Patent Publication Number: US-2004056433-A1

Title: Sealing, trimming and finishing strips

Description:
BACKGROUND OF THE INVENTION  
       [0001] The invention relates to a sealing, trimming or finishing strip, comprising a longitudinally extending channel-shaped gripping part for embracingly gripping a mount, at least one inside side wall of the channel supporting a gripping element in the form of a relatively thin web of flexible material extending inwardly of the channel from an integral junction with the side wall and also extending along the length of the strip, the web having a thickness which increases progressively in the direction away from the side wall to form at its distal edge a foot of enlarged cross-section compared with the web.  
       DESCRIPTION OF RELATED ART  
       [0002] Such a strip is shown, for example, in DE-A-3 239 752. Here, the foot is offset in relation to the web. Resistance against removal of the gripping part from the mount is primarily produced by a wedging action between the gripping element and the gripping part.  
       [0003] Another such strip is shown in U.S. Pat. No. 4,695,499. In this case, resistance against removal of the gripping part from the mount is produced by wedging of the foot between the mount and a separate stop member extending from the inside side wall of the channel adjacent the web.  
       SUMMARY OF THE INVENTION  
       [0004] According to the invention, the sealing, trimming or finishing strip as first set forth above is characterised in that characterised in that the foot has two integral foot portions which define respective distal surface portions integrally forming a distal foot surface, the two foot portions being positioned on opposite sides of a plane which is substantially perpendicular to the foot surface and extends through and parallel to the length of the web, the foot surface being resiliently forced into frictional area contact with the mount when the gripping part embraces the mount with the web extending tranverse to the mount, the web being pivotal at its junction with the side wall of the channel such that any tendency of movement of one of the surface portions away from the mount urges the other surface portion thereof into firmer frictional contact with the mount to resist removal of the gripping part from the mount. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0005] Sealing, trimming and finishing strips embodying the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:  
     [0006]FIG. 1 is a cross-section through one of the strips, prior to its engagement with the flange around an opening in a vehicle body;  
     [0007]FIG. 2 is a cross-section of the strip shown in FIG. 1 but in engagement with the flange;  
     [0008]FIG. 3 is a cross-section of the strip of FIG. 1 but in an alternative configuration;  
     [0009]FIG. 4 is a cross-section of another one of the strips, prior to its engagement with the flange;  
     [0010]FIG. 5 is a cross-section of the strip shown in FIG. 4 but in engagement with the flange;  
     [0011]FIG. 6 is a cross-section of the strip shown in FIG. 4 but in a different configuration; and  
     [0012]FIGS. 7 a  to  7   j  show cross-sections through different forms of gripping element used in the strips embodying the invention.  
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0013] In FIGS.  1  to  3 , the strips each include a channel-shaped gripping part  2 , a soft hollow sealing part  4 , an external lip (termed a “cosmetic lip”)  6  and a soft sealing bead  7 . The strip is to be secured on a mount in the form of a flange which forms the frame of an opening in a motor vehicle body, such as a door opening or a luggage compartment opening. In the present case, the strips are suitable for fitting to the flange around a luggage compartment as will be explained in more detail below.  
     [0014] The strips are formed from extruded material  8  such as plastics or rubber material or a thermoplastic elastomer material. Alternatively, they may be produced by a moulding operation. Advantageously, a channel-shaped reinforcing element or carrier  10  is incorporated into the channel of the gripping part  2 . The carrier  10  may be made of suitable resilient material such as metal, for example. It may comprise an unapertured channel or a channel formed with slits or slots to increase its flexibility. Instead, it can comprise a series of U-shaped elements placed side by side along the length of the channel and either completely separate from each other or connected together by integral connecting links. Instead, the carrier  10  may be formed from wire, looped to and fro to form the required channel-shape. Other forms of carrier are possible. The purpose of the carrier is to increase the resilience of the gripping part  2 , as will be explained.  
     [0015] The carrier  10  may be incorporated into the extruded material during the actual extrusion process, using a cross-head extruder.  
