GB636021A - Improvements in or relating to tool holders or chucks for twist drills - Google Patents

Abstract

636,021. Chucks and sockets. NORLANDER, H. G. Feb. 18, 1948, No. 4805. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 2, 1949]. [Class 83 (iii)] In a chuck for twist drills, a driving member 9, Fig. 2, adapted to engage the drill flutes so as to permit combined rotary and axial movement, but to prevent purely rotary movement, of the drill relatively thereto is connected to an axially-movable inner sleeve 2 which is secured to an axially-movable outer sleeve 3, and clamping balls 12 for preventing axial movement of the drill relatively to the member 9 are arranged in recesses in the sleeve 2 so as to co-act with a ring-shaped wedge-member 14 and engage the portions of the drill between the flutes thereof. The balls are moved radially outwards by moving the sleeve 3 axially against the action of a spring 8. In a modification, Fig. 5 (not shown), the balls are replaced by rollers. In another modification, Fig. 6, the driving member is formed integrally with the inner sleeve and a rotatable outer sleeve 3 is screwed to an axially slidable member 17 which is locked to the inner sleeve by means of a ball 18. In a further modification, Figs. 8 and 9 (not shown), the chuck body is provided with a recess to receive the locking ball when the inner sleeve is moved axially. In a still further modification, the inner sleeve is screwed directly to the chuck body.