US3793798A

US3793798A - Shrink palletized process and apparatus

Info

Publication number: US3793798A
Application number: US00295532A
Authority: US
Inventors: P Lancaster; W Lancaster
Original assignee: Lantech Inc
Current assignee: Lantech Inc
Priority date: 1972-10-06
Filing date: 1972-10-06
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

This invention provides a process for making a high-strength unitary package, which has its generally vertically arranged portion overwrapped by a sheet of material of a type laminateable at its heat-shrinking temperature wherein an overlapped laminated seal is simultaneously formed between the leading and trailing edges of the sheet when the overwrapping sheet is also heat shrunk tightly against the package. Basically, the process comprises the steps of: placing a package on a support; locating a generally vertically arranged rolled-up sheet of a material of a type laminateable at its heat-shrinking temperature on dispenser means mounted for movement relative to the support; withdrawing a leading edge of the material from the dispenser and holding that leading edge against the package; moving the dispenser means relative to the support about a generally vertical axis and thereby causing a sufficient amount of the material to be dispensed from the dispenser means to overwrap the generally vertically arranged portion of the package and also provide a section of the material overlapping the leading edge; severing the overlapping section from the dispenser means and holding it to the package in a position overlapping the leading edge; and heating the overwrapped package to the heat-shrinking temperature of the material and thus simultaneously forming an overlapping laiminated seal between the leading edge and the overlapping section and also heat shrinking the overwrapped material tightly against the package. The present invention is also directed toward the product that is produced by this process and to certain apparatus which can be utilized to perform this process.

Description

United States Patent [191 Lancaster, III et 'al.

[ Feb. 26, 1974 [5 SHRINK PALLETIZED PROCESS AND APPARATUS [75] Inventors: Patrick Lancaster, III; William G. Lancaster, both of Louisville, Ky.

[73] Assignee: Lantech, lnc., Louisville, Ky.

[22] Filed: Oct. 6, 1972 [21] Appl. No.: 295,532

[52] US. Cl 53/30, 53/184, 53/196 [51] Int. Cl B65b 53/02 [58] Field of Search... 53/30, 32, 33, 184, 196, 210,

[56] References Cited UNITED STATES PATENTS 3,514,920 6/1970 Hoffler et al. 53/184 x 3,589,102 6/1971 Zelnick Primary ExaminerRobert L, Spruill Attorney, Agent, or Firm -l-larry B. ODonnell, III

Zelnick 53/30 multaneously formed between the leading and trailing edges 'of the sheet when the overwrapping sheet is also heat shrunk tightly against the package. Basically, the process comprises the steps of: placing a package on a support; locating a generally vertically arranged rolled-up sheet of a material of a type laminateable at its heat-shrinking temperature on dispenser means mounted for movement relative to the support; withdrawing a leading edge of the material from the dispenser and holding that leading edge against the package; moving the dispenser means relative to the support about a generally vertical axis and thereby causing a sufficient amount of the material to be dispensed from the dispenser means to overwrap the generally vertically arranged portionof the package andalso provide a section of the material overlapping the leading edge; severing the overlapping section from the dispenser means and holding it to the package in a position overlapping the leading edge; and heating the overwrapped-package to the heat-shrinking temperature of the material and thus simultaneously forming an overlapping laiminated seal between the leading edge and the overlapping section and also heat shrinking the overwrapped material tightly against the package. The present invention is also directed toward the product that is produced by this process and to certain apparatus which can be utilized to perform this process.

34 Claims, 8 Drawing Figures iATENTEnrEazs mm SHEEI 1 [IF 2 Fig. 2

SHRINK PALLETIZEI) PROCESS AND APPARATUS BACKGROUND OF THE INVENTION I tus which can be utilized to perform the process.

In the past, various methods and apparatus have been utilized to provide a unitary package having its generally vertical portion overwrapped by a heat-shrunk material. Such methods are commonly referred to as I shrink palletizingto processes and basically comprise unitization of palletized package load by first overwrapping it with a heat-shrinkable material, which is' then tightly shrunk against the package by applying sufficient heat to the overwrapped package to raise its temperature to the heat-shrinking temperature of the over-wrapping material.

