Improved non-shrinkable carrier

Abstract: A carrier for use as a stiffening member, e.g. in polymeric extrusions used in the motor and building industries, being of elongate strip form and having a plurality of longitudinally spaced, transversely extending members (1) therein, wherein the said members are maintained in their spaced relationship by means of at least one sinuous or zig-zag securing member (4) running longitudinally of the carrier and being welded or otherwise rigidly secured to each transversely extending member. The or each securing member (4) may be wire having a generally uniform zig-zag construction, wherein a substantial part of a corrugation or zig-zag thereof is located between adjacent transversely extending members (1), or may be wire of a more extended sinuous construction such that its transverse positioning within the carrier is varied along the length of the carrier.

Description: This invention relates to carriers which are used, inter alia, as a reinforcement in rubber and plastics extrusions used in the motor and building industries, and also as a support frame for elongate textile material edge trims in the motor industry. Typical examples of wire carriers can be seen in patent specifications nos. US-A-3949530, US-A-3685231, GB-A-1545511, US-A-3239987, US-A-3198689, GB-A-1467412 and US-A-3430387. This invention is, however, applicable to other types of carrier, e.g. of stamped or slotted metal or other semi-rigid resilient sheet material. Most, if not all, known wire carriers comprise a continuous length of stiff metal wire bent to and fro into a generally zig-zag configuration, with looped wire edge regions and transverse lengths of wire in the central region of the carrier joining the looped edge regions. The transverse lengths of wire may be straight or curved and may define straight sided, banana-shaped or propeller-shaped regions therebetween or any combination thereof. The generally zig-zag wire is normally retained in its configuration by a plurality of strands of material extending longitudinally with respect to the carrier, parallel to its edges, and connected to each transverse length of wire and/or the looped edge regions by knitting thereof into the generally zig-zag wire so as to provide a stitch or knot at each crossing point. The end product is known as a knitted wire carrier and is clearly illustrated in GB-A-1407412 and US-A-3198689. The longitudinal strands help to reduce the stretching and shrinkage of the product in which the carrier is comprised. The aforesaid knitted wire carriers have lengthwise strands formed of textile material, such as polyester, cotton or the like, or even light wire, and have been used for many years in the manufacture of, inter alia, edge trim or combination edge trim/door, or boot, seals for motor vehicles. More recently, carriers of the slotted or stamped metal type have also been used in the manufacture of such edge trim/seals. The edge trims are normally formed by extruding a polymeric material onto the carrier, by passing it through an extruder, then conforming the resultant product to a generally U-shaped cross-section, by passing it through a forming die. Alternatively, in some instances, the carrier may be pre-formed into a U-shape, then passed through an extruder with a U-shaped die. Passing the carrier through the extrusion and/or forming dies normally involves its being dragged or pulled through the dies from its forward end, and this results in the carrier being stretched as it is passed through the dies. This presents a problem in that the resulting product has a tendency to shrink, which, particularly if it occurs after installation on, for example, a motor vehicle door flange, causes great inconvenience and may necessitate replacement and in any case involves the trim being cut oversized to account for shrinkage between cutting and installation. The problems of stretching and shrinkage are particularly acute with carriers of the knitted wire type, or the slotted metal type wherein adjacent slots overlap to some extent, but exist nevertheless in all types. It has been proposed to alleviate the problems associated with stretching and shrinkage of the carrier by providing a continuous straight length of stiff metal wire running parallel to the edges of the carrier and welded to each of the transverse lengths of wire and/or metal slats in the central region of the carrier. Whilst reducing the problems associated with shrinkage of the end product, the wire substantially reduces the flexibility thereof. If more than one wire is provided along the length of the carrier, the possibility of any lateral flexing of the carrier is completely eliminated. Although the whole purpose of knitted wire or other carriers in extruded edge trims is to stiffen the polymeric material of the extrusion, in order for it better to grip, for example, a motor vehicle door flange, there is nevertheless a requirement for local flexibility so that the trim can negotiate various bends in the flange satisfactorily. It is an object of the present invention to provide a carrier for incorporation into an edge trim which substantially overcomes the problems of stretching and shrinkage, yet still provides for flexibility of the resulting product. With the ever increasing complexity in motor vehicle manufacture, and in particular, the ever increasing customer requirement for efficient, good looking door seals in motor vehicles, it is important the door seals fit correctly and do not fall off or become displaced. If they do become displaced even by a small amount, they will look unsightly, will affect door shut pressures, and will also not form a satisfactory air/water seal between the door and door opening. Modern motor vehicles tend to be manufactured with a distinct waistline half way up the body, at approximately door lock height, and this results in two changes of direction in the flange to which the edge trim/door seal is to be fitted. Furthermore, with the advent of small motor vehicles, the sealing strip is required to negotiate sharp inside and outside