US2593181A - Sheet feeder - Google Patents

Description

4 Sheets-Sheet l e u mlm JNVENTOR. BYHOWARD PR/TCHARD H. A. PRITCHARD SHEET FEEDER llnlllnl April 15, 1952 Filed July 3o. 194e mm mm vm mm ATTORNEUS April 15, 1952 H. A. PRITCHARD 2,593,181

SHEET FEEDER Filed July 50, 1946 4 SheetS-Shet 2 JNVENTOR.

OWARD A PRITCHARD B Maf/MMM,

ATTORNEJS April 15, 1952 H. A. PRrrcHARD 2,593,181

SHEET FEEDER Filed July 50, 1946 4v Sheets-Sheet 5 IN V EN TOR.

BYHowA RD A. PRITCHARD M7, pu afm ATTORNEYS April 15, 1952 H. A. PRrrcHARD 2,593,181

SHEET FEEDER Filed July 30, 1946 JNVENTOR.

E615 BYHowARD A. PR/TCHARD f@ wam/9% ww@ ATTORNEJS Patented Apr. 15, 1952 SHEET FEEDER Howard A. Pritchard, Hiram, Ohio, assignor to Harris-Seybold Company, Cleveland, Ohio, a corporation of Delaware Application July 30, 1946, Serial No. 687,074

23 Claims. 1

This invention relates to improvements inv sheet handling apparatus, and has to do especially with a feeder for stream feeding sheets from the forward end of a pile or other supply of sheets.

Stream feeding as conventionally practiced in the feeding of sheets to modern high speed presses involves separating the rear end of the top sheet from the supply, gripping the top sheet, blowing air forwardly beneath the separated and gripped sheet to float the sheet, and moving the sheet gripping means forward, thus permitting the moving blanket of air beneath it to advance the sheet into the grip of pull-out rolls or the like, whereupon the next sheet of the supply is taken and fed forward by the same procedure underneath the previous sheet.

While mechanism of this character has proven quite effective in practice, it has certain limitations and gives rise to certain difficulties when operated at very high speeds, or on especially large sheets, or on sheets which are in poor c-ondition for handling. For example, the forwardly directed blast of air must travel the length of the sheet and fully separate and float it before the sheet can be permitted to start forward and the time required for this operation limits the portion of each cycle available for other operations and therefore limits the speed of the feeding. This limitation of course becomes more serious as the length of the sheet increases, and as the weight of the sheet or the amount of ink previously printed thereon increases. Other factors such as waviness of the surface of the supply and the presence of adjacent printed and unprinted areas on the sheets interfere with the efficient functioning of the air blast.

As a result of these and other factors, difficulty is experienced in attempting to feed sheets rapidly oif the supply to the pull-out rolls or conveyor singly and in accurately straight and accurately timed condition. Since the accuracy of placement and timing of the sheets on the conveyor directly affects the efficiency of the registering devices to which the sheets are carried by the conveyor, the efficiency of feeding from the supply directly affects the productivity of the printing press.

Attempts have been made to construct stream feeding mechanism operable at the front edges of the sheets but such devices have been cumbersome and complicated and not adapted to high speed operation, and in some cases have involved momentary loss of sheet control during their cycle of operation.

In accordance with the present invention, a rotary feeding mechanism adapted to accomplish lapped feeding of sheets is contained in a compact carrier at the forward end of the supply, which mechanism is driven by simple driving connections and involves a minimum of reciprocating parts. Sheet gripping units, preferably embodying one or more suckers, is operated to roll up the front edge of the top sheet, thereby separating it from the sheet next below and permitting air to enter between it and the next sheet, the air being caused to enter by atmospheric pressure or by being blown under greater pressure from a nozzle, not shown, provided for the purpose. When the sheet has been lifted off the supply to a predetermined height and preferably without disturbing its rear edge, a second sheet gripping unit in the same carrier takes the sheet from the first gripping unit and raises it to an extent suicient to permit it to move forward over the top of the carrier, whereupon it is taken by pull-out rolls or the like.

