GB1489657A - Vending and like machines - Google Patents

Abstract

1489657 Control circuit for vending machine HR ELECTRONICS CO 27 Jan 1975 [25 April 1974] 3408/75 Heading G4V [Also in Division G3] The invention concerns the control circuitry of a coin operated vending machine. An adder circuit (Fig. 2) is employed which receives at B inputs logic signals representing which of a number of articles have been selected to be purchased and delivers at its output a logic signal which causes a selected article to be delivered and change to be given. The output of the added is returned to its input and it is stated that the adder performs a sequence of adding operations in response to the input which eventually results in only one of outputs S 2 -S 4 being set so that only one article is delivered despite more than one of the article selecting switches 144-147 being operated. In Fig. 1 an accumulator 30 adds the total value of coins inerted as detected by switches 24-28. A matrix 54 delivers the price of a selected article. The total credit is compared at 36 with the price and if adequate enables the control circuit 72 (Fig. 2) by input terminal R B . Depending on the amount of excess credit various outputs 60, 62 of the comparator circuit are also enabled to set up the change paying apparatus. Control circuit 72 is enabled and adder 150 adds the selection input to a fixed input at A 1 -A 5 ; after the first addition a carry-out terminal 124 goes to logic 1 and inhibits the selection input so the adder then responds only to its own output. An output on one of the lines S 2 -S 6 energizes through a relay 116-122 a corresponding delivery motor 130-1350 which delivers the selected article. When delivery is detected by interface 134 the control circuit 72 enables an output S 1 to pay out the change selected by comparator 36. The selection interface 74 employs opto-electronic couplers to isolate the control circuitry from the motor supplies (Fig. 17, not shown).