GB2050923A - Moulded plastics body separable into individual consumer articles - Google Patents

Abstract

A plate (1) of plastics material is formed e.g. by extrusion and rolling with a number of grooves (3) which define residual thin webs (4) so that consumer articles, e.g. hoops for supporting tunnel cloches or U-shaped pegs (25, 26,) for pegging sheets (27) to the ground (28), or price tags for foodstuffs, or recesses for eating implements in plate shaped picnic packs, can easily be separated from the plate by tearing or breaking off, at least after an initial cut or tear. The ends (6) of the plate can be cut at an angle 7 so that the articles have pointed ends. Recesses 19 may be pressed into the articles during formation of the plate so that the articles bend preferentially at selected points. <IMAGE>

Description

SPECIFICATION Plastics body separable into individual consumer articles, method of manufacturing such a body and uses of such a body The process for manufacturing consumer articles from plastics that has been most widely used hitherto is the injection moulding process. In this process a substantial number of articles are moulded simultaneously in an injection mould.

The plastics material is injected or forced into the mould in a molten condition and distributed to the individual cavities by runner passages. When the plastics material has solidified the individual articles and the runners form a one-piece but markedly branched body. The articles are separated from the runners and the latter are treated as waste material and mixed back into the raw material for the next charge. Generally the separation is carried out by the manufacturer but it is also known to leave this step to the distributor or even the ultimate user. A body produced in a moulding process always has the same number of articles on it and so counting of them, which is tiresome and often leads to errors, is unnecessary.

However the process does have certain drawbacks. The moulds themselves are very expensive.

The process is therefore only suitable for production on a very large scale and modifications to the shape are virtually impossible. Moreover the process is a cyclic one, with a limited rate of operation. The material of the runners must be collected together and fed back into the raw material in the correct proportions. Damage by heat resulting from the repeated melting and unwanted discolouration are amongst the factors which put up the cost of the manufacturing process. Where the plastics body is handled commercially as one-piece body as removed from the mould, a number of drawbacks must likewise be taken into account, such as inconvenient bulk, loss of the material of the runners, and poorly executed separation of the individual articles from the runners.

The aim of the invention is to provide a body of plastics material which can be separated intó the individual articles and which is economical to manufacture and can be used as a supply package for a predetermined number of articles, and which has as few as possible of the drawbacks of the injection moulding process.

According to the invention a body which can be separated into individual articles is in the form of a plate of synthetic resin in which the individual articles are separated from one another by means of channel-shaped grooves penetrating nearly through the thickness of the plate to leave only residual thin webs.

The resulting articles are preferably of elongated shape. In order to allow the articles to be inserted for example into the ground or into another substrate giving support, such as polystyrene foam plates, soft food items, e.g. cheese or vegetables, for indicating the price or the like, the articles can have pointed ends. The articles can be capable of separation for example by hand, at the webs and in one embodiment the articles are of elongated form and are capable of being shaped, for example bent into an arc, to form attachment hoops of which both ends can be stuck into the ground.

The body according to the invention, separable into individual articles, can conveniently be used as a sales pack comprising a predetermined known number of articles.

The invention is further explained in the following by way of example in conjunction with the drawings, in which: Figure 1 shows a plastics body capable of separation into individual articles, Figure2 is a section on the line I-I in Figure 1; Figure 3 is a side elevation of an individual article according to Figure 1, showing a particular field of use; Figure 4 is a detail view in section of an individual article of Figure 1, showing another field of use; Figure 5 shows a further body capable of being separated into individual articles; Figure 6 is a section on the line Il-Il in Figure 5; Figure 7 shows apparatus for manufacturing a body according to the invention, looking in the direction of production; Figure 8 is a side view of an individual article according to Figure 5, showing a further field of use; and Figure 9 shows another body according to the invention, separable into individual articles.

The body of plastics material illustrated in Figures 1 and 2 comprises a plate 1 of high polymer synthetic resin in which the consumer articles 2 are separated from one another by means of channelshaped grooves 3. The latter penetrate nearly right through the thickness of the plate to leave only residual thin webs 4 which can indeed be cut right through at portions 4a of the grooves 3, in order to ease separation of the individual articles 2. The webs 4 have a strength such that, once a tear or cut has been started, the webs can easily be manually torn or broken right through. However, it is open to the user to employ scissors or a knife to cut through the webs 4. In this case the grooves 3 serve as guides for the cutting blade.It is thus possible, without there being apertured portions 4a, for the individual articles to be separated with accuracy as to shape by hand by means of a knife, by simply following the grooves 3. There is no waste of material.

