Clutch for ejector mechanism in injection moulding tool - has auxiliary piston within operating piston to keep clutch locked even if actuating fluid pressure drops

摘要

Clutch (16), has radial clutch fingers (36) which are moved by annular piston (27) driven by pressurised fluid. Second annular piston (53) slides axially within the main piston (27) between stops (56) to control shut-off device (46). The shut-off device (46) is moved from its locking recess (48) by fluid pressure. The shut-off device can be a ball valve (46) resting within safety recess (58) in the second piston (53) as well as in the locking recess (48). The same pressure fluid can be used for both pistons (27, 53). USE/ADVANTAGE - The invention ensures that the clutch remains locked even during accidental actuating fluid pressure loss.