Winch for black=out screens or blinds - has ball type chain and expanding split sleeve acting as brake on cylinder

摘要

The winch for blackout screens or blinds has a canvass or similar sheet (2) fixed to a rotating drum (3), the ball chain (9) rotating the cylinder (4) by gripping studs (4c). The cylinder rotates freely about the split sleeve (6b) when the truncated socket (7) fits loosely into the sleeve. Turning the bolt (8) from outside the end plate (6) of the assembly (1) against the nut (8a) forces the truncated socket into the sleeve, expanding the latter until it acts as a brake to the rotating cylinder and hence the rotating drum and screen.