Abstract:
A grommet includes a body having a first wall and a second wall. A passageway extends from the first wall to the second wall, and a service port extends from a first end adjacent to the first wall to a second end adjacent to the second wall. A first cap is integral with the first wall and covers the first end of the service port. Similarly, a second cap is integral with the second wall and covers the second end of the service port.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates in general to grommets that are used in holes formed through panels in vehicles to facilitate the passages of wires or other articles therethrough. In particular, this invention relates to an improved structure for a grommet that is more effective and less expensive than known grommets. 
     Most vehicles are provided with one or more panels or similar barriers that separate one portion of the vehicle from another. For example, a firewall is commonly provided in a vehicle to separate an engine compartment thereof from a passenger cabin. In many instances (both when the vehicle is manufactured and when installing an aftermarket device), it may be necessary or desirable for one or more wires or other articles to pass through these panels. To accommodate this, it is known to provide one or more holes through the panel to allow the wire or other article to pass therethrough. 
     However, the existence of such a hole can at least partially defeat the main purpose of the panel, which is to separate one portion of the vehicle from another. For example, a hole formed through a firewall can undesirably provide a pathway for water and other contaminants to pass from the engine compartment of the vehicle into the passenger cabin. Also, the presence of such a hole can undesirably provide a conduit through which noise can pass from the engine compartment of the vehicle into the passenger cabin. Lastly, the formation of such a hole can create a relatively sharp edge, which could cause damage to the wire or other article extending therethrough. 
     To address these problems, it is known to provide a grommet in the hole formed through the panel. Typically, the grommet includes a hollow cylindrical body that is formed from a plastic or elastomeric material. One or more flanges may be provided on the hollow cylindrical body to engage opposed sides of the panel to retain the grommet within the hole. The wire or other article extends through the hollow cylindrical body of the grommet The grommet minimizes the amount of open space extending through the panel, thereby minimizing the size of the pathways for contaminants and noise to pass from the engine compartment of the vehicle into the passenger cabin. Also, the grommet protectively covers any relatively sharp edges that might be present on one or both of the opposed sides of the panel, thereby protecting the wire or other article extending therethrough. 
     As mentioned above, the need for a hole through a firewall of a vehicle may arise not only when the vehicle is manufactured, but also later when installing an aftermarket device on the vehicle. To facilitate the installation of an aftermarket device on the vehicle, it is known to provide a grommet with two or more passageways, a first passageway that is used when the vehicle is initially manufactured and a second passageway that may be used when an aftermarket device is subsequently installed on the vehicle. The provision of these two or more hollow passageways eliminates the need to form a second, separate hole through the panel. 
     Although known grommets having multiple passageways have functioned satisfactorily, it would be desirable to provide an improved structure for a grommet that is more effective and less expensive than known grommets. 
     SUMMARY OF THE INVENTION 
     This invention relates to an improved structure for a grommet that is more effective and less expensive than known grommets. The grommet includes a body having a first wall and a second wall. A passageway extends from the first wall to the second wall, and a service port extends from a first end adjacent to the first wall to a second end adjacent to the second wall. A first cap is integral with the first wall and covers the first end of the service port. Similarly, a second cap is integral with the second wall and covers the second end of the service port. 
     Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional elevational view of a prior art grommet 
         FIG. 2  is a perspective view of a first embodiment of a grommet in accordance with this invention. 
         FIG. 3  is a sectional elevational view taken of the first embodiment of the grommet along the line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a sectional elevational view similar to  FIG. 3  showing the first embodiment of the grommet installed in a hole formed through a panel and having first and second wires extending therethrough. 
         FIG. 5  is a sectional elevational view of a second embodiment of a grommet in accordance with this invention. 
         FIG. 6  is a sectional elevational view of a third embodiment of a grommet in accordance with this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, there is illustrated in  FIG. 1  a grommet, indicated generally at  10 , that is conventional in the art. The prior art grommet  10  includes a first tubular port  12  that extends from a body portion  14 . The prior art grommet  10  also has a second tubular port  16  that extends from the body portion  14 . The first tubular port  12  and the second tubular port  16  are arranged generally orthogonally, although it is known to orient them otherwise. The first tubular port  12  and the second tubular port  16  are adapted to accommodate a wiring harness (not shown) that extends therethrough. The second tubular port  16  has one or more annular ridges  18  provided on an inside surface thereof to restrain movement of the wire harness relative to the prior art grommet  10  and to better accommodate wiring harnesses of differing diameters than would a smooth inside surface. An annular groove  20  is provided in the periphery of the prior art grommet  10  to engage opposed sides of a panel (not shown) to retain the prior art grommet  10  within a hole extending through the panel. 