The carrier is transversely disposed and is preferably in the form of a sector of a cylindrical drum, having arcuate surfaces which cooperate with wheels adjacent the carrier to seize the sheets while still in the grasp of the second gripping unit and thereafter advancing the sheets, the carrier and the wheels acting as pullout rolls.

One of the objects of the invention is the provision of simplified sheet feeding means disposed at the front end of a sheet to be fed.

Another object is the provision of sheet feeding means operable under a stream of fed sheets to seize the sheets of a supply in succession and transfer them under positive control to the stream.

Another object is the provision of a feeding carrier which may be disposed above and transversely of a supply of sheets, and which is adapted to lift the front edge of the top sheet off the supply and then raise it and carry it over the top of the carrier into a stream of sheets.

A further object is the provison of two sheet gripping units adapted to bodily rotate in the same direction around the same center and operable to transfer a sheet from one to the other of said units during their rotation.

A further object is the provision of a sheety gripping sucker adapted to grasp a sheet by its upper surface and transfer it to sucker means for gripping the sheet by its undersurface, thelatter means serving also to raise the sheet further and advance it.

Still another object is the provision of driving means for imparting the desired movements to the elements of the feeder.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which:

Fig. 1 is a fragmental plan View of a sheet feeder embodying the invention.

Fig. 2 is a fragmental end elevational view of the same.

Fig. 3 is a sectional view taken on a vertical plane extending parallel to the direction of sheet travel, the feeder frame being omitted, and

Figs. 4 to 15 inclusive are diagrammatic end views of the feeding carrier, showing the parts as they progress through a complete revolution of the carrier in twelve 36 stages.

Referring particularly to Fig. l, the side frame members of the feeder are shown fragmentally at and 2l. Conventional means are provided for supporting a pile P of sheets. A drum carrier 22 extends transversely of the machine directly above the forward edge of pile P. This carrier as herein illustrated consists of a cylindrical metal shell with end walls 23 and 24, the cylindrical wall having therein a gap 25 for a purpose which willpresently appear.

Frame member Y2li may have aligned bosses 26 and 21 on opposite surfaces thereof, and through these bosses and the frame member itself a bore 28 is formed, constituting a bearing for a cylindrical element 29 which carries a plate 34 inside the frame, while outside the frame'it carries a gear 3l and a cam 32. Gear 3l is driven by any suitable means from the machine to which sheets are to be fed. Plate 30 is secured by any suitable meansto the end Wall 23 of the carrier.

At the opposite side of the machine end wall 24 of the carrier has attached thereto by means of screws 33 or the like a plate 34 which constitutes the rotating element of a fluid valve. Plate 34 is bored centrally to receive a trunnion 35 integrally formed with end wall 24 and rotatably 'mounted in the frame member 2l. A thrust plate 35 is secured to the end of trunnion 35 `by machine screw 31. Between a boss 33 on frame member 2l and the rotating plate 34 there is a fixed annular valve plate 39 which may be held against rotation by screws 40 or equivalent means.

Within the cylindrical element 29 there vare bushings 4i which form bearings for a shaft 42, hereinafter called the main shaft. At the outer endof this main shaft there is keyed a pinion 43, and at its inner end within the hollow drum carrier there is a gear 44. Pinion 43 meshes with a gear sector 45 that is mounted to oscillate about a stud 45 anchored in frame member Z. Sector 45 is oscillate-dby means of a roller follower' 4'! mounted upon the sector arm and running vupon cam 32. Follower 4l may be held against its cam 32 by any suitable spring means, not shown.

In bearings in the end walls 23 and 24V of the carrier I mount two hollow shafts 5l? and 5! parallel to mainshaftr42. Each of these hollow shafts carries one or more sheet-gripping units, illustrated herein as sucker heads, one only for each shaft being illustrated. As shown herein a unit 52 on shaft 55 is disposed opposite a unit 53 on shaft 5|. These units or heads may if desired be disposed in staggered arrangement, that is, so as to engage different pcrgions of a sheet.

