US2309979A - Sheet feeder - Google Patents

Description

Feb. 2, 1943. H. A. PRlTCHARD SHEET FEEDER 2 Sheets-Shet 1 Filed May 8, 1940 A INVENTOR. f/ovmeo ,9. "Pena/M20 MW W ATTORNEYfi Feb. 1943.. H, A. PRITCHARD H 2,309,979

' SHEET FEEDER Filed May 8. 1940 2 Sheets-Sheet 2 INVENTOR. Hoomeo A! Pare/men Y 12% f/wm 1K ATTORNIzlYfi Patented Feb. 2, 1943 OFFICE SHEET FEEDER Howard A. Pritchard, Hiram, Ohio, assignor to Harris-Seybold-Potter Company, Cleveland, Ohio, a corporation of Delaware Application May 8, 1940, Serial No. 334,013

20 Claims.

This invention relates to sheet feeders for printing presses or other sheet handling machines and has particular reference to mechanism in which the sheets are forwarded in lapped formation to a position'of rest from which they are taken into the machine by a variable speed transfer mechanism. The invention provides means whereby the variable motion of such a transfer mechanism is utilized to determine or to control the speed of the foremost lapped sheet as it approaches its position of rest.

When sheets are advanced in the conventional manner to a position of rest against front registering stops there is danger of the front edge buckling or rebounding at the stops so that an out of register condition is obtained. This is true even when the sheets are advanced at relatively slow speed in the form of a stream of lapped sheets with each sheet partly overlying the next following sheet. Furthermore, successive sheets are frequently displaced slightly forward or backward from their desired positions as they are conveyed toward said stops. At other times their front edges are not in true alignment with said stops and the sheets must be straightened.

Accordingly it is among the objects of this invention to provide means for accurately and gently presenting a sheet to front registering stops.

Another object is to provide mechanism of the type described which willserve to straighten the sheets as; they approach a position of rest.

Another object is to provide means for vary ing the speed of presentation of lapped sheets to a position of rest.

Another object is to provide in combination with a variably moving sheet transfer device, means for slowing down the foremost sheet of a stream of lapped sheets as the latter approaches stationary position against stops adjacent said transfer device, which means shall depend either for the character of its movement or for its actuation upon the operation of said transfer device.

Another object is to provide slowdown means which shall have speed proportional to but less than the speed of the transfer device.

Another object is to provide means for feeding sheets in lapped relation to a position of rest adjacent to a variably rotating transfer device at a speed dependent upon the variations of speed of the transfer device.

Another object is to' provide mechanism of the type described which will be simple in construction and effective in operation.

Other objects will appear from the following description and drawings in which:

Figure 1 is a diagrammatic side elevational view of the pertinent parts of a sheet feeding mechanism according to the invention.

Figures 2 and 3 are detail views in different positions of one form of the device employing suction wheels for controlling the sheets.

Figures 4 and 5 are similar views of another form of the device employing rotating slowdown stops,

Figure 6 is a view along the line 6-6 of Figure I I 4 showing means for rapidly withdrawing the rotary stops or slowdowns from the path of a sheet about to be transferred, and

Figure 7 is a fragmental View, similar to Fig. 4, showing a modification.

Referring to Figure 1 the sheets to be fed to the printing or other machine are taken from a pile ID by well known devices such as suckers H and conveyed forward into the bite of advancing rollers I2 and I3 which further advance the sheet. As illustrated, roller I3 is driven with such speed as to cause each sheet to be only partially withdrawn from the pile at the time the next sheet is fed between the rollers l2 and I3, thus producing a stream of lapped sheets inthe familiar manner.

Trained around roller [3 and a forwardly disposed roller I4 are tapes l5 which convey the sheets toward the press. Rider rollers I6 serve to hold the. sheets against the tapes to insure their advancement. These sheets are conveyed to a position of rest against stops I! where they are further registered in the usual manner and from this position of rest they are taken by grippers 25 on a variably moving transfer device l9 and transferred thereby to grippers 20 of a uniformly rotating cylinder, such as the impression cylinder 2|, of a printing or other sheet handling machine.

Referring to Figs. 2 and 3 the transfer device be employed to produce the desired rotation of the transfer device, such mechanisms being known in the art, as for example in Harrold et al. Patent No. 2,192,908.

The transfer device is provided with grippers 25 mounted on shaft 26 all arranged in known manner to be withdrawn into the transfer device sufficiently toppass and avoid interference with a sheet approaching the front stops and to move outwardly and into gripping engagement with the sheet while the transfer device is stationary. Mechanism for this purpose also is disclosed in the said Harrold 'et al. patent.

The sheets are advanced toward their position of rest over a feed board 21 and into contact with the stops H which are mounted on shaft 28 extending across the machine and operated in the usual manner to engage the forward edge of a sheet at the proper time and to withdraw from the path of the sheets when a sheet is about to be transferred to the cylinder 2|.

