Patent GB-1272560-A (GB)
Title: Coin selector for determining the authenticity and denomination of coins
Inventor: FOUGERE GUY LLOYD
IPC: G07D5/00
Filed: 1970-04-01
Abstract: 1,272,560. Testing coins. MARS Inc. 1 April, 1970 [1 April, 1969], No. 15476/70. Heading G4V. Coins move down a passageway across which a magnetic field acts, the velocity of each coin after passing through the magnetic field is sensed and compared by means of a circuit with a predetermined value representing the velocity an acceptable coin would have, and a chordal dimension of each coin is sensed and compared with a corresponding acceptable value. The device for testing coin authenticity in this way may be capable of testing several coins of different denominations and of sensing their denominations for actuating a counter accordingly. Means may also be provided for preventing coins of highly magnetic material from entering the testing part of the device. The device shown is adapted for use with a coin operated machine accepting three denominations of coin, valued at one, two and five units, respectively. Magnetic coin scavenging.-Initially each coin is held by a stop 18 at the top of a ramp 16, where it occludes a photo-electric sensor 21 which triggers four multivibrators 52, 54, 56, 58, set to change state in sequence. 52 changes first to remove stop 18. When the coin should have rolled clear of a scavenger 20, in the form of a pivotally mounted permanent magnet 54 changes. If the coin has not rolled clear, signals from 54 and 21 trigger AND 62 to actuate an electromagnet 28 to pivot the scavenger magnet and reject the coin. Just before the fastest coin to be accepted should have reached a second sensor 64, 56 changes to reset the apparatus for the next coin. Shortly after the slowest coin to be accepted should have reached sensor 64, 58 changes so that, if the coin is too slow or has jammed, means 70 is actuated to prevent subsequent counting of the coin. Measuring retardation of coin by magnetic field.-If the coin reaches sensor 64 within the expected time range, flip-flop 74 is set to enable AND 80. Pulses from a clock 76 are then counted at 78 until the coin occludes a third sensor 65 to reset flip-flop 74. The time taken between 64 and 65 is proportional to the number of pulses counted. This count is fed to a known device 83 which inverts the count and applies a division rate determined by reference to the magnitude of the count. The output from 83 serves as a clock 84 for the remainder of the coin analysing operation. The actual velocity of the coin between 64 and 65 is thus rendered immaterial, so that tipping the machine to increase the velocity of a counterfeit coin will not prevent recognition of the counterfeit. After passing through the magnetic field at 23, the coin successively occludes fourth and fifth sensors 66, 67 which through flip-flop 86 enable AND 88 for a number of pulses proportional to the time taken between 66 and 67 to pass from clock 84 to counter 90. These pulses are fed to a decoder 94. Three flip-flops 98, 100, 102 are chosen so that they will be set and reset by counts representative of the lower and upper acceptable limits respectively for the one, two and five unit coins respectively. Consequently one of these flip-flops will be set, but not reset, if an acceptable coin is sensed. Measuring chordal dimension.-When the coin begins to occlude sensor 67, flip-flops 104, 106 clear counter 90. As long as sensor 67 is occluded, AND 108 is enabled so that a number of pulses proportional to the chordal dimension are fed from clock 84 to counter 90. The count passes to decoder 110 to set, but not reset, one of three flip-flops 112, 114, 116, which operate for upper and lower dimension counts in the same way as 98, 100, 102 did for velocity counts. Acting upon the measurements.-Corresponding flip-flops 98 and 112, 100 and 114, 102 and 116 gate three respective AND gates 118, 120, 122. If the coin was one of the three acceptable denominations, the corresponding one of these three AND gates will be enabled and through OR 124 will operate a solenoid 25 to pivot a gate (24), Fig. 3 (not shown) and allow the coin to fall into an acceptance passage (26). If not pivoted, the gate will divert an unacceptable coin into a rejection passage (27). Actuating counter according to denominations of coins tendered.-If the coin did not become jammed, means 70 as described above would not have been actuated, so AND 138 is enabled to allow pulses through OR 136 to a counter 132. If AND 118 (corresponding to the one unit coin) has been enabled, one pulse is sent through OR 136 to the counter. If AND 120 (two units) or AND 122 (five units) has been enabled, flip-flops 140 or 149 respectively are set to enable AND 142 or AND 150 respectively to pass pulses from the clock 76 to counter 132 and a second counter 134. Decoders 146, 147, responsive to counter 134 reset flip-flops 140, 149 respectively after two or five pulses respectively have been passed. Modifications.-The velocity of the coin before the magnetic field is not sensed, in which case a circuit produces out of phase A and B pulses. The A pulses are fed to a counter equivalent to counter 90 when a flip-flop equivalent to flip-flop 86 is set, and a decoder is triggered by the B pulses to read the counter between successive A pulses. Four sensors are used to measure the chord dimension and their spacing corresponds to acceptable coin sizes so that two must be occluded simultaneously for acceptance. High and low voltage gating signals are used to reject oversize coins. Alternatively seven chord dimension sensors may be used. Six of these are arranged in three pairs corresponding to minimum and maximum acceptable dimensions for the three respective coins, and the seventh is a master sensor. For acceptance, the master sensor and the respective minimum dimension sensor must be occluded simultaneously without the respective maximum dimension sensor being occluded.