A single pair of such units may be suliicient for small sheets, but where larger sheets are to be handled, two or more pairs of units 52 and 53 are employed at points properly spaced transversely of the machine. Unit 52 preferably carries a pair of flexible rubber suckers 54 connected with the interior of hollow shaft by..a port 55, a cavity 55 and a pair of passages 5l. Unit 53 as herein illustrated is formed of metal exclusively and is provided with a plurality of aligned passages 58 which are connected with a cavity 59, the latter being in communication through a port 60 with the hollow interior of shaf t 5 l.

Shafts 50 and 5I have pinned thereto gears 6I and 62 respectively, these gears being of the same Ipitch diameter as gear 44. Mounted in the end wall 23 of the carrier and projecting inwardly into the carrier there are two stub shafts 63 and Shaft 64 carries a double gear 66, one element of which meshes with gear 44 and the other element of which meshes with gear 62 on shaft 5I. Shaft 53 carries a single -gear 65 which meshes with gear 44 and with gear 6i on shaft 50. Gears 55 and 65, being merely intermediate gears., may be of any suitable pitch diameter but as shown they are of the same diameter as gears 44, 6I and 62.

Revolving plate 34 is provided with ports 10 and 1I which register during their rotation respectively with arcuate grooves l2 and 'i3 formed in the face of fixed plate 39 and communicating with passages 12 and 13' in plate 39, these latterpassages leading to an annular groove 14 in the other face of the plate with which a conductor 'l5 communicates, this conductor being connected with the intake end of an air-pump or vacuum chainber, not shown. The plates 34 and 39 therefore constitute valve means for controlling the suction in hollow shafts 50 and 5i; Located above carrier 22 in position to cooperate with the arcuate surface thereof is a wheelt supported for free rotation in suitable bearings, not shown.

Operation- Shaft 42 with its gear 44 remains stationary except as it isvoscillated by sector and pinion 45, 43. Carrier 22, being xed with respect to gear 3 I, turns continuously counterclockwise, as seen in the drawings. Gears 65 and 66 therefore move like planet gears around a sun gear 44, except as their movement is altered by the oscillation of gear 44 due to the effect of the oscillations of sector 45 and pinion 43. The term turning as applied to shafts.50 and 5l or the sheet grippers 52 and 53 carried thereby is used in a general sense covering either rotation or oscillation or oscillation superimposed upon rotation. If gear 44 were allowed to remain stationary the gears 65 and 66 would roll evenly around gear 44 and by virtue of their engagement with gears 6I and 62 would rotate each of these gears one complete revolution clockwise around their respective centers while those centers were traveling one complete revolution counterclcckwise about the center of gear 4.4. Under such conditions, the gears 6I, 62 and their respective units 52, 53 would travel bodily around the center of rotation of gear 44 and carrier 22 but would remain always in fixed position with, relation to the vertical. For example, assuming the parts to be yin the position of Fig. V3 yand gear 44 to be held stationary, the suckers 54 wouldremain` disposed vertically downward .from .shaft 5D. and suction passages 58 would remain disposed vertically upward from shaft 5I v,during their travel around gear 44.

The paths. of travel of .thesuction heads are altered from that just described by the .oscillattion of gear 44 through the action of cam 32 and sector 45. The oscillations of gear 44 are of course transmitted through gears 65, 66, gears 6I, 62, shafts 50, 5l to units 52, 53, and these oscillations are superimposed upon the rotation produced by the sun and planet arrangement. Cam 32 is so shaped that the units 52, 53 oscillate through an angle extending somewhat less than 90 degrees on each side of the vertical, the amount of oscillation and the timing thereof being chosen to produce movement such that a point at the center of one of the suckers 54 follows approximately the path designated A in Fig. 4 and a point at the mouth of one of the suckers 58 follows approximatey the path designated B in Fig. 4. The various stages in this movement are illustrated in Figs. 4 to 15 inclusive.

