GB2031833A

GB2031833A - Device for holding a number of containers

Info

Publication number: GB2031833A
Application number: GB7908714A
Authority: GB
Original assignee: PLG Research Ltd
Current assignee: PLG Research Ltd
Priority date: 1978-10-16
Filing date: 1979-03-13
Publication date: 1980-04-30
Also published as: GB2073090A; JPH0132060B2; ES257386U; ES257385Y; SU973005A3; ES257386Y; MY104847A; GB2031833B; ES257385U; ZA795384B; JPS5590337A; BE879294A; GB2073090B

Abstract

The plastics material device 6 has a plurality of generally quadrilateral openings 8 for receiving and gripping the containers 9, the openings 8 having their sides formed by strips 5, 10, each of the strips 5 of two opposite, corresponding sides of each opening being orientated along their length, the strips 10 of the remaining two opposite sides not being substantially orientated. The strips 5, at least, have substantial elasticity. The device may be made by forming holes or depressions in a plastics web and then stretching the web longitudinally to orientate just the strips 5 and to form the holes or depressions into the openings 8. <IMAGE>

Description

SPECIFICATION Device for holding a number of containers Background of the invention Various devices are known for holding a plurality of containers together. In one instance, a bottle combining unit holding four or six bottles of beer in a firm state has been made using cardboard overwraps.

In another instance, unorientated plastics sheet material has had circular openings punched into it for receiving and gripping beer cans. In general, the containers should be held tightly together whilst not being -allowed to come into actual contact.

The verb "orientate" as used herein means "molecularly orientate" and derived words such as "unorientated" and "orientated" have equivalent meanings.

The invention The invention provides the devices set forth in Claims 1 and 20, the method set forth in Claim 12, the bands set forth in Claims 10 and 21, the pack set forth in Claim 25 and the packaging method set forth in Claim 28.

Claims 2 to 9, 11, 13 to 17, 26 and 27 set forth preferred features of the invention.

Using the invention, the containers can be held together very firmly but prevented from touching each other at the location of the device. It has been found that the generally quadrilateral openings and the strips (which will be wider than they are thick) can cause the majority or almost all of the plastics material of the device to be put under tension and stretched elastically (though some plastic deformation may also occur) when the containers are inserted, provided the openings are correctly sized. Thus when the device is forced over the containers, the elastic strips are easily deformed to fit snugly around the container and two opposite strips will twist so that their centre parts lie flat against the container (instead of merely lipping up with localised stretching of the margins of the openings).When the devices are in the form of a continuous band, the procedure can be facilitated by putting the band under longitudinal tension and the longitudinal strips will take up the curvature of the container sides and whilst doing so apply tension to the transverse strips, which may themselves be subjected to very little extension.

It is stated herein that certain of the strips have substantial elasticity. This means that when they are stretched to a small extent, e.g. to produce an extension of the order of 5%, and held stretched to that extent, a substantial or high force must be applied and continue to be applied. Considerable plastic (i.e. non-elastic) deformation is tolerable as long as sufficient elastic deformation also occurs. Furthermore the elastic force applied after extension has occurred may decrease somewhat. The intention is that the elastic force applied by the strips should hold the pack of containers rigidly together when the containers have been inserted in the openings. The plastics material must be chosen accordingly.

Although the elasticity of plastics material, both unorientated and orientated, varies significantly from material to material, these properties are easily ascertainable. It is found that a low density polyethylene such as "Sclair", manufactured by Du Pont of Canada, is suitable and exhibits better elastic properties after orientation than it does before orientation.

The plastics material device can be of light weight and of very low cost. The low cost enables two such devices to be used without excessive expenditure; for instance in the case of beer bottles, one device can be towards the top of the bottles and the other towards the base. However it would be possible to use just one device in suitable circumstances, for instance when holding beer cans together.

The device of the invention can be made as set forth in Claim 12. The starting material is preferably not orientated, though melt orientation may have occurred. It is believed advantageous to avoid orientating two opposite sides of the openings because the unorientated plastics material gives added stability to the eventual pack. In addition, if the initial holes are formed by punching, the punched out pieces are smaller and are not orientated, which facilitates both punching and reclaiming the plastics material. Theoretical considerations and further details such as possible shapes of the holes or depressions are given in the specification of British Patent Application No. 40641/78, a copy of which is filed herewith.

