WO2000067955A1

WO2000067955A1 - Jig for holding a chuck key

Info

Publication number: WO2000067955A1
Application number: PCT/GB2000/001592
Authority: WO
Inventors: Frederick Haley Russell
Original assignee: Chuck-Lok New Zealand Ltd.
Priority date: 1999-05-06
Filing date: 2000-05-05
Publication date: 2000-11-16
Also published as: AU4420500A; GB9910452D0

Abstract

A jig (1) for positively holding a chuck key (2) in mesh with a chuck (3), comprising a body (4) having an aperture (5) adapted snugly to receive the chuck body whereby the jig (1) is mounted on the chuck, means (7) on the body locating the shaft of a toothed chuck key and shoulder means (11) preventing axial displacement of the chuck key away from the chuck body to hold the teeth on the chuck key in engagement with corresponding teeth on the chuck.

Description

TITLE :

JIG FOR HOLDING A CHUCK KEY

DESCRIPTION

TECHNICAL FIELD The invention relates to hand tools and more particularly to hand tools employing tool holders of t_he kind known as a "Jacobs" chuck.

BACKGROUND ART A "Jacobs" chuck is used in a drill or the like to hold a drill bit or the like in the drill, and comprises a body housing a set of sliding jaws which are moved radially by relative rotation between the body and a concentric ring on the body. Usually the ring is formed with gear teeth and the body is formed with a socket for receiving an end of a toothed key which, when engaged with the socket and with the teeth on the ring, is rotated to tighten the sliding jaws on to the drill bit. On the completion of a drilling operation the key may be re-engaged with the teeth on the ring and rotated in the reverse sense to slacken the jaws to allow removal of the drill bit.

It is well known that it is often difficult sufficiently to tighten such a chuck as to prevent the drill bit from slipping in the chuck, especially when dealing with small hand tools, e.g. of the nature of domestic so-called 'do-it-yourself or D-I-Y' electric hand drills and the like, although the problem is also present to some extent with larger workshop equipment such as industrial hand drills, pillar drills, mill-drills, etc. Often during tightening of the chuck, the key will become partially disengaged and damage the key or chuck. The problem is worse where the user has limited hand strength. It is an object of the invention to provide a simple device for alleviating this problem.

DISCLOSURE OF INVENTION

According to the invention, there is provided a jig for positively holding a toothed chuck key in mesh with a toothed chuck, the jig comprising a body having mounting means for mounting the jig on the chuck, locating means on the body for locating the chuck key relative to the chuck and shoulder means preventing axial displacement of the chuck key away from the chuck body and holding teeth on the chuck in engagement with corresponding teeth on the chuck key.

The toothed chuck may be a "Jacobs" chuck. The means for mounting the jig on the chuck is preferably releasable so that the jig may be applied temporarily to the chuck during tightening or loosening of the chuck. The mounting means may be in the form of an aperture in the jig body, the aperture being adapted to receive snugly a portion of the chuck. The aperture may be in the form of a generally cylindrical through-bore. The diameter of the bore may be adjusted to match the diameter of the portion of the chuck to be received therein. The portion of the chuck received in the aperture may be a nose portion from which a set of jaws projects.

The chuck key comprises a shaft and a toothed head attached to the shaft. The locating means may be in the form of a generally semi-circular recess in the jig body for snugly receiving the shaft of the chuck key. The locating means may further comprise a second generally semi-circular recess for snugly receiving the toothed head of the chuck key. The dimensions of the recesses may be chosen to match the dimensions of the shaft and toothed head. Thus, the dimensions of the jig may be chosen to fit a particular chuck. Similarly, the shape of the jig may be chosen to be a convenient shape, for example, for ease of manufacture or to fit a particular chuck. For example, the jig may be rectangular, circular or hexagonal etc. The axes of the semi-circular recesses may be normal to the axis of the generally cylindrical through-bore. The shoulder means may be formed by the junction between the two recesses. The jig may be made of plastics, for example, polypropylene or nylon. The plastics may be fibre- reinforced, e.g. glass-filled. The jig may be injected moulded. The body of the jig may further comprise a through- bore through which means, in the form of a lace, string or wire, are fed to attach the jig to the chuck or a tool comprising the chuck to prevent the jig from being mislaid. The bore may be tapered, counter-bored with stepped diameters or parallel-bored.

