US3352554A

US3352554A - Device for separating two superimposed moving sheets

Info

Publication number: US3352554A
Application number: US562694A
Authority: US
Inventors: Menzi Ulrich; Grigereit Helmut
Original assignee: Ciba AG
Current assignee: BASF Schweiz AG
Priority date: 1965-07-06
Filing date: 1966-07-05
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14
Also published as: SE323879B; BE683665A; CH430451A; NL6609041A; GB1141076A

Description

Nov. 14, 1967 u. MENZI ETAL DEVICE FOR SEPARATING TWO 'SUPERIMPOSED MOVING SHEETS Filed July 5, 1966 2 Sheets-Sheet l Ulric/'1 MenzL He Lrhut G'rr ger-e'ds Nov. 14, 1957 'u. MENZI ETAL 3,352,554

DEVICE FOR SEPARATING TWO SUPERIMPOSED MOVING SHEETS Filed July 5, 1966 2 Sheets-Sheet 2 a Q amaaamwgwqguymwaragm 5 5 5 5 *xmwxmmwmwmmm ULrfcJw Menzi. HeLmu'lz Grl'yere'rl:

1M, JW 2, Wm My United States Patent 9 Claims. (Cl. 271-64) The invention relates to a device for separating two superimposed moving sheets.

A separating device has been proposed for use in a blueprint copying apparatus, for example, and comprises a separating element spaced from a feed cylinder the separating element being a second cylinder which operates as a feed cylinder for the conveying of the superimposed sheets until operation of a switch reverses the direction of rotation thereof the switch being operated by the sheets which are to be separated. One of the first disadvantages of this device can be seen in the fact that as soon as the sheet opposite the separating cylinder (copy) has been lifted up the second cylinder then rubs against the back of the original, which remains between the two cylinders, and thereby tends to push this back also. As a result of the difiercnt directions of rotation of the cylinders, great stress is imposed on the original and this can lead to serious damage of the original, particularly in the case of thin and/or especially delicate originals. Moreover, to secure a satisfactory continuance of the feed of the original, which is now heavily braked, an additional feed device has to be disposed after the separating device. The adjustment of the distance between the two cylinders presents difiiculties and makes great demands on the mounting and truth of rotation of the two cylinders. Finally, the separation of the sheets does not always function perfectly and so the sheet which has been pushed back is very likely to become tangled in the copying apparatus. This applies especially when the flank of the developing look in the copy sheet nearest the second cylinder comes into a position tangential to the second cylinder, so that in fact there is no actual lifting of the copy sheet Off the second cylinder.

In order to remedy this last point in particularly, an arrangement was proposed which made the second cylindere rotate in the backward transporting direction all the time and in which the distance between the two cylinders can be so adjusted that at any given time just one sheet only is able to pass therebctween. The difiiculty in this arrangement lies in the correct adjustment of the distance between the two cylinders which must be of such dimensions that one sheet is reliably conveyed through but a second sheet lying thereon is just as reliably held back. For reasons of safety (failure of the separating device) moreover, the original has then to be conveyed through the cylinders; in the case of oflice copying machines however, this may cover the range from very thin (air mail) up to very thick, cardboard-like papers so that the distance has to be set individually for every thickness of the original, which is disadvantageous with regard to the operating of the apparatus.

A further proposed sheet separating device likewise provides, as a solution of this adjusting problem a separating element in the form of a cylinder rotating in the backward feed direction which has to be swung in manually into position and then swung out again after the sheets have been separated. Of course in a manually operated construction this arrangement is relatively simple, but with a corresponding automatic form it entails an expenditure which is excessive for the simpler applications (e.g. the simpler ofiice copying machines).

In conclusion, another proposed separating device subdivides the feed cylinder and also a counter-cylinder rotating in the backward direction into single, mutually olfset roller and disc segments, the counter-elements of which are formed of flat belts which are stretched through between the single roller and disc segments. This arrangement reduces the opposed frictional forces acting on the individual sheets to be separated and yet this solution is also extremely troublesome, makes considerable demands on the correct adjustment of rollers and belts and its reliability of functioning is limited.

