GB2136726A - Tool handle of plastics material - Google Patents

Abstract

The handle, e.g. for screwdrivers, comprises two cone frustums (2,4) of pentagonal cross-section having rounded edges and merging into each other at their bases. The smaller cone frustum facing away from the blade has a rounded tip (3) and the larger cone frustum facing towards the blade merges into a collar (5) at its tip via an encircling concavity (6). The concavity between the cone frustum (4) facing towards the blade and the collar (5) is not contoured in the peripheral direction. <IMAGE>

Description

SPECIFICATION Tool handle of plastics material This invention relates to a tool handle of plastics material, in particular for screwdrivers, comprising two cone frustrums of polygonal cross-section having rounded edges and merging into each other at their bases, in which the smaller cone frustrum facing away from the blade has a rounded tip and the larger cone frustum facing towards the blade merges into a collar at its tip via an encircling concavity.

Tool handles are required to fit comfortably into a human hand, so that a high turning moment may be transmitted whilst extensively safeguarding the skin of the human hand. They should moreover be able to be guided satisfactorily whilst being gripped in a human hand.

These requirements are only fulfilled in a partial manner in the case of a known tool handle according to DE-GM 7 726661. In the case of this known screwdriver, the octagonal contour extends practically throughout the length of the tool handle.

Although in the case of this tool handle it is advantageous for torque transmission that the tool handle is contoured in the region of the largest diameter, that is to say in the area of transition of the cone frustrums, this advantage does not come into full play because of the extensive subdivision of the surface into eight gripping areas with interposed rounded edges, provided to secure easier grasping.

In the case of another known tool handle for screwdrivers according to DE-GM 7915457 a larger truncated sphere and a smaller cone frustrum having six gripping areas on their surfaces in each case, are provided. The base of the larger truncated sphere facing away from the blade is followed by an annular concavity bordering the base of the smaller cone frustrum. The gripping areas of the smaller cone frustrum extend up to the collar at the side of the blade. This tool handle fits well into the hand and may also be guided satisfactorily whilst being gripped by virtue of the annular concavity situated in the middle portion, but the omission of gripping areas in the region of the larger diameter needed in view of the annular concavity is not favourable to the transmission of a high turning moment.

The invention has as its fundamental object to provide a tool handle whereby it is possible to transmit high turning moments whilst extensively safeguarding the hand, and which may be guided by hand in a particularly satisfactory manner whilst being gripped.

In accordance with the invention, this problem is resolved in the case of a tool handle of the kind defined in the foregoing, in that the two cone frustums have a pentagonal cross-sectional base outline and that the concavity between the cone frustum facing towards the blade and the collar is not contoured in the peripheral direction.

In view of the coarser delineation of the two cone frustums even in the larger diametric section, an improved grip is the result. This improved grip is not obtained at the expense of satisfactory guiding during grasping, because the concavity which has the smallest diameter and is consequently less appropriate for transmission of turning moments, is not contoured, so that the index finger and thumb acting within this portion may guide without being obstructed by edges.

The gripping quality of the tool handle may be further improved by the fact that the five gripping areas extending in the longitudinal direction of the handle and situated between rounded edges are formed as shallow troughs having a base concave in the peripheral direction. The gripping quality of the tool handle by appropriate shaping may finally also be improved by the fact that the surface lines of the two cone frustrums extend in a concave fashion.

Moreover, it is advantageous if the surface of the tool handle is slip-resistant. Different possibilities offer themselves to establish a slip-resistant surface.

The surface may consequently be contoured or roughened. In the case of a tool handle of plastics material, it is also possible for the plastics mterial to have added to it a filler of wood chips, wood i granulate, wood flour or mixtures of these materials, which equally endows the tool handle with a slipresistant surface.

The invention wiil now be further described, by way of example, with reference to the accompanying drawings illustrating one embodiment of the invention and in which: Figure 1 shows a sideview of a tool handle for screwdrivers, Figure la shows the tool handle according to Figure 1 in cross-section along the line I - I of Figure 1, and Figure 2 shows the tool handle according to Figure 1 in sideview but with a hand surrounding the same.

The tool handle is produced from plastics material by the injection moulding method, in particular with a mixture of a filler such as wood granulate. A screwdriver blade 1 is integrally cast in the tool handle. The tool handle comprises a cone frustum 2 facing away from the blade and comprising a rounded tip 3, a cone frustum 4 facing towards the blade and a collar 5 is formed as a concavity 6 not contoured in the peripheral direction.

The cone frustum 4 extending at the side towards the blade has a surface line 8 extending with a slight concavity, whereas the cone frustum 2 facing away from the blade has a straight generatrix 7. The generatrix 7 may however also be slightly concave or extend convexly. In cross-section, the cone frustums have the fundamental shape of a pentagon, of which the corners 9 are rounded-off. The areas 10 situated between the corners, which also extend over the region of the largest diameter and act as gripping areas, are formed as shallow troughs having a base which is concave in the peripheral direction, as is clearly apparent from Figure 1 a. The section of maximum diameter, being the area of transition between the two bases of the cone frustums 2,4, is situated at say two-thirds of the total length of the tool handle, reckoned from the side of the blade.

Claims (8)

1. Atool handle of plastics material, in particular for screwdrivers, comprising two cone frustums of polygonal cross-section having rounded edges and merging into each other at their bases, in which the smaller cone frustum facing away from the blade has a rounded tip and the larger cone frustum facing towards the blade merges into a collar at its tip via an encircling concavity, and in which the two cone frustums have a fundamentally pentagonal crosssectional outline and the concavity between the cone frustum facing towards the blade and the collar is not contoured in the peripheral direction.

2. A tool handle according to claim 1, in which five areas extending in the longitudinal direction of the handle and situated between rounded edges are formed as shallow troughs having a base concave in the peripheral direction.

3. A tool handle according to claim 1 or 2, in which the surface lines of the two cone frustums extend in a concave fashion.

4. A tool handle according to any one of claims 1 to 3, having a relatively non-slip surface.

5. A tool handle according to claim 4, in which the surface is profiled or roughened.

6. A tool handle according to claim 4, in which the handle consists of plastics material with a filler of wood chips, wood granulate, wood flour or mixtures ofthese materials.

7. Atool handle of plastics material substantially as hereinbefore described with reference to the accompanying drawing.

8. Atool including a tool handle as claimed in any preceding claim.