GB2052347A - Tool handle - Google Patents

Abstract

A tool handle particularly a screwdriver handle has first and second frusto-conical portions 2 and 4 with a surrounding groove 5 lying between the bases 6 and 7 of the respective portions 2 and 4. The portion 2 is larger than the portion 4 and has a spherically rounded tip 3. The portion 4 changes into a hexagonally shaped rim 9 via a surrounding groove 8. Gripping portions 10 and 11 are provided on the surfaces of the frusto-conical portions 2 and 4. To provide for maximum turning moment consistent with careful protection of the skin of the hand, as well as for optimum control of the handle during gripping, the gripping surfaces 10 and 11 extend up to and into the sides of the grooves 5 between the portions 2 and 4 but do not extend into the bottom of the groove. <IMAGE>

Description

SPECIFICATION Tool handle The invention relates to a tool handle, particularly for a screwdriver, comprising a first, blade-remote, frusto-conical portion with a spherically rounded tip and a second, blade adjacent, smaller frusto-conical portion whose tip changes into a rim, particularly a hexagonally shaped rim, via a surrounding groove, and whose base changes into the base of the first frusto-conical portion via a further surrounding groove, whereby both frusto-conical portions have gripping surfaces which are equally distributed in the circumferential direction and which extend in the longitudinal direction of the handle.

A design of tool handle, particularlyforascrew- driver which provides a satisfactory grip has been desired for a long time. Having regard to the form and capacity of the human hand, it is an aim to provide the largest possible turning moment whilst ensuring that the skin of the hand is treated gently (see "Griffgerechte Gestaltung eines Schraubendrehergriffes" by Dr. H. Maul and J. Solf in Sonderdruck aus den Refa-Nachrichten, issue No. 5/68, Herausgegeben vom Verband fur Arbeitsstudien Refa E.V., Darmstadt, DE-GM 7726665).

In tool handles in which the turning moment is optimised as in known tool handles of the above specified type, little if any attention is given to the control of the tool handle during gripping by the hand.

The invention has for its object to provide a tool handle which, as well as enabling an optimum turning moment whilst ensuring that the skin is carefully treated, also guarantees a good control whilst gripping.

This object is attained according to the present invention by a tool handle of the above specified type characterised in that the gripping surfaces on the surface of the first frusto-conical portion extend into said further groove.

The tool handle of the present invention is optimally designed with regard to the compromise between turning moment and skin care and also with regard to control during gripping. The gripping surfaces which extend over the base of the larger frusto-conical portion make the handle even more gripable in the region where it has the greatest diameter and consequently the greatest turning moment. Although the gripping surfaces are extended over the base of the large frusto-conical portion and of the small frusto-conical portion, but end before the bottom of the groove, the tool handle slides during gripping, past the curved middle finger which engages in the groove, without the disturbing edges interferring with the grip.

The invention will be further described with reference to the drawing which shows an embodiment of a screwdriver.

The blade 1 of the screwdriver is provided with a cast-on tool handle formed of plastics. The tool handle is composed basically of three associated parts and, more particularly, first, largerfrusto- conical portion 2 with a spherically rounded tip 3, a second, smaller frusto-conical portion 4, and a surrounding groove 5 of part-circular cross-section which lies between the base 6 of the largerfrusto- conical portion 2 and the base 7 of the smaller frusto-conical portion.

The tip of the smaller frusto-conical portion 4 changes into a rim 9 via a groove 8 of part-circular cross-section the rim 9 being of hexagonal construction in order to be able to receive a spanner.

Gripping surfaces 10, 11 which, in this embodiment, are planar, but which may be slightly concave, are arranged on the generating surfaces of the larger frusto-conical portion 2 and also of the small frustoconical portion 4. These gripping surfaces 10, 11 extend over the bases 6, 7 of the frusto-conical portions 2,4 upto and into the region of the sides of the surrounding groove 5. The bottom of the groove 5 alone is free of each profiling. The regions between the gripping surfaces 10, 11 are parts of the generating surfaces of the cones.

The diagrammatic illustration of the handle reproduces the handle in correct scale.

The design of the handle according to the present invention makes possible the application of the largest turning moment with very careful protection of the skin of the hand and also an optimum control of the handle during gripping.

1. A tool handle comprising a first, blade-remote frusto-conical portion with a spherically rounded tip and a second blade-adjacent, smaller frusto-conical portion whose tip changes into a rim via a surrouding groove and whose base changes into the base of the first frusto-conical portion via a further surrounding groove, whereby both frusto-conical portions have gripping surfaces which are equally distributed in the circumferential direction and which extend in the longitudinal direction of the handle, characterized in that the gripping surfaces on the surface of the first frust-conical portion extend up to the groove.

