Importance

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Abstract

A fastener apparatus for joining together a plurality of plates, including an internally-threaded pin adapted to be guided through aligned openings in the plates and a generally cup-shaped accommodating element that can be tightened with the pin via a threaded bolt mounted centrally therein. The accommodating element carries one or more springs for yieldably resisting entry of the pin and further carries two locking washers accommodated on the threaded bolt, for preventing an unintended loosening of the pin out of its tightened position. The locking washer that faces the pin is rotatably guided and axially displacable up to an external stop of the accommodating element, and the locking washer that faces away from the pin is rotation-fast but guided in displacable fashion within the accommodating element, axially against yielding bias of the spring. When a torque is applied by the pin that exceeds a certain value, the two locking washers are rotatable relative to each other, such that the pin can be threaded onto the bolt. In addition, the locking washers are configured to have frusto-conical surfaces that compressively engage each other, the surfaces providing an adhering friction when the pin is fully threaded onto the bolt, and a lesser, sliding friction when one surface is rotating relative to the other.

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First Claim