The starting sheet material can be of any thickness, including low thicknesses which are normally referred to as films; furthermore, though the sheet material is preferably planar on each face, this is not necessarily so. If depressions, rather than holes, are formed in the starting material for the method of Claim 12, the depressions must be such that they rupture when the material is stretched.

The strips need not be parallel-sided, though substantially parallel-sided strips are preferred.

Description ofpreferred embodiments The invention will be further described, by way of example, with reference to the accompanying drawings, in which Figure 1 is a plan view of part of some starting material for a method in accordance with the invention; Figure 2 is a plan view of part of a band of container holding devices in accordance with the invention, the positions of the containers being indicated; Figure 3 is a side view of containers packs made using the devices of Figure 2; Figure 4 is a plan view of the packs of Figure 3; and Figure 5 is a plan view of part of another band of container holding devices in accordance with the invention.

Though many different plastics materials and different thicknesses can be used, the starting material 1 shown in Figure 1 can be of a low density polyethylene (say 0.918 gm/cc.) and have a thickness of about 0.5 mm. The starting plastics material can have some elasticity, and is preferably unorientated. As can be seen, the plastics sheet material 1 has groups of four main holes 2 whose centres are on a rectangular grid. The main holes 2 are long-shaped with their major axes at right angles to the longitudinal or machine direction, which runs up and down the page. In the transverse direction, there is a further hole 3 between each pair of main holes 2, and its transverse dimension is substantially less than that of the main holes 2. Each group of main holes 2 is separated from the next group by holes or (as shown) slits 4 which have circular holes at each end to prevent splitting.In general, the holes or slits 4 should be long-shaped with their major axes in the transverse direction. The holes or slits 2,3 and 4 can be formed by punching or in any other suitable manner, or could be merely depressions.

The sheet material 1 is in the form of a long band, and the band is stretched in the machine direction (indicated by the double-headed arrow in Figure 1) in any suitable manner. In practice, the stretching can be effected in a hot water bath using differential speed rolls. The stretch ratio can be chosen in accordance with the plastic used and the strength required, but suitable stretch ratios are for instance between 1:5 and 1:8, as measured across the holes, i.e. comparing the dimension a in Figure 1 with the dimension A in Figure 2.

During this stretching, the zones at the sides of the holes 2,3 are orientated and drawn into longitudinal strips 5. For clarity, these zones are shown cross-hatched in Figure 1. It will be seen that the zones between the slit-shaped holes 4 and on the outside of the slit-shaped holes 4 are not stretched.

Looking at Figure 2, which shows the stretched band, the band is formed of an integral succession of devices 6 for holding a plurality of containers together. In the instance shown, four containers are to be held together, but it can be seen that with simple modification, two containers or six containers or other suitable numbers could be held together. The devices 6 are joined to each other by parts 7 in the line of the slits 4.

In each device there is a plurality of generally quadrilateral openings 8 on a rectangular or square grid, which have been formed from the main holes 2 and which are for receiving and gripping the respective containers, shown as squat beer bottles 9 in Figure 3. As can be seen in Figure 2, each opening 8 has its sides formed by strips, the longitudinal strips 5 being orientated along their length and the transverse strips 10 not being substantially orientated. The longitudinal strips 5 are substantially longer than the transverse strips 10.

In Figure 2, the hatching indicates where the thickness of the plastic increases on passing from orientated plastic to unorientated plastic, and the hatching lines run up the slope. It will be seen that the orientated strips 5 of one opening are aligned with the orientated strips 5 of the next opening and that the orientation passes from the end of one strip into the end of the aligned strip, in the same device 6. Furthermore, the orientation of the strips 5 continues beyond the corners of the openings 8. Orientation itself increases the strength of the plastic, and by continuing the orientation beyond the corners of the opeings 8 the transition between the orientated plastic and the unorientated plastic is strengthened.

It will be seen that the orientated, longitudinal strips 5 give the band shown in Figure 2 significant strength in the machine direction and also give the sides of the openings 8 good elastic properties. Due to their greater bulk, the unorientated, transverse strips 10 stop the bottles 9 contacting each other and clinking. The sizes of the openings 8 are such that some elastic stretching of the sides is required in order to receive the bottles 9. In general, it is believed that the longitudinal strips 5 should be extended by 2 or 3% up to 15% on inserting the bottles 9, a preferred range being 5% to 10%. The force required to hold the strips 5 so extended is a force of the order of 1 Kg wt., e.g. 0.4 to to 2 Kg wt.