The object of the invention, therefore, is to create a separating device especially for ofiice copying apparatuses which, at low cost and with the maximum protection of the sheet material, ensures the perfect and functionally dependable separation of two moving sheets, one lying upon the other.

The invention provides a device for separating two superimposed sheets comprising (a) a rotatable feed cylinder over which the sheet to be separated are intended to be passed,

(b) a rotatable shaft spaced from and axially parallel to the feed cylinder,

(c) an outwardly projecting elastic flap mounted on the shaft,

(d) a switch actuatablc by the sheets when at least a part of the sheets has passed over the feed cylinder,

(c) drive means for rotating the shaft one revolution, when the switch is actuated, in a direction counter to the direction of rotation of the feed cylinder whereby the flap presses the sheets against the feed cylinder and is deformed such that the sheet adjacent the feed cylinder will continue in its original direction of travel and the sheet remote from the feed cylinder will be deflected into a different direction of travel.

The advantages of the separating device according to the invention can be seen from the following points:

(1) The free entry of the sheets which are to be separated into the separating device preserves the sheet material and simplifiers the entry mechanism.

(2) Through the use of a rotating elastic flap which, under elastic deformation, presses the sheets which are to be separated for a short time against the feed cylinder, the adjustment of the distances between the two separating elements loses its importance.

(3) In consequence of the single rotation of the separating element the sheets to be separated are pressed to gether for a minimum period and any contact between the counter-element and the remaining sheet is precluded.

(4) As a result of the recoil of the elastically deformed flap into its position of rest after the actual separating process, the lifted sheet is flung into its new path and so any entanglement of this sheet in the separating mechanism is precluded.

The separating device according to the invention and also the coupling elements required for the execution of one single rotation of the separating element are explained in greater detail in the case of an ofiice copying machine below, with reference to the drawings in which:

FIGURE 1 shows in a perspective diagram the essential separating elements according to the invention;

FIGURES 2-4 are sections through the arrangement in FIGURE 1 showing different stages of the separating process and FIGURE 5 shows the separating device of FIGURES 1-4 with the associated coupling elements.

As shown in FIGURE 1, rubberized cylinder 1 rotates in the direction marked by an arrow and acts simultaneously as feed cylinder for sheets 4 (copy) and 5 (original) which are to be separated. Disposed above the cylinder 1 and parallel to it is a shaft 2 which is covered with a rubber profile 3 which has a flap 3a. In the first phase of the separating process, shown in FIG- URE 2, the flap is not in contact with the copy sheet 4 the separating device being in its neutral position.

The sheets are pushed over the cylinder 1 and operate a switch 13 which initiates rotation of the shaft 2 in the clockwise direction (FIGURE 2).

FIGURE 3 shows the operational phase of the shaft 2 in which the flap 3a presses the sheets on to the feed cylinder 1. Since the coefficients of friction between the cylinder 1 and the original 5, on the one hand, and between the flap 3a and the copy sheet 4, on the other, are greater than the coeflicient of friction between the original and the copy sheet 4, the original as moved onwards in the direction of the arrow, while on the other hand the copy sheet 4 is pushed backwards and therby forms a hump indicated by 4'.

Finally, FIGURE 4 shows a last phase before the shaft 2, or rather the flap 3a, has returned to its neutral position. The flap which has been bent back considerably in an elastic manner by the counterpressure of the cylinder 1 (FIGURE 3) is now released suddenly and jerks back into its relative neutral position. The sheet 4 thus flung away simultaneously by the separating device, so that the risk of entanglement of the copy in the separating device, cap be eliminated.

