GB2178468A

GB2178468A - Sealing strip

Info

Publication number: GB2178468A
Application number: GB08617382A
Authority: GB
Inventors: Peter Titz
Original assignee: Draftex Industries Ltd
Current assignee: Laird Holdings Ltd
Priority date: 1985-07-27
Filing date: 1986-07-16
Publication date: 1987-02-11
Also published as: FR2585436A3; GB8617382D0; DE8619573U1; GB8519015D0; FR2585436B3

Abstract

A channel-shaped sealing strip comprises channel-form metal carrier 5 embedded in extruded plastics or rubber material 6, and welded to it a flexible substantially inextensible metal foil 26 which substantially prevents stretching of the strip. <IMAGE>

Description

SPECIFICATION Channel-shaped strip structures and reinforcements therefor The invention relates to channel-shaped strip structures and reinforcements therefor, and more specifically, though not exclusively, to reinforcements for channel-shaped strips such as for sealing, finishing, and guiding purposes, and to such strip structures and channel-shaped strips. Such strips may, for example, be used for finishing or sealing the flanges around openings in vehicle bodies or the like, or for supporting, sealing or guiding the edges of window glass.

According to the invention, there is provided a reinforcement for a strip structure, comprising a carrier made of elements extending side-by-side across the width of the carrier and at least one flexible substantially inextensible member made of metal foil and running along the length of the structure and secured to the elements by welding so as to resist any tendency of the carrier to stretch.

According to the invention, there is also provided a channel-shaped strip structure, comprising a channelshaped carrier made of side-by-side arranged U-form elements and at least partially embedded in flexible covering material, and at least one flexible substantially inextensible member made of metal foil running along the length of the strip, welded to at least some of the elements, and covered by the flexible material, so as to resist any tendency of the structure to stretch.

Carriers embodying the invention for reinforcing strip structures, and channel-shaped strip structures embodying the invention, will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a plan view of one of the carriers at an early stage in manufacture of the strip; Figure 2 is a cross-section on the line ll-ll of Figure 1: Figure 3 is a view corresponding to Figure 1 but showing a different one of the carriers; Figure 4 is a cross-section through the carrier of Figure 1 but showing the carrier after an extrusion process has been carried out; Figure 5 is a perspective view of a strip produced from the structure shown in Figure 4; and Figure 6 is a cross-section through a modified form of the strip shown in Figure 5.

The channel-shaped strip structures to be more specifically described have, in their finished form, a metal carrier 5 embedded in plastics or rubber or similar covering material 6. As shown in Figures 4, 5 and 6, the covering material 6 on the inside of the channel is arranged to define gripping lips 1 OA,1 OB,1OC and 12 which run along the facing side walls of the channel. In use, the strip may be placed over a flange running around the opening in a vehicle body, such as a door opening for example, and, when in such position, provides weather and draught-proofing as well as covering and protecting the edge of the flange.

In addition, the sealing strip may support a longitudinal sealing section 14, see Figure 6, preferably of soft material such as sponge rubber, against which a door (for closing the opening) shuts, and this sealing section provides further draught-proofing and a weather seal. As shown in Figure 6, the sealing section 14 is adhesively attached to the outside of the channel-shaped material 6. instead, however, it may be integrally extruded therewith.

The gripping lips 1 OA,10B,10C and 12 help to prevent inadvertent removal of the strip from the flange (e.g. flange 15, see Figure 6) and also improve the weather sealing properties of the strip. The number of gripping lips on each side of the channel may be varied.

The metal carrier 5 supports the covering material 6 and gives strength and resilience to the finished sealing strip so as to ensure that it has a firm grip on the flange. At the same time, however, the carrier must be sufficientiy flexible to enable the strip to be relatively easily bent in all directions about its longitudinal axis so as to follow curves in the flange to which it is to be fitted.

In use, the strip may be supplied to the vehicle body manufacturer already cut into lengths suited to particular door openings. Such lengths may be joined on themselves to provide a completely closed loop. In such cases, it will be appreciated that it is very important that the sealing strip should maintain a substantially constant length once its manufacturing process has been completed. If it undergoes changes in length, then it may be found to be of incorrect length when it comes to be fitted to the vehicle body.

If it changes its length after having been fitted to the vehicle body, for example if it shrinks, it will tend to be pulled off the flange at corners or bends in the flange and thus provide an unsightly appearance and ineffective weather seal. Various factors can tend to change the length of the sealing strip. For example, the strip may be subjected to tension while it is being fitted to the flange. It will also be subjected to tension during its manufacturing process, and if this causes stretching, then it may shrink by subsequently resiling.

Temperature changes may also tend to change its length. Such temperature changes may merely be ambient temperature changes. In addition, however, the sealing strip may be subjected to quite substantial changes in temperature in the case where the vehicle body to which it is fitted is passed through a paint-drying oven.

It is in fact particularly important that changes in length due to stretching are prevented. It may be advantageous for the strip to be slightly compressible lengthwise. This enables the length of the finished strip to be adjusted slightly to take account of tolerances in the length of the flange to which it is fitted.

Figure 1 shows one form which the metal carrier 5 may take at an early stage in the manufacturing process. The carrier is formed out of longitudinal strip metal. At the stage shown in Figure 1, the strip metal has been formed so as to provide a plurality of side-by-side elements 18 extending across the width of the blank which are connected together by short integral connecting links 20 which are inclined with respect to the elements 18. Such a structure may be manufactured by any convenient way, such as by cutting slots through the blank by means of a suitable punch. Instead, and preferably, however, slits can be cut at appropriate places through the blank and the slits then converted into slots by longitudinally stretching the blank - as by rolling it along narrow marginal regions 22,24 so as to thin it down along these regions and thus to increase its length.

