Bags

Abstract: The method of manufacturing a bag 10 comprises prov­ iding front and rear panels of material and providing straight end welds 14 that weld the panels together at suitably spaced locations, transversely to the direction of the bag. The mat­ erial is cut at an end cut 24 adjacent to each end weld, and is cut at a separating cut 26 which will form an open end for two bags between a pair of end welds and which extends gener­ ally transversely to the bag, the said separating cut 24 being so shaped that cut-outs 34 are formed in the said open ends to leave projecting tie parts 36 which in each bag are capable of being tied together to close the opening.

Description: The invention relates to a garbage bag as defined in the pre-characterizing part of claim 1. A garbage bag of this type has been known from CA-A-1 182 787. Garbage bags made of plastic are popular and are widely used especially for preparing kitchen refuse for collection by municipal garbage collectors. A problem that is often encountered with such bags is that it is often difficult to close them especially when substantially full. As a consequence there is usually some spillage. Furthermore dogs can become aware of the contents and will destroy the bags in an attempt to reach the contents. In an attempt to close these bags they are often tied at the corners which reduces the capacity of the bags. In the prior art bags according to CA-A-1 182 787, which can be formed as a continuous strip of tubular plastics material from which the bags can be separated along perforated tear lines, the open end of each bag has two projecting parts formed as rectangular triangles. By tying the two projecting parts together by hand the open end of the filled bag can be closed. Each triangular projecting tie part has a considerable height equal to half of its width, and thus the projections take a considerable percentage of the overall length of the bag. In the prior art such a length of the projections is found desirable for tying a second knot to form a carrying handle, but at the same time the projections reduce the capacity of the bag as compared with a rectangular bag having the same overall length. Therefore, there is a waste of plastic sheet material in that portion of the length of the bag which is formed by the projections. From US-A-4 345 712 there has been known a similar garbage bag having four projections capable of being tied together by hand, the projections being pointed projections connected by arc-like valleys. This form of the projections requires the bottom side of the bag to be formed with a correspondingly arcuate seam. This reduces the overall capacity of the bag, and the relation between the capacity of the bag and the amount of material is not improved over the aforementioned bag. From US-A-3 931 886 there has been known a bag for use as a nursing bottle liner having four projections of sinusoidal shape. This bag is neither intended nor suitable for use as a garbage bag, and the sinusoidal projections are not adapted for being tied together by hand for closing the open end of the bag. In fact, the open end of the bag is not to be closed, but to be folded over the rim of a nursing bottle. It is an object of the invention to provide a bag of the aforementioned kind which has a large usable capacity in relation to the overall length, whilst providing convenient means for tying the open end of the bag together. For solving this object the invention provides a garbage bag as defined in claim 1. It has been found that the provision of four projections of sinusoidal shape results in a substantial saving of plastics material, or a substantial improvement of the relation between the capacity of the bag and its overall length. The invention also relates to a plurality of such garbage bag forming a continuous strip of tubular plastics material as claimed in claim 3. An embodiment of the invention will now be described by way of example with reference to the accompanying drawings. In the drawings:- Figure 1 snows an extruded tube that has been laid flat immediately prior to separation of the bags, Figure 2 is a side view of two bags formed from the tube, Figure 3 is a perspective view from the side when filled but not yet closed, and Figure 4 is a front view of the bag when filled and closed. Referring now to Figure 1 there is shown an extruded tube 10 of plastics material which is arranged in lay-flat form i.e. with front and rear panels joined along their edges 12 (without any gussets being formed). The tube 10 is processed in welding and cutting apparatus (not shown) which provides the welds and cuts as will be described. A straight transverse end weld 14 (that welds the front and rear panels of the material together) is provided transversely to the direction of extrusion at suitably spaced locations 16 and 18. The end weld 14 comprises a pair of spaced parallel welds 20 and 22. A transverse end cut 24 is more between the two welds 20 and 22 to form the two bags. It will be seen that in the flat condition the bags comprise two rectangular panels joined at their edges 12 and at the end welds 14. The apparatus also makes a separating cut 26 which will form the open ends for each of the two bags that are formed between a pair of end cuts 24. The separating cut 26 is located midday between the end cuts 24 and is generally sinusoidal. Therefore in each of the bags 30 and 32 that are thus formed cut-outs 34 to leave projecting tie parts 36 in the other bag which tie parts 36 are capable of being tied together to close the opening as will be described. It will be seen that the two bags 30 and 32 have open ends which when the bags are in the lay-flat condition appear to be of different appearance. However once these ends are open, they will be of the same shape each with four cut-outs 34 and four projecting tie parts 36. When the bag 10 is filled with refuse (as shown in Figure 3), the diametrically opposite projecting tie parts 36 can be tied together to provide a substantially complete closure for the open end of the bag 10. (In Figure 4, there are shown openings 38 between the tie parts 36. This is for the purpose of clarity only and in fact these openings will be very small indeed.) It was found that this closure is more than adequate for the normal purposes to which the bag 10 is put in domestic circumstances. In this specification the term "cut" is used in a broad sense with the intention that it covers both a parting cut which parts one item from another and a perforation cut which provides a line of weakness that permits the items to be parted from one another conveniently by tearing or pulling. Thus the bags will either be provided as separate items or as separable parts of an elongated roll of material which can be parted therefrom either in a commercial outlet or in the home when required. It will be seen that by making the bags as described above a considerable amount of material is saved in addition to providing bags which are convenient to use for tying corners to close the open ends. This because with conventional bags only a portion can be filled if material is to be left to form ties. The upper limit of such filling is normally no bore than a position slightly lower than the valleys of the cut-outs 34. Furthermore, by having a straight end weld, the bag is capable of being filled to the maximum amount. Thus for forming bags 10 of the invention of the same practical capacity as conventional bags, up to 10% of the bagforming material may be saved. The invention is not limited to the precise constructional details hereinbefore described and illustrated. The bags may be gussetted if desired even though this will reduce the capacity of the bag as compared to that described above. However the provision of the straight closed end and the interleaved cut-outs and tie parts results in the bag having a larger capacity than the known bags mentioned above. The currently preferred plastics materials are high density or low density polyethylene or polypropylene. Other plastics materials are appreciated by those skilled in the art.

