Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of Korean Application No. 10-2003-0045012, filed on Jul. 3, 2003, the disclosure of which is incorporated fully herein by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to a vehicle seat belt and, more particularly, to an automatic unbuckling seat belt system whereby a driver can conveniently use the seat belt under normal driving conditions and quickly unbuckle the belt in emergency situations. 
   BACKGROUND OF THE INVENTION 
   In general, a vehicle&#39;s seat belt is designed to protect the driver during a vehicle collision or the like to prevent injury. The seat belt, constructed with two or three supporting points, typically supports a driver&#39;s abdominal region and the chest. The buckling and unbuckling operation of the seat belt is normally manually performed. Therefore, there is a drawback in the conventional seat belt system in that the manual manipulation of the seat belt is inconvenient in emergency situations such as when escaping from the vehicle in the event of a vehicle collision or the like. 
   SUMMARY OF THE INVENTION 
   A preferred embodiment of the present invention provides an automatic unbuckling seat belt system employing an electromagnet. If the ignition key is taken out, the seat belt is automatically unbuckled, providing a convenience to the driver when he or she exits the vehicle. 
   In the preferred embodiment of the present invention, the automatic unbuckling seat belt system comprises a seat belt tongue formed with a groove. A seat belt buckle has a latch that it suspended in the groove to maintain a coupled state with the seat belt tongue, coupling to the seat belt tongue&#39;s groove. An ignition key detecting switch detects whether the ignition key is inserted into the ignition. An Electronic Control Unit (ECU) controls the removal of the seat belt buckle&#39;s latch from the seat belt tongue&#39;s groove if the ignition key detecting switch detects that the ignition key is taken out. A latch driving means removes the seat belt buckle&#39;s latch from the seat belt tongue&#39;s grove according to the control of the ECU. 
   The latch driving means includes a first relay that provides power when activated by the ECU. A first electromagnet generates the magnetic force by the power provided through the first relay and removes the latch by pulling it from the groove. 
   A spring is further equipped between the first electromagnet and the latch, and the spring pushes the latch to suspend it in the seat belt tongue&#39;s groove. 
   A seat belt releasing switch, mounted on the seat belt buckle, is equipped for releasing the coupled state of the seat belt, wherein once the seat belt releasing switch is manipulated, the ECU controls the latch driving means to remove the seat belt buckle&#39;s latch from the seat belt tongue&#39;s groove. 
   The automatic unbuckling seat belt system further comprises a first detecting switch equipped at the inlet of the seat belt buckle for detecting the initial insertion of the seat belt tongue into the seat belt buckle. A second detecting switch is equipped inside the seat belt buckle for detecting the complete insertion of the seat belt tongue into the seat belt buckle. A second electromagnet is equipped inside the seat belt buckle for pulling the seat belt tongue. A second relay provides power to the second electromagnet, wherein if the initial insertion of the seat belt tongue is detected by the first detecting switch, the ECU activates the second relay to pull the seat belt tongue, and if the complete insertion of the seat belt tongue is detected by the second detecting switch, then the ECU deactivates the second relay, thereby deactivating the second electromagnet. 
   The second detecting switch further comprises a contacting end being in contact to a front end of the seat belt tongue. A spring is installed at a rear side of the contacting end to provide resilience to the contacting end. 
   The seat belt buckle is equipped with a lamp, wherein if the seat belt is unfastened while the ignition key is inserted, then the ECU illuminates the lamp. 
   An opened and closed door detecting switch is further equipped to detect whether the vehicle door opens, wherein the ECU illuminates the lamp if the vehicle door opens, and turns off the lamp after a certain period of time if the door closes. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the nature and objects of the present invention, reference should be made to the following detailed description with the accompanying drawings, in which: 
       FIG. 1  is a constitutional view of an automatic unbuckling seat belt system for a vehicle according to an embodiment of the present invention; 
       FIG. 2  is a flowchart representing a buckling procedure of an automatic unbuckling seat belt system for a vehicle according to an embodiment of the present invention; 
       FIG. 3  is a flowchart representing an unbuckling procedure of an automatic unbuckling seat belt system for a vehicle by a manipulation of a seat belt releasing switch according to an embodiment of the present invention; and 
       FIG. 4  is a flowchart representing an unbuckling procedure of an automatic unbuckling seat belt system for a vehicle when the ignition key is taken out according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The preferred embodiment of the present invention will now be described in detail with reference to the attached drawings. 
