US2841391A - Sheet feeding mechanism - Google Patents

Description

July 1, 1958 R. K. NORTON SHEET FEEDING MECHANISM 2 Sheet s-Sheet 1 Filed April 7, 1954 INVENTOR. ROBERT K AORTO/V I. MW

y 1, 1958 R. K. NORTON SHEET FEEDING MECHANISM 2 Sheets-Sheet 2 Filed Apri l 7, 1954 INVENTOR. RGBERT K AURTO/V BY /3 I ATTOENEYS 2,8415%"1 Patented July 1, 1%58 easiest sneer Rename linens Robert K. Norton, 'fwinshurg, Ohio, assignor to Harrisintertype Corporation, a corporation of This invention relates to improvements in sheet feeding mechanism, particularly mechanism for feeding sheets one at a time from the top of a pile of sheets and over an endless conveyor to a printing press or the like.

One of the objects of the invention is the rrovision of a feeder of the character stated in which the forwarding device disposed above the top of the pile of sheets op crates at speeds varying from minimum to maximum, back again to minimum during each cycle, and in which the sheets are taken at the point of minimum speed.

Another object is the provision of a feeder of the character stated in which the sheets are transferred by the forwarding device to an endless conveyor which transports them to front guides and in which the endless conveyor partakes of changes in speed varying synchronously with the changes in speed of said sheet forwarder.

Still another object is the provision of a feeder of the character stated in which the forwarding device is a rotating vacuum wheel, and in which the distance between the front guides and the forward edge of the top sheet of the pile may be equal to the circumference of the said wheel or a multiple thereof, whereby the taking of one sheet by the sheet forwarder and the registering of a preceding sheet against the front guides may occur simultaneously.

A further object is the provision of means for adjusting the angular position of the vacuum wheel on its shaft, whereby the simultaneous action of the forwarding means and the registering of sheets may be maintained regardless of variations in the character of the stock being fed and regardless of wear in the mechanism.

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 diagrammatic side elevational view of a sheet feeder embodying the invention;

Fig. 2 is a fragmental sectional view taken substantially on the line 2-2 of Fig. 1 showing common means for driving synchronously at varying speeds the sheet forwarding means and the tape conveyor;

Fig. 3 is a fragmental top plan view taken substantially on the line 3-3 of Fig. 1;

Fig. 4 is a detail view on a larger scale partly in section on the line i-d of Fig, 2; and

Fig. 5 is a fragmental perspective view showing diagrammatically front guides at the forward end of a feed board and sheet grippers on an impression cylinder, at approximately the time when a sheet is being taken by the cylinder grippers.

Referring to Fig. 1, i represents a pile of sheets supported upon a pile board 11 which is adapted to be raised an increment at a time by lifting chains 12 in a manner well-known in the art. A flat plate 13 is supported a slight distance above the top of the pile by brackets 14 carried upon transverse bars 15 supported in the frame of the machine. Plate 13 is slotted to receive the lower periphery of a vacuum wheel 16 which is of more or less conventional form. The wheel is mounted upon a transverse shaft 17 with a bushing 18 interposed in order that the wheel may have a limited angular adjustment upon the shaft. This adjustment is accomplished by mounting a pin 2% in a hole in the wheel, the pin also extending through a slot 21 in an arm 22 mounted upon the shaft and held against rotation thereupon by a key 23 which is adapted to slide in a keyway in the shaft. The pin 29 has an integral collar 24 adapted to engage one surface of the arm 22. in the opposite surface a washer 25 is inset and a nut 21 is threaded on the pin so that when the nut is drawn up tight the arm is firmly gripped between the washer and the collar 2d. As will be obvious the vacuum wheel may be angularly adjusted by loosening the nut 26, turning th wheel to the desired position and retightening the nut. if it becomes desirable to move the wheel lengthwise of the shaft that may be done by loosening a setscrew 27 when the wheel with its arm 22 may he slid along the shaft to the desired point and the setscrew 27 then again tightened. Washer 25 has a pointed outer end which cooperates with a scale 29 on the rim of the wheel 16, which serves as an indicator to show that the wheel has been adjusted from its normal position angularly in either direction. A sp 3t) interposed between the arm 22 and the wheel 16 urg s the wheel against a leather washer 28 communicating x a vacuum line. The washer 23 acts as a seal against the adjacent side of the wheel 15. Wear in the washer will be compensated for by the spring 39.

