Patent ID: 6826893
Filing Date: 2004-12-07
Classification: B65B

Abstract:
An apparatus (1) for wrapping a group of products with plastic film (50), the apparatus comprising:a frame (2) that mounts a ring-shaped element (3) supporting a carriage (4) that moves around the ring-shaped element (3); drive means (5) for moving the ring-shaped element (3) relative to the group (P) of products to be wrapped along a wrapping axis; main motor means (6) for driving the carriage (4) around the group (P) of products; the carriage (4) adapted to mount a roll (7) of plastic film (50) and further comprising a pre-stretching unit (8) driven by drive means (9) for the pre-stretching unit; the pre-stretching unit (8) comprising a pair of film pre-stretching rollers (10), and at least one transmission and control roller (12) that swings towards and away from an associated group (P) of products to be wrapped, said transmission and control roller adapted to start or stop film feed, through the pre-stretching unit drive means (9), according to its position relative to the associated group (P) of products to be wrapped, wherein the pre-stretching unit drive means (9) comprise a kinematic chain comprising: the main motor means (6) for rotating the carriage (4); a ring-shaped, continuous drive take-off track (13) for the pre-stretching unit drive means (9) which comprise an engage/release unit (14) connected to and controlled by the transmission roller (12) and designed to transmit drive from the ring-shaped track (13) to the pair of pre-stretching rollers (10) according to the position of the transmission roller (12) relative to the associated group (P) of products to be wrapped.