Abstract:
A mechanically interlocking belt weatherstrip for a motor vehicle. The weatherstrip is formed by three separate components: a cover, a body and a sealing lip. The weatherstrip may be made from separate, all-extruded components, or may be a made from a combination of molded and extruded components. The weatherstrip is formed by snapping the body and the cover snap together to hold the sealing lip securely in place. Because the cover can be easily interchanged with a different cover, the cover can be made to include properties, such as color and gloss, desired by a particular motor vehicle manufacturer while the remaining components remain unchanged. Thus, the weatherstrip allows versatility of the selection of the separate components to meet the individual style and functional needs of a particular motor vehicle design.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to weatherstrips for motor vehicles and more specifically to a mechanically interlocked weatherstrip for window frames of a motor vehicle. 
     2. Related Art 
     Most motor vehicles are equipped with movable windows that slide in a window opening from an up or extended position that seals off the opening to a down position, retracted within the vehicle body, that opens all or a portion of the opening and allows an exchange of air between the inside and outside of the vehicle. A sealing device broadly referred to as a weatherstrip is disposed about the periphery of the window opening and provides an air and watertight seal between the vehicle body and the window. The interface between the body and the movable window at the lower extremity of the window opening is typically equipped with a weatherstrip denominated a beltstrip which aesthetically hides the interface and provides a wiper flange or blade for cleaning the window as the window extends and retracts from the body of the vehicle. 
     Recently, emphasis has been placed upon vehicle streamlining for drag reduction purposes and reduction of wind noise. To achieve these goals, design considerations such as the elimination of all gaps and channels, low profile configurations, overlapping of the beltstrip or weatherstrip on the glass for wind noise reduction, as well as installation ease, serviceability and durability have greatly increased significance. The challenge of achieving such goals depends upon the proper execution of such design considerations. 
     Beltstrips and weatherstrips are generally extruded or roll-formed in a complicated manufacturing process having many steps. Typically, a core metal structure is formed and coated with an extruded layer of synthetic elastomeric material to form a belt molding and then is then cut to length. A sealing strip having a flexible blade for contacting the window may be formed and coated in an extrusion process with rubber or similar material to form a base strip. An inner surface of the blade is generally flocked to provide a low friction coating for reducing friction between the blade and the window and to reduce the tendency of the weatherstrip and window to squeak. The sealing strip is usually affixed to the belt molding. The belt molding and the base portion of the sealing strip are usually notched at spaced locations. Clips are then inserted into the notches to affix the belt molding, sealing strip and clips. The clips also grip a flange edge formed on the door of the vehicle to hold the belt weatherstrip to the door of the vehicle. 
     The materials used to form the belt weatherstrip are typically a combination of thermoset elastomer or thermoplastic and thermoplastic elastomer. For example, an elastomer may be over extruded on a metal carrier and then a post assembled laminate strip of cosmetic film and metal that is roll formed into a C-configuration is mechanically fastened over a section of the front surface of the belt weatherstrip. 
     The requirement of cosmetic surfaces dictates that the surface area be made of specific thermoplastic, a decorative film, or consist of a painted metal while providing a seal to prevent air and water leakage. Conventional weatherstrips lack the flexibility to interchange the front surface in order to provide a different cosmetic appearance. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a mechanically interlocking weatherstrip assembled from distinctly separate components. 
     It is another object of the invention to provide a belt weatherstrip made by interlocking two separately molded thermoplastic parts and a functional elastomeric part. 
     To achieve these and other objects of the invention, the weatherstrip comprises a cover, an body and a sealing lip that mechanically interlock with each other to form the weatherstrip. 
     The cover can be made of a suitable thermoplastic material and may include properties, such as color and gloss, designed for a particular motor vehicle manufacturer while the remaining components remain unchanged. This feature provides versatility of the selection of the separate components to meet the individual style and functional needs of a particular motor vehicle design. In addition, the weatherstrip may be made from separate, all-extruded components, or may be a made from a combination of molded and extruded components. 
     These and other aspects and advantages of the invention are described or apparent from the following detailed description of the preferred embodiments and appended drawings wherein like reference numbers refer to the same element, feature or component. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments are described with reference to the drawings in which: 
     FIG. 1 shows a partial side elevation of a motor vehicle; 
     FIG. 2 shows a partial perspective view of a weatherstrip according to a preferred embodiment of the invention; 
     FIG. 3 shows a cross-sectional view of a weatherstrip according to the preferred embodiment of the invention taken along lines  3 — 3  of FIG. 2; and 
     FIG. 4 shows a partial perspective view of a weatherstrip according to another preferred embodiment of the invention. 
