Money-operated unit control system

Claim 1

A central control panel to be used in association with a source of electric power, defining at least two power terminals, and a plurality of electrical units, each such unit including a unit controller device operable to control the functioning of the unit upon delivery of a start signal to the unit controller device, the start signal being a signal from a pre-determined terminal of the power source, wherein the control panel comprises: a power input means connectable to a first power terminal of the power source; a plurality of electrical switch means, each such switch means defining two normally closed switches and a normally open switch, each switch defining two terminals, the three switches being ganged together for simultaneous operation, one of the normally closed switches of each switch means being connected in a first series to each corresponding normally closed switch and to the power input means, another of the normally closed switches of each switch means being connected in a second series with each corresponding another normally closed switch, a first terminal of each normally open switch being connected to an electrical unit controller device, a second terminal of each normally open switch being connected with a terminal of the said another normally closed switch within the same switch means, and, a control relay means, including an energizing circuit and a normally open relay switch, the energizing circuit being connected in series to the normally closed switch of a last switch means in the said first series, the energizing circuit being connectable to the second power terminal of the power source, whereby a voltage difference may be defined across the energizing circuit, the relay switch being connectable between the pre-determined terminal of the power source and the normally closed switch of the first switch means in the said second series.