GB721607A - Contact selector driven by a small synchronous motor - Google Patents

Abstract

721,607. Actuation of switches. SAUTER AKT.-GES. FABRIK ELEKTRISCHER APPARATE, F. March 28, 1952, No. 8017/52. Class 38 (5). [Also in Group XXXVIII]. In a selector for the remote control of apparatus by sending two selectively-spaced impulses over a line, a synchronous motor 1 that is started by the first impulse drives two contact arms 12, 12a over two circles of fixed contacts 13, 13a arranged'in two parallel planes and projecting inwards from annular insulating supports 7, 7a. Each circle of fixed contacts is made from a spider-like structure, Fig. 4, stamped out from a sheet of material and then pressed into a frame of synthetic resin moulding mass after which the inner part is stamped out to leave the arrangement of Fig. 3 which shows also terminals 9 connected to the contacts. One of the contacts 8 is longer than the others and forked at its end and the two parts bent outwards to engage the two rings which form part of the contact arm 12, so supplying current to the rings. Each ring has an extension 14 and the extensions are bent inwards to engage the circle of contacts. The two contact arms 12, 12a may be mounted on the same shaft and staggered so that they engage contacts alternately. In the form shown, however, the arm 12 is mounted on a shaft 5 which, by means of a pawl and ratchet mechanism, Fig. 2 (not shown) advances a sleeve 25 one step for each revolution of the shaft 5 and the sleeve 25 carries the arm 12a. The switch 12 thus acts as a "unit" switch and the switch 12a as a " tens " switch. The arms 12, 12a also have associated with them gapped conducting discs 17, 17a engaged during most of a revolution by contacts 15, 16 and 15a, 16a so as to complete the motor circuit. At the end of a revolution the contact 16 enters a gap, and if the parallel contact 16a is also at the end of its revolution and in its gap, the motor will stop. Fig. 7 shows the circuit arrangement. Receipt of a first impulse at 59 closes contacts 61 which complete a circuit from a source 60 to the motor 1 through contact 40 of switch 12. As soon as the motor has started and the contacts 16, 16a have left their gaps, main- 'taining circuits for the motor are established at 15, 16 and 15a, 16a. Circuits to relays 66a, 66b, 66c have been connected to selected contacts of the " unit " and " tens " switches 12, 12a as shown so that to operate any one of these relays it is only necessary to send a second impulse at 59 at a suitable time, i.e. a time when the contact arms 12, 12a are resting on the contacts connected to the particular relay. A circuit is then completed from the source 60 through the contacts 61, switch 12, selected relay 66a back through switch 12a, and the relay is operated.