GB2165222A - Sheet separation apparatus - Google Patents

Abstract

Sheet separation apparatus for use, for example, in banknote counting apparatus comprises two pairs of rollers (10, 19) spaced apart to define a separation slit (38) through which only single sheets can be fed. One roller (19) of each pair is driven so that sheets are fed through the separation slit (38). A pair of temperature compensator arms (40) are mounted to the housing (1) and are arranged to cause relative movement between the first and second facing surfaces defined by the rollers (10, 19), the temperature compensator arms (40) being such that the size of the separation slit is maintained substantially constant during changes in temperature within an operating range. The arms may be made of a polyacetal material which expands or contracts with temperature change and causes repositioning of shaft (42) carrying a cam (25) acting on cradle (22) supporting rollers (19). <IMAGE>

Description

SPECIFICATION Sheet separation apparatus The invention relates to sheet separation apparatus particularly for use in sheet counting or sorting apparatus, for example banknote counting apparatus.

It is particularly important when counting or sorting sheets such as banknotes that the sheets are fed singly past the counting sensors in the apparatus. For example, in one counting machine banknotes are stacked at an input station and then fed past a note sensor such as an LED and photodetector arranged on opposite sides of a feed path to a stacking wheel where they are stacked at an output station. It is necessary to provide some means to ensure that notes are fed singly from the stack at the input station past the sensor. This is commonly achieved by causing the notes to be fed through a narrow separation slit defined between a pair of facing surfaces usually provided by a pair of rotating wheels.It is important that the width of this separation slit is accurately controlled since a small increase in width can cause more than one sheet to be fed through the slit resulting in an erroneous count while a small decrease in the width will cause sheets to jam.

One of the problems which has arisen with this known sheet separation apparatus is that during use changes in temperature of the various components of the apparatus occurs leading to expansion and contraction of the components by varying amounts since some components are metal and others are made of a plastics material. The combined result of the varying thermal expansions and contractions can cause considerable variations in the width of the separation slit. For example, a typical width of the slit is 0.1 mm (0.004") at 20"C. However, in use when a change in temperature to 45oC occurs, the slit width can change by 0.1 mm which is very undesirable.

In accordance with the present invention sheet separation apparatus comprises a housing; first and second facing surfaces supported by the housing and spaced apart to define a separation slit through which only single sheets can be fed; sheet feed means for feeding sheets through the separation slit; and temperature compensator means mounted to the housing and arranged to cause relative movement between the first and second facing surfaces, the temperature compensator means being such that the size of the separation slit is maintained substantially constant during changes in temperature within an operating range.

The invention provides a solution to the problem outlined above by providing temperature compensator means which acts to maintain the size of the separation slit despite variations in temperature causing variable expansion and contraction of the components of the apparatus.

Although both of the first and second surfaces could be moved relatively to the housing, conveniently, one of the first and second facing surfaces is fixed relatively to the housing while the other is movable towards and away from the one facing surface under the control of the temperature compensator means.

In practice, the sheet feed means may comprise one or both of the first and second facing surfaces which are movable to feed sheets through the separation slit. Typically, the first and second facing surfaces would be provided by at least one pair of rollers, one of the pair of rollers being rotatably driven in use.

Alternatively, the first and second facing surfaces could be provided by at least one pair of conveyor belts.

Preferably, where one surface is fixed relatively to the housing, the other surface is mounted on a support which is pivoted to the housing, the pivotal position of the support being controlled by an actuator and the temperature compensator means being connected between the housing and the actuatorwhereby expansion or contraction of the temperature compensator means in response to temperature changes causes movement of the actuator and consequential pivotal movement of the support. In an alternative arrangement, the temperature compensator means could act directly between the housing and the pivoted support.

Conveniently, the actuator comprises a cam rotatably mounted to the housing, the cam being rotatable to set an initial separation slit width and being linearly movable relatively to the housing by the temperature compensator means. To achieve this, the cam may be mounted on a shaft which is supported by the temperature compensator means and may, for convenience, extend through one or more elongate slots in the housing to enable the cam to be manually rotated initially.

Preferably, the temperature compensator means comprises two compensator arms.

The operating range of temperature is preferably from 5"C to 45"C ambient, although the actual machine temperature due to internal heating may reach 55"C.

