GB2238895A - Sheet counting machine - Google Patents

Abstract

A sheet counting machine includes a rotatable cylinder (5), a plurality of suction tubes (6), and a counter for counting the number of sheets based upon the changes in pressure in a hollow shaft (4). After a set number N0 of sheets has been counted, the rotatable cylinder (5) is forced to stop at a timing so that the N0th sheet is superposed on a sheet stack consisting of first to (N0-1 )th sheets so as to form the stack of N0 sheets and the rotatable cylinder (5) is reversely rotated to return the (N0+1)th sheet to the initial stack (2) and is then stopped at a position where the suction opening (7) of one suction tube (6) faces the initial stack (2). <IMAGE>

Description

1 -p -;:, ' a tD S SHEET.COUNTING MACHINE 1 The present invention relate

to a sheet counting machine for counting sheets such as bank notes and, particularly, to a sheet counting machine which comprises a plurality of rotatable suction tubes formed on one end face of a rotatable cylinder so as to project therefrom, counts sheets by applying a vacuum pressure to the suction tubes, thereby to suck and turn over sheets held Py a holding means one by one, and is capable of collecting a stack of a predetermined number of sheets with a simple structure.

UK Patent Application GB 2 125 997 A discloses a sheet counting machine comprising a plurality of rotatable suction tubes projectingly formed on one end face of a rotatable cylinder so as to be equiangularly spaced from each other around a shaft of the rotatable cylinder at the same distance from the shaft, each of the suction tubes having a suction opening, and sheets such as bank notes being carried out by applying a vacuum pressure to the suction tube, thereby to suck and turn over the sheets he ld by a holding means one by one. In this sheet counting machine, vacuum pressure is applied by a vacuum pump to the shaft of the rotatable cylinder, which is formed to be hollow and the interior of only the suction tube positioned within a predetermined zone in which the suction tube faces the sheets held by the holding means communicates with the inside of the hollow shaft of the rotatable cylinder, whereby the sheet held by the holding means is sucked. The thus sucked sheet is turned over by the rotation of the rotatable cylinder and the suction tube and then an adjacent suction tube 2 which, in accordance with the rotation of the rotatable cylinder, has been moved into the predetermined zone in which it faces the sheets held by the holding means sucks and turns over the next sheet. In this manner, the sheets are successively sucked and turned over one by one and the number of sheets is counted by detecting changes in the pressure in the hollow shaft of the rotatable cylinder caused by the suction of the sheets.

This sheet counting machine is constituted so that when a predetermined number of sheets has been counted, the stack of the predetermined number of sheets can be collected by separating it from the uncounted sheets held in holding means.

Conventionally, for the purpose of separating a prede- is termined number of counted sheets from uncounted sheets, a separating member is provided for pressing the surface of the next sheet after the last one of the predetermined number of sheets has been turned over by the suction opening of a suction tube, whereby the next sheet is prevented from being turned over and a stack made up predetermined number of sheets can be collected.

However, in the case where the next sheet is forcibly prevented from being turned ov er by pressing the separating member onto the surface thereof, since the next sheet has been already sucked by the suction opening of the suction tube, there arises a danger that the next sheet may be torn or that its surface may be damaged.

Therefore. Japanese Patent Disclosure Hei 2-19991

3 t is proposes a sheet counting machine of this kind having a sheet stack separating apparatus in which a plurality of magnetic strips are adhered onto the circumference of the rotatable cylinder, the positions of the magnetic strips are detected by a magnetic sensor for detecting the position of the rotatable cylinder and which can separate and collect a stack of a predetermined number of sheets by stopping the supply of vacuum pressure at the time the sheet following the predetermined number of sheet is sucked by the suction opening of a suction tube and counted and reversely rotating the rotatable cylinder until the following sheet sucked by the suction opening of the suction tube is returned into the holding means.

In this sheet counting machine, although there is no risk of the sheet being torn or having its surface damaged, since it is necessary to adhere the plurality of magnetic strips onto the circumference of the rotatable cylinder and to provide the magnetic sensor for detecting these magnetic strips, there arises a problem that the structure becomes complicated.

The object of the present invention is to provide a sheet counting machine capable of reliably separating and collecting a stack of a predetermined number of sheets with a simple structure.

The object of the present invention can be accomplished by a sheet counting machine comprising a sheet holder for holding sheets to he counted. a rotatable cylinder rotatable about a hollow shaft, motor means for rotating 4 1 f the rotatable cylinder, motor control means for controlling the operation of the motor means, a plurality of suction tubes projectingly formed on one end face of the rotatable cylinder so as to be equiangularly spaced from each other around the hollow shaft and be located at the same distance from the hollow shaft, each of the suction tubes having at least one suction opening, vacuum pump means for applying vacuum pressure to the hollow shaft, vacuum pump control means for controlling the operation of the vacuum pump means, communicating means arranged so as to communicate only the suction tube positioned within a predetermined zone in which it faces sheets held by the sheet holder among the plurality of suction tubes with the inside of the hollow shaft, pressure detecting means for detecting changes in is pressure in the hollow shaft produced by sucking and turning over the sheets held by the sheet holder by the vacuum pressure applied from the vacuum pump means, counting means for counting the number of sheets based upon the changes in pressure in the hollow shaft detected by the pressure de- tecting means, sheet number setting means for setting the number No of sheets to be separated and collected, and comparing means for judging whether or not the number of counted sheets coincides with the set number NO set by the sheet numb-er setting means based upon the output from the counting means and, when judging they coincide with each other, outputting a coincidence signal to the motor control means, thereby to cause the motor control means to stop the operation of the motor means, the sheet counting machine being characterized in that there.are provided first brake signal output means for outputting, after receiving the coincidence signal output from the comparing means, based upon the pressure in the hollow shaft detected by the pressure detecting means, a first brake signal to the motor control means so as to force the rotatable cylinder to stop at a timing so that the rotatable cylinder is stopped at the position where a Noth sheet is superposed on a sheet stack consisting of first to (NO -1)th sheets so as to form the stack of NO sheets and where even if the rotatable cylinder is reversely rotated afterward, the suction opening of the suction tube having sucked the Noth sheet cannot suck the Noth sheet, and second brake signal output means for receiving the f irst brake signal, outputting a reverse rotation signal to the motor control means so as to reversely rotate the rotatable cylinder after the rotatable cylinder has been stopped, outputting, based upon the change in pressure in the hollow shaft detected by the pressure detecting means, a reverse rotation stop signal to the motor control means so as to stop the reverse rotation of the rotatable cylinder and a drive stop signal to the vacuum pump control means so as to stop the supply of vacuum pressure to the interior of the hollow shaft from the vacuum pump means at a predetermined timing, and outputting a second brake signal to the motor control means at a timing so that the rotatable cylinder is stopped at a position where all of the at least one suction opening of one suction tube among the plurality of suction tubes face the surface of the sheet holder.