   Referring to  FIG. 1 , the present invention comprises a seat belt tongue  10  formed with grooves  15  at both sides of the tongue. A buckle lamp  20  is installed at a seat belt buckle  6  and illuminates when a door opens. A first detecting switch  30  is equipped at the inlet portion of the seat belt buckle  6  and outputs a signal when it detects the initial insertion of the seat belt tongue  10 . A second detecting switch  40  is equipped at the farthest inner side of the seat belt buckle  6  and outputs a signal in the event of contact with the seat belt tongue  10 . An ignition key detecting switch  50  detects the insertion of the ignition key into the ignition and outputs a signal. An opened and closed door detecting switch  60  detects whether the vehicle door is opened or closed. A seat belt releasing switch  70  is manipulated for unbuckling the seat belt. An Electronic Control Unit (ECU)  80  receives signals outputted from the switches ( 30 ,  40 ,  50 ,  60 , and  70 ) and outputs a control signal according to a preset program. A first relay and second relay (RY 1  and RY 2 ) restrict the power provision according to the control signal outputted from the ECU  80 . A first electromagnet  90  generates a magnetic force via power applied through the first relay (RY 1 ) and pulls a latch  104  for releasing the coupled state of the seat belt tongue  10 . A second electromagnet  100  is mounted at the opposite side of the inlet of the seat belt buckle  6  and generates a magnetic force via power applied through the second relay (RY 2 ). 
   The second detecting switch  40  includes a contacting end  48  and a spring  46 , wherein the contacting end  48  contacts with one end of the seat belt tongue  10 , and the spring  46  is installed at a rear side of the contacting end  48  for applying resilience to the contacting end  48 . 
   The seat belt releasing switch  70  is preferably equipped at the seat belt buckle  6 . 
   The first electromagnet  90  is mounted at both sides of the seat belt buckle  6  and a spring  106  is equipped between the first electromagnet  90  and latch  104 . Accordingly, the latch  104  is designed to be suspended in the groove  15  of the seat belt tongue  10  by the resilience of the spring  106 . 
   With reference to  FIG. 2 , a buckling procedure of the seat belt according to an embodiment of the present invention comprises the steps of detecting whether the vehicle door is opened (ST 10 ); detecting whether the ignition key is inserted (ST 20 ); detecting whether the seat belt tongue  10  is initially inserted into the seat belt buckle  6  (ST 30 ); activating the second electromagnet  100  in the event of insertion of the seat belt tongue  10  (ST 40 ); outputting a signal when the seat belt tongue  10  is completely inserted (ST 50 ); and deactivating the second electromagnet  100  (ST 60 ). 
   With reference to  FIG. 3 , an unbuckling procedure of the seat belt by the manipulation of the seat belt releasing switch according to an embodiment of the present invention comprises the steps of detecting the manipulation of the seat belt releasing switch  70  (ST 100 ); activating the first electromagnet  90  when the seat belt releasing switch  70  is manipulated (ST 110 ); releasing the coupled state of the seat belt tongue  10  by activation of the first electromagnet  90  (ST 120 ); detecting whether the ignition key is inserted (ST 130 ); illuminating the buckle lamp  20  when the ignition key is inserted (ST 140 ); and turning off the light of the buckle lamp  20  if the ignition key is not inserted (ST 150 ). 
   As illustrated in  FIG. 4 , the unbuckling procedure of the seat belt when the ignition key is taken out according to an embodiment of the present invention comprises the steps of detecting whether the ignition key is taken out (ST 200 ); activating the first electromagnet  90  when the ignition key is withdrawn (ST 210 ); releasing the coupled state of the seat belt tongue  10  by activation of the first electromagnet  90  (ST 220 ); and turning off the light of the buckle lamp  20  (ST 230 ). 
   The operation and effect of the embodiment of the present invention will now be described in detail. 
   As shown in  FIG. 2 , when the driver opens the vehicle door to enter the vehicle (ST 10 ), the opened and closed door detecting switch  60  detects the opened door and the ECU  80  illuminates the buckle lamp  20  installed at the seat belt buckle  6  to notify the driver of the location of the seat belt buckle even in the dark. If the driver inserts the ignition key after sitting on the seat (ST 20 ) and introduces the seat belt tongue  10  into the seat belt buckle  6  (ST 30 ), the first detecting switch ( 30 ) equipped at the inlet of the seat belt buckle  6  detects the initial insertion of the seat belt tongue  10  and outputs a detecting signal to the ECU  80 . 
