The invention relates to a handle of the kind that is seen in the preamble of claim 1.

The invention thus relates to a tool handle for an elongate part of a tool, the handle comprising an elongate tubular sleeve surrounding the tool part.

Operation with certain types of hand-held tools, for instance in the form of a dentist's drill, have, in certain cases, resulted in problems such as cramp or hand injury, and also to impaired gripping power, in particular when the tool produces or transfers vibrations .

An object of the invention is therefore to provide a han¬ dle, in which one or several of the mentioned drawbacks are entirely or partly obviated.

The object is attained by the invention.

The invention is defined in claim 1.

Embodiments are defined in the dependent claims.

Significant features of the invention are that the handle comprises an elongate tubular sleeve intended to surround a corresponding tool part, that vibration insulation means are provided, for instance a foamed layer of an elastomer that is arranged on the interior of the sleeve to support against the tool, and that a hand-filling body is connected to the sleeve via a flexible elongate element, that has a first of the ends thereof connected to the body and the second end thereof connected to the sleeve.

The proper sleeve may be deformable, suitably elastically deformable, so that it may be threaded up along an elongate angled dentist's drill. Possibly, the sleeve may be pro¬ vided with locking means in order to lock the sleeve axi- ally to the tool part. The locking means may be in the form of a set screw.

The proper sleeve may have an out of round cross section, in particular in an area that is to be surrounded by the gripping fingers of the hand; thumb, forefinger, middle finger, in particular the joints thereof positioned far- thest out. The out of round cross section may advanta¬ geously be substantially triangular and located in the angled area of the hand grip of the dentist's drill and, as indicated, the dentist's drill may be in the shape of an elongate rod that in one end has a chuck for an exchange- able drilling/grinding tool, the rod usually having a con¬ necting energy output line in the second end thereof.

In one embodiment, the flexible connecting element may be in the form of a cord substantially lacking stiffness. In another embodiment, the connecting element may be composed of an readily bendable resiliently elastic spring element, the spring element being mounted to the sleeve in order to carry the body in a preselected position in relation to the sleeve. The spring element may be connected to the body by a ring that is received in a circumference groove on the sleeve and can be rotated around the sleeve, allowing the body to assume a selected position in relation to the sleeve.

As another alternative, the connecting element may be plas¬ tically deformable to allow positioning of the hand-filling body in a selected position by the corresponding bending of the connecting element.

By invention, the user is given the possibility to place the body in a selected position in relation to the sleeve so that the little finger and ring finger of the hand can clamp the body in a selected position in the hand at the same time as the middle finger, forefinger and thumb of the hand grip the sleeve near the machining end ring thereof, the vibration-damping means between the sleeve and the tool part limiting transfer of vibrations from the tool to the hand, especially to the middle finger, forefinger and thumb.

In the following, the invention will be described by way of examples, reference being made to the appended drawing.

Fig. 1 shows a side view of a tool handle.

Fig. 2 shows views from above and below, respectively, of the handle according to Fig. 1.

Fig. 4 shows a view from the front and from behind, respectively, of the handle according to Fig. 1.

Fig. 6 shows schematically a section taken along the line VI-VI .

Fig. 7 shows a variant of the handle.

Fig. 8 shows a section taken along the line VIII-VIII in Fig. 7.

The figures show a handle 1 for a schematically illustrated dentist's drill 20 and comprises an elongate tubular sleeve 2 that extends along a substantial part of a rod-shaped portion of the dentist's drill 2. Such as illustrated in Fig. 1, the rod-shaped body of the dentist's drill 2 is slightly angled in the front portion thereof connected to the drill head 21. The handle sleeve 2 has a generally cir- cular cross section, with the exception of the area of the angled part of the dentist's drill, where the circumference of the sleeve 2 is chamfered for the formation of flat sur- faces 3 extending along the sleeve 2, which surfaces form application surfaces for some of the fingers of the grip¬ ping hand, for instance the thumb and the forefinger, respectively, of the gripping hand. As .an example, a third finger, for instance the middle finger, may rest on the under side of the sleeve in the area of the angled portion of the rod. A rod 5 is shown attached to the sleeve 2 in the longitudinal centre area thereof, and has the first end 51 thereof connected to the sleeve 2 and has the second end 52 thereof connected to a hand-filling body 6, which is shown having globular shape . The shape of the body 6 is not critical, but can be varied in order to present the user a comfortable hand-filling function. The connecting element 5 is flexible to allow the body to be displaced forward rear- ward along the sleeve 2 and also in the circumferential direction in relation to the sleeve 2 into a position where the body 6 conveniently is received in the palm of the user and there is clamped by the little finger and ring finger, at the same time as the thumb, forefinger and middle finger of the same hand grip the sleeve 2 in the area of the cham¬ fers 3. It can be seen, most clearly from Fig. 6, that the chamfers 3 converge towards each other in the direction upwards, while the connecting element 5 extends downward from the sleeve 2. Further, it is seen that the rear end portion of the sleeve 2 has an increasing width in direc¬ tion backwards and in that connection transforms from a circular shape near the connecting element 5, to an oval shape at the rear end of the sleeve 2. The elasticity of the connecting element 5 may involve that the connecting element 5 lacks inherent flexural rigidity and thus func¬ tionally only constitutes an easy bendable cord or the like. In other embodiments, the connecting element 5 may be plastically bendable to allow the body 6 to be displaced to, and stay in, a selected, convenient position.

The connecting element 5 may be selected to afford a selected transfer of vibration energy from the sleeve to the body 6, so that the vibration energy in the sleeve selectably can be distributed to different parts of the hand of the user. Alternatively, the connecting element and/or the body 6 may be formed in order to damp/absorb such vibration.

In yet another embodiment, the connecting element 5 may be resiliently elastic, but have a low flexural rigidity so that upon release, the body 6 is brought back to a rest position of the connecting element 5, while users easily can bend the resiliently elastic connecting element 5 in order to place the body 6 in a selectable position in rela¬ tion to the sleeve.

Fig. 7 illustrates an embodiment of the connection of the connecting element 5 to the sleeve 2, and Fig. 8 shows a section taken along line VIII-VIII in Fig. 7. From Figs. 7 and 8, it is seen that the sleeve 2 has a circumferential groove 14 receiving an assembling loop 15 that is received in the groove 5 and is provided with the flexible element 5. The loop 15 is shown to be in the shape of a partial ring that grips around more than 180° of the sleeve 2 in the groove 14 and that is rotatable around the groove 14 to allow selectable adjustment of the end 51 of the fastening element in relation to the sleeve 2.

From Fig. 6, further it is seen that the sleeve 2, in the interior thereof, is provided with a coating 9 of a foamed plastic material, preferably an elastomer. The layer 9 serves to limit the transfer of vibrations from the tool 2 to the hand that grips the outside of the sleeve 2. The layer 9 may also serve to retain the sleeve 2 on the tool 20 by means of friction. Naturally, the layer 9 does not need to extend all over the inner surface of the sleeve 2. In a modification, not described in detail, the proper sleeve 2 may be formed of a material having a relatively high capability of damping vibrations from the tool 2, wherein the sleeve may lie in direct contact with the tool. The material of the sleeve may then have a relatively high internal friction. The sleeve 2 may also be composed of a bendable material so that the sleeve 2 can be manufactured in a straight generally tubular state, but can be bent in connection with threading onto a tool-rod portion in order to conform to a bent portion of the rod part .

By the handle according to the invention, improved gripping ergonomics of the tool is attained, and among other things, the risk of cramp in the hand and vibration injuries ("white fingers") is limited.