6 In a preferred aspect of the present invention, the sheet counting machine further comprises counting completion signal output means for monitoring the pressure in the hollow shaft detected by the pressure detecting means and outputting a counting completion signal to the first brake signal output means when the pressure in the hollow shaft increases to not more than a predetermined value after the counting means has started counting sheets so as to prevent the first brake signal output means from outputting the first brake signal and cause the first brake signal output means to output a drive stop signal to the vacuum pump control means and start monitoring the pressure in the hollow shaft input from the pressure detecting means, and is constituted so that when the first brake signal output means receives the counting completion signal from the counting completion signal output means, it Outputs, based upon the change in pressure in the hollow shaft detected by the pressure detecting means, a third brake signal to the motor control means at a predetermined timing so as to cause the motor means to force the rotatable cylinder to stop at a position where all of the at least one of suction opening of one suction tube among the plurality of suction tubes face the surface of the sheet holder.

In the accompanying drawings:

Figure 1 is a schematic drawing showing a plan view of 7 a bank note counting machine; Figure 2 is a schematic drawing showing a suction mechanism of a bank note counting machine; Figure 3 is a block diagram showing a sheet stack separating apparatus provided in a bank note counting machine; Figures 4 and 5 are graphs showing pressure curves of the pressure in a suction passage and a hollow shaft detected by a pressure sensor; Figure 6 is a graph showing enlarged view a part of the pressure curve of Figure 4; Figure 7 is schematic drawing showing a plan view of a is rotatable cylinder when a first brake signal is output and Figure 8 is a schematic drawing showing a plan view of the rotatable cylinder when it stops as the result of outputting the first brake signal; Figure 9 is a graph showing enlarged view of a part of the pressure curve of Figure 5; and Figure 10 is a graph showing enlarged view of a part of a pressure curve for another condition.

Referring to Figures 1 and 2. a bank note counting machine 1 has a holder 2 comprising a holding plate 2a on which a stack of bank notes B is placed and a press plate 2b which holds the stack of bank notes B in cooperation with the 8 holding plate 2a between itself and the holding plate 2a. The holder 2 is swingable about a shaft 3 in the horizontal plane between a waiting position shown by a solid line and a counting position shown by a single- dotted line and the holder 2 is held at the counting position when the number of bank notes is being counted, while it is held at the waiting position when the number of bank notes B is not being counted.

The bank note counting machine 1 further comprises a rotatable cylinder 5 rotatable about a shaft 4. The rotatable cylinder 5 has five suction tubes 6 arranged so as to project from one end face of the rotatable cylinder 5. The suction tubes 6 are spaced from each other by 72 degrees around the shaft 4 and are located at the same distance from is the shaft 4. A part of each suction tube 6 is formed with a suction opening 7. When a stack of bank notes B is accommo dated in the holder 2 or a start switch 9 is operated, the holder 2 is swung to the counting position and the counting operation is started. At this time, the suction opening 7 of one suction tube 6 among the plurality of suction tubes 6 is positioned so as to f ace and contact the surface of the top bank note of the stack of bank notes B (The top bank note is defined as the one on the side of the suction opening 7 in this specification.). In Figure 1, the refer- ence numeral 6a designates a cap of the suction tube 6.

As shown in Figures 1 and 2, the rotatable cylinder 5 is rotatable counterclockwise about the shaft 4 when it is forwardly rotated and each of the suction tubes 6 is rotata- 9 i ble clockwise by a gear mechanism (not shown) provided below a shaft 10 thereof when the rotatable cylinder 5 is rotated forwardly. Accordingly, when the rotatable cylinder 5 is forwardly rotated, each of the suction tubes 6 revolves clockwise on its axis and simultaneously revolves counterclockwise about the shaft 4. The cylinder 5 is driven in rotation by means of a motor 8 through a belt.

The shaft 4 of the rotatable cylinder 5 and the shaft 10 of each suction tube 6 are formed to be hollow and the interior of the shaft 4 is connected-to a vacuum pump 12 via a suction passage 11 so that a vacuum pressure is always applied to the interior of the shaft 4 when the vacuum pump is driven by a pump motor 13. Further, the interior of the shaft 10 of each suction tube 6 can be communicated with the interior of the shaft 4 via a communicating passage 14 and the communicating passage 14 is formed so as to communicate the interior of the shaft 10 of the suction tube 6 with the interior of the shaft 4 only when the center of the suction tube 6 is positioned within a suction zone S bounded by radial lines % and % in which the suction tube 6 faces the bank notes B, whereby the vacuum pressure is applied to the interior of the shaft 10 so that.the suction opening 7 of the suction tube 6, the suction opening facing the surface of the top bank note can suck the top bank note by the vacuum pressure applied thereto from the vacuum pump 12 via the suction passage 11. the interior of the shaft 4, the communication passage 14 and the interior of the shaft 10. The communicating passage 14 is formed so that the angle between the radial lines % and % is smaller than 72 de- grees and it is ensured that two or more suction tubes will not be simultaneously positioned within the suction zone S.

Further, in Figure 2, the reference numeral 15 designates a holder motor for swinging the holder 2 about the shaft 3 between the waiting position and the counting position and the reference numerals 16. 17 designate a light emitter and a light receiver. The surface of the top bank note B is exposed to light emitted from the light emitter 16 and light reflected from the surface of the bank note is received by the light receiver 17, whereby the denomination, genuineness and the like of the bank note 1 are discriminated by a discriminating means (not shown). There is further provided a pressure sensor 18 for detecting the pressure in the suction passage 11 and thus the pressure of the interior of the hollow shaft 4.

Figure 3 is a block diagram showing a bank note stack separating apparatus for separating a stack of a predetermined number of bank notes provided in a bank note counting machine.