     The prior art grommet  10  has a service port  22  provided therein that facilitates the passages of additional wires (not shown) through the prior art grommet  10 , such as when adding a new wire to replace an existing broken wire in the wire harness or a service fix requires running an additional wire. The service port  22  has a first end  24  that is closed with a first cap  26 . The first cap  26  is formed integrally with the remainder of the prior art grommet  10 . When the need for the service port  22  arises, the first cap  26  is removed from the prior art grommet  10  (such as by cutting) in order to provide access to the service port  22 . 
     The prior art grommet  10  is a double-walled grommet that includes a first wall  28  and a second wall  30 . The double-walled configuration serves to reduce the amount of noise that can pass through the grommet more than a single-walled grommet would. The first and second walls  28  and  30  of the prior art grommet  10  define an internal port space  32 . The first tubular port  12  and the second tubular port  16  both communicate with the internal port space  32  and together define a passageway that extends from the first wall  28  to the second wall  30 , through which the wiring harness (not shown) can pass when it is installed. The service port  22  also extends from the first wall  28  to the second wall  30  of the prior art grommet  10 . The service port  22  is separated from the internal port space  32  by a service port wall  34 . The service port wall  34  extends from the first wall  28  to the second wall  30  and serves to isolate the service port  22  from the internal port space  32 . 
     Because the service port  22  is only blocked at the first end  24 , it provides a relatively small amount of insulation against the passage of noise through the prior art grommet  10 . This can result in undesirable amounts of noise passing through the grommet To address this, the prior art grommet  10  also includes a service port plug  36  that is inserted in a second end  38  of the service port  22 . The service port plug  36  can be inserted into the service port  22  of the prior art grommet  10  during the initial installation of the prior art grommet  10  on the panel. If the need subsequently arises, the service port plug  36  can be removed to provide completely through access to the service port  22 . 
       FIGS. 2 ,  3 , and  4  illustrate a first embodiment of a grommet, indicated generally at  110 , in accordance with this invention. The grommet  110  includes a first tubular port  112  and a second tubular port  116  that are generally coaxial, although such is not required. The grommet  110  includes a body portion  114  from which the first tubular port  112  and the second tubular port  116  extend. The first tubular port  112  and the second tubular port  116  can accommodate a wiring harness (not shown) extending therethrough in a known manner. The second tubular port  116  has one or more annular ridges  118  formed on an inside surface thereof to restrain movement of the wire harness relative to the grommet  110  and to better accommodate wiring harnesses of differing diameters than would a smooth inside surface. A groove  120  is provided in the periphery of the grommet  110  to engage opposed sides of a panel  46  (see  FIG. 4 ) to retain the grommet  110  within a hole  44  extending through the panel  46 . 
     The grommet  110  has a service port  122  that functions as a passageway through the grommet  110  for wires and other articles that need to be added after the assembly of the vehicle. The service port  122  includes a first end  124  that is closed with a first cap  126 . The first cap  126  is formed integrally with a first wall  128  of the grommet  110 . In other words, the first cap  126  is formed from a single piece of material with the first wall  128 . However, it should be appreciated that the first cap  126  may, if desired, be made of other materials than the first wall  128 , may be created at a different time than the first wall  128 , and may be created by a process other than the process used to form the first wall  128 . When the need for the service port  122  arises, the first cap  126  is removed from the grommet  110  (such as by cutting) in order to provide access to the service port  122 . 
     The grommet  110  is illustrated as being a double-walled grommet that includes the first wall  128  and a second wall  130 . The double-walled configuration serves to reduce the amount of noise that can pass through the grommet  110  more than a single-walled grommet would. The first and second walls  128  and  130  of the grommet  10  define an internal port space  132 . The first tubular port  112  and the second tubular port  116  both communicate with the internal port space  132  and together define a passageway that extends from the first wall  128  to the second wall  130 , through which the wiring harness (not shown) can pass when it is installed. The service port  122  also extends from the first wall  128  to the second wall  130  of the grommet  110 . 
