Arnold Umformtechnik Gmbh & Co. Kg

Dirk Doellner

Patrick Werner

Gerhard Moeller

A screwdriver drive design for a screwdriver features an engagement end that is complementary to a fastening element drive design for a fastening element to be screwed. The fastening element drive design includes at least two drive surfaces formed on the fastening element for transmission of a torque suitable for rotation with a tool in a first rotation direction and transition surfaces disposed between these drive surfaces. The transition surfaces form a guide surface for the tool when rotating the tool in the first rotation direction and upon engagement of the tool in the other rotation direction causes an axial outward displacement of the tool, wherein the transition surfaces are formed as outside surfaces, and wherein the outside of the fastening element, outside the transition surfaces and the drive surfaces, lies in a cylindrical jacket forming a recess.

Screw drive design

A drive design for a fastening element in-stalled using screws, in particular, a screw or a nut, comprises drive surfaces () disposed at least approximately in radial planes and transition surfaces () disposed between said drive surfaces. In one embodiment of the outside of the surfaces, the surfaces form a saw shape, In this way, when rotation is in one direction in which a tool en-gages with the drive surfaces (), torque-application results, whereas in the opposite rotational direction a force component is produced that acts on the tool without engaging with the screw drive design. A tool is designed to be complementary to the screw drive design. The screw drive design can be an inner shaping as well an outer shaping. The same applies for a nut. This drive design is intended for designing a screw connector in such a way that it can be tightened once, but cannot be loosened any longer.

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Heilbronn, Germany

Dirk Doellner