PURPOSE:To improve spring fatigue strength and to prevent local abrasion of a sprag and a tab by forming E-shaped sprag insertion holes by designated pitches on an elongated metallic thin plate and forming a pair of tabs spaced from each other on one side portion. CONSTITUTION:Substantially E-shaped sprag insertion holes 7a are punched by designated pitches along the longitudinal axis of an elongated thin plate made of stainless or the like, and a pair of side portions 7b and a bridge portion 7c bridging therebetween are formed. Further a pair of tabs 7d' spaced from each other are projected on one side portion of the bridge portion 7c into the sprag insertion hole 7a. Accordingly the oscillation and skew of the sprag in the insertion hole 7a can be prevented, the fatigue strength of a spring can be improved and the local abrasion of the sprag and the tab can be prevented.
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