     The service port  122  also includes a second end  138  that is closed with a second cap  140 . The second cap  140  is formed integrally with the second wall  130  of the grommet  110 . In other words, the second cap  140  is formed from a single piece of material with the second wall  130 . However, it should be appreciated that the second cap  140  may, if desired, be made of other materials than the second wall  130 , may be created at a different time than the second wall  130 , and may be created by a process other than the process used to form the second wall  130 . When the need for the service port  122  arises, the second cap  140  is also removed from the grommet  110  (such as by cutting) in order to provide access to the service port  122 . Prior to that, however, the service port  122  is closed at both the first end  124  and the second end  1238 , as shown in  FIG. 3 . 
     The second cap  140  may be embodied as a locally-thin portion of the second wall  130 . Such a structure can serve to help an installer of an aftermarket accessory precisely identify the location of the second cap  140  so that the installer may cut the proper portion of the second wall  130 . This structure also serves to reduce the amount of material that is cut in order to use the service port  122 . It should be appreciated that the second cap  140  may be embodied as other than the locally-thin portion of the second wall  130  if so desired. For example, the second cap  140  may be embodied as a locally-thick area or may be identified by texture, text, or other visual indicator. Also, the second end  138  of the service port  122  may include an extended tube structure (not shown) that is similar to an extended tube structure  142  provided on the first end  124  of the service port  122 . 
     The grommet  110  includes a service port wall  134  that defines a portion of the service port  122 . The illustrated service port wall  134  does not extend from the first wall  128  to the second wall  130 , although such is contemplated by this invention. As a result, the illustrated service port  122  is not completely isolated from the internal port space  132 . Consequently, the internal port space  132  includes a portion of the service port  122 . This design aides in the manufacture of the grommet  110  because an internal tool or die may be used to define both the internal port space  132  and the service port  122 , thereby allowing the grommet  110  to be molded as one piece in a single-shot process, unlike the prior art grommet  10 . It should be appreciated, however, that the grommet  110  may be manufactured by processes other than single-shot molding if desired, and that the grommet  110  may be manufactured with the service port wall  134  extending completely from the first wall  128  to the second wall  130 . 
       FIG. 4  shows the grommet  110  in an installed position within the hole  44  that extends through the panel  46 . The grommet  110  is inserted so that an edge  48  of the hole  44  engages the groove  120 . A wiring harness  50  is inserted through the first tubular port  112 , the internal port space  132 , and the second tubular port  116 . If desired, the wiring harness  50  may have one or more layers of conventional tape  52  wound thereabout. The tape  52  assist in providing a seal between the wiring harness  50  and each of the first tubular port  112  and the second tubular port  116 . The tape  52  also serves to restrict movement of the wiring harness  50  relative to the grommet  110 . 
     When it is desired to pass an additional wire  54  or other article through the hole  44  formed through panel  46 , the service port  122  of the grommet  110  can be employed. To accomplish this, the first cap  126  and the second cap  140  are cut or otherwise removed from the grommet  110  to provide access through the hole  44 . If desired, the first cap  126  may be removed in its entirety from the grommet  110 . Alternatively, as shown in  FIG. 4 , a portion of the first cap  126  may be slit and deflected to open the first end  124  of the service port  122 . In either event, the second wire  54  can then be passed through the service port  122 , as also shown in  FIG. 4 . A sealant, such as room temperature vulcanization silicone  56 , may be used to completely re-seal the service port  122 . Additional tape  58  may be also used to attach the second wire  54  to the extended tube structure  142  at the first end  124  of the service port  122 . The second wire  54  may also be attached to the wiring harness  50  using one or more conventional zip-ties (not shown) in order to further restrict movement of the second wire  54  relative to the grommet  110 . 
       FIGS. 5 and 6  respectively illustrate second and third embodiments of the grommet  210  and  310 , respectively, of this invention. The second and third embodiments of the grommets  210  and  310  are similar to the grommet  110  in structure and operation, and like reference numbers are used to indicate similar structures. The second and third embodiments of the grommets  210  and  310  differ from the first embodiment of the grommet  110  in the relative orientation of their respective first tubular ports  212  and  312  and second tubular ports  216  and  316 . 
     The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.