In Fig. 4 the suckers 54 have just descended to the top of pile P or to a point above the pile close enough to attract and grip the top sheet of the pile. In Fig. 5 the carrier has turned through 30 from the position of Fig. 4, thereby moving hollow shaft 50 rearwardly with respect to the direction of feed. At the same time shaft 50 has turned clockwise through a sufficient arc to roll up the forward edge of the gripped sheet and thereby insure its separation from the sheet next below. The separating action may be assisted by fluffing air if desired in a manner that will be well understood by those skilled in the art. In this figure the front edge of the sheet has been drawn a short distance into the carrier through the gap 25. In the Fig. 6 position the two hollow shafts 50 and 5I are turning clockwise and the adjacent surfaces of units 52 and 53 are moving in opposite directions, the arcs of movement of the suckers about their centers ybeing closely adjacent to each other and the forward edge of the sheet extending further into the carrier. In Fig. 7 the suckers 54 and 58 have come into alignment but the sheet is still held by sucker 54. The front edge of the sheet now extends into the carrier the maximum distance. In Fig. 8 the relative positions of units 52 and 53 are substantially the same as in Fig. 7, cam 32 functioning to maintain them in this relation, but the advancing carrier has lifted the sheet somewhat further. During the 1time the suckers are thus traveling together about the centers of the carrier, suction in suckers 54 is relieved and suction is established in suckers 58, so that the sheet is transferred from unit 52 to unit 53, it being noted that unit 53 engages the underside of the sheet. Where the units 52 and 53 are in alignment the breaking of suction in suckers 54 and establishing of suction in suckers 58 are substantially simultaneous, whereby the sheet is continuously under positive control and positive transfer of the sheet is obtained. Where the units 52. 53 are not in alignment the suction in suckers 58 is preferably established before suction in suckers 54 is broken, so that both sets of suckers grip the sheet for a time during the transfer.

In Figs. 9, 10, 11 and 12, unit 53 rises gradually, meanwhile turning clockwise about its center, thus lifting the forward edge of the sheet and moving it outwardly toward the surface of the carrier.` In the Fig. 13 position the suckers 58 have swung up through the gap 25 to a position substantially flush with the surface of the carrier. As unit 53 approaches the Fig. 13 position its motion is such that suckers 58 are traveling at substantially the same linear speed as that of thev arcuate surface of carrier 22. Shortly after the Fig. 13 position, and while suckers 58 are still gripping the sheet and traveling at carrier speed. the carrier presses the sheet against the underside of idler` roll 80, after which suction is broken in suckers 58 and they release the sheet. The driven carrier 22 and the idler roll 80 together constitute sheet pull-out means, and from this point on the sheet is in control of these pull-out rolls. The driving effect of carrier 22 is of course limited by the length of the arcuate surface of the carrier. In practice other conveying devices such as tapes 8|, cooperating idler rolls 82, and a feed board 83, shown in Fig. 4, are provided which receive the sheets from carrier 22 and roll 8D and convey them further toward the machine being fed, the stream of sheets being indicated in this gure by the broken line S. The diameter and the speed of revolution of carrier 22 are such'that the sheet is moved at the required speed. In the case of a sheet by sheet'feeder this speed would ordinarily be approximately the same as the surface speed of the printing cylinder of the press to which the sheets are fed, whereas for stream feeding it would be a fraction of that speed.

It will be noted that the unit 52 has swung gradually outward toward gap 25 in passing from the Fig. 10 position to that of Fig. 14 and that in the Fig. 14 position the sucker 54 is beginning to project through the gap. At the time of the Fig. l5 position follower 41 is at the high point of the cam 32 and stands as indicated by the broken line circle 4l', Fig. 3. Thereafter the follower 41 runs down rapidly from the high point of the cam to the full line position of Fig. 3 which corresponds with the position of the sucker head in that figure and in Fig. 4, and the sucker unit 52 swings rapidly in the clockwise direction from the Fig. 15 position to that of Fig. 4. Then the follower 41 continues its rapid travel down to the low point of the cam and position 41" of Fig. 3, which corresponds to the positions of the sucker heads illustrated in Fig. 6, the sucker unit 52 continuing its clockwise movement to cause the rolling up and lifting of the forward edge of the sheet. This rapid swing of the sucker unit 52 while the axis of the hollow shaft 50 moves through the lower portion of its travel results in a generally cycloidal path of sucker movement, the center of the sucker travelingalong the cusp of path A as shown in Fig. 4 while the face of the sucker assumes different angles with the top of the pile.