In Figure 3, the bank note stack separating comprises start signal output means 21 for outputting a start signal when a start switch 9 has been operated or a bank note sensor 20 detects that bank notes B have been accommodated in the holder 2, holder position detecting means 22 for detecting whether the holder 2 is positioned at the waiting position or the counting position and outputting a holder position detection signal, holder motor control means 23 for controlling theoperation of the holder motor 15, pump motor control means 24 for controlling the operation of the pump motor 13. pressure signal output means 25 for A/D converting the detection signals indicating the pressure in the hollow shaft 4 and the suction passage 11 detected by and input from the pressure sensor 18 into digitized pressure signals and outputting them. counting start signal output means 26 for outputting a counting start signal when the absolute value of the rate of change of the pressure signal level output from the pressure signal output means 25 is not less than a predetermined value and the pressure signal level becomes not greater than a predetermined level, and. on the other hand, when the absolute value of the rate of change of the pressure signal level is less than the predetermined is value, outputting a positioning signal, and when the absolute value of the rate of change of the pressure signal level becomes not less than the predetermined value and the pressure signal level becomes not greater than a predetermined level after outputting the positioning signal. outputting the counting start signal, positioning control means 28 for outputting a reverse rotation signal to motor control means 27 for controlling the operation of the motor 8 for rotating the rotatable cylinder 5 when the positioning signal is input from the counting start signal output means 26, thereby to reversely rotate the rotatable cylinder 5, and outputting a reverse roation stop signal when the absolute value of the rate of change of the pressure signal level becomes not less than the predetermined value, the 12 motor control means 27 for driving the motor 8 so that the rotatable cylinder 5 is forwardly rotated when the counting start signal is input from the. counting start signal output means 26 and that, on the other hand, the rotatable cylinder 5 is reversely rotated when the positioning signal is input from the positioning control means 28, counting means 29 for counting the number of bank notes based upon the changes in the pressure signal level input from the pressure signal output means 25 after the counting start signal has been input from the counting start signal output means 26, bank note number setting means 30 for setting the predetermined nimber NO of bank notes to be separated and collected, the bank note number setting means 30 being constituted by a key board and the like and operated by an operator, comparing means 31 for outputting a coi ncience signal to the motor control means 27 so as to stop the operation of the motor 8 when it judges that the number N of counted bank notes B becomes equal to the predetermined number NO based upon the output from the bank note number setting means 30 and count- ing signals input from the counting means 29, first brake signal output means 33 which when it detects that the number of the counted bank notes N has become equal to the set number NO based upon the bank note detection signals input from the counting means, outputs a first brake signal to the motor control means 27 and a second brake signal output means 32, thereby to cause the motor 8 to force the rotatable cylinder 5 to stop.and cause the second brake signal output means 32 to start monitoring the pressure signals is output from the pressure signal output means 25. further outputs a count stop signal to the counting means to prevent it from counting the (NO + 1)th bank note, and. on the other hand, when a counting completion signal is input from counting completion signal output means 34, without outputting the first brake signal and the counting stop signal, outputs a pump stop signal to the pump motor control means 24 so as to cause the pump motor to stop the drive of the vacuum pump 12. starts monitoring the pressure signal output from the pressure signal output means 25 to detect the position of the suction tubes 6 based upon the changes in the pressure signal level produced by the rotatable cylinder 5 which continues to be rotated by inertia even though the application of vacuum pressure is stopped by the pump motor control means 24 and the motor 8 for rotating the rotatable cylinder 5 is stopped by the motor control means 27 and outputs a third brake signal to the motor control means 27 at a predetermined timing, thereby to cause the motor 8 to force the rotation of the rotatable cylinder 5 to stop. the second brake signal output means 32 for starting monitoring the pressure signals output from pressure signal output means 25 when receiving the first brake signal from the first brake signal output means 33. outputting a reverse rotation signal to the motor control means 27 so as to reversely rotate the rotatable cylinder 5 at a predetermined timing. then outputting a reverse rotation stop signal to the motor control means 27 so as to stop the reverse rotation of the rotatable cylinder 5 and simultaneously outputting a pump stop signal 14 to the pump motor control means 24 so as to cause the pump motor 13 to stop the operation of the vacuum pump 12, detecting the position of the suction tubes 6 based upon the changes in the pressure signal level produced by the rotatable cylinder 5 which continues to be rotated by inertia even though the application of vacuum pressure is stopped by the pump motor control means 24 and the motor 8 for rotating the rotatable cylinder 5 is stopped by the motor control means 27 and outputting a second brake signal to the motor control means 27 at a predetermined timing, counting completion signal output means 34 for outputting a counting completion signal when the pressure signal level input from the pressure signal output means 25 becomes not less than a predetermined level after the counting of bank notes B has been is started, and display means 35 for displaying the number of bank notes B counted in accordance with the counting signals output from the counting means 29 and the completion of the counting operation when the counting completion signal is input from the counting completion signal output means 34.

The thus constituted bank note counting machine 1 counts the number of bank notes 1 as follows.

At first, the number NO of bank notes B to be separated and collected as a stack is.input to the bank note number setting means 30 by an operator.

Then, when a stack of bank notes B has been set in the holder 2, the bank note sensor 20 outputs a bank note set signal to the start signal output means 21. The start signal output means 21 outputs a start signal to the holder motor is control means 23 and the pump motor control means 24 when the start signal has been input or the start switch 9 has been operated.

When the holder motor control means 23 has received the start signal from the start signal output means 21 and judges based upon a holder position detecting signal input from the holder position detecting means 22 that the holder 2 is positioned at its waiting position, it drives the holder motor 15 until it is judged based upon the holder position detecting signal input from the holder position detecting means 22 that the holder 2 has been positioned at its counting position and causes the holder 2 to be positioned at its counting position.

Further. when the start signal has been input from the start signal output means 21, the pump motor control means 24 drives the pump motor 13 so.that vacuum pressure is applied to the suction passage 11 and the inside of the shaft 4 of the rotatable cylinder 5.

As a result, the pressure in the suction passage 11 and the interior of the hollow shaft 4 begins to fall and the decrease is detected by the pressure sensor 18, whereby the pressure detection signal is out:put to the pressure signal output means 25. The pressure signal output means 25 A/D converts the pressure detection signal input from the pressure sensor 18 and outputs a digitized pressure signal to the counting start signal output means 26, the positioning control means 28, the counting means 29, the counting completion signal output means 34, the first brake signal 16 1 output means 33- and the second brake signal output means 32. When the pressure signal has been input and it is detected based upon a holder position detecting signal input from the holder position detecting means 22 that the holder 2 is positioned at its counting position, the counting start signal output means 26 starts to monitor the changes in the pressure signal level.

