Abstract:
A vehicle occupant protection system ( 10 ) includes a seat belt buckle ( 12 ) for receiving a seat belt tongue ( 16 ). A Hall effect device ( 62 ) is mounted on the seat belt buckle ( 12 ). The Hall effect device ( 62 ) has at least one electrical lead ( 72, 74 ). A magnet ( 68 ) is mounted on the seat belt buckle ( 12 ). The magnet ( 68 ) and the Hall effect device ( 62 ) are moveable relative to each other to first relative positions upon receipt of the seat belt tongue ( 16 ) in the seat belt buckle ( 12 ). The Hall effect device ( 62 ) provides a signal in response to the magnet ( 68 ) and the Hall effect device ( 62 ) being moved to the first relative positions. An electrical conductor ( 92, 94 ) has an electrical connection ( 110, 114 ) with the electrical lead ( 72, 74 ). The electrical connection ( 110, 114 ) is provided by melted portions ( 112, 116 ) of the electrical lead ( 72, 74 ) and the electrical conductor ( 92, 94 ) that are bonded together.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a vehicle occupant protection system. In particular, the present invention relates to means for providing an electrical connection between electrical components in a vehicle occupant protection system. 
     BACKGROUND OF THE INVENTION 
     It is known to provide a vehicle occupant protection system in a vehicle. One such vehicle occupant protection system is a seat belt for restraining a vehicle occupant. Such seat belts typically include seat belt webbing, a seat belt tongue on the webbing, and a seat belt buckle. The seat belt tongue is inserted in the buckle when the webbing has been placed about a vehicle occupant. A latch mechanism in the buckle interlocks with the seat belt tongue to secure the webbing about the occupant. The seat belt system may also include a sensor for indicating whether or not the seat belt tongue is locked in the buckle. Such a sensor may include electrically connected electrical components that provide such indication. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a vehicle occupant protection system that comprises a seat belt buckle for receiving a seat belt tongue. A Hall effect device is mounted on the seat belt buckle. The Hall effect device has at least one electrical lead. A magnet is mounted on the seat belt buckle. The magnet and the Hall effect device are moveable relative to each other to first relative positions upon receipt of the seat belt tongue in the seat belt buckle. The Hall effect device provides a signal in response to the magnet and the Hall effect device being moved to the first relative positions. An electrical conductor has an electrical connection with the electrical lead. The electrical connection is provided by melted portions of the electrical lead and the electrical conductor that are bonded together. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features of the present invention will become apparent to one skilled in the art to which the present invention relates upon reading the following description of the invention with reference to the accompanying drawings, in which: 
     FIG. 1 is an isometric view of a vehicle occupant protection system in accordance with the present invention; 
     FIG. 2 is a schematic sectional view of parts of the system of FIG. 1; 
     FIGS. 3 and 4 are views similar to FIG. 2 showing parts in different positions; 
     FIG. 5 is an exploded isometric view of parts of the system of FIG. 1; 
     FIG. 6 is an isometric view of the parts shown in FIG. 5, showing the parts in different positions; and 
     FIG. 7 is an isometric view of the parts of FIG. 6 showing the parts electrically connected. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     A vehicle occupant protection system  10  is shown in FIG.  1 . The system  10  includes a seat belt buckle  12 , seat belt webbing  14 , and a seat belt tongue  16  on the webbing  14 . The buckle  12  is anchored in a vehicle in a known manner, such as by a cable or anchor strap (not shown) extending within a cover  18 . A latch mechanism  20  (shown schematically in FIGS. 2-4) locks the seat belt tongue  16  in the buckle  12  when the seat belt tongue  16  is inserted into the buckle  12  through an opening  22  at the end of the buckle  12 . The seat belt tongue  16  is subsequently released from the buckle  12  upon depression of a pushbutton  24  adjacent to the opening  22 . 
     As shown in FIGS. 2-4, the buckle  12  includes a base  28  disposed within a housing  30 . The base  28  supports the latch mechanism  20  within the housing  30 , and defines a passage  32  that receives the seat belt tongue  16 . 
     The latch mechanism  20  may comprise any suitable structure capable of releasably interlocking with the seat belt tongue  16 . As shown by way of example in FIGS. 2-4, the latch mechanism  20  has a plurality of known parts including the pushbutton  24 , an ejector  40 , and a latch  42 . 
