US2974952A

US2974952A - Registering mechanism for the accurate feed of sheets of paper to a printing device, particularly to duplicating machines

Info

Publication number: US2974952A
Application number: US664618A
Authority: US
Inventors: Zeuthen Karl Gustav
Original assignee: Zeuthen and Aagaard AS
Current assignee: Zeuthen and Aagaard AS
Priority date: 1956-06-19
Filing date: 1957-06-10
Publication date: 1961-03-14
Anticipated expiration: 1978-03-14

Description

March 14, 1961 K. G. ZEUTHEN 2,974,952

REGISTERING MECHANISM FOR THE ACCURATE FEED 0F SHEETS OF PAPER TO A PRINTING DEVICE PARTICULARLY T0 DUPLICATING MACHINES Filed June 10, 1957 H91 Fi 4 a 2 fi I? "2 ,L. A I MLMAM ML MZW of the printing device.

, 2,974,952 p Patented Mar- REGISTERING MECHANISM FOR THE ACCURATE FEED OF SHEETS OF PAPER TO A PRINTING DEVICE, PARTICULARLY T DUPLICATING MACHINES Karl Gustav Zeuthen, Gentofte, Denmark, assignor to Zeuthen & Aagaard A/S, Copenhagen, Denmark .Filed June 10, 1957, Ser. No. 664,618

' Claims priority, application Netherlands June 19, 1956 4 Claims. (Cl. 211-53 The invention relates to a registering mechanism for the accurate feed of sheets of paper to a printing device,

particularly to duplicating machines, and provided with at least one paper feed roll rotatable around a fixed axis.

The object of the invention is to provide a registering mechanism which in a simple way ensures that each sheet of paper is fed to the printing device with such a degree of accuracy that the print will every time be placed accurately on the paper. This may for example be of importance in the case that before or after being provided with the printed text the sheets of paper are to be provided with illustrations in another machine.

According to the invention, the accurate registering is obtained by a registering mechanism provided with at least one pair of associated counterpressure or backpressure rolls for each paper feed roll, the said backpressure rolls being mounted movably in relation to each other and to the feed roll in such a way that the backpressure roll, the registering roll, located nearest the printing device will first get into contact with the arrested feed roll for the formation of a registering stop for the front edge of a sheet of paper advanced to this stop, and that next the other backpressure roll will get into contact with the feed roll with the sheet of paper as intermediate layer, while the feed roll is arranged for hereupon performing a feed motion synchronized with the motion feeding of the sheet along a line well behind the edge :of the sheet. a

The invention is described in detail with'reference to the accompanying purely diagrammatical drawing in which a 1 Figs. 1-4 illustrate four phases of the feed of the paper, and i e Fig. an embodiment of the operating mechanism for the two backpressure rolls. Y a In Figs. 1-4, 1 designates a feed roll, and 2 and 3 two .backpressure rolls movable in against and away from the feed roll, and the former of which acts as registering roll, while the latter acts as backpressure roll proper which together with the feed roll starts the feed of the paper after the accurate registering has been performed.

In Fig. 1, the backpressure roll 2 is in contact with the arrested feed roll 1, and a sheet of paper 4, which from the left towards the right in the figure is advanced =along-guiding means,-not shown, will contact" the backpressure roll 2 serving as registering roll along the line where the latter rests against the feed roll 1. Hereby the line, along which the front edge of a sheet of paper is stopped when by transport means known per se and not shown the sheet is advanced across the feed roll, is accurately defined and invariable from one sheet of paper to the succeeding sheet. The location of the sheet of paper in relation to the printing device, e.g. in rela- The arrangement according to the invention ensures a non-slidable initial gripping and tion to a stencil, is therefore, when the starting line has thus been accurately fixed, determined solely'bythe time for the start of the feed and the velocity at which the feed is performed. This also means that, as will be mentioned in the following, there is a possibility of performing 'a regulation by one or both of the said two factors being regulated.