The following features are essential to the perfect functioning of the device according to the invention:

The shortest distance between the rubber profile 3 on the shaft 2 or the base of the flap 3a and the surface U of the feed cylinder 1 should be selected to be so small that the flap 3a can just be pulled between the shaft 2 and the feed cylinder 1. This distance depends substantially on the elasticity of the flap 3a and on the torque which should or can be applied to the shaft 2. In order to ensure reliable sheet separation, larger flap lengths I must be accepted in the case of greater distances, which however is disadvantageous in its eflect on the separation operation. It has been found that optimum results are obtained if the distance between the rubber profile 3 and the periphery U of the feed cylinder is about twice the thickness d of the flap 3a.

The distance s between the point of contact K of the sheet 5 and the periphery U of the feed cylinder 1 and the feeler of the switch 13 triggering the rotation of the shaft 2 is slightly smaller than or equal to the radius r, which is described by the end R of the flap 3a with the length l on rotation of the shaft 2, the optimum dimensioning depending on the relative speed between the advance of the

sheets

4 or 5 and the speed of rotation of the shaft 2 or of the flap 3a respectively, taking into account the retardation time between response of the feeler of the switch 13 to the beginning of the rotation of the shafts 2. If s is substantially smaller than r, both

sheets

4 and 5 are diverted into the new path; if on the other hand s is greater than r, the dependable lifting of the sheet 4 off the sheet 5 lying therebeneath is no longer ensured.

The mechanical feeler illustrated may also be replaced by a light barrier or the like.

Instead of using a profile 3 with a flap 3a extending the whole length of the shaft 2 it is possible to use a profile with several individual flaps 3', 3" (FIGURE 5); in this way stiffening, such as occurs after some time and with certain materials, especially rubber, in full-length flaps can be avoided. Also the fractional pressure on the copy sheet is more even. It is obvious that other suitable elastic materials apart from rubber can be used to form the profile 3.

FIGURE 5 shows a coupling mechanism according to the invention for initiating a single rotation of the shaft 2. The latter has at its end a rigidly mounted driving plate 12 and a sprocket wheel 7 which is straightened at one place in such a manner that a continuously moving chain 6, which may be the general driving chain for the copyingapparatus, is prevented from driving the sprocket wheel 7 when the separating device is in the neutral position. A magnet 9, the winding of which is energized by the switch 13 via a lead 14, has an armature 15 at the free end of which a pawl 11 is articulated. The pawl 11, when in the neutral position, engages with a driving pin 10 on V p the driving plate 12.

When the sheets to be separated enterthe separating device, the switch 13 is operated, current flows through the exciting winding of the magnet 9 and the armature is drawn up. The pawl 11 turns the driving plate 12 through the driving pin 10 in a counterclockwise direction and with it the shaft 2 and the sprocket wheel 7. The sprocket wheel 7 engages with the chain 6, whereby a leaf spring 8 ensures correct engagement of the teeth of the sprocket wheel 7 with the links of the chain 6. The sprocket wheel, driving plate, shaft 2 and rubber profile 3 now execute a full revolution. On return to its initial position the sprocket wheel 7, owing to pressure from the spring 8 via the chain 6 on the flat chord of the sprocket wheel, remains in the neutral position and hence also do the shaft 2 and the profile 3.

When the original 5 has finally passed right through the separating device and released the switch 13 again, the armature 15 of the magnet 9 drops back into its starting position. The pawl 11 engages with the driving pin 10 and thus the separating device is now-and not until now--ready again for the next separating operation. This precludes false rotations of the shaft 2 and with it the profile 3, which contributes substantially to the protection of the original 5 and the reliability of the separating process.

If, for any reason, there should nevertheless be some failure in the separating device the original and the copy are passed unseparated to the delivery point of the copying apparatus. Thus any misdirection of the original to some developing and fixing station is rendered impossible.

Of course the separating device according to the invention can be used, not only in the case of office copying machines, but in all application where two moving sheets, one on top of the other, have to be separated.

