WRAPPING AND SECURING LOADS ON PALLETS

• US 3,807,126 A
• Filed: 02/19/1971
• Issued: 04/30/1974
• Est. Priority Date: 06/10/1970
• Status: Expired due to Term

• Current Assignee: Walter Schwarz
• Original Assignee: Walter Schwarz
• Inventors: Schwarz, Walter
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Desmond, E. F.
• Application Number:
  US05/116,936
• Time in Patent Office: 1,166 Days
• Field of Search: 53/30,184 34/225
• US Class Current: 53/442
• CPC Class Codes: B65B 53/06 supplied by gases, e.g. hot-air jets

Abstract

A method of and apparatus for wrapping a load on a pallet involving applying a bag of heat-shrinkable polyethylene film over the load and heating the bag in a heating chamber to effect shrinking of the bag. The bag is longer than the combined height of the load and the pallet so as to have mouth end portions which may extend down below the pallet. The pallet is raised to an elevated position in the chamber with the margin of its bottom surface clear for folding the bag mouth end portions thereunder. Hot air is blown downwardly in the chamber all around the bag and directed inwardly under the pallet to an air exit opening at the bottom of the chamber to blow the bag mouth end portions under the pallet for securing the bag to the pallet in place over the load on the pallet.

Claims

1. The method of wrapping and securing a load on a pallet comprising applying over the load a wrapper of a heat-shrinkable plastic film, the wrapper having lower end portions adapted to extend downwardly below the pallet, positioning the pallet, with the wrapper in place on the load on the pallet, in an operating position wherein the margin of the bottom surface of the pallet is clear for disposition of the said lower end portions of the wrapper thereunder, causing a flow of heated air downwardly over the wrapper on the outside of the wrapper and changing its direction thence to flow inwardly under the pallet, the air being blown downwardly in a relatively low velocity stream over the wrapper and in a relatively high velocity stream outwardly of the low velocity stream and inwardly under the pallet, the air flowing inwardly under the pallet blowing the lower end portions of the wrapper under the said margin of the bottom surface of the pallet and effecting heat shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, the air flowing downwardly over the wrapper effecting heat shrinking of the wrapper on the load, the shrinkage of the lower end portions of the wrapper under the said margin of the bottom surface of the pallet by said inwardly flowing air locking the wrapper in place over the load on the pallet generally before any shrinkage of the main body of the wrapper by the downwardly flowing air takes place.

2. The method of claim 1 wherein the wrapper is heated to a temperature sufficient to cause the lower end portions of the wrapper blown under the pallet to become heat-sealed

3. The method of claim 1 wherein the wrapper is a plastic bag applied in inverted position over the load, the mouth end portions of the bag being blown in by the air under the said margin of the bottom surface of the pallet.

4. The method of claim 3 wherein the pallet with the bag over the load thereon is elevated to the said operating position, the mouth end portion of the bag then hanging down below the level of the bottom surface of the pallet before being blown inwardly under the pallet.

5. The method of wrapping and securing a load on a pallet comprising applying over the load a wrapper of a heat-shrinkable plastic film, the wrapper having lower end portions adapted to extend downwardly below the pallet, positioning the pallet, with the wrapper in place on the load on the pallet, in an operating position wherein the margin of the bottom surface of the pallet is clear for disposition of the said lower end portions of the wrapper thereunder, causing a flow of heated air downwardly over the wrapper on the outside of the wrapper and changing its direction thence to flow inwardly under the pallet, the air flowing inwardly under the pallet blowing the lower end portions of the wrapper under the said margin of the bottom surface of the pallet and effecting heat shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, the air flowing downwardly over the wrapper effecting heat shrinking of the wrapper on the load, the shrinkage of the lower end portions of the wrapper under the said margin of the bottom surface of the pallet by said inwardly flowing air locking the wrapper in place over the load on the pallet generally before any shrinkage of the main body of the wrapper by the downwardly flowing air takes place, the wrapper being a plastic bag applied in inverted position over the load, the mouth end portions of the bag being blown in by the air under the said margin of the bottom surface of the pallet, the heating of the bag being effected by heating air and blowing it downwardly in a relatively low velocity stream over the bag and in a relatively high velocity stream outwardly of the low velocity stream and inwardly under the pallet, the pallet with the bag over the load thereon being elevated off a supporting means to the said operating position with the said margin of the bottom surface of the pallet clear for blowing in the mouth end portions of the bag under said margin, said mouth end portions of the bag hanging down below the level of the bottom surface of the pallet when the pallet is elevated off said supporting means, and the pallet being lowered back down onto said supporting means after the blowing in of said mouth end portions and the heating with resultant pressing down of said mouth end portions on said supporting means.

