DE29816210U1 - Screwdriver bit for hexagon socket screws - Google Patents

Description

PRINCE &

PATENT ATTORNEYS Manzingerweg 7

EUROPEAN PATENT ATTORNEYS D-81241 Munich

EUROPEANTRADEMARKATTORNEYS Tel. +49 89 89 69 80

9 September 1998

Berner GmbH
Bernerstrasse 6
74653 Künzelsau

Our reference: B 3590 DE
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Screwdriver insert for hexagon socket screws

The invention relates to a screwdriver insert for hexagon socket screws, with a cylindrical drive part for insertion into a hexagon socket recess in a screw head.

Such a screwdriver bit, also known as a "bit", results in an essentially positive transfer of drive forces to a screw. However, in the case of hexagon socket designs, which are also known on the market under the brand name "Torx", this only applies when both the screwdriver bit and the recess in the screw head are in new condition. In new condition, there must be a certain amount of play between the outer surface of the screwdriver bit and the inner surface of the recess in the screw head, both of which have force application surfaces that are parallel to one another, so that the screwdriver bit can be inserted into the recess on the screw head and does not jam there.

If the screwdriver bit and/or the recess in the screw head wear out, the cylindrical drive part of the screwdriver bit is no longer guided sufficiently in the recess in the screw head, so that angular deviations can occur between the central longitudinal axis of the screwdriver bit and the central longitudinal axis of the screw to be screwed in; the screwdriver bit can therefore be inserted crookedly into the recess in the screw head.

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In order to eliminate the risk of such angular deviations with increasing wear, screw-driving inserts are also known on the market in which the drive part is not cylindrical but conical. This means that the screw-driving insert jams on the outer edge of the recess in the screw head when inserted. This also means that in new condition, in which the tolerances between the drive part and the recess in the screw head are very small, the drive part can only be inserted into the recess slightly. Complete insertion is only possible after a certain amount of wear. Overall, it can be observed that the screw-driving insert easily slips out of the recess in the screw head or jams there. In addition, point or line contact between the conical drive part and the outer edge of the recess in the screw head results in very high surface pressure, which damages the contour of the recess in the screw head and the drive part.

The invention therefore has the object of providing a screwdriver insert

which, regardless of wear-related tolerances, enables reliable guidance of the screwdriver bit in the recess in the screw head without the screwdriver bit becoming jammed in the recess.

For this purpose, a screwdriver bit of the type mentioned at the beginning is provided with a conical extension that follows the outer contour of the drive part and the length of the cylindrical drive part is selected so that the conical extension can come into contact with the outer edge of the recess in the screw head. The cylindrical part therefore penetrates completely into the recess in the screw head and guides the screwdriver bit relative to the screw. When the drive part of the screwdriver bit is completely inserted into the recess, the conical extension comes into contact with the outer edge of the recess, so that it is not possible to insert the screwdriver bit into the recess in the screw head at an angle. This means that no angular deviations can occur and the screw to be screwed in can no longer wobble when screwing in. The reliable guidance of the

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The screwdriver insert in the screw head makes it possible to process drilling and chipboard screws, for example, with one hand, as the screws center themselves and no longer have to be held with the other hand.
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Advantageous embodiments of the invention emerge from the subclaims.

The invention is described below with reference to a preferred embodiment shown in the accompanying drawings, in which:

- Figure 1 is a side view of a screw-turning insert according to the invention; and

- Figure 2 is a sectional view along plane II of Figure 1.

The screw driver insert 10 has a hexagon section 11, which can be accommodated in a drill, for example, and a cylindrical drive part 12, the contour of which is adapted to a hexalobular recess of a screw head (not shown in the drawings). The drive part 12 is followed by an extension 14, the outer contour of which continues the outer contour of the drive part. The extension 14 is conical with a cone angle of 3.6°.

When inserting the screwdriver bit 10 into a hexagon socket recess in a screw head, the cylindrical drive part 12 penetrates completely into the recess with its entire length L. The length L of the cylindrical drive part 12 is dimensioned such that the insertion of the screwdriver bit into the recess of the screw head is completed by the conical extension 14 resting on the outer edge of the recess in the screw head. The length L changes depending on the outer diameter A or the inner diameter B of the hexagon socket design and can easily be determined by a person skilled in the art based on the known dimensions of the recesses depending on the various diameters.

Claims (3)

PRINZ &PARTNER™" "' " PATENT ATTORNEYS Manzingerweg 7 EUROPEAN PATENT ATTORNEYS D-81241 Munich EUROPEANTRADEMARKATTORNEYS Tel. +49 89 89 69 80 9 September 1998 Berner GmbH
Bernerstrasse 6 74653 Künzelsau Our sign; B 3590 DE
St/bra
10 Protection claims 1. Screwdriver insert (10) for hexagon socket screws, with a cylindrical drive part (12) for insertion into a hexagon socket recess in a screw head, characterized in that the cylindrical drive part (12) is followed by a conical extension (14) which continues the outer contour of the drive part (12), the length (L) of the cylindrical drive part (12) being selected such that the conical extension (14) can come into contact with the outer edge of the recess in the screw head. 2. Screwdriver insert according to claim 1, characterized in that the conical extension (14) is conical. 3. Screwdriver insert according to claim 2, characterized in that the conical extension (14) has a cone angle of 3.6°.