GB2109527A - Electric battery torch - Google Patents

Abstract

A pencil or pen type torch having a slim hollow body (10) containing batteries (16a, 16b) arranged end to end and separated by a resilient spacer element (22) which is compressible by means of a push- button (24) to establish a circuit through the batteries and the lamp completed by way of a conductor strip of foil (19) engaging the metallic cap (14) of the lamp and bent inwardly at its opposite end to engage contact (18b) provided by the lower end of the metallic body of battery (16b). Push- button (24) has a helical cam surface (28) cooperating with a helical cam surface (29) on end cap (25) to enable the torch to be maintained in the switched on condition by rotation of the push-button. <IMAGE>

Description

SPECIFICATION Improvements relating to electric torches This invention relates to an electric battery torch (hereinafter referred to as being of the kind specified) comprising a hollow elongate body for containing a battery having contacts at each end, said body being of slim transverse cross-sectional dimensions suitable for carrying upright in the breast pocket of a garment such as a jacket, shirt, blouse or the like, or in a similar interior pocket, whether or not the body is provided with an exterior clip, a lamp carried by the body at one end, conductor means for completing a circuit between the lamp and the battery terminals, and switch means for controlling the current in the circuit. Torches of the kind specified are often called pen or pencil type torches, for the reason that they are of similar dimension as regards length and transverse cross-sectional dimensions.

Typically when the body is of circular form in transverse cross-section the diameter would be in the range 9 mm to 15 mm.

The invention has been developed primarily in relation to torches of the kind specified which are commonly called "disposable" meaning that the body is formed or constructed so that it does not provide for removal of the battery and so when the latter is exhausted the user is intended to throw the torch away and purchase another.

One of the problems which exists in torches of the kind specified is that, because of the slim transverse cross-sectional dimensions, there is little or no space to accommodate a conventional switch which would comprise a conductor strip extending longitudinally through the interior of the body and slidable lengthwise by means of a finger piece accessible through an aperture in the side of the body, one end of the conductor strip being connected electrically to the contact at the end of the battery remote from the lamp, and the other end of the strip alternatively engaging and being separated from a metallic lamp holder or a metallic end cap of the lamp itself.

Moreover, a conventional switch entails the provision of a significant number of component parts, shaping of the latter to provide guidance for the sliding movement, and assembly in the body in the proper relation to the finger piece aperture, all of which operations contribute significantly to the cost of manufacture to an extent which would be unjustifiable for a disposable torch.

Whilst the present invention is intended to eliminate these disadvantages relative to disposable torches, it may nevertheless be applied to a non-disposable torch of the kind specified.

According to the invention a torch of the kind specified is provided wherein the switch comprises contacts situated at one end of the battery, and maintained in separated relation by an elastically deformable electrically nonconducting spacer element between such contacts while permitting the contacts to engage each other when appropriate deformation of the spacer element occurs, and operating means for bringing about said deformation.

The contacts may both be elements of the circuit which are structurally separate from the battery. Preferably, however, at least one and possibly both of the contacts may be constituted by a contact of the battery, or respective contacts of adjacent series connected batteries.

It would be within the scope of the invention for the spacer element to be provided at either end of the battery between the battery contact situated thereat and the adjacent component of the circuit, for example a conductor strip at the end of the battery remote from the lamp or the lamp contact itself.

In a preferred arrangement, however, the torch, when in use, contains at least two batteries each having contacts at their opposite ends and arranged in longitudinal succession in the body, and wherein the spacer element is interposed between adjacent ends of the batteries or two of same.

A simple and effective form of spacer element is a piece of elastically deformable electrically non-conductive material having an aperture extending through it longitudinally of the body, through which aperture the contact can be brought into engagement with each other.

Whilst various forms of operating means may be provided, for example a deformable end wall portion at the end of the body opposite that at which the lamp is carried, the preferred form of operating means comprises a push-button extending through an opening in the body at its end opposite to the lamp.

The invention will now be described, by way of example, with reference to the accompanying drawing showing one embodiment of the invention in longitudinal and diametral crosssection.

In this embodiment the torch is of the disposable type and comprises a body 10 of a suitable plastics material, such body being of circular cross-section and having an external diameter of about 1 3 mm, a wall thickness of about 1 mm and an overall length of about 125 mm.

The body is open at one end 11 and contains an electric lamp 12 which may be of the type in which the glass envelope includes a lens portion 13. The lamp includes a metallic cap 14 which is screw-threaded externally and which cooperates with an integral rib 1 5 provided internally of the body to secure the lamp in position, preferably with its lens portion 1 3 level with, or just inside, the end 11.

For supplying power the torch body contains two batteries 1 spa, 1 6b which have projecting contacts 1 7a, 1 7b at their upper ends as seen in the drawing, and contact 1 8a, 1 8b afforded by exposed metallic end faces of the battery bodies.

