| 摘要 |
373,399. Refractors for street lamps. REVO ELECTRIC CO., Ltd., REEVES, F. H., Britannia, Works, Groveland Road, Tividale, Tipton, Staffordshire, HOLOPHANE, Ltd. and ENGLISH, S., Holophane House, Elverton Street, Vincent Square, London. May 15, 1931, No. 14357. [Class 75 (ii).] A one-piece dome-shaped directional refractor for street lamps of circular or elliptical horizontal section has an upper zone of horizontal refracting prisms a, b both internally and externally, and one or more dioptric lenses c comprising a succession of concentric semicircular or semielliptical refracting prisms. The external horizontal prisms b are continued downwardly over the dome at b<1>, the zone of these prisms merging into the lenses. The interior of the dome is provided with vertical prisms d except where the lenses occur. |
