GB612866A - Improvements in or relating to percussive tools - Google Patents

Abstract

612,866. Percussive tools. STEVENS, A. H. (Wodack Electric Tool Corporation). June 3, 1946, No. 16778. [Class 124] In a percussive tool in which an impact member is retracted and released by power-actuated means and then advanced by a spring, a force-transmitting member is movable with the impact member during the latter portion of the travel thereof and engages the spring to render it operative to cushion the impact member during idle strokes. In the form shown, the tool is in the form of an attachment for use with an ordinary portable electric drill 12, the spindle of which drives a cylindrical cam 21 through the intermediary of a cup-shaped head 30. The cam coacts with a follower 26 on the impact member 13 which is prevented from rotating by a splined connection 15 with a plug 14 forming a tool-bit socket 11, the impact member being surrounded by a power spring 16. The force-transmitting member may take the form of a flanged sleeve 35 surmounted by a loose collar 37 which are so dimensioned that the follower 26 rests on the collar and the arms of the follower are held out of engagement with the surfaces of the cam when the impact member is in its normal position of rest. During idle blows the impact member is carried by inertia beyond its normal rest position, and the impact falls on the collar 37, instead of on the cam and follower arms, and is transferred through the sleeve 35 to the spring 16 after the latter has expended its power to advance the 'impact member. In another form, the collar 37 is integral with the sleeve 35, and the flange of the latter is replaced by a loose washer.