Locking piece definitions

Locking piece

1) Sculpture by Henry Moore
Found on https://www.crosswordclues.com/clue/locking-piece

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locking piece

(in a striking train) a hooked part, rising and falling on a locking plate and arresting the rotation of the plate after the proper number of strokes.
Found on https://www.infoplease.com/dictionary/locking-piece

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