Figure 3 shows another form which the carrier can take (at an early stage in its manufacture). In this case, it comprises elements 18 joined by integral, straight, connecting links 20.

In addition, and in accordance with a feature of the invention, the structures of Figures 1 and 3 have associated with them respective flexible substantially inextensible members 26 each in the form of metal foil about 0.5 millimetres thick. The foil is welded, preferably by laser welding, to the carrier elements 18.

Figure 2 illustrates the welding in more detail and to an enlarged scale. As shown, the foil 26 is welded to the carrier elements 18 by laser-welded spot welds 27.

These spot welds 27 are small compared to the width of each carrier element 18, that is, compared with its dimension along the length of the carrier. It is important and significant that the welds 27 should be small compared with the widths of the carrier elements because this maintains maximum flexibility of the foil.

Its flexibility is removed at the points where it is actually welded to the carrier elements and it is therefore desirable, for maximum flexibility that these points should be as small as possible. It will also be noted that the foil 26 is not welded to the connecting elements 20. If it were so welded this would reduce the foil's flexibility.

In the case of the carrier shown in Figure 3, this also would have spot welds small in relation to the widths of the carrier elements 18.

The next stage in the manufacturing process com prises the feeding of the carrier 5(usually in its flat form shown in Figures 1 and 3), together with the foil 26 thereon, into an extruder which applies a coating of the covering material 6. After emerging from the extruder, the structure has the form shown in Figure 4 (this Figure in fact refers to the structure of Figure 1 but at the same stage in the manufacturing process, the structure of Figure 3 would have a corresponding shape). The covering material 6 thus covers the metal carrier 5 and the foil 26 and defines the gripping lips 1 OA,1 OB,10C and 12.

After (or perhaps before) the extrusion process, the structure is bent into channel form as shown in Figure 5 (for the carrier of the type shown in Figure 1); in Figure 5, part of the covering material 6 is broken away to show the carrier 5 and the foil 26.

in the case of the carrier of the form shown in Figure 1, the marginal regions 22,24 can be broken as shown in Figure 5 but the links 20 remain integral; the breaking process can be carried out before or after the extrusion process and may be carried out before or after the extrusion process and may be carried out before or after the foil 26 is welded in position. In the case of the carrier of the form shown in Figure 3, however, the links 20 may be arranged to break; in this case, the breaking process is carried out after the foil 26 is welded in position (and before or after the extrusion process).The structure shown in Figures 1 and 5 has the advantage that the marginal regions 22,24 provide added strength for the carrier to withstand tension forces which may be applied to it during manufacture, but are afterwards fractured, as described, so as not to impede the flexibility of the carrier in the finished sealing strip and so as to allow some lengthwise compressibility.

In the finished sealing strip, the foil 26 provides very good resistance to tensile forces. Tension applied to the strip is applied to, and therefore resisted by, the substantially inextensible foil, but of course the foil does not impede the flexibility of the finished sealing strip. Furthermore, because the foil is very thin and flexible, it does not impede the slight lengthwise compressibility of the strip.

As stated above, the foil 26 is attached to the carrier by welding to the carrier elements 18. It is not necessary for the foil to be welded to every carrier element 18: the compressibility of the strip may be increased by decreasing, preferably in regular fashion along the length of the carrier, the number of elements to which the foil is welded.

The position, with respect to the longitudinal axis of symmetry of the carrier, of the foil 26 may be varied. It may be advantageous, as shown in Figure 1, to arrange for the foil to run along the length of the strip at a position off its axis of symmetry. In this position, the foil helps to control the neutral axis of bending when the finished strip is curved to fit on to the mounting flange.

There may be more than one foil attached to the carrier.

Although the foregoing description is with reference to the use of strips for fitting on to flanges and the like, the strips may instead be used as window glass guiding channels. Again, the foil 26 helps to resist tension forces. In such application, the lips 10A,10B,10C and 1 2 may be removed or modified so as to facilitate entry of the window glass.

Claims

1. A reinforcement for a strip structure, comprising a carrier made of elements extending side-by-side across the width of the carrier and at least one flexible substantially inextensible member made of metal foil and running along the length of the structure and secured to at least some of the elements by welding so as to resist any tendency of the carrier to stretch.

2. A reinforcement according to claim 1, in which the elements and the member are embedded in flexible covering material.

3. A reinforcement according to claim 1 or 2, of channel-shaped form.

4. A channel-shaped strip structure, comprising a channel-shaped carrier made of side-by-side arranged U-form elements and at least partially embedded in flexible covering material, and at least one flexible substantially inextensible member made of metal foil running along the length of the strip, welded to at least some of the elements, and covered by the flexible material, so as to resist any tendency of the structure to stretch.

5. A structure according to claim 4, in which the covering material is extruded material.

6. A structure according to claim 5, in which the extruded material defines gripping lips extending along the length of the structure along opposite inside facing side walls.

7. A structure according to any one of claims 4 to 6, in which the elements of the carrier are connected together by integral flexible connecting links.

8. A reinforcement or structure according to any preceding claim, in which the foil is welded to the elements by means of respective spot welds each having a dimension along the length of the carrier which is small compared with the dimension of the respective element in the same direction.

9. A reinforcement or structure according to any preceding claim, in which the welding is laser welding.

10. A reinforcement for a strip structure, substantially as described with reference to Figures 1 and 2 of the accompanying drawings.

11. A reinforcement for a strip structure, substantially as described with reference to Figure 3 of the accompanying drawings.

12. A reinforcement for a strip structure, substantially as described with reference to Figure 4 of the accompanying drawings.

13. A channel-shaped strip structure, substantially as described with reference to Figure 5 of the accompanying drawings.

14. A channel-shaped strip structure, substantially as described with reference to Figure 6 of the accompanying drawings.