Patent ID: 8784018
Filing Date: 2014-07-22
Classification: B23B,Y10T

Abstract:
1. Drilling tool for chip removing machining, comprising: a basic body having front and rear ends, between which a first center axis extends around which the basic body is rotatable in a given direction of rotation, and a loose top having front and rear ends, between which a second center axis extends, the front end of the loose top including one or more cutting edges, wherein the front end of the basic body comprises a jaw between two axially protruding, peripherally situated branches that are elastically bendable, the branches are capable of resiliently clamping the loose top in the jaw by inner support surfaces of the branches being resiliently pressed against external side contact surfaces of the loose top, and capable of transferring torque to the loose top via tangential support surfaces of the branches and cooperating tangential contact surfaces of the loose top, wherein the inner support surface of each of the individual branches extends between first and second tangentially separated side borderlines, the first tangentially separated side borderline is heading and the second tangentially separated side borderline is trailing during rotation of the tool, wherein each external side contact surface of the loose top extends between first and second side borderlines, the second side borderline rotationally trailing the first side borderline and is included in an edge to a trailing part surface, besides which the loose top is axially insertable into the jaw and turnable into and out of an operative engagement with the branches, wherein a second imaginary diametrical line, which extends perpendicular to the second center axis of the loose top between abutting edges that abut the second side borderline of each of the external side contact surfaces, has a length that is greater than the length of an analogous first diametrical line, which extends a shortest possible distance between the inner support surfaces when the branches are unloaded, and has opposite end points located at tangential distances from the first tangentially separated side borderline and the second tangentially separated side borderline of the respective inner support surface in such a way that upon a turning-in operation of the loose top into engagement with the branches a successively increasing deflection of the branches is provided by the edges up to a predetermined intermediate position of maximum clamping force, so as to then decrease during the continued turning of the loose top until an end position is reached, and during the final phase of the rotary motion between the intermediate position and the end position, the clamping force in the branches assists in bringing the loose top to the end position.