| 摘要 |
PURPOSE:To reduce load unevenness and friction, to reduce the clearance between a bearing and a groove, and to prevent an image flicker and an out- of-focus image by pressing the bearing against a groove surface by a member such as a spring. CONSTITUTION:One groove is provided with two bearings 2a and 2b coaxially with a bearing shaft 6, and the spring and another elastic member 8b, etc., are provided to the bearing shaft 6 so that one bearing 2b is prssed against the groove surface 3b. Consequently, only one surface of the bearing 2b contacts the groove surface 3b, so loading uneveness and frictional resistance in operation decrease and the clearance between the bearing 2b and groove surface 3b is held small. This groove cam mechanism is applied to the zooming mechanism of a zoom lens to prevent an image flicker and an out-of-focus image. |
