| 摘要 |
PURPOSE:To prevent overload from being transmitted to a system between a draw string and a spring and to prevent breakage of the system by engaging a lock member mounted at a connecting portion of a pulley to the draw string with a fixed engagement wall to regulate the movement of the draw string at the time of overload produced by winding up the spring. CONSTITUTION:When a draw string 26y is drawn, and load produced by completion of winding up a spring exceeds elastic force of an urging spring 28, the draw string 26 causes a lock lever 24 to pivotally displace around a shaft 25. As a locking engaging portion 38 of an engagement wall 37 is positioned in the area of displacement of the lock lever 24, the lever 24 has a finger portion 24d engaged with the engaging portion 38. The string 26 will not be drawn due to this engagement, so that the tensile force of the draw string 26 is received through the lock lever 24 by the engagement wall 37 which is an immobile member to be dispersed to a case. Thus, the overload produced by the draw string 26 is not transmitted to a system between the draw string 26 and the spring to prevent breakage of the system. |