A conductor strip 1 9 such as a piece of aluminium foil of a few thousandths of an inch thick, say 0.075 mm, extends longitudinally of the body internally thereof and may, if desired, be adhesively secured to the body surface. At its end 20 it is maintained in contact with the metallic cap 14 of the lamp being trapped between the rib 15 and the cap, in addition to possible adhesive securement to the body, while its end portion 21 is bent over towards the centre of the body to lie against the contact 1 8b of the battery 1 6b. Where it extends alongside the batteries 16a, 16b the strip 1 9 is insulated from the metal bodies of the batteries by a coating of insulating material on the batteries themselves such as a paper casing 32a.

The circuit comprising the lamp, the conductor 1 9 and the two batteries 16a,16b includes a switch constituted by the contact 1 8a and the contact 1 7a which are normally maintained separated from each other by a spacer element 22. This is made of a material selected to have a sufficient degree of resilience naturally to hold the contacts 1 Sa, 1 7a but capable of being deformed by compression longitudinally of the body under finger pressure to allow these contacts to engage each other through a central aperture 23 extending longitudinally through the spacer element. Foamed or sponge rubber or a plastics material is suitable.

As seen, it has the form of a bush or washer, the outer diameter being such as to be a close fit in the interior of the torch body, and the diameter of the aperture 23 being such as to expose the whole of the contact 1 7a.

To enable the requisite finger pressure to be exerted, a finger piece or push-button 24 has a stem extending through an aperture in end cap or end wall 25 of the body. At its inner end the pushbutton 24 includes a piston-like head 26 which engages the end portion 21 of the conductor strip to hold this in electrically conductive relation with the contact 1 8b. At its underside the head 26 is formed to present a heiical cam face 28 having a step 27, and the end cap 25 at its interior side is also shaped to present a complementary helical cam face 29 with a step 30.Rotation of the stem of the push-button 24 to move the steps towards each other, or in the limit to bring them into contact, will cause the higher parts of the cam faces to be axially opposite to each other and provide sufficient axial movement of the battery 1 6b towards the battery 1 6a to deform the spacer element 22 and establish electrical conduction between contacts 1 7a and 1 8a. The angle of the cam faces is such that the parts are then retained in this position.

Alternatively, if the torch is required to be switched on only momentarily, the push-button 24 is not rotated but is simply pressed in an axial direction.

The body may be provided with a clip arm 31 to enable the torch to be clipped onto a breast or interior pocket as desired.

It would of course be possible, if a single battery were used or in any event, to provide the spacer element at the upper end of the uppermost battery or at the lower end of the lowermost battery, but in the latter case the end portion 21 would then require to be provided with a protruding contact equivalent to the contact 17a.

Either of these arrangements may be adopted where the torch in use contains a single battery.

Instead of making use of a battery contact or contacts of respective batteries as the switch contacts, it would be possible to provide a switch contact in its own right or two such contacts, e.g.

a flanged thimble-shaped piece of metal with the flange lying face to face with one face of the spacer 22, and the "pip" or "projection" extending into the aperture 23 for engagement under compression of the spacer with a component of the circuit present at the opposite face or with a similar thimble-shaped piece projecting into the aperture from the opposite face of the spacer.

Further, the end cap 25, instead of being fixed permanently in position or made integral with the remainder of the body 10, may be removably secured in position, e.g. by screwed engagement with the remainder of the body where it is required to provide for removal and replacement of the battery or batteries as in a non-disposable torch.

Claims (4)

1. A torch of the kind specified wherein the switch comprises contacts situated at one end of the battery, and maintained in separated relation by an elastically deformable electrically nonconducting spacer element between such contacts while permitting the contacts to engage each other when appropriate deformation of the spacer element occurs, and operating means for bringing about said deformation.

2. A torch according to claim 1 wherein at least one of the contacts comprises a contact of the battery.

3. A torch according to claim 2 wherein the torch, when in use, contains at least two batteries each having contacts at their opposite ends and arranged in longitudinal succession in the body, and wherein the spacer element is interposed between adjacent ends of the batteries or two of same.

4. A torch according to any one of the preceding claims wherein the spacer element is a piece of elastically deformable electrically nonconductive material in the form of a bush or washer having an aperture extending through it longitudinally of the body, through which aperture the contacts can be brought into engagement with each other.

4. A torch according to any one of the preceding claims wherein the spacer element is a piece of elastically deformable electrically nonconductive material having an aperture extending through it longitudinally of the body, through which aperture the contacts can be brought into engagement with each other.

5. A torch according to any one of claims 1 to 4 wherein the operating means comprises a pushbutton extending through an opening in the body at its end opposite to the lamp.

6. A torch according to claim 5 wherein the push-button is provided with means to retain it in a "lamp on" position.

7. A torch according to any one of the preceding claims wherein the conductor means comprises a strip of electrically conductive foil extending internally of the body from one end to the other end alongside the battery when the latter is in position in the body and in electrical contact with the lamp at one end of the body and a battery contact at the other end of the body.

8. A torch substantially as herein described with reference to and as shown in the accompanying drawings.

New claims or amendments to claims filed on 16th August 1982.

Superseded claims 1 and 4.

New or amended claims:

1. A torch of the kind specified wherein the switch comprises contacts situated at one end of the battery, and maintained in separated relation by an elastically deformable spacer element of electrically non-conducting material between such contacts while permitting the contacts to engage each other when appropriate deformation of the spacer element occurs, and operating means for bringing about said deformation.