bends, as well as lateral bends at the waistline, and yet still maintain its correct location on the flange, in spite of regular opening and shutting of the door. It must also be borne in mind that when the edge trim is bent, especially if it has a door seal attached or integral therewith, then the polymeric material may deform, or wrinkle or buckle, as a result of stretching, twisting or compression, thus resulting in an ugly appearance. To a large extent, these deficiencies can be minimised or avoided by designing the stiffness of the knitted wire carrier accordingly, e.g. by making selected regions of the carrier stiffer than others, either along the length of the carrier, or across its width. Various attempts to vary the stiffness of wire carriers have been proposed, and these proposals have met with different levels of success. For example, in EP-B-0155811, a knitted wire carrier is disclosed wherein at least two different zig-zag wires are incorporated in the carrier. In another construction disclosed in EP-B-0045176, two different types of textile material are used for the knitted longitudinal strands, one of the materials being degradable so that when a controlled amount of heat, or radiation, or other means is applied to the edge trim or the like in which the knitted carrier is located, the one material can be degraded so that it will no longer inhibit relative movement of the transverse lengths of wire in the carrier, and will thus cause a change in the stiffness of that region of the carrier. In DE-A-3129803 various constructions of carrier which may be used in polymeric extrusions for the motor and building industry are disclosed. In all these constructions the carrier is of elongate strip form and has a plurality of longitudinally spaced transversely extending members therein and the members are maintained in their spaced relationship by means of at least one sinuous securing member running longitudinally of the carrier. The sinuous securing member(s) is secured to the transversely extending member(s) by selected weld points. A similar construction of carrier is disclosed in GB-A-2022180 although in this disclosure it is not clear how the crinkled or corrugated longitudinally extending securing members are bonded to the transversely extending members. In the above specifications various attempts have been made to vary the stiffness of the carrier. However, in none of the constructions disclosed is it possible to vary stiffness or flexibility of the carrier across its width because throughout its length the carrier is formed of uniform construction so as to overcome the problems with stretching and shrinkage as previously discussed. It is another object of the present invention to provide a carrier for incorporation into an edge trim which substantially overcomes the problems of stretching and shrinkage, yet provides for varying stiffness and flexibility along the length and across the width of the carrier. According to the present invention there is provided a carrier for use as a stiffening member, e.g. in polymeric extrusions used in the motor and building industries, said carrier being of elongate strip form and having a plurality of longitudinally spaced, transversely extending members therein, the said members being maintained in their spaced relationship by means of at least one sinuous securing member running longitudinally of the carrier, said sinuous securing member being welded or otherwise rigidly secured to each transversely extending member, characterised in that the transverse location of the or each sinuous member is varied along the length of the carrier. Preferably there are included a plurality of such sinuous securing members. The or each securing member is preferably wire having a generally uniform crinkled or corrugated construction, and at least a substantial part of a corrugation or crinkle thereof is located between adjacent transversely extending members. It will, of course, be understood that the term "wire" embraces metal wire, polymeric wire or other semi-rigid resilient wire, and that the term "weld" includes within its scope arc-welding or heat welding or other means of fusion, e.g. adhesives. Use of the crinkled or corrugated rather than a non-corrugated securing member ensures that flexibility of the carrier is maintained, whilst its ability to stretch is reduced. This is particularly advantageous if a plurality of such securing members is provided, since lateral flexing of the carrier still remains possible. Variation of the transverse location of the securing member provides for variations in the character of the local flexibility of the carrier. In one embodiment of the invention, the transversely extending members are formed from a length of wire bent to and fro to form a zig-zag construction, the alternate ends of adjacent transversely extending members being connected by U-shaped loop portions defining the opposite edges of the carrier, and into which is knitted at least one warp strand. The said at least one warp strand may be degradable by heat or chemical, mechanical or other means and may be so degraded after the edge trim is formed. Alternatively, the transversely extending members may consist of sheet metal, or other semi-rigid resilient sheet material, as, for example, in a slotted or stamped metal carrier. The present invention is now described by way of example with reference to the accompanying schematic drawings, in which: FIGURE 1 shows a carrier according to the first aspect of the present invention; FIGURE 2 shows to an enlarged scale part of a flange having a free edge (F) with which the carrier of Figure 1 is intended to co-operate; FIGURES 3-5 show other embodiments of carriers according to the first aspect of the present invention; FIGURES 6, 7 & 8 are schematic representations of a carrier according to the present invention, when flexed; FIGURE 9 shows a wire carrier according to the second aspect of the present invention; and FIGURE 10 shows a slotted or stamped metal carrier according to the second aspect of the present invention. Briefly, Figures 