US2347482A - Electric torch - Google Patents

Description

April 25, 1944. D. KARO 2,347,4 2

ELECTRIC TORCH Filed March 10, 1943 F/G. F/GZ /O5\ I04 Invenldr A tlornev Patented Apr. 25, 1944 UNITED ELECTRIC TORCH David Karo, London, England Application March 10, 1943, Serial No. 478,710 In Great Britain April 8, 1942 1 Claim.

This invention relates to dimming devices for use in electric torches and the like, and it has for its object to provide a form of resistance which can be included in the circuit between the battery and the lamp bulb to enable the amount of light emitted to be cut down as desired without the necessity for employing layers of paper or other semi-transparent material. It will be evident that there is a substantial economy in using a resistance in series between the battery and the filament which cuts down the current instead of using the full current and merely cutting down the light emitted.

If the resistance element is made small enough so that two or more of these elements can be included in series with a new battery, they can be taken out one by one as the battery weakens during use, so enabling the battery to be employed for as long as it will give enough current to light a lamp.

Each resistance element may be made as a small and thin unit which can either be incorporated in the sleeve of the battery at the top or bottom or placed as a separate elementin the torch in the battery circuit. The element can be made small and thin by winding a few turns of resistance wire on a slip of cardboard or other insulating material, and applying over this at the back and front other layers of insulating material each with a terminal strip whereby contact can be made with the battery on the one hand and a part of the torch on the other hand.

One form of resistor according to the invention is shown by way of example in the accompanying drawing, in which Figure 1 illustrates one form of resistor element in the form of a small disc shaped unit;

Figure 2 is an edge view of the device of Figure 1; and

Figures 3 and 4 are detail views of parts used in the construction of the resistor of Figures 1 and 2.

Figures 1 to 4 show a resistance unit which can be made up for insertion between either end of a battery and the part making contact with it in a torch, the unit being made thin so that two or more such units can be slipped into a torch when required to vary the circuit resistance. The thicknesses are exaggerated for clearness in Figure 2.

Figures 1 and 2 show the completed article.

Figure 3 shows a strip of cardboard or other insulating material I04, notched at its edges and having a resistance wire Hi5 wound upon it. Only a couple of turns of this wire are shown in Figure 3, but any number of turns may be accommodated as required. The element I04 is then placed between two thin cardboard discs I06, Figure 4, these discs being placed in opposite positions with their tabs I91 projecting at opposite sides. The strip IM and the discs I86 have holes in them at H18, and when assembled eyelets are passed through these holes carrying also metal tongues I09, the eyelets being rivetted over to hold the parts together. The tabs I01 are folded over the heads of the eyelets and under the tongues I09, as seen in Figure 1, so that there is one tongue exposed together with its associated eyelet at either side of the element.- The ends of the resistance wire I05 are looped round the eyelets so that the current passes from one eyelet to the other through the resistance wire I05.

The separate resistance unit such as is shown in Figures 1 to 4 has thevadvantage that it can be inserted in any electric torch between existing contacts without any modification of the normal construction, and by using-two or three such units, each of a small resistance value, it is possible to make the resistance variable in steps by putting in or taking out one or more such elements as required. The resistance elements may be made up to any shape depending on the type of torch and battery with which they:are to be used.

I claim:

A dimming resistance element for flash lights comprising an insulating support, a length of resistance wire wound on such support, eyelets to which the ends of said resistance wire are connected, two insulating layers held in place over the two sides of said resistance wire by said eyelets, terminals secured at the outside each on one of said eyelets, and tabs on each of said insulating layers each turned back over the end of one eyelet and tucked under one of said terminals on another of said eyelets.

DAVID KARO.

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