6. Apparatus for wrapping and securing a load on a pallet utilizing a wrapper of a heat-shrinkable plastic film applied over the load and having lower end portions adapted to extend downwardly below the pallet comprising means for positioning the pallet with the wrapper in place on the load on the pallet in an operating position wherein the margin of the bottom surface of the pallet is clear for disposition of the said lower end portions of the wrapper thereunder, and means for causing a flow of heated air downwardly over the wrapper on the outside of the wrapper and changing its direction thence to flow inwardly under the pallet, said flow-causing means comprising means including a blower for effecting blowing of air downwardly in a relatively low velocity stream over the wrapper and in a relatively high velocity stream outwardly of the low velocity stream and inwardly under the pallet, the air flowing inwardly under the pallet blowing the lower end portions of the wrapper under the said margin of the bottom surface of the pallet and effecting heat shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, the air flowing downwardly over the wrapper effecting heat shrinking of the wrapper on the load, the shrinkage of the lower end portions of the wrapper under the said margin of the bottom surface of the pallet by said inwardly flowing air locking the wrapper in place over the load on the pallet generally before any shrinkage of the main body of the wrapper by the downwardly flowing air takes place.

7. Apparatus as set forth in claim 6, comprising a chamber having a bottom with an air exit opening therein, said positioning means comprising a lift for raising the pallet adapted to hold the pallet in position above said air exit opening.

8. Apparatus for wrapping and securing a load on a pallet utilizing a wrapper of a heat-shrinkable plastic film applied over the load and having lower end portions adapted to extend downwardly below the pallet comprising means for positioning the pallet with the wrapper in place on the load on the pallet in an operating position wherein the margin of the bottom surface of the pallet is clear for dispostion of the said lower end portions of the wrapper thereunder, and means for causing a flow of heated air downwardly over the wrapper on the outside of the wrapper and changing its direction thence to flow inwardly under the pallet, the air flowing inwardly under the pallet blowing the lower end portions of the wrapper under the said margin of the bottom surface of the pallet and effecting heat shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, the air flowing downwardly over the wrapper effecting heat shrinking of the wrapper on the load, the shrinkage of the lower end portions of the wrapper under the said margin of the bottom surface of the pallet by said inwardly flowing air locking the wrapper in place over the load on the pallEt generally before any shrinkage of the main body of the wrapper by the downwardly flowing air takes place, said air flow means comprising means including a blower for causing said flow of air downwardly over the wrapper and thence inwardly under the pallet, means for heating the air, and a chamber having a bottom with an air exit opening therein, said positioning means being adapted to hold the pallet in position above said air exit opening, siad positioning means comprising a lift movable upwardly via said opening from a lowered retracted position at the bottom of the chamber to a raised position above said opening.

9. Apparatus as set forth in claim 8 wherein said chamber has at least one access opening, a closure for said opening, and a conveyor for transporting a loaded pallet with a wrapper thereon into position above the lift for being raised thereby to said operating position, and for transporting a pallet after heating of the wrapper out of the chamber.

10. Apparatus as set forth in claim 9 wherein said chamber has an entrance opening at one end thereof, an exit opening at its other end, closures for said openings, and a conveyor extending endwise through the bottom of the chamber for transporting a loaded pallet with a wrapper thereon from a station outside the entrance end of the chamber to a lift station in the chamber with the pallet above the lift and for transporting a pallet after heating of the wrapper from the lift station to a cooling station outside the exit end of the chamber.

11. Apparatus as set forth in claim 10 having means for indexing the conveyor to transport a pallet from station to station, means for opening the closures for transport of the pallets and closing the closures upon completion of each transport, means for operating the blower and the means for heating the air for a timed interval upon closing of the closure, means for actuating the closure opening means upon completion of said interval, and means for actuating said indexing means upon opening of the closures.

