US2876006A - Sheet feeding device for rotary duplicating and the like machines - Google Patents

Description

March 3, 1959- 1. V. BENHAM 2,

SHEET FEEDING DEVICES FOR ROTARY DUPLICATING AND THE LIKE MACHINES Filed May 16. 1955 s She et's -Sheet 1 /////////////////////////I///I/;llll///////////l March 3, 1959 L. v. BENHAM 2,876,096

Y SHEET FEEDING DEVICES FOR ROTARY DUPLICATING AND THE LIKE MACHINES Filed May 16. 1955 3 Sheets-Sheet 2 March 3, 1959 L. v. BENHAM 3 3 SHEET FEEDING DEVICES FOR ROTARY DUPLICATING AND THE; LIKE MACHINES Filed May 16. 1955 5 sheet -sheet 3 SHEET FEEDING DEVICES FOR ROTARY DUPLI- CATING AND THELIKE MACHINES Leonard Victor Benham, West Croydon, England, assignor to Block & Anderson, London, England, a British company Application May 16, 1955, SerialNo. 508,707

Claims priority, application Great Britain June 1,1954.

3 Claims. (Cl. 271-66) The invention relates to sheet feeding devices for rotary duplicating and the like machines and is applicable particularly but not exclusively to such machines wherein copy sheets moistened with a volatile solvent are fed between a printing couple consisting of a drum, to the periphery of which is secured a hectographic master sheet, and a co-operating counter pressure roller.

To avoid the labour of handfeeding, various automatic sheet feeding devices have been proposed for such machines. For example, it is known to feed copy sheets from a stack by means of a friction feed roller resting upon the top sheet of the stack and intermittently driven from the drum by gearing which includes a one-way clutch such as a free-wheel device. Various modifications of such a friction feed arrangement have been adopted in the past and although the one-way clutch device has been incorporated at various different points in the transmission it has not been found possible to dispense entirely with a one-way clutch device for obtaining the required intermittent drive without at the same time introducing undesirable inertia effects in the moving parts.

An object of the present invention is to provide" a fric-' tional feed device which although effecting the desired separate feeding of sheets from a stack, is itself positively driven, thereby avoiding the complication and expense of one-way clutch devices.

According to the present invention an automatic sheet feeding device in printing, duplicating and the like machines for feeding sheets singly to a printing position comprises a rotary feeding'member having a cylindrical feeding surface making contact with the sheets and comprisingtwo segments one of which is a frictionalfeeding surface and the other of which is substantially a nonfrictional surface, and means forpositively rotating saidfeeding member whilst in contact with the sheet.

According to a further aspect of the invention sheet feeding means in printing duplicating and the like machines for feeding sheets singly from a stack to-a rotary printing couple comprises a first sheet feeding means comprising a roller having a cylindrical surface, an arcuate segment of which has a frictional feeding surface and an other segment of which has a substantially non-frictional surface, means for positively rotating said roller in timed relation with the printing couple whilst resting on the stack, and a second sheet feeding means positioned between the said roller and the printing'or duplicating drum and comprising a pair of feed rollers one of which is intermittently driven in timed relation with the drum.

According to a further aspect of the invention, sheet feeding mean for feeding sheets singly from a stack to a rotary printing couple comprises two sheet feeding devices in tandem the first. of'which is a rotary feeding member having a cylindrical surface comprising a frictional feed segment extending over an arcuate portion of said surface and designed to feed said sheets when rotated in contacttherewith and a substantially non-frictional'segmenti extending over a. different are of said surface anddesigned to produce slipping. between said: segrdevices is a pair of rollers positioned between "the first feeding device and the printing couple, said first feeding mentand the sheet, and the second of which feeding device being positively driven in timed relation with the printing couple, and said second feeding device being intermittently driven in timed relation to the printing couple to pick up single sheets fed forward by'said first feeding device at a point not before'said first feeding device has finished its positive feed stroke.

Preferably the segmented feeding roller is positively' driven from the printing. drum by a 1:1 ratio gear so that'one complete feeding cycle is performed for each 1 extending for example over an -arcuate distance of'rather complete printing cycle; also the circumference of the feed roller and the length of the frictional feed segmentare chosen to suit the distance to' be travelled-by the copy sheetbefore being picked up by the second pair of rollers.

