Device and method for shrinking a shrink film onto a stack of goods

Abstract

The invention relates to a device for shrinking a shrink film ( 1 ) onto a stack of goods ( 2 ), wherein a shrink frame ( 3 ) is provided, which can be moved on the stack of goods and which surrounds the stack of goods while the shrink film is shrunk on. The shrink frame has a plurality of heating apparatuses distributed over the perimeter of the shrink frame for heating the shrink film for the shrinking process. Furthermore, there is a cover plate ( 6 ) that covers the stack of goods and that is arranged in particular at a distance from the top side ( 7 ) of the stack of goods during the shrinking process. Side walls ( 11 ) extending along the stack of goods are provided between the shrink frame and the cover plate, and intermediate spaces for the heated gases flowing upward are formed between the stack of goods and the side walls. The cover plate can be moved toward the top side of the stack of goods and can be moved away from the top side of the stack of goods. The side walls form a frame, in particular a rigid frame, and the cover plate can be moved within said frame.

1 . An apparatus for shrink-fitting a film onto a stack of objects with a shrink frame that can be moved over the stack of objects and that surrounds the stack of objects during the shrink fitting, the apparatus comprising:
 a shrink frame with a plurality of heaters distributed around its periphery for heating the film for the shrinking process and causing gases to flow up around side faces of the stack,   a cover plate covering the stack of objects and spaced from the top face of the stack of objects during the shrinking process, and   side walls extending along the stack of objects below the cover plate, below the cover plate, and forming clearances between the stack of objects and the side walls for heated gases flowing upward, the cover plate being movable toward the top face of the stack of objects and away from the top face of the stack of objects, the side walls forming a rigid frame within which the cover plate can move.   
     
     
         2 . The apparatus according to  claim 1 , wherein the rigid frame can be suspended from the cover plate, and in a suspended state, the frame can move with the cover plate. 
     
     
         3 . The apparatus according to  claim 1 , wherein the frame has upper cover segments to form a box, and in a suspended state of the frame or box from the cover plate, the cover segments rest on the cover plate. 
     
     
         4 . The apparatus according to  claim 1 , wherein the frame is formed by a first partial frame or box, and a second partial frame or box, the first partial box engaging with or being engageable with the second partial box, the cover plate being moveable in the first partial box or in the second partial box for adjusting a space between the stack of objects and the cover plate. 
     
     
         5 . An apparatus for shrink-fitting a film onto a stack of objects, the apparatus comprising:
 a shrink frame that can be moved over the stack of objects and that surrounds the stack of objects during the shrink fitting,   the shrink frame with a plurality of heaters distributed around its periphery for heating the film for the shrinking process and causing gases to flow up around side faces of the stack,   a cover plate covering the stack of objects and spaced from a top face of the stack of objects during the shrinking process, and   below the cover plate, side walls extending along the stack of objects and forming between the stack of objects and the side walls, clearances for the heated gases flowing upward, the side walls being made of a flexible material so that during downward movement of the shrink frame, the flexible side walls can be rolled off winders on the cover plate in accordance with the downward movement of the shrink frame.   
     
     
         6 . The apparatus according to  claim 5 , wherein the inner shell formed of the side walls and the cover plate is enclosed by an outer shell having an upper outer plate and outer side walls such that the heated gases escaping from the cover plate can flow in the clearances formed between inner shell and outer shell to the shrink frame, or, vertically downward to the shrink frame. 
     
     
         7 . The apparatus for shrink-fitting a film onto a stack of objects as defined in  claim 1 , the apparatus comprising
 a shrink frame that can be moved over the stack of objects and that surrounds the stack of objects during the shrink fitting, the shrink frame being provided with a plurality of heaters distributed around its periphery for heating the film for the shrinking process and causing gases to flow up around side faces of the stack,   a cover plate covering the stack of objects, spaced from a top face of the stack of objects during the shrinking process,   below the cover plate, side walls are provided extending along the stack of objects, and wherein between the stack of objects and the side walls, clearances for the heated gases flowing upward are formed, and   an outer shell enclosing an inner shell formed of the side walls and the cover plate and having an upper outer plate and outer side walls such that the heated gases escaping from the cover plate can flow in the clearances formed between the inner shell and the outer shell to the shrink frame or, vertically downward to the shrink frame.   
     
     
         8 . The apparatus according to  claim 7 , wherein the side walls of the inner shell or the outer side walls of the outer shell are configured in a bellows-like manner. 
     
