SECURING PLASTICS ARTICLES

Abstract: A method of securing a rigid plastics member (5) to a sheet of flexible plastics material (2) comprises moulding the rigid plastics member with upstanding cylindrical studs (6), pressing the sheet material (2) against the studs (6) whilst the sheet material is at an elevated temperature to form apertures in the sheet material in which the studs are received; and subsequently flattening the studs to form an enlarged head (7) which fixes the sheet material in position. Typical uses of the invention include the production of garment hangers (as illustrated) and carrier bags.

Description: SECURING PLASTICS ARTICLES This invention relates to a method of securing a rigid plastics article to a sheet of material, and in the preferred embodiment the invention provides a method of securing a rigid plastics article to a sheet of plastics material in order to form a composite plastics article. It is known to secure a rigid plastics handle to a sheet plastics bag by means of a heat welding process to form a carrier bag. This process has a number of disadvantages however, including in particular that the process is slow and thus production costs are relatively high and that the materials of the handle and bag must be compatible if a satisfactory weld is to be obtained. Further, this process is not suitable for the production of small items such as garment hanging devices comprising a rigid hook and a sheet of plastics material. The preferred embodiment of the invention provides a method of securing a rigid plastics member to a sheet of material which produces a joint having a strength at least comparable with that produced by heat welding yet which is quicker to carry out, can be used to join materials which could not be joined by heat welding, and which can be applied to small items to provide for example, a small garment hanger having a rigid hook. According to one aspect of the present invention there is provided a method of securing a rigid plastics member to a sheet of material, the method comprising: providing on the plastics member at least one stud up¬ standing from a surface of the member; passing the free end of the stud through an aperture in the sheet; heating the free end of the stud; and deforming the free end of the stud to form an enlarged head at the free end of the stud and a neck between the head and the said surface, the neck being received in the aperture and the sheet of material being trapped between the said surface and the head. The plastics member must, of course, be sufficiently rigid to provide the or each stud and a base upon which the or each stud is located. However, it will be appreciated that the plastics member need not be absolutely rigid, and indeed in many applications of the invention the plastics member will be readily bendable by hand. Thus, the term "rigid" as used herein is to be construed broadly as covering all plastics members which are sufficiently rigid to enable them to be used in the method of the invention. Preferably the plastics member is initially integrally formed with a number of studs appropriate to the article being produced and, during assembly of the article, the studs are passed through complementary apertures in a flexible pl-astics sheet and are then flattened by a heated tool to rivet the plastics member to the plastics sheet. By using this technique to join the plastics member to the sheet a strong mechanical interlocking of the sheet and plastics member is achieved. Such a mechanical interlocking obviates the need to form a bond or weld between the sheet and the plastics and has been found to be both strong and reliable in use. Further, although in the preferred embodiment the sheet and plastics member are both formed of polypropylene, the fact that the sheet and plastics member are joined by a mechanical interlock means that the sheet and plastics member could be of different materials not readily joined by welding techniques. In the preferred embodiment the sheet is of a flexible thermoplastic material and the apertures in the sheet are formed by pressing the sheet against the studs and heating the sheet so that it softens and enables the studs to penetrate, thereby forming the apertures as the studs pass through them. The studs are then flattened to a mushroom shape, i.e. are flattened in a manner which produces an enlargement at the free end of the stud and a neck adjacent the base of the stud, the neck being located in the aperture. In an embodiment of the invention for use as a garment hanger the flexible sheet carries point of sale information relating to the product and is secured to the product by means of at least one double ended toggle which is stitched through the sheet and the items lying there¬ between. Of course, other means of securing the sheet material to the item, e.g. adhesive or conventional stitching, may be used. In an embodiment of the invention for use as a carrier bag the flexible sheet carries advertising material in the conventional manner. The invention will be better understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawing wherein: Figure 1 is a plan view of an article made by means of a preferred embodiment of the invention; Figure 2 shows a hook for use in the article of Figure 1 ; and Figure 3 is a side view of the article of Figure 1 folded into its use configuration. Referring firstly to Figure 1 there is shown a display hanger 1 comprises a sheet 2 of flexible poly- propylene material on which is printed suitable point- of-sale information 3« The sheet 2 includes a space 4 for the Trade Mark of the seller of the item displayed. Secured to the sheet 2 is .a substantially rigid hook 5 also of polypropylene. The hook 5 may typically be approximately 1mm thick and lies flat against the sheet 2 when the hanger 1 is in the configuration shown in Figure 1. Each hook 5 is moulded with a pair of up- standing substantially cylindrical studs 6 (Figure 2) which may, as moulded, be approximately 3mm high. Each hook 5 is secured to its associated sheet 2 holding the studs 6 against the sheet 2 and heating the sheet to soften it thereby enabling the studs to penetrate the sheet material and form apertures in which the studs are received. The studs 6 are then flattened by means of a heated tool to rivet the hook onto the sheet. Flattening of the studs produces an enlarged head 7 at the free end of each stud, whilst the base of each stud remains at substantially its original diameter. Thus, the deformed stud is of "mushroom" shape with the neck region formed by the base of the stud received within the aperture of the flexible sheet. The mechanical interlock between the hook and the sheet formed by the riveting process has been found to provide a strong and reliable connection between the hook and the sheet and in particular has been found t ' o be at least comparable in strength in use to the joints commonly produced by heat sealing a rigid member to flexible sheet material. It will be appreciated that although in the preferred embodiment both hook and sheet are of the same plastics material, the riveting technique enables the sheet to be of a material which would be difficult or impossible to join to the hook by conventional bonding or • welding techniques. To use the hanger 1, the flexible sheet 2 is folded so that the hanger adopts the shape shown in Figure 3 ^ The articles to be displayed, e.g. two pairs of socks, are inserted between the depending arms 9 of flexible material and secured in position, e.g. by means of a double ended toggle stitched through the arms 9 and the articles therebetween. The articles can then be dis¬ played by hanging the hook 5 on a suitable rail, bar or hook. It should be noted that if the apertures are formed by the preferred method described above it is not essential that the material of the sheet is broken during the penetration of the sheet by the studs, or subsequently during flattening of the studs. Instead, the softened material of the sheet may simply stretch over the stud, and provided that the aperture which receives the base of the stud is well defined and is smaller in size than the mushroom head of the stud on adequate mechanical interlock will be formed. It will be appreciated that many changes may be made within the scope of the invention. For example, the apertures for the studs may be formed otherwise than as described above, the materials used may vary according to intended use, and the dimensions of the various com- ponents may be varied to suit the materials used and • intended use of the product. For example, if the inven¬ tion is used to produce a carrier bag the plastics member will include a handle part and a bar having sufficient' studs to effect an adequate interlock with the sheet material.

