Abstract:
The present invention is a physical barrier for an orifice in a panel member which includes a plastic carrier and a patch adapted to adhere to said carrier and the panel member. The present invention also includes a method of sealing an orifice in a metal panel member with a plastic carrier. Lastly, the present invention includes a thermoplastic which adheres to both plastic and metal upon the application of heat.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to devices and methods for sealing orifices in panel members.  
         BACKGROUND OF THE INVENTION  
         [0002]    Physical barriers are commonly used to seal orifices in certain objects, such as panel members in motor vehicles, buildings, household appliances, etc. These barriers normally are used to prevent physical materials, fluids, and gases, such as environmental contaminants, fumes, dirt, dust, moisture, water, etc., from passing through the orifice or cavity. For example, an automotive panel, such as a door panel, typically has several small orifices in the sheet metal, which are created for various reasons during manufacturing. Further, various structural components of automobile bodies have a variety of orifices, hollow posts, cavities, passages and openings that can allow contaminants from the engine and the roadway into the passenger compartment. These holes, orifices, and cavities are typically barricaded with duct tape, butyl-based plastic patches, and sealing plugs made from foam, rubber or some other material. Another known physical barrier for cavities involves introducing a foam product into the cavity, and using a fiberglass matting to fill in the cavity.  
           [0003]    One type of known physical barrier is a combination of a metal carrier and a patch of heat flowable material. The metal carrier is inserted into and retained in the orifice to be sealed. Next, the patch is overlaid on the carrier and heated so as to form a seal over the orifice. The metal carrier supports the center of the patch so as to prevent the patch from collapsing into the orifice. This solution is unsatisfactory for a number of reasons. First, the metal carrier is difficult to install into the orifice. Namely, a force multiplying tool and/or a machine is needed to apply a large amount of force to sufficiently flex the retaining means on the metal carrier to allow installation. Second, the metal carrier is heavy while also being relatively expensive to manufacture. The use of other materials for the carrier has previously been limited because patch materials have not been available which adheres to disparate materials. For example, known patches adhere only to metal. Thus, previously both the panel member and the carrier were required to be metal.  
           [0004]    Consequently, there is a need for a physical barrier that overcomes one or more of these problems.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention is a physical barrier for an orifice in a panel member which includes a plastic carrier and a patch adapted to adhere to said carrier and the panel member. The present invention also includes a method of sealing an orifice in a metal panel member with a plastic carrier. Lastly, the present invention includes a thermoplastic material which adheres to both plastic and metal upon the application of heat. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    In the drawings:  
         [0007]    [0007]FIG. 1 a  shows an expanded view of a physical barrier according to the present invention.  
         [0008]    [0008]FIG. 1 b  shows a perspective view of a physical barrier according to the present invention.  
         [0009]    [0009]FIG. 2 shows an exploded view of a physical barrier according to the present invention.  
         [0010]    [0010]FIG. 3 a  shows a perspective view of a carrier according to the present invention.  
         [0011]    [0011]FIG. 3 b  shows a perspective view of a physical barrier according to the present invention.  
         [0012]    [0012]FIG. 4 a  shows a perspective view of a carrier according to the present invention.  
         [0013]    [0013]FIG. 4 b  shows a perspective view of a physical barrier according to the present invention.  
         [0014]    [0014]FIG. 5 a  shows an expanded view of a physical barrier according to the present invention.  
         [0015]    [0015]FIG. 5 b  shows a perspective view of a physical barrier according to the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0016]    The physical barrier  10  of the present invention consists of a plastic carrier  12  and a sealer patch  14  as shown in FIG. 1. Carrier  12  includes a deck  16  and at least one snap-fit fastener  18 . Together, carrier  12  and patch  14  form physical barrier  10  for an orifice in a panel member, where deck  16  supports the center of patch  14 , such that patch  14  does not collapse into the orifice. Carrier  12  and patch  14  may be shaped and sized to accommodate any orifice in the panel member.  
         [0017]    The at least one snap-fit fastener  18  in FIG. 1 is a plurality of protrusions  20  which are generally perpendicular to the plane of deck  16 . These protrusions encompass a majority of the perimeter defined by the protrusions. Protrusions  20  include an edge  22  and a holding surface  23 .  
         [0018]    The at least one snap-fit fastener  18  in FIGS. 2, 3 and  4  is a plurality of S-shaped clips  24 . The long axis of S-shaped clips  24  lies in the place of the carrier deck  16 . S-shaped clips  24  include a holding surface  25  and may include a tail  26 .  
         [0019]    The at least one snap-fit fastener  18  in FIG. 5 is a circumferential trough  28  with a lip  30  included on a continuous circumferential outer wall  32  of trough  28 . Outer wall  32  also includes a holding surface  33 .  
         [0020]    Snap-fit fasteners  18  may be any fastener which causes carrier  12  to snap into position, i.e., into the orifice to be sealed. The snap-fit fasteners illustrated in FIGS.  1 - 5  are not meant to be limiting, but rather only demonstrative.  