In the wheel to there are a series lateral holes 31 which communicate with radial openings 32. As the wheel rotates the holes 31 are adapted to register one after another with a port 3 in the washer 28 and fitting 34. The fitting 34 is mounted upon a bracket 35 carried by one of the bars and receives one end of a. flexible conductor which extends to a source of vacuum. When the wheel 15 reaches the position of rotation illustrated in Fig. l, the first hole 31 re, with the port 33 and suction becomes effective t and grip the uppermost sheet the pile. As the vxneel rotates clockwise, as viewed in Fig. l, vacuum is applied to subsequent holes 3?. to grip the sheet. The grip of the wheel on the sheet continues and moves it forward until a lateral groove 37 comes into register with the port 33, whereupon the suction is broken. By that time however the forward edge of the sheet has reached the bight between gravity rollers 38 and roller 40 over which run the tapes 3? of an endless conveyor. Gravity rollers 33 are journaled in the rear ends of arms d]; which are oscillatably mounted on a transverse rod fixed in the frame. The upper runs of tapes travel over a feed board 43 and thence around an idler roller 3 2.

Forwa l' beyond the tapes there is a feed board extension a the forward end of which there are front guides with sheet grippers 48 that take each sheet as it en"= the press, the remaining portions of which are not I lustrated.

The drive for the sheet forwarding wheel is; and endless conveyor is substantially as follows.

At one end of impression cylinder 47 there is a. g 5% the pitch circle of which has the same diameter as the circumference of the cylinder. A train of gears, such as 51 and 52, carry the drive from gear 59 to a gear 53 which is journaled upon a stub shaft 54 that is fixed in a frame bracket 55. in a laterally projecting part of gear 53 there is a radial slot 56. A gear 57 which is preferably of the same diameter as gear 53, and consequently of the same. diameter as gear 56, with its axis parallel to. but slightly offset from the axis of gear 53,

.is rotatably mounted on a stub shaft 58 that is fixed in one of the frame members 59 of the machine.

Gear 57 is driven at varying speeds by means of a roller 66 mounted on a pin that is fixed in the gear, the roller running in slot 56 of gear 53. This form of drive results in a constantly varying motion of gear 57 from minimum speed up to maximum speed and back again to minimum speed during each revolution of constant speed gear 53; At the position shown in the drawings the rotation of gear 57 is at its minimum speed point. Since at this point the roller 60 is spaced materially from the axis of shaft 54, the minimum speed of shaft 58 is obviously greater than zero. V

A sprocket wheel 61 is fastened to one side of gear 5 7, and over'this sprocket wheel and a sprocket wheel upon which the roller 40 is mounted, the pitch circle of.

gear 64 being the same as the circumference of the roller. Consequently the circumferential speed of'the pitch circle of gear 57 and the surface speed of roller 40 are the same, and since the circumference of the vacuum wheel 16 turns at the same speed as the'pitch circle of gear 57, the surface speed of the conveyor and of the vacuum wheel are the same. The wheel 16 and tapes 39 are driven at a speed greater than press speed for a short time in each cycle to make up for the period during which their speed is reduced.

A plurality'of nozzles 66 disposed beneath wheel 16 transmit a blast of air against the underside of plate 13. A suction is therefore created'between the plateand the top'of the pile which tends to lift the top sheet against the plate. The nozzles 66 then assist in flufling the upermost sheets of the pile. The wheel grips the sheet at approximately its minimum speed, which is materially lower than maximum speed. The suction grip of the wheel upon the sheet is therefore readily effected. As the wheel accelerates the sheet is drawn off under the plate 13, the air blastserving to float the'sheet, or at least the middle portion thereof, and thus facilitating its movement. The sheet is to be advanced into the grip eifectedby roller 40 and rollers 38 while traveling at the same speed as roller 40 and is to be taken onto the endlessconveyor tapes 39 and fed forward toward the press. Shortly after the forward edge of the sheet begins its travel on the conveyor the groove 37 in the vacuum wheel exhausts the suction to the atmosphere and the sheet is then under the control of the conveyor exclusively. Gravity wheels 68 and 69 disposed above the tapes 39 insure'good traction of the tapes upon the sheet. As shown,'the distance between the front guides 46 and the forward edge of the top sheetof the pile is the same as the circumference of wheel 16. Consequently at the time the wheel takes invention sheet S should reach the registering point too early in the cycle, it might pass the front guides before they would move .into position to stop the sheet. On

the contrary if the sheet should reach the front registering.

