US2221153A - Sheet feeder - Google Patents

Description

NOV. 12, 1940. D P SANFORD 2,221,153

SHEET FEEDER Filed May 5, 1939 2 Sheets-Sheet l El 25 22 Z5 z/ INVENTOR.

Sum um AEENT.

NGV- 12, 1940 D. P. SANFORD 2,221,153

SHEET FEEDER Filed May 5, 1939 2 Sheets-Sheet 2 INVENTOR.

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sheet fed immediately prior to the Patented Nov. 12, 1940 UNITED STATES SHEET FEEDER David P. Sanford, Union, N. J., assignor to American Type Foundersflncorporated, Elizabeth, N. J., a. corporation of New Jersey Application May 5, 1939, Serial No. 271,822

l 8 Claims.

This invention relates to improvements in sheet feeders and refers particularly to sheet feeders for printing presses.

There are some functions pertinent; to sheet feeding which are relatively non-positive. The reason for this is that in dealing with paper or like material which is generally of a fragile nature, and which mayvary considerably in size, texture, or condition, many operation variables arise which must be overcome by operation of light forces such as air blast and suction. Such light forces occasionally fail to function.

Results of such failure are that the feeder feeds out of time or may entirely miss taking a sheet in its cycle. It then becomes a problem to prevent further resulting interference or damage which might take place as feeding continues.

When feeding sheets partially lapped it has been found that for certain sheet sizes and for given feeding conditions wherein the sheet is picked up, transported to guides by a continuous conveyor, and held substantially stationary at guides during a registering period, the sheet fed next following a feedeiafmiss does not lap the lmiss$$ Rather, a gap is left between these sheets, and as the feeding operation continues, the leading edge of the sheet behind the gap catches up to and collides with the trailing edge of a sheet which has been stopped by and is held substantially stationary at guides.

The result of such a collision is that the sheet at the guides may be badly wrinkled and, as it proceeds through subsequent operations, it is liable to cause batter on a printing form or otherwise affect equipment because of its crumpled condition.

With the above in mind it is an object of this invention to provide a baille which will prevent sheets which are being transported on a conveyor from interfering with a previously fed sheet.

A further object of the invention is to provide a bailie which will be automatically operative when conditions are such that interference would take place and inoperative when no interference could take place.

Other objects of the invention are to provide a bafe which is composed of simple and effective instrumentalities which are not expensive to produce, which will operate on any normal range of sheets and which require little or no adjusting or servicing.

With these and other objects-win view which will be apparent throughout'the description, the

invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly deiinedby the appendedclaims, it being understood that such changes in the precise embodiment of the invention may be made ascome within the scope of the claims.

The accompanying drawings illustrate an example of physical embodiment of the invention constructed according to the best mode so far devised for the practic'l application of the principles thereof, and in which:

Figure 1 is a longitudinal section view through a portion of a sheet feeder for printing machinery illustrating the application of the invention thereto;

Figure 2 is an enlarged top plan view of baille mechanism applied above the feedboard;

Figure 3 is a longitudinal section taken on the line 3-3 in Figure 2; and

Figures 4, 5, and 6 are similar views to Figure 3 showing stages of operation.

Referring now to the accompanying drawings in which like numerals indicate like parts throughout the several views, the numeral l0 designates a. pile of sheets loaded on the platform of a sheet feeder and maintained in position by any suitable devices known in the art. Individual sheets are separated and fed in timed sequence from the top of the pile' to a conveyor by suitable feed-off devices as for example the mechanism described in my co-pending application Serial Number 232,443. Sheets 'are guided by the top guide 32, and bottom guide 3l until their leading edges reach continuous conveyor belts i4 trained over and driven by pulleys ll secured to the driving shaft l2 on one end of the conveyor, and idler pulleys 35 at the other end. Spaced drop rollers 23, loosely mounted for rotation in the brackets 22 fixed to a cross member I9 of the feeder frame, not shown, roll on conveyor belts I4 and serve to maintain sheets in frictional contact with the belts so that they will be carried down the feedboard I8 to two or more front guides 36 which hold the sheets substantially stationary against the frictional drive of the conveyor belts I4 for a predetermined register period. Guides 36 are then pivoted counterclockwise with shaft 33 by timed operating mechanism not shown to allow a sheet to pass on to subsequent operations. An example of such guide or gage operating mechanism is contained in U. S. Patent No, 1,452,466 issued to W. M. Kelly.

