Machine tool holder having opposed ramp members

Claim 1

A machine tool holder comprising: a body, mounting means adapted to mount the tool holder on a material working machine, a conic bore in the body having a longitudinally extending axis, a shank on a tool mounting means received in said conic bore, said shank having a conic surface that matingly fits within the conic bore and two ramp surfaces which are disposed on opposite sides of the shank with respect to said axis, and clamping means comprising two bodies each having a ramp surface, said bodies being located in bores which are radial to said axis of said conic bore, said bodies and bores being of complementary non-circular cross-section so that said bodies are non-rotatable but slidably secured in said bores, a screw member acting simultaneously and equally on said bodies to urge them radially inward, and wherein the ramp surfaces of said shank are complementarily shaped and oriented with respect to said ramp surfaces of said bodies whereby to engage over a substantial area as the bodies are urged radially inward by said screw member to draw the shank into said conic bore and clampingly locate and centre the shank in said conic bore.