| 摘要 |
<p>PURPOSE:To prevent breakage of a leaf spring by providing concave portions where both ends of a roller are fitted with a space in the radial direction of the roller on both retainers, whereby when the roller moves to the unlock side end portion, the leaf spring is not totalling compressed. CONSTITUTION:Shallow concave portions 15 where both end portions of a roller 14 longer than a conventional roller are fitted with a gap G in the radial direction of the roller are disposed at equal intervals corresponding to the number of the rollers 14 on flat surfaces 8 with which retainers 11 on both sides confront. The concave portion 15 is a circular hole having a radius larger than that of the roller 14 by the above gap G, so that the roller 14 can move from the position concentric with the concave portion 15 in the opposite direction to the direction of an arrow A by the gap G. Even if the roller 14 is moved toward the unlock wide (in the opposite direction to the arrow A) to reach the position 14', the roller compresses the leaf spring by the gap G which is far from the total compression.</p> |
