| 摘要 |
<p>401,972. Lenses for vehicle lamps. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Roper, V. J. ; 1849, Lampson Road, Cleveland, Ohio, U.S.A.) April 28, 1933, No. 12454. Convention date, April 29, 1932. [Class 75 (ii).] A lens for a vehicle lamp comprises a middle zone 36 formed with vertical flutes 37 giving a narrow spread horizontally, side zones 30, 31 formed with vertical flutes 32, 33 giving a medium spread horizontally and with vertical prisms 34, 35 which refract the light horizontally to the right and left respectively, and top and bottom zones 24, 25 formed with vertical flutes 26, 27 giving a wide spread horizontally and with horizontal prisms 28, 29 refracting the light downwardly. The second face 38 of the middle zone 36 may be plane or formed as a slightly downwardly refracting prism, and the lens may also be provided with a central zone 39 formed with vertical flutes 40 giving a wide spread horizontally and with horizontal prisms 41 refracting the light downwardly. The flutes may be formed on one face of the lens and the prisms on the other face, or the flutes and prisms may both be formed on one of the faces, and the surfaces of the prisms may be slightly curved. This lens is used in combination with a paraboloidal reflector and an electric lamp bulb having three filaments which may be switched on selectively to obtain substantially symmetrical beams for driving on the open road, asymmetrical non-glaring beams for use when passing other vehicles, and downwardly directed beams for use in towns, as described in Specification 401,891.</p> |