         [0021]    As shown in FIGS. 1, 4 and  5 , deck  16  may include a circumferential ridge  34  which defines a recess into which a protrusion (not shown) on patch  14  may be placed. This helps ensure that the patch is properly place on the carrier. The ridge-protrusion combination also helps to the patch remain in place during insertion of the physical barrier into the orifice.  
         [0022]    As shown in FIGS. 3 and 4, carrier  12  may also include multiple legs  36 , which are positioned between snap-fit clips  24  and are oriented away from patch  14 .  
         [0023]    Patch  14  is made of a thermoplastic material that is flowable when activated with heat and that adheres to both plastic and metal. Any thermoplastic which adheres to both metal and plastic is suitable for use in the present invention. Adherence to both metal and plastic is an attribute that has not been previously produced in thermoplastic materials.  
         [0024]    In one useful embodiment, patch  14  contains an ethylene-vinyl acetate (EVA) copolymer combined with a styrene butadiene rubber (SBR). One useful EVA is the ELVAX® 400 series from Dupont. A suitable SBR is the 1006 material from Ameripol Synpol Corp of Akron, Ohio.  
         [0025]    Patch  14  may also include suitable fillers such talc, mica, tall oil rosin and/or other conventional fillers for thermoplastics. Talc selected for inclusion in patch  14  may be a highly pure platy talc such as one or more chosen from the 9900 series from Polar Minerals of Wellsville, Ohio, while utilized mica may be a phlogopite mica such as one or more chosen from the 5000 series, also from Polar Minerals. A suitable tall oil rosin may be selected from the SYLVAROS series from Arizona Chemical Co. of Jacksonville, Fla.  
         [0026]    In one embodiment, EVA is present in amounts of 10-40 wt %, while SBR is present in amounts of 5-35 wt %. The balance includes 5-22 wt % talc, 10-45 wt % mica and 10-30 wt % tall oil rosin. A particularly useful material for patch  14  is a composition of 29 wt % EVA, 16 wt % SBR, 12 wt % talc, 26 wt % mica and 17 wt % tall oil rosin.  
         [0027]    Carrier  12  may be made of conventional plastic materials, with the only consideration being the activation temperature for patch  14 . Thus, carrier  12  must be able to maintain its physical rigidity at the activation temperature; i.e., carrier  12  should not melt at temperatures used in the chosen heat source. When used in vehicles, the carrier should withstand temperatures normally utilized in the paint and coating drying ovens. While metals may be used, plastics are preferred because of the reduced amount of force needed to install a plastic carrier as compared to a metal carrier. One useful plastic material is nylon.  
         [0028]    Physical barrier  10  may be made by conventional methodologies. Carrier  12 , separate from patch  14 , can be formed, inter alia, by vacuum forming, injection molding or extrusion. Patch  14  may be formed by similar techniques. Once individually formed, carrier  12  and patch  14  may be attached to each other prior to installation into a cavity. An appropriate adhesive may be used, but heat staking is preferred. Heat staking is a process by which two plastic parts are effectively spot welded together.  
         [0029]    Methodologies of making carrier  12  and patch  14  parts into one integral piece may also be utilized. Insert molding, which uses two molds, and two shot molding, which uses one mold, are suitable methods of making barrier  10  where carrier  12  and patch  14  are integral.  
         [0030]    The installation of barrier  10  is now described. Barrier  10  is inserted into the orifice to be sealed. The snap-fit fasteners flex as carrier  12  is seated in the panel member. Edges  22 , tails  26  or lip  30  ensure that carrier  12  is not over inserted into the orifice. Protrusions  20 , legs  36  or outer wall  32  ensures that carrier  12  is centered and not twisted in the orifice to be sealed. Holding surfaces  23 ,  25 ,  33  are the locations on the respective snap-fit fasteners which abut the panel member after carrier  12  has been installed.  
         [0031]    By centering carrier  12 , the maximum amount of strain all snap-fit fasteners  18  have to endure is significantly reduced. This reduces the strength of snap-fit fasteners that are needed to properly install barrier  10 , which in turn reduces the amount of force needed to install barrier  10 . Thus, force-multiplying tools or machines are not needed to install the barriers of the present invention.  
         [0032]    After installation, patch  14  is activated to produce a contaminant-tight seal. Patch  14  is activated by heating the patch sufficiently to cause it to flow. Upon cooling, patch  14  will adhere to carrier  12  and the panel member surrounding the orifice. Any source of heat may be used to activate patch  14 . One particularly useful heat source is an oven associated with drying coatings and paints on vehicles. These ovens operate at multiple temperatures depending on the coating or paint being dried, and typically operate between about 175° F. and about 400° F.  
         [0033]    Plastic carriers with snap-fit fasteners are highly advantageous over known metal carriers because no separate tools or machines are necessary to insert the carrier into a cavity. Metal carriers often require a tool to bend retention tabs at the time of installation. Furthermore, the amount of force required to properly seat the carrier in the orifice is significantly less with a plastic carrier compared to a metal carrier. Plastic carriers may be installed by hand. The reduced amount of required installation force means that less problematic installations. The use of plastic carriers is permitted through the use of a patch which will adhere to disparate materials, i.e., plastic and metal. Such a patch has not previously been available.  
         [0034]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.