   The ECU  80  activates (ON) the second relay (RY 2 ) when the detecting signal is received and applies battery power (B+) to the second electromagnet  100  through the second relay (RY 2 ), thus allowing the second electromagnet  100  to generate magnetic force (ST 40 ). The seat belt tongue  10  is pulled by the magnetic force generated at the second electromagnet  100  so that the seat belt tongue  10  is completely inserted into the seat belt buckle  6  even with minimal force. The latch  104  suspends in the grooves  15  of both sides of the seat belt tongue  10  and the coupling of the seat belt is completed. When a front end of the seat belt tongue  10  contacts the contacting end  48  of the second detecting switch  40 , the second detecting switch  40  outputs a detecting signal to the ECU  80 , wherein the detecting signal represents the complete coupling of the seat belt (ST 50 ). The ECU  80  deactivates (OFF) the second relay (RY 2 ) when the detecting signal is received. The battery power to the second electromagnet  100  is this cut off and the second electromagnet does not generate magnetic force (ST 60 ). Once the seat belt is in a complete coupling state, the ECU  80  turns off the light of the buckle lamp  20 . 
   With reference to  FIG. 3 , in order to release the coupling state of the seat belt when the driver gets out of the vehicle, the driver manipulates the seat belt releasing switch  70  (ST 100 ). The ECU  80  detects the manipulation of the seat belt releasing switch  70  and activates (ON) the first relay (RY 1 ). When the first relay (RY 1 ) is activated (ON), the first electromagnet  90  is applied with battery power (B+) and generates magnetic force (ST 110 ). Once the first electromagnet  90  generates magnetic force, the latch  104  is pulled out of its suspended position in the groove  15  of the seat belt tongue  10 , enabling the seat belt tongue  10  to separate from the seat belt buckle  6 . The resilient force applied by the spring  46  of the second detecting switch  40  is transmitted to the seat belt tongue  10  through the contacting end  48  the seat belt tongue  10  is pushed out. Thus, the seat belt tongue  10  is decoupled from the seat belt buckle  6  and the coupling of the seat belt is released (ST 120 ). Then, the ignition key detecting switch  50  detects whether the ignition key is inserted (ST 130 ) and inputs the result to the ECU  80 . If the ignition key is inserted, the ECU  80  determines that the vehicle is in a temporarily parked state and turns on the light of the buckle lamp  20  to aid the driver to re-buckle the seat belt (ST 140 ). However, if the ignition key is withdrawn, the ECU  80  determines that the vehicle driving is finished and turns off the light of the buckle lamp  20  (ST 150 ). 
   On the other hand, as illustrated in  FIG. 4 , if the vehicle stops and the ignition key is withdrawn, the ignition key detecting switch  50  detects the above states and inputs a detecting signal to the ECU  80  (ST 200 ). Accordingly, the ECU  80  activates (ON) the first relay (RY 1 ) and applies battery power (B+) to the first electromagnet  90 , causing the first electromagnet  90  to generate magnetic force (ST 210 ). The magnetic force of the first electromagnet  90  pulls the latch  104 , pulling the latch from its suspended position in the groove  15  of the seat belt tongue  10 , resulting in a release of the coupled state of the seat belt tongue  10  (ST 220 ). The resilient force of the spring  46  of the second detecting switch  40  is transmitted to the seat belt tongue  10  through the contacting end  48 , and the seat belt tongue  10  is pushed out from the seat belt buckle  6 , thus releasing the coupling of the seat belt. As the coupling state of the seat belt is released, the ECU  80  deactivates the buckle lamp  20  (ST 230 ). The driver can now open the door and exit the vehicle as a result of the released coupling state of the seat belt. 
   The embodiment of the present invention may be modified by a person having ordinary knowledge of the technical field in this art as long as the embodiments are in the scope of the intrinsic characteristic of the present invention. Thus, the technical concept is not limited to the above embodiments. As apparent from the foregoing, there is an advantage in the present invention in that a lamp illuminates when the vehicle door is opened, allowing a driver to easily locate the seat belt. There is another advantage in that the coupling and release of the seat belt tongue and seat belt buckle is performed by the magnetic force of the electromagnet, resulting in a more convenient use of the seat belt. There is a further advantage in that the seat belt is automatically withdrawn if the ignition key is taken out, thus enabling the driver to conveniently exit the vehicle.

Technology Category: 4