1 and 3-5 all show carriers comprising a length of stiff wire 3 bent to and fro to form a zig-zag construction, thereby forming a plurality of transversely extending members 1, alternate ends of adjacent of which are connected by U-shaped loop portions 2 defining the opposite edges of the carrier. The transverse members 1 are maintained in their spaced relationship by a plurality of warp strands of textile or other material running longitudinally of the carrier and connected by knitting or stitching to each member 1 in known manner and by means of at least one sinuous, e.g. crinkled or corrugated, securing member 4 which, or each of which, is rigidly secured to each transversely extending member 1, e.g. by welding. The carrier of Figure 1 includes two sinuous securing members 4 and comprises three distinct longitudinal zones A', X, A''. In zones A' and A'', the securing members are disposed towards opposite edge regions of the carrier. When the carrier is deformed into its final U-shape and incorporated in an edge trim, the spine region of the resulting edge trim is longitudinally extendable which makes it suitable for installation on an outer circumference of a flange, as illustrated in regions A' and A" in Figure 2. In zone X of the carrier of Figure 1, the securing members 4 are disposed in the central region of the carrier, which results in the edge regions of the final edge trim being extendable, and in this zone are particularly suited for installation on an inner circumference of a flange, as illustrated in region X of Figure 2. The carrier of Figure 3 is similar to that of Figure 1 except that in zone X, only one of the sinuous securing members 4 is disposed in the central region of the carrier. This zone of the carrier is particularly suited to traversing a lateral bend in a flange, since only one edge of the resulting edge trim will be extendable. The carriers of Figures 4 and 5 are similar in function to that of Figure 3 except that they include one sinuous securing member 4 and one straight welded wire 5. In Figure 5 the sinuous securing member 4 includes a straight middle zone 7. Figures 6-8 simply serve to illustrate the flexibility of the carriers according to the present invention, with Figure 7 showing lateral flexing and Figure 8 showing dorsal/ventral flexing. The transversely extending members 1 may be of square cross-section, but they may also be of circular, rectangular triangular or other cross-section. The carrier of Figure 9 is constructed from a length of stiff wire 3 bent to and fro to form a zig-zag configuration, thereby forming a plurality of transversely extending members 1, alternate ends of adjacent of which are connected by U-shaped loop portions 2 defining the opposite edges of the carrier. The transverse members 1 are maintained in their spaced relationship by the traditional longitudinally extending warps connected by knitting or stitching to the members 1 and by a sinuous securing member 40 which in this embodiment is of a non-crinkled or non-corrugated form, but whose transverse location within the carrier varies along its length. The carrier of Figure 10 is constructed of stamped or slotted metal or other sheet material 6 with overlapping slits or slots 8 defining transverse members 11. In a similar manner to the embodiment of Figure 9, two non-crinkled or non-corrugated securing members 40, e.g. of wire, are welded to the slotted metal's transverse members 11 to vary the stiffness of the carrier along its length. It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention as defined by the accompanying claims. For example, the members 40 in the embodiment of Figure 10 could be crinkled.

Claims: A carrier for use as a stiffening member, e.g. in polymeric extrusions used in the motor and building industries, said carrier being of elongate strip form and having a plurality of longitudinally spaced, transversely extending members (1) therein, the said members (1) being maintained in their spaced relationship by means of at least one sinuous securing member (4 or 40) running longitudinally of the carrier, said sinuous securing member (4 or 40) being welded or otherwise rigidly secured to each transversely extending member (1), characterised in that the transverse location of the or each sinuous member (4 or 40) is varied along the length of the carrier. A carrier according to claim 1 and including a plurality of said sinuous securing members (4 or 40). A carrier according to claim 1 or 2 wherein the or each sinuous securing member (4 or 40) is wire having a generally uniform crinkled or corrugated construction, and wherein at least part of a corrugation or crinkle of the or each sinuous securing member (4 or 40) is located between each of said transversely extending members (1). A carrier according to claim 1 or 2 wherein the or each securing member (4 or 40) is wire having a generally uniform crinkled or corrugated construction and wherein at least part of a corrugation or crinkle of the or each securing member (4 or 40) is located between at least two of the transversely extending members (1). A carrier according to any one of claims 1-4 wherein the or each sinuous securing member is formed of wire, a part of which is crinkled or corrugated and part of which is not crinkled or corrugated. A carrier according to any one of claims 1-5 wherein the transverse members are part of a knitted wire carrier made up of a length of wire bent to and fro into a zig-zag construction to provide said transverse members (1), the alternate ends of which are connected to their adjacent transverse members by U-shaped loop portions (2) defining the opposite edges of the carrier, and into which one or more warp strands are knitted. A carrier (6) according to any one of claims 1-5 which is formed of stamped or slotted metal.

Inventors: COOK JOHN EDWARD, MATSUMIYA JAMES A, COOK, JOHN EDWARD, MATSUMIYA, JAMES A.
Applicants: SCHLEGEL UK HOLDINGS, SCHLEGEL (UK) HOLDINGS LIMITED
Application year: 1990
Main classification: B60R13
IPC codes: B29K105, B60J10, B29B15, B29C45, B29L31, B29C47