GB690502A - Improvements in lanterns for street lighting purposes - Google Patents

Abstract

690,502. Street lighting fittings. HOLOPHANE, Ltd., and ENGLISH, S. June 28. 1951 [July 22, 1950]. No. 18360/50. Classes 75(ii) and 75(iv) In a lantern for street lighting providing two downwardly inclined beams in substantially opposite directions part of the light directing means is in the form of a figure of revolution and is adjustable relative to the lantern about an axis normal to the plane of the beams so that as one beam is elevated the other is depressed to suit street gradients, whilst leaving the general appearance of the lantern unaltered. In the fitting shown the light directing means comprise a refractor having longitudinal prisms and formed by two conical frusta, 1, 2 held with the larger end 6 of one in abutment with a socketed flange 5 on the larger end of the other by three rods 15 which extend through the frusta and are secured by nuts 16 to metal rings 9, 10 fitted against the smaller flanged ends of the frusta. The ends of the rods pass through arcuate slots 18 in castings 13, 14 supported from an arm 27 and are secured to the castings by nuts 19, the slots permitting rotational adjustment of the refractor. One of two lugs 21 on the refractor coact with a graduated plate 22 on the casting 13 to provide an indication of the tilt of the main beams. The casting 14 is hollow and carries a holder 24 for an elongated lamp 25 which is disposed along the axis of the refractor. Removable end caps 28, 29 are provided on the castings. In a modification the metal rings are omitted and the small ends of the frusta seat in recesses in the castings and the lugs 21 fit in arcuate slots in the castings. The two frusta may be replaced by a single cylinder. In a further modification the refractor is of tapering form closed at its smaller end. Its open larger end has an outwardly directed lip which is retained with freedom to rotate in an annular recess in a metal ring by a washer secured to the ring. by screws. A lug on the lip coacts with a slot in the metal ring to limit the rotation of the refractor. The metal ring is secured to a casting having a socket for a supporting arm and carrying a lampholder. A curved reflector is supported from the casting inside the refractor.