Patent Publication Number: US-2007117433-A1

Title: Power supply circuit for removable automotive interior systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      Not Applicable  
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not Applicable  
     REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX  
      Not Applicable  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates in general to a vehicle interior power supply connections for interior trim members of a vehicle, and more specifically, to a disconnectable power supply circuit for a detachable interior trim member of a vehicle such as a seat.  
      2. Description of the Related Art  
      Vehicle interior systems such as passenger seats are removable from a vehicle and/or stowable in the vehicle. Vehicle seats which include electrical load devices such as heating elements or motors for moving portions of the seats require power be supplied to the vehicle seat through an electric connection. Typically the floor area is the only suitable location for making the electrical connection between a power supply connector and a releasable connector incorporated within the vehicle seat. For vehicle seats that are removable, stowable, or pivotable to a tilt forward position, a mating portion of the electrical interconnection must also be detachable to allow the vehicle seat to be removed, stowed, or pivoted fully forward.  
      In an electrical connection system which automatically connects and disconnects the mating connectors when the vehicle seat is removed from its position, an exposed power supply connector is present when the seat is removed. The exposed electrical contact is susceptible to a short circuit caused by the electrical contacts coming into contact with a foreign object or by a person, in addition to damage caused by impacts to the contact from the person or object. Furthermore, being that the electrical connection to a vehicle seat is typically made at the floor level, an exposed connector may be susceptible to debris and liquids spilled on the floor which may lead to the corrosion or damage to the electrical contact.  
     BRIEF SUMMARY OF THE INVENTION  
      This invention has the advantage of determining whether an electrical connection is made between two connectors of an electrical supply circuit for supplying power to an electric device within an interior trim member of a vehicle. The electrical supply circuit disconnects power to the power supply connector when the system impedance is outside of a predetermined range that indicates that the connectors are disconnected or that the electrical supply circuit has a short circuit fault.  
      In one aspect of the present invention, an electrical power supply system is provided that includes a vehicle interior trim member selectably mountable to a vehicle interior. The vehicle interior trim member includes an electrical load device and a releasable connector for receiving electrical energy for powering the electrical load device. The releasable connector includes a high impedance element. A power supply connector is electrically coupled to a power supply and is releasably attachable to the releasable connector for supplying electrical energy from the power supply to the electrical load device. A switching circuit measures an impedance of the electrical supply system and selectively energizes the power supply connector. The releasable connector is connected to the power supply connector when the vehicle interior trim member is attached to the vehicle and is disconnected from the releasable connector when the vehicle interior trim member is detached from the vehicle. The switching circuit disconnects power to the power supply connector when the impedance is outside of a predetermined range. The switching circuit provides power to the power supply connector when the impedance is within the predetermined range.  
      In one aspect of the present invention, an electrical power supply system is provided that includes a vehicle interior trim member selectably mountable to a vehicle interior. The vehicle interior trim member includes an electrical load device and a releasable connector for receiving electrical energy for powering the electrical load device. The releasable connector includes a high impedance element having an impedance within a predetermined range less than an open circuit impedance. A power supply connector is fixedly mounted to the vehicle interior and adapted to be electrically coupled to a power supply. The power supply connector is also releasably attachable to the releasable connector for supplying electrical energy from the power supply to the electrical load device. A switching circuit measures an impedance across the power supply connector and selectively energizes the power supply connector in response to the measured impedance. The releasable connector is connected to the power supply connector when the vehicle interior trim member is selectively attached to the vehicle and is disconnected from the releasable connector when the vehicle interior trim member is selectively detached from the vehicle. The switching circuit disconnects power from the power supply connector when the measured impedance is outside of the predetermined range. The switching circuit connects power to the power supply connector when the measured impedance is within the predetermined range.  
      Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a view of a interior compartment of a vehicle illustrating detachable interior trim members according to a preferred embodiment of the present invention.  
       FIG. 2  is a perspective view of the power supply connector according to a first preferred embodiment of the present invention.  
       FIG. 3  is a perspective view of the male terminal contacts of the power supply connector according to a first preferred embodiment of the present invention.  
       FIG. 4   a  and  4   b  are perspective views of the releasable connector according to a preferred embodiment of the present invention.  
       FIG. 5  is an illustration of the connection of the power supply connector and the releasable connection preferred embodiment of the present invention.  
       FIG. 6  is an electrical schematic of the electrical supply system circuit according to a preferred embodiment of the present invention.  