Heretofore the shrink palletizing method most commonly employed has required two coordinated operators who first took a pre-formed bag of the heatshrinkable material, next snapped the bag full of air, and then pulled the open end of the bag downwardly over the top of the palletized package load.

The prior-art has also provided rather expensive machines which permit only one operator to overslip the overwrapping bag. In any of these aforenoted prior-art systems, a bag is required which utilizes a considerably greater amount of overwrapping material than is actually needed, since it is well recognized that a satisfactory package can be provided by overwrapping only its generally vertically extended portion with the heatshrinkable material, whereas the bag provides unnecessary material which also overwraps the top of the package. See for example prior-art U. S. Pat. Nos.: 3,581,458; and 3,670,880.

In an effort to replace these aforenoted bag over-' wrap systems, the prior-art has also recently provided equipment for overwrapping the generally vertical portion of the package with sheet forms of the heatshrinkable material. One form of such prior-art sheet systems is described in detail in U. S. Pat. Nos. 3,590,549; 3,662,512 and 3,640,048, while another is described in detail in U. S. Pat. Nos. 3,514,920 and 3,626,654. I 1

Both of these prior-art sheet overwrap systems are complex in construction and/or difficult to operate in combination with conveying equipment that is frequently employed to move the packages from place to place, and are expensive to maintain. Furthermore, both of these prior-art sheet systems also require the provision and use of means, such as an adhesive or a heat-sealing iron, separate from those heater means utilized to heat-shrink the overwrapped material, to

provide a seal between the leading and' trailing edges of e the sheets of overwrapping material. And, with any of these previously known sheet systems, the quality of their edge seals has left a lot to be desired, there having been occasions of their breaking open following the performance of the subsequent separate heat-shrinking step. t

The present invention is particularly concerned with providing a process, which can be easily performed by only one operator, for making a high-strength unitary package which has its generally vertically arranged portion tightly overwrapped with a sheet of heat-shrunk material, wherein a high quality, overlapping laminated seal is also simultaneously formed between the leading and trailing edges of the overwrapping sheet when the overwrapping sheet is raised to its heat-shrinking temperature and heat-shrunk'tightly against the package.

SUMMARY OF THE INVENTION The present invention provides a process for making a high-strength unitary package, which has its generally vertically-arranged portion overwrapped by a'sheet of material of a type laminateable at its heat-shrinking temperature wherein an overlapped laminated seal is simultaneously formed between the leading and trailing edges of the sheet when the overwrapping sheet is also heat shrunk tightly against the package.

Basically,'the process comprises the steps of: placing a package on a support; locating a generally vertically arranged rolled-up sheet of a material of a type laminateable at its heat-shrinking temperature on dispenser means mounted for movement relative to the support;

withdrawing a leading edge of the material from the dispenser and holding that leading edge against the package; moving the dispenser means relative to the support about a generally vertical axis and thereby causing a sufficient amount of the material to be dispensed from the dispenser means to overwrap the generally vertically arranged portion of the package and also provide a section of the material overlapping the leading edge; severing the overlapping section from the dispenser means and holding it to the package in a position overlapping the leading edge; and heating the overwrapped package to the heat-shrinking temperature of the material and thus simultaneously forming an overlapping laminated seal between the leading edge and the overlapping section and also heat shrinking the overwrapped material tightly against the package.

The present invention is also directed toward the BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated in the accompanying drawing, wherein:

FIG. 1 is an elevational perspective view showing a presently preferred form of apparatus that can be utilized in performing the novel process of the present invention to produce its novel high-strength unitary package, which has its generally vertically arranged portion overwrapped by a sheet of material of a type laminateable at its heat-shrinking temperature wherein an overlapped laminated seal is simultaneously formed between the leading and trailing edges of the sheet when the overwrapping sheet is also heat shrunk tightly against the package, and illustrates its overwrapping sheet-dispenser means as located just following the commencement of the overwrapping operation;

FIG. 2 is an enlarged fragmentary top-plan view of the film overwrapping portion of the apparatus of FIG. 1, but illustrates the overwrapping film dispenser means as located just prior to the severance of the overlapping edge of the overwrapping sheet from the dispenser means;

FIG. 3 is a greatly enlarged fragmentary elevational view showing in detail the construction of the over wrapping film dispenser means and a presently preferred form of cutter means carried thereby for severing the overlapping edge of the sheet of overwrapped material from it;

