Cassette for a printing ribbon for typewriters.

摘要

A cassette (11) for a printing ribbon (33) for typewriters comprises a casing (12) accommodating a supply spool (34), a receiving spool (36) and a brake and take up device (39) which operates on a tube (37) of the supply spool (34) and on the ribbon (33) which is unwound from the supply spool (34). The tube (37) is rotatable on a sleeve (38) projecting from the bottom (13) of the casing (12) . The brake and take up device (39) comprises a shoe (47) for applying a braking action to an internal surface (41) of the tube (37). A wire spring (48) has an intermediate portion (52) which engages in a seat (56) of coupling means (46) of the shoe (42). In a first position the shoe (42) is urged against the surface (41) of the tube (37) and brakes the supply spool (34). In a second position the shoe (42) is spaced from the internal surface (41) of the tube (37) and the supply spool (34) is free to rotate. The spring (48) also performs the slack ribbon take-up function and for that purpose comprises an end (54) having an L-shaped bent portion (55) which in turn is engaged with the ribbon (33) to regulate the tension and unwinding of the ribbon (33) which is unwound from the supply spool (34).