WO1990001399A1

WO1990001399A1 - Inclinable polygonal wrench

Info

Publication number: WO1990001399A1
Application number: PCT/SE1988/000403
Authority: WO
Inventors: Ingvar Sundberg
Original assignee: Ingvar Sundberg
Priority date: 1987-05-06
Filing date: 1988-08-10
Publication date: 1990-02-22
Also published as: SE8701853L; SE8701853D0; EP0386014A1; JPH03500391A; SE458097B

Abstract

Polygonal wrench with a gripping part bounded by a groove (3), whereby the gripping part can be adapted to the required tightening moment by varying the height of the gripping part and the degree of inclination of upper part (2) depends on the design of groove (3).

Description

Inclinable polygonal wrench

The present invention relates to an inclinable polygonal wrench, the part of which situated lowest has a gripping section for engaging a recessed gripping surface of a screw and has also a groove between the upper and the lower part, which, in conjunction with the height of the lower part, makes it possible to incline the upper part.

There are many differentdesigns of polygonal wrenches intended or inclining the handle part. Inclining the handle part makes it easier to turn screws in positions which are difficult to reach, and prevents turning by 3^0° without changing the grip, since the handle is in line with the gripping section. All the types hithertoavailable are of spherical design with radii having different numbers of degrees. The different numbers of degrees of the radii have resulte'd in different sizes of gripping surface. With spherical shapes of small radius the friction surface is large but the inclination is small. With spherical shapes of large radius a larger inclination can be achieved^ but the frictional surface is smaller. The above disadvantages are so considerable that none of the existing polygonal wrenches meets the current requirements.

Whatever the radius of the spherical shape, all polygonal wrenches with spherical shape are difficult to produce while requiring an unnecessarily large amount of material, but their main disadvantage consists in the fact that the effective gripping surface is reduced owing to the spherical shape. In addition, the spherical shape gives rise to large friction in the parts which do not directly affect the screw-down moment.

The invention described in the introduction has been developed in order to provide simpler, more easily machinable, better functioning and less costly polygonal wrenches. The enclosed drawings and the description below emphasise the advantages of the present invention.

Fig. 1 shows an upper part (2) which may be of appropriate shape and length, which means that the upper part can have a similar as well as a different shape as the bottom part (4) .

Pig. "I also shows a groove (3) in upper part (2) which is next to the lower part (4). Groove (3) can be of different width, depth and shape, depending on the required degree of inclination. The upper flank (7) of the groove is intended to guide the polygonal wrench towards the upper flank of the screw so as to achieve a good grip. The flanks of the groove may be concave, inclined or straight. If required, the edges of the upper or lower flank or both flanks can be chamfered in order to reduce the friction when inclining the upper part.

Fig. 1 shows also part (4) situated lowest, the shape of which is, in this case, hexagonal, but it is possible to impart different shapes to the lower part, and fig. 2 shows certain different shapes, but there is of course no reason why other shapes should not occur. The height of lower part (4) is adapted to the required gripping surface and the degree to which upper part (2) is inclined. The upper flanks (7) of lower part (4) are equivalent to the shape of the groove. Underside (5) of lower part (4) is flat, and in addition the edges (6) can be chamfered, which reduces friction.

What has been described above may be summarised as follows: Polygonal wrenches enabling the production of differently shaped upper parts have a lower part, the height of which is equal to the total gripping surface between the recessed gripping surface of the screw and the gripping surface of the lower part. If the upper part is inclined slightly, the gripping surfaces are concentrated at the deepest part of the screw's recess, thus achieving an optimal grip. If the gripping surface of the lower part is 5 n relation to the gripping surface of the screw's recess, the upper part can, if its length amounts to 95 mm, be inclined by about 40°.

Owing to two mutually independent settings of gripping surface and inclination, this increases the possibilities of achieving a polygonal wrench capable of satisfying most requirements.

Claims

Claim

Inclinable polygonal wrench c h a r a c t e r i s e d in t h a t it comprises an upper part (2) and a lower part (4) constituting a. gripping part for engagement of a recessed gripping surface of a screw as well as a groove (3) between said parts (2, 4), whereby, depending on its height, the lower part has a gripping surface corresponding with the screw's recessed gripping surface of corresponding height, whereby the design of the groove as regards its depth and width as well as the height of the lower part are adapted to the required degree of inclination.