     The latch  42  is movable between a non-locking position (FIG. 2) and a locking position (FIG.  3 ). A latch spring  48  engages the latch  42  and biases it toward the passage  32 . The ejector  40  holds the latch  42  in the non-locking position against the bias of the latch spring  48 . 
     When the seat belt tongue  16  is inserted into the opening  22 , as indicated by the arrow shown in FIG. 2, it is moved into engagement with the ejector  40  in a notch  50  at the end of the ejector  40 . The seat belt tongue  16  is then moved inward against the ejector  40  so as to push the ejector  40  along the passage  32  from a forward position (FIG. 2) to a rearward position (FIG. 3) against the bias of an ejector spring  52 . 
     As the seat belt tongue  16  and the ejector  40  approach the positions of FIG. 3, an aperture  54  in the seat belt tongue  16  moves into alignment with the latch  42 . The latch spring  48  then moves the latch  42  downward to the locking position through the aperture  54  in the seat belt tongue  16  so that a first end portion  44  of the latch  42  blocks removal of the seat belt tongue  16  from the buckle  12 . 
     When the seat belt tongue  16  is to be released from the buckle  12 , the pushbutton  24  is moved from the position of FIG. 3 to the position of FIG. 4 against the bias of a pushbutton spring  56 . As illustrated in FIGS. 2-4, the pushbutton  24  includes a cam surface  25  that engages with flanges  45  located at the second end portion  46  of the latch  42  to move the latch  42  out of the aperture  54  in the seat belt tongue  16  against the bias of the latch spring  48 . The ejector spring  52  then moves the ejector  40  outward along the passage  32  toward the opening  22  to eject the seat belt tongue  16  from the buckle  12  as shown by the arrow in FIG.  4 . 
     The buckle  12  includes a sensor  58  that comprises electrical components, indicated generally at  60 , for detecting when the seat belt tongue  16  is locked in the buckle. The electrical components  60  are supported on the base  28 , within the housing  30 , by known means, such as an adhesive. As illustrated in FIGS. 2-4, the electrical components  60  include a Hall effect device  62 , a capacitor  64 , and a cable  66 . A magnet  68  is supported by, and movable with, the ejector  40 . The magnet  68  and the Hall effect device  62  are thus movable relative to each other. The magnet  68  is preferably insert molded or press fitted into the ejector  40 . 
     Referring now to FIGS. 5-7, the Hall effect device  62  comprises an integrated circuit  70  that is typically encapsulated in a material, such as a ceramic or polymeric material. The Hall effect device  62  includes first and second electrical leads  72  and  74  that extend from the integrated circuit  70 . The capacitor  64  includes a body portion  80  and first and second electrical leads  82  and  84  that extend from the body portion. The cable  66  comprises a pair of wires  90  that includes first and second electrical conductors  92  and  94  surrounded by insulating material  96 . The electrical leads  72 ,  74 ,  82 , and  84 , and the electrical conductors  92  and  94  are constructed of a metal, such as copper, tin, or an alloy thereof. 
     In accordance with the present invention, the electrical components  60 , i.e., the Hall effect device  62 , the capacitor  64 , and the cable  66 , are electrically connected by resistance welding. This eliminates the need for separate connecting means, such as solder, terminals, or other like separate connectors. Advantageously, this may also help to reduce the amount of time required to assemble the sensor  58 , the complexity of the manufacturing process used to assemble the sensor, and the cost of assembling the sensor. 
     In the illustrated embodiment, the first electrical leads  72  and  82  are electrically connected to the first electrical conductor  92 , and the second electrical leads  74  and  84  are electrically connected to the second electrical conductor  94 . The means by which the first electrical leads  72  and  82  are electrically connected to the first electrical conductor  92  is identical to the means by which the second electrical leads  74  and  84  are electrically connected to the second electrical conductor  94 . Therefore, only the means by which the first electrical leads  72  and  82  are electrically connected to the first electrical conductor  92  will be discussed in detail below. 
     In order electrically to connect the components  60  of the sensor  58  by resistance weld, the first electrical leads  72  and  82  are placed in physical contact with the first electrical conductor  92 . This is illustrated in FIG.  6 . Heat and pressure are then applied to the first electrical leads  72  and  82  and the first electrical conductor  92 . The heat and pressure may be applied simultaneously. The heat is generated by applying a voltage across the first electrical leads  72  and  82  and the first electrical conductor  92 . Portions  110  (FIG. 7) of the first electrical leads  72  and  82  and the first electrical conductor  92  are melted by the heat applied via the voltage. The melted portions  110  are combined together to form a bond, which creates an electrical connection, indicated generally at  112 , between the first electrical leads  72  and  82  and the first electrical conductor  92 . In an identical manner, an electrical connection, indicated generally at  114 , is created by melted portions  116  of the second electrical leads  74  and  84  and the second electrical conductor  94 . 
