Patent ID: 8505893

Claim:
A system comprising: a tool with a rotational axis about which the tool rotates during operation and a tool shaft with a cylindrical surface; a tool holder with a clamping chuck for receiving and clamping the tool shaft, wherein the clamping chuck operates to clamp a tool in a torque proof manner; a pullout preventer for locking the tool against an axial migration in the direction of the rotational axis of the tool and out of the tool holder, wherein the pullout preventer comprises: at least one locking element with a first form locking surface that has at least a partially circular shape; and at least one locking groove which corresponds thereto and receives the at least one locking element, the at least one locking groove has a second form locking surface that has at least a partially circular shape that extends between substantially parallel and separated edges of the at least one locking groove and along a substantial portion of the length of the at least one locking groove; wherein the at least one locking element and the at least one locking groove interact in a form locking manner such that there is contact between substantial portions of the first and second form locking surfaces and an axial lock is formed by the interaction between the first form locking surface of the at least one locking element and the second form locking surface of the at least one locking groove when the at least one locking element is located in the at least one locking groove, wherein one of the at least one locking element and the at least one locking groove is disposed in the cylindrical surface of the tool shaft and the other one of the at least one locking element and the at least one locking groove is disposed in the tool holder, wherein the at least one locking groove follows a path that has a first terminal end, a second terminal end that is separated from the first terminal end, and a curved portion angularly disposed relative to the rotational axis of the tool and having an acute angle relative to the rotational axis of the tool when the tool is operatively associated with the tool holder, the curved portion further defined by a cylindrical surface and at least two separated points on the curved portion being substantially radially equidistant from two separated points on the rotational axis when the tool is operatively associated with the tool holder, wherein the locking groove does not completely encircle the cylindrical shaft.