In theory, it would be possible to form the band shown in Figure 2 by suitable formation of the initial holes and stretching the plastics material in two directions at right angles, either simultaneously or sequentially.

This however is not preferred because it would be more difficult to produce accurately-sized openings 8 and because the transverse stretching would be expensive.

In order to pack the bottles 9, the bottles 9 are two-by-two e.g. touching one another along a conveyor. The devices 6 are provided in the form of a continuously-moving band which is under longitudinal tension, and which can come from a roll; the band is pressed down over the tops of the bottles 9 to grip the bodies of the bottles 9. Figure 2 generally indicates the positions of the bottles 9, before pressing the band down.

Subsequently a second band is pressed down over the bottles 9, to grip the bodies of the bottles 9 above the level of the first band. The shape of the bottles 9 shown in Figure 3 makes it more desirable to push both hands on from the top because the relatively small diameter at the neck of the bottle 9 facilitates entry into the openings 8 of the device, and in this case both bands can be identical. However, in other cases, it may be preferred to push one band on from the top and the other band from the bottom. In this latter case, it may be necessary to have the openings 8 in the lower band somewhat larger because it may be more difficult to force the lower band over the bottles as there is no tapered section to facilitate entry.

As shown in Figures 3 and 4, the longitudinal strips 5 twist round so that the centre part of each strip lies flat against the sides of the container. For this reason, there are two spaced, parallel strips 5 in the centre zone, though Figure 5 shows that a single central strip 5 can be used, if desired, and the single strip 5 will twist round.

Preferably, the outer strips 5 have to stretch to a greater extent than the inner strips 5, to hold the pack firmly together with pairs of bottles 9 pulled towards each other and merely separated by the thickness of the two strips 5, (or just one strip 5 in the Figure 5 device). To arrange this, the centres of the bottles 9 are slightly outside the centres of the original openings 8. In addition, to pull the pairs of bottles 9 towards each other, .the outer strips 5 are wider than the inner strips 5, i.e. the outer strips 5 have a larger cross-sectional area than the inner strips 5 and apply a larger force than the inner strips 5 for the same extension.

By lying flat against the sides of the bottles 9, the strips 5 hold the bottles 9 more firmly than they would if they were on their edges, and in addition the major part of the material of the band is stretched elastically; in practice one can stretch all the material except that at the corners of the device and at the intersections of the longitudinal strips 5 and transverse strips 10. Figure 4 shows a gap at the inner corners of each opening 8 but not at the outer cornets, and this is preferred. However, there could also be gaps at the outer corners or alternatively no gaps at all. The individual packs can subsequently be parted by slitting along the parts 7. In the final pack, all the strips 5, 10 are under tension in the direction oftheiriength.

- If desired, a U-fold (not shown) can be formed in the central longitudinal strip 5 in Figure 5 to provide a greater thickness of material between adjacent bottles 9.

The strips 10 adjacent the slits 4 could be longer, to form handles for holding the packs or tags for carrying advertising matter.

Example In general this Example is a typical example for a starting material made of extruded, unorientated "Sclair" having a uniform thickness of 0.5 mm. All distances are in mm and all forces are in Kg. wt.

Outer strips Inner strips 5 5 Strip width before stretching (distance.

between edges of holes 2 and 3 in Figure 1) 9.5 6.4 Strip width after stretching (at narrowest point) 4.8 3.2 Strip thickness after stretching 0.18 0.20 Strip length before stretching (a in Figure 1) 9.5 Strip length after stretching (A in Figure 2) 50.8 Stretch ratio 5.3:1 Static force required to produce 5% extension 0.75 0.5 Static force required to produce 10% extension 1.4 1.0 Static force required to produce 15% extension 1.75 1.5 The forces noted above dropped by a value of from 0.1 to 0.15 Kg wt. on holding the strips 5 extended.

Claims

1. A device for holding a plurality of containers together, comprising an integral piece of plastics material which has a plurality of generally quadrilateral openings for receiving and gripping the respective containers, the openings having their sides defined by strips, the strips defining two opposite, corresponding sides of each opening being orientated in the direction of their length and having substantial elasticity and the strips defining the remaining two sides not being substantially orientated.

