| 摘要 |
PURPOSE:To guarantee stable tracking control by always stabilizing a reel base plate against a variation of temperature and setting it in a state which is not influenced by a distortion stress, even in case when materials whose coefficients of thermal expansion is combine used. CONSTITUTION:On a reel base plate 24 are formed hooks 42a, 42b which turn to one direction corresponding to the diameter line X, and also a hooking hole 43 is formed corresponding to the line X. The said hole 43 is constituted of a large diameter part 43a, and a hooking part 43b which is formed continuously to said part and extended in the direction of the hooks 42a, 42b, and a hooking substance 44 is formed on a bottom plate 28a of a case body 28, corresponding to said hole 43. That is to say, the reel base plate 24 is set to the bottom plate part of a case body 28 so as to insert the hooking projecting body 44 into a large diameter part 43a of said hole 43, and when this reel base plate 24 is rotated in the direction as indicated with an arrow 45, hooking parts 39a-39d are inserted into stop grooves 41a-41d, and the reel base plate 24 is set in a state that it is controlled in the direction of height. |