A framework, comprising two parallel rectanguiar bars 24 spaced apart by the rivet studs 34 is pivoted at one end to the brackets 22 at centers 2| and extends therefrom above the length of the feedboard serving as a mounting for additional drop rollers or for other devices known to the art which may be used for the purpose of maintaining sheets in frictional contact with the conveyor belts. Brackets 39, rigidly mounted to the other end of bar s 24, rest on the crossbar 40 extending over the feedboard I8 and mounted in any suitable manner at the sides of the feedboard.

One set of additional drop rollers 23' as shown in Figure 2 are loosely mounted for rotation on shaft 26 which is in turn mounted in and extends outwardly from bars 24 in aligned holes provided therefor. 'I'he rollers 23 are spaced away from bars 24 by collars 21 and anti-friction washers 31, and are maintained with slight axial freedom on the end of the shaft by similar anti-friction washers 31 held in place by pins 38. This arrangement allows rollers 23' to co-act with the conveyor belts I4 immediately therebelow to effect sheet driving.

A portion of the instrumentalities for checking the passage of sheets, as hereinafter described, are also mounted on shaft 26 in a position approximately central with the feedboard I8. A detector finger I6 of light weight construction is pivotally mounted on this shaft 26 and is spaced substantially midway between the bars 24 by the spacing collars 28. The yoke end of finger I6 is provided with aligned holes for loose mounting on the shaft 26 and the recess between the ears of this yoke is cut away to the surface 30, providing clearance and a contact edge t co-act with the baiile I fitted therebetween. Extending from this yoke end of the finger is a leaf portion which is rounded off in its lower extremity andsmoothed to slidingly contact the surface of sheets without scratching 0r tearing in operation.

The baille I5, of lighter weight construction than finger I6, fitted over shaft 26 within the recess of the detector finger I6 is also free to rock about this shaft independently of detector finger I6 until its flat under surface closely adjacent the pivot center strikes the line of contact on the detector finger I6 heretofore described. It will be perceived at this point that any clockwise rocking movement of the detector finger I6 will be transmitted to this baiiie I5 through this line of contact. The free end of the baille I5 is rounded and smooth to contact sheets traveling in a direction away from the supply pile to the discharge end of the conveyor. If desired, this end of baffle I5 may be slightly curved, depending upon conditions in feeding.

The plate I1 is located directly below baille I5 and detector finger I6 and is rigidly mounted in the feedboard I8. 'Ihis plate is flush on all edges with the board to prevent the leading edge of sheets which may be traversing the board from catching and wrinkling. A wedge-shaped raised portion on the plate I1 located near the left end of the plate Figure 3, includes an edge which tapers upwardly in the direction of sheet travel to a point slightly above the plane of the conveyor belts I4. This surface serves to raise sheets which may be sagging in between the conveyor tapes to an elevation above the feedboard surface to be operated on by the baiiie I5 as later described. On the opposite end of plate I1 is the rectangular cut-out portion 29 located to receive the rounded end of detector finger I6, the function of which will also be later described.

As indicated in Figure 3, the normal position of the detector finger I6, at a time when no sheets are being fed, is at an angle to the feed-board with its free end resting on the board in the cut-out, portion 29 of plate I1 and at a distance from guides 36 slightly greater than the length of the longest sheet fed. Inasmuch as the finger I6 is heavier than and overbalances theV baiiie I5, the contact edge of surface tends to hold the free end of baiiie I5 off the plate I1 so that there is a difference in elevation between' the lowest extremity of baille I5 and the peak of the raised portion 25 of plate I1. This allows each sheet traversing the feedboard on the conveyor belts I4 toward the discharge end to slide up the inclined surface 25 and to pass between the upper corner of this raised portion 25 and the lowest tip of the baille I5.

Upon moving. further along the leading -edge of a sheet contacts the detector finger I6 and, by means of the frictional drive of the conveyor belts, lifts the end of this nger until it can pass beneath it, as indicated in Figure 4. This, in turn, allows baiiie I5 to pivot counterclockwise since the contact edge of surface 30 on the detector finger has moved away from contact with bafiie I5.

As long as a sheet is passing beneath it, however, the baille has no effect on the sheet other than to rest on its top surface as it passes therebeneath. In the event, however, that there is a gap in feeding, the finger I5 will drop to the plate I1 as shown in Figure 5. which action will obstruct the path of sheets being conveyed from the supply pile.

Ii, on the other hand, the gap in feeding is large enough sothat no sheet reaches-baille I5 until after the trailing edge of a sheet fed before the gap has passed out from beneath the detector finger I6 as indicated in Figure 6, then finger I6 will again drop into the cut-out portion of plate I1, thereby overbalancing the bafile I5 and lifting it to a position which will allow sheets to pass by.

