Patent GB-347811-A (GB)
Title: Improvements in or relating to electric lamps for use in mines and other places
IPC: F21V33/00
Filed: 1930-03-07
Abstract: 347,811. Miners' lamps. OLDHAM & SON, Ltd. and DARBY, G. H., 36, Hyde Road, Denton, near Manchester. March 7, 1930, No. 7553. [Classes 39 (ii) and 75 (iv).] Electric battery lamps; convertible electric, oil, and like lamps.-An electric battery lamp adapted particularly for use in mines comprises a lamp and battery casing 1, Figs. 1 and 2, provided with a lid or cover 2, and a casing 28 associated therewith and containing gas-detecting means comprising a liquid-fuel container 36 provided with a wick 35, and a filament 34 for igniting the wick, exteriorly controlled switching-devices being connected to contact members which are arranged in the lamp and filament circuits and are connected to the battery when the cover of the battery casing is closed. The accumulator is provided with terminals 6, 8 which are preferably yieldable and, when the hinged cover 2 is closed, respectively engage contact members 5, 21 on the cover, the contact 5 being in the form of a metal bush connected to an insulated metal strip 9 which extends laterally in both directions and is provided at its end with resilient contacts 13, 23. The contact 13 extends through an insulating block 14 in the cover and is adapted, when the cover is closed, to engage a terminal 14 connected by a conductor 15<1> to one of the terminals 16 of a switch 17 of the screwoperated type, the other terminal 16 being connected to a flexible strip 19 against which the centre contact of the lamp bears. Current returns to the negative terminal 8 of the accumulator by way of the lamp casing and the contact 21 on the cover. A padlock or other means is provided to secure the lid in its closed position. The oil or like fuel burner for detecting the presence of gas or firedamp is preferably detachably mounted in the casing 28, for example by screwing its reservoir 36 in position, and when the cover is closed the circuit of the wickigniting filament 34, together with that of an electric inspection bulb 27 arranged within the casing 28, are connected by a lead 25 to the contact 23 carried by the lid. Separate switches for the lamp 27 and filament 34 respectively are provided by resilient blade springs 30, 37 controlled by externally operated heads or plungers. The gauzes 44 of the detecting device are mounted upon a shield-ring 47 which is screwed into the casing 28, and the lens 29 is also retained in position by a ring 50 screwed into the front of the casing. Interlocking devices for preventing the removal of the lamp reservoir 36, gauze shield 48, and ring 50 until the cover 2 is opened and the battery circuit broken respectively comprise, a vertical rod 39 which is pushed by the cover into an aperture 40 in a lug on the reservoir ; a vertical rod 57, Fig. 4 (not shown), which normally rests upon the reservoir and is held so that its upper end engages within an aperture in the ring 47 until the reservoir is rotated to allow the rod to drop ; and a detent 52 which is pivoted on the casing and normally engages within a recess 51 in the lens ring 50, a rearward extension 54 on the lug being engaged by the ring 47 to prevent a disengaging movement of the lug until the ring 47 is released.