Patent Publication Number: US-2003226703-A1

Title: Seatbelt safety device for vehicles

Description:
FIELD OF THE INVENTION  
       [0001] This invention relates to a seatbelt safety device for vehicles including passenger cars, and more particularly to a seatbelt safety device for preventing vehicles from starting an engine without passengers wearing seatbelts.  
       BACKGROUND OF THE INVENTION  
       [0002] Wearing seatbelts is crucial for safety of drivers and passengers in vehicles including passenger cars. In the past, vehicles were allowed to move without occupants wearing seatbelts. Therefore, when an accident happened, people might have lost their lives.  
       [0003] A safety device is needed for preventing the vehicles from starting an engine without confirming wearing of seatbelts by occupants. The applicant of this application has suggested such a seatbelt safety device, as disclosed in his laid-open publications Nos. 1999-321,560 titled “SEATBELTS WITH BUILT-IN SWITCH” (published Nov. 24, 1999) and 2001-287,623 titled “DEVICE FOR PREVENTING MOVING WITHOUT WEARING OF SEATBELTS” (published Oct. 16, 2001). His underlying concept is that a simplest circuit or an arrangement with a minimum of components leads to a best safety or safest device, because the simplest circuit experiences a smallest chance of malfunction or erroneous operation.  
       [0004] Japanese laid-open publication 1995-251,711 (published Oct. 3, 1995) shows and discloses a much complicated seatbelt safety circuit arrangement for preventing a vehicle from start moving when a driver or passenger is seated but a seat belt remains unfastened and the speed of the vehicle remains still zero.  
       SUMMARY AND OBJECTS OF THE INVENTION  
       [0005] Accordingly, it is an object of the present invention to provide a seatbelt safety device for preventing vehicles from starting an engine without drivers or passengers wearing seatbelts.  
       [0006] It is another object of the present invention to provide a seatbelt safety device which includes a minimum of components for minimizing risk of malfunction or erroneous operation.  
       [0007] It is still another object of the present invention to provide a seatbelt safety device which allows a vehicle to continue moving, even if a seatbelt is unfastened in the middle of driving, once the vehicle has started to move with confirmation of wearing of a seatbelt by an occupant.  
       [0008] According to the present invention, there is provided an improved seatbelt safety device for preventing vehicles from starting an engine by an engine key without drivers or passengers wearing seatbelts. The seatbelt safety device for a vehicle comprises an engine for the vehicle, an engine starter key for starting the engine, a seatbelt with a built-in ON/OFF switch, an occupant&#39;s seating detecting ON/OFF switch or sensor, an electric circuit for connecting the seatbelt ON/OFF switch and the occupant&#39;s seating detecting ON/OFF switch or sensor between the engine and the engine starter key for enabling the engine starter key to start the engine only when an occupant is seated and the seatbelt is fastened.  
       [0009] In a preferred embodiment of the present invention, the seatbelt switch is connected in parallel with the occupant&#39;s seating detecting switch or sensor. A pair of the seatbelt switch and the occupant&#39;s seating switch or sensor is provided for the safety of one driver or passenger.  
       [0010] If necessary or desirable, more than one pair of the seatbelt switch and the occupant&#39;s seating detecting switch or sensor is provided for up to the total number of occupants or passengers in the vehicle. All of the seatbelt switches are connected in series, while all of the occupant&#39;s seating detecting switches or sensors are also connected in series.  
       [0011] The seatbelt safety device of the present invention further comprises a short circuit between the engine starter key and the engine for allowing the vehicle to continue moving, even if the seatbelt is unfastened in the middle of driving, once the vehicle has started to move with confirmation of wearing of a seatbelt by an occupant. A warning alert may provided by a sound IC to notify the occupants of unfastened seatbelt when the seatbelt is unfastened in the middle of driving. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0012]FIG. 1 is a front view of a seatbelt having a built-in switch for use with a preferred embodiment of the present invention; and  
     [0013]FIG. 2 is a circuit diagram of an electric circuit for a seatbelt safety device according to the preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0014] Referring to FIG. 1, there is illustrated a seatbelt having a built-in ON/OFF switch or sensor for use with a preferred embodiment of the present invention. A seatbelt  11  has a belt latch plate  12  which may be fully inserted into a buckle  13 . A seat buckle detector (switch or sensor)  14  typically comprises a pressure-sensing bladder or a load-responsive electric ON/OFF switch installed in the interior of the buckle  13 . The seat buckle detector  14  indicates an engaged or non-engaged state of the buckle  13  and provides ON and OFF electric signals depending on the seat buckle status. When the belt latch plate  12  is fully inserted into the buckle  13 , the detector  14  turns ON and activates an electric circuit as discussed below for a seatbelt safety device according to the preferred embodiment of the present invention. The belt buckle detector  14  remains OFF unless activated with occupant&#39;s wearing of the seatbelt. If necessary and desirable, more than one belt buckle detector  14  may be provided and a plurality of the belt buckle detectors  14  may be provided for up to a total number of seatbelts installed in a passenger vehicle. The detector  14  as shown in FIG. 1 are not meant to the limit the invention to any particular type of switch or sensor.  