In the particular embodiment illustrated in Figure 1 the plate 1 has the shape of an acute-angled parallelogram and the grooves 3 extend parallel to one another and to two opposite edges of the parallelogram. Consequently the other edges 5 and 6 intersect the grooves 3 at an acute angle 7, for example of less than 45 . This results in the formation of strip-shaped or bar-shaped articles 2 with points 8 at both ends. By choosing a suitably tough and rigid plastics material it is possible in this way to produce, for example, plant supports, supporting hoops for the covering material of plastics tunnel cloches used in horticulture, or the like. Figure 3 shows a side view of an article 2 shaped to form a supporting hoop 9 of which both ends 8 are inserted in the ground 10.The plate 1 thus forms a flat pack comprising a predetermined known number of such supports 9.

As an example for the manufacture of a plastics body according to the invention the plate 1 would be manufactured from polypropylene for the use referred to above. In a manner known in itself, a continuous strip 11 having a thickness of, for example 5 to 6 mm, is extruded continuously from a wide slot-shaped extrusion nozzle. Whilst this web is still in a warm and plastic condition a grooving roller, not shown, is used to impress grooves 3 extending parallel to the direction of extrusion and at a mutual spacing of for example 12 to 25 mm. Atthe base of each groove 3 there remains a thin longitudinally extending web of plastics having a thickness of for example 0.01 to 1 mm, preferably between 0.05 and 0.2 mm and a width of for example 0.5 to 1 mm. The width of the extruded strip depends on the number of articles 2 which are to be included in a pack.At spacings of for example 50 cam to 2 m, according to the length of the articles 2 which is desired, the strip 11 is cut along lines, corresponding to the above-mentioned edges 5 and 6, into plates 1 of rhomboidal shape. However it could be cut into substantially rectangular plates 1, the sharp ends 8 of the articles 2 being produced by the cut being of saw-tooth profile 12, for example produced by stamping, as indicated on the right hand side of Figure 1. The webs 4 in the grooves 3 can be cut right through over a greater or lesser extent (4a) according to the judgement of the manufacturer, without entirely breaking the interconnection between the articles 2 making up a plate 1. It is obviously possible to extrude strips 11 of double or multiple width and then to separate them into strips of narrower width by completely cutting through selected grooves.

The articles 2 could also be used in groups without cutting through the webs 4 that interconnect them.

In connection with their use as supporting hoops for tunnel cloches, it is for example possible to separate off two articles 2, still connected together, to form the end hoop. Byfolding about the webs 4, hoops9 of double thickness can be produced. At the same time the edge of a covering sheet 13 can be clamped between the two articles 2 as illustrated in Figure 4.

Figures 5 and 6 illustrate a further embodiment of a body according to the invention. The body serves as a pack to form a predetermined number of staple-like securing elements or pegs for sheet-like coverings such as mulch covers, plant-protecting sheets, tunnel cloches, mats for protection against erosion, bird proof nets and so on. The manufacture is analogous to that of the embodiment described earlier. For example a strip of polypropylene having a thickness of for example 3 mm, generally about 1.5 to 5 mm, and any desired width, is extruded and, as described above, provided with channel-shaped grooves 15 and then cut into plates 17 by transverse cuts 16. The grooves 15 separate the plates 17 into strips 18 having a width of, for example 10 mm and generally between 6 and 15 mm. Further recesses 19 are impressed simultaneously with the channelshaped grooves 15.The impression of the grooves 15 and recesses 19 is illustrated diagrammatically in Figure 7. A continuously extruded strip of plastics material is fed, still in its warm and plastic condition, through a pair of rollers formed by a stamping roller 20 and a counter-roller 21 having a smooth resilient surface. The stamping roller 20 has regularly spaced radially projecting circumferential ridge-like or knifeshaped raised portions 22 by means of which the grooves 15 are formed. Between the raised portions 22 are circumferentially spaced further projections 23 by which the recesses 19 are formed. As shown in Figure 7, between the ridge-like portions 22 and the projections 23 there is a web 19a forming a continuation of the sides of the grooves 15. This has the effect of keeping the grooves 15 separate from the recesses 19.The significance of this step is that on separating a strip 18 the tearing or cutting follows the grooves 15 and does not become diverted transversely through the recesses 19.

The recesses 19 have the effect of weakening the cross-section of the strip 18 at pre-determined points. When the strip 18 is bent, these points form sharp bends 24. The arrangement of the adjacent webs 19a of plastics in pairs has the effect that the bending necessarily takes place out of the plane of the plate. Thus the strips 17 can form staple-like U-shaped securing elements or pegs, with a flat central portion 25 and two perpendicular limbs 26.

The ends of the limbs 26 are cut to a sharp form by the above-mentioned inclined cutting of the plates, so that it is made easy to stick the article through a covering sheet 27 and into the ground 28. The residual web of plastics material in the grooves 15 can be cut right through at intervals. The recesses 19 could also be in the form of holes extending right through the plate.

The grooves do not need to be straight. Figure 9 shows an arrangement in which securing elements 30 are formed with central portions 31 which are widened out. The grooves 32 and recesses 33 can be formed for example by stamping into a plate of synethetic resin, as is known in the packing industry.

