Abstract:
An enclosed contact horn mechanism includes: a pin having a first end and a second end; a base plate located near the first end; and a device located between the first end and the base plate; the device, the first end, and the base plate creating an enclosed contact area, wherein the device is movable so that the base plate may contact the first end.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application Ser. No. 60/368,511 filed Mar. 29, 2002, the contents of which are incorporated herein by reference thereto. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to horn contact mechanisms and more particularly the present disclosure relates to horn contact mechanisms for use with driver&#39;s side air bag modules. 
     BACKGROUND 
     Vehicles are supplied with driver&#39;s side airbag modules; generally the driver&#39;s side airbag module is located in the center of the steering wheel. This is also the same location where a horn-activating switch has traditionally been mounted. Thus, when driver&#39;s side airbags were first introduced, the horn-activating switch was moved from the center to another location on the steering wheel to make room for the airbag. The horn-activating switches were often mounted on the steering wheel spokes or rim. However, many drivers preferred that the horn-activating switch be located at the center of the steering wheel. 
     Eventually, the horn-activating switch was adapted for mounting on the underside of the airbag module cover between the inflatable airbag and the cover of the module. This type of switch allowed the horn-activating switch to be placed in its traditional position. Such horn-activating switches react to a user-applied force to the cover in an effort to sound the horn. For example, a floating horn system where the entire airbag moves as force is applied to actuate the horn. However, such existing horn mechanisms contain contact points that are exposed to environmental conditions. These contact points are used to activate the horn by completing an electrical circuit. These exposed contact points can corrode when exposed to environmental conditions. In turn, this corrosion leads to the inability to complete the electrical circuit and blow the horn. 
     In addition, positive stack up tolerances between horn mechanism components can lead to greater distances of module travel before horn contact is made. The distance between the contact points of the horn mechanism can become greater than the gap between the driver airbag module and the steering wheel. As a result, there could be “no-blow” condition of the horn. Also, the greater distance between contact points can lead to increased horn efforts. Negative stack up tolerances between horn mechanism components can lead to less distances of module travel before horn contact is made. This can lead to inadvertent horn blows, constant horn actuation, and reduced horn efforts. 
     SUMMARY 
     The above discussed and other drawbacks and deficiencies are overcome or alleviated by an enclosed contact horn mechanism. An enclosed contact horn mechanism comprising: a pin having a first end and a second end; a base plate located near the first end; and a device located between the first end and the base plate; the device, the first end, and the base plate creating an enclosed contact area, wherein the device is movable so that the base plate may contact the first end. 
     An enclosed contact horn mechanism comprising: a pin having a first end and a second end, the second end being configured for securing an airbag module to a portion of a steering wheel. The module also has a base plate located near the first end and a device located between the first end of the pin and the base plate. The device, the first end, and the base plate creating an enclosed contact area, wherein the device is configured so that the base plate may contact the first end. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a mounting side of a portion of a driver&#39;s side air bag module with a horn contact mechanism; 
     FIG. 2 is another perspective view of a portion of a DAB illustrated in FIG. 1; 
     FIGS. 3A-3B illustrate operational aspects of the horn contact mechanism of the present disclosure along lines  3 — 3  of FIG. 1; 
     FIG. 4 is perspective view of a portion driver&#39;s side air bag module secured to an armature of a steering wheel; 
     FIG. 5 is a block diagram showing a driver&#39;s side driver air bag module connected to a power source and a horn; 
     FIG. 6 is a top plan view of a steering wheel with a driver&#39;s side air bag module; 
     FIG. 7 is a view along lines  7 — 7  of FIG. 6; 
     FIGS. 8A-8E illustrate a backing plate constructed in accordance with the present disclosure; 
     FIGS. 9A-9D illustrate a base plate constructed in accordance with the present disclosure; 
     FIGS. 10A-10C illustrate an insulator constructed in accordance with the present disclosure; 
     FIG. 10D is a view along lines  10 D- 10 D of FIG. 10C; 
     FIG. 10E is a view along lines  10 E- 10 E of FIG. 10C; 
     FIGS. 11A-11B illustrate a contact pin constructed in accordance with the present disclosure; 
     FIGS. 12A-12B illustrate a washer constructed in accordance with the present disclosure; 
     FIGS. 13A-13B illustrate a coil constructed in accordance with the present disclosure; 
     FIG. 14 is a cross-sectional view of an alternative embodiment of the present disclosure; and 
     FIG. 15 is a cross-sectional view of another alternative embodiment of the present disclosure. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, a portion of a driver&#39;s side air bag module (module)  10  having a horn contact mechanism  11  is illustrated. Module  10  has among other elements a backing plate  12  (See also FIGS. 8A-8E) and a base plate  14  (See also FIGS.  9 A- 9 D). Both backing plate  12  and base plate  14  have a large center opening  16  and smaller connection openings  18  surrounding center opening  16 . Connection openings  18  are used to secure an inflator (not shown) to module  10 . A portion of the inflator is received within opening  16 . Backing plate  12  has four raised areas  20  located at each corner  22  of backing plate  12 . Raised areas  20  define an area  21  for receiving a portion of the horn contact mechanism. Area  21  is sufficiently large enough to house portions of the horn contact mechanism which will be discussed in more detailed below. Each raised area  20  has a pin opening  24  with three grooves  26  or areas located around the periphery of pin opening  24 . Of course, the number and configuration of grooves or openings  26  may vary. A pin  30  extends through pin opening  24 . Pin  30  is made of a material that can conduct electricity and is preferably steel. Pin  30  serves a dual purpose of securing the driver&#39;s side airbag (DAB) to the steering wheel and providing a contact portion of horn contact mechanism. In an exemplary embodiment Pin  30  remains fixedly secured to an armature of a steering column while driver&#39;s side air bag module  10  moves upon an actuation force provided by a vehicle operator. The movement of driver&#39;s side air bag module  10  causes a portion of the pin to become in contact with another portion of the driver&#39;s side air bag module in order to complete the electrical circuit of the horn switch. 
