Patent GB-1430016-A (GB)
Title: Control circuits for coin-controlled vending machines
IPC: G07F5/22
Filed: 1973-04-11
Abstract: 1430016 Coin-freed vending machines H R ELECTRONICS CO 11 April 1973 [29 June 1972] 17359/73 Heading G4V A control circuit for a coin-operated vending machine comprises a reversible binary counter 10 for accumulating the value of coins deposited, means 40 for determining when the vend price has been reached to initiate a vend operation and simultaneously reset the counter, further inputs to the counter being accumulated to establish the amount of change due, means for refunding change and means for applying debit inputs to the counter as the change is refunded. The embodiment described accepts 5c., 10c. and 25c. coins, these operating respective switches 21, 23, 25 to apply a signal to pulse generator 12 and cause it to input one, two or five pulses into the counter 10 appropriately. Each stage of the counter 10 has two outputs, and the setting of switches 44 to 50, one for each pair of outputs, determining the vend price. When sufficient credit is established vend gate 40 sets flip-flops 52, 54 to operate a vend relay 68 via a NAND gate 60 and to reset the counter via a reset circuit 84 to 92. This circuit also resets the counter when there is a severe line voltage fluctuation or when the circuit is switched on. The other input to the NAND gate 60 is from a delay circuit 62 to 66 which ensures a sufficiently prolonged operation of the vend relay. Change giving.-If the amount inserted equals the vend price then after a delay provided by circuit 62 to 66, NAND gate 72 will produce a signal to reset flip-flops 52, 54 and prepare the circuit for another operation. If the amount exceeds the vend price further pulses are accumulated in the counter and gate 72 is not operated to produce the reset signal, and high signals from inverter 70 are therefore applied to refund NAND gates 100 and 110. The arrangement is such that if both refund relays 98, 108 are operated a 10c. coin is dispensed and if only relay 98 is operated a 5c. coin is dispensed. The second input to NAND gate 100 is from a circuit detecting whether any of the coin switches is shorted and the second input to NAND gate 110 from a circuit, including NAND gate 114, which determines if a 5c. coin is to be refunded. After the refund of a 5c. coin, if necessary, the remaining change is paid in 10c. coins, respective signals A, B from a circuit 126 to 136 being applied to the pulse generator for each coin refunded. On operation of the refund mechanism switch 34 is changed over to set the counter to its subtract mode, the pulses from the generator debiting the counter until no more change is required. A switch 120 opens when the supply of 10c. change coins is depleted, the change then being paid all in 5c. coins. The circuit may be modified by making the dotted line connections to pay change in 5c. and 25c. coins, the gates 114, 116 and 140 detecting whether the change required is greater than 25c. Coin return.-The customer may operate an escrow switch 148 at any time before sufficient credit is established, closure of the switch setting flip-flop 54 and conditioning the gates 100, 110 to enable a refund to be made by payment of change coins rather than those actually deposited.