Means are also provided for retaining and stabilizing the stack of copy sheets centrally of the feed'lineand to ensure that only one sheet is fed at each stroke and that the dragproduced by the smooth segment of the segmented roller is insufficient to detach the'sheet from the stack.

A fuller description of; a sheet feeding device according to the invention will now be given as applied to a rotary duplicating machine of the type shown in'the accompanying drawings in which:

Fig. l is a view looking towards the inside of the lefthand side frame of the machine with the majority of the parts shown in cross-section for clearness;

Fig, 2 is an elevation looking at the outside of the lefthand side frame and Y i i Fig. 3 is a plan, partly in section, showing how the drive is transmitted to the friction feed rollers.

Referring now to the drawings, the machine has a printing couple comprising a printing drum 1 and acounter pressure roller 2, which printing drum carries a printing master (not shown) secured to the periphery thereof by means of a clip 3. The'copy sheets are fed singly from a stack 4 by means of two sheet feeding devices positioned in tandem between the feed table 5 carrying the copy sheets and the printing couple.

The first sheet feeding device comprises a pair 'of friction feed rollers 6, 7. These rollers are each keyed on a driven shaft 8 which passes through an enclosed gear case 9 which is arranged to be pivotable bodily about a counter shaft 10 extending across the front of the ma chine, and means are provided, indicated generally by reference 11 (Fig. 2), for automatically holding the said pair of feed rollers in the raised or inoperative position when automatic sheet feeding is not being performed.

The pair of feed rollers 6, 7 are positively driven in timed relation with the printing drum by means of a gearing such that one sheet feeding operation will be per-' formed for each complete revolution of the drum. As shown, the gearing arrangement for achieving this corn prises a chainllconnecting a sprocket 13 on the drum shaft and sprocket 14 on the near end of the countershaft 10, from which a further chain 15 and sprockets 1'6 and 17 enclosed in the gear case transmit the drive to: the common shaft 8. The gearing here described in this Each of the feed rollers has a cylindrical surface which is divided into two segments, and one of said segments consists of a frictional feeding surface provided for example by a strip19 of corrugated rubber or the like material suitablysecured to the periphery of the roller and Patented Mar. 3, 19 59 sheet to the printing couple.

- 3 more than 120.

2 0 of the feed roller is designed to have a minimum frictional effect for slipping over the surface of the copy sheets and may consist for example of a highly polished metal.

The said pair of feed rollers in their normal position,

rest upon the top sheet of the stack 4 of copy sheets which are stabilized and aligned in the line of feed by means of a feed table provided with a pair of laterally adjustable paper guides 21 and 22 having removable friction pads 23,fitted on the inside surface thereof to grip the sides of the stack of sheets so that only one sheet at a time is detached and fed from the stack.

The second sheet feeding device is arranged between the first feeding device and the printing couple and comprisesa pair of rollers 30, 31 suitably journalled in bearingscarried in the side frames of the machine at a suitable distance in front of the printing couple. The lower roller 30 is mounted for idle rotation and the upper roller 31 is arranged to be driven intermittently .in timed relation with the printing drum as will be further described.

In the type of machine here described the upper roller also serves as. a moistening roller for applying a liquid solvent for hectographic ink to the upper face of each copy sheet passing through the feed rollers. The means for applying the liquid solvent include a moistening pad 28 resting against the roller 31 and supplied by suitable means, e. g. a pump, with a hectographic ink solvent. The

' is secured one end of a connecting rod 40 mounted to reciprocate at each revolution of the drum. For this purpose the connecting rod is slotted to move upon a guide pin 41 carried upon an adjustable bracket 42. The connecting rod is coupled to a toothed sector 43, pivoted at 44 in the side frame of the machine, by means of an adjustable pin and slot coupling, and the toothed sector is permanently in engagement with a pinion 47 which is coupled to the shaft of the upper one 31 of the two rollers through a one-way clutch for example a free-wheel device so that the said upper roller is positively rotated in the feeding direction shown by the arrow by a forward stroke of the toothed sector whilst the idle stroke of the toothed sector in the opposite direction serves only to reverse the pinion 47.

. It will be understood that the function of the friction feed rollers 6, 7 is to present the copy sheet to the line of contact of the feed rollers 30, 31 and that these latter rollers must have finished any motion connected with the feeding of the preceding sheet before receiving the next sheet from the rollers 6, 7.

