GB167677A - Improvements in drilling machines - Google Patents

Abstract

167,677. Smith & Coventry, Ltd., and Wright, I. H. July 29, 1920. Drilling-machines.-In a power-operated drilling- machine, the power feed spindle a<2> is operated through a coiled spring clutch b which frictionally engages a driving-member a during the working stroke, but is automatically released when the pressure on the drill ceases, or when the operating- handle o is turned backwards, or by the operation of an adjustable stop v. The spring b is expanded to grip the internal cylindrical portion of the driving-member o loose on the spindle a<2>, by the pressure of the adjustable stop e carried by a lever d pivoted on the member f fast on the spindle a<2>. The other end of the spring b abuts on the hardened part h attached to the member f, which can be turned in the ordinary manner to work the drill by pulling the handle o which fits loosely in a ring p coupled to the member f through a coiled spring r and stops to bold the handle o frictionally in any set position. For automatic action the lever d has a slot j engaged by a pin k on the crank m mounted loosely on the handle o which has a keyway loosely engaging the key n, so that by turning the handle o about its axis the lever d is operated to put the feed into action. When the pressure on the drill ceases, owing to the work being pierced, the spring b contracts, the play between the key n and the slot allowing this. The feed may also be stopped by raising the handle against the projection u on the lever d, or by an adjustable stop v engaging a projection w on the ring p.