FIG. 4 is a fragmentary elevational view showing in detail the construction of height-adjustable means which are provided on the dispenser means for mounting overwrapping sheets of various widths on the dispenser means to thus accomodate overwrapping of packages of various heights;

FIG. 5 is a fragmentary sectional view taken along line 55 of FIG. 3;

FIG. 6 is an enlarged fragmentary sectional view taken along line 66 of FIG. 3, and shows a detail of the construction of the cutter means;

FIG. 7 is a greatly enlarged fragmentary crosssectional view of the overlapped laminated seal that is simultaneously formed between the leading and trailing edges when the severed, overlapped, overwrapped sheet is heat shrunk tightly against the package during the heat-shrinking operation; and

FIG. 8 is a schematic diagram of a presently preferred form of electric control means that can be employed with the electrically powered drive means for the dispenser means of the apparatus shown in FIGS. 1-6.

DETAILED DESCRIPTION Referring now to the drawings, and more particularly to FIG. 1 thereof, there is illustrated in shadow lines a typical'product, a high-strength unitary package 10, which can be produced in accordance with the novel process that is provided in accordance with the present invention. While it should be understood that various means could be employed, FIGS. 1-8 of the drawings illustrate a form of apparatus 11 that has been used with good results in carrying out the novel process of the present invention to produce the product 10.

As further shown in FIG. 1, the product comprises a palletized load of plural boxes 12 built upon a skid 13 and has its generally vertically arranged portion overwrapped by a sheet of material 14 of a type that is laminateable at its heat-shrinking temperature, wherein an overlapped laminated seal 15 (shown in detail in FIG.

7) is simultaneously formed between the sheets leading edge 16 and trailing edge 17 when the overwrapped sheet 14 is also heat shrunk tightly against the package load 12.

As illustrated in FIGS. l-8,-the presently preferred form of apparatus 11 that can be employed to perform the process of the present invention to produce the product 10 basically includes non-rotatable support means, such as wheeled cart 18, for supporting the package load 12; dispenser means 19 for locating a generally vertically arranged rolled-up sheet of the material 14 for movement relative to the support means 18; drive means 20 for moving the dispenser means 19 relative to the support means 18 about a generally vertical axis 21 and thereby causing a sufficient amount of the material 14 to be dispensed from the dispenser means 19 to overwrap the generally vertically arranged portion of the package load 12 and also provide a section of material 17 overlapping the leading edge 16 of the material 14 and heater means 22 for heating the overwrapped package load 12 (FIG. 1 shadow lines) to the heat-shrinking temperature of the material 14 and thus simultaneously forming the overlapping laminated seal 15 between the leading edge 16 and the overlapping section or trailing edge 17 and also heat shrinking the overwrapped material 14 tightly against the package load 12 to provide the product 10.

As best shown in FIGS. 1 and 2, the cart 18 preferably has its wheels 18a located along two spaced-apart, generally parallel, and horizontal tracks 18b and thus conveyor means 18a and 18b are provided for moving the support means 18 relative to the heater means 22 along a substantially linear path.

And, as best illustrated in FIGS. I-6 and 8, the dispenser means 19 comprises a generally vertically arranged roller-mounting member 23 which is suspended from the outer end of a generally horizontally arranged arm 24 that has its inner end connected generally vertically arranged drive shaft 25. This drive shaft 25 has its axial-center aligned with the generally vertical axis 21 and is supported substantially centrally between the tracks 18b at a point sufficiently high to adequately clear the top of the tallest package load 12 to be over- ,wrapped on frame means including four spaced-apart generally vertical uprights 26a which are respectively interconnected by four generally horizontal frame members 26b to a housing 27 for enclosing a rotary bearing 28 for the drive shaft 25.

As further shown in FIGS. 1-6 and 8, the rollermounting member 23 is preferably constructed to accomodate two rollers 14a and 14b for respectively holding two different widths of rolled-up sheets of material 14. And as still further shown in detail in FIG. 4, the roller'mounting member 23 has its upper journal member 14c mounted for slideable vertical movement relative to it. This illustrated construction provides the dispenser means 19 with height-adjustable means 14c for mounting plural sheets of the overwrapping material 14 of various widths to thus accomodate overwrapping of package loads 12 of various heights. It also can permit simultaneously overwrapping of the package load 12 with plural sheets of material.