     Those skilled in the art will recognize that the sensor  58  may have alternative configurations. For example, the sensor  58  may omit the capacitor  64  and include only the Hall effect device  62  and the cable  66 . The sensor  58  may also include electrical components  60  other than, or in addition to, the Hall effect device  62 , capacitor  64  and cable  66 . Also, the electrical components  60  of the sensor  58  may be arranged in different positions relative to each other. 
     When the tongue  16  is not received in the buckle  12 , the latch  42  is in the non-locking position of FIG.  2 . When the latch  42  is in the non-locking position, the ejector  40 , and thus the magnet  68 , are spaced away from the sensor  58 . In the non-locking position, the magnet  68  creates a magnetic field of a first flux density that acts on the Hall effect device  62 . As a result, the Hall effect device  62  has a first output that corresponds to sensing the magnetic field of a first flux density when the buckle  12  is in the non-locking position. This indicates that the tongue  16  is not received in the buckle  12 . The first output is transmitted via the cable  66 . 
     When the tongue  16  is received in the buckle  12 , the latch  42  is in the locking position of FIG.  4 . When the latch  42  is in the locking position, the ejector  40  is spaced close to or adjacent the sensor  58 . The magnet  68  and the Hall effect device  62  are thus in first relative positions when the tongue  16  is received in the buckle  12 . Therefore, in the locking position, the magnet  68  creates a magnetic field of a second flux density that acts on the Hall effect device  62 . As a result, the Hall effect device  62  has a second output that corresponds to sensing the magnetic field of a second flux density, when the buckle  12  is in the non-locking position. This indicates that the tongue  16  has been received in the buckle  12 . The second output is transmitted via the cable  66 . 
     Thus, Hall effect device  62  senses a first flux density of the magnetic field when the latch  42  is in the non-locking position (FIG.  2 ). The Hall effect device  62  senses a second flux density of the magnetic field, different than the first flux density, when the latch  42  is in the locking position (FIG.  3 ). As a result, the Hall effect device  62  is switched from a first condition with a first output to a second, different condition with a correspondingly different output upon locking of the seat belt tongue  16  in the buckle  12  by the latch  42 . 
     Those skilled in the art will recognize that the seat belt buckle  12  may have alternative configurations in which different conditions are sensed by the sensor  58  in order to determine when the latch  42  is in the locking position. For example, the sensor  58  and the magnet  68  may be positioned such that the locking condition is sensed when the latch  42  is in the position of FIG. 3 or when the seat belt tongue  16  is in the position of FIG.  3 . Also, the sensor  58  and/or the magnet  68  may be connected to different parts of the buckle  12 . For example, sensor  58  and/or the magnet  68  may be connected to the housing  30 , latch  42 , or ejector  40 . 
     The sensor  58  can be used to alert a vehicle occupant to the locked or unlocked condition of the seat belt tongue  16  and buckle  12 . For example, an audible alarm or a lamp on the vehicle instrument panel could be activated in response to the output of the Hall effect device  62  to alert a vehicle occupant if the seat belt tongue  16  is not locked in the buckle  12 . 
     The sensor  58  can also be used to control one or more vehicle occupant protection devices. For example, the sensor  58  can be included in a deployment system with an inflatable vehicle occupant protection device. The sensor  58  can be used to control the inflation of the protection device depending upon the buckled or unbuckled condition of the seat belt. The inflatable device can be any one of several different types of inflatable vehicle occupant protection devices known in the art. Such inflatable devices include air bags, inflatable seat belts, inflatable knee bolsters, inflatable head liners, and knee bolsters operated by air bags. 
     From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. For example, although the present invention has been described as providing an electrical connection for electrical components in a seat belt buckle, the present invention may be used to provide an electrical connection for electrical components in other vehicle occupant protection systems. Examples of such alternative uses may be in sensors, switches, or actuators in seat belt retractors or pretensioners. Other alternative uses may be in vehicle seat position or occupant weight sensors. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.