CA1182668A

CA1182668A - Screwdriver

Info

Publication number: CA1182668A
Application number: CA000383262A
Authority: CA
Inventors: Rudolph Talamantez
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-08-08
Filing date: 1981-08-05
Publication date: 1985-02-19
Also published as: EP0045936A1; ES268577Y; KR830005973A; KR850001082B1; ES268577U; JPS5761474A

Abstract

ABSTRACT OF THE INVENTION

A tool having a handle with a shaft projecting end and a shaft projecting therefrom, characterized by the handle along at least a portion of its length having a cross-section which increases in area in a direction toward the shaft projecting end of the handle, the handle having a length portion thereof of uniform cross-sectional area from an end thereof opposite its shaft projecting end to its increasing cross-sectional length portion.

Description

SCRE~ DR LVER
FIELD OF THE INVENTIO~
.
This invention relates to a screwdrlver of improved construction.
DESCRIPTION OF THE PRIOR ART
Screwdrivers are tools which are extensively used. Generally, the tool comprises two parts, a screw-driving shaft and a handle. The shaft is intended to fit in~o a screw head slot while the handle is the means by which the desired torque is applied to the shaf~ to loosen or tighten a screw. When using the tool to tighten or to loosen a screw, two forces are applied, one axially for keeping the screwdriving shaft engaged in the screw slot and the other rotationally to turn the tool~ Should the shaft slip from the slot when applying these two orces, the screw slot may become so damaged that further screwing or unscrewing operations become difficult, if not impossible.
In some cases the screw head may even break thus complicating even more the screwing or unscrewing task~
A problem with prior screwdrivers is that they provide gripping handles with which it is difficult to develop the two forces referred to unless the sh~ft of the screwdriver is made extremely long. Space limitations however often make it difficult to use such long screwdrivers.
The objective -therefore of this invention is to provide a screwdriver capable of developin~ the required forces to ease removal or tightening of screws and oLher devices rotatable by means of a screwdriver withou~ s~ripping or marring the head of the device acted on, This objective is attained by the invention by providing a screwdriver %6~8 having a handle which enables joint application of sufficient torque and inward axial force to facilitate screwing and unscrewing operations while minimizing risk of damage to the device being screwed or unscrewed.
UMMARY_OF THE IN~ENTION
With the foregoing in mind we provide in accordance with the invention a tool having a handle with a shaf-t projecting end and a shaft projecting therefrom, characterized by the handle along at least a portion of its length having a cross-section which increases in area in a direction toward the shaft projecting end of the handle, the handle having a length portion thereof of uniform cross-sectional area from an end thereof opposite its shaft projecting end to its increasing cross-sectional length portion.
By virtue of the screwdriver handle in accordance with the invention, the amount of axially applied force, i.e. in the direction of the shaft, as well as the turning torque that can be developed in rotation of a screw or the like by means of the screwdriver shaft is greatly increased.
As a result of the invention increased forces alang the shaft and turning torque may also be developed for small screwdrivers. Also, one is capable with the present invention of providing greater forces along the shaft and turning torque within confined spaces-BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an isometric elevational view of a screwdriver in accordance with one embodiment of the invention;
Figure 2 is a side view of the screwdriver of Figure 2, Figure 3 is a cross-sectional view of Figure 2, Figure 4 is a side view of a screwdriver in accordance with a second embodiment of the inven-tion;
Figure 5 is a cross-sectional view of the embodiment of Figure 4, and Figure 6 is a view taken along the line 6-6 of Figure 4.
1~

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DES~,RIPTION OF THE PR~FERRED EMBODIM~N'r Figures 1 through 3 show a first embodiment of a screwdriver in accordance with the present invention.
The screwdriver includes a handle 1 having a cylindrical shaped end portion 3 and a frustoconically shaped handle portion 5 at the for~ard or shaft projecting end of the handle Grooves 7 are helical:Ly provided in the handle for improved gripping. A screwdriver shaft 9 is secured within the handle l in known manner~ The screwdriver in the embodiment of Figures 1 through 3 is operated by grasping the handle 1 in the region 5 so that substantially greater forces axially along the shaft and turning torque are applied than would be the case i:E the screwdriver were held in its cylindrical region. This is true because, considering the cylindrically shaped handle, the operator has inadequate surface upon which to apply longitudinally directed forces. The frustoconical handle portion of Figures 1 to 3 provides the operator with a surface ~gainst which he can bear without hand slippage so that substantial forces may be applied not only axially but also rotationally about the shaft~
In the embodiment of Figures 4 through 6, the handle can be made of plastic and molded in the shape s~own~
The handle includes the frustoconical polygonal portion ll and the cylindrical portion 13 wîth a shaft holder 15 secured in the handle for threadedly receiving the shaft 17 or in other kno~n manner~ The longitudinal ribs 19 serve the same purpose as the grooves 7 in the embodiments of Figures 1 through 3~ It can be seen that the shaft insert 21, by being threadable, is capable of securing a two-ended shaft having a different size or type of end portion at either end of the shaft to supply two siæes or types of screwdriver~ This i5 accomplished by merely unthreading the shaft from the handle and reinserting ~t after turning it 180, Alternatively, the portion of the shaft shown near the free end of the cylindrical portion o~ the handle can be secured within a small thickness, longltudinally extending, slo~ to prevent ro~ation of the shaft within the handle. To secure the shaft within the handle, the shaft insert 21 may be held in place by a spring clip part 23~ A molcled axially directed pocket 25 is provided to afford storage of ~he shaft 17. The annularly arranged pockets 27 are provided to decrease weight and for conservation of plastic material. The rib portions 29 best shown in Figure 6 define the pockets 27 and provides stiffening for the handle portion oE the increasing cross sectional area.
It can be seen from the foregoing, the invention provides great advantages over prior screwdri.vers in that a great deal more force along the shaft as well as torque can be applied to a device to be screwed or unscrewed~
The specific embodiments herein described are ~erely exemplary and hence variations and modifications made by those skilled in the art are intended to be covered, the scope of the invention being detel~ined by the appended claims~

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A tool having a handle with a shaft projecting end and a shaft projecting therefrom, characterized by the handle along at least a portion of its length having a cross-section which increases in area in a direction toward the shaft projecting end of the handle, said handle having a length portion thereof of uniform cross-sectional area from an end thereof opposite its shaft projecting end to its increasing cross-sectional length portion.

2. The tool of claim 1, characterized in that the handle has a shape which is symmetrical about its longitudinal axis.

3. The tool of claims 1 or 2, characterized in that said increasing cross sectional length portion uniformly increases in cross-sectional area.

4. The tool of claim 1, characterized in that said uniform cross-sectional length portion of the handle has a cylindrical shape and said increasing cross-sectional length portion of the handle has a generally frustoconical shape of circular or polygonal cross-section.

5. The tool of claim 2, characterized in that said uniform cross-sectional length portion of the handle has a cylindrical shape and said increasing cross-sectional length portion of the handle has a generally frustoconical shape of circular or polygonal cross-section.

6. The tool of claim 3, characterized in that said uniform cross-sectional length portion of the handle has a cylindrical shape and said increasing cross-sectional length portion of the handle has a generally frustoconical shape of circular or polygonal cross-section.

7. The tool of claims 4, 5 or 6, characterized in that the polygonal cross-sectional length portion of the handle includes annularly arranged pockets defined by rib portions, said shaft projecting from the shaft projecting end of the handle centrally of said annularly arranged pockets.