     FIG. 5 shows a second alternative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings, FIG. 1 shows a partial side elevation of a four-door motor vehicle  10  having a front door  12  and a rear door  22 , a movable front window  14  and a movable rear window  24 , a mirror patch  16 , a fixed window  26 , and a beltstrip or weather strip  18  attached to the front door  12  at an interface between the front window  14  and the front door  12 . 
     Similarly, the weatherstrip  18  may be attached to the rear door  22  at an interface between the rear window  24  and rear door  22 . The weatherstrip  18  extends longitudinally along both the lower edge of the front window  14  and the lower edge of the rear window  24  and operates to aesthetically conceal the interface between the front door  12  and the front window  14  and the rear door  22  and the rear window  24 , as well as to provide a seal for air and water leakage therebetween. 
     The weatherstrip  18  of the invention is shown in FIGS. 2 through 4. The weatherstrip  18  preferably comprises three separate components: a cover  30 , a body  40  and a sealing lip  50 . 
     The cover  30  includes a side wall  32 , an upper camming projection  34 , a struck out portion  36 , and a transition portion  38 . 
     The cover  30  serves as an outer decorative component made from material to meet color, gloss and weatherability requirements of the individual motor vehicle manufacturer. The cover  30  may be made of a wide variety of materials and may be molded or extruded using a process well-known in the art. 
     In the preferred embodiment, the cover  30  is made preferably of a colored, weatherable grade, acrylic-styrene-acrylonitrile polycarbonate (ASA/PC) alloy. However, the cover  30  may also be made of combinations of nylon alloy materials, such as ASA, thermoplastic (TPO), polyvinyl chloride (PVC) and the like. Also, the cover  30  may be made of a film laminated thermoplastic material, such as acrylonitrile-butadiene-styrene (ABS), polyethylene teraphthalate (PET) and polybutylene teraphthalate (PBT) and the like. In addition, the cover  30  may be made of body matched painted thermoplastic material from any variety of thermoplastic families based on ABS, PET, PBT, polyamide (nylon) (PA) and the like. 
     The body  40  includes a projecting portion  42  having an upper camming projection  43  and a lower camming projection  44  and a lip portion  46  having an upper camming projection  48 . In the preferred embodiment, lip portion  46  is located at spaced apart locations to align with a transition portion  38  of the cover  30 . 
     In one embodiment of FIGS. 2 and 3, the projecting portion  42  of the body  40  is formed to continuously extend longitudinally along the front window  14  or the rear window  24  of the vehicle  10 . 
     The body  40  may be made from any inherently dimensionally stable thermoplastic material to meet dimensional stability and exterior motor vehicle requirements. In the preferred embodiment, the body  40  is made from material substantially identical to the cover  30  and may be molded or extruded. However, the body  40  may also be made from PA material, glass filled PA, and the like. 
     The sealing strip or lip  50  includes a blade portion  52  having a low-friction, inner sealing surface  54  and an outer surface  56  and a lower interlocking portion  58 . The inner surface  54  is preferably made of a low-friction material, such as polyester flock, a low-friction coating, a low-friction film and the like. The outer surface  56  may be coated with coating or film or may be uncoated depending on design specifications. 
     The sealing lip  50  is preferably made of a flexible, elastomeric material, such as rubber, ethylene-propylene-diene-monomer (EPDM), Santoprene® thermoplastic elastomer (TPE) and the like. Santoprene® is a registered trademark of Advanced Elastomer Systems, L. P. of Akron, Ohio. The sealing lip  50  may be molded or extruded using a process well-known in the art. 
     When the weatherstrip  18  is installed on a vehicle  10 , the sealing lip  50  functions as a wiper so that when the front window  14  or the rear window  24  is raised, any moisture or other residue on the window will be wiped away. The sealing lip  50  also prevents the leakage of moisture or other residue into the door panel and reduces the amount of noise transferred to the interior of the vehicle  10 . 
     The lower interlocking portion  58  defines a plurality, preferably three, generally semi-circular projections or ribs  60  preferably oriented at right angles to one another and generally to the blade portion  52  of the sealing strip  50 . Thus, the lower interlocking portion  58  in this embodiment generally has a cloverleaf-shaped cross section. The semicircular projections  60  fit into recesses formed in the cover  30 , the body  40  and a recess formed by both the cover  30  and the body  40 . To mechanically interlock the above-mentioned separate components to form the weatherstrip  18 , the lower interlocking portion  58  of the sealing lip  50  is positioned to abut the camming projection  34  of the cover  30  as shown in FIG.  3 . The lip portion  46  of the body  40  is urged toward the transition portion  38  until the lip portion  46  encounters the transition portion  38 . The camming projection  48  of the body  40  is urged toward the struck out portion  36  of the cover  30 . The inherent resiliency of the lip portion  46  of the body  40  abutting against the transition portion  38  of the cover  30  urges the camming projection  48  upward and inward towards the struck out portion  36 . As the camming projection  48  is biased towards the cover  30 , an audible sound like a “click” is emitted, indicating that the body  40  is properly snapped in place. When properly snapped in place, the upper camming projection  43  of the body  40  is biased towards the camming projection  34  of the cover  30  to securely hold the sealing lip  50  in place and to mechanically interlock the weatherstrip or beltstrip  18 . 
