Bit assembly

Claim 1

A bit assembly comprising: a. a hollow bit holder having top and bottom walls, side walls and end walls, one of said end walls having an aperture therein communicating with the hollow interior of said holder, said bottom wall having an opening therein communicating with the hollow interior of said holder; b. said one end wall having a shoulder formed thereon along the lower periphery of the end wall aperture; c. an interior support member formed on the bit holder walls on the opposite side of the hollow interior of said holder from said shoulder; d. a tool bit having a root portion inserted through the bottom wall opening into the hollow interior of said bit holder, said root portion having retaining means thereon for interacting with said bit holder support member, said root portion having an internally threaded bore which is axially aligned with the end wall aperture, said bore having its opening countersunk; and e. a screw inserted through the end wall aperture and screwed into the bore of said root portion, said screw having a head bearing against and being supported by said one end wall shoulder, said screw having a frusto-conical surface formed between its head and threaded shank bearing against said countersunk bore opening; f. said one end wall shoulder, said screw head, said countersunk bore opening, and said frusto-conical screw surface all being arranged relative to each other whereby forces transmitted to said screw head intersect at a point on the axis of said screw.