GB1352601A - Backlash free torque transmitter - Google Patents

Abstract

1352601 Potentiometers BUNKER RAMO CORP 17 Jan 1972 [22 Jan 1971] 2993/71 Heading HIS An electromechanical transducer comprises two shafts, one partially extending into an opening in the other, the shafts being connected by a limited torque coupling mechanism which consists of at least one body mounted in one shaft and spring urged in a radial direction into a cavity in the other shaft, the body being convexly curved on at least part of its surface to allow it to be cammed out of the cavity when a predetermined torque is exceeded. One embodiment of the invention is shown in the Figure. The hollow shaft, 5, rotates in self lubricating bearings, e.g. sintered metal bearings impregnated with a molybdenum compound. Felt rings, 20, set in annular grooves act as dust seals and a dust cap, 21, closes the end of the housing. A leaf spring type contact 23 fixed to the rotor arm, 22, wipes the wire wound arcuate resistor 24 over an angle somewhat greater than 90 degrees. Connection to the wiper is made via a conductor (not shown), embedded in the rotor arm, connected between the wiper and the slip ring, 25. The rotor arm may be arranged to operate a microswitch at the end of its arcuate travel. The bore, 4, tapers slightly at its ends in order to retain the balls, 16, within it. A substantial clearance, at least 10% of the diameter of the shaft, 11, exists between the shafts 11 and 5, to allow for a certain degree of eccentricity and/or misalignment of the shafts. The spring return of the throttle valve, 7, is designed to have a torque that exceeds substantially, the torque limit of the coupling so that even in the event of the transducer jamming in a position corresponding to the throttle being wide open, the throttle would then close under action of its own spring.