     [0016] The extruded material  8  of the gripping part  2  is integrally formed with gripping elements  12 , 14 . The gripping elements  12  are in this example of the strip formed with a generally triangular cross-section. The gripping elements  14  have enlarged ends or feet  16  which are supported from the adjacent channel wall by thin connecting legs or webs  18 .  
     [0017] Although FIG. 1 shows three gripping elements  12  and two gripping elements  14 , there may be other numbers of these gripping elements. The gripping elements  12 , 14  extend longitudinally along the strip with constant cross-section.  
     [0018] The strip may have a hollow longitudinal chamber  20  to provide additional flexibility.  
     [0019] The extrusion process may be arranged so that different parts of the material have different hardness. For example, the material forming the gripping part  2  may be relatively hard, while the sealing part  4  may be softer, such as of cellular form. The cosmetic lip  6  and the bead  7  may be of intermediate hardness. The gripping elements  12  and  14  may be made of softer material.  
     [0020]FIG. 2 shows the strip of FIG. 1 placed in position on the mount or flange  22 . This flange is formed by the inner and outer body panels  24 , 26  of the vehicle which meet around an opening in the motor vehicle body. In this case, the flange  22  is the flange running around a luggage compartment opening in a motor vehicle body, and the gripping part  2  thus supports the sealing part  4  so that it projects vertically upwards and becomes partially compressed by the closing lid of the luggage compartment to provide a seal.  
     [0021] The cosmetic lip  6  is used to receive and hide the edge of a trim panel  28  on the inside of the luggage compartment. The sealing bead  7  makes sealing contact with the body panel  26 .  
     [0022] In order to provide effective support for the sealing part  4 , and to provide and maintain a pleasing appearance, it is very important that the gripping part  2  is held firmly on the flange  22 . This function is provided by the gripping elements  12 , 14 , which are pressed resiliently into contact with opposite sides of the flange  22  by the resilient carrier  10 . More particularly, and in accordance with a feature of the invention, enhanced gripping strength is achieved by the particular configuration of the gripping elements  14 . As shown in the Figures, the enlarged feet  16  provide relatively flat and relatively large contact surfaces  16 A; these relatively large areas thus increase the frictional force acting against the flange  22  for holding the gripping part  2  in position. The gripping force is further enhanced by the particular configuration of the gripping elements  14 . As shown in FIG. 1, each foot  16  tends to face obliquely towards the mouth of the channel of the gripping part  2  when the strip is not in position on the flange, the web  18  with its foot  16  pivotting on the gripping part  2  at the integral junction  30  between the web  18  and the channel side wall. However, as shown in FIG. 2, the contact between the flat surface  16 A of each foot  16  and the adjacent surface of the flange  22  causes the connecting legs  18  to extend substantially perpendicularly to the adjacent inside wall of the gripping part  2 . Because each foot  16  has foot portions  16 B and  16 C respectively on opposite sides of a plane through the connecting foot  16  and substantially perpendicular to the foot surface  16 A and to the flange  22 , there will be increased resistance to a force tending to pull the strip off the flange  22  (in the direction X): any such force would tend to pivot each foot  16  about the respective pivot point  30  where its web  18  integrally joins the channel side wall, so that the foot portions  16 C would bend away from the flange  5 . However, such bending movement would press the foot portions  16 B more strongly into contact with the flange, thus providing very high resistance to pull-off forces. Each web  18  increases progressively in thickness in the direction from the junction  30  towards the foot  16  giving a generally triangular shape as viewed in cross-section in the Figures, thus tending to fix the pivot point at the junction  30 .  
     [0023] Although one of the most significant requirements for the gripping part  2  is to provide a high resistance to pull-off forces, it is also of course required that the strip be relatively easy to mount in position on the flange. In other words, it should preferably have a low push-on force (that is, a force acting in the direction Y). A strip having a configuration shown in FIG. 1 will be relatively difficult to place in position on the flange because the features of the gripping elements  14 , which provide high resistance to pull-off forces, will also act to resist push-on forces. Thus, during fitting, the large area surfaces  16 A of the gripping elements  16  will make frictional contact with the side of the flange, and the connecting legs  16  will tend to bend into the depth of the channel (that is, in the opposite direction to that shown in FIG. 1), causing the foot portions  16 C to be pressed into tight frictional contact with the flange surface.  