What is claimed is:

p 1. A device for separating two superimposed sheets comprising (a) a rotatable feed cylinder over which the sheets to be separated are intended to be passed,

(b) a rotatable shaft spaced from and axially parallel to the feed cylinder,

(c) an outwardly projecting elastic flap mounted on the shaft,

(d) a switch actuatable by the sheets when at least a part of the sheets has passed over the feed cylinder,

(c) drive means for rotating the shaft one revolution,

when the switch is actuated, in a direction counter to the direction of rotation of the feed cylinder whereby the flap presses the sheets against the feed cylinder and is deformed such that the sheet adjacent the feed cylinder will continue in its original direction of travel and the sheet remote from the feed cylinder will be deflected into a different direc tion of travel.

2. The device of claim 1, wherein the elastic flap is a tangential extension of a sleeve fitted around said shaft, the sleeve being made of rubber.

3. The device of claim 1, wherein a plurality of elastic flaps is mounted in coplanar relationship on said shaft.

4. The. device of claim 1, wherein the drive means comprises a sprocket wheel mounted at one end of the shaft and rotatable therewith, driver means also mounted at said one end and rotatable with said shaft said sprocket wheel having a flattened portion along one chord thereof, chain drive means, spring means for urging the chain drive into contact with said sprocket wheel, whereby the chain drive will be in driving engagement with the sprocket wheel except when the chain is in contact with the flattened portion of said sprocket wheel.

5. The device of claim 4, wherein the driver means consists of a driving plate, a pin being mounted on said driving plate, the drive means further comprising a magnet energisable on actuation of said switch, an armature comprised in said magnet, a pawl articulated on said armature and being normally in engagement with the pin, whereby when the magnet is energised, movement of the armature causes the pawl to urge the pin in a direction such that the driving plate and with it the sprocket Wheel rotate whence the sprocket wheel is brought into driving engagement with the chain drive.

6. The device of claim 1, wherein the distance between base of the flap and the curved surface of the feed cylinder, when the base of the flap is nearest to the feed cylinder, is at least about twice the thickness of said flap.

7. The device of claim 1, wherein the switch is arranged to actuate rotation of the shaft at an instant such that the outer axially parallel end of the flap Will strike the leading edge of the sheet remote from the feed cylinder.

8. The device of claim 7, and comprising a feeler for actuating said switch, the feeler being positioned at the intersection of the rotational path of the outer axially parallel end of the flap and the path of the sheets to be separated.

9. The device of claim 8, wherein the distance between the point of contact of the sheets to be separated and the feed roller and the feeler is substantially equal to or just less than the radius described by the outer axially parallel end of the flap on rotation of the shaft.

References Cited UNITED STATES PATENTS 3,017,179 12/1962 Stuckens 27118 RICHARD E. AEGERTER, Primary Examiner.

Claims

1. A DEVICE FOR SEPARATING TWO SUPERIMPOSED SHEETS COMPRISING (A) A ROTATABLE FEED CYLINDER OVER WHICH THE SHEETS TO BE SEPARATED ARE INTENDED TO BE PASSED, (B) A ROTATABLE SHAFT SPACED FROM AND AXIALLY PARALLEL TO THE FEED CYLINDER, (C) AN OUTWARDLY PROJECTING ELASTIC FLAP MOUNTED ON THE SHAFT, (D) A SWITCH ACTUATABLE BY THE SHEETS WHEN AT LEAST A PART OF THE SHEETS HAS PASSED OVER THE FEED CYLINDER, (E) DRIVE MEANS FOR ROTATING THE SHAFT ONE REVOLUTION WHEN THE SWITCH IS ACTUATED, IN A DIRECTION COUNTER TO THE DIRECTION OF ROTATION OF THE FEED CYLINDER WHEREBY THE FLAP PRESSES THE SHEETS AGAINST THE FEED CYLINDER AND IS DEFORMED SUCH THAT THE SHEET ADJACENT THE FEED CYLINDER WILL CONTINUE IN ITS ORIGINAL DIRECTION OF TRAVEL AND THE SHEET REMOTE FROM THE FEED CYLINDER WILL BE DEFLECTED INTO A DIFFERENT DIRECTION OF TRAVEL.