Electrical pulse counters – pulse dividers – or shift registers: c – Applications – Counting animate or inanimate entities
Reexamination Certificate
1998-12-04
2001-11-27
Wambach, Margaret R. (Department: 2816)
Electrical pulse counters, pulse dividers, or shift registers: c
Applications
Counting animate or inanimate entities
Reexamination Certificate
active
06324237
ABSTRACT:
The invention relates to sheet counting apparatus and methods of counting sheets, for example for counting flexible sheets such as banknotes or other security type documents. The apparatus and method can also be used for verifying the total number of sheets within a preformed bundle or stack of such sheets.
Many machines have been described and implemented in the past for counting stacks of sheets such as banknotes in which the stack remains intact. A recent example is EP-A-0616300. In this case, rotatably mounted suction spindles are mounted for movement past the bundle of sheets to be counted/verified, each spindle rotating so as to lift the attracted sheet away from the adjacent sheet in the stack to an extent that the following spindle is moved into the space between the sheets while at substantially the same time it attracts a following sheet to be counted. The change in suction pressure is used to count the sheets. Similar devices are described in GB-A-2039112, GB-A-2038521 and GB-A-2152212.
DE-A-239888 discloses a further example in which a lifting and transporting carrier roller lifts sheets from the stack to the counted position. The number of rotations of this drive roller is used to count the number of notes.
DE-A-557407 describes a sheet picking mechanism in which a number of fingers are attached to the circumference of a grab disc and a carrier is provided near each finger which switches a counter disc from which the number of sheets counted can be read.
In all these known systems, sheets are counted indirectly. That is, the systems assume that a sheet is correctly moved from the first to the second position by monitoring aspects of the system such as a change in vacuum level or the like. Clearly, in the case of banknotes and the like, there is a significant problem if there is a miscount.
In accordance with one aspect of the present invention, a method of counting sheets held together in a stack comprises moving the sheets individually from a first position to a second position while they remain held together in the stack; monitoring movement of the sheet as it is moved from the first position to the second position; and incrementing a count when such a movement is detected.
In accordance with a second aspect of the present invention, sheet counting apparatus comprises a sheet support for holding a stack of sheets to be counted; a sheet feed device for moving the sheets individually from a first position to a second position while they remain held together in the stack; and a counter for monitoring movement of the sheet as it is moved from the first position to the second position, and for incrementing a count when such movement is detected.
In contrast to the known systems, the invention directly monitors movement of the sheet itself as it is moved from the first position to the second position. It does not rely on-monitoring some other aspect of the system and thus significantly increases the reliability of the count.
Movement could be monitored by viewing the sheets as they are counted, for example by irradiating the sheets from a laser beam or the like and monitoring reflected light, the degree of reflection varying as the sheet is moved.
In the preferred arrangement, however, the monitoring step comprises engaging a leading sheet in the stack with a sensing member and monitoring movement of the sensing member. By using a sensing member which engages the leading sheet in the stack, a very positive and reliable response is obtained upon movement of the sheet.
Typically, vibratory movement of the sensing member is monitored. This could involve simply determining whether or not the sensing member is vibrating but in a more sophisticated approach, which minimises error due to noise and the like, the monitoring step comprises comparing the vibration frequency with a threshold and determining that movement of the sheet is occurring if the vibration frequency exceeds the threshold.
This is advantageous over known edge detection systems such as described in U.S. Pat. No. 4,974,237 in that it is independent of edge quality. Furthermore, the apparatus is advantageous over the example described in U.S. Pat. No. 3,826,487 since it is independent of thickness and is not limited to detecting sheets on a transport.
The arm movement detector can be provided by a vibration sensor of any convenient contact or non-contact type but typically comprises a piezo-electric device.
Preferably, the counter comprises an arm which engages a sheet stack in the sheet stack support in use, and an arm movement detector. Various types of arm movement detector are known as shown, for example, in U.S. Pat. No. 3,826,487 and U.S. Pat. No. 4,974,237.
Preferably, an end of the arm which engages the sheet stack is provided with an uneven material to promote vibratory movement. This material could be an abrasive material.
The sheet feed device can be of any conventional type including spindle counters and the like as described in any of the prior art documents mentioned above. In a preferred arrangement, the sheet feed device comprises a sheet feed member mounted to rotate about its own axis and positioned so as to engage a stack of sheets held by the sheet support; and means for rotating the sheet feed member, the arrangement being such that rotation of the sheet feed member causes free ends of successive sheets in the stack to be moved between the sheet feed member and the remainder of the stack towards the other ends of the sheets in the stack, in the direction of rotation of the sheet feed member, and so to the second position while the sheets remain held by the sheet support.
This is much simpler than the known suction spindle apparatus and thus is less prone to failure and will have a reduced manufacturing cost. A further advantage is that it is more tolerant of misalignment of the ends of sheets and sheet edge condition than a suction spindle counter.
The sheet feed member typically comprises a friction feed roller whereby upon rotation of the sheet feed member, frictional engagement between the sheet feed member and an adjacent sheet causes the sheet to be moved to the counted position. Typically, the sheet feed member will have a high friction surface.
The sheet feed member could, however, comprise a suction member such as a rotatable roller having at least one hole connected to a vacuum source so as to suck an adjacent note onto the roller as the roller passes the stack and to carry the note to the counted position.
Although the apparatus could be implemented with a single sheet feed member, in some applications more than one sheet feed member could be provided mounted substantially coaxially. This assists in the counting of relatively wide sheets.
The biassing means could be provided by a controlled mechanism which moves one or other or both of the sheet support and the sheet feed member towards each other in a controlled manner during the counting operation. Conveniently, however, the biassing means comprises a resilient member such as a tension spring.
The or each sheet feed member could be directly driven by the rotating means but in the preferred arrangement the or each sheet feed member is mounted to a spindle which is connected to a pivoted arm allowing movement of the spindle and hence the sheet feed member towards and away from the sheet support. In some cases, the or each sheet feed member can be rotatably mounted to the spindle but this requires that each sheet feed member is independently driven. Conveniently, therefore, the or each sheet feed member is non-rotatably mounted to the spindle which is rotatably mounted to the pivoted arm.
The invention also extends to a sheet movement sensing assembly comprising a sensing member which is urged towards and engages a sheet in use; and a vibration sensor for sensing vibratory movement of the sensing member due to the passage of the sheet. Such an assembly could be used in other types of apparatus such as sheet transports and the like in which sheets are bodily moved past the sheet sensing assembly.
REFERENCES:
patent: 3826487 (197
Ayre Gareth James
Price John Gerwyn
De La Rue International Limited
Oliff & Berridg,e PLC
Wambach Margaret R.
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