Inasmuch as the conveyor belts I4 move continuously it is apparent that if a sheet ahead is slowed or stopped such as by the front guides 36, a trailing sheet which does not partially lap the sheet ahead will continue to move and will collide with the sheet which has been stopped. If, however, the front guides raise up soon after the sheet is Stopped. as in the case with printing machinery wherein a sheet comes to register and is then taken by the impression cylinder, then there is only a short interval of time per cycle during which interference could be expected. Otherwise the leading sheet is rapidly removed bythe printing cylinder or other instrumentality and obviates interference.

Any gap between the trailing edge of a sheet and the leading edge of a succeeding sheet. which may result from improper feeding, and which is of such distance that the speed of the conveyor drive would cause the front edge of the succeeding sheet to abut or interfere with the trailing edge of the previous sheet being guided is critical. It is'this critical gap which determines the lengths and arrangement of baille I5 and detector finger I6.

In operation this device performs as follows: sheets fed in partially lapped relation pass down the conveyor without obstruction, the first sheet serving to raise the detector finger I6 and allowing the baille I5 to rest on the top of sheets passing therebeneath. When a gap in feeding occurs which is within the critical range described,

2,221,153 l the baille I catches the sheet behind and pre- Vents a further motion of this sheet down the feedboard.

When the gap is greater than the critical range or such that a sheet passes out from beneath detector finger I6 before a subsequent sheet reaches the baiiie, which condition would not cause interference, then the baiile I5 drops to the feedboard I8, but is raised againas detector finger I6 drops off the trailing edge of the sheet ahead.

It is the invention to lapped sheet conveyance. In fact, it will operate equally as eectively in conjunction with feeders which feed sheets in serial or non-lapped sequence, where sheets might be fed out of time, or feeders which feed either lapped or serially, just as long as gaps within a critical range control the bailiing of sheets as described. It is also to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

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

l. In combination with a conveyor for advancing sheets along a defined path, a sheet baiile, a sheet operated detector linger, and means whereby movement of the detector nger into or out of the defined path of sheet travel is transmitted to the sheet baiiie to move said baiiie respectively out of or into the-dened path of sheet travel.

2. In combination with a conveyor for advancing partially lapped sheets along a dened ,m path, a sheet baiile above the path of sheets including a surface arranged to rest on sheets passing therebeneath, a support for said baille which permits it to drop across the path of sheet advance in the absence of a sheet, and retaining 45 means to hold said baile across the dened path of sheet travel.

3. In combination with a conveyor for advancing partially lapped sheets along a dened path, a projection to raise a portion of the adm vancing sheets above said path, a sheet bame above the path of sheets including a surface arnot necessary to limit the application of i ranged to rest on sheets passing therebeneath, and a support for said baiiie which permits it to drop across the path of sheet advance adjacent said projection in the absence of a sheet.

4. In combination with a conveyor for advancing partially lapped sheets along a dened path, a sheet baiiie above the path of sheets including a surface arranged to rest on sheets passing therebeneath, a support for said baille which permits it to drop across the path of sheet advance in the absence of a sheet, a detector nger between said baille and the discharge end of the conveyor movable into and out of the path of sheets responsive to sheets passing therebeneath, and means on said detector iinger to prevent said baiile from dropping across the path of sheet advance when no sheet is under said detector finger.

5. In combination with a conveyor for advancing sheets along a defined path, a sheet bale and detector means responsive to the gap between successive sheets for operating the baiiie, said baffle and said detector spaced longitudinally along the path of sheet travel and defining a predetermined gap for controlling the operation of said baille.

6. In combination with a conveyor for advancing sheets along a defined path, a sheet baille and detector means responsive to the gap between successive sheets for operating the baille, said baille and said detector spaced longitudinally along and above the path of sheet travel and deiining a maximum predetermined gap for operating said baiiie down.

7. In combination with a conveyor for advancing sheets along a dened path, a sheet baille and detector means responsive to the gap between successive sheets for operating the baie, said baille and said detector spaced longitudinally along and above the path of sheet travel and dening a maximum predetermined gap for operating said baille down and a minimum predetermined gap for operating said baille up.

8. The method of conveying sheets in lapped formation from a pile to a machine, wherein relative motion between a leading sheet and the following sheets is produced during a registering operation, which comprises baiing the passage of sheets immediately following a gap in the lapped formation of the sheets.

DAVID P. SANFORD.

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