BRIEF DESCRIPTION OF DRAWINGS

The invention is diagrammatically illustrated, by way of example, in the accompanying drawings, in which :-

Figure 1 is a plan view of a jig according to the invention;

Figure 2 is an end view of the jig of Figure 1;

Figure 3 is a cross-section on the line A-A of Figure 1, and

Figure 4 is a sketch, partly in cross-section showing a Jacobs chuck with a chuck key engaged and with the jig of the present invention engaged with the chuck and key to hold the two in mesh during operation of the key.

BEST MODES FOR CARRYING OUT THE INVENTION

In Figure 4, there is shown a jig (1) for positively holding a chuck key (2) in mesh with a Jacobs-type chuck (3). The chuck key (2) comprises a shaft (8) and a toothed head (13) on which teeth (12) are mounted. The chuck (3) comprises a body (20) comprising teeth (15), a nose portion (6) and a set of sliding jaws (21) projecting from the nose portion. Cylindrical recesses (14) are formed in the nose portion (6) . In use, the chuck key engages with one of the recesses (14) and the teeth (12) on the toothed head (13) of the chuck key (2) engage with the teeth (15) on the chuck (3) . The jig (1) is positioned over the chuck (3) to prevent relative movement of the chuck (3) and chuck key (2) and to hold the teeth (15,12) on the chuck and key in mesh during tightening or loosening of the chuck.

Figures 1 to 3 illustrate the features of the jig (1) which comprises a generally rectangular body (4). having an aperture (5) in the form of a through bore adapted snugly to receive the nose portion (6) of the chuck whereby the jig (1) can be temporarily mounted on the chuck. The diameter (16) of the aperture (5) is chosen to match the diameter of the nose portion (β) of the chuck. The body (4) of the jig is also formed with two part- cylindrical recesses (7,10). The first recess (7) locates and snugly receives the shaft (8) of the chuck key (2) and the second larger recess (10) locates and snugly receives the teeth (12) and the toothed head (13) of the chuck key (2) . The diameter (18) of the recess (7) is chosen to match the diameter of the chuck shaft (8) . The length (17) of recess (10) is chosen to match the length of the teeth (12) and head (13) . The two recesses (7,10) are aligned, adjacent and separated by shoulder means (11) to engage the chuck key (2) and to prevent axial displacement of the chuck key away from the chuck body to hold teeth (12) on a toothed head (13) on the chuck key in engagement with corresponding teeth (15) on the chuck.

The jig (1) is made of plastics, e.g. polypropylene or nylon but could be made of other materials, e.g. steel, cast iron, aluminium alloy. The jig and key are, of course, removed during use of a tool (not shown) held in the chuck. However, to prevent the jig (1) being mislaid, the jig (1) may be attached to the tool via a lace or string (not shown) fed through a tapered bore (19) in the body (4) of the jig (1).

INDUSTRIAL APPLICABILITY

The invention thus provides a simple jig tool which may be applied temporarily to a Jacobs-type chuck to facilitating use of the chuck during the tightening or loosening operation.

Claims

CLAIMS 1. A jig for positively holding a toothed chuck key in mesh with a toothed chuck, the jig comprising a body having mounting means for mounting the jig on the chuck, locating means on the body for locating the chuck key relative to the chuck and shoulder means preventing axial displacement of the chuck key away from the chuck and holding teeth on the chuck in engagement with corresponding teeth on the chuck key.

2. A jig according to claim 1, wherein the mounting means is in the form of an aperture in the body, the aperture being adapted to receive snugly a portion of the chuck.

3. A jig according to claim 2, wherein the aperture is in the form of a through-bore.

4. A jig according to claim 3, the through-bore is generally cylindrical.

5. A jig according to claim 3 or claim 4, wherein the portion of the chuck received in the aperture is a nose portion.

6. A jig according to any preceding claim, wherein the chuck key comprises a shaft and a toothed head attached to the shaft and the locating means is in the form of a recess in the jig body for snugly receiving the shaft of the chuck key.

7. A jig according to claim 6, wherein the recess is generally semi-circular.

8. A jig according to claim 6 or claim 7, wherein the locating means further comprises a second recess for snugly receiving the toothed head of the chuck key.

9. A jig according to claim 8, wherein the second recess is generally semi-circular.

10. A jig according to claim 8 or claim 9, wherein the 5 shoulder means is formed by the junction between the two recesses .

11. A jig according to any one of claims 8 to claim 10, wherein the axes of the recesses are normal to the axis of the through-bore.

10 12. A jig according to any preceding claim, wherein the jig is made of plastics.