Patent GB-1401640-A (GB)
Title: Method and apparatus for authenticating and identifying coins
IPC: G07D/
Filed: 1972-10-12
Abstract: 1401640 Testing coins MARS Inc 12 Oct 1973 [12 Oct 1972] 47162/72 Heading G4V A method of testing coins comprises allowing the coin to fall down a coin passageway, generating a travelling magnetic field in the passageway, preferably with a linear motor 50, the field travelling up the passageway, and examining the velocity of the coin subjected to the field. In the embodiment described an inserted coin is brought to rest by retractable gate 15 where it obscures photo-electric sensor 16 and passes between low frequency inductor (30) and reed switch 43 to determine whether it is magnetic (Fig. 4, not shown). Magnetic coins being subjected not to a travelling magnetic field but to a stationary magnetic field. The coin also modifies the current in a high frequency coil (36) in dependence on the coin's resistivity, and a switch 42, both switches 41, 42 or neither of them will be closed to indicate a metallic coin of relatively high resistivity, of relatively low resistivity or a non-metallic coin respectively. The switches 41, 42 and 43 are connected to corresponding flip-flops 104, 106 and 102, which will be set for coins of low resistivity, all metallic coins and magnetic coins respectively. Flip-flop 104 is connected to a controller 144 which selects a high or low current for the linear motor 50 for coins of high or low resistivity respectively. Sensor 16 is connected via a delay device 108 to an activator 110 for withdrawing gate 15. After the coin passes gate 15 it obscures a sensor 11, which while obscured enables gate 134 to pass pulses from a clock 132 into a counter 140, the count level obtained being therefore dependent on a chordal dimension of the coin and its velocity, milled edged coins being slowed by a rack 40. As the coin obscures sensor 12, and provided that the coin is non-magnetic, a flip-flop 154 is set to activate linear motor 50 via device 154 and to enable gate 136 to pass clock pulses into counter 156, the flip-flop 154 being reset as the coin obscures sensor 13. If the coin is magnetic the linear motor will not be activated and the coin on obscuring sensor 17 sets a flip-flop 162 which via a delay device 164 and activator 166 energizes solenoid 60 and enables gate 138 to pass the clock pulses into counter 168, flip-flop 162 being reset as the coin obscures sensor 18. The delay device 164 is provided to avoid significant acceleration of the coin as it approaches solenoid 60. This may alternatively be achieved by shielding the upper end of the solenoid with soft-iron lamellae (64), (66) (Fig. 2, not shown), by arranging the first velocity sensor within the solenoid or arranging that the solenoid is switched on as the sensor 17 is first not obscured after having been obscured by the coin. The sensor 18 provides an enabling signal to decoders 142, 158 and 170 connected to counters 140, 156 and 168 the decoders each providing an output on one of a number of denomination related lines if the count levels correspond to the levels expected for authentic coins of that denomination. Each output line of decoder 158 is connected to gates 148, 149 one of which will be enabled by the signal from flipflop 104 depending on whether the coin is of low or high resistivity. Gates 171, 172 and 173 receive inputs from decoder 142, and gates 148, 149 or decoder 170 and provide inputs to a credit totalizer 178 and OR-gate 174 connected to an actuator 176 for moving gate 70 to a coin acceptance position. Specification 1,319,126 is referred to.