Claims: A garbage bag made of plastics sheet material for collecting kitchen garbage or the like, comprising in the lay-flat condition: front and rear panels joined to each other along three straight sides (12, 14) and having an open end (28) on the fourth side (26), the side (14) opposite the open end being formed by welding the panels together to form the bottom of the bag, and the fourth side (26) de-limiting the open end being shaped with projecting tie parts (36) capable of being tied together by hand to close the open end, characterized in that in the open condition of the bag the fourth side (26) is of generally sinusoidal shape and has four projecting tie parts (36). A garbage bag as claimed in claim 1, wherein the bag is a gusseted bag. A plurality of garbage bags as claimed in claim 1 forming a continuous strip (10) of tubular plastics material having, at spaced intervals, pairs of parallel transverse welds (20,22) forming the bottoms of two adjoining bags and a transverse perforated tear line (24) between said welds (20,22) for separating two adjoining bags at their bottoms, and having at locations intermediate said pairs of welds (20,22) transverse perforated tear lines (26) of general sinusoidal shape for separating two adjoining bags (30,32) at their open ends, said sinusoidal tear line (26) defining four projections at the open ends of the two adjoining bags (30,32).

Inventors: GREYVENSTEIN LOURENCE CORNELIU, GREYVENSTEIN, LOURENCE CORNELIUS JOHANNES
Applicants: GARFUSE BV, PATHOLD INVESTMENTS CO, GARFUSE B.V., PATHOLD INVESTMENTS COMPANY LIMITED
Application year: 1987
Main classification: B65D33
IPC codes: B65D33