2. The device of Claim 1, wherein the orientation of the orientated strips is continued beyond the corners of the openings.

3. The device of Claim 2, wherein the orientated strips of one opening are aligned with the orientated strips of another opening and in each case the orientation passes from the end of one strip into the end of the aligned strip.

4. The device of any one of the preceding Claims, wherein two adjacent openings are separated by two parallel, spaced strips.

5. The device of Claim 4, wherein each separating strip is orientated in the direction of its length.

6. The device of Claims 3 and 4, for holding at least four containers together, and having at least four of the container receiving openings with their centres on a rectangular or square grid, two pairs of parallel, spaced separating strips separating respective pairs of the openings and the separating strip of one pair being aligned with the separating strip of the other pair with the orientation passing from the end of one strip into the aligned strip.

7. The device of Claim 6, wherein, in the other direction, respective pairs of the openings are separated by single, substantially unorientated strips.

8. The device of any one of the preceding Claims, wherein the openings are generally rectangular, the strips forming two opposite sides being substantially longer than those forming the remaining two sides.

9. The device of any one of the preceding Claims, wherein there are at least three of the orientated strips defining two side-by-side openings, the outer strips having a larger cross-sectional area than the inner strips.

10. A band of plastics material, comprising an integral succession of devices of any one of the preceding Claims, the strips which extend longitudinally of the band being orientated in the direction of their lengths.

11. The band of Claim 10, wherein the devices are those of Claim 8 and the longer strips extend longitudinally of the band.

12. A method of making a device for holding a plurality of containers together, comprising forming a plurality of holes or depressions in plastics sheet material which when orientated has substantial elasticity, and then stretching the material to orientate and draw into strips zones at the sides of the holes or depressions and to form the holes or depressions into openings for receiving and gripping the containers.

13. The method of Claim 12, wherein the holes or depressions are long-shaped with their major axes at right angles to the direction of stretching, the material being stretched in only one direction.

14. The method of Claim 12 or 13, wherein there are two main holes or depressions whose centres are on a line at right angles to the direction of stretching, for forming the container receiving openings, and between the holes or depressions there is a hole or depression whose dimension parallel to said line is substantially less than that of the main holes or depressions.

15. The method of any one of Claims 12 to 14, wherein the plastics sheet material is in the form of a long band and is formed with holes or depressions for making a succession of the devices, the stretching being longitudinally of the band.

16. The method of Claim 15, wherein the individual devices are separated on the band by zones including slits, holes or depressions, the stretching being insufficient to cause the latter zones to orientate.

17. The method of Claim 16, wherein the latter slits holes or depressions are long-shaped and have their major axes at right angles to the longitudinal direction.

18. A method of making a device for holding at least two containers together, substantially as herein described with reference to the accompanying drawings.

19. The method of Claim 18, and substantially as described in the Example.

20. A device for holding at least two containers together, made by the method of any one of Claims 12 to 17.

21. A band of plastics material, comprising an integral succession of devices each of which is for holding a plurality of containers together, made by the method of any one of Claims 15 to 17.

22. A device for holding at least two containers together, substantially as herein described with reference to, and as shown in, Figures 1 to 4 or Figures 2 to 4 or Figure 5 of the accompanying drawings.

23. The device of Claim 22, and substantially as described in the Example.

24. A band comprising an integral succession of devices each for holding at least two containers together, substantially as herein described with reference to, and as shown in, Figure 2 or Figure 5 of the accompanying drawings.

25. A pack of at least two containers held together by at least one device of any one of Claims 1 to 9, 20, 22 and 23 with the containers received in and gripped by the respective openings, all the strips being under tension and the strips of at least two opposite, corresponding sides being twisted so that the centre part of the strip lies flat against the side of the respective container.

26. The pack of Claim 25, wherein pairs of containers are pulled towards each other and are only separated by some of the orientated strips.

27. The pack of Claim 25 or 26, wherein there are two of the devices one spaced above the other and parallel to each other, each device holding all the containers together.

28. A method of packing containers, comprising assembling the containers in groups and then applying to the containers at least one band of any one of Claims 10, 11, 21 and 24 so that the containers are received in the respective openings and are gripped by the sides of the openings, the groups of containers subsequently being separated by dividing the band between the groups.