     An insulator  32  (See also FIGS.  10 A- 10 E), which is preferably made from plastic or other nonconductive material, is disposed about a base  34  (see FIG. 3) of pin  30 . Alternatively, insulator  32  is positioned within area  21  of raised area  20 . Insulator  32  has three features or bumps  36  that fit within grooves or openings  26 . Of course, the number of features  36  may vary along with the number of openings  26 . A coil  40  (See also FIGS. 13A-13B) surrounds pin  30  and fits over insulator  32 . Coil  40  is configured to provide a biasing force between insulator  32  and a portion of the steering wheel armature  80  (See FIGS. 3A,  3 B,  4  and  7 ) that pin  30  is secured to. Coil  40  may also be connected directly to insulator  32 . A locking spring  42  secures four of pins  30  to a portion of an armature  80  (See FIGS. 3A-3B and  4 ). Locking spring  42  is configured to make contact with grooves located on a portion of pin  30 . Accordingly, locking pin  42  secures pins  30  and driver&#39;s side air bag module  10  to an armature  80  of a steering wheel. 
     Referring now to FIG. 2, base plate  14  has a plurality of slots  50  located at each corner  22  of base plate  14 . Slots  50  line up under raised areas  20  (see FIG. 1) of backing plate  12  when backing plate  12  and base plate  14  are assembled. In particular, there are three slots  50  located at each corner  22  and each of the three slots  50  aligns with each groove  26  in pin opening  24  (see FIG.  1 ). Slots  50  are shaped so that there is a first end  51  that is larger than a second end  52  of each slot  50 . 
     Referring to FIG. 3, a side view of pin  30  assembled with backing plate  12  and base plate  14  is illustrated. A sealing means or device, such as a urethane washer  60 , having a central opening is located in a cavity  61  between a first end  62  of pin  30  and base plate  14 . First end  62  has a flange  64  that is wider than width of a main body  66  of pin  30 . Main body  66  and insulator  32  are configured to allow insulator  32  to move with respect to pin  30  as a force is being applied to the air bag module. First end  62  also has an extension or contact point  70 , which protrudes outwardly from a portion of first end  62 . Extension  70  protrudes a distance that is greater than the thickness of a side  68  of washer  60 . Thus, if washer  60  is flattened against first end  62 , extension  70  extends through the central opening of washer  60 . 
     Pin  30  and washer  60  are inserted into insulator  32  prior to securement of backing plate  12  to base plate  14 . Insulator  32  fits over flange  64  and extends up along main body  66  of pin  30 . Insulator  32  has three features or hooked ends  72  (only one shown) that depend away from insulator  32  and extend past washer  60  when insulator  32  is assembled with pin  30  and washer  60 . Hooked ends  72  are configured to be inserted into and through first end  51  of slots  50  (see FIG. 2) of base plate  14 . In order to secure insulator  32  to base plate  14  insulator  32  is then rotated so that hooked ends  72  slide in slots  50  so that hooked ends  72  are located at second end  52  of slots  50  (see FIG.  2 ). This movement of insulator  32  secures pin  30 , washer  60 , and insulator  32  to base plate  14 . In addition, and through the securement of insulator  32  and a device such as washer  60  cavity  61  is an enclosed contact area, which is located between first end  62  of pin  30  and base plate  14 . The enclosed contact area is completely enclosed by washer  60 , pin  30 , and base plate  14 . Thus, extension  70 , which in the position illustrated in FIG. 3B, contacts base plate  14  and is located within the enclosed contact area and is not exposed to the elements. 
     Backing plate  12  is then assembled so that pins  30  are inserted through pin openings  24  located at raised areas  20  (also see FIG.  1 ). Raised areas  20  are configured so that backing plate  12  is seated against insulator  32 . As such, a portion of both pin  30  and insulator  32  are located within pin opening  24 . Pin opening  24  is smaller than flange  64  of pin. Backing plate  12  also helps to secure insulators  32  to base plate  14 . This also provides additional strength to insulators  32 . Coil  40  is then inserted over pin  30  and insulator  32 . 
