GB191202067A - Improvements in Worm Gearing. - Google Patents

Abstract

2067. Robinson, A. S. F. Jan. 25. Transmission gear of invariable ratio.-In worm speed-reducing gearing applicable to motor-vehicles &c., two worms on intergeared shafts gear with opposite sides of a worm-wheel, the worm shafts being movable endways and connected to one another by pivotally mounted levers in order to divide the thrust and equally distribute the work. In the arrangement shown in Fig. 1, the worm-wheel a is driven simultaneously on opposite sides by worms b of similar thread mounted on shafts geared together by pinions c so as to rotate in opposite directions, the driving-shaft x being coupled to one of the pinions c by pins x'. The worm shafts are movable endways within ball bearings k and carry between collars i loose rings or sleeves h trunnioned in levers d, which are pivotally supported at e in the gear-box and pinned or geared to one another at f, a certain slackness in the joints allowing the required movements. The thrusts of the shafts being in opposite directions, one is balanced against the other by the arrangement of the levers d. Modified means of driving, and interconnecting the worm shafts b are described. The driving- shaft x may be arranged between the two worm shafts, being geared to one shaft by spur pinions and to the other by chain gearing. To reduce the size of the gears, the worm shaft may be connected by universal shafting to two other shafts arranged at a suitable distance apart, or the worm shafts may be inclined to one another in the plane of the worm-wheel and geared together by bevel-pinions. The fixed bearing-supports k may be dispensed with, the worm shafts being supported by a duplicated series of equalizing-levers such as d, arranged at one or both ends of the worm shafts. In another arrangement, worms of oppositely-inclined threads, rotating in the same direction, gear with a double worm-wheel in which the adjacent members have oppositely-inclined teeth. In this modification, the worm shafts may be connected by chain or spur gearing. Instead of oppositely-cut teeth on adjacent members, the right and left hand teeth of the wormwheel may be cut through one another on a single member. In the arrangement shown in Fig. 11 and designed to give maximum space between the road and the gear-box of a motorvehicle, the worm shafts b carry worm-wheels c and are driven by an horizontal worm shaft x.