An example of banknote counting apparatus incorporating apparatus in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of the apparatus with the temperature compensator arms omitted; Figure 2 is a part sectional view illustrating the stripper means and transport means in more detail; Figure 3 is a view taken on the line 3-3 in Figure 2; Figure 4 is a simplified side view similar to Figure 1 but showing the temperature compensator arm; and, Figure 5 is a part sectional view illustrating the stripper means and adjuster cam in more detail.

The apparatus illustrated in the drawings is a banknote counting apparatus (for example our 2300 machine) but for clarity the means for detecting the banknotes passing through the apparatus to enable the notes to be counted has been shown only schematically. This will however be of a conventional form.

The apparatus comprises a metal housing 1 supporting a base plate 2 and an end plate 3 of an input hopper 4. Two conventional picker wheels 5 are rotatably mounted to the housing 1 and have radially outwardly projecting bosses 6 which, as the picker wheels rotate, periodically protrude through slots in the base plate 2.

A guide plate 7 having a curved guide surface 8 is pivotally mounted by an arm 7' to a lug 9 attached to the end plate 3. Two separation rollers 10 (only one shown in the drawings) are rotatably mounted to a shaft 11. A cantilevered arm 12 is connected to the guide plate 7 and includes a spring clip 13. When the guide plate 7 is in its first position shown, the spring clip 13 is located around a stationary shaft 14. If it is desired to cause the plate 7 to pivot away from its first position, the clip 13 is simply unclipped from the shaft 14 and pivoted in an anti-clockwise direction (as seen in Figure 1) allowing the operator access to the note feed path so that a note jam can be cleared.

A pair of drive rolls 15 are non-rotatably mounted to a drive shaft 16 which is rotatably mounted to the housing 1. Each drive roll 15 has an outer annular portion 17 of rubber. Each drive roll 15 contacts a respective auxiliary roll 18 rotatably mounted on the shaft 14. For clarity, the guide plate 7 has been omitted from Figure 2.

A stripper roller 19 is rotatably mounted on a shaft 20 having a larger diameterthan the shaft 16 about which it is positioned. The shaft 20 is secured between a pair of arms 21 of a cradle 22. The cradle 22 is rotatably mounted to an auxiliary drive shaft 23 on which the picker wheels 5 are mounted. The cradle 22 has a cam portion 24 which engages a cam 25 on a shaft 42 rotatably mounted to a pair of temperature compensator arms 40 (Figure 5). (The cam 25 has been omitted from Figure 3) Manual rotation of the cam 25 via a knob 41 connected to the shaft 42 moves the stripper roller 19 towards the separation rollers 10 to define a separation slit 38. A portion of the outer surface of the stripper roller 19 is formed by a rubber section 26. The stripper roller 19 also has a central, annular, toothed groove 27.The auxiliary drive shaft 23 carries non-rotatably a toothed drive wheel 28 mounted in alignment with the groove 27 of the stripper roller 19. Atoothed drive belt 29 extends around the drive wheel 28 and into engagement with that part of the groove 27 remote from the auxiliary drive shaft 23.

A drive motor 30 (shown schematically in Figure 1) continuously drives the drive shaft 16 via a drive belt 31. The connection between the drive belt 31 and the drive shaft 16 has been omitted for clarity. The auxiliary drive shaft 23 Is driven via a drive belt 32 by a drive motor 33.

A guide plate 34 extends from adjacent the nips formed between the drive rolls 15 and auxiliary rolls 18 to a conventional stacker wheel 35 rotatably mounted on the housing 1. The guide plate 34 together with an end plate 36 define an output hopper 37.

In use, a stack of banknotes is placed in the input hopper 4. The drive motors 30,33 are actuated so that both the drive shaft 16 and the auxiliary drive shaft 23 rotate. Rotation of the picker wheels 5 causes banknotes at the bottom of the stack to be urged towards the separation gap 38 between the stripper roller 19 and the separation rollers 10. The separation rollers 10 have been omitted in Figure 2 for clarity. As the stripper roller 19 rotates in response to the rotation of the auxiliary drive shaft 23, the rubber section 26 will engage the adjacent note and carry this note past the guide surface 8 and into the nip formed between the axiliary rolls 18 and drive rolls 15. The gap between the stripper roller 19 and separation rollers 10 is chosen to prevent more than one note being fed by the stripper roller 19.