       FIG. 7  illustrates a graph of a predetermined impedance range for determining a power supply state according to a preferred embodiment of the present invention.  
       FIG. 8  illustrates a switching circuit cycle chart in relation to the measured system impedance.  
       FIG. 9  is a method for powering on and off the power supply connector according to a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring now to the drawings, there is illustrated in  FIG. 1  an interior of a vehicle shown generally at  10 . The interior of the vehicle  10  includes a driver&#39;s seat  12 , a front passenger&#39;s seat  14 , a rear passenger seat  16 , and a front center console  18  that are mounted to a vehicle floor shown generally at  20 .  
      The rear passenger seat  16  includes a latch mechanism  22  disposed on a bottom corner of the rear passenger seat  16 . The latch mechanism  22  includes a latch  24  and latch release lever  26 . The latch mechanism  22  is typically spring-loaded to allow the latch to move into position for engaging a catch  28  mounted in the vehicle floor  20 . The latch  24  is unlatched for allowing the rear passenger seat to be moved. For example, the rear passenger seat  16  may be pivoted forward to allow a person access to the rear of the rear passenger seat  16 , stowing the rear vehicle seat  16  in a stowable compartment (not shown), or removing the rear passenger seat  16  from the vehicle interior.  
      The rear passenger seat  16  further includes an electrical load device  30 , such as a vehicle seat warmer. The electrical load device  30  may further other types of electrical load devices such as a seat motor for adjusting a backrest or lumbar. A releasable connector  32  is mounted on a bottom portion of the vehicle seat  16  for receiving and supplying power to the electrical load device  30  and is moveable with the rear passenger seat  16  as the seat is moved.  
      The vehicle floor  20  includes a power supply connector  34  for providing power to the releasable connector  32  when electrically coupled. The power supply connector  34  is fixedly mounted in the vehicle floor  20 . Preferably, the power supply connector  34  is recessed below the floor  20  such as in a pilot hole  36 . Recessing the power supply connector  34  below the floor  20  prevents the power supply connector  34  from being damaged by impacts.  
      The releasable connector  32  of the rear vehicle seat  16  is in electrical contact with the power supply connector  34  when rear vehicle seat  16  is in a latched position. As the rear passenger seat  16  is moved to the latch position, the releasable connector  32  extends into the pilot hole  36  and mates the power supply connector  34  recessed below the floor  20 . This not only prevents the connection of the power supply connector  34  and the releasable connector  32  from being damaged by contact but also prevents a person or object from contacting the electrical connection when energized.  
       FIG. 1  further shows an interior trim member such as the front center console  18  that is detachable from the vehicle interior compartment  10 . The front center console  18  may include an electrical load device such as a multimedia device (i.e., DVD player for viewing movies or a CD magazine rack for playing audio). The front center console  18  or a portion thereof may be detachable to allow the electrical load device to be removed from the vehicle. The front center console  18  includes an electrical connection, shown generally at  38 , that is similar to the electrical connection described above. When the front center console  18  is mounted to the floor  20  or other adjacent structure, an electrical connection is made between the two mating connectors. When the front center console  18  is detached from the floor  20  or other adjacent structure, the center console power supply connector is recessed within the floor  20  to avoid contact or interference with any exterior objects or passengers.  
       FIG. 2  illustrates a perspective view of the power supply connector  34 . The power supply connector  34  includes a first male terminal contact  40  and a second male terminal contact  42  for supplying electrical energy from a power supply device (e.g., vehicle battery) to a female mating connector. The power supply connector  34  includes a circular base portion  44  integrally formed with a guide post  46 .  
      Referring to both  FIGS. 2 and 3 , the first male terminal contact  40  includes a longitudinal section  48  that is integrally formed to a ring portion  50  that is open ended. The ring portion  50  is retained about the circumference of the post  46 . The post  46  may include a notched portion in which the ring portion  50  s inserted therein. Alternatively, the open ended ring portion  50  may be insert-molded as part of the post  46 . The longitudinal section  48  extends axially along the post  46  and through the circular base portion  44 . An end  52  of the longitudinal section  48  protrudes from a bottom portion the circular base portion  44  for connecting to a wire or harness (not shown) for receiving voltage from the designated power source.  