And, while it should be understood that various other means, such as scissors and the like, might be employed without departing from the spirit and scope of the present invention, the dispenser means 19 preferably carries cutter means for severing the trailing edge or edges 17 of the overwrapped sheet or sheets of the material 14 from the dispenser means 19. As best illustrated in FIGS. 2-3 and 5-6, these are preferably in the form of a drop knife 29 that is slidably mounted in a generally vertical, channel-like rail member 30 carried by the roller-mounting member 23 at a location intermediate of the two rollers 14a and 14b.

As yet further shown in FIGS. I-3 and 8, electrically powered drive means 20 are preferably provided for rotating the drive shaft 25 and thus moving the dispenser means 19 and its roller-mounting member 23 relative to the support means 18 about the generally vertical axis 21. The illustrated form of electrically powered drive means 20 includes an electric motor 31 which is mechanically interconnected through suitable reduction gearing 32 to the rotary drive shaft 25 and is supported by bracket means 33 at the intersection of the four generally horizontal frame members 26b. The motor 31 is connected across electrical power lines L and L by conductors 34, 35 and36 in electrical series with control means comprising a normally open electric switch 37, which can be closed by an operators foot.

While it should be understood that various-materials of a type which is laminateable at its heat-shrinking temperature may-be employed for the sheet of material 14, good results have been obtained in accordance with the present invention by employing polyetheylene film having thickness in a range between 0.00.1 and 0.016 inches. And, while it should be similarly understood that various forms of heaters can be employed without departing from the true spirit and scope of the present invention, good results have been obtained by utilizing infra-red heating means, similar to those described in detail in U. S. Pat. No. 3,493,724, in the absence'of any forced air circulating means, for the illustrated heater means 22 (FIG. 1).

It should also be understood that, while the leading and trailing

edges

16 and 17 of the sheet 14 can be manually held tightly against the package load 12 prior to heating the material 14 to its heat-shrinking temperature, they can also be held by removable, nonadhesive means, such as the weight 38 illustrated in FIG. 1, or by other mechanical means, such as staples and the like (not shown). As further shown in FIGS. 1 and 2, a part of the sheet 14 can also be wrapped over and heat-shrunk tightly against a portion of the top of the package load 12, in accordance with the present invention.

Basically, the novel process that is provided in accordance with the present invention comprises the steps of placing a package on a support; locating a generally vertically arranged rolled-up sheet of a material of a type laminateable at its heat-shrinking temperature on dispenser means mounted for movement relative to the support; withdrawing a leading edge of the material from the dispenser and holding that leading edge against the package; moving the dispenser means relative to the support about a generally vertical axis and thereby causing a sufficient amount of the material to be dispensed from the dispenser means to overwrap the generally vertically arranged portion of the package and also'provide a section of the material overlapping the leading edge, severing the overlapping section from the dispenser means and holding it to the package in a position overlapping the leading edge;and heating the overwrapped package to the heat-shrinking temperature of the material and thus simultaneously forming an overlapping material seal between the leading edge and the overlapping section and also heat-shrinking the overwrapped material tightly against the package.

To produce a product, such asthe illustrated highstength unitary package 10, by the novel process of the present invention with the illustrated apparatus 11, an operator first mounts at least one rolled-up sheet of the material 14, having a width sufficient to cover at least the vertical portion and preferably a part of the top of the package load 12, on the roller-mounting member 23 of the dispenser means 19.

Next, the operator moves the wheeled cart 18 supporting the package load 12 along the rails 18b to align its center beneath the generally vertical central axis 21 of the dispenser means drive shaft 25.

Then, the operator withdraws the leading edge 16 of the rolled-up sheet of material 14 from the dispenser means 19 and holds that leading edge 16 against the Next, the operator closes the normally open switch Y '37 with one of his feet, thus energizing the motor 31 and causing the dispenser means 19 to move relative to the support cart 13 and the package load 12 about the generally vertical axis 21, as shown by the circular arrows in FIGS. 1 and 2, to overwrap at least the generally vertically-arranged portion of the package load 12 and preferably a part of its top and also provide a section of material 17 for overwrapping the leading edge 16.

