Abstract:
A seat folding apparatus is provided with a passive Rf frequency link that requires that a person be within a certain limited distance from the vehicle to operate the seat folding mechanism. A foreign object detection system, such as a plurality of weight sensors, is provided in the seat to detect foreign objects on the seat.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic control system for a vehicle seat that is convertible between different positions such as a seat position and a load floor position. 
     2. Background Art 
     A wide variety of vehicle seating arrangements are available for vans, minivans, and sport utility vehicles (“SUVs”). Vehicle seating systems may add versatility to vehicles that is derived from the ability to provide different seating configurations. Vehicle seating systems may include seats that are used in a conventional seating configuration or may be converted to provide a full or a partial load floor for hauling cargo. Some minivans are provided with removable seats that are releasably connected to anchoring devices secured to the vehicle compartment pan. More recently, seats are available that may fold into recesses in compartment pans to provide a continuous load floor without the need to remove the seats from the vehicle. Some seats are foldable into a console position with the seat back being folded forward over the seat base. 
     Most vehicle seating systems are manual and require a person to release a lever and reposition various portions of the seat to convert the seat to different modes. A recent innovation is the introduction of power folding seats such as that disclosed in U.S. Pat. No. 6,540,295 that is assigned to the assignee of this application. The power folding seat disclosed in this patent includes an electric motor that rotates the seat back between an upright, slanted seat back position and a generally horizontal load floor position. The motor used to fold the seat may be provided with a voltage regulator that monitors the voltage across the motor that may increase if a foreign object is encountered by the seat as it is moved by the motor. If a foreign object is contacted by the seat, the seat folding mechanism may attempt to continue the folding operation until the motor stalls. The motor stall condition is detected by the voltage regulator that interrupts operation of the motor. Folding a seat into a foreign object may damage the seat or the object. 
     The &#39;295 patent also discloses the concept of operating the power folding seat upon receipt of an RF signal from an RF transmitter such as a key FOB. The &#39;295 patent also discloses that location sensors may be provided upon various parts of the seat structure to be sure that the movable panels of the seat system are in the proper position for a given folding operation. 
     The seat system disclosed in the &#39;295 patent is currently in production as the 2005 Cadillac SRX® sport utility vehicle. As currently produced, the seat has a manually actuated switch that must be held in to complete the folding operation. If the operator releases the switch during the folding operation, the seat folding operation is immediately interrupted to prevent damage to the seat folding mechanism or objects located on or around the seat. Some customers have indicated the desire to provide a power folding seat that does not require them to continuously hold the seat actuation button during the seat folding operation. Yet it is desirable to have an operator near a power folding seat as it folds to avoid problems that may be observed by a person as the seat is folded and unfolded. There is a need for a power seat folding system that does not require an operator to continuously hold a switch during an entire seat folding operation but will not operate unless the person is within close proximity to the vehicle during the folding operation. 
     Another problem associated with power seat folding mechanisms is that no feedback is typically provided to a user in the event the seat folding operation is unsuccessful. If, for example, the seat folding mechanism engages a foreign object and the motor stalls, the operator may not understand why the seat folding operation was interrupted. The operator also may not understand why the seat did not completely fold if the seat folding operation begins, but then terminates because the operator failed to continue to hold the button in during the entire folding operation. An operator may return the vehicle for service when no service is actually necessary if they do not understand why the seat folding operation was interrupted. There is a need for a power folding seat system that provides feedback to an operator in the event a seat folding operation is interrupted or to confirm that a seat has been moved to its fully folded or fully upright position for use as a seat. 
     These and other problems are addressed by Applicants&#39;invention as summarized below. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a system for controlling movement of a power-driven seat folding apparatus in a vehicle is disclosed. A motor that drives the seat folding apparatus is controlled by an electronic seat control module. The system comprises a plurality of weight sensors disposed on the seat base that provide a foreign object signal to the electronic seat control module when a foreign object of more than a predetermined weight is disposed on the seat base. The electronic seat control module provides an interrupt signal to the power-driven folding apparatus that stops operation of the power-driven folding apparatus after the foreign object signal is received from one or more of the weight sensors. 
     According to other aspects of the invention, the electronic seat control electronically monitors the plurality of weight sensors to sum an electrical characteristic of each of the weight sensors. The seat control monitors change in the sum prior to or during operation of the power-driven folding apparatus to detect the foreign object on the seat. During operation of the power-driven folding apparatus, if a lightweight object of less than the predetermined weight is disposed on the seat, but is pressed against the seat, added pressure is applied to the seat. If the added pressure meets or exceeds the pressure applied by the foreign object of more than the predetermined weight, a foreign object signal may be provided to the electronic seat control module. 
     According to other aspects of the present invention, a plurality of weight sensors may be secured to a substantially rigid support structure of the seat that supports a foam bun with the weight sensors being disposed below the foam bun. The weight sensors may be attached to a tray that is installed on top of the support structure. Alternatively, the support structure may have at least one opening and the plurality of weight sensors may be attached to a sensor tray that is installed beneath the support structure with the weight sensors aligned with the at least one opening or openings. 