From the foregoing it will be seen that each sheet is gripped on its upper surface by a-depending sucker, simultaneously rolled up and lifted, and presented to an upwardly extending sucker which follows along after the depending sucker, when the two suckers come into alignment in approximately tangential relation. It is then carried by the second sucker upward and forward and placed in the bite between the carrier and the idler roller. The next sheet is gripped and raised and fed beneath the preceding one, and with continued operation a stream of sheets is formed and caused to advance above the carrier. Inasmuch as the sheets, after being separated and lifted, are handled by their undersurfaces, and inasmuch as the stream proceeds above the carrier and the suckers and their driving connections are contained within the carrier, difficulties heretofore encountered in efforts to stream feed sheets from the front of a pile are avoided. Control of the sheets by theirz front edges, permitting them torbe pulled 4forward instead of `pushed or floated, is obviously advantageous.

Having thus described my invention, I claim:

l. In a sheet handling apparatus, a rotating carrier having its axis transverse to the direction of feed, two angularly'separated sheet gripping units pivotally mounted in said carrier, one of said units being adapted to take a sheet along a transverseedge thereof andmove said edge inwardly in the general direction of the carrier axis, means for turning said units about their pivots during rotation of the carrier, said turning means causing the second unit to approach the gripped edge of the sheet, and means for causing the first unit to release the'sheet and the second unit to grip it,'said turning means causing the second unit to carry the gripped edge of the sheet away from the axis of the carrier at a point angularly spaced from the taking point.

2. In a sheet handling apparatus, a rotating carrier 'having its axis transverse to the direction of feed'and having an Varcuate surface portion,

'two angularly separated sheet gripping units pivotally mounted in said carrier, one of said units being adapted to take a sheet along a transverse edge thereof vand move said edge into the space surrounded by the path of said arcuate portion, means for turning said units about their pivots during rotation of the carrier, said turning means causing the second unit to approach the gripped edge of the `sheet within said path, means for causing the rst unit to release the sheet and the second unit to take it, said turning means causing the second unit to carry the gripped edge of the sheet to the arcuate surface of the carrier, and means for pressing the sheet against said arcuate surface, said second unit functioning to place the sheet gripped thereby into the bite between said arcuate surface and said pressing means.

3. In sheet handling apparatus, a rotating carrier, a first sheet gripper unit pivotally mounted in said carrier, means for operating said first gripper unit to cause it to seize a sheet presented thereto and lift the same, sheet conveying means, a second sheet gripper unit pivotally mounted in said carrier, and means for operating said second gripper. unit to cause its gripping portion to be disposed `opposite the gripping portion of said first unit with the lifted edge of the sheet therebetween for transferring the sheet from the rst unit to the second, and to cause the latter unit to ransfer the sheet to said conveying means.

4. In a sheetfeeder, a rotating carrier, two angularly separated suckers in said carrier, and operating means for said carrier and suckers causing one sucker to grip a sheet by its upper surface near its forward edge, lift it oif the pile .and release it, and causing the other sucker to grip the release sheet by its undersurface at the time of its said release and advance it, whereby it may be taken by sheet pull-out means and moved forwardly over said carrier.

5. In a stream feeder for advancing sheets from a supply by their forward edges, a rotating carrier disposed above the forward edge of the supply, two angularly separated sheet grippers in :said carrier, and operatingmeans for said carrier and grippers causing one gripper while below the-'axis of the carrier to travel rearwardly across the top sheet of the supply, lift it off the supply and release it, and causing the other gripper to grip said lifted sheet and while above the axis of the carrier advance it and release it, Y

and pull-out means to take the advanced'sheet, saidoperating means causing the next sheet 'of the supply to be taken, lifted, advanced and fed into said pull-out means beneath the preceding sheet.

