GB807160A - Improvements in change-speed devices - Google Patents

Abstract

807,160. Variable-speed gearing. SOC. D'ETUDES DE RECHERCHES ET D'APPLICATION MECANIQUES. June 1, 1955 [June 1, 1954], No. 15722/55. Class 80 (2). A V-belt pulley or friction roller whose diameter is varied automatically by load comprises two conical members with studs engaged in opposite-handed helical grooves on the shaft, each conical member being urged axially by a spring. In the belt drive shown in Fig. 1, the driving and driven pulleys comprise pairs of conical members 2 and 12 with studs 3 and 13 engaging opposite-handed helical grooves 4 and 14 on the driving and driven shafts 1 and 11, with pairs of springs 5 and 15, the springs 5 tending to move the members 2 towards each other and the grooves 4 tending to move the members 2 apart, while the springs 15 and grooves 14 act in the opposite senses. In the case of a multiple belt pulley, intermediate double-conical members have studs engaging a longitudinal groove in the shaft. Fig. 7 shows a friction roller for driving a cycle wheel tyre 43 comprising plates 29, 30 mounted on the driving shaft 31 by studs 32, 33 engaging opposite-handed helical slots 34, 35 on the shaft, the plates being urged towards each other by springs 36, 37 and having interpenetrating curved ribs 401, 41 forming the variablediameter friction surface. In the form of friction roller shown in Fig. 10, sleeves 44, 45 secured to the shaft 46 have opposite-handed helical slots 51, 52 engaged by studs 53, 54 on rings 55, 56 with interpenetrating conicalended ribs 57, 58. Internal springs 66 guided on pins 68 urge the rings 55, 56 apart against flanges on the sleeves 44, 45. In other forms, the ribs are replaced by shaped troughs secured on the rings and filled with friction material. Specification 30003/12, [Class 80 (ii)], is referred to.