GB1595530A - Shrink wrapping - Google Patents

Description

(54) SHRINK WRAPPING (71) We, UNION CARBIDE AU STRALIA LIMITED, a Company incorporated under the laws of the State of New South Wales, Commonwealth of Australia of 157-167 Liverpool Street, Sydney, N.S.W. Commonwealth of Australia, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to wrapping whereby a plurality of articles, such as bottles of drink or other containers or objects, may be grouped and firmly held together as a group for convenient carriage, storage or vending.

More particularly, the invention is concerned with a method of wrapping in which wrapping material is applied loosely to the group of articles and then shrunk to form a close envelope about the group. The wrapping material is a shrinkable plastics material and preferably a low density polyethylene uni-oriented shrink film.

According to the present invention there is provided a method of forming a shrink wrapping about a group of articles, comprising the steps: (a) placing a group of articles between two webs of shrinkable plastics material so that the group is enwrapped by the webs at one end of the group and across two opposite faces of the group, forming a transverse band out of the webs at the other end of the group by transversely heat sealing the webs together so that said band extends transversely across the other end of the group and portions of the webs not forming the band extend around the group longitudinally, (c) shrinking said portions and said band so that said portions become a closefitting enwrapment of the group, and (d) piercing said portions at least at one point between said band and said group, thus to enable the shrunken band to function as a handle for the carrying of the group.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which Figure 1 is a schematic side elevation of an assembly line in which the wrappings are applied to a group of bottles, Figure 2 is a perspective view showing a partly enwrapped group of three bottles which are also indicated at A in Figure 1, and Figures 3, 4 and 5 respectively illustrate stages in the final formation of the shrink wrapping and its handle.

Referring to Figure 1, bottles 12 arrive by way of a known kind of conveyor 13 (having back stop 14 and push feeder 15) in a thrusting station which places them, bottom end first, in groups of three, within a loop 16 formed, by join 17, from a pair of webs 18 and 19 of shrinkable plastics material. In this embodiment the width of the webs 18 and 19 is substantially equal to that of the group (A) of bottles 12 as indicated by dimension B in Figure 2. The webs 18 and 19 of plastics material may be fed in known manner from magazine reels indicated at 20 and 21.The group of bottles A thus emplaced within the loop 16 become longitudinally enveloped by the plastics material by transversely heat sealing (at 22) the webs together by way of vertically reciprocable bar heating elements indicated at 23, the group A of bottles being only longitudinally enveloped in the sense that they are now longitudinally encompassed by an openended tube or trunk 24 as shown in Figures 1 and 2.

The two webs are also transversely heat sealed together along a second line 25 due to operation of the heater elements 23. This second heat sealing 25 is of the kind which severs the webs and thus forms, at the same time, a separated encasement for the articles such as that indicated at 24. The line 25 also constitutes the base end of the next bottle-receiving loop to be made by forming the joint 17.

The breadth C of the band between lines 22 and 25 is so selected that the tensile strength of the band, in the direction of dimension B, is more than sufficient for the band, to become a container handle, reliably able to accept the loading due to the weight of the group of articles to be carried.

When the wrapping of the bottles has proceeded to the stage indicated by Figure 2, the partly wrapped groups proceed through a conventional shrink tunnel indicated at 26. Shrinkage of the applied wrapping causes the plastics material to bind the individual articles in the group tightly together and also causes the end portions 27 and 28 to be drawn together so that they then tightly curl about the ends of the group as indicated at 27A and 28A in Figure 3.

The shrunken wrappings may then be passed through a conventional cooling station as indicated at 29 and the wrappings thus formed are then pierced between the band formed between lines 22 and 25 and the group as indicated at 30 in Figure 4 by reciprocable chisel-like punches or blades as indicated at 31. The band constituting the material lying between lines 22 and 25 may then be bowed outwardly from the remainder of the wrapping so to constitute a carrier handle as shown at 32 in Figure 5.

It will be appreciated that piercing of the wrappings as referred to just above may be performed in many different ways. For example, by use of conventional air knives, or by use of thermal devices such as hot air, laser beam or heated blades.

WHAT WE CLAIM IS: 1. A method of forming a shrink wrapping about a group of articles, comprising the steps: (a) placing a group of articles between two webs of shrinkable plastics material so that the group is enwrapped by the webs at one end of the group and across two opposite faces of the group, (b) forming a transverse band out of the webs at the other end of the group by transversely heat sealing the webs together so that said band extends transversely across the other end of the group and portions of the webs not forming the band extend around the group longitudinally, (c) shrinking said portions and said band so that said portions become a closefitting enwrapment of the group, and (d) piercing said portions at least at one point between said band and said group, thus to enable the shrunken band to function as a handle for the carrying of the group.

2. A method as claimed in claim 1, wherein the two webs are heat sealed together at one end prior to placement of the group between the webs.

3. A method as claimed in claim 1 or claim 2, wherein said band is formed by heat sealing of said webs together along two parallel spaced-apart lines.