The final separation into individual elements is undertaken by the user. In this way also any other shapes of article, capable of being formed into a plate, can be produced. The surface does not need to be flat but could have a relief impressed into it simultaneously with the stamping of the recesses, for example one could form a recess to receive a spoon, a groove for a knife, and for a fork and so on.

Thus for example plate-shaped packs could be produced for holding eating implements for picnics.

The advantages of the invention are manifold. The plastics body according to the invention can be produced from a continuously extruded strip. The r separation of individual separable articles by means of channel-shaped grooves is easy to achieve by the use of simple equipment which can be modified at little cost. Accordingly, in comparison with the injection-moulding process, relatively small runs of a given article can be produced without making the individual component price unacceptably high as a result to high mould tooling costs, which can happen in the case of the manufacture by injection moulding. As the individual articles are separated from one another by grooves, waste is eliminated. Finally the plates are well suited to receiving printing. They can be stacked to form compact bundles.Individually they can be inserted into packs of sheet covering material without increasing their shipping volume, as was the case where ready moulded securing elements were employed. By the inclusion of one plate the pack is automatically provided with the required number of securing elements without this number having to be counted out each time. The body according to the invention can also, if necessary, be produced in rolled-up form, further multiplying the possibilities of use in packaging. The body can be rolled up and unrolled several times without tearing the webs that connect the individual articles.

Also according to the invention one can manufacture combined packs of articles. For example, on one and the same plate one could arrange strips for tunnel cloche supporting hoops according to Figure 3 and strips for sheet securing elements according to Figure 8 side by side.

The invention is not limited to the use of a particular plastics material, such as polypropylene which was selected for the embodiments described above. For example one could use any suitable plastics material which can be cold-formed at room temperature, such as for example the abovementioned polypropylene, but also low pressure polyethylene, a polyamide, or polyester or the like.

Claims (21)

1. A body of plastics material separable into individual articles comprising a plate of synthetic resin in which the individual articles are separated from one another by means of channel-shaped grooves which extend nearly through the thickness of the plate to leave only residual thin webs.

2. A body according to Claim 1 in which the webs are cut right through over part of their lengths.

3. A body according to Claim 1 or Claim 2 in which the strength of the webs is such that they can be manually broken by tearing or breaking, at least after an initial tear or cut.

4. A body according to any one of Claims 1 to 3 in which the plastics material is polypropylene, low pressure polyethylene, a polyamide or a polyester or the like.

5. A body according to any one of Claims 1 to 4 in which the grooves extends substantially parallel to one another.

6. A body according to any one of Claims 1 to 5 in which the articles are of elongated or strip-like shape.

7. A body according to Claim 6 in which the articles have pointed ends.

8. A body according to Claim 7 in which the plate is defined at two opposite ends by two mutually parallel edges interesecting the grooves at an acute angle.

9. A body according to Claim 7 in which the plate is defined at two opposite ends by saw tooth edges extending transversely with respect to the grooves.

10. A body according to Claim 1 in which the articles separated by the grooves are arranged directly adjacent one another.

11. A body according to Claim 1 in which the synthetic resin is a high polymer resin.

12. A process for manufacturing a body of plastics material which is separable into individual articles, comprising forming channel-shaped grooves in a plate of plastics material, the grooves penetrating nearly through the thickness of the plate to leave only a residual web and separating individual articles from one another.

13. A process according to Claim 12 in which the webs are cut right through over part of their lengths.

14. A process according to Claim 12 or Claim 13 in which a strip of thermoplastic synthetic resin material is continuously extruded to form a strip having the required thickness of the plate, provided with groovess extending parallel to the direction of extrusion, and cut up into individual plates by cuts transverse to the direction of the strip.

15. A package comprising a pre-determined number of consumer articles comprising the pack being in the form of a body of a plastics material separable into individual elongated consumer articles, in the form of a plate of plastics material in which the articles are separated from one another by channel-shaped grooves extending nearly through the thickness of the plate to leave only residual webs of a strength such that they can be manually broken or torn, at least after an initial tear or cut.

16. A pack according to Claim 15 comprising articles in the form of a pre-determined number of bendable hoops, with pointed ends, for supporting tunnel cloches.

17. A pack according to Claim 15 comprising articles in the form of a pre-determined number of bendable securing elements or pegs, capable of being inserted into the ground, for ground coveings, such as sheets, mats or nets.

18. A body of plastics material separable into individual articles, substantially as described with reference to Figures 1 and 2 of the accompanying drawings.

19. A body of plastics material separable into individual articles, substantially as described with reference to Figures 5 and 6 of the accompanying drawings.

20. A body of plastics material separable into individual articles, substantially as described with reference to Figures 5 and 6 as modified by Figure 9 of the accompanying drawings.

21. A method of manufacturing a body separable into individual articles, substantialily as described with reference to the accompanying drawings.