718,379. Control of D. C. motors. C.A.V., Ltd. Oct. 6, 1952, (Oct. 15, 1951], No. 23940/51. Class 38(3) [Also in Group XXV] Electrical door-actuating apparatus comprises a reversible electric motor a, electromagnetically operated switches e, g, for controlling the motor, switches i, j operable by the door at the limits of its travel, and an electromagnetically operated relay, the operating coil o thereof being controlled by manually operated switches p. q, so as to control the operating coils f, h, of the motor controlling switches e. g, the electromagnetically operated relay being provided with a pair of fixed contacts m, k, a movable contact n co-operating therewith, a spring so as to bias the moving contact to the " door opening " position (i.e. contact n co-operating with contact k), energization of the relay operating coil o moving the contact n to the " door-closing " position (i.e. contact n co-operating with contact m), the door operable switch j being moved when the door is closed to complete a circuit so as to maintain the relay operating coil o energized while the door is closed and power is available on the system. As shown in Fig. 1 all switches are in the "door closed" position. Operation of a push button p de-energizes relay operating coil o, thus contact n moves to contact k whereby operating coil f becomes energized to make switch e and the motor a runs to open the door. At the " door fully open " position switches i, j are changed over by the door. If now push button q is operated coil o will be re-energized thus contact n moves to contact m and operating coil h will be energized to make switch g thereby causing the motor to run to close the door. At the "door fully closed " position switches i, j are once more'changed over so completing a retaining circuit for coil o by means of switch j and contacts n, m. Should the supply be removed from the system for any reason, with the door in the closed position the coil o will be re-energized over the switches p. q, j and the indicating lamp s immediately on resumption of the supply thus maintaining the door closed. Modifications are described wherein themotor has only one field winding and the switches e, g are provided with change-over contacts, and in which the two way switches i. j, may be single way switches. Specification 687,169 a referred to.
展开▼
