SCREWING DEVICE Russian patent published in 2005 - IPC

FIELD: devices for fastening or securing constructional elements or machine parts together, particularly specially-shaped heads of bolts or screws for rotations by a tool.

SUBSTANCE: screwing device has screw and tool for screw driving. Screw is provided with head having upper surface and groove with the first depression aligned with upper surface and with zone having axial section with substantially straight walls. Tool has engaging part complementary to the first depression. Groove is provided with the second depression formed in bottom of the first depression and having diameter lesser than that of the first depression. Tool is provided with central part shaped so that central part is complementary to the second depression. The first depression has section transversal to screw axis, which is shaped as six-pointed star formed in accordance with Torx® standard (i.e. ISO 10664). The second depression and the central tool part are of round shape. Screw has transition surface extending at the first angle from the first depression to the second one. Tool has mating surface extending at the second angle from engaging part to central part, wherein the first angle is greater than the second one so that a space is created between transition surface and mating surface when tool is inserted in the groove. The space widens towards central tool part.

EFFECT: improved engagement between screw groove and tool, as well as simplified tool structure and elimination of tool production cost increase.

3 cl, 3 dwg