     Alternatively, the cover  30  and the body  40  may first be properly snapped in place. Then, the interlocking portion  58  may be slid longitudinally in the channel formed between the camming projection  34  of the cover  30  and the upper camming projection  43  of the body  40  to form the mechanically interlocked weatherstrip or beltstrip  18 . 
     To securely affix the weatherstrip  18  to the vehicle  10 , the lower camming projection  44  of the mechanically interlocking weatherstrip  18  may then be used to engage a portion of the front door  12  and the rear door  22 , for example, the pinch weld (not shown) in a manner well-known in the art. It should be appreciated that the weatherstrip  18  may be attached to any piece of material that has a surface or edge that can be gripped by the lower camming projection  44 . 
     It should be appreciated that the invention is not limited to the particular geometric configuration or shape of the body  40  and, in particular the projection portion  42  and the lower camming projection  44 . It is envisioned that the body  40  can be adapted to a variety of cross-sectional shapes so that the weatherstrip  18  can accommodate and be installed in a wide variety of door configurations. It is also envisioned that the body  40  may also include a steel reinforcing member to provide rigidity to the body  40  by extruding EPDM material over a steel carrier using a process well-known in the art. 
     FIG. 4 shows an alternate embodiment of the weatherstrip or beltstrip  18 ′. In the alternate embodiment of the invention, the sealing lip  50  is substantially identical to the embodiment shown in FIGS. 2 and 3. However, the cover  30 ′ shown in FIG. 4 includes a plurality of transition portions  38 ′ that are located at spaced intervals in the longitudinal direction of the weatherstrip  18 ′, rather than a single, continuous transition portion  38  shown in FIGS. 2 and 3. Otherwise, the cover  30 ′ is substantially identical to the cover  30 . 
     Likewise, the body  40 ′ shown in FIG. 4 includes a plurality of projecting portions  42 ′ and lower camming projections  44 ′ are located at spaced apart locations along the longitudinal direction of weatherstrip  18 ′, rather than a single, continuous projecting portion  42  and lower camming projection  44 . Otherwise, the body  40 ′ is substantially identical to the body  40 . 
     As readily apparent from FIG. 4, each transition portion  38 ′ of the cover  30 ′ aligns vertically with each projection portion  46 ′ of the body  40 ′ along the length of the weatherstrip  18 . It should be appreciated that the weatherstrip  18 ′ contains a sufficient number of projecting portions  42 ′ and lower camming projections  44 ′ to properly attach the weatherstrip  18 ′ to the vehicle  10  in a manner similar to the weatherstrip  18 . The cover  30 ′, the body  40 ′ and the sealing lip  50  may be assembled in the same manner as the cover  30 , the body  40  and the sealing lip  50  of the weatherstrip  18  as described above to form the mechanically interlocked weatherstrip  18 ′. 
     FIG. 5 shows a second alternate embodiment of the weatherstrip or beltstrip  18 ″. In this alternate embodiment, the cover  30  and the body  40  are substantially identical to weatherstrip  18  of FIGS. 1 through 3. However, the sealing lip  50  with the lower interlocking portion  58  having a clover-leaf cross-sectional shape is replaced with a sealing lip  50 ′ with a lower interlocking portion  58 ′ having an elongate cross-sectional shape. The sealing lip  50 ′ also includes an outer surface  56 ′ and an inner surface  58 ′ with a flock-like coating similar to the other embodiments of the invention. The cover  30 , the body  40  and the sealing lip  50 ′ may be assembled in the same manner as the cover  30 , the body  40  and the sealing lip  50  of the weatherstrip  18  as described above to form the mechanically interlocked weatherstrip  18 ″. 
     It should be readily apparent that the cover  30  and the body  40  of the weatherstrip  18 ″ may be replaced with the cover  30 ′ and the body  40 ′ of the weatherstrip  18 ′. It should also be readily apparent that the weatherstrip  18 ″ can be attached to the vehicle  10  in a manner similar to the other embodiments of the invention. 
     In view of the foregoing, the invention allows versatility of the selection of the separate components to meet the individual style and functional needs of a particular motor vehicle design. In addition, the invention may be made from separate, all-extruded components, or may be a made from a combination of molded and extruded components to provide the most cost-effective method of manufacturing. 
     While this invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein are intended to be illustrative, rather than limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.