6. In a sheet feeder, a rotating carrier, two: angularly lseparated sheet gripping units mounted in said carrier to oscillate about .axes parallel to the carrier axis, and operating means forsaid carrier and units causing'any givenpoint on the carrier to travel rearwardly when beneath'the carrier axisand forwardly when above ,said axis, and causing one of said units as it movesrearwardly to grasp a sheet simultaneously lift it;and roll it rearwardly and then release it, and causing the other unit to grasp the sheet at the moment it is released and while moving forwardly advance it over said carrier.

'7. In a sheet feeder, a rotating carrier, two angularly separated sheet grippers mounted in said carrier to oscillate about axes parallel to the carrier axis, rand operating means for said carrier and grippers causing any given point on the carrier to travel rearwardly relative to the direction of sheet feed when beneath the carrier axis and vforwardly when above said axis, causing one of said grippers as ittravels rearwardly to move in a cycloidal path downwardly from the carrier to rgrasp a sheet, then upwardly towardthe axis of the carrier and then to release the sheet, and causing the other gripper to grasp the sheet at the moment it is releasedand'while moving forwardly to advanceit over the said'carrier.

8. In a sheet feeder, acarrier having 'an arcuate surface portion, means for rotating said carrier to cause the upper surface `thereof to turn forwardly relative to the direction of sheet feed,'two angularly separated sheet gripper units in said carrier, operating means for said carrier and gripper units causing one gripper unit as it moves rearwardly to grip a sheet, lift it andrelease it, and causing the other gripper unit to grip the lifted sheet at the moment of its release and advance it over the carrier, and a pull-out roll cooperating with Asaid arcuate surface portion of the carrier for advancing the sheet 'after it is released by the second gripper unit.

9. In a sheet feeder, a drum carrier having a gap in its cylindrical'wall, two angularly lseparated sheet grippers mounted in said carrier to oscillate about axes parallel to the carrier'axis, operating means for said carrier and grippers causing any given point on the carrier to travel rearwardly relative to the direction ofsheet feed when beneath vthe carrier axis and forwardly when above said axis, and causing one `of said grippersas it moves rearwardly to grasp the forward edge of a sheet, lift itand draw it into the carrier through said gap and release it, and causing the other gripper to grasp the sheet and while moving upwardly and forwardly to project said forward edge outwardly through said gap` to the surface of the carrier.

l0. In a stream feeder for advancing sheets from a supply by their forward edges, a rotating carrier disposed over the forward edge 4of the supply, two angularly separated suckers in said carrier, and operating means for said carrierand suckers causing one sucker while below the axis of the carrier to travel rearwardly across the top sheet of the supply, lift it oif kthefsupply and release it, and causing the other sucker to Vgrip said lifted sheet by its undersurface and Vwhile above the axis, of the `icarrierladvanceit andrelease it, and pull-out means to take the advanced sheet, said operating means causing the next sheet of thesupply to be taken, lifted, advanced and fed into said pull-out means beneath the preceding sheet.

11. In a sheet feeder, a rotating carrier, two angularly separated suckers mounted in said carrier to oscillate about axes parallel to the carrier axis, and operating means for said carrier and suckers causing any given point on the carrier to travel rearwardly relative to the direction of sheet feed when beneath the carrier axis and forwardly when above said axis, causing one of said suckers as it travels rearwardly to move in a cycloidal path downwardly from the carrier to grasp a sheet, then upwardly toward the axis of the carrier, and then to release the sheet, and causing the other sucker to grasp the sheet by its undersurface and while moving forwardly to advance it over the said carrier.

