HAND HOLDABLE TOOL

Abstract: A hand holdable tool, such as a writing implement, knife or brush, comprises a functional end such as a writing tip (17) and a handle or shaft, the shaft comprising a first portion (19) and a second portion (21) which extends between the first portion and the functional end, the first portion being substantially cylindrical or tapering away from the second portion, and the second portion being substantially frusto-pyramidal and tapering from the first portion to the functional end, a central axis of the first portion being inclined to a central axis of the second portion.

Description: HAND HOLDABLE TOOL This invention relates to a hand-holdable tool, which may be a writing implement such as a pencil or pen or a different kind of tool such as a scriber or a burnisher for example for use in the application and fixing of dry-transfer lettering. The tool may instead be a scalpel or other kind of surgical instrument or knife such as a craftsman's knife, or a brush such as a toothbrush. Prolonged use of conventional tools such as writing instruments can be tiring for the hand and lead to calluses or writer's cramp or both. Because of the rotationally (and in some cases circularly) symmetrical nature of many writing implements and other tools, the problem is not alleviated by rotating the implement in the hand to another position: the instrument feels just the same. It is to this problem that the present invention is addressed. The present invention provides a hand-holdable tool comprising a functional end and a shaft, the shaft comprising a first portion and a second portion which extends between the first portion and the functional end, the first portion being substantially cylindrical or tapering away from the second portion, and the second portion being substantially frusto-pyramidal and tapering from the first portion to the functional end, a central axis of the first portion being inclined to a central axis of the second portion. The cross-section of the first portion and/or the second portion may be polygon, which may for example have four or eight sides. Edges of the first and/or second portions are preferably rounded. The second portion will be straight or curved whereas the first portion will generally be straight, in a longitudinal sense. The invention therefore encompasses a hand-holdable tool comprising a functional end and a shaft, the shaft comprising a substantially rectangular parallelepipedal portion, whose longitudinal edges are rounded, and a curved substantially frusto-pyramidal portion, whose longitudinal edges are also rounded, tapering from the parallelepipedal portion to the functional end. It will be appreciated that the tool does not possess circular or indeed any rotational symmetry. The position of the tool may therefore be adjusted in the hand to provide fresh points of contact when using the tool, thereby helping to avoid muscular tiredness -and chafing of one particular portion of skin. In one embodiment the tool is a writing implement, in which case the functional end is a marker. The writing implement may be a pencil or crayon: the marker will then be material such as lead, chalk or wax. Alternatively, the writing implement may be a pen, in which case the functional end is an ink bearing tip such as a felt or fibre tip, a nib, a rolling ball or a ball-point. The tool may be partially hollow, possibly by virtue of a bore running its length, particularly when the tool is a writing instrument, in which case the bore may serve to mount the marker. In an important embodiment the tool is a burnisher for dry-transfer lettering or other dry-transfers. In this case, the functional end is a suitably non-abrasive and rounded point which may or may not be (and desirably is not) a marking point. Burnishing is generally carried out twice in the application of dry transfers. First, a carrier sheet bearing a dry transfer is positioned on top of the intended art work. By burnishing the back of the carrier sheet the dry transfer is transferred to the art work. Once the transfer is in place on the art work, it is burnished again to help fix it into position, often with a backing sheet of the dry transfer being interposed between the burnisher and the transferred letter on the art work. The tool may be a knife (in which case the functional end is a blade), and it may be found that the invention has particular application in precision knives, such as scalpels and craftsmen's knives, where it is important that the user has a comfortable grip on the knife, particularly for long periods. Alternatively, the tool may be a brush, in which case the functional end may be a tuft of natural or artificial bristles. As an example, the brush may be a toothbrush; and it may be desirable to form the bristles of nylon or other plastics material. It will be understood that the curved substantially frusto-pyramidal portion will have inner curved surface and an outer curved surface. The radius of curvature of the inner surface may be from 10cm to 5m, for example 70cm to 150cm, with a range of from 80 to 100cm being preferred and about 90cm being typical. The radius of curvature of the outer surface will generally be less than that of the inner and, subject to that proviso, may be from 5 to 50cm, for example from 10 to 25cm, with a range of from 15 to 20cm being preferred and about 18cm being typical. The radius of curvature of the rounded edges need not be the same for each edge. However, it is preferred that each radius of curvature of the rounded edges falls within the range of from 0.5 to 2cm, for example 0.75 to 1.7cm, with about 1cm (+_ 0.4cm) being typical. The width, as perceived when the tool is held in the hand, of the parallelepipedal portion may be from 2 to 3cm, for example from 2.3 to 2.7cm, with 2.4 or 2.5cm being typical. The height of the same portion may be from 1.5 to 2.5cm, with a range of from 1.7 to 2.2cm being preferred and heights of 1.9 or 2.0cm being typical. As a result of the taper, the parallelepipedal portion of the shaft adjacent the functional end may have a rounded square section of from 0.5 to 1.5cm in breadth, with about 1.0cm being typical. The length of the tool may be from 7 to 15cm with 10 to 13cm being preferred and 11 or 12cm being typical. About half of the shaft length may be accounted for by the parallelepipedal portion. The mid-arcs of curvature of the inner and outer surfaces of the curved substantially frusto-pyramidal portion will generally be in a common plane, and that common plane will generally be parallel to and midway between the planes of the sides of the parallelepipedal portion. In a further preferred embodiment, the width of the second portion is from 0.5 to 2cm, preferably from 1 to 1.5cm; and the height of the second portion may be from 0.5 to 2cm, preferably from 1 to 1.5cm. The length of the tool may be from 10 to 15cm, preferably from 10 to 13cm or even from 11.5 to 12.5cm. Approximately one third to one half of the shaft length may be accounted for by the first portion. It may prove to be commercially convenient to provide the shaft separately from the functional end. The shaft therefore can serve as a separate or separable handle. Accordingly, the invention also provides a handle for a hand-holdable tool, the handle comprising a first portion and a second portion which extends between the first portion and the functional end, the first portion being substantially cylindrical or tapering away from the second portion, and the second portion being substantially frusto-pyramidal and tapering from the first portion to the functional end, a central axis of the first portion being inclined to a central axis of the second portion. Pref erred f eatures of the hand l e are as f or the tool itself , mutatis mutandis . For a better understanding of the invention and to show it may be put into effect, reference will now be made by way of example to the accompanying drawing in which: FIGURE 1 shows a back elevational view of a tool in accordance with the invention which is a writing implement; FIGURE 2 shows a side elevation of the tool shown in Figure 1 ; FIGURE 3 shows a longitudinal sectional view taken along the line III-III of Figure 1 ; FIGURE 4 shows a transverse sectional view taken along the line IV-IV of Figure 3; FIGURE 5 shows a bottom plan view of a second tool in accordance with the invention; FIGURE 6 shows a top plan view of the tool shown in Figure 5; and FIGURE 7 shows a side elevational view of the tool shown in Figures 5 and 6. Referring now to the drawings, a hand holdable tool comprises a functional end 3 and a shaft 5. As the tool shown is in fact a pencil, the functional end 3 is the end of a pencil lead 7 extending through a bore 9 in the shaft 5. The shaft 5 has two portions, a substantially rectangular parallelepipedal portion 11, all of whose edges are rounded, and a curved substantially frusto- pyramidal portion 13, again all of whose edges are rounded. The frusto-pyramidal portion 13 can be seen to taper from the parallelepipedal portion 11 to the functional end 3. The flat surfaces of the parallelepipedal portion 11, and in particular the back surface of it, can be used as a burnishing surface. The shaft 5 can be seen to be generally solid, apart from the bore 9, but it may instead be hollow. The shaft may be formed out of, for example, plastics material or wood such as ebony. In alternative embodiments, the functional end may be a rounded point which is suitably non-abrasive, in which case the tool can be used as a burnisher for dry transfers, ' particularly dry transfer lettering. In such a case the shaft 5 may be solid. Alternatively, the pencil lead 7 may be replaced by an ink reservoir and the functional end 3 may be an ink bearing tip in which case the tool functions as a pen. The shaft may comprise holding means such as holes through which may be threaded a cord for supporting the tool round a person's neck. Figures 5, 6 and 7 show a tool 15 which is a second embodiment of the invention. The tool 15 comprises a functional end 17, a first portion 19 and a second portion 21. The first portion 19 tapers slightly away from the second portion 21 , which in turn tapers from the first portion to the functional end 17. A cross section of the tool at any point is octagonal, but the octagon is not regular. A pencil lead 23 may extend through the length of the shaft formed by the first and second portions 19 and 21.