     According to other aspects of the invention, the electronic control module may monitor the weight sensors until a desired position is obtained at the end of a seat folding operation. 
     A switch for initiating operation of the power-driven folding apparatus may establish a latched circuit for the folding apparatus that is released when the seat folding operation is completed. The latched circuit may also be released in the event the foreign object signal is received by the control module. A seat folding operation also may be prevented in the event an ignition key is placed in the vehicle ignition switch. 
     At least one manually actuated switch may be actuated to override the power-driven folding seat operation and allow manual folding of the seat. 
     According to another aspect of the invention, an operator perceptible output mechanism is provided that communicates status information regarding the status of the power-driven folding apparatus in the event operation of the power-driven folding apparatus is interrupted. The operator perceptible output mechanism may be a display panel on a key fob Rf transmitter or on the vehicle dashboard. The operator perceptible output mechanism may also be an audio output. 
     According to another aspect of the present invention, a system for controlling movement of a seat disposed in a vehicle that has a power-driven folding apparatus controlled by an electronic seat control module is provided. The system comprises a manually actuated switch that is actuated to initiate operation of the power-driven folding apparatus. The switch may be released after actuation during operation of the power-driven folding apparatus without effecting operation of the apparatus. A transponder is carried by a user of the vehicle. A transmitter/receiver communicates with the transponder and provides a proximity signal when the transponder is within a limited distance from the transmitter/receiver. The proximity signal is provided to the electronic seat control module. The electronic seat control module prevents operation of the power-driven folding apparatus when no proximity signal is provided to the electronic seat control module. 
     According to other aspects of the method of the invention, the transponder may be part of a passive entry Rf system that is operative to unlock the vehicle when the proximity signal is received. Operation of the power-driven folding apparatus is permitted to continue until completed unless the transponder is moved beyond the limited distance from the transmitter/receiver. 
     The transponder may have a plurality of manually-actuated switches that may be actuated to stop operation of the power-driven folding apparatus during operation of the apparatus. Alternatively, a manually actuated switch may be assembled to the vehicle and may be actuated to stop operation of the power-driven folding apparatus during operation of the folding apparatus. 
     An operator perceptible output mechanism may be used to communicate status information to the user regarding status of the power-driven folding apparatus in the event the electronic seat control module prevents operation of the power-driven folding apparatus. 
     These and other aspects of the present invention will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially fragmented top plan view of a vehicle having three rows of seats with the third row of seats being provided with an array of weight sensors; 
         FIG. 2  is a diagrammatic side elevation view of the rear seat of a vehicle having a child seat disposed in the rear seat and also showing the rear seat in several different positions; 
         FIG. 3  is an exploded perspective view of a row of vehicle seats provided with a pair of arrays of weight sensors; 
         FIG. 4  is an exploded perspective view of an alternative embodiment of a row of vehicle seats provided with a pair of arrays of weight sensors; and 
         FIG. 5  is a schematic representation of a seat control system made according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , a vehicle  10  such as a minivan, sport utility vehicle, or other vehicle having seats that may be folded into a cargo-carrying configuration is illustrated. The vehicle shown in  FIG. 10  has a first row of seats  12 , a second row of seats  14 , and a third row of seats  16 . The roof  18  and hatchback  20  of the vehicle  10  is partially cut-away in  FIG. 1  to reveal the third row of seats  16 . The third row of seats  16  is provided with a plurality of weight sensor arrays  24 . For example, the third row  16 , as illustrated, has three weight sensor arrays  24  that are disposed in the base  30  of the third row seat  16 . The back  32  of the third row seat  16  is shown in its generally upright or seating position. 
     Referring to  FIG. 2 , a third row of seats  16  is shown with a child seat  36  in the seat  16 . Child seats  36  are provided for transporting children and infants in a vehicle. Child seats  36  are generally left in a vehicle when not in use and may be forgotten if an operator is not careful when using a power-folding seat. With manual folding seats, the operator must unlock and release the seat parts to fold the seat and will ordinarily be able to observe foreign objects such as a child seat  36  as the seat is folded into a cargo-carrying position. With recently developed power-folding seats, the seat folding operation begins with a push of a button, but an operator may forget that a child seat or other foreign object is on the seat. If a power-folding seat engages a foreign object as it is moved, it may damage the seat, the seat folding mechanism, or the object. 
       FIG. 2  shows a third row seat  16  that includes a base  30  and a seat back  32  that are shown in solid lines in an upright position and is shown in dashed lines in a partially folded position, and phantom lines in a fully folded position. In the upright position, the child seat  36  is secured to the seat  16 . As the seat begins to fold, the seat back  32  rotates in a counterclockwise direction, as shown in  FIG. 2 , to a position that would cause interference with the child seat  36  unless the child seat  36  is removed. The seat folding operation continues with the seat back  32  rotated so that load floor segment  44  is in a horizontal and lowered position with the foam portion  42  of the seat back  32  disposed in the rear stowage well  40 . In this position, the load floor segment  44  forms part of the load floor  46  of the vehicle  10 . 
