Actuating tool

Details Actuating tool Actuating tool

2000-07-05

2001-10-16

Hail, III, Joseph J. (Department: 3723)

Tools

Wrench, screwdriver, or driver therefor

Having work engaging and force exerting portion inserted...

C081S013000

Reexamination Certificate

active

06302001

ABSTRACT:

The invention relates to an actuating tool for a fastener having an internal polygon arrangement in accordance with the preamble of claim
1
.
An actuating tool of the initially described type is known from German Patent DE-PS 44 16 268. It serves to screw in or unscrew hexagon socket screws. For this purpose, the tool is provided with a hexagon socket insert bit that fits into the hexagon socket of the screw. In an insertion element that is provided with the hexagon socket insert bit, an elastic clamping device is arranged, which is accommodated in a recess of the insertion element. When the tool is inserted into the hexagon socket, a force is applied to the clamping arrangement designed as a snap ring. The beveled open ends of the snap ring thereby move toward each other so that the outside diameter of the ring is reduced. This allows the insertion element to slide into the hexagon socket of the screw. The disadvantage of this prior-art actuating tool is that the snap ring can very easily slip within the recess, which in many cases makes it impossible to insert the tool into the hexagon socket. A further disadvantage is that the snap ring is compressed in such a way that the bevels of the ends do not project above the edge of the recess so that a secure hold of the tool within the hexagon socket is not ensured in all cases.
German Utility Model 297 08 764 discloses a screwdriver with a polygonal engagement area. It is provided with a recess into which a plastic ring is inserted, which is elastically deformed when the tool is pushed into the internal polygon arrangement of a screw. Another embodiment of the screwdriver provides for a spring washer with a rosette-like contour to be inserted into the recess, whereby the areas between its rounded edges are curved. With frequent use, however, such clamping elements wear quickly, particularly the plastic ring. The spring washer with the rosette-type contour is complex and costly to produce.
Thus, the object of the invention is to create an actuating tool for a fastener with an internal polygon arrangement, which obviates the initially described disadvantages.
This object is attained by means of an actuating tool with the features cited in claim
1
. The tool is distinguished, in particular, in that a recess for a spring washer is made in a tool head with an external polygon arrangement, that the spring washer is in partial areas elastically supported against sidewalls of the recess and in its no-load state projects above at least one, preferably above each face of the external polygon arrangement, and that the depth of the recess is greater than or equal to the dimension of the spring washer measured in the direction of the depth. The elastic support advantageously ensures that the spring washer is centered when the tool head is first inserted into an internal polygon arrangement of a screw and that it retains this position after the tool is withdrawn from the screw. Thus, the spring washer is fixed or braced by the elastic support within the recess. Consequently, the insertion force during subsequent insertion processes remains nearly constant since the limiting edges of the internal polygon arrangement strike substantially the same position of the spring washer when the tool is inserted. As a result, the force is transmitted from the limiting edges to the spring washer at substantially always the same tangent angle. The actuating tool according to the invention is thus distinguished by the fact that the spring washer cannot slip uncontrollably within the recess, which ensures simple and secure insertion of the tool at a nearly constant insertion force. Since the spring washer in its no-load state projects above at least one, preferably above each flat face of the external polygon arrangement, constant forces act on the spring washer from each flat face of the internal polygon arrangement when the tool is inserted. The fact that the depth of the recess is equal to or greater than the dimension of the spring washer measured in the direction of the depth ensures that the spring washer is completely received by the recess when a force is applied.
A preferred embodiment provides that the spring washer forms a turn in the manner of a helical spring. In other words, the spring washer is crossed, with the opposite ends of the preferably open spring washer being laterally offset. Through this crossing of the spring washer, the turn of which thus extends along an imaginary helix, said spring washer is at least in partial areas elastically supported against the sidewalls of the recess. This ensures secure positioning of the spring washer within the recess. In a preferred embodiment, the recess extends in a plane, whereby a normal of said plane coincides with a longitudinal axis of the actuating tool. The spring washer thus extends in a concentric circular path around the longitudinal axis of the tool.
Furthermore, it is preferably provided that the ends of the open spring washer nearly touch each other in their loaded state. A nearly closed spring washer is thus formed, which is elastically supported against the flat faces of the internal polygon arrangement. This achieves a secure hold of the tool within the screw.
Furthermore, it is preferably provided that the recess is formed as a substantially rectangular or U-shaped groove. Consequently, the crossed spring washer can at least in partial areas be supported against the sides of the groove. Thus, it retains its position with respect to the longitudinal axis of the tool.
A particularly preferred embodiment provides that the spring washer is formed by preferably a spring-hard wire, which can have a substantially circular cross section. Alternatively, it may be provided that the spring washer has an angular cross section, which is preferably triangular, rectangular or hexagonal. The cross section may also be trapezoidal. An angular cross section has the particular advantage that a diagonal face of the spring washer meets the limiting edges of the internal polygon arrangement. This causes substantially equal forces to act during insertion, since the limiting edges meet the diagonal to create a radial force component that pushes the spring washer into the recess. This is particularly advantageous if the dimensions of the tool and/or the internal polygon arrangement of the screw have tolerances.
A preferred embodiment provides that the diameter of the cross section of the spring washer be 0.07 to 0.14 times the width across flats defined by the polygon arrangement.
In a particularly preferred embodiment, the actuating tool is distinguished by the fact that the tool head is formed by two spherical segments, that their bases are facing each other and are spaced at a distance from each other, and that their center points—measured in the direction of the longitudinal axis of the actuating tool—are preferably spaced a distance from each other. Thus, a spherical head is formed, which comprises two halves of a sphere, has the dimensions of the external polygon arrangement, and permits insertion of the actuating tool into the internal polygon arrangement even if the longitudinal axis of the actuating tool is not aligned with the longitudinal axis of the screw. This is particularly advantageous if the screw is located behind an obstacle. Furthermore, it is provided that the center point of the first spherical segment and the center point of the second spherical segment are located along the longitudinal axis of the actuating tool and that the center points are located within a space between the bases of the spherical segments.
A particularly preferred embodiment provides that one spherical segment of the spherical head is arranged on a shank of the actuating tool, and that on the other spherical segment a truncated cone is preferably attached whose lateral surface forms an angle &agr; with the normal, i.e. the longitudinal axis of the actuating tool. Furthermore, it is preferably provided that the center axis of the truncated cone coincides with the longitudinal axis of the actuating tool. The trunca

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