Seatbelt apparatus

Abstract

A seatbelt apparatus is provided which can constrain a passenger by ensuring removal of a slack of a lap belt when two pretensioners are activated under two different time frames. A pretensioner of a seatbelt retractor is activated first, and a shoulder belt and a lap belt are pulled in a direction toward the seatbelt retractor. Subsequently, a pretensioner of a belt anchor portion is activated and pulls a seatbelt toward the belt anchor portion, and hence a one-way tongue catches and locks the seatbelt. Accordingly, the shoulder belt is prevented from moving toward the lap belt through the tongue. Therefore, removal of the slack of the lap belt is ensured, and hence a lumber of the passenger is firmly fixed.

1 . A seatbelt apparatus comprising: 
 a seatbelt including a shoulder belt for constraining an upper half body of a passenger and a lap belt for constraining a lumber of the passenger;    a seatbelt retractor for withdrawably retracting the seatbelt and locking the seatbelt from being retracted in case of emergency;    a belt anchor portion for fixing a distal end of the seatbelt withdrawn from the seatbelt retractor to a vehicle body;    a tongue slidably supported by the seatbelt and partitioning between the shoulder belt and the lap belt;    a buckle fixed to the vehicle body and capable of being engaged by the tongue;    a first and a second pretensioner, wherein each may be provided in at least two devices selected from the seatbelt retractor, the belt anchor portion and the buckle, wherein the first and second pretensioners are activated to pull the seatbelt in case of emergency, and the first and second pretensioners are adapted to be activated under two time frames in such a manner that the second pretensioner is activated after having activated the first pretensioner; and    a belt one-way movement preventing mechanism for preventing the shoulder belt from moving toward the lap belt when the second pretensioner is activated.    
   
   
       2 . A seatbelt apparatus according to  claim 1 , wherein the tongue is a one-way tongue which prevents the shoulder belt from moving toward the lap belt when a predetermined pulling force toward the shoulder belt is applied to the seatbelt and, in this state, a force larger than the predetermined pulling force is applied to the seatbelt in the direction toward the lap belt.  
   
   
       3 . A seatbelt apparatus according to  claim 1 , wherein the tongue further comprises: 
 a plate covered by a mold; and    a webbing guide for preventing the webbing from moving in a direction when a predetermined force is applied to the seatbelt, the webbing guide including a lock bar configured so that the webbing is secured between the lock bar and the mold when the force is applied.    
   
   
       4 . A seatbelt apparatus according to  claim 3 , wherein the plate is formed of a substantially T-shaped metallic plate having a laterally extending portion and a vertically extending portion extending vertically from a center of the laterally extending portion, 
 wherein the laterally extending portion is formed with a first square opening extending in the lateral direction and the vertically extending portion is formed with a second square opening extending in the vertical direction adapted so that a latch member of the buckle engages the second square opening; and    a first and second side wall extend at a first and second end of the laterally extending portion, wherein the first and second side walls are each formed with at least one hole of the same size and at least one recessed groove of the same size.    
   
   
       5 . A seatbelt apparatus according to  claim 3 , wherein the webbing guide further comprises a guide body, having a plurality of guide body surfaces wherein a plurality of square shaped recesses is formed on one of the plurality of guide body surfaces.  
   
   
       6 . A seatbelt apparatus according to  claim 3 , wherein the tongue further comprises: 
 a revolving shaft set across a tongue body;    a through hole for rotatably supporting the webbing guide;    a lock bar supported by the webbing guide so as to be capable of relative rotation;    a pair of guide shafts for rotatably supporting the lock bar; and    a bar spring mounted to the mold and the lock bar for urging the lock bar constantly in one direction.    
   
   
       7 . A seatbelt apparatus according to  claim 3 , wherein a first gap is defined between a portion of the webbing guide and a portion of the mold and a second gap is defined between a corner of a lock body of the lock bar and a portion of the mold, wherein the first gap and second gap are larger than the thickness of a seatbelt wherein when the seatbelt passes through the first gap and is guided by the webbing guide and then passes through the second gap, the seatbelt tongue slides smoothly with respect to the seatbelt.  
   
   
       8 . A seatbelt tongue according to  claim 6 , wherein when a force larger than a predetermined magnitude is applied to the webbing guide, the webbing guide rotates counterclockwise against a moment generated by a urging force of the bar spring, the pair of guide shafts move linearly along a plurality of guide grooves of the mold while the lock bar rotates clockwise about the pair of guide shafts, wherein the seatbelt is caught between a corner of the lock body and the portion of the mold and is locked.  
   
   
       9 . A seat belt tongue configured to be slidably supported by a seatbelt webbing and configured to engage with a buckle, comprising: 
 a plate covered by a mold; and    a webbing guide for preventing the seatbelt webbing from moving in a direction when a predetermined force is applied to the seatbelt, the webbing guide including a lock bar configured so that the webbing is secured between the lock bar and the mold when the force is applied.    
   
   
       10 . A seatbelt tongue according to  claim 9 , wherein the plate is formed of a substantially T-shaped metallic plate having a laterally extending portion and a vertically extending portion extending vertically from a center of the laterally extending portion, 
 wherein the laterally extending portion is formed with a first square opening extending in the lateral direction and the vertically extending portion is formed with a second square opening extending in the vertical direction adapted so that a latch member of the buckle engages the second square opening; and    a first and second side wall extend at a first and second end of the laterally extending portion, wherein the first and second side walls are each formed with at least one hole of the same size and at least one recessed groove of the same size.    
   
   
       11 . A seatbelt tongue according to  claim 10 , wherein the webbing guide further comprises a guide body, having a plurality of guide body surfaces wherein a plurality of square shaped recesses is formed on one of the plurality of guide body surfaces.  
   
   
       12 . A seatbelt tongue according to  claim 10 , wherein the tongue further comprises: 
 a revolving shaft set across a tongue body;    a through hole for rotatably supporting the webbing guide;    a lock bar supported by the webbing guide so as to be capable of relative rotation;    a pair of guide shafts for rotatably supporting the lock bar; and    a bar spring mounted to the mold and the lock bar for urging the lock bar constantly in one direction.    
   
   
       13 . A seatbelt tongue according to  claim 12 , wherein a first gap is defined between a portion of the webbing guide and a portion of the mold and a second gap is defined between a corner of a lock body of the lock bar and a portion of the mold, wherein the first gap and second gap are larger than the thickness of a seatbelt wherein when the seatbelt passes through the first gap and is guided by the webbing guide and then passes through the second gap, the seatbelt tongue slides smoothly with respect to the seatbelt.  
   
   
       14 . A seatbelt tongue according to  claim 13 , wherein when a force larger than a predetermined magnitude is applied to the webbing guide, the webbing guide rotates counterclockwise against a moment generated by a urging force of the bar spring, the pair of guide shafts move linearly along a plurality of guide grooves of the mold while the lock bar rotates clockwise about the pair of guide shafts, wherein a seatbelt is caught between a corner of the lock body and the portion of the mold and is locked.