| 摘要 |
<p>A housing (20) is fixed on an adjustable member (18) and supports the same for sliding movement on a portion of a support member (15). Notches (44) are spaced vertically along the upper portion of the support member and a pawl (32) is pivotally supported on the housing and includes a ratchet finger (35) movable between an operative position with the ratchet finger in engagement with the notches and an inoperative position with the ratchet finger out of engagement with the notches. A spring (40) is associated with the pawl and is operable to selectively maintain the ratchet finger in either the operative or inoperative positions. When the adjustable member is moved in a first direction to one end of its adjustment limit, the pawl is switched to the inoperative position and the adjustable member may be freely moved to the other end of the adjustment limit in preparation for a subsequent adjustment in the first direction.</p> |