Figures 4 and 5 are graphs showing pressure curves of the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected by the pressure sensor 18. Figure 4 shows an example of the pressure curve in the case where the number N of the bank notes B set in the holder 2 is not less than (NO + 2) and the counting is started in the condition that the suction opening 7 of a suction tube 6 faces the surface of the top bank note B, and Figure 5 shows an example of the pressure curve in the case where the number N of the bank notes B set in the holder 2 is equal to (NO + 1) and the counting is started in the condition that no suction opening 7 of a suction tube 6 faces the surface of the top bank note B. As shown in Figure 4, when the pump motor control means 24 receives the start signal from the start signal output means 21, it drives the pump motor 13, thereby to cause the vacuum pump 12 to apply vacuum pressure to the suction passage 11 and the interior of the hollow shaft 4. By definition, when it is said that the suction opening 7 of a certain suction tube 6 faces the surface of bank note B, this means that the suction tube 6 is positioned within the 17 k suction zone S_ and, therefore, the interior of the hollow shaft 7 of the suction tube 6 communicates with the interior of the shaft 4 via the communicating passage 14, whereby vacuum pressure is applied onto the surface of the top bank note 1 of the stack of bank notes B and the top bank note B is sucked onto the suction opening 7 so as to close the suction opening 7. As a resulti the pressure in the suction passage 11 and the interior of the hollow shaft 4 falls at substantially a constant rate of change with elapse of time.

Then, when, based upon the pressure signal level input from the pressure signal outputting means 25, the counting start signal output means 26 detects that the pressure in the suction passage 11 and the interior of the hollow shaft 4 has fallen to a sufficient pressure for example, about is -620mmHg to be able to suck and turn over the bank note 1, it outputs a counting start signal to the motor control means 27 for controlling the operation of the motor 8 for rotating the rotatable cylinder 5. As a result. the rotata ble cylinder 5 is forwardly rotated counterclockwise in Figure 1 at a high speed about the shaft 4 and the suction tubes 6 are rotated clockwise by the gear mechanism provided below the shaft 10 of the suction tubes 6 in accordance with the rotation of the rotatable'cylinder 5, whereby the bank notes are turned over by the suction openings 7 of the suction tubes 6. In Figure 4, A shows the time at which the counting start signal was output.

On the contrary. in the case where the counting is started in the condition that no suction opening 7 of a 18 suction tube 6 faces the surface of the.top bank note B, the bank note 1 cannot be sucked by the suction opening 7 of the suction tube 6, even if the pump motor is driven and the vacuum pressure is applied to the suction passage 11 and the interior of the hollow shaft 4. Therefore, as shown in Figure 5, the pressure in the suction passage 11 and the inside of the hollow shaft 4 merely falls gradually and the absolute value of the rate of change of the pressure is smaller than that in Figure 4. In this case, since it is necessary, first of all, to position the suction opening 7 of the suction tube 6 so as to face the surface of the bank B. the counting start signal output means 26 outputs a positioning signal to the positioning control means 28. In Figure 5, B shows the time at which the positioning signal was output.

When the positioning control means 28 receives the positioning signal from the counting start signal output means 26, it outputs a reverse rotation signal to the motor control means 27 so that the rotatable cylinder 5 is re- versely rotated clockwise in Figure 1 at a low speed about the shaft 4 until the suction opening 7 of the suction tube 6 faces the surface of the top bank note B and, simultaneously, starts to monitor the pressure signal input from the pressure signal output means 25. Then, as shown in Figure 5, when the absolute value of the rate of change of the pressure signal input from the pressure signal output means 25 has become not less than the predetermined value, the positioning means 28 outputs a reverse rotation stop signal to 19 k the motor control means 271 thereby to stop the rotation of the rotatable cylinder S. During this period, the counting start signal output means 26 is also monitoring the pressure signal input from the pressure signal output means 25 and when, based upon the level of the pressure signal input from the pressure signal output means 25. itdetects that the pressure in the suction passage 11 and the interior of the hollow shaft 4 has fallen to a sufficient pressure to be able to suck and turn over the bank note B, for example, to about -620mmHg after it detects that the absolute value of the rate of change of the pressure signal input from the pressure signal output means 25 has become not less than the predetermined value, it outputs a counting start signal to the motor control means 27 for controlling the motor 8 for rotating the rotatable cylinder 5. As a result, the rotatable cylinder 5 is forwardly rotated counterclockwise in Figure 1 at a high speed about the shaft 4 and the suction tubes 6 are rotated clockwise by the gear mechanism provided below the shaft 10 of the suction tubes 6 in accordance with the rotation of the rotatable cylinder 5, whereby the bank notes are turned over by the suction opening 7 of the suction tube 6. In Figure 5, C shows the time at which the reverse rotation stop signal was output.

Thus, after a bank note B is sucked and turned over by the suction opening 7 of a suction tube 6 rotating clockwise about its own axis and rotating counterclockwise about the shaft 4, the suction tube 6 sucking the bank note 1 moves out of the suction zone S bounded by radial lines % and % j, and the next suction tube moves into the suction zone S. However, since no bank note B is sucked by the next suction tube 6 until the suction opening 7 thereof comes to face the surface of the top bank note B.f the'pressure in the suction passage 11'and the interior of the hollow shaft 4 detected by the pressure sensor 18 increases and the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected by the pressure sensor 18 does not fall until the suction opening 7 of the next suction tube 6 faces the surface of the top bank note B. Then, the suction tube 6 sucking the bank note B moves out of the suction zone S in accordance with the rotation of the rotatable cylinder 5, while it is turning over the bank note 1. Afterward. the next suction tube 6 comes into the suction zone S. Then, is similarly, the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected by the pressure sensor 18 increases first and the pressure in the suction passage 11 and the interior of the hollow shaft 4 begins to fall at the time the suction opening 7 of the next suction tube 6 comes to face the surface of the top bank note 1 and sucks the bank note B. In this manner. as shown in Figures 4 and 5, the change in pressure in the suction passage 11 and' the interior of the hollow shaft 4 is repeated every time the suction opening 7 of the suction tube 6 sucks and turns over one bank note B in accordance with the rotation of the rotatable cylinder 5. In Figures 4 and 5. the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected when second and following bank notes are sucked 21 is seen to be higher than that detected when the first bank note B is sucked. This is because the sucking and turning over operations of the bank notes by the suction opening 7 of the suction tube 6 are successively repeated at short intervals and, therefore, the pressure in the suction passage 11 and the interior of the hollow shaft 4 does not have time to fall so far in the sucking and turning over operation of the first bank note B. In this manner. the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected by the pressure sensor 18 fluctuates every time the suction opening 7 of the suction tube 6 sucks and turns over one bank note B. The counting means 29 monitors the pressure signal input from the pressure signal output meant 25 and counts bank notes B in such a manner that one bank note 1 is counted every time the sign of the rate of change of the pressure signal changes from minus to plus. Every time the counting means 29 counts a bank note B, it outputs the counting signal to the display means 35, thereby to cause it to display the count value of the bank notes B. In Figures 4 and 5, D indicates the range in which the number of bank notes 1 was counted.