12. Apparatus as set forth in claim 6 comprising a heating chamber having a bottom, sides and a top, the bottom having an upper panel with an air exit opening therein for communication from the chamber to the space below said upper bottom panel, the sides having inside panels providing side air passages extending upwardly from the said space below the said upper bottom panel, the top having an inside lower panel with an air inlet opening therein, an air deflector, below said air inlet opening, a centrifugal air impeller below said inside lower top panel mounted for rotation on a generally vertical axis and postioned to draw in air through the inlet opening and blow it radially outward in respect to said axis, said air deflector being below said impeller and adapted in conjunction with the inside top panel and the inside side panels to cause the air to flow downwardly at the sides and ends of the chamber, said positioning means being adapted to support the pallet in position above said air exit opening.

13. The method of wrapping and securing a load on a pallet comprising applying over the load a wrapper of a heat-shrinkable plastic film, the wrapper having lower end portions adapted to extend downwardly below the pallet, positioning the pallet, with the wrapper in place on the load on the pallet, in an operating position wherein the margin of the bottom surface of the pallet is clear for disposition of the said lower end portions of the wrapper thereunder, causing a flow of air inwardly under the pallet to blow the lower end portions of the wrapper under the said margin on the bottom surface of the pallet and heating the wrapper to a temperature such as to effect shrinking of the wrapper on the load including shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, the wrapper being a plastic bag applied in inverted position over the load, tee mouth and end portions of the bag being blown in by the air under the said margin of the bottom surface of the pallet, the heating of the bag being effected by heating air and blowing it downwardly in a relatively low velocity stream over the bag and in a relatively high velocity stream outwardly of the low velocity stream and inwardly under the pallet, the mouth end portions of the bag blown under the pallet being heated and shrunk prior to the heating and shrinking of the remaining portions of the bag, and the air being heated to a temperature sufficient to cause the mouth end portions of the bag blown under the pallet to become heat-sealed together as well as shrunk, the pallet with the bag over the load being elevated off a supporting means to the said operating position with the said margin of the bottom surface of the pallet clear for blowing in the mouth end portions of the bag under said margin, said mouth end portions of the bag hanging down below the level of the bottom surface of the pallet when the pallet is elevated off said supporting means, and the pallet being lowered back down onto said supporting means after the blowing in of said mouth end portions and the heating with resultant pressing down of said mouth end portions on said supporting means.

14. Apparatus for wrapping and securing a load on a pallet utilizing a wrapper of a heat-shrinkable plastic film applied over the load and having lower end portions adapted to extend downwardly below the pallet comprising means for positioning the pallet with the wrapper in place on the load on the pallet in an operating position wherein the margin of the bottom surface of the pallet is clear for disposition of the said lower end portions of the wrapper thereunder, and means for causing a flow of air inwardly under the pallet to blow the lower end portions of the wrapper under the said margin of the bottom surface of the pallet and for heating the wrapper to a temperature such as to effect shrinking of the wrapper on the load including shrinking of said lower end portions of the wrapper underneath the pallet to secure the wrapper to the pallet, said air flow means comprising means including a blower for causing said flow of air downwardly over the wrapper and thence inwardly under the pallet, means for heating the air, said apparatus comprising a chamber having a bottom with an air exit opening therein, said positioning means being adapted to hold the pallet in position above said air exit opening, and said positioning means comprising a lift movable upwardly via said opening from a lowered retracted position at the bottom of the chamber to a raised positioned above said opening.

15. Apparatus as set forth in claim 14 wherein said chamber has at least one access opening, a closure for said opening, and a conveyor for transporting a loaded pallet with a wrapper thereon into position above the lift for being raised thereby to said operating position, and for transporting a pallet after heating of the wrapper out of the chamber.

16. Apparatus as set forth in claim 15 wherein said chamber has an entrance opening at one end thereof, an exit opening at its other end, closures for said openings, and a conveyor extending endwise through the bottom of the chamber for transporting a loaded pallet with a wrapper thereon from a station outside the entrance end of the chamber to a lift station in the chamber with the pallet above the lift and for transporting a pallet after heating of the wrapper from the lift station to a cooling station outside the exit end of the chamber.

17. Apparatus as set forth in claim 16 having means for indexing the conveyor to transport a pallet from station to station, means for opening the closures for transport of the pallets and closing the closures upon completion of each transport, means for operating the blower and the means for heating the air for a timed interval upon closing of the closures, means for actuating the closure opening means upon completion of said interval, and means for actuating said indexing means upon opening of the closUres.