Abstract:
A drain seal for connecting a drain tube to a support structure includes a molded unitary body having first and second moldingly joined portions, each formed of dissimilar durometer materials. The first portion is formed to sealingly join the body to a drain tube. The second portion is formed to mount the body in an aperture in a support structure. A bore extends completely through the body.

Description:
BACKGROUND 
   Sun roof assemblies are a common option in automotive vehicles. Such sun roof assemblies can be of the tilting and/or sliding type and have a panel mounted in a roof opening in the vehicle. The panel is moveably supported in a pair of longitudinally extending guide rails affixed to the vehicle roof A trough extends around the edge of the roof opening and collects water when the sun roof panel is open or if any water passes through the sealing structure typically employed with the sun roof panel. This drain trough is connected to one or more drain tubes which are typically run through the vehicle body side pillars. A lower end of the tube is open to allow water to be discharged from the vehicle. 
   The bottom of the drain tube receives a drain seal which provides the dual functions of fixing one end of the drain tube to the vehicle body structure as well as providing a small, one way opening to allow water collected by the drain tube to exit the drain tube while at the same time preventing the entry of water or debris into the lower end of the drain tube. 
   Prior drain seals have been formed of two separate elements which are joined together, typically by an adhesive. The two different elements have different shapes to serve different functions as well as being formed of different materials to again serve specific, different functions. One of the elements is formed of a softer durometer material to serve as a seal to the vehicle body structure. The other element is typically formed of a higher durometer material for fixed mounting of the drain seal to the drain tube. 
   While effective, the prior art drain seals involve multiple parts which must be joined together. This increases the cost of the drain seal. 
   It would be desirable to provide a drain seal for an automotive vehicle which can be manufactured at a lower cost while still providing all of the required functions of a drain seal. 
   SUMMARY 
   The inventive drain seal provides all the functions of a typical drain seal for a sun roof drain tube while, at the same time, having a unitary one piece construction thereby eliminating secondary assembly operations for lower manufacturing costs and improved reliability. 
   The inventive drain seal mounts a drain hose to a vehicle support structure while allowing drainage of fluid from the attached drain hose. In one aspect, the drain seal includes a molded, unitary, monolithic body having first and second moldingly joined portions, the first portion formed of a material having a first durometer and carrying means for sealingly joining the body to a drain hose. The second portion is formed of a material having a second durometer, and includes means for mounting the body in an aperture in a structure. A bore extends through the body from one end of the first portion to an opposite end of the second portion. A bond between the first and second portions is a chemical bond. 
   At least one enlargement formed on the first portion. The at least one enlargement has an outer diameter larger than an inner diameter of a drain hose. A surface having a diameter greater than a diameter of the stem of the first portion. An annular recess is formed between the surface and a mounting end of the second portion, the recess defining a surface for receiving a panel in the body. The first portion is joined to the second portion at the surface of the first portion. A drain end extends from the surface. The drain end has exterior surface tapering inward along two mutually opposed axes. At least one slot is formed in the drain end of the second portion. The at least one slot is fluidically coupled to the bore extending through the body. Optionally, a pair of intersecting slots are formed in the drain end of the second portion and extending from the bore through the body. 
   In another aspect, the present invention is a method of forming a drain seal including the steps of molding a unitary body of first and second moldingly joined portions in a double shot molding operation, forming the first portion of a material having a first durometer, forming the second portion of a material having a second lower durometer, forming a bore extending through the body from one end of the first portion of the body to an opposite end of the second portion of the body, forming the first durometer material of a higher durometer than the second durometer material of the second portion of the body, forming a sealing means on the first portion of the body for joining the body to a drain hose, forming a mounting means on the second portion of the body for mounting the body in an aperture in a structure, forming enlarged ends for the first and second portions, the enlarged ends moldingly joined and forming an annular undercut or recess between a drain and of the second portion of the body and an end surface of the body. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The various features, advantages and other uses of the present invention will become more apparent by referring to the following detailed description and drawing in which: 
       FIG. 1  is a perspective view of a drain seal constructed in accordance with the teachings of the present invention; 
       FIG. 2  is a side elevational view of the drain seal shown in  FIG. 1 ; 
       FIG. 3  is a cross-sectional view generally taken along line  3 — 3  of  FIG. 1 ; and 
       FIG. 4  is a cross-sectional view generally taken along line  4 — 4  of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Referring now to  FIGS. 1–4 , there is depicted a drain seal  10  constructed in accordance with the teachings of the present invention. The drain seal  10  is uniquely formed as a one piece, monolithic body of two dissimilar different durometer materials which are chemically bonded together. The drain seal  10  includes a first element or portion  12  having a base  14  of a generally dome-like shape and a hemispherical shaped cross-section as shown in  FIG. 2  extending from a central axis to an exterior peripheral edge. As also shown in  FIG. 2 , the peripheral edge  16  depends in an arcuate fashion with respect to the central axis. 
   A leg  17  extends centrally from one side of the base  14 . A stem  18  projects from an opposite side of the base  14 . Tube joining means  20  are formed on the stem  18 . By way of example only, the tube joining means includes one or more angularly extending barbs  22 . The barbs  22  forcibly expand a drain tube  23  shown in  FIG. 3 , outward during insertion of the stem  18  into one end of the tube  23  and conforms the tube  23  which is generally formed of a softer durometer material, to the shape of the barbs  22  thereby resisting separation of the tube  23  from the drain seal  10 . 
   A longitudinal bore  24  extends through the stem  18 , the base  14  and the lower leg  17 . 
