of the successive top sheets and serves to float them above the pile during the forwarding movement.

9. In a sheet feeder of the class described, in combination, a main frame, carrying a pile of sheets to be fed, a bracket carried by said main frame so as to overhang the rear edge of said pile, a gripper member movably supported from said bracket, actuating means for said gripper member operatively connected thereto, an air 'blast tube carried by said bracket vertically 10. In -a sheet feeder of the class described, in

combination, a main frame, carrying a pile of sheets to be fed, a bracket carried by said main frame so as to overhang the rear edge of said pile, a gripper member movably supported from said bracket, actuating means for said gripper l r member operatively connected thereto and comprising an element projecting into close proximity to said bracket, an air blast tube carried by said bracket vertically reciprocable with respect thereto and adapted to extend behind the upper part of the rear side of the pile, a nozzle opening in the tube directed toward the pile, the upper portion of said tube projecting from said bracket in a position to be contacted and moved vertically by said element, and spring retracting means for said tube adapted to resiliently resist the movement of said tube under the iniiuence of said element.

11. In a sheet feeder of the class described, in combination, a main frame, carrying a pile of sheets to be fed, a bracket adjustably carried by said main frame so as to overhang the rear edge of said pile, a suction gripper member movably supported from said bracket, actuating means for said gripper member operatively connected thereto and comprising an element projecting into close proximity to said bracket, an air blast tube carried by said bracket vertically reciprocable with respect thereto and adapted to extend behind the upper part of the rear side of the pile, a nozzle opening in the tube directed toward the pile, the upper portion of said tube projecting from said bracket in a position to be contacted and moved vertically by said element, and spring retracting means for said tube adapted .toV yield under the influence of said element.

12. In a sheet feeder ofthe class described, in combination, a main frame, carrying a pile of sheets to be fed, a bracket carried by said main frame so as to overhang the rear edge -of said pile, a gripper member movably supported from said bracket, actuating means for said gripper member operatively connected thereto, said actuating means adapted to cause said gripper member to descend upon the pile, seize the. top sheet, move it upwardly and rearwardly to separate it from the underlying sheets and then forwardly toward the machine to which they are. being fed, an air blast tube carried by said bracket vertically reciprocable with respect thereto, and adapted to extend behind the upper part of the rear side of the pile, a nozzle opening in the tube directed toward the pile, a portion of said tube projecting from said bracketin a position to be contacted and moved downwardly by said element when, the gripper member descends to seize a sheet, until the nozzle opening is well below the top of the pile, and spring retracting means for said tube for resiliently urging it upwardly to the point where the opening is at the approximate level of the top of the pile when the gripper member is moving the sheetforwardly, whereby the blast aids in separating the top sheet and floats it during the forward' feeding movement.

a position to be contacted 13. In a sheet feeder of the class described, in combination, a main` frame, carrying a pile of sheets to be fed, a sub-frame carried by said main frame and disposed above the pile for supporting certain of the feeding elements, ablock carried by said sub-frame so as to overhang the rear edge of the. pile, said block being provided with a vertical bore, an air blast tube slidably disposed within said bore, an-outlet orice in said tube adjacent the lower end thereof, an air passageway in said block communicating with said bore, and an elongated inlet opening in the Wall of said tube adapted to communicate with said passageway at all times, resilient means for urging said tube upwardly toward the point where the outlet orice is at the approximate level of the top of the pile, the upper end of the tube projecting above the adjacent portions of said block and adapted to be contacted by and depressed by a moving part of the feeding elements.

14. In a winding device for sheet feeders of the class described, in combination, a block supported above and rearwardly of a pile of sheets to be fed, said `block being provided with a vertical bore, an air blast tube slidably disposed within said bore, an air passageway in said block connected with a source of compressed air, an inlet orifice in said tube communicatingwith said passageway, a laterally directed outlet oriiice in thek lower part of said tube, a bracket secured to end of said tube and adapted to proment of the tube, a guide pin projecting downwardly from said block and passing through an opening in said bracket, a coil compression spring on said pin and adapted to be seated between the head of the pin and said-bracket to urge the tube upwardly with respect to said block.

15. In a sheet feeder of the class described, in combination, a main frame, carrying a pile of sheets to be fed, a bracket carried by said main frame so as tooverhang the rear edge of said pile, a gripper member movably supported from said bracket, actuating means 'forsaid gripper member operativelyconnected thereto and comprisling a parallel motion including a horizontal bar adapted for substantially translatory movement in a vertical plane during the operation of said gripper member, said bar adapted to approach a-nupper surface of said bracket as it descends to cause Vthegripper member to lower ontov the pile, an air blast tube vertically reciprocable in said block and adapted tov direct a blast of air warding sheets from a pile, in combination, a

tally directed blast ofair against portions of the upper rearside of thev pile to aid in the separation of the sheets, and' means to actuate said nozzle in timed relationship with the cycles or movement of said member.

FREDERICK W. SEYBOLD. DAVID P. SANFORD.

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