In Fig. 2 the backpressure roll 3 has, viewed in relation to the position shown in Fig. 1, moved downwards in the direction towards the feed roll 1, and as the backpressure roll 3 in relation to the registering roll 2 is located at the rear 'viewed in the direction of feed of the sheets of paper, which direction is towards the right in the figure, the backpressure roll 3 will press the sheet of paper 4 firmly against the feed roll 1. The registering mechanism is hereby ready for feeding the sheet of paper to the printing device not shown in these figures. Since the sheet is gripped at a distance from the edge there is no risk that slip will occur at the moment when feeding is initiated.

In Fig. 3, the feed roll 1 has started its rotary clockwise motion. Guides, not shown, ensure that the sheet of paper advanced is led to the printing device where the printing rollers or a corresponding mechanism of the latter catch hold of it.

Fig. 4 shows the position of the feed roll 1 of the registering mechanism and the two backpressure rolls 2 and 3 after the feed mechanism of the printing d'evice has caught hold of the sheet of paper and taken over the advance of the latter. The backpressure rolls 2 and 3 are both raised clear of the feed roll 1, so that the sheet of paper 4can be advanced freely. The feed roll 1, which in the example here shown is spring-actuated, moves in the opposite direction, viz. anticlockwise, back to a certain starting position which may be adjustable with a view to adjusting the location of the form or stencil with text in relation to an advanced sheet of paper.

In Fig. 5, an example is shown of the manner in which the two backpressure rolls 2 and 3 may be mounted. The backpressure rolls are at one end carried by a

bell crank

5, 6. The backpressure roll 2 can rotate around a movable shaft 7 which substantially radially in relation to the feed roll 1 is displaceable in a slot 9 at the end of the arm 6 of the bell crank. The shaft 7 is actu-.

'ated towards the feed roll 1 by a spring 10. The backthe feed roll 1, the shaft 7 of the backpressure roll 2 being displaced in relation to the arm 6 of the bell crank when the said arm, after the backpressure roller 2 has got into contact with the feed roll 1, is moved further in the direction in towards the feed roll 1.

At the free end of its arm 5, the

bell crank

5, 6 is provided with a roll 12 which is rotatable around a fixed axis and rests against a cam disc 13, the motion of Y which in a duplicating machine is synchronized with the motion of the stencil.

The two

arms

5 and 6 of the hell crank may. be resiliently interconnected, so that a motion of the roll .12 and the arm 5 will not entail a motion of the arm 6 and thereby of the backpressure roll 2, if the rolls 221561 3 are both in contact with the feed roll, but on the other hand ensure that a suitable pressure is provided between the rolls to prevent the paper from slipping between the rolls.

When in this connection reference is made to rolls, e.g. feed roll and backpressure roll, the latter need only be very short rolls, e.g. about 1-2 cm. in the axial direction. Several sets of rolls may then be used, e.g. one

set at either side of the sheet of paper to be advanced and, if necessary, a set at the middle. The feed roll 1 may be a through roller, while the backpressure rolls may be designed as rolls that are rather short in the axial direction.

The feed roll 1 may in any suitable way be in connection with the main shaft of the printing device. As an example may be mentioned that on the shaft of the feed roll 1 a gear wheel may be secured which engages a toothed segment carried by one arm of a lever, the other arm of which carries a roll which is in contact with a cam disc moved by the main shaft of the machine. The toothed segment actuates the feed roll in the direction of advance, e.g. once for every revolution of a stencil in a duplicating machine. For the purpose of returning the feed roll there may around the shaft of the latter be placed a spiral spring which internally is secured to the shaft and externally to the frame of the machine, and which can be tightened when the toothed segment advances the feed roll. The feed velocity is determined by the shape of the curve disc, provided that the shaft of the machine is driven at a constant rate of revolution. It may be desirable to arrange it so that the feed roll is started slowly and gradually accelerated to the maximum velocity.

On the feed roll 1 or on the shaft of the latter or possibly on a mechanism coupled to the latter a cam or a similar member may be provided which abuts on an adjustment stop member which determines the starting position of the feed roll, ie the position it takes up at the moment when the registering roll 2 gets into contact with it. By making the adjustment stop member rotatable or displaceable it becomes possible to advance or retard the time at which the feed roll starts its feed motion, and thereby the possibility is obtained of adjusting the paper in relation to the stencil or the form, so that the latter is printed higher up or farther down on the paper dependent on the adjustment made.

