Process and apparatus for increasing stacking strength of film wrapped articles

The objective of the invention is to provide an alternative way of wrapping a product with cardboard at faster speed and maintain stacking strength. This accomplished by bending two strips of cardboard into the shape of a U channel where the sides of the U form an angle smaller than 90 degrees with the center part of the U form. The sides of the U channel cardboard will be open by a guide that will allow each U channel cardboard piece to slide around each end of the product without requiring glue to hold the U Channel in position. By maintaining an angle of less than 90 degrees the U channel cardboard acts like a spring clamp around the product and maintains its position on the conveyor belt while the product is film wrapped and the film is heat shrunk.

FIELD OF INVENTION

This invention relates to providing packing strength to products that have been wrapped with heat shrink film. The product can be a single item or a bundle of items.

BACKGROUND OF THE INVENTION

A material, such as a corrugated cardboard, has been used to wrap a product to provide stacking strength. The single piece of cardboard when wrapped around the product requires using glue to hold the cardboard around the product. The single piece is very long and difficult to bend or prebend during the wrapping of the product. To accommodate the wrapping of the product with the single piece of cardboard requires that the film wrapping machine slows down from its normal speed.

SUMMARY OF THE INVENTION

The objective of the invention is to provide an alternative way of wrapping a product with cardboard at faster speed and maintain stacking strength. This accomplished by bending two strips of cardboard into the shape of a U channel where the sides of the U form an angle smaller than 90 degrees with the center part of the U form. The sides of the U channel cardboard will be open by guides that will allow each U channel cardboard piece to slide around each end of the product without requiring glue to hold the U Channel in position. By maintaining an angle of less than 90 degrees the U channel cardboard acts like a spring clamp around the product and maintains its position on the conveyor belt while the product is film wrapped and the film is heat shrunk.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a product1moving on a conveyor2. The product1can be a bundle of articles or a single article. On each side of the product1, two corrugated cardboard pieces3and4located on the side of the conveyor. The card board is manufactured to a size to accommodate the product as shown by8and9. The cardboard pieces have score lines or slots5that enable the cardboard to be bend into a position shown as6and7. In synchronization with the movement of the product1, cardboards3and4are moved into a position where the are bent into U channel10where side sections12and13of the U are bend to an angle less than 90 degrees with the center part of the U form. As the product moves further on the conveyor, a guide11separates the sections12and13to an angle that will allow the U shaped cardboard to be pushed on the product1. Afterward the conveyor stops allowing the U channel to be pushed onto the product1. A pushing means such as an air cylinder can be used to push the cardboard U channel so the channel slides on to the product1. Guides11are removed, causing sections12and13to act like a spring clamp by pressing against the sides of the product1to maintain the cardboard in its proper position. An alternative to stopping the conveyor for pushing the The U channel, the U channel can be pushed onto the product while the conveyor is moving.

After the two cardboard pieces are placed in their proper position the conveyor moves the product to a film wrapping station17where a heat shrink film wraps the product with the card board. After wrapping the conveyor moves the product thru a heat tunnel station18where the film is heat shrunk around the product.

Any mechanical device capable of separating sections12and13and pushing the cardboard into its final position can be used. The lengths of sections12and13can be adjusted to allow for an opening so that users can see the product thru the heat shrink film. The cardboard can be substituted by any other material that will act to strengthen the stacking strength and have the mechanical ability to act as a spring clamp to maintain the material in its proper position on the moving conveyor.

FIG. 2shows a suction cup19picking up a cardboard sheet4and moving the sheet to the side of the conveyor in preparation for bending the cardboard. Suction cup19moves cardboard sheet4in synchronization with the movement of the product. Suction cups20and21bend the sides (flaps)12and13to an angle less than 90 degrees with the center part of the U form and then suction cups opens the bend sides greater than 90 degrees thereby allowing the suction cup19to push the cardboard onto the product. After the cardboard is pushed into the product, suction cups20and21pushes the sides against product and then releases the sides. The bend sides (flaps) presses against the product and remains in its final position on the conveyor.