Retention by pivotal elements, e.g. catches, pawls

Full Title

Chucks ; Expansion mandrels; Adaptations thereof for remote control (faceplates B23Q1/50; rotary devices holding by magnetic and/or electrical force acting directly on work B23Q3/152) > Chucks > characterised by the retaining or gripping devices or their immediate operating means > Retention by pivotal elements, e.g. catches, pawls