      The second male terminal contact  42  includes a longitudinal section  58  that is integrally formed to a ring portion  60  that is open ended. The ring portion  60  is retained about the circumference of the post  46  and is spaced axially in relation to the first ring portion  50 . The post  46  may include a notched portion in which the ring portion  60  is inserted therein. Alternatively, the ring portion  60  may be insert-molded as part of the post  46 . The longitudinal section  58  extends axially along the post  46  and through the circular base portion  44 . An end  62  of the longitudinal section  58  protrudes from the bottom portion of the circular base portion  44  for connecting to a wire or harness (not shown) for receiving voltage from a designated power source.  
      An open end  64  of the ring portion  50  provides an axial passage for allowing the longitudinal section  58  of the second male terminal contact  42  to extend past the open ended ring portion  50  without contacting and shorting the first male terminal contact  40  to the second male terminal contact  42 .  
       FIGS. 4   a  and  4   b  illustrate perspective views of the releasable connector  32 . The releasable connector  32  includes a main body  66  made from a nonconductive material. The main body  66  includes an inner bore  67  that extends axially through the main body  66 . The releasable connector  32  includes a first female terminal contact  70  that includes a conductive circular member  74  that in electrical contact with a conductive longitudinal member  78 . The releasable connector  32  further includes a second female terminal contact  72  which includes a conductive circular member  80  in electrical contact with a conductive longitudinal member  84 . The first female terminal contact  70  and second female terminal contact  72  are insert-molded. into the main body  66  and are exposed to the inner bore  67 . A circular seal  86  is also insert molded within the main body  66  and exposed to the inner bore  67 .  
       FIG. 5  illustrates the connection between the. releasable connector  32  and the power supply connector  34 . The first female terminal contact  70  includes the conductive circular member  74  which is a spring-like member that has radial retention properties for contacting the post  46  when. inserted within the conductive circular member  74 . The conductive circular member  74  and the conductive longitudinal member  78  may be integrally formed or may be held in electrical contact with one another by the main body  66 . The conductive longitudinal member  78  extends axially within the main body  66 . The conductive longitudinal member  78  protrudes through an end surface  82  for electrically coupling to a respective conduit for supplying voltage to the electrical load device  30  within the interior trim member.  
      The second female terminal contact  72  includes the conductive circular member  80  which is a spring-like member that has retention properties when the post  46  is inserted within the conductive circular member  80 . The conductive circular member  80  and the conductive longitudinal member  84  may be integrally formed or may be held in contact with one another by the main body  66 . The conductive longitudinal member  84  extends axially within the main body  66 . The conductive longitudinal member  84  protrudes through an end surface  82  for electrically coupling to a respective conduit for supplying voltage to the electrical load device within the interior trim member.  
      The seal  86  is seated within the main body  66  and is exposed to the inner bore  67  near an end portion  88  of the releasable connector  32  for preventing debris from entering the end portion  88  when the power supply connector  30  and the releasable connector  32  are coupled.  
      The post  46  of the power supply connector  30  positioned on a bottom portion of the rear passenger seat  16  is seated within the bore  67  of the releasable connector  32  when the rear passenger seat  16  is in a secured position to the floor  20 . When the post  46  enters the bore  67  from the end portion  88 , the post  46  as well as the first and second male terminal contacts  40  and  42  makes contact with the seal  86  as the post  46  moves through the bore  67 . As the first and second terminal male contacts  40  and  42  slidingly contact the seal  86 , fluid and debris are wiped from each respective contact. As the end portion  88  of the power supply connector  34  bottoms out against a top surface  90  of the circular base portion  44 , the first male terminal contact  42  is in electrical contact with the first female terminal contact  70  and the second male terminal contact  42  is in electrical contact with the second female terminal contact  72 . Both conductive circular members  74  and  80  exert and inward radial force against the ring portions  50  and  60  for maintaining an electrical connection when the electrical load device  30  is activated. Power is provided to the electrical load device  30  within the rear passenger seat  16  via the mating electrical contacts.  
       FIG. 6  illustrates a schematic of an electrical supply system  91 . The electrical supply system  91  includes a power supply circuit  92  and a releasable supply circuit  94 . The power supply circuit  92  includes a power supply source  95 , a switching circuit  96 , and the power supply connector  34 . The power supply source  95  may be an energy storage device such as a battery or an energy generating device such as an alternator. In the preferred embodiment, the power source  95  is electrically connected between the switching circuit  96  and the power supply connector  34 . The switching circuit  96  measures an impedance as seen by the switching circuit  96 . The switching circuit  96  includes a re-settable controlled switch  97 , solid state fuse, or other device which be used connect or disconnect power between the power source  95  and the power supply connector  34 . Alternatively the controlled switch  97  or like device may be disposed in a power distribution box (not shown).  
