Coupler of winding key with power spring

摘要

A coupler of winding key with a winding shaft comprises a threaded member formed on one of the key and the shaft and a bottomed aperture formed in the other in which a coiled spring is locked against withdrawal. The threaded member is threadably engaged with the coiled spring to couple the key with the winding shaft. When the winding key is turned in a direction to spread the coiled spring, a rotating drive is transmitted to the winding shaft while the key rotates idly when it is turned in a direction to tighten the coiled spring.