| 摘要 |
446,096. Lamps for illuminating long areas. FISHER, H. J., Moor View, Harrogate Road, Ripon. Oct. 23, 1934, No. 30315. [Classes 75 (ii) and 75 (iv)] An electric lamp, suitable for illuminating a relatively long area such as a corridor or a mine roadway, is provided with a well glass f formed internally with pairs of oppositely disposed sections having circumferential and straight prisms g, h adapted respectively to provide short and long beams. The glass f is made of tough heat-resisting clear glass with a plain smooth outer surface and the lamp is so mounted that the straight prisms are parallel to the length of the area to be illuminated. A wire guard is so arranged that its intersecting members coincide with the divisions between the four sections of the glass f. The latter is cemented into a holder m which is secured by stud-bolts p, p<1>to an inclined flange n on a gas-tight casing a. The inner end of the studbolt p<1> engages the lower end of a rod q which is slidably mounted in a vertical hole at one side of the casing a and has a pin s projecting through a slot t into the interior of the casing. The pin s carries an insulating block u to which is attached a spring v anchored to a part z of the casing a. The block u carries a U-shaped metallic contact w which engages between stationary contacts x carried by an insulating strip y. The parts w, x form an interlocking switch by means of which the current supply to the bulb d is automatically cut off when the stud-bolt p<1> is withdrawn to remove the glass f and its holder m from the casing a. The switch may be connected in the supply circuit to the lamp holder c or in a pilot circuit which cuts off current to the bulb d. Alternatively, the pilot interlock may be effected by the engagement of plug-and-socket couplings. |