12. In a sheet feeder, a carrier having an arcuate surface portion, means for rotating said carrier to cause the upper surface thereof to turn forwardly relative to the direction of sheet feed, two angularly separated suckers in said carrier, operating means for said carrier and suckers causing one sucker as it moves rearwardly to grip a sheet by its upper surface, lift it and release it, and causing the other sucker to grip the lifted sheet by its undersurface and advance it over the carrier, and a pull-out roll cooperating with said arcuate surface portion of the carrier for advancing the sheet after it is released by the second sucker.

13. In a sheet feeder, a drum carrier having a gap in its cylindrical wall, two angularly separated suckers mounted in said carrier to oscillate about axes parallel to the carrier axis, operating means for said carrier and suckers causing any given point on the carrier to travel rearwardly relative to the direction of sheet feed when beneath the carrier axis and forwardly when above said axis, and causing one of said suckers as it moves rearwardly to grasp the forward edge of a sheet, lift it and draw it into the carrier through said gap and release it, and causing the other sucker to grasp the sheet by its undersurface and while moving upwardly and forwardly to project said forward edge outwardly through said gap to the surface of the carrier.

14. In a sheet feeder, a main shaft, a carrier rotatable about said shaft, and means for grasping and moving a sheet comprising two oscillatable shafts mounted in said carrier parallel to said main shaft, a sheet gripper on each of said oscillatable shafts, a gear on said main shaft Within said carrier gear means meshing with said main shaft gear for turning said oscillatable shafts, a cam mounted to rotate with said carrier, a pinion on said main shaft externally of the carrier, a gear sector meshing with said pinion, a follower on said sector runningv upon said cam and oscillating said sector and thereby said main shaft, and means for imparting rotation to said carrier, said cam being so formed that said grippers swing through arcs while their shafts revolve bodily about said main shaft.

15. In a sheet feeder, a main shaft, a carrier rotatable about said shaft, and means for grasping and moving a sheet comprising two oscillatable shafts mounted in said carrier parallel to said main shaft, a downwardly directed sucker on one of said oscillatable shafts, an upwardly directed sucker on the other of said oscillatable shafts, a gear on said main shaft within said carrier, gear means meshing with said main shaft gear for turning said sucker shafts, a cam mounted to rotate with said carrier, a pinion on said main shaft externally of said carrier, a gear sector meshing with said pinion, a follower on said sector running upon said cam for oscillating said sector and thereby said main shaft, and means for imparting rotation to said carrier, the arrangement being such that while said sucker shafts revolve bodily around said main shaft the suckers oscillate about their shafts while they continue to extend downward and upward respectively.

16. In a sheet feeder, a main shaft, a carrier rotatable about said shaft, and means for grasping and moving a sheet comprising two oscillatable shafts mounted in said carrier parallel to said main shaft, a downwardly directed sucker on one of said oscillatable shafts, an upwardly directed sucker on the other of said oscillatable shafts, a gear on said main shaft within said carrier, gear means meshing with said main shaft gear for turning said sucker shafts, a cam mounted to rotate with said carrier, a pinion on said main shaft externally of said carrier, a gear sector meshing with said pinion, a follower on said sector running upon said cam for oscillating said sector and thereby said main shaft, and means for imparting rotation to said carrier, said cam being so formed that during rotation of the carrier said downwardly directed sucker and said upwardly directed sucker face each other momentarily, whereby a sheet may be transferred from one to the other.

17. In a sheet feeder, a rotating carrier, and means for grasping and moving sheets comprising two oscillatable shafts mounted in said carrier parallel with the axis thereof, a sucker on each of said shafts, one sucker extending downwardly from its shaft and the other extending upwardly from its shaft, said downwardly disposed sucker being adapted to take a sheet from the top of a pile of sheets, the arcs of movement of said suckers relative to their axes being substantially tangent to each other, and operating means for causing said suckers to come into alignment for transferring sheets from the downwardly extending sucker to the upwardly extending sucker, and means for taking sheets from the upwardly extending sucker.

