| 摘要 |
A flashlight comprises a battery housing component and a lamp housing component, both with peripheral walls of elliptical cylindrical shape having, respectively, the same major and minor diameters, and terminating at one end, respectively, in a circular edge that lies in a plane that is oblique to the axis of the cylindrical wall by a selected angle A and includes a major diametrical chord of the ellipse of the walls. The minor diameter of the ellipse of the peripheral walls of each component is equal to the cosine of the angle A times the major diameter. The housing components are joined together with their circular edges meeting for rotation of the lamp housing component on the battery housing component, thereby permitting adjustment of the direction of the light beam relative to the axis of the battery housing component. |
