GB782828A - Improvements relating to transmission devices - Google Patents

Abstract

782,828. Variable-speed gearing. MIDLAND SAW & TOOL CO., Ltd. May 3,1955 [May 3, 1954], No. 12824/54. Class 80 (2). In variable-speed V-belt gearing between parallel driving and driven pulleys 12, 13 comprising a variable double pulley assembly 17 on a movable countershaft 21, the latter is mounted in a forked carriage 28 pivoted about a pin 24 and means are provided for causing the shaft 21 to move axially in the carriage as the latter is swung, so as to preserve belt alignment. The assembly 17 comprises connected end flanges 18, 19 and connected inner flanges 30, 31, either the end flanges (as shown) or the inner flanges being axially positioned on the shaft 21 while the other flanges are axially movable. The carriage 28 is pivotally moved by screw-and-nut gearing 42, 51 operated by a hand wheel 43, and the axial movement of the shaft 21 is produced by rollers 56, 57 adjustably carried on the end of the shaft and co-operating with a fixed oblique guide member 53, or by other cam or screw means. Pulley 12 is driven by a motor 10 the frame of which is also pivoted about the pin 24, so that the weight of the frame augmented by a spring if required, tensions the belts. Alternatively, the motor may be slidable, or a spring-loaded jockey pulley may be used. As shown, the pulley 13 drives the lower pulley 11 of a bandsaw through a gear-box 14.