Then, the operator releases the switch 37 and the drop-knife cutter means 29 to stop the dispenser drive means 20 and sever the overlapping section or trailing edge 17 of the sheet 14 from the dispenser means 19 and holds the severed overlapping section 17 to the package load 12 in a position overlapping the leading edge 16, either manually or, preferably, by momentarily removing the weight 38 and replacing it in a position to accomplish this overlapping, but as yet unsealed, relationship between the sheet edges 16 and 17.

Finally, the operator raises the thus overwrapped package load 12 to the heat-shrinking temperature of the overwrapping material 14, as by rolling the wheeled cart 18 along the tracks 18b to the heater means 22,

and thus simultaneously causes the formation of the overlapping laminated seal 15 between the leading edge 16 and overlapping section or trailing edge 17 of the overwrapped material and also heat-shrinking the overwrapped material 14 tightly against the package load 12.

It should be apparent that while there has been described what is presently considered to be a presently preferred form of the present invention in accordance with the Patent Statutes, changes may be made in the disclosed process and product produced thereby without departing from the true spirit and scope of this invention.

Foe example, other equivalent forms of apparatus might be substituted for the illustrated apparatus 11. Various materials might be used for the material 14 so long as they are of a type that is laminateable at its heat-shrinking temperature. It is, therefore, intended that the appended claims shall cover such modifications and applications that may not depart from the true spirit and scope of the present invention.

What is claimed is:

1. A process for making a high-strength unitary package comprising the steps of:

a. placing a package on a support;

b. locating a generally vertically arranged rolled-up sheet of material of a type laminateable at its heatshrinking temperature on dispenser means I mounted for movement relative to said support; c. withdrawing a leading edge of said material from said dispenser means and holding said leading edge against said package;

(1. moving said dispenser means relative to said support about a generally vertically axis thereby causing a sufficient amount of said material to be dispensed from said dispenser means to overwrap the generally vertically arranged portion of said package and also provide a section of said material overlapping said leading edge;

e. severing said overlapping section from said dispenser means and'holding it to said package in a position overlapping said leading edge; and

f. heating said overwrapped package to the heatshrinking temperature of said material and thus simultaneously forming an overlapping laminated seal between said leading edge and said section and also heat-shrinking said overwrapped material tightly against said package.

2. The invention of claim 1, wherein said holding is accomplished with non-adhesive means.

3. The invention of claim 2, wherein a portion of said material is also held against a part of the top of said package prior to said heating.

4. The invention of claim 3, wherein said material comprises polyethylene.

5. The invention of claim 4, wherein said sheet comprises film having a thickness in a range between 0.001 and 0.016 inches.

6. The invention of claim 5, wherein said heating is performed with infra-red heating means.

7. The invention of claim 6, wherein said heating is performed in the absence of forced air circulation means.

8. The invention of claim 2, wherein said holding is performed manually.

9. The invention of claim 2, wherein said holding is performed by removable weight means.

10. The invention of claim 2, wherein said holding is performed with mechanical fastener means.

11. The invention of claim 1,.wherein said material comprises polyethylene.

'12. The invention of claim 11, wherein said material is film having a thickness in a range between 0.001 and 0.016 inches. i

13. The invention of claim 12, wherein said heating is performed with infra-red means.

14. The invention of claim 13, wherein said heating is performed in the absence of any forced air circulation means.

15. The invention of claim 11, wherein said heating is performed. with infra-red heating means.

16. The invention of claim 15, wherein said heating is performed in the absence of forced air circulating means.

17. The invention of claim 1, wherein said heating is performed with infra-red heating means.

18. The invention of claim 17, wherein said heating is performed in the absence of vforce air circulating means.

19. Apparatus for making a high-strength unitary package, comprising:

a. support means for supporting a package;

b. dispenser means for locating a generally verticallyarranged rolled-up sheet of material of a type laminateable at its heat-shrinking temperature for movement relative to said support means; c. means mounting said dispenser means for movement about a generally vertical axis;

d. drive means for moving said dispenser means relative to said support means about a generally vertical axis and thereby causing a sufficient amount of material to be dispensed from said dispenser means to overwrap the generally vertically-arranged portion of said package and also provide a section of said material overlappingthe leading edge of said material;

e. means for holding overlapping section of said package in a position overlapping but unsealed to said leading edge; and

f. heater means for heating said overwrapped package to the heat-shrinking temperature of said material and thus simultaneously forming an overlapping laminated seal between said leading edge and said section and also heat shrinking said overwrapped material tightly against said package.

