GB1391176A - Tapping attachments - Google Patents

Abstract

1391176 Tapping units FRANK GUYLEE & SON Ltd 8 June 1972 [14 June 1971] 27791/71 Heading B3N A tapping unit is provided with means whereby an overload release is brought about at a particular torque, said means including driving and driven elements, 16 and 18 respectively, disengageable means, balls 22, for establishing a driving connection between the two, resilient means 20 which must be overcome to allow disengagement of the elements, and a distance piece, body part 32, for determining the torque at which said resilient means will be overcome, said distance piece being associated with or formed integrally with a holder for a particular size of tapping bit. A driving sleeve 24 is rotatably fast but axially movable with respect to driven element 18 by balls 26 whilst being axially fast but rotatably free with respect to driving element 16 through balls 15. A tap holder 30 is mounted in the driving sleeve by balls 46. A sleeve part 34 biased outwardly is mounted therein by balls 40 which coact with a flared end portion 42 to give a wedging action. The distance d shown in Fig. 2, determines the pre-loading on springs 20 and thus the torque at which elements 16, 18 become disengaged. A sleeve 50 retains balls 15, 26 and 46 and is movable axially to allow balls 46 to disengage body part 32 such that the holder 30 can be replaced by another of a differing size. The tapping unit may have axial float means and/or radial float means associated therewith.