In the form of the invention illustrated in'Figs. 2 and 3 I provide a slot 29 in the feed board 21 to accommodate suction wheels 30, of which there may be two or more spaced transversely across the machine, mounted on shaft 31. These suction wheels are provided with perforations 32 in their rims which register successively with pockets 33 in arms 34, which pockets are connected by tubes 35 to a source of suction, whereby suction may be intermittently produced in the pockets 33 and consequently in the perforations 32 of the rims of the suction wheels as the perforations register successively with the pockets 33. The arms 34 may be supported in any desired manner and the usual suction producing and controlling mechanism may be connected to the tubes 35.

At a point preferably outside the frame of the machine and in such position as not to interfere with shaft 28 a gear 36 is secured to shaft 3| and arranged to mesh with a gear 3'! secured to shaft 22 of the transfer de'vice. By this gearing the shaft 3| and suction wheels 30 are given rotary movement conforming to that of the transfer device. Thus as the I transfer device decelerates, the suction wheels 30 also decelerate, and as the transfer device moves at the speed imparted to it by its driving mechanism, the suction wheels partake of a movement in the proper direction proportional to the movement of the transfer device. The proportions of the gears 36 and 31 may be varied according to the result desired. For example, while I have illustrated the device in connection with stream fed sheets it is apparent that it may be employed with sheets fed in entirely separated condition, and in this latter case the proportions of the gears 36 and 31 would be preferably such as to produce a surface speed of the suction wheels 30 approximately equal to the speed of the sheets at the time the wheels become effective, their speeds then decreasing to zero as the transfer device decelerates. Preferably, however, and in connection with stream feeding as disclosed herein, the gears 35 and 31 are so proportioned as to produce an initial surface speed of the suction wheels 30 which is a fraction of the maximum speed of the transfer device and approximately equal to the speed of the sheets of the stream as they are conveyed by the tapes l5.

In Fig. 2 the positionof the transfer cylinder at the stationary point in its operation is illustrated in full lines, while its position at the end of its period of acceleration is indicated in dotted of the period of deceleration. Between the dotted line position of Fig. 2 and the position of Fig. 3 the transfer cylinder rotates at a constant rate witha peripheral speed equal to that of the impression cylinder.

With the parts in the position of Fig. 3, where the transfer deviceis just beginning to decelerate, suction is applied to the suction wheels 30 so that they engage the undersurface of the foremost sheet of the stream while the suction wheels and sheets are moving at approximately the same speed; From this point on the transfer device decelerates to zero and the suction wheels 30 likewise decelerate to zero and as a consequence slow down the sheet as the latter approaches the stops H. The suction is preferably cut off just before the sheet reaches the front stops l1, and the sheet is then urged into final registered position against the stops by the continued forward movement of the stream.

Obviously the timing of the suction may be such that instead of its being cut off slightlybefore the sheet reaches the front stops, as preferred, it will be cut off precisely at that point or slightly thereafter. In bothof the latter cases the sheet will be under the control of the suction wheels from the time they engage it until it strikes the stops, and after the sheet is against the stops the suction wheels may act momentarily to hold it there, dependent upon the exact moment when the suction is terminated, and the movement of the stream functions also for that purpose. In any event the effect of the suction wheels is to slow the sheets down so that they are presented gently and accurately to the front stops.

After the sheets have been stopped and any additional registering operations have been performed, the grippers 25 close upon the front edge of the sheet, and thereafter the transfer device begins to accelerate and speeds up the sheet to the speed of the impression cylinder and transfers the sheet to the latter cylinder, the stops II meanwhile having been dropped out of the way of the sheets.

In the'form of device illustrated in Figs. 4 to 6 inclusive the sheets as they approach their positions of rest are engaged by two or more rotating stops 40 keyed to a shaft M which is driven by gears 42 and 43 that correspond in purpose to gears 36. and 31 in the other form of the invention. The stops 4!] pass through slots 44 in the feed board 21 just in advance of the forward edge of the sheet, which soon thereafter catches up with the stops. The stops then decelerate and the sheet comes to rest against them in the proper position to be taken by the grippers of the impression cylinder. These stops therefore perform the double function of slowing down as well as front registering the sheets.

The gears 42 and 43 are inthis form equal in diameter so as to cause one complete rotation of the stops for each rotation of the transfer device, and the stops are preferably arranged at such a distance from the axis of shaft 4| that they move with a maximum peripheral speed slightly less than the speed of a sheet forwarded by tapes I5. Thus the stops 40 will be engaged by a sheet shortly after the position illustrated in Fig. 5 and the sheet will thereupon be slowed by the deceleration of the stops acting against the forwarding impetus of the stream. Thus the stops will cooperate with the stream to align or straighten the sheet as well as to slow it down.

