GB252805A - A new or improved change speed gear - Google Patents

Abstract

252,805. Armstrong, A. R. March 7, 1925. Variable-speed gearing of the sliding-gear type is modified to facilitate the engagement of the gears and to secure a resilient transmission. The speed is changed by sliding a screw spring device carrying a plurality of gears h, i adapted to mesh with gears such as e fast on a countershaft a constantly driven from a shaft b. The device comprises outer and inner sleeves g, n screwing together and separated by a spring p. The sleeve g carries the gears h, i and may carry a dog clutch member j for direct driving from a like member s on the shaft b. The sleeve n is splined on the driven shaft f. When the combined device is slid to engage, say, the pair h, e, the sleeve g is held against axial movement by the striking-means, and the sleeve n screws along until stopped by the thrust in the spring. Gradual pick up of the drive and resilient transmission result. The action is the same when the clutch teeth pick up. The unscrewing action when the device is disengaged may be facilitated by restrained revoluble gears r at positions intermediate of the gear positions. Alternatively, the combined device may be adapted to slide on the countershaft.