Thus, when the bank notes B have been successively sucked and turned over one by one by the suction opening 7 of the suction tube 6 in accordance with the rotation of the rotatable cylinder 5 and, as a result. when the comparing means 31 detects-that the number N of-the bank notes B counted by the counting means 29 has become equal to the set number Not it outputs a coincidence signal to the motor 22 control means 2-7 and the first brake signal output means 33.

Figure 6 shows an enlarged view of the pressure curve of Figure 4 after the number Rof the counted bank notes B has come near the set number No. In Figure 6, E shows the time at which the coincidence signal was output.

When the motor control means receives the coincidence signal from the comparing means 31, it stops the operation of the motor 8. However, since the rotatable cylinder 5 continues to rotate, the next bank note B is sucked and turned over from the holder 2 by the suction opening 7 of the next suction tube 6.

On the other hand, when the first brake signal output means 33 judges based upon the bank note detection signal input from the counting means that the number N of the bank is notes B sucked and turned over has become equal to (NO + 1), it outputs the first brake signal to the motor control means 27 and the second brake signal output means 32 and a count stop signal to the counting means 29. In Figure 6, E shows the time at which"the coincidence signal was output and F shows the time at which the first brake signal and the count stop signal were output.

-Figure 7 is a schematic drawing showing a plan view of the rotatable cylinder 5 when the first brake signal and the count stop signal are output from the first brake signal output means 33. BNo designates the Noth bank note Br BNo+1 designates the (NO + 1)th.bank note B and BNo+2 designates the (NO +2)th bank note B. When the motor control means 27 receives the first 23.

k brake signal from the first brake signal output means 33, it outputs a forward rotation signal and a reverse rotation signal to the motor 8 simultaneously, thereby to force the rotation of the rotatable cylinder 5 to stop. When the counting means 29 receives the count stop signal, it does not count the (NO + 1)th bank note B..

On the other hand, when th e second brake signal output means-32 receives the first brake signal from the first brake signal output means 33, it starts monitoring the pressure signals output from the pressure signal output means 25.

Thus, since the forward rotation signal and the reverse rotation signal were simultaneously output from the motor control means 27 to the motor 8, the rotatable cylin- is der 5 is stopped at the position indicated in Figure 8.

Under these circumstances, the Noth bank note B is superposed on the stack of bank notes B consisting of first to (NO + 1)th bank notes B and a stack of NO bank notes B is formed. 20 At this time, since the suction tube 6 which sucked it has moved out of the suction zone S. the (NO + 1)th bank notes B is not sucked by the suction tube 6. However, since the suction tube 6 sucking the (NO + 2)th bank notes B is positioned in the suction zone S, the pressure in the hollow shaft 4 and the suction passage 11 is kept at a low value. Then, the second brake signal output means 32 outputs a reverse rotation signal to the.motor control means 27 thereby to drive the motor 8 and reversely rotate the ro- 24 91 k tatable cylinder 5. The timing at which the reverse rotation signal is output is experimentally determined so that it is output when a predetermined time period has passed after the second brake signal output means 32 received the first brake signal from the first brake signal output means 33. In Figure 6, G shows the time at-which the reverse rotation signal was output.

is Even.if the rotatable cylinder 5 is reversely rotated in this manner, since the (NO + 1)th bank notes B has not be sucked by the suction opening 7 of the suction tube 6, when the suction tube 6 which sucked the (NO + 1)th bank notes B cbmes into the suction zone S, air flows into the suction passage 11 from the suction opening 7 via the interior of the shaft 10 of the suction tube 6, the communicating passage 14 and the interior of the hollow shaft 4 and, therefore, the pressure in the suction passage 11 and the hollow shaft 4 increases. The second brake signal output means 32 monitors the pressure signals input from the pressure signal output means 25 and outputs a reverse rotation stop signal to the motor control means 27 and a pump stop signal to the pump motor control means 24 immediately after the level of the pressure signal begins to 'increase, whereby the operation of the motor 8 and the pump motor 13 are stopped. In Figure 6, H designates the time at which the reverse rotation stop signal and the pump stop signal were output.

As a result. the rotatable cylinder 5 continues to rotate by its inertia,, while the pressure in the suction passage 11 and the hollow shaft. 4 detected by the pressure k sensor 18 increases.

The second brake signal output means 32 monitors the pressure signal input from the pressure signal output means 25 and outputs a second brake signal to the motor control means 27 at a predetermined timing, thereby to cause it to output the forward rotation signal and the reverse rotation signal to the motor simultaneously and to force the rotatable cylinder 5 to stop.. This timing at which the second brake signal is output is experimentally determined so that if the second brake signal is output at the timing, the suction opening 7 of the suction tube 6 which sucked the (NO + 1)th bank notes B returns the (NO + 1)th bank notes B is to the holder 2 and is stopped at the position where it faces the surface of the (NO + 1)th bank notes B, that is, the surface of the holding plate 2a of the holder 2. This timing is stored in the second brake signal output means 32. In Figure 6, J shows the time at which the second brake signal was output.

As described above, the stack o f NO bank notes B is separated and is collected in a known manner from the bank note counting machine 1. Simultaneously, since the suction opening 7 of one suction tube 6 is always stopped so as to face the surface of the (NO + 1)th bank note B which is the top bank note B held in the holder 2. it becomes possible to suck and turn over the top bank note B without fail when the next counting operation is started. Further, in the same manner, the stack of NO bank notes B is separated and collected.

26 1 1 Figure 9 shows an enlarged view of the pressure curve of Figure 5 after the number N of the counted bank notes B has come near the set number No. Figure 7 shows the pressure curve obtained in the case where the number of bank notes B set in the holder 2 is equal to (NO + 1)i while Figure 6 shows the pressure curve obtained in the case where the number of bank notes B set in the holder is not less than (NO + 2).

In this case, when the comparing means 31 judges that the number N of the counted bank notes B becomes equal to the set number NO, the coincidence signal is output and the motor 8 is stopped by the motor control means 27. Then, when the first brake signal output means 33 judges based upon the bank note detection signal input from the counting means 29 is that the (NO + 1)th bank note B has been detected, it outputs-the first brake signal. In Figure 9, E shows the time at which the first brake signal was output and F shows the time at which the first brake signal and the count stop signal were output.