     [0015] A seat occupancy detector (switch or sensor)  15  is provided to detect whether an occupant is sitting in the seat of the vehicle. Although not shown in the drawings, the seat occupancy detector  15  may be installed inside the seat mat or outside but in the neighborhood of the seat mat to an extent which the switch or sensor may find whether the occupant is sitting in the seat. The seat occupancy detector may be of any conventional type including an electric ON/OFF micro switch or infrared non-contact approach sensor. More than one seat occupancy detector  15  may be provided for more than one occupant. Like the belt buckle switch or sensor  14 , the number of the seat occupancy detectors  15  equal to the number of the seats in the vehicle may be provided. When the occupant has sit in the seat in the vehicle, the seat occupancy detectors  15  is activated to disconnect the electric circuit for the seatbelt safety device. Under this condition, an engine of the vehicle will not start even if a starter key is turned ON. It will be noted that the seat occupancy detector  15  is normally ON. However, if the occupant wears the seatbelt  11  to turn ON the seat buckle detector  14  and activate the electric circuit for the seatbelt safety device, the engine is allowed to start.  
     [0016]FIG. 2 illustrates the electric circuit for the seatbelt safety device according to the preferred embodiment of the present invention. The illustrated electric circuit for the seatbelt safety device is disposed between an electric battery  16  and the engine  17  for controlling electric supply from the battery  16  to the engine  17 , depending upon the status of the belt buckle detectors  14  and the seat occupancy detectors  15 . A starter key switch  18  is interposed between the battery  16  and the engine  17 . The belt buckle detector  14  and the seat occupancy detector  15  are connected in parallel between the battery  16  and the engine  17 . If the plurality of the belt buckle detectors  14  and the seat occupancy detectors  15  are connected in the electric circuit, then all the belt buckle detectors  14  are connected in series between the battery  16  and the engine  17  and all the seat occupancy detectors  15  are also connected in series. Therefore, when all the occupants are sitting in the individual seats in the vehicle and wearing the seatbelts, the power supply from the battery  16  is provided via the belt buckle detectors  14  to power the engine  17 .  
     [0017] If no one is sitting in the vehicle (that is, the seat occupancy detector  15  remains ON) but someone turns on the starter key  18 , then the engine  17  is allowed to start. This feature may be useful when the engine  17  has to be warmed under severe cold weather or other condition. However, once an occupant has gotten into the vehicle and sat in the seat in the vehicle to turn OFF the seat occupancy detector  15 , the seatbelt safety device according to the present invention becomes operative so that the engine  17  will not start unless the occupant wear the seatbelt.  
     [0018] The driver or occupant may unfasten the seatbelt at toll gates or other places or may shift in the seat during the driving so that the electric circuit would respond to any changes in the seat buckle switch or sensor  14  or the seat occupancy detector  15 . According to the preferred embodiment of the present invention, this potential risk of malfunction or erroneous operation will be avoided by providing a short circuit  19  including a short-circuit relay. Once the engine  17  has started, a coil  20  of the short circuit relay  19  is energized to keep the short circuit relay ON so that the engine  17  keeps moving even though the seat buckle detector  14  or seat occupancy detector  15  changes in status during driving. A voice IC  21  is also provided to sound an alert when the occupant is sitting in the seat but without wearing the seatbelt  11 .  
     [0019] As discussed above, when the occupant sits in a seat, the seat occupancy detector  15  to detect whether a passenger is sitting in the seat is activated, cutting off the electrical circuit, therefore not allowing the engine  17  to start when starter switch  18  is activated and the vehicle would not move. But when the seatbelt  11  is worn, the seat buckle detector  14  is activated and connects the electrical circuit, the engine  17  is allowed to start and the vehicle may move. If the seatbelt  11  is unfastened while the vehicle is in motion, the short circuit relay  19  would not stop the engine  17  but the voice IC  21  would provide a sound warning to fasten the seatbelt, therefore saving human lives in a reliable and faultless manner.  
     [0020] Various other modifications and variations will no doubt occur to those skilled in the arts to which this invention pertains. Such variations and modifications, which generally rely on the teachings through which this disclosure has advanced the art, are properly considered within the scope of this invention. This disclosure should thus be considered illustrative, not limiting; the scope of the invention is instead defined by the following claims.