| 摘要 |
PURPOSE:To shorten the production process, to reduce the cost and to improve the dimension precision, by forming a cam groove in such direction that the center line of the cam groove in the breadthwise direction is always orthogonal to a prescribed plane including the optical axis. CONSTITUTION:A cam groove 2 is formed on a cam cylinder 1 in such direction that the center line of the cam groove 2 in the breadthwise direction is orthogonal to a horizontal plane X-X including an optical axis O-O', and a cam groove detaining part of a cam pin 5 to be engaged with the cam groove 2 is formed to a shape like a ball. As a result, a mold is slided from the outside-diemeter side of a cam cylinder 5 to form the cam groove 2, and the cam cylinder 5 and the cam groove 2 are produced by the molding work of a synthetic resin or the press work of metallic materials. Consequently, the production process is shortened, and the cost is reduced, and the dimension precision is improved. |