      The releasable supply circuit  94  includes the releasable connector  32 , a device switch  98 , and the electrical load device  30 . The releasable connector  32  is re-connectable with the power supply connector  34  for receiving power from the power supply circuit  92 . The device switch  98  is a power on-off switch which is used to make the electrical connection within the releasable supply circuit  92  for providing electrical energy to the electrical load device  30 . The releasable connector  32  also includes a high impedance resistor or other high impedance element  99 . This assists in differentiating the impedance of the electrical supply system circuit  91  when the power supply connector  34  and the releasable connector  32  are disconnected in comparison to when the respective connectors are connected but the device switch  97  is open.  
       FIG. 7  illustrates a range of measured impedances which is used to determine whether power is to be connected to the power supply connector. When the measured impedance value is within a predetermined range, the switching circuit  96  provides power to the power supply connector  34 . For measured impedances that are outside of the predetermined range, the switching circuit  96  disconnects power from the power supply connector  34 .  
      The following conditions illustrate occurrences when power is connected or disconnected from the power supply connector  32 . A first circuit condition includes the power supply connector  34  being disconnected from the releasable connector  32 . This results in an open circuit condition and the total impedance as measured by the switching circuit  96  is an infinite impedance. The infinite impedance is outside of a predetermined range, and as a result, power is disconnected to the power supply connector  34 .  
      A second circuit condition occurs when the power supply connector  34  is connected to the releasable connector  32  and the device switch  98  is closed. The total impedance as measured by the switching circuit  96  includes the impedance of the power supply circuit  92  and the impedance of the releasable supply circuit  94  (e.g., the load) in parallel with element  99 . The measured impedance is substantially equal to the load impedance. The predetermined range is set-up to include this impedance level and the switching circuit  96  connects power to the power supply connector  34 .  
      A third circuit condition occurs when the power supply connector  34  is connected to the releasable connector  32  and the switch device  98  is open. The impedance of the electrical load device  30  is not sensed by the switching circuit  96 . The measured impedance includes the impedance of the power supply circuit  92  in series with the high impedance element  99 . The measured impedance is within the predetermined range and power is connected to the power supply connector. The differentiating factor is the inclusion of the high impedance element  99 . In contrast to a circuit that does not utilize the high impedance element  99 , the measured impedance as seen by the switching circuit  96  where the respective connectors are connected but the device switch  98  is open would have substantially the same impedance as when the respective connectors are disconnected.  
      A fourth circuit condition includes a short circuit occurring in the electrical supply circuit  91  while the power supply connector  34  and the releasable connector  32  are connected. The measured impedance by the switching circuit  96  would not include the load of the electrical load device  30  nor the high impedance element  99 . The measure impedance (i.e., with the system circuit shorted) would have a low impedance value that is not within the predetermined range. Power to the power supply connector  32  is disconnected.  
       FIG. 8  illustrates a switching circuit cycle between the power on/off (i.e., power connected/disconnected to the power supply connector) and the measured impedance. Point A illustrates a condition when the circuit is disconnected and there is an open circuit of substantially infinite impedance. The power is disconnected from flowing through the power supply connector during this condition. Point B illustrates the respective connectors connected and the device switch closed. Power flows through the power supply circuit and to the releasable system connector. Point C illustrates the unmating of the connectors. The measured impedance of the electrical supply system is at infinite impedance. Power flowing through the power supply circuit is disconnected. Point D illustrates a condition where the connectors are mated but the device switch is open. Power is provided to the power supply connector. Point E illustrates a short circuit condition. During the short circuit, the measured impedance will not include the load or the high impedance element. The impedance is low and power flowing to the power supply connector is thereby disconnected.  
       FIG. 9  illustrates a method for powering on and off the power supply connector in response to the measured impedance. In step  100 , the vehicle interior trim member is in either the latched or unlatched position. In step  101 , the impedance of the electrical supply system is measured. In step  102 , a determination is made as to whether the measured impedance is within a predetermined range. If the determination is made that the measured impedance is within a predetermined range, then power to the power supply connector is connected in step  103 . If the measured impedance was not within a predetermined range, then power to the power supply connector is disconnected in step  104 .  
      In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. 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.