The curve, according to which the feed velocity of the paper is varied, is conveniently so arranged that velocity is constant already a little before the termination of the feed motion of the paper, so that the front edge of the paper will always reach the printing rollers of the duplicating machine at the same velocity, viz. a velocity substantially corresponding to that at which the printing rollers are already running. Hereby is prevented that an adjustment of the registering entails a variation of the velocity at which the front edge of the sheet of paper arrives at the printing rollers.

The invention is not limited to the embodiment of the mechanism described, it being possible to vary details without deviating from the inventive idea. Thus may be mentioned that the rolls may be provided with a surface covering of a frictional material, such as rubber, and that guide plates or similar members known per se may be provided which guide the sheets of paper vertically and laterally. The invention may for example be used in connection with duplicating machines known per se.

I claim:

1. A registering mechanism for the accurate feeding of sheets of paper to a printing device, comprising at least one paper feed roll rotatable intermittently in opposite directions about a fixed axis and arranged for performing a feed motion synchronized with the motion of the printing device; a lever, means pivotally mounting said lever for movement towards and away from said paper feed roll and in a plane generally normal to said axis, a pair of idler backpressure rolls carried by said lever and spaced longitudinally thereof, said back pressure rolls including a feed-registering roll and a feed backpressure roll, said feed-registering roll being disposed in advance of said feed backpressure roll in the direction of paper feed, means carried by said lever normally mounting said feed-registering roll in a position closer to said feed roll for engagement with said feed roll in advance of contact of said feed backpressure roll with said feed roll and for movement relative to said lever away from said feed roll whereby said feed-registering roll and said feed backpressure roll may simultaneous- ]y engage said feed roll to feed a sheet of paper when said feed roll rotates, and means for pivoting said lever in timed relation with the rotation of said feed roll to first engage said feed-registering roll with said feed roll when said feed roll is stopped for cooperation with said feed roll to form a paper sheet stop and then to engage said feed backpressure roll with a sheet of paper stopped by said feed registering roll and clamp the sheet of paper against said feed roll for feeding the sheet of paper when said feed roll rotates.

2. The registering mechanism of claim 1 wherein said lever is in the form of a bell crank and said lever pivoting means includes a cam and a cam follower on said bell crank engaging said cam.

3. The registering mechanism of claim 2 wherein said bell crank is sectional and the sections have a resilient connection whereby the stroke of said cam may be in excess of that required to engage said backpressure rolls with said feed roll to assure the required engagement of said backpressure rolls with said feed roll.

4. A registering mechanism for the accurate feeding of sheets of paper to a printing device, comprising at least one paper feed roll rotatable intermittently in opposite directions about a fixed axis and arranged for performing a feed motion synchronized with the motion of the printing device; a lever means, means pivotally mounting said lever means for movement towards and away from said paper feed roll and in a plane generally normal to said axis, a pair of idler backpressure rolls carried by said lever means and spaced longitudinally thereof, said backpressure rolls including a feed-registering roll and a feed backpressure roll, said feed-registering roll being disposed in advance of said feed backpressure roll in the direction of paper feed, means carried by said lever means normally mounting said feedregistering roll in a position closer to said feed roll for engagement with said feed roll in advance of contact of said feed backpressure roll with said feed roll and for movement relative to said lever means away from said feed roll whereby said feed-registering roll and said feed backpressure roll may simultaneously engage said feed roll to feed a sheet of paper when said feed roll rotates, and means for pivoting said lever means in timed relation with the rotation of said feed roll to first engage said feed-registering roll with said feed roll when said feed roll is stopped for cooperation with said feed roll to form a paper sheet stop and then to engage said feed backpressure roll with a sheet of paper stopped by said feed-registering roll and clamp the sheet of paper against said feed roll for feeding the sheet of paper when said feed roll rotates.

References Cited in the file of this patent UNITED STATES PATENTS 1,023,869 Osborn Apr. 23, 1912 2,214,751 Pierce Sept. 17, 1940