Socket to clampingly hold dental tools

A socket for clamping a cylindrical shaft of a dental tool, said socket having an outer sleeve, a clamping sleeve, and a displaceable ram, said outer sleeve having means for mounting the socket for rotation in a housing, said ram being inserted in said outer sleeve and being freely, axially displaceable between a position adjacent a first end of the outer sleeve and an inwardly disposed position that is closer to a second end of said outer sleeve, said ram having outer tapering surfaces extending at an angle to the axis of said outer sleeve on an end of the ram pointing towards said second end of said outer sleeve, said clamping sleeve having longitudinal slots extending inward from a first end to form resilient tongues, each of said tongues having an inner tapering surface extending at an angle to the axis of the clamping sleeve, said clamping sleeve being inserted into the outer sleeve with the first end of the clamping sleeve adjacent the outer tapering surfaces of said ram, means for securing the clamping sleeve in an axially immobile position in the outer sleeve, said ram being moved from a retracted position towards the clamping sleeve with the tapering surface of the ram coacting with the tapering surfaces of the tongues to urge the tongues from a closed position on a shaft of a tool inserted in the clamping sleeve to a radially outward unclamping position to release said tool, said angle of the outer tapering surfaces being greater than the angle of the inner tapering surfaces so that the contact between tapering surfaces of each tongue and ram form substantially a line contact with one another that is offset from the slots while in the unclamping position.