Patent GB-1414804-A (GB)
Title: Control circuit for use in a vending machine
IPC: G07F5/18
Filed: 1972-11-21
Abstract: 1414804 Vending machines OAK INDUSTRIES Inc 21 Nov 1972 [23 Feb 1972] 53676/72 Heading G4V A vending machine comprises a coin receiving means 14, commodity selection switches 30, electrically operating dispersing means 36 and a control circuit, said circuit including switch means 10 placed in an "on" condition when power is supplied to the machine to enable the receiving means 14 to accept coins and a memory 18 activated when sufficient coins have been received to place a power switch 22 in an "on" condition, said switch means 10 being placed in an "off" condition when the power switch 22 is placed in an "on" condition. In the embodiment shown the coin reception enabling switch comprises SCR 124 in circuit with an electromagnet 116 of the coin receiving means, the SCR124 being triggered into conduction during alternate half cycles of the A.C. source applied on lines 70, 72. When sufficient coins have been inserted a switch 126 in the coin receiving means is closed, triggering an SCR 84 conductive. A capacitor 90 (comprising the memory) is charged and functions to alternately trigger SCRs 82, 84 (comprising the power switch) into conduction during alternate half cycles of the applied A.C. Capacitor 140 charges and biases neon lamp 138 to prevent triggering of SCR 124 during the next half cycle, thus de-energizing electromagnet 116 and reject any further coins deposited. Conduction of SCRs 82, 84 establishes a potential at the junction of resistors 146, 148 which is applied to commodity selection switches 30a to 30f. The closure of one of the switches triggers a corresponding SCR 46 of a solenoid power switch into conduction and hence energizes a dispensing solenoid 36a to 36f, providing the respective sold out switch 62 is closed; and the current flowing the resistor 160 applies a potential to raise all the other solenoid switches above ground and prevent them being triggered. The potential across resistor 160 also charges capacitor 152 which enables the triggering of SCR 124 and hence the discharge of memory capacitor 90 and the turning off of SCRs 82, 84. If a selection is not made after a predetermined time the potential built up across capacitor 104 becomes sufficient to ionize neon lamp 106 and trigger SCR 124 to reset the machine to a standby condition. In another embodiment (Figs. 3 and 4, not shown) the coin reception enabling means comprises an SCR (270) which on closure of a credit switch (240) by the deposition of coins is rendered non-conductive and hence de-energizes coil (238) to return any further coins deposited. A memory capacitor (266) is charged on closure of switch (240) causing the triggering of SCR (252) and hence the main power switch triac (228). When one of the commodity selection switches (188a) to (188f) is closed a triac (222) of the corresponding secondary power switch is triggered to initiate the vend and an SCR (310) is triggered to reduce the potential applied to the selection switches, preventing a further selection, and to discharge memory capacitor (266). On discharge of this capacitor the main power switch (228) is turned off and SCR (270) is triggered to energize coil (238) and prepare the machine for the next transaction. A further embodiment (Figs. 5 and 6, not shown) is similar to that of Figs. 1 and 2 except that energization of coil 116 is controlled by diodes (120), (144) the SCR 124 merely serving as part of the reset means of the timing circuit.