Claims: CLAIMS 1. A hand-holdable tool comprising a functional end and a shaft, the shaft comprising a first portion and a second portion which extends between the first portion and the functional end, the first portion being substantially cylindrical or tapering away from the second portion, and the second portion being substantially frusto-pyramidal and tapering from the first portion to the functional end, a central axis of the first portion being inclined to a central axis of the second portion. 2. A tool as claimed in Claim 1 , wherein the cross- section of the first portion is a polygon. 3. A tool as claimed in Claim 1 , wherein the cross- section of the second portion is a polygon. 4. A tool as claimed in Claim 2 or 3, wherein the polygon is an octagon. 5. A tool as claimed in Claim 2 or 3, wherein the polygon is four-sided. 6. A tool as claimed in Claim 1 , wherein edges of the first and/or second portions are rounded. 7. A tool as claimed in Claim 5, wherein the first portion comprises a substantially rectangular parallelepipedal portion, whose longitudinal edges are rounde . 8. A tool as claimed in Claim 5 , wherein the second portion comprises a curved substantial ly frusto- pyramidal portion, whose longitudinal edges are al so rounded, tapering from the paral lelepipedal portion to the functional end. 9. A too l as claimed in Claim 1 which is a writing implement, and wherein the functional end is a marker. 1 0. A too l as claimed in Claim 9 which is a penci l and wherein the functional end is al l or part of a pencil lead. 1 1 . A too l as claimed in Claim 9 which is a pen and wherein the functional end is an ink bearing tip. 1 2. A too l as claimed in Claim 1 , in which the shaft is partial ly hol low. 13. A tool as claimed in Claim 12, wherein the shaft is solid apart from a longitudinal bore. 14. A tool as claimed in Claim 1 , which is a burnisher for dry transfers, and wherein the end is a non-abrasive rounded point. 15. A tool as claimed in Claim 1, which is a knife. 16. A tool as claimed in claim 15 which is a scalpel. 17. A tool as claimed in Claim 1 which is a brush. 18. A tool as claimed in Claim 17 which is a toothbrush. 19. A handle for a hand-holdable tool, the handle comprising comprising a first portion and a second 5 portion which extends between the first portion and the functional end, the first portion being substantially cylindrical or tapering away from the second portion, and the second portion being substantially frusto- pyramidal and tapering from the first portion to the • j O functional end, a central axis of the first portion being inclined to a central axis of the second portion.

Inventors: LAGERGREN HAKAN, LAGERGREN, HAKAN
Applicants: LAGERGREN HAKAN, LAGERGREN, HAKAN
Application year: 1986
Main classification: B43L15
IPC codes: A46B5, A61B17, B43K23, B44C1