20. The invention of claim 19 further including cutter means for severing said overlapping section from said dispenser means.

21. The invention of claim 20 wherein said means for holding said overlapping section .to said package in a position overlapping but unsealed to said leading edge is removable. i

22. The invention of claim 21, wherein said heater means comprise infra-red heating means.

23. The invention of claim 22, wherein said heater means are absent any forced air-circulating means.

24. The invention of claim 23, wherein said support means is non-rotatably mounted.

25. The invention of claim 24, wherein said drive means are powered by electric means energized and deenergized by a fooboperable electric switch.

26. The invention of claim 20, wherein said cutter means is carried by said dispenser means.

27. The invention of claim 21, wherein said removable means comprises weight means.

28. The invention of claim 19, further including conveyor means for moving said support means relative to said heater means.

29. The invention of claim 28, wherein said moving of said support means by said conveyor means is limited to a substantially linear path relative to said heater means.

30. The invention of claim 19, wherein said heater means comprises infra-red heating means.

31. The invention of claim 30, wherein said heater means are absent any forced air-circulating means.

32. The invention of claim 19 wherein said means for holding said overlapping section to said package in a position overlapping but unsealed to said leading edge is removable.

33. The invention of claim 32, wherein said removable means comprises-weight means.

34. The invention of claim 19, wherein said support means is non-rotatably. mounted.

Claims

1. A process for making a high-strength unitary package comprising the steps of: a. placing a package on a support; b. locating a generally vertically arranged rolled-up sheet of material of a type laminateable at its heat-shrinking temperature on dispenser means mounted for movement relative to said support; c. withdrawing a leading edge of said material from said dispenser means and holding said leading edge against said package; d. moving said dispenser means relative to said support about a generally vertically axis thereby causing a sufficient amount of said material to be dispensed from said dispenser means to overwrap the generally vertically arranged portion of said package and also provide a section of said material overlapping said leading edge; e. severing said overlapping section from said dispenser means and holding it to said package in a position overlapping said leading edge; and f. heating said overwrapped package to the heat-shrinking temperature of said material and thus simultaneously forming an overlapping laminated seal between said leading edge and said section and also heat-shrinking said overwrapped material tightly against said package.

4. The invention of claim 3, wherein said material comprises polyethylene.

8. The invention of claim 2, wherein said holding is performed manually.

11. The invention of claim 1, wherein said material comprises polyethylene.

12. The invention of claim 11, wherein said material is film having a thickness in a range between 0.001 and 0.016 inches.

15. The invention of claiM 11, wherein said heating is performed with infra-red heating means.

18. The invention of claim 17, wherein said heating is performed in the absence of force air circulating means.

19. Apparatus for making a high-strength unitary package, comprising: a. support means for supporting a package; b. dispenser means for locating a generally vertically-arranged rolled-up sheet of material of a type laminateable at its heat-shrinking temperature for movement relative to said support means; c. means mounting said dispenser means for movement about a generally vertical axis; d. drive means for moving said dispenser means relative to said support means about a generally vertical axis and thereby causing a sufficient amount of material to be dispensed from said dispenser means to overwrap the generally vertically-arranged portion of said package and also provide a section of said material overlapping the leading edge of said material; e. means for holding overlapping section of said package in a position overlapping but unsealed to said leading edge; and f. heater means for heating said overwrapped package to the heat-shrinking temperature of said material and thus simultaneously forming an overlapping laminated seal between said leading edge and said section and also heat shrinking said overwrapped material tightly against said package.

21. The invention of claim 20 wherein said means for holding said overlapping section to said package in a position overlapping but unsealed to said leading edge is removable.

25. The invention of claim 24, wherein said drive means are powered by electric means energized and deenergized by a foot-operable electric switch.

33. The invention of claim 32, wherein said removable means comprises weight means.

34. The invention of claim 19, wherein said support means is non-rotatably mounted.