GB316281A - Improvements in and relating to miners' electric lamps - Google Patents

Abstract

316,281. Daloz, J. G. July 27, 1928, [Convention date]. Battery lamps.-In miners' lamps of the kind wherein the electric circuit is maintained by pressure of fluid within the bell a, the bulb g is mounted in an elastic membrane f that closes the mouth of the bell, and is formed so that when it is first applied to the bell it protrudes outwardly as shown in Fig. 5, and when pushed inwards to the position shown in Fig. 1 compresses the fluid within the bell, thus dispensing with the usual inflating-apparatus. The edge of the membrane may be sprung around the flange of the bell as shown in Fig. 1, and clamped between the lamp top e' and the usual contact plate h, or it may applied to the flange as shown in Fig. 5 and clamped thereon by a separate ring. If the lamp be damaged and the fluid escape from the bell, the lamp circuit is broken by a spring k forcing the bulb g away from a contact j, Fig. 1, or by forcing the tubular contact j, Fig. 3, out of a conducting socket j<2>, or by forcing a pin j, Fig. 5, which is carried by the bulb-holder, out of a socket in the contact plate. To prevent the miner from remaking the electric circuit when the bell is broken, a loose metal ball n, Fig. 1, may normally be gripped between the contact and the bulb contact so that it falls away when the membrane is distended to break the circuit, or a slip m, Fig. 2, of insulating material may be drawn between the bulb and the contact by a spring m<1>, or resilient tongues j<0>, Fig. 3, at the end of the contact tube may prevent its re-insertion in the socket j<2>, or the end of the pin j, Fig. 5, may be non-circular to prevent its re-insertion in its socket, or this may be prevented by a spring- operated insulating strip. Chloroform or other volatile liquid may be placed in the bell to replace by evaporation gas lost by leakage, and a scale may be arranged in the lamp or on the bell to give a visible indication of any slow movement of the membrane caused by leakage of the gas.