4. A method of forming a shrink wrapping about a group of articles, comprising the steps: (a) placing a group of articles within a loop formed by two webs of shrinkable plastics material having the webs joined together at one end so that the group is enwrapped by the webs at one end of the group and across two opposite faces of the group, (b) heat sealing together said webs at the other end of said group, along a first transverse line, thus fully to envelope the group longitudinally, (c) transversely heat sealing said webs together along a second transverse line spaced further from said group than said first line so to form a band longitudinally bounded by said lines, (d) separating said loop, including said band, from the non-wrapping remainder of said webs, (e) shrinking the separated loop, including said band, so that the loop becomes a close-fitting enwrapment of the group, and (f) piercing loop forming portions of both said original webs between said band and said group, thus to enable the shrunken band to function as a handle for the carrying of the group.

5. A method as claimed in claim 4, wherein the formation of said first and second transverse lines is performed simultaneously.

6. A method as claimed in claim 4, wherein the formation of said first and second transverse lines and the separation of said loop from said remainder of the webs are performed simultaneously.

7. A method as claimed in claim 4, wherein the formation of said first and second transverse lines, the separation of said loop from said remainder of the webs and the joining together of these ends of the webs from which said loop has been separated are performed simultaneously.

8. A method of forming a shrink wrapping about a group of articles substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. severs the webs and thus forms, at the same time, a separated encasement for the articles such as that indicated at 24. The line 25 also constitutes the base end of the next bottle-receiving loop to be made by forming the joint 17. The breadth C of the band between lines 22 and 25 is so selected that the tensile strength of the band, in the direction of dimension B, is more than sufficient for the band, to become a container handle, reliably able to accept the loading due to the weight of the group of articles to be carried. When the wrapping of the bottles has proceeded to the stage indicated by Figure 2, the partly wrapped groups proceed through a conventional shrink tunnel indicated at 26. Shrinkage of the applied wrapping causes the plastics material to bind the individual articles in the group tightly together and also causes the end portions 27 and 28 to be drawn together so that they then tightly curl about the ends of the group as indicated at 27A and 28A in Figure 3. The shrunken wrappings may then be passed through a conventional cooling station as indicated at 29 and the wrappings thus formed are then pierced between the band formed between lines 22 and 25 and the group as indicated at 30 in Figure 4 by reciprocable chisel-like punches or blades as indicated at 31. The band constituting the material lying between lines 22 and 25 may then be bowed outwardly from the remainder of the wrapping so to constitute a carrier handle as shown at 32 in Figure 5. It will be appreciated that piercing of the wrappings as referred to just above may be performed in many different ways. For example, by use of conventional air knives, or by use of thermal devices such as hot air, laser beam or heated blades. WHAT WE CLAIM IS:

1. A method of forming a shrink wrapping about a group of articles, comprising the steps: (a) placing a group of articles between two webs of shrinkable plastics material so that the group is enwrapped by the webs at one end of the group and across two opposite faces of the group, (b) forming a transverse band out of the webs at the other end of the group by transversely heat sealing the webs together so that said band extends transversely across the other end of the group and portions of the webs not forming the band extend around the group longitudinally, (c) shrinking said portions and said band so that said portions become a closefitting enwrapment of the group, and (d) piercing said portions at least at one point between said band and said group, thus to enable the shrunken band to function as a handle for the carrying of the group.

2. A method as claimed in claim 1, wherein the two webs are heat sealed together at one end prior to placement of the group between the webs.

3. A method as claimed in claim 1 or claim 2, wherein said band is formed by heat sealing of said webs together along two parallel spaced-apart lines.

4. A method of forming a shrink wrapping about a group of articles, comprising the steps: (a) placing a group of articles within a loop formed by two webs of shrinkable plastics material having the webs joined together at one end so that the group is enwrapped by the webs at one end of the group and across two opposite faces of the group, (b) heat sealing together said webs at the other end of said group, along a first transverse line, thus fully to envelope the group longitudinally, (c) transversely heat sealing said webs together along a second transverse line spaced further from said group than said first line so to form a band longitudinally bounded by said lines, (d) separating said loop, including said band, from the non-wrapping remainder of said webs, (e) shrinking the separated loop, including said band, so that the loop becomes a close-fitting enwrapment of the group, and (f) piercing loop forming portions of both said original webs between said band and said group, thus to enable the shrunken band to function as a handle for the carrying of the group.

5. A method as claimed in claim 4, wherein the formation of said first and second transverse lines is performed simultaneously.

6. A method as claimed in claim 4, wherein the formation of said first and second transverse lines and the separation of said loop from said remainder of the webs are performed simultaneously.

7. A method as claimed in claim 4, wherein the formation of said first and second transverse lines, the separation of said loop from said remainder of the webs and the joining together of these ends of the webs from which said loop has been separated are performed simultaneously.

8. A method of forming a shrink wrapping about a group of articles substantially as hereinbefore described with reference to the accompanying drawings.

9. A shrink wrapping whèn formed by a

method according to any of the preceding claims.