GB1084992A - Improvements in driving means - Google Patents

Abstract

1,084,992. Motor driving arrangements; control of motors; mechanical switches. JONES TATE & CO. Ltd. March 6, 1964 [March 8, 1963], No. 9269/63. Headings H2A, H2B and H2J. [Also in Division F2] A driving means, e.g. for a valve, includes an electric motor 11 whose rotary shaft 17 is connected to an output shaft 27 by a mechanical transmission having lost motion whereby the motor can deliver a hammer blow through the output shaft, and whose stator is permitted limited rotational movement in response to operational torque to actuate an electric switch 51 and de-energize the motor, such movement being opposed by a biasing means comprising a spring 37 which urges a flat face of a member 13. into engagement with the flattened face 19 of a cam 15 rotatable with the stator. The transmission comprises, in a gearbox 25, gearing 31, 33, a worm shaft 35, and a worm wheel (73), Fig. 3, coupled by a clutch (67) providing the lost motion, to a ring (81) keyed to the output shaft. The stator rotational movement is limited by cam pin 63 projecting into a gear-box slot 65. In the embodiment shown the member 13 is a plunger and the torque at which the switch 51 is operated is adjustable by rotation of a spindle 47 engaging a ball 39 which determines the position of the spring 37, but in another embodiment, Fig. 4 (not shown), the member is a pivoted lever. The motor may also be switched off by two further switches, one, 121, in response to removal of a cover 119 of a handle 117 by which the output shaft may be manually driven, and the other, 139, in response to actuation by a cam 145 following a predetermined rotation of the output shaft 27.