   According to the present invention, the first element  12  is formed of a high durometer material, such as high density polypropylene (HDPP). 
   The drain seal  10  also includes a second element or portion  40  which is formed of a lower durometer material than the material used to form the first element  12 . By example only, the second element  40  is formed of a thermoplastic rubber (TPR), such as SANOPRENE. Again, by example, 60 durometer SANOPRENE may be employed as the material for the second element  40 . 
   While the material used to form the second element  40  is dissimilar from the material used to form the first element  12  of the drain seal  10 , the two materials are selected so as to form a chemical bond during a two shot molding operation. 
   For example, the first element  12  can be initially formed in a mold. While still in the mold, material for the second element  40  is injected into the mold and, due to the elevated temperatures associated with the molding operation, chemically bonds to the material forming the first element  12  to form a monolithic, one-piece structure for the drain seal  10 . 
   As shown in  FIGS. 1–4 , the second element  40  has an upper rim  42  formed with a peripheral edge  44  and having a generally dome-shaped cross-section. The rim  42  contacts the base  14  of the first element  12 . A central open-ended recess  46  is formed in the second element  40  complementary to and receiving the central leg  17  of the first element  12  as shown in  FIG. 4 . 
   It should be noted that while the recess  46  has been described as a structural feature of the second element  40 , it will be understood that the recess  40  is not actually preformed, but merely defines wall structure which surrounds or is formed about the leg  17  of the first element  12  when the second element  40  is double shot molded about the first element  12 . 
   As shown in  FIG. 1 , when the second element  40  is molded about the first element  12 , the rim  42  of the second element  40  will surround the inner surface and the peripheral edge  16  of the base  14  of the first element  12 . These mating surfaces define the interface in which a chemical bond is formed between the materials forming the first and second elements  12  and  40  to unitarily join the first and second elements  12  and  40  into a unitary, monolithic, one piece structure. 
   The second element  40  includes a lower portion  46  which is formed with opposed major sidewalls  50  and  52  and an intervening, opposed, side edges  53  and  54  all of which taper in two axes from a larger diameter first end  56  to a smaller diameter second end  58 . 
   The second element  40  has a mounting portion formed by an undercut or recess  60  between the inner surface of the rim  42  and the first end  56 . The recess  60  has a generally annular shape extending inward from an open end adjacent the outer surface of the side walls  50  and  52  and the side edges  53  and  54 . 
   The softer durometer material used to form the second element  40  provides compression to enable the second element  40  to be inserted through an aperture  64  in a vehicle body structure, such as a sheet metal panel  66  shown in  FIG. 2 , until the inner edges of the panel surrounding the aperture slide into the recess  50  in the second element  40 . The adjacent rim  42  of the second element  40  and the base  14  of the first element  12  provide an ergonomic surface to facilitate the insertion of the drain seal  10  through an aperture in a vehicle support structure or panel. Further, the arcuate shape of the rim  42  of the second element  40  and the base  14  of the first element  12  provide a resiliency or biasing force against the panel  66  to assist in retaining the drain seal  10  in the vehicle support structure or panel  66 . 
   As shown in  FIGS. 1–4 , the lower end of the second element  40  has at least one and preferably a pair of intersecting slots  70  and  72  formed at the end  58  of the second element  40 . The slots  70  and  72  are formed as open-ended slots extending inward from the second end of the second element  40 . The slots  60  and  62  intersect at the central axis of the second element  40  and are fluidically coupled to a bore  74  extending through the second element  40  and the contiguous bore  24  extending through the first element  12 . The slots  60  and  62  facilitate egress or drainage of fluid through the bores  24  and  74  in the drain seal  10  regardless of the orientation of the vehicle. 
   Thus, to form the drain seal  10 , the first element  12  is initially formed in a mold. While the material forming the first element  12  is still at an elevated temperature, a different material used to form the second element  40  is injected into the mold and joins to the base  14  of the first element  12  at the interface described above when the rim  42  is formed as part of the second element  40 . 
   Next, the stem  18  of the first element  12  of the drain seal  10  is inserted into an open end of a drain tube  23  to fixedly join the stem  18  to the drain tube  23  and to establish fluid communication between the bores  24  and  74  in the drain seal  10  with the interior bore in the drain tube  23 . 
   It should be noted that the assembly of the drain seal  10  to the drain tube  23  can take place in the manufacturing facility of the sunroof or other structure using the drain tube  10 . This enables the drain tube  10  to be shipped to the vehicle assembly plant as part of the overall sunroof or other structure which contains the drain tube  10 . 
   When the sunroof or other structure is mounted in a vehicle, drain tube  23  and attached drain seal  10  is routed through the appropriate vehicle body structure, such as one of the side pillars. The installer then grasps the base  14  and rim  42  and forcibly urges the lower portion  46  of the second element  40  through the aperture  64  in the vehicle body structure or panel  66  until the panel  66  snaps into the recess  60  in the second element  40 . It should be noted, as shown in  FIG. 3 , that the engagement of the panel  66  in the recess  60  causes a deformation of the peripheral edges of the rim  42  and possibly the base  14 . This causes an inherent resilient force to be formed in the rim  42  and possibly the base  14  which biases the drain seal  10  into engagement with the panel  66 . 
   The slots  70  and  72  in the second end  58  of the second element  40  of the drain seal  10  are now positioned to provide a drainage outlet for water flowing through the drain tube  23  and the bores  24  and  74  in the drain seal  10 .