Patent ID: 7356976

Claim:
An apparatus for automatic change of the reel of extensible film in wrapping machines for packaging palletized loads, with the pallet stationary or the pallet rotating, said apparatus comprising: a fixed or rotating supporting structure for wrapping the film around a pallet, provided with an assembly for carrying a reel of the wrapping film and with means for retention of the free end of the film of a reel; the fixed or rotating structure, constrained to the sliding frame, being mobile vertically for moving said assembly between a raised wrapping position and a lowered position for changing reel that has run out or is defective; a service carriage for carrying a new reel, provided with means of temporary support of the free end of the film of the new reel, which is configured to co-operate with said retention means; the carriage being mobile between two end positions respectively of parking and of changing the reel that has run out or is defective; means of release and of expulsion of the reel that has run out or is defective from the fixed or rotating supporting structure; means for positioning the carriage for carrying a new reel into a position corresponding to the assembly that carries the reel that has run out or is defective; means for causing the assembly of the wrapping reel to perform said vertical translation up to said position of reel change, in which it is in a position corresponding to the carriage for carrying a new reel in order to cause the respective spindles for carrying a reel to co-operate with the respective means for temporary support and retention of the end of the film; means for picking up the new reel from the carriage on which it is located and for constraint with the assembly carried by the wrapping ring; means for transfer of the free end of the film of the new reel from said means of temporary support to said retention means; means for bringing back the fixed or rotating supporting structure into the wrapping position; and means for moving the carriage away to bring a new reel from the position of reel change; wherein the carriage for carrying a new reel slides on a conveyor equipped with two linear guides, actuated by pneumatic cylinders, and wherein the pneumatic cylinders are two combined cylinders, of which one cylinder, which is fixed to the carriage, carries the carriage into a position of expulsion of the reel that has run out or is defective, and wherein the other cylinder, which is fixed to the conveyor, sets the carriage in a position for picking up the new reel.