Claims: CLAIMS : 1. A method of securing a rigid plastics member to a sheet of material, the method comprising: providing on the plastics member at least one stud upstanding from a surface of the member; passing the free end of the stud through an aperture in the sheet; heating the free end of the stud; and deforming the free end of the stud to form an enlarged head at the free end of the stud and a neck between the head and the said surface, the neck being received in the aperture and the sheet of material being trapped between the said surface and the head. 2. A method according to claim 1 wherein the sheet of material is a sheet of plastics material. 3* A method according to claim 2 wherein the plastics material is a thermoplasticmaterial and the or each aperture is formed by pressing the sheet material against the plastics member whilst the sheet material is at an elevated temperature whereby the or each stud may penetrate the sheet material to form the or each aperture. 4- A method according to any preceding claim wherein the plastics member is a hook and the sheet material is suitable for securing to a garment. 5- A method according to any of claims 1 to 3 wherein the plastics member is a handle and the sheet material forms a bag. 6. A method according to any preceding claim wherein the plastics member is an integral plastics moulding. 7 • A method according to any preceding claim wherein the plastics member is of polypropylene. 8. A method according to any preceding claim wherein the sheet of material is of the same material as the rigid plastics member. 9« A method of securing a rigid plastics member to a sheet of material substantially as herein described.

Inventors: FROST GEOFFREY REGINALD, FROST, GEOFFREY, REGINALD
Applicants: ROBINSON & SONS LTD, ROBINSON & SONS LIMITED
Application year: 1985
Main classification: B29C65
IPC codes: B29C65, B65D73