| 摘要 |
762,769. Street lighting refractors. METROPOLITAN - VICKERS ELECTRICAL CO., Ltd. Oct. 20, 1954 [Oct. 16, 1953], No. 28631/53. Classes 75(2) and 75(4) A street lighting refractor 'provided on a surface with a plurality of prisms has the prisms 6<SP>11</SP> over at least a portion of the total arc covered by the refractor, particularly those receiving upwardly directed light which are' required both to reflect and refract the light downwardly spaced at their bases to an extent such as to avoid interception by one prism of the path of light emanating, in use, from the source and passing through an adjacent prism. Relatively small prisms 7 are provided between the main prisms 6" to reflect back towards the interior of the lantern light, e.g. upwardly directed, which would otherwise pass through the refractor between the main prisms and in the case where the prisms are on the side of the refractor away from the light source, the prisms 7 may be double reflecting right-angled prisms. The refractor may in the form of a bowl or trough-shaped portion for a lantern body or of a skirt portion for an open type lantern body and may be of glass or " Perspex " (Registered Trade Mark) or particularly, moulded from " Diakon " (Registered Trade Mark). The refractor described forms the skirt of a globe and is provided at its upper end with an inturned flange for securing by screws to bosses on a cap or canopy, e.g. of aluminium. |