'the front edge of one sheet S the preceding sheet S point too late, sheet detecting mechanism operable when.

nosheet is present would actuate conventional throwoff mechanism to trip the cylinders of the press to impression off position. The present invention provides an adjustment of a very simple character which insures the arrival of the sheet S at the registering point at precisely the right moment. 7 The driving mechanism is not in any. way affected or changed, and the synchronized relationship between the vacuum wheel and the conveyor is not disturbed whenever an adjustment is made tore-time the advance of sheets to the front stops. 7

Although in the present disclosure the distance between the front guides and the forward edge of the top sheet of the pile is the same as the circumference of the vacuum wheel, it should be understood that this distance may be a multiple of such circumference;

Having thus described my invention, I claim: m

1. In a sheet feeder, a rotary vacuum wheel sheet forwarding device, an endless conveyor device adapted to receive sheets from said forwarding device, front guides against which the sheets are registered by said conveyor,

means for driving said devices synchronously at speeds varying from a minimum speed above zero to maximum and back to minimum duringv each cycle, the taking of a sheet by said forwarding device and the registration of a preceding sheet againstsaid front guides occurring at about said minimum speed. i e

2. In a sheet feeder, a rotary vacuum wheel sheet forwarding device, an endless conveyor device adapted to rceive sheets from said forwarding device, front guides against which the sheets are registered by said conveyor device, ashaft by which the forwarding device is op erated, a shaft by which the conveyor device is driven, means for driving said shafts synchronously at varying speeds during each cycle, and means for adjusting said sheet forwarding device relatively'to its shaft.

3. A sheet feeder substantially as defined in 'claim 2,

wherein the means for driving said shafts comprises a common rotating element the speed of which varies from a minimum speed above zero to maximum and back again to minimum during each cycle. i

4. A sheet feeder substantially as defined claiin l,

wherein the means for driving said devices comprises a common rotating element the speed of which varies from minimum to maximum and back again to duting each cycle, and means for making effective suction in" said vacuum wheel for a short interval while the wheel' is rotating at about minimum speed. v

5; A sheet feeder substantially as defined in. claim 2, wherein the means for driving said shafts comprises a common rotating element the speed of which varies from a minimum to maximum and back again to am; ing each cyclefmeans for making effective suction fin said vacuum wheel for a short interval while said wh eelf.

is rotated at about'minimum speed, and wherein said adjusting means comprises means for-lockingsaidvac-Q; uum wheel in various angular positions upon itsshaft, whereby any' slippage of sheets on said wh e'el may be" compensated for by said adjusting means and the simultaneous taking of a sheet by the wheel and registering of: a preceding sheet against the front guides may bem aintained regardless of the character of stock being fedl'l 6. In mechanism of the character described, a printing cylinder, an endless conveyor adapted to'carry sheets forward to said cylinder, front guides at the point'of transfer from said conveyor to said cylinder, a sheet forwarder comprising a vacuum wheel disposed above a pile of sheets and adapted to take sheets one at a time from said pile and transfer them to said conveyor, the distance between the said front guides and theforward edge of the top sheet of the pile being equal to or a multiple of the circumference of said wheel, and means for adjusting said vacuum wheel .angularly upon its shaft to compensate" for differences in the character of the stock being fed. ,7 V

7. In mechanism of the character -described,a'vacuun'1 wheel sheet forwarder disposed above a pile of sheets, a feed board disposed forward of said vacuum' wheel, an

endless conveyor running over said feed board, pull-out rolls disposed at the rear end of. said endless'conveyor,

a shaft driven at constant speed, a rotating element turn ing about an'axis parallel to said driven shaft, said elementoperatively connected to said driven shaft to turn at a variable speed from minimum to maximum and back again to minimum during each cycle, said element having one driving connection with said pull-out rolls and another driving connection with said vacuum wheel to impart the same surface speed to said vacuum wheel and said pull-out rolls, and means for adjusting said vacuum wheel angularly.

8. A sheet feeder substantially as defined in claim 1, including means for making efiective suction in said vacuum wheel for a short interval while said wheel is rotating at about minimum speed, and means for advancing or retarding the application of said vacuum to compensate for relative slippage between said sheets and said wheel.

9. A sheet feeder substantially as defined in claim 8,

wherein said means for advancing or retarding the applicatlon of vacuum comprises means for adjusting said vacuum wheel angularly about its shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,157,849 Danielsson Q. May 9, 1939 2,159,147 Gumbel May 23, 1939 2,220,073 Belcher et a1. Nov. 5, 1940 2,227,370 Seybold Dec. 31, 1940 2,231,339 Krueger Feb. 11, 1941 2,313,100 Stevens Mar. 9, 1943

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