GB2374822A

GB2374822A - Spanner

Info

Publication number: GB2374822A
Application number: GB0208033A
Authority: GB
Inventors: Jonathan Charles Elliott
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-04-09
Filing date: 2002-04-08
Publication date: 2002-10-30
Also published as: GB0208033D0; GB0108954D0; GB0205665D0

Abstract

A spanner for a screw threaded or other fitting such as a bush for an electrical conduit having an internal bore and external flats is disclosed, the spanner head 12 having three or more projections 18, 20, 22 which define between them a pair of gaps 24, 26, each of which is adapted to receive a portion of the fitting (28 fig 3) between one of the flats 32 and an adjacent region of the bore (30 fig 3) of the fitting, whereby turning of the spanner results in turning of the fitting around the axis of the bore. Each of the gaps is sized so as to provide a close fit when in place over the flat and bore of the bush. In order that the spanner can accommodate awkward angles, it is preferred that the spanner head 12 is connected to an elongate handle 14 via at least one pivot means 16. Alternatively, the spanner head 12 may be provided with means (36 fig 3) for connection to a standard socket set bar or handle, preferably via universal joint connector.

Description

SPANNER This invention relates to a spanner and more particularly relates to a bush spanner. Bushes are commonly used in electrical installations where they may connect a conduit which is for carrying electrical wires to an enclosure such as a wiring box or trunking. The electrical conduit is fitted to the bush and the bush has an external thread which engages a threaded portion of the enclosure, or a nut may be used to secure the bush to the enclosure.

Conventionally, open ended spanners are used to tighten these bushes, but such spanners suffer from the drawback that if access to the bush is such that the spanner head cannot be laid flat, then it becomes difficult to turn the spanner. Also, the bush often needs to be installed close to a wall of the enclosure, with the result that the wall obstructs the spanner.

Ring spanners suffer from a similar drawback in that the spanner must be laid substantially flat in order to engage the bush and this may not be possible. Furthermore, there must be clearance around all of the flats of the bush in order for a ring spanner to be placed over it. Similar comments apply to a socket spanner set.

The present invention seeks to provide a bush spanner improved in the above respects.

According to the present invention, there is provided a spanner for a screw threaded or other fitting having an internal bore and external flats, the spanner having three or more projections which define between them a pair of gaps, each of which is adapted to receive a portion of the fitting between one of the flats and an adjacent region of the bore of the fitting, whereby turning of the spanner results in turning of the fitting around the axis of the bore.

Preferably, each of the gaps is sized so as to provide a close fit when in place over the flat and bore of the bush.

In order that the spanner of the invention can accommodate awkward angles, it is preferred that the spanner head is connected to an elongate handle via at least one pivot means. Alternatively,

the spanner head may be provided with means for connection to a standard socket set bar or handle, preferably via universal joint connector.

Preferably, the two gaps defined by the projections engage flats which are diametrically opposite one another on the bush. This form of location provides excellent grip and yet with the projections of the invention locating on the bush vertically (i. e. parallel to the bush axis), rather than horizontally (i. e. transverse to the bush axis) as with a conventional spanner, the head takes up very little space and can therefore be got into confined spaces where a conventional spanner will not fit.

The invention will be described further, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side elevational view of a spanner in accordance with the invention; Figure 2 is a similar view to Figure 1 with the spanner rotated through 90 : and Figure 3 is a view, on an enlarged scale, of the spanner head locating with the bush.

Referring to the drawings, and in particular Figures 1 and 2, a spanner in accordance with the present invention generally designated 10 comprises one or more heads 12. 12' each attached to a handle or bar portion 14 via a pivot 16. The heads 12, 12' can swivel virtually 1800 with respect to the bar 14.

The head 12 comprises three projections 18,20, 22 which between them define two gaps 24,26. The head 12'is constructed in a similar manner, but may be of a different size so as to fit a different sized bush. The most commonly used bushes are 20mm and 25mm, and each of the heads may conveniently be sized so as to fit one of these bush sizes.

As can be seen from Figure 3, the head 12 may co-operate with a bush 28 having an internal bore 30, flats 32 and a threaded portion 34. This is a standard male electric box/conduit connecting bush having six flats in a hexagonal arrangement at the top of the bore which carries the external thread. The gaps 24,26 fit over a pair of diametrically opposed flats 32 with the

central raised portion 20 locating within the internal bore 30 of the bush 28. As can be seen, the spanner head 12 locates parallel to the axis of the bush 28 rather than transverse to it as would be the case with a conventional spanner. This grips the bush 28 securely and enables it to be tightened or untightened and yet the head 12 takes up very little space and can be inserted into awkward corners and confined spaces. The presence of the pivot joint 16 enhances the ability to operate in tight spaces.

As illustrated in 23, the bush head 12 is not connected to a handle or bar 14, but instead has a standard"socket"square connector 36 for connecting onto a bar, swivel bar or standard socket set drive. Preferably, it connects to a socket set drive via at least a swivel or preferably a universal joint to maintain the flexibility of use in confined spaces.

The spanner of the invention is extremely simple in design, and is therefore economical to manufacture, but is extremely effective in practice.

Claims

CLAIMS 1. A spanner for a screw threaded or other fitting having an internal bore and external flats, having a head with three or more projections which define between them a pair of gaps, each of which is adapted to receive a portion of the fitting between one of the flats and an adjacent region of the bore of the fitting, whereby turning of the spanner results in turning of the fitting around the axis of the bore.
2. A spanner as claimed in claim I wherein each of the gaps is sized so as to provide a close fit when in place over the flat and bore of the bush.
3. A spanner as claimed in either of claims 1 or 2 wherein the spanner head is connected to an elongate handle via at least one pivot means.
4. A spanner as claimed in either of claims 1 or 2 wherein the spanner head is provided with means for connection to a standard socket set bar, handle or drive.
5. A spanner as claimed in any of claims 1 to 4 wherein the two gaps defined by the projections in use engage flats which are diametrically opposite one another on the fitting.
6. A spanner as claimed in claim 3 having two heads, one at either end of the handle.
7. A spanner as claimed in claim 6 wherein the respective heads have different sized and spaced gaps so as to fit different sized fittings.
8. A spanner substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2, and Figure 3 of the accompanying drawings.