     Referring again to FIG. 1, bumps or features  36  are configured to fit within grooves or openings  26 , which holds insulator  32  in place so that insulator  32  does not rotate and allow hooked ends  72  to release from slots  50 . Backing plate  12  and base plate  14  are secured to each other when an inflator (not shown) of the driver&#39;s side air bag module is secured to the backing plate  12  and base  14 , which occurs at small connection openings  18 . 
     Referring to FIGS. 3 and 4, pins  30  are attached to a steering wheel armature (armature)  80  through locking spring  42 . Locking spring  42  fits into a notch  82  at a second end  84  of pin  30 . Locking spring  42  has ends  86  that are located under armature  80 . In addition, locking spring  42  also hooks under an extension  88  of armature  80 . Extension  88  is located approximately half way between two pins  30  (see FIG.  4 ). As such, locking spring  42  secures pins  30  to armature  80 . Armature  80  contains power leads for the horn system, initiation of the air bag, and for power controls on the steering wheel. 
     Referring now to FIG. 5, base plate  14  is electrically connected to a power source  90  through a lead so that base plate  14  is “hot” or provided with an electrical current. In addition, pin  30  is electrically connected to a horn  92  through armature  80  or other connection means such as an electrical lead. Therefore, the horn circuit is open when the pin  30  is in the position illustrated in FIG.  3 A. This is provided by the insulating qualities of insulator  32  and the air gap between extension  70  and base plate  14 . Alternatively, base plate  14  is electrically grounded and contact between pin  30  and base plate  14  is used to complete the horn activation circuit. 
     Referring to FIGS. 6 and 7, module  10  is located at a steering wheel  100 . Module  10  is located within an inside area  102  of steering wheel  100 . A deployable cover  104  as is known in the art is located over module  10 . 
     Referring now to FIGS. 1-7, horn contact mechanism  11  operates as follows. A driver pushes on cover  104  of steering wheel  100 . As the driver pushes on cover  104 , a force is applied to module  10  in the direction of arrow  106 . As a result, base plate  14  and backing plate  12  move and compress coils  40  located at each pin  30 . As base plate  14  and backing plate  12  move, insulator  32  also moves with base plate  14 , which causes base plate  14  to compress washer  60 . Washer  60  flattens so that extension  70  comes into contact with base plate  14 . When extension  70  contacts base plate  14 , the electrical circuit for horn  92  is complete and horn  92  is activated. Horn  92  is grounded at armature  80 . When the driver stops pressing on the steering wheel, coil  40  forces module  10  back to its starting position and extension  70  is no longer in contact with base plate  14  and horn  92  is no longer activated. 
     Although four contact mechanisms are shown in the aforementioned Figures it is contemplated that the driver&#39;s side air bag module can be constructed with more or less than four mechanisms and not all pins need to be configured as a horn contact mechanism. 
     Alternatively, washer  60  could be removed and module  10  would operate in the same manner as described above. In that embodiment, extension  70  is still located in the enclosed contact area, and extension  70  is completely enclosed by insulator  32 , pin  30 , and base plate  14 . In either embodiment, extension  70  remains fully enclosed. 
     Referring to FIG. 14, an alternative embodiment for enclosed contact horn mechanism  11  is illustrated. This embodiment is similar to the one described in FIGS. 1-7; however, air bag module  10  is constructed without backing plate  12 . 
     Referring to FIG. 15, an alternative embodiment for enclosed contact horn mechanism  11  is illustrated. This embodiment is also similar to the one described in FIGS. 1-7. Extension  70  extends from base plate  14  into cavity  61 , which is an enclosed contact area in which a first end  112  of extension contacts pin  30 . Extension  70  may be part of base plate  14 , or may be connected to base plate by welding or other such manner known in the art. Insulator  32  surrounds extension  70 , except at a first end  112 . This embodiment operates as follows. A driver exerts a force on base plate  14 , which moves and compresses coils  40  located at each pin  30 . As base plate  14  moves, insulator  32  and extension  70  also move with base plate  14 , which causes first end  112  of extension  70  to come into contact with pin  30 . When extension  70  contacts pin  30 , the electrical circuit for horn  92  (see FIG. 5) is complete and horn  92  is activated. Horn  92  is grounded at armature  80 . When the driver stops pressing on the steering wheel, coil  40  forces base plate  14  back to its starting position. Extension  70  is no longer in contact with base plate  14  and horn  92  is no longer activated. 
     Module  10  having an enclosed contact horn mechanism  11  provides for cavity  61 , which is also the enclosed contact area, and provides that the contact area for horn  92 , which occurs at extensions  70 , is not susceptible to environmental conditions. Consequently, extensions  70  will not corrode, which provides for improved horn blow activation. In addition, module  10  provides for all contact surfaces to occur within one assembly located at module  10 . The design also provides in-line contact points and reduces the amount of stack tolerances. As such, module  10  is also less susceptible to inadvertent horn actuation. 
     While this invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.