GB191005872A - Improvements in Belt Driving-mechanism. - Google Patents

Abstract

5872. Vernon, P. V. March 9. Driving machines.-Relates to variable-speed belt transmission-gearing applicable to verticalspindle drilling-machines, and of the type comprising driving and driven pulleys, only one of which is stepped, connected by a belt which also passes round delivery and return idlers, and consists in providing one of the idlers with steps corresponding in number with the said transmission stepped pulley, in order to aline the belt and to reduce, and in some cases dispense with, belt adjustment for tension in changing the speed. As shown in Fig. 1 the drum C on a shaft D drives the stepped transmission pulley A on a drill &c. spindle B at right-angles thereto, by means of a belt E passing round delivery and return idlers, the delivery idler having a number of steps G, H corresponding to the stepped pulley A and arranged to deliver the belt correctly thereto. The return idler F and the driving-drum C may be axially slidable, or are of sufficient breadth to allow the belt to shift laterally in driving different steps. The step of the idler may be adjustable either separately or together to prevent the edges of the belt from fouling, or to bring the belt into proper alinement. As shown in Fig. 1 the stepped idler may be mounted in a forked arm J, which may be rotated through a semicircle in a socket K, being secured in position by a pin M. It may be adjusted horizontally to regulate the tension. The steps of the idler may be slidable either separately or together. In the latter case as shown in Fig. 6, the spindle P- upon which the idler is rotatably mounted is axially adjustable in a bracket N, being secured by a clamping- screw R. The bracket N is adjustably secured by a clamping-screw O to the arm L. An arm S prevents displacement of the belt, and guides T prevent it from being placed upon a step that is not in correct alinement. The proportions of the pulleys may render unnecessary any adjustment of the idler.