Afterward, similarly to the case shown in Figure 6, although the reverse rotation signal is output from the second brake signal output means 32 and the rotatable cylinder 5 is reversely rotated, since the (NO + 2)th bank note B is not present in the holder 2, no suction opening 7 of the suction tube 6 sucks a bank note B at the time the first brake signal is output. Therefore. air flows into the suction passage 11 from the suction opening 7 of the suction tube positioned within the suction zone S via the interior 27 of the shaft 1D of the suction thbe 6, the communicating passage 14 and the interior of the hollow shaft 401 whereby the pressure in the suction passage ll'and the hollow shaft 4 detected by the pressure sensor 18 increases. However, since the angle between the radial lines % and % is determined smaller than 72 degrees, which is the angle between the adjacent suction tubes 6, it can occur that no suction tube 6 is positioned within the suction zone S in accordance with the reverse rotation of the rotatable cylinder 5. As a result, the pressure in the suction passage 11 and the hollow shaft 4 falls again. Then, when the suction tube 6 which sucked the -(NO + 2) th bank note B comes into the suction zone S, air flows again into the suction passage 11 from the suction opening 7 via the interior of the shaft 10 is of the suction tube 6. the communicating passage 14 and the interior of the hollow shaft 4 and the pressure in the suction passage 1 and the hollow shaft 4 which fell once increases again. The second brake signal output means 32 monitors the pressure signals i nput from the pressure signal output means 25 and outputs a reverse rotation stop signal to the motor control means 27 and a pump stop signal to the pump motor control means 24 immediately after it detects that the pressure in the suction passage 11 and the hollow shaft 4 which had fallen once has begun to increase. As a result. the motor 8 and the pump motor 13 are stopped. In Figure 9, G shows the time at which the reverse rotation signal was.output and H shows the time at which the reverse rotation stop signal and the pump stop signal were output.

28 k Accordingly, similarly to the case shown in Figure 6, the rotatable cylinder 5 continues to rotate by its inertia, while the pressure in the suction passage 11 and the hollow shaft 4 detected by the pressure sensor 18 increases.

The second brake signal output means 32 monitors the pressure signals input from the pressure signal output means and outputs the second brake'signal.to the motor control means 27 at a predetermined timing, thereby to cause it to output the. forward rotation signal and the reverse rotatio n signal to the motor 8 simultaneously and force the rotatable cylinder 5 to stop. This timing at which the second brake signal is output is experimentally determined so that if the second brake signal is output at the timing, the suction opening 7 of the suction tube 6 which sucked the (NO + 1)th bank note B returns the (NO + 1)th bank note B to the holder 2 and is stopped at the position where it faces the surface of the (NO + 1)th bank note B, that is, the surface of the holding plate 2a of the holder 2. This.timing is stored in the second brake signal output means 32. In Figure 9, j shows the time at which the second brake signal was output.

As described above, the stack of NO bank notes B is separated and is collected in a known manner from the bank note counting machine 1. Simultaneously, since the suction opening 7 of one suction Eube 6 is always stopped so as to face the surface of the top bank note B set in the holder 2 at the next counting operation. it becomes possible to suck and turn over the top bank note B without fail when the next counting operation is started.

29 Figure 10-shows an enlarged view of the pressure curve obtained in the case where the number of bank notes B set in the holder 2 is equal to NO and shows the pressure curve after the number N of the counted bank notes B has come near the set number No.

in Figure 10, when the Noth bank note B has been sucked and turned over by the suction opening 7 of the suction tube 6, the sign of the rate of change of the pressure signal input.from the pressure signal output means 25 changes from minus to plus and the counting means 29 counts the Noth bank note B by detecting this change. Then, since no bank note B to be sucked by the suction tube 6 is present, the level of the pressure signal output from the pressure signal output means 25 increases to higher than the maximum level detected in the range D where the counting operation was being carried out.

When the counting completion signal output means 34 detects that the level of the pressure signal input from the pressure signal output means 25 has increased to not less than a predetermined level, itoutputs a counting completion signal to the first brake signal output means 33. thereby to prevent it from outputting the first brake signal and the counting stop signal and cause it to output a pump stop signal to the pump motor control means 24. As a result, the operation of the vacuum pump 12 is stopped by the pump motor 13. Further, when the counting completion signal is input, the first brake signal output means 33 starts monitoring the pressure signal input from the pressure signal output means 25. Although the counting completion signal output means 34 simultaneously outputs the counting completion signal to the comparing means 31, the comparing means 31 does not output any signal when it has output the coincidence signal before the counting completion signal is input.

Although the operation of the motor 8 is stopped at the time the coincidence signal is input to the motor control means 27 from the comparing means 31, since the rotatable cylinder 5 continues to rotate counterclockwise in Figure 1 about the shaft 4 by inertia even after the operation of the motor 8 is stopped, the next suction tube 6 comes into the suction zone S. On the other hand, at the time the counting completion signal is input to the pump motor control means 24 from the counting completion signal output means 32, since the operation of the pump motor 13 is stopped so that vacuum pressure is no more applied to the suction passage 11 and the interior of the hollow shaft 4 from the vacuum pump 12 and there is no bank note B to be sucked by the suction opening 7 of the next suction tube 6, if the next suction tube 6 has come into the suction zone S. air flows into the inside of the hollow shaft 10 through the suction opening 7 of the suction tube 6 and. further, flows into the suction passage 11 through the communicating passage 14 and the interior of the hollow shaft 4. Under these conditions, since the rotatable cylinder 5 continues to rotate by its inertia, the pressure in the suction passage 11 and the interior of the hollow shaft 4 detected by the pressure sensor 18 fluctuates so as to produce peaks as 31 A shown in Figure-10.

The first brake signal output means 33 monitors the pressure signal input from the pressure signal output means 25 and outputs a third brake signal to the motor control means 27 at a predetermined timing. When the motor control means 27 receives the third brake signal from the first brake signal output means 30, itoutputs a forward rotation signal and a reverse rotation signal to the motor 8 simultaneously, thereby to cause the motor to force the rotatable cylinder 5 to stop. The predetermined timing at which the first brake signal output means 33 outputs the third brake signal is determined such that if it outputs the third brake signal to the motor control means 27 at the timing, the suction opening 7 of the suction tube 6 after next is stopped at the position at which its suction opening 7 faces the surface of the holding plate 2a of the holder 2 positioned at its counting position. Thus, it is ensured that when the next counting operation is started, the suction opening 7 of one suction tube 6 faces the top bank note B and sucks and turns over it without fail for enabling the machine to accurately count the bank notes B. Such timing can be easily determined by experiments. Further.. even if the timing experimentally determined f or outputting the brake signal is inappropriate, it is easy to automatically correct the timing for outputting the brake signal so to be appropriate after one counting operation of bank notes B has been comple. ted and to output the brake signals at the correct timing in the next and following bank 32 i i k note counting operations. Moreover, since it-is ensured by the positioning control means that the counting operation of bank notes B is started in the condition where the suction opening 7 of a suction tube 6 faces the surface of the top bank note B, even if the timing experimentally determined for outputting the brake signal is inappropriate, it is still possible to accurately count the number of bank notes B. In Figure 10, K shows the time at which the pump stop signal was. output. L shows the time at which the third brake signal was output and M shows the time at which the rotatable cylinder 5 was stopped as a result of outputting the third brake signal.

