Trepanning tool

Abstract

A tool for removing a disk or cylindrical core from a workpiece which includes a shank, an extension piece and cutting elements, the extension piece being in the form of a hollow cylinder and including apertures in the wall thereof for the introduction therein of a coolant. An axially movable centering element is positioned with the extension piece, the centering element including a centering spigot which fits into a cup-shaped centering piston, plate springs within the piston and against which the centering spigot is movable, and an elastic ring therearound for contact against the inner wall of the hollow cylinder. Upon positioning of the tool onto a workpiece and consequently the centering spigot at the center of the core to be cut, and upon application of axial movement of the tool towards the workpiece, the centering spigot is axially movable within the piston in a fashion to provide a constantly increasing resistive force up to a point wherein the elastic ring releases its resistive contact against the inner wall of the hollow cylinder and the piston itself axially moves within the hollow cylinder. The resistive force of the centering spigot then becomes constant, based on the force exerted on the piston resulting from the introduction of coolant into the hollow cylinder. Multiple extension pieces of varying lengths can be utilized, or none can be used, provided the shank is of the form of a hollow cylinder.

Dependencies are inferred from the claim text.