Device and method for automatic changing of film rolls

A method for automatically changing film rolls, comprising:

• locating a first film roll in a working position wherein said film roll is rotatable for pulling off and separating film from said film roll;
• locating a second film roll in a standby position;
• measuring film pulled from said first roll in the working position, and generating a corresponding signal at a predetermined state of film removal;
• when a corresponding signal is generated, moving said second film roll from the standby position to the working position;
• moving an ejecting device in tandem with second film roll, movement of said ejecting device with said second film roll displacing said first film roll from said working position before said second film roll reaches the working position;
• and
• when the corresponding signal is generated, rewinding onto the first film roll film that has already been pulled off the first film roll and not yet separated, before or during movement of second film roll.

A device for the automatic changing of film rolls, comprising:

• a working position in which a first film roll is rotatably mounted centered between two movable receiving cones positioned axially opposite each other, with a free film end of the film being held in a defined position against a suction strip, so that the film is removable and separatable from the first film roll, wherein the receiving cones situated in the working position are movable axially against the film roll and, movable away from it removing the film roll from the working position;
• a waiting position arranged below the working position, in which a second film roll is supported in a ready position on rotating support cylinders, with a free end of the second film roll attached to a positioning rod, said rotating support cylinders with the second film roll and the positioning rod being mounted on a pallet that is vertically movable by a lifting mechanism from the waiting position into the working position and movable back into the waiting position;
• a swinging ejection strap mounted on the pallet and able to be lifted and lowered for ejecting the first film roll, by means of which, during lifting movement of the second film roll, the first film roll released by the receiving cones is vertically movable out of the working position for dropping into a core receptacle also situated on the pallet;
• wherein the beginning of the film of the second film roll, attached to the positioning rod, is deliverable to the suction strip in the working position after lifting of the second film roll into the working position and the coil core of the second film roll can be taken over by the receiving cones.

A process for automatic dispensing and changing of film rolls, comprising:

• receiving a first film roll in a working position centered between receiving cones that are movable in controlled manner and situated axially opposite each other;
• holding a free film end of the first film roll in a defined position against a suction strip;
• pulling off and separating film from the first film roll;
• providing a second film roll, resting on rotating support cylinders, in a waiting position situated below the working position;
• and
• attaching a free film end of the second film roll to a positioning rod on a vertically movable pallet;
• lifting the pallet with the second film roll into the working position while simultaneously releasing the centering of the first film roll;
• dropping the first film roll via a swinging ejection strap into a receptacle situated on the pallet;
• delivering the end of the second film roll from the positioning rod of the palette to the suction strip of the working position;
• and
• the receiving cones taking over a coil core of the second film roll after the second film roll is lifted into the working position.