     Referring to  FIG. 3 , a rear row of seats  16  is shown to include a base  30  and a back  32 . The base  30  includes a foam bun that forms a supporting seat body that is covered by fabric, vinyl, or leather, as is well known in the art. Two weight sensor arrays  24 , made according to one embodiment of the invention, include a seat base support panel  50  and a plurality of weight sensors  52 . The weight sensors  52  are supported on two trays that hold the weight sensors  52  in openings  58  formed in the seat base support panel  50 . The weight sensors  52  are operatively connected to electronic seat controller  60 . The electronic seat controller  60  is interfaced with the seat control system, as will be more fully described with reference to  FIG. 5  below. 
     Referring to  FIG. 4 , an alternative embodiment of the rear seat  16  is shown to include a seat base  30  and seat back  32 , as previously described. The alternative embodiment of a seat base support panel  62  shown in  FIG. 4  supports weight sensors  64  that are retained on two trays  66 . The weight sensors  64  are interfaced with seat controller  68 . 
     In  FIGS. 3 and 4 , the weight sensors  52  and  64  are used to sense the presence of a foreign object on the seat  16 . If a foreign object of more than a predetermined weight is placed on the seat base  30 , the weight sensor will provide a signal to the seat controllers  60  and  68 . If during a seat movement procedure a lightweight object is on the seat and pressed against the seat, a signal may also be sent to the seat controllers  60  and  68 . 
     Referring to  FIG. 5 , a seat control system  70  is shown diagrammatically. Operation of the seat control system  70  begins by actuating a control switch  72 . Control switch  72  may be provided on the vehicle in one or more locations to allow operation of the seat folding system  70  by pressing a button on the dash or near a door. The control switch  72  may also be provided on a key fob, if desired. 
     A microcontroller  76  controls operation of the seat control system  70  to operate a seat control circuit  78 . Seat control circuit  78  controls one or more motors  80  that drive linkages supporting different parts of the seat  16 . Instead of an electric motor  80 , the motor could be a linear motor or cylinder, depending upon the design of the seat  16 . 
     A plurality of seat sensors  82  that may be arranged in an array of weight sensors  24  sense the presence of a foreign object on the seat  16 . The seat sensors  82  may be load cells or may be spring-biased elements that provide an output signal when an object of more than a predetermined weight is placed on the seat  16 . The seat sensors  82  may also be actuated by a lightweight object that is not more than the predetermined weight required to trigger the sensors. The lightweight object when contacted, or pinched, by the seat folding mechanism may provide an indication of a foreign object on the seat. For example, if the seat back  32  pivots to the position shown in dashed lines in  FIG. 2 , a lightweight object may be pressed into engagement with the seat base  30  sufficiently to cause the seat sensors  82  to provide an indication of a foreign object on the seat. 
     A passive Rf receiver  84  establishes a limited area around the vehicle  10  in which Rf communication with a transponder  90  may occur. The limited area is shown in  FIG. 1  as a cross-hatched area surrounding the vehicle and extending around the vehicle, for example, from 4 to 10 feet away from the vehicle. 
     The microcontroller  76  is connected to the vehicle bus by a seat-to-vehicle bus interface  86 . Bus circuitry  88  is provided in the seat control system to integrate the seat electronics with vehicle electronics. 
     The transponder  90  may be part of a key fob-type device. The transponder  90  includes a coil and an integrated chip that provides Rf communication with the passive Rf receiver of the vehicle. Whenever the transponder  90  is within the limited range of the Rf receiver, the transponder may be turned on and provide a Rf signal to the passive Rf receiver  84 . While the transponder  90  is within range, the seat control system  70  permits the microcontroller  76  to operate the seat control circuit and the motors  80  that drive the seat folding mechanism. 
     A feedback apparatus  92  is provided as part of the seat control circuit  78  to provide an operator perceptible output that can warn the operator that the seat folding operation was not completed. The feedback apparatus  92  may provide an indication that a foreign object is on the seat or another reason for the failure of the seat to complete its seat folding operation. For example, the feedback apparatus may provide information to advise the operator that the seat folding operation was interrupted because the transponder  90  was moved outside of the limited transmission zone of the passive Rf system. The feedback apparatus  92  may be provided on the vehicle dash as a text message or warning light. Alternatively, the feedback apparatus  92  may be part of the transponder  90  that can provide a message in the form of an icon or text message indicating the status of the seat control circuit  78 . The feedback apparatus  92  could also be an audio output such as a voice message that is transmitted over the vehicle audio system. In another alternative, the feedback apparatus  92  could be a telephone dialer that dials a telephone number of an operator&#39;s cell phone to provide an audio or visual message as to the status of the seat control circuit  78  or position of the seat  16 . 
     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.