Further, in the case where the number N of the bank notes B set in the holder 2 is less than the set number No. since the pressure signal level monitored by the counting completion signal output means 34 increases to a level higher than a predetermined level after the last bank note B has been counted, the counting qompletion signal output means 34 outputs the counting completion signal to the comparing means 31. In such a case, since at the time the comparing means 31 receives the counting completion signal. it has not yet received the counting signal indicating that the Noth bank note B was counted, it therefore has not output the coincidence signal yet, and, therefore, the comparing means 31 outputs the counting completion signal to the display means 35, thereby to cause it to display that the counting operation has been completed before the Noth bank note B is counted.

33 1 1 k C:

As described above, in the case where the number of bank notes B set in the holder 2 is greater than the set numbe. r NO, since the first brake signal is output from the first brake signal output means 33 so that when the rotation of the rotatable cylinder 5 is stopped, the set number Noth bank note B has been superposed on the stack of bank notes consisting of the first to (NO - 1)th bank notes and the stack of NO bank notes has been formed and then after the rotatable cylinder 5 has been reversely rotated, the second brake signal is output so that when the rotation of the rotatable cylinder 5 is stopped, the suction opening 7 of the suction-tube 6 which sucked the (NO + 1)th bank note B faces the surface of the (NO + 1)th bank note B which has been returned-to the holder 2, it becomes possible to separate and collect the stacks of NO bank notes without fail and to reliably suck and turn over the top bank note by the suction opening 7 of the suction tube when the next counting operation is started. In addi tion, it is possible to separate and collect the stack of No bank notes without fail without any special means, only by monitoring the pressure in the suction passage 11 and the hollow tube 4 which has been monitored in the past.

Further. in the case where the number of bank notes B set in the holder 2 is equal to the set number NO, since thesuction opening 7 of the suction tube 6 is automatically positioned so as to face' the surface of the top bank note B to be first sucked at the 34 next counting operation, it becomes possible to suck and turn over the top bank note B without fail when the next counting operation is started, thereby to accurately count the bank notes B. As described in.-detail.,. it is possi- ble to provide a sheet counting machine capable of reliably separating. and collecting stacks of a predetermined number of sheets with a simple structure.

In the above. though explanation is made for a bank note counting machine, the present invention can be applied to a counting machine for counting printed sheets such as public lottery tickets, slips and the like and,-further., to a counting machine for counting non-printed sheets. In the case of a counting machine for counting non-printed sheets, since it is unnecessary to discriminate among the sheets. the light emitter 16 and the light receiv er.17 can be omitted.

Further, in the above, although five suction tubes 6 are provided so as to be spaced from al- 1 1 15.

each other by 12 degrees around the shaft 4 and located at the same distance from the shaft 4, the number of the suction tubes 6 is not limited to five. However, since if two or more suction tubes 6 come to be positioned within the suction zone S. it becomes impossible to count the number of sheets. the angle between adjacent suction tubes 6 with respect to the circumference -of the rotatable cylinder 5 has to be greater than the angle between the radial lines xa and % and since if the angle between adjacent suction tubes 6 is-too small, there arises some risk of interference between sheets sucked by the adjacent suction tubes 6, it is preferable that not more than eight, and more preferable that four to six suction tubes 6, be arranged so as to be equiangularly spaced from each other around the shaft 4 and be located at the same distance from the shaft 4.

Furthermore, in the abovet al- though the first brake signal output means 33 outputs the first brake signal when the counting means 29 has detected the (NO + 1)th bank note B and the.bank note detection signal is output, the first brake signal may be output at such a timing that when the rotatable cylinder 5 is stopped, the Noth bank note B has been superposed on the stack consisting of the first to (NO - 1)th bank notes B and the stack of No bank notes B has been formed and the Noth bank note B cannot be sucked by the suction opening 7 of the suction tube 6 and returned to the holder 2, even if the rotatable cylinder 5 is reversely rotated, and the first brake signal may be output based upon the pressure signal 36 4 output from the- pressure signal output means 25 by causing the first signal output means 33 to monitor the pressure signal.

Moreover, in the above, in th e case where the NO bank notes B are set in the holder 2.

although the counting completion signal output means 34 is provided and the first brake signal output means 33 is prevented from outputting the first brake signal and the count stop signal when the counting completion signal is input from the counting completion signal output means 34, thereby to prevent the rotatable cylinder 5 from being reversely rotated,it is possible to reversely rotate the rotatable cylinder 5 and to position the suction opening 7 of one suction tube 6 so as to face the surface of the is holding plate 2a of the holder 2 positioned at its counting position by causing the first brake signal output means 33 to monitor the pressure signals output from the pressure signal output means 25 and output only the first brake signal without outputting the count stop signal when the 20' first brake signal output means 33 detects that the level of the pressure signal has become higher than the predetermined level.

In addition, in the above, al- though the communicating passage 14 is formed so as to communicate the interior of the shaft 10 of the suction tube 6 with the interior of the hollow shaft 4 and the suction passage 11 only when the center of the suction tube 6 is positioned within the suction area S, it is possible to 37 1 communicate the-interior of the shaft 10 of the suction tube 6 with the interior of the hollow shaft 4 and the suction passage 11 via the communicating passage 14 only when the whole of a suction tube 6 is positioned within the suction zone S by appropriately determining the range of the suction zone S.

Furthermore, in the abovet al- though when the first brake signal is input from the first brake signal output means 33 or when the second brake signal is input from the second brake signal output means 32, the motor control means 27 electrically forces the motor to stop, a mechanical brake means may be provided so that when the first or second brake signal is input, the motor control means 27 actuates the mechanical brake means, thereby to is force the rotatable cylinder 5.to stop.

Further, in the above, although the pressure sensor 18 detects the pressure in the suction passage 11, it may detect the pressure in the interior of the hollow shaft 4.