Detection means 39 (shown in phantom) including a controlling microcomputer will check the note fed for authenticity and if it determines that the note is not authentic, the drive motor 33 will be braked so that the shaft 23 will stop and the stripper roller 19 will stop rotating and thus prevent further notes from being fed from the stack in the input hopper 4.

However, irrespective of the decision of the detecting means, the note will be fed between the drive rolls 15 and the auxiliary rolls 18 due to the continuous rotation of the shaft 16, the note being fed along the guide plate 34 into the stacker wheel 35 which is being rotated by the drive motor 30 and which will stack the note fed in the output hopper 37.

If that note is not authentic then no more notes will be fed from the input hopper 4 and it is a simple matter for the operator to pick the bad note from the top of the stack in the output hopper 37.

As may best be seen in Figure 2, it is desirable for the outer surface of the stripper roller 19 adjacent the nips between the rollers 15, 18 to be aligned with the nips. This is so that the rubber portions 26 will not rub the notes so that there is no significant wear and the notes are not dragged into the feed.

Figures 4 and 5 illustrate in more detail the relationship between the temperature compensator arms 40 and the rest of the apparatus. Two temperature compensator arms 40 of a plastics material such as polyacetal (e.g. Delrin - Registered Trade Mark) are provided which are fixed by respective bolts 43 to respective side plates 44 of the housing 1. The arms 40 each have a typical thermal expansion of 90 x 10-6 mmXmm/5C. The shafts 11,23 are rotatably mounted between the side plates 44. The side plates 44 have a pair of aligned apertures 45 through which the shaft 42 carrying the cam 25 extends. The apertures 45 are slot shaped to allow the shaft 42 to be moved relatively to the side plates 44. The shaft 42 is supported by the two compensator arms 40 between which it is rotatably carried. The length of each compensator arm 40 between the shaft 42 and the respective bolt 43 is 53 mm.

In use, if a change in temperature occurs which results in the separation gap 38 increasing then the temperature compensator arms 40 will contract drawing the shaft 42 upwards, as seen in Figure 5.

This upward movement will tend to reduce the size of the separation gap 38 and thus compensate for the change produced by contraction of the other components. Conversely, if a temperature change causes a decrease in the size of the separation gap to occurthen the compensator arms 40 will expand to cause downward movement of the shaft 42, as seen in Figure 5, thus tending to increase the size of the gap 38 and compensate for the temperature change.

In the example, mentioned above where the effective portion of each arm has a length of 53 mm, the expansion of the arm for a 259C temperature rise is: 90 x 10-6 x 53 x 25 = 0.12 mm.

Claims (8)

1. Sheet separation apparatus comprising a housing; first and second facing surfaces supported by the housing and spaced apart to define a separation slit through which only single sheets can be fed; sheetfeed meansforfeeding sheets through the separation slit; and temperature compensator means mounted to the housing and arranged to cause relative movement between the first and second facing surfaces, the temperature compensator means being such that the size of the separation slit is maintained substantially constant during changes in temperature within an operating range.

2. Apparatus according to claim 1, wherein one of the first and second facing surfaces is fixed relatively to the housing while the other is movable towards and away from the one facing surface under the control of the temperature compensator means.

3. Apparatus according to claim 2, wherein the other surface is mounted on a support which is pivoted to the housing, the pivotal position of the support being controlled by an actuator and the temperature compensator means being connected between the housing and the actuator whereby expansion or contraction of the temperature compensator means in response to temperature changes causes movement of the actuator and consequential pivotal movement of the support.

4. Apparatus according to any of claims 1 to 3, wherein the actuator comprises a cam rotatably mounted to the housing, the cam being rotatable to set an initial separation slit widthand being linearly movable relatively to the housing by the temperature compensator means.

5. Apparatus according to claim 4, wherein the cam is mounted on the shaft which is supported by the temperature compensator means.

6. Apparatus according to any of the preceding claims, wherein the temperature compensator means comprises two compensator arms.

7. Sheet separation apparatus substantially as hereinbefore described with reference to the accompanying drawings.

8. Banknote counting apparatus incorporating sheet separation apparatus according to any of the preceding claims.