As illustrated in Fig. a series of tongues 45 may be secured to the transfer device to cooperate with the feed board in confining the forward edge of thesheet tothe desired path.

An alternative construction is illustrated in Fig. 7 where stops of non-rotating character and of familiar design and operation, mounted on an oscillating shaft I28 are provided in addition to the rotating stops 40. In this case the parts are so arranged that the stops 40 move forward slightly beyond the position of stops I I1 before theirdecelerating motion terminates, so that the stops 40 act as slow-down means only while the front registration of the sheets is effected against stops Thereafter stops drop below the sheet path in a manner well known in the art.

In both of the'last described forms of the invention, in order to move the stops 4!] out of the path of the sheet when the latter has been gripped and starts forward from its stationary position, I provide a driving arrangement for the shaft 4| which permits it to be driven momentarily ahead of its gearing in order that the stops 40 may be withdrawn much more rapidly than they move at other times. This arrangement is illustrated in Figs. 4 and 6. The gear 42 which is retained on the shaft 4| by collar 46 is loosely mounted on the shaft and is resiliently connected thereto by spring 41, one end of which is secured to the gear 42 and the other end to a collar 48 which is keyed to the shaft 4|. Collar 48 carries a fixed stud 49 and the gear42 carries a pin 5|) which provide a positive drive between the gear and the shaft, the spring 41 providing a resilient connection which permits the shaft to rotate faster than the gear momentarily. Inside the frame F of the machine is a crank arm 5| keyed to shaft 4|, which crank arm carries a roller 52. A cam 53 is secured by bolts 54 to the transfer member disk 23. Cam 53 and roller 52 are so positioned as to be in substantial contact at the time the stops 40 are stationary so that as the transfer member begins to rotate after taking a sheet the cam 53 operates through the roller 52 and crank 5| to turn the shaft 4| ahead of its gear drive at a speed sufiicient to quickly carry the stops 4|] out of the path of the advancing sheet so as not to interfere with the forwarding of the latter.

It will be apparent that the invention may, if desired, be utilized to slow down the foremost sheet of a stream of lapped sheets while the same is still partly covered by the rear portion of a sheet being removed from the stream and transferred to cylinder 2|.

Other variations in the details of construction of the invention may be employed. For example the stops 40 instead of rotating about av single center may be secured to continuous bands carried around two centers, these bands being driven with appropriate speed to provide the desired slowing down operation.

It is known to provide an intermittent rotary transfer mechanism with stops mounted thereon which project into the path of sheets and slow them down. Such mechanism is employed with sheets fed at high speed in entirely separated condition as distinguished from stream feeding. Such stops are impractical for use in connection with stream fed sheets for the reason that a large space between successive sheets is required in order to permit the stops to pass through the path of the sheets in advance of their leading edges. It is apparent that by the present inven- .tion I have provided means for advancing and slowing down sheets as they approach stationwith stream fed sheets. As shown in Figs. 3 and 5 the advancing sheet is much farther along on the feed board than would be the case if slowdown stops were provided on the transfer member and therefore the sheets are enabled to reach their registering position earlier in the cycle and longer sheets may be fed. With respect I to Figs. 5 and 7, the stops 40 pass through the r path of the sheet earlier in the cycle than it would be possible for slow-down stops on the transfer cylinder to do. i I

Having thus described my invention'I claim:

1. In sheet feeding mechanism the combination of a variably moving sheet transfer member and separately mounted mechanism actuatedby variable movement of said member at a constant speed ratio to control the advance of sheets thereto.

2. In sheet feeding mechanism the combination of a non-uniformlyrotating sheet transfer member and separately mounted mechanism actuated by rotation of said member at a constant speed ratio for controlling the advance of sheets thereto. H

3. In sheet feeding mechanism the combination of variably moving sheet transfer mechanism and separately mounted sheet slowdown mechanism having variable movement dependent upon the movement of said transfer mechanism.

4. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member having a period of acceleration and one,

of deceleration and separately mounted sheet slowdown mechanism actuated by rotation of said transfer member during deceleration thereof.

5. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member having a period of'acceleration and one of deceleration and sheet slowdown mechanism driven at speed proportional to but different from the speed of said member during deceleration thereof.

6. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member having a period-of acceleration and one of deceleration and sheet slowdown mechanism driven at speed proportional to but less than the speed of said member during deceleration thereof.

'7. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member having a period of acceleration and one of deceleration and sheet slowdown mechanism actuated by rotation of said member at speed proportional to but different from the speed of said member during deceleration thereof.

8. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member and means for feeding sheets to a position of rest where they may be taken by said transfer member, said means being arranged to feed the sheets for at least a portion of their travel at variable speed different from the surface speed of said transfer member but dependent upon the speed variations of said transfer member. i

9. In sheet feeding mechanism the combination of an intermittently rotating sheet transfer member having a period of deceleration and means for feeding sheets to a position of rest where they may be taken by said transfer memher, said means being arranged to feed the sheets for at least a portion of their travel at variable speed proportional to but less than the variable surface speed of said transfer member during deceleration thereof.

10. In sheet feeding mechanism the combinationof a non-uniformly rotating sheet transfer member and means for feeding sheets in lapped relation to said member comprising means operating atvariable speed less than the surface speed of the transfer member and dependent upon th variations in speed of said non-uniformly rotating transfer member.

11. Inmechanism of the class described, a non-uniformly rotating sheet transfer member, sheet stops adjacent thereto, means for advancsheets in lapped relation toward a position of rest against said stops, and slowdown means mounted separately from said transfer member, actuated by rotation of said transfer member, and arranged to engage the foremost lapped sheet and slow the same down before reaching said stops.

12. In mechanism of the class described, a nonuniformly rotating sheet transfer member, sheet stops adjacent thereto, means for advancing sheets in lapped relation toward a position of rest against said stops, and slowdown means having speed dependent upon but less than the sur-- face speed of said transfer member during variable rotation thereof arranged to engage the foremost lapped sheet and slow the same downbefore reaching said stops.

13. In a mechanism of the class described, a uniformly rotating sheet receiving cylinder, a non-uniformly rotating sheet transfer member cooperating therewith, sheet stops adjacent said transfer member and means for advancing sheets in lapped relation to a positionof rest against said stops including means effective to advance the foremost lapped sheet at a speed proportional to the speed of said transfer member during a portion of the decelerating movement thereof.

14. In mechanism of the class described, means for feeding sheets along a given sheet path, a

non-uniformly rotating sheet transfer member on one side of said path, sheet stops at the for ward end of said path adjacent said transfer member, and slowdown means mounted on the opposite side of said path operatively connected with said transfer member adapted to engage a sheet traveling in said path and to move toward the stops at a speed proportional to the speed of the transfer member.

15. In mechanism of the class described, means for feeding sheets in lapped relation along a given sheet path, a non-uniformly rotating sheet transfer member on one side of said path, sheet stops at the forward end of said path adjacent said transfer member, slowdown means mounted on the opposite side of said path operatively connected with said transfer member adapted to engage the foremost one of said lapped sheets and to move toward the stops at a speed proportional to but less than the speed of the transfer member.

16. In mechanism of the class described, means for feeding sheets along a given sheet path, a non-uniformly rotating sheet transfer member on one side of said path, sheet stops at the forward end of said path adjacent said transfer member, a rotating suction wheel mounted on sheet in said path and to decelerate as the transfer member decelerates.

17. In mechanism of the class described, means for feeding sheets along a given sheet path toward a position of rest, a non-uniformly rotating sheet transfer member on one side of said path, a plurality of aligned rotating stops mounted on the opposite side of said path operatively connected with said transfer member and arranged to project through said path at proper times in advance of a sheet, said operative connections being such as to cause said stops to move at a speed proportional to but less than the surface speed of the transfer member, whereby each sheet is slowed down as it approaches said position of rest prior to being taken by said transfer member.

18. In mechanism of the class described, means for feeding sheets along a given sheet path toward a position of rest, a non-uniformly rotating sheet transfer member on one side of said path, a plurality of aligned rotating stops mounted on the opposite side of said path operatively connected with said transfer member and arranged to project through said path at proper times in advance of a sheet, said operative connections being such as to cause said stops to move at a speed proportional to but less than the surface speed of the transfer member, whereby each sheet is slowed down as it approaches said position of rest prior to being taken by said transfer member, and cam means actuated by said transfer member for rapidly withdrawing said rotating stops as the transfer member is about to move a sheet forward.

19. In mechanism of the class described, means for feeding sheets along a given sheet path toward a position of rest, a non-uniformly rotating sheet transfer member on one side of said path, slowdown means mounted on the opposite side of said path operatively connected with said transfer member adapted to engage a sheet traveling in said path and to move in the direction of sheet travel at a speed proportional to the speed of the transfer member, and sheet smoothers carried by said transfer member in advance of the point of engagement thereof with the front edge of a sheet.

20. In sheet feeding mechanism, the combination of a non-uniformly rotating sheet transfer member arranged on one side of the sheet path, and means for feeding sheets in lapped relation to said member comprising stops rotating about an axis located on the opposite side of the sheet path at a distance from the sheet path less than the radius of said transfer member, said transfer member and said stops being geared together for one-to-one rotation, whereby said stops are adapted to function as slow-downs for sheets moving through said path at a maximum speed less than the maximum surface speed of the transfer member.

HOWARD A. PRITCHARD.

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