The arrangement and operation of the machine is as follows: By known means printing pressure is taken off the printing couple in the initial stage of feeding the first In the position shown in the right-hand elevation in Fig. l, the friction feed roller 6 has been driven counter-clockwise through the chain and sprocket drive above referred to and'the top sheet of the stack has been positively fed by contact of the frictional feeding segment, it being .understood that the frictional pressure of the pads on the paper guides is sutlicient to stabilize and centre the stack of sheets but not sufficient to prevent the sheets being drawn from the top of the stack in succession. The arc length of the frictional feeding segment 19 ofthe feed roller is very slightly, greater than that. required to feed the sheet to the line of contact of The remainder of the cylindrical surface s the second pair of feeding rollers 30, 31. Thisslight excess length of the segment 19 is effective in the final stage of this feeding motionto cause a slight bulge in the copy sheet the advanced portion of which now extends, as shown in the drawing,.between the bight between the second set offeed rollers and the tangent point of feed the sprockets may be adjustable.

roller 6. The drum isnow in the registration position and the toothed sector 43 is'stationary. Printing pressure is now applied to the counter-pressure roller. Upon further rotation of the hand crank the second pair of feed rollers 30, 31 now take up the feeding of the sheet to the printing couple. The toothed sector 43 swings on its feed stroke to rotate the moistening roller 31 in the feed direction whereby the sheet is now pulled from the stack whilst the tail end of the sheet now slips between the still rotating non-frictional segment 20 of the feed roller 6 and the remaining sheets of the stack. Due to this slipping Y of the feed roller 6 the copy sheet remains taut between the two feeding devices.

The completion of the feed stroke of sector 43 is timed to present the copy sheet to the line of contact of the printing couple in proper register with the master sheet, whereafter the printing couple pulls the copy sheet through the rollers 30, 31 which are allowed to rotate by overrunning the free wheel device whilst the sector 43 returns. If a full length sheet is used, which usually takes up nearly the whole of the drum circumference, the moistening roller 31 will still be rotated by the traction of the sheet for some time after sector 43 has returned. The parts are so designed and timed with respect to each other that with the maximum length of copy sheet, the moistening roller 31 is stationary before the second sheet comes into the position formerly occupied by the first sheet. Consequently the feed stroke of the friction segment 19 can only take place towards the end of the drum cycle.

However, sheets of varying length may be copied, the

minimum length being greater than the spacing between the two feeding devices and greater than the spacing between the feed rollers 30, 31 and the printing couple.

Accurate register of the copy sheet and master during printing is obtained by the adjusting device 42 above referred to which varies the relative position of the pin 45 and slot 46 so as to vary the speed and length of the feed stroke of sector 43.

The benefits of the invention may be obtained in machines other than that described, for example the feeding device might be used for feeding direct to a printing couple without intermediate feed rollers such as 30, 31.

In order to allow accurate adjustment of the timing of the drive from the drum shaft to the feed rollers 6, 7, e. g. by an angle less than one sprocket tooth, one of For example sprocket 13 may be secured on the drum shaft by means of a mounting plate which is itself angularly adjustable by means of arcuate slots which accommodate locking screws. The arrangement for allowing the gear case to be swung upwards into the position shown in Fig. 2 does not disturb the timing of the drive because, as may be seen from Fig. 1, the chain 15 can move round both sprockets 16 and 17 as the gear case is raised, and the original relationship is restored when the gear case is lowered again.

Means may be provided to control the pressure of the feed rollers 6 and 7 on the stack. In the example shown in the drawing the gear casing is supported on a sleeve 24 and a torsion spring adjustment device 25 allows the pressure to be varied.