     [0024] Therefore, it may be preferable to mount the strip on the flange by forming it initially into the configuration shown in FIG. 3 where the channel side walls are splayed slightly outwardly. This enables the gripping part  2  to be placed over the flange  22  without any difficulty. The channel side walls can then be forced into the configuration shown in FIG. 2, such as by using a special tool as described in our U.K. Patent Specifications Nos. 2212844 and 2215762 for example.  
     [0025]FIG. 4 shows a modified form of the strip which helps to overcome the problem of a high push-on force. As shown in FIG. 4, the gripping elements have feet  16  of modified shape. More specifically, each foot portion  16 B has an extension  16 D which is curved towards the adjacent inside side wall of the channel of the gripping part  2 . When the strip is placed onto the flange  22  and pushed into position in the direction Y (FIG. 2), the feet extensions  16 D make contact with the side wall of the channel, as shown in FIG. 5. “Over-tilting” of the feet  16  during the push-on process is now prevented, and this helps to reduce the push-on force. However, the feet extensions  16 D do not reduce the high resistance of the strip to pull-off forces.  
     [0026] A strip having gripping elements  14  with the configuration shown in FIGS. 4 and 5 can still be fitted, of course, in a configuration in which the side walls of the channel are initially splayed-apart—as shown in FIG. 6, the splayed-apart walls then being forced towards the flange in the manner explained in conjunction with FIG. 3.  
     [0027]FIGS. 7 a  to  7   j  show various modifications to the shape of the feet  14  which are possible.  
     [0028]FIG. 7 a  shows a foot generally having the same configuration as shown in FIGS.  1  to  3 .  
     [0029]FIG. 7 b  shows a foot having a modified shape to its surface  16 C, this surface having a concave shape to enhance the force between the portions  16 B and  16 C against the flange surface. In FIG. 7 c , the foot surface  16 C has a convex shape to increase the overall force between the foot and the flange surface.  
     [0030] The feet shown in FIGS. 7 d  to  7   f  have the foot extensions  16 D discussed above in relation to FIGS.  4  to  6 . The shapes of their surfaces  16 C respectively correspond to those shown in FIGS. 7 a  to  7   c.    
     [0031]FIGS. 7 g  to  7   i  show that the positive effect of the feet extensions  16 D (reducing the push-off force) can instead be achieved by providing protrusions  32  on the channel side wall, instead of the feet extensions. During the process of pushing the gripping part  2  onto the flange  22 , any tendency of the foot portions  16 B to tilt towards the channel side wall (thus undesirably increasing the push-on force) will be resisted by contact between the foot portions  16 B and the protrusions  32 .  
     [0032] In FIGS. 7 g  to  7   j , the surfaces  16 C of the feet respectively have the same shapes as shown in FIGS. 7 a  to  7   c.    
     [0033]FIG. 7 j  shows a thin flexible integral link  34  connecting the foot portion  16 C to the adjacent channel side wall. This link resists any tendency of the foot portions  16 B to tilt undesirably towards the channel wall during push-on, in the same way as the extensions  16 D or the protrusions  32 .  
     [0034] If the strip were to be fitted to a flange around a door opening, instead of around a luggage compartment opening, the sealing part  4  would be mounted on the outside of the side wall  2 A of the gripping part  2  instead of on the outside of its base. The sealing part would thus then be mounted in such a position as to be partially compressed by the closing door, therefore providing a sealing function.  
     [0035] However, it will be appreciated that the beneficial effects of the gripping elements  14  can be usefully provided when the strip is merely required to provide a trimming or finishing function—that is, it comprises merely a channel without the sealing part  4  and the cosmetic lip  6 .