GB743999A - Improvements relating to coupling devices for rotating apparatus - Google Patents

Abstract

743,999. Positive clutches. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Jan. 29, 1954 [Jan. 29, 1953], No. 2630/53. Class 80(2) A clutch is arranged so that when it is disengaged relative rotation between its driving and driven members 26, 24 produces an oscillatory axial movement of the driving member, and is controlled by a holding device including a metallic member (e.g., a disc 17) and a semi-conductor (e.g., 1) having polished surfaces which are moved into and out of engagement on axial movement of the driving clutch member, the metallic member and semi-conductor being retained in engagement to keep the clutch engaged on applying a suitable potential difference between them. The driving clutch member 26 rotates with a driving shaft 3 and pulley 37, and is urged to the left of Fig. 1, towards the driven clutch member, by a spring 27 compressed to a degree determined by an adjustable screw 35. The driven clutch member rotates with a shaft 25 and pulley 36. The driving clutch member 26 is provided with recesses and projections 32, 33, Fig. 3, connected by ramps 34 and engaged by pegs 31 in the driven clutch member. The compression of the spring 27 is insufficient to hold the driving and driven members together and allow torque to be transmitted through the clutch, so that when the driving shaft 3 is rotated, the driving clutch member 26 oscillates axially as the projections 33 &c. ride over the pegs 31. The clutch is engaged by applying a potential to the semi-conductor land metal disc 17 to reinforce the effect of the spring 27. The holding device, comprising the metal disc &c. rotates with the driving shaft 3. The semi-conductor 1 is bonded to a layer of soft rubber 4 in turn bonded to a metal plate 5 carried by an insulating plate 6 on the shaft 3. The metal plate 5 is engaged by a brush 12 through which the potential is applied, while the metal disc 17 is connected to earth. A second, similar, semi-conductor 2 is mounted in the holding device; a potential is applied to it to hold the metal disc 17 to the right against the force of the spring 27 and completely disengage the clutch. The disc 17 may alternatively be a semi-conductor, or the members 1 &c may be of metal to co-operate with a semi-conducting disc 17.