18. In a sheet feeding mechanism, a revolving carrier, two sheet gripping units oscillatably mounted in said carrier about axes parallel with the carrier axis and angularly separated less than one of said units being adapted to grasp the forward edge of a sheet as the unit moves bodily rearward in the lowermost part of its travel and then to lift the sheet, and the other unit being adapted to grasp the lifted edge from a position beneath the sheet and to raise and advance it over the top of the carrier, and driving means for bringing said units into sheet transferring relation during their upward bodily travel about said carrier axis.

19. In a sheet feeding mechanism, a revolving carrier, two sheet gripping units oscillatably mounted in said carrier about axes parallel with the carrier axis and angularly separated less than 180, a sucker in each of said units, the sucker in one of said units being adapted to grasp the forward edge of a sheet by its upper surface as the unit moves bodiy rearward in the lowermost part of its travel and then to lift the sheet, and the sucker in the other head being adapted to grasp the undersurface of the lifted edge and` raise the same and advance the sheet over the top of the carrier, driving means for bringing said units into sheet transferring relation during their upward bodily travel, and means `for controlling` suction in said units to eifect'said transfer.

20. In sheet handling apparatus, a rotating carrier disposed transversely to the direction of feed. two angularly separated sheet gripping units pivotally mounted in said carrier, one of said units being adapted to take a sheet along a transverse edge thereof, and means for turning said units about their pivots during rotation of said carrier for bringing the gripping portions of said units simultaneously into the plane of the said pivots for transferring a sheet from said sheet taking unit to vthe other unit.

21. In a sheet feeder, a main shaft, a carrier rotatable about said main shaft, means for rotating said carrier, a second shaft mounted in said carrier. parallel to said main shaft, a first sheet gripper on said second shaft, a gear on said main shaft, gear means meshing with said Amain shaft gear for rotating said second shaft in a direction opposite to that of the carrier, one revolution for each revolution of the carrier, means for oscillating said main shaft and thereby superimposing upon the rotary motion of said second shaft a motion of oscillation, said oscillating means functioning to cause said first gripper to move outwardly from. the carrier axis .for

`grasping an edge vof a sheet and then to move the vgrasped edge inwardly toward the axis of rotation of said carrier, a secondy sheet gripper mounted in the carrier adapted to take the grasped edge of the sheet from said first gripper and move it outwardly away from the axis of rotation of the carrier and means for taking the sheet vfrom said second gripper and conveying it away from the carrier.

v22. In a sheet feeder, a main shaft, a carrier .rotatable about said main shaft, meansfor rotating said carrier, a second shaft mounted `in said carrier parallel to said main shaft, a first ,sheet .gripper on saidsecond shaft, a gear-on said main shaft, gear means meshing with `said main shaft gear for rotating said second shaft in a direction opposite tov that of the carrier, one revolution for each revolution of the carrier, a cammoun-ted to rotate with said carrier, a pinion on said main shaft, a toothed sector meshing with said pinion. a follower on said sector cooperating with said cam for moving said sector back and forth to oscillate said main shaft, and thereby superimpose upon the rotary motion of said second shaft 'a motion of oscillation, said oscillating means functioning to cause the sheet gripping portion ofV said first gripper momentarily to occupy a substantially stationary position for grasping an edge of a sheet and then to move the grasped edge inwardly toward the Aaxisl of rotation of said carrier, a second sheet gripper mounted in the carrier adapted to take the grasped edge of the sheet from .said rst gripper and move it outwardly away `from the axis of the carrier, 'and means for taking the sheet from said second gripper and conveying it away from the carrier.

23. In sheet handling apparatus, a rotating carrier, two angularly separated sheet grippers in said carrier, and operating means for said carrier and grippers causing one ,gripper to grip a sheet at its forward Vedge, move said edge inwardly toward the axis of the carrier and release it, and causing the other gripper `to meet the first gripper and to lgrip the forward edge of said released vsheet at the time of its said release and carry said'forward edge outwardy away from the axis of said carrier and release it, and means for forwarding the sheet away from said carrier.

HOWARD A. PRITCHARD.

REFERENCES CITED The following referencesv are of record in lthe file of `this patent:`

, UNITED STATES VPAIENTI'S Number

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