Device for rapidly mounting/releasing units for fitting caps or lids to containers, in particular for mandrels of automatic machines

A capping assembly comprising:

• at least one mandrel rotatable about a respective axis in one direction;
• a tube mounted on at least one mandrel and rotatable therewith about said axis and formed with an outer end;
• a bell-piece mounted fixed on the tube and coaxial therewith and spaced axially from the outer end of the tube;
• a bush mounted axially displaceable between inner and outer axial positions thereof on the outer end of the tube and rotatable about said axis in the inner position, the bush being formed with an eyelet means extending axially inwardly toward the bell-piece to form an annular chamber;
• resilient means in said chamber braced against the bush for thrusting the latter into said inner position thereof;
• pneumatic means in flow communication with said chamber for controllably counteracting said resilient means to axially displace said bush toward said outer position;
• a cap holder received in said bush and formed with engaging means extending radially outwardly for releasably engaging the cap holder and said eyelet means in said inner position of the bush to rotate therewith.