     
         9 . The apparatus according to  claim 7 , wherein the side walls of the inner shell or the outer side walls of the outer shell can be rolled onto winders, or can be rolled off the winders. 
     
     
         10 . The apparatus according to  claim 5 , wherein the cover plate can be moved to the top face of the stack of objects and can be moved away from the top face of the stack of objects. 
     
     
         11 . The apparatus according to  claim 1 , wherein the side walls or the lower ends of the side walls are fixed to the shrink frame. 
     
     
         12 . The apparatus according to  claim 1 , wherein the cover plate covering the stack of objects is provided with at least one outlet port for extracting heated gases generated during the shrinking process, the apparatus further comprising:
 at least one blower that can extract heated gases by suction, or with which cool gases or cool air can be fed in.   
     
     
         13 . The apparatus according to  claim 1 , wherein the cover plate can be displaced or moved independently of the displaceability of the shrink frame. 
     
     
         14 . In a method for shrink-fitting a film onto a stack of objects wherein the film is shrink-fitted onto the stack of objects with a shrink frame and for this purpose the shrink frame surrounding the stack of objects can be moved over the stack of objects, the film thereby being heated for shrink-fitting by a plurality of heaters distributed around the periphery of the shrink frame, the improvement comprising the steps of:
 moving a cover plate above the stack of objects toward the stack of objects or away from the stack of objects for adjusting a space between the cover plate and stack of objects,   flowing heated gases generated during the shrinking process through clearances formed between the stack of objects and side walls connected to the shrink frame,   removing the heated gases are by suction through at least one outlet port provided in the cover plate, and   during the displacement toward the stack of objects and during the displacement in the opposite direction, moving the cover plate in a rigid frame formed of rigid side walls.   
     
     
         15 . The method for shrink-fitting a film onto a stack of objects defined in  claim 14 , the method comprising the steps of:
 shrink-fitting the film onto the stack of objects with a shrink frame surrounding the stack of objects by moving the shrink frame over the stack of objects such that the film is heated for shrink-fitting by way of a plurality of heaters distributed around the periphery of the shrink frame,   moving a cover plate above the stack of objects toward the stack of objects or away from the stack of objects for adjusting a height of a space between the cover plate and stack of objects,   flowing heated gases generated during the shrinking process through clearances that are formed between the stack of objects and side walls connected to the shrink frame,   removing the heated gases by suction through at least one outlet port provided in the cover plate, and   during displacement of the cover plate toward the stack of objects, rolling up the side walls as flexible side walls onto a winder, and during the displacement of the cover plate in the opposite direction rolling the flexible side walls off the winder again.   
     
     
         16 . In the method defined in  claim 14  for shrink-fitting a film onto a stack of objects where the film is shrink-fitted onto the stack of objects with a shrink frame surrounding the stack of objects and movable over the stack of objects such the film is heated for shrink-fitting by a plurality of heaters distributed around the periphery of the shrink frame, the improvement comprising the steps of:
 moving a cover plate above the stack of objects toward the stack of objects or away from the stack of objects for adjusting a height of a space between the cover plate and stack of objects, 
 flowing heated gases generated during the shrinking process through clearances formed between the stack of objects and side walls connected to the shrink frame, 
 removing the heated gases by suction through at least one outlet port provided in the cover plate, and 
 enclosing the inner shell formed of the side walls and the cover plate by an outer shell having an upper outer plate and outer side walls such that the heated gases escaping from the cover plate can flow in the clearances formed between the inner shell and the outer shell to the shrink frame, or, vertically downward to the shrink frame. 
 
     
     
         17 . The method according to  claim 14 , further comprising the step of:
 initially moving the shrink frame at least to the bottom side of the stack of objects and   subsequently, during operation of the heaters for heating and for shrink-fitting the film, moving the shrink frame toward the top face of the stack of objects.   
     
     
         18 . The method according to  claim 17 , further comprising the step of:
 operating the heaters also during the displacement of the shrink frame to the bottom side of the stack of objects for heating the film.   
     
     
         19 . The method according to  claim 14 , wherein further comprising the step of:
 reducing a heat output of the heaters if the film is heated by the heated gases flowing to the cover plate.   
     
     
         20 . The method according to  claim 14 , wherein the heated gases are removed by suction through the at least one outlet port in the cover plate with the aid of at least one blower.