I claim:

1. In a printing, duplicating or like machine having a printing couple comprising a rotatable printing drum and a co-operating counterpressure roller, automatic sheet feeding means comprising a horizontal sheet supporting table having stack aligning means for laterally aligning a stack of copy sheets thereon, a first sheet feeding device comprising a horizontal pick-off roller rotatably mounted in a swinging frame which is loosely pivoted upon a fixed position countershaft whereby said pick-off roller rests by gravity upon the top sheet of a stack of copy sheets on said table, said pick-01f roller having a first friction surfaced feed segment embracing part of its periphery and adapted to grip and feed the top copy sheet from said stack and a second non-frictional surfaced feed segment embracing the remainder of its peripheral surface and adapted to slip on said top copy sheet and a first chain and sprocket driving connection between said pick-off roller and said countershaft and a second chain and sprocket driving connection between said countershaft and said printing drum, said driving connections having an overall transmission ratio of one-toone whereby said pick-off roller moves in fixed and equiangular relationship to said printing drum during each operative revolution of the latter, a second sheet feeding device comprising a pair of contacting and aligned rollers mounted in fixed position parallel to and in between said printing drum and said pick-off roller, actuating means interconnecting said pair of sheet feeding rollers to said printing drum for causing rotation of said pair of sheet feeding rollers in a sheet feeding direction during a part only of each operative revolution of said printing drum, said actuating means being arranged to commence the rotation of said pair of sheet feeding rollers at an instant which is subsequent to that at which said first frictional surfaced feed segment of said pick-off roller has passed out of contact with said top copy sheet during each operative revolution of said printing drum.

2. In a hectographic spirit duplicating machine having a printing couple comprising a one-revolution printing drum having master copy holding means and a co-operating counterpressure roller, automatic sheet feeding means comprising a fixed position horizontal sheet supporting table having stack aligning means for laterally aligning a stack of copy sheets thereon, a first sheet feeding device comprising a pair of spaced apart pick-off rollers secured to a horizontal shaft rotatably mounted in swinging support means so as to rest under gravity upon the top sheet of said stack of copy sheets on said table, said swinging support means being freely pivoted upon a fixed position countershaft, said pick-01f rollers each having an initially operative friction surfaced feed segment embracing part of its periphery and adapted to grip and feed the top copy sheet from said stack and a non-frictional surfaced feed segment embracing the remainder of its periphery and adapted to slip on said top copy sheet, a first positive drive connection between said horizontal shaft and said countershaft and a second positive drive connection between said countershaft and said printing drum whereby a positive drive transmission having a one-to-one transmission ratio is provided between said printing drum and said pick-01f rollers for causing continuous equi-angular rotational movement in a forward sheet feeding direction of said pick-01f rollers during each operative revolution of said printing drum, a second sheet feeding device comprising a pair of contacting and aligned rollers mounted in fixed position parallel to and in between said printing drum and said pick-off roller, spirit moistening means operative to moisten the surface of one of said pair of rollers, actuating means interconnecting said pair of sheet feeding rollers to said printnig drum for causing intermittent rotation of said rollers in unison during a part only of each operative revolution of said printing drum, said actuating means being arranged to commence the rotation of said pair of feeding rollers at an instant-which is subsequent to that at which said frictional surfaced feed segment of said pick-off rollers have passed out of contact with said top copy sheet during each operative revolution of said printing drum.

3. In a printing, duplicating or the like machine having a printing couple comprising a printing drum and a counterpressure roller, automatic sheet feeding means comprising a sheet feeding table having means for laterally aligning a stack of copy sheets, a pick-off roller pivotally mounted for bodily movement about the fixed axis of a countershaft arranged parallel to the axis of the printing drum so as to bear upon the stack and to descend as the thickness of the stack is decreased, said pick-off roller having a frictional feeding segment adapted to grip and feed a copy sheet from the stack and a nonfrictional feeding segment adapted to slip on the copy sheets, and means for positively and continuously driving said pick-off roller from said printing drum through the intermediary of said countershaft, said driving means comprising a driving shaft coaxial with and secured to the printing drum and a driven shaft upon which said pick-off roller is mounted, first sprocket and chain gearing between said driving shaft and said countershaft and second sprocket and chain gearing between said countershaft and said driven shaft, said first and second sprocket and chain gearing providing an overall positive drive between said driving shaft and said driven shaft having a 1:1 drive ratio.

References Cited in the file of this patent UNITED STATES PATENTS 1,991,989 Trompier Feb. 19, 1935 2,220,264 Morrison Nov. 5, 1940 2,269,571 Aktabowski Jan. 13, 1942 2,642,786 Gilchrist June 23, 1953 2,661,686 Levin Dec. 8, 1953 2,679,801 Ford June 1, 1954

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