Furthermore, in the above, aI- though each suction tube 6 is formed withone suction open ing 7, each suction tube 6 can be formed with a plurality of suction opening 7.

Moreover. in the above. although the predetermined level of the pressure signal is determined for outputting the counting conpletibn signal as an absolute pressure level, it is possible to determine the predetermined pressure level so that it is greater than an average 38 1 pressure level or maximum pressure level detected during the counting by a predetermined amount.

Further. the respective means need not necessarily.bekphysj4-cal means and arrange- ments whereby the functions of the respective means are accomplished by software fall within the scope of the present invention. In addition, the function of a single means'may be accomplished by two or more physical means and the functions of two or more means may be accomplished by a 10 single physical means.

is 39 1

Claims (9)

Claims;

1. A sheet counting machine comprising a sheet holder for holding sheets to be counted, a rotatable cylinder rotatable about a hollow shaft, motor mea ns for rotating the rotatable cylinder, motor control means for controlling the operation of the motor means, a plurality of suction tubes projectingly formed on one end face of the rotatable cylinder so as to be equiangularly spaced from each other around the hollow shaft and be located at the same distance from the hollow shaft, each of the suction tubes having at least one suction opening, vacuum pump means for applying vacuum pressure to the hollow shaft, vacuum pump control means for controlling the operation of the vacuum pump means, communicating means arranged so as to communicate only the suction tube positioned within a-predetermined zone in which it faces sheets held by the sheet holder among the plurality of suction tubes with the inside of the hollow shaft, pressure detecting means for detecting changes in pressure in the hollow shaft produced by sucking and turning over the sheets held by the sheet holder by the vacuum pressure applied from the vacuum pump means, counting means for counting the number of sheets based upon the changes in pressure in the hollow shaft.detected by the pressure detecting means, sheet number setting means for setting the number NO of sheets to be separated and collected, and comparing means for judging whether or not the number of counted sheets coincides with the set number NO set by the sheet number setting means based upon the output from the counting means and, when 1 i judging they cc4incide with each other, outputting a coinci dence signal to the motor control means, thereby to cause the motor control means to stop the operation of the motor means, the sheet counting machine being characterized in that there are provided first brake signal output means for outputting., after receiving the coincidence signal output is from the comparing means, based upon the pressure in the hollow shaft detected by the pressure detecting means, a first brake signal to the motor control means so as to force the rotatable cylinder to stop at a timing so that the rotatable cylinder is stopped at a position where a Noth sheet is superposed on a sheet stack consisting of first to (NO -1)th sheets.so as to form a stack of NO sheets and where even if the rotatable cylinder is reversely.rotated afterward, the suction opening- of the. suction tube having sucked the Noth sheet cannot suck the Noth sheet, and second brake signal output means for receiving the first brake signal, outputting a reverse rotation signal to the motor control means so as to reversely rotate the rotatable cylin20 der after the rotatable cylinder has been stopped, outputting, based upon the change in pressure in the hollow shaft detected by the pressure detecting means, a reverse rotation stop signal to the motor control means so as to stop the reverse rotation of the rotatable cylinder and a drive stop signal to the vacuum pump control means so as to stop the supply of vacuum pressure to the interior of the hollow shaft from the vacuum pump means at a predetermined timing. and outputting a second brake signal to the motor control 41 1 means at a timing so that the rotatable cylinder is stopped at a position where all of the at least one suction opening of one suction tube among the plurality of suction tubes face the surface of the sheet holder.

2. A sheet counting machine in accordance with Claim 1 wherein the sheet counting machine f urther comprises counting completion signal output means for monitoring the pressure in the hollow shaft detected-by the pressure detecting means and outputting a counting completion signal to the first brake signal output means when the pressure in the hollow shaft increases to not more than a first predetermined value after the counting means has started counting sheets so as to prevent the first brake signal output means from outputting the first brake signal and cause the first brake signal output means to output a drive stop signal to the vacuum pump control means and start monitoring the pressure in the hollow shaft input from the pressure detecting means, and is constituted so that when the first brake signal output means receives the counting completion signal from the counting completion signal output means, it outputs, based upon the change in pressure in the hollow shaft detected by the pressure detecting means, a third brake signal to the motor control means at a predetermined timing so as to cause the motor means to force the rotatable cylinder to stop at a position where all of the at least one of suction opening of one suction tube among the plurality of suction tubes face the surface of the sheet holder.

3. A sheet counting machine in accordance with Claim 1 or 42 a 2 wherein not more than eight suction tubes are provided.

4. A sheet counting machine in accordance with any one of Claims 1 to 3 wherein four to six suction tubes are provided.

5. A sheet counting machine in accordance with any one of Claims 1 to 4 wherein the vacuum pump means is adapted for applying vacuum pressure to the interior of the hollow shaft via a suction passage.

6. A sheet counting means in accordance with any one of Claims 1 to 5 wherein there are further provided counting start signal output means for monitoring the changes in pessure in the interior of the hollow-shaft detected by the pressure detecting means, outputting a counting start signal to the counting means when it detects that the absolute value of the rate of change of the pressure monitored is not less than a third predetermined value and that the pressure has fallen not-more than the first predetermined value and outputting a positioning signal when the absolute value of the rate of change of the pressure monitored is less than a third predetermined value and when it detects that the absolute value of the rate of-change of the pressure moni- tored is not less.than a third predetermined value and that the pressure has fallen not more than the first predeter- mined value after outputting the positioning signal, output- ting the counting start signal to 'the counting means, and positioning control means for outputting, when it receives the positioning signal from the counting start signal output means, a reverse rotation signal to the motor control means, 43 1 thereby to cause the motor means to rotate the rotatable cylinder reversely, monitoring the pressure in the interior of the hollow shaft detected by the pressure detecting means and outputting, when it detects that the absolutevalue of the rate of change of the pressure monitored has increased to not less than the third predetermined value, a reverse rotation stop signal to the motor control means, thereby to cause the motor means to stop the reverse rotation of the rotatable cylinder.

7.. A sheet counting machine in accordance with any one of Claims 1 to 6 wherein th ere are provided light emitting means for emitting light onto the surface of a sheet held by the sheet holder positioned at its counting position and light receiving means for receiving light reflected by the surface of the sheet.

8. A sheet counting machine in accordance with any one of Claims 1 to 9 wherein the sheets are bank notes.

9. -A sheet counting machine substantially as herein described with reference to and as shown in the accompanying drawings.

44 Published 1991 atThe P&tcntoffke. state House. 66171 High Holborn. London WC1 R 47P. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point Cwm(clinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid, St Mary Cray. Kent.

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