2. A tool handle according to claim 1, characterized in that the gripping surfaces on the smaller frusto-conical portion extend up to the groove.

3. Atool handle substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Tool handle The invention relates to a tool handle, particularly for a screwdriver, comprising a first, blade-remote, frusto-conical portion with a spherically rounded tip and a second, blade adjacent, smaller frusto-conical portion whose tip changes into a rim, particularly a hexagonally shaped rim, via a surrounding groove, and whose base changes into the base of the first frusto-conical portion via a further surrounding groove, whereby both frusto-conical portions have gripping surfaces which are equally distributed in the circumferential direction and which extend in the longitudinal direction of the handle. A design of tool handle, particularlyforascrew- driver which provides a satisfactory grip has been desired for a long time. Having regard to the form and capacity of the human hand, it is an aim to provide the largest possible turning moment whilst ensuring that the skin of the hand is treated gently (see "Griffgerechte Gestaltung eines Schraubendrehergriffes" by Dr. H. Maul and J. Solf in Sonderdruck aus den Refa-Nachrichten, issue No. 5/68, Herausgegeben vom Verband fur Arbeitsstudien Refa E.V., Darmstadt, DE-GM 7726665). In tool handles in which the turning moment is optimised as in known tool handles of the above specified type, little if any attention is given to the control of the tool handle during gripping by the hand. The invention has for its object to provide a tool handle which, as well as enabling an optimum turning moment whilst ensuring that the skin is carefully treated, also guarantees a good control whilst gripping. This object is attained according to the present invention by a tool handle of the above specified type characterised in that the gripping surfaces on the surface of the first frusto-conical portion extend into said further groove. The tool handle of the present invention is optimally designed with regard to the compromise between turning moment and skin care and also with regard to control during gripping. The gripping surfaces which extend over the base of the larger frusto-conical portion make the handle even more gripable in the region where it has the greatest diameter and consequently the greatest turning moment. Although the gripping surfaces are extended over the base of the large frusto-conical portion and of the small frusto-conical portion, but end before the bottom of the groove, the tool handle slides during gripping, past the curved middle finger which engages in the groove, without the disturbing edges interferring with the grip. The invention will be further described with reference to the drawing which shows an embodiment of a screwdriver. The blade 1 of the screwdriver is provided with a cast-on tool handle formed of plastics. The tool handle is composed basically of three associated parts and, more particularly, first, largerfrusto- conical portion 2 with a spherically rounded tip 3, a second, smaller frusto-conical portion 4, and a surrounding groove 5 of part-circular cross-section which lies between the base 6 of the largerfrusto- conical portion 2 and the base 7 of the smaller frusto-conical portion. The tip of the smaller frusto-conical portion 4 changes into a rim 9 via a groove 8 of part-circular cross-section the rim 9 being of hexagonal construction in order to be able to receive a spanner. Gripping surfaces 10, 11 which, in this embodiment, are planar, but which may be slightly concave, are arranged on the generating surfaces of the larger frusto-conical portion 2 and also of the small frustoconical portion 4. These gripping surfaces 10, 11 extend over the bases 6, 7 of the frusto-conical portions 2,4 upto and into the region of the sides of the surrounding groove 5. The bottom of the groove 5 alone is free of each profiling. The regions between the gripping surfaces 10, 11 are parts of the generating surfaces of the cones. The diagrammatic illustration of the handle reproduces the handle in correct scale. The design of the handle according to the present invention makes possible the application of the largest turning moment with very careful protection of the skin of the hand and also an optimum control of the handle during gripping. CLAIMS

1. A tool handle comprising a first, blade-remote frusto-conical portion with a spherically rounded tip and a second blade-adjacent, smaller frusto-conical portion whose tip changes into a rim via a surrouding groove and whose base changes into the base of the first frusto-conical portion via a further surrounding groove, whereby both frusto-conical portions have gripping surfaces which are equally distributed in the circumferential direction and which extend in the longitudinal direction of the handle, characterized in that the gripping surfaces on the surface of the first frust-conical portion extend up to the groove.

2. A tool handle according to claim 1, characterized in that the gripping surfaces on the smaller frusto-conical portion extend up to the groove.

3. Atool handle substantially as hereinbefore described with reference to the accompanying drawing.