Seat belt web stop apparatus and method

Abstract

A web stop button may utilize plastic deflection to provide more secure and reliable attachment to a seat belt. The web stop button may have a first button member and a second button member. The first and second button members may each have multiple pieces attached together via crimping or the like. Protrusions extend from the first button member and plastically deflect within the second member in response to force urging the first and second members together. The protrusions may be capable of piercing the seat belt strap and/or a portion of the second button member. Plastic caps may be used on one or both of the button members to provide a larger web stop button and enhanced trim color matching capability. The second button member is shaped to induce the plastic deflection, and may therefore have a simple domed shape or a more complex, generally toroidal domed shape.

1 . A seat belt for restraining motion of a vehicle occupant, the seat belt comprising: 
 a strap having a first side and a second side;    a first button member disposed adjacent to the first side, the first button member comprising a first protrusion extending through the strap; and    a second button member disposed adjacent to the second side, the second button member comprising an enclosure shaped to induce plastic deflection of the first protrusion in response to pressure urging the first and second button members together, wherein the plastically deflected first protrusion is shaped to interlock with the enclosure to hold the first and second button members together.    
     
     
         2 . The seat belt assembly of  claim 1 , wherein the first protrusion comprises a first sharp prong and the enclosure comprises a domed chamber.  
     
     
         3 . The seat belt assembly of  claim 2 , wherein the first button member further comprises a second sharp prong symmetrically arranged with the first sharp prong about an axis of symmetry of the first button.  
     
     
         4 . The seat belt assembly of  claim 3 , wherein the first and second sharp prongs are plastically deflected in such a manner that the first and second sharp prongs are folded toward each other to lie generally perpendicular to the axis of symmetry.  
     
     
         5 . The seat belt assembly of  claim 1 , wherein the first button member comprises a protrusion piece in which the first protrusion is integrally formed, and a backing piece that retains the protrusion piece, and wherein the second button member comprises a capture piece and a dome piece that retains the capture piece to define the enclosure.  
     
     
         6 . The seat belt assembly of  claim 1 , wherein the first and second button members are constructed substantially of metal.  
     
     
         7 . The seat belt assembly of  claim 6 , further comprising a plastic cap attached to one of the first and second button members.  
     
     
         8 . A seat belt for restraining motion of a vehicle occupant, the seat belt comprising: 
 a strap having a first side and a second side;    a latch plate shaped to slidably capture the strap; and    a web stop button attached to the strap to restrict motion of the latch plate along the strap, the web stop button comprising a first button member disposed adjacent to the first side and a second button member disposed adjacent to the second side, wherein the first button member is shaped such that a portion of the first button member deflects plastically to interlock with the second button member in response to pressure urging the first and second button members together.    
     
     
         9 . The seat belt of  claim 8 , wherein the first button member comprises a first protrusion and the second button member comprises an enclosure, wherein the first protrusion plastically deflects to interlock with the enclosure in response to pressure urging the first and second button members together.  
     
     
         10 . The seat belt of  claim 9 , wherein the first protrusion comprises a sharp prong and the enclosure comprises a domed chamber having a domed interior surface shaped to contact and deflect the first protrusion in response to pressure urging the first and second button members together.  
     
     
         11 . The seat belt of  claim 10 , wherein the domed chamber is disposed to be pierced by the sharp prong in response to pressure urging the first and second button members together.  
     
     
         12 . The seat belt of  claim 10 , wherein the first button member further comprises a second sharp prong symmetrically arranged with the first sharp prong about an axis of symmetry of the first button.  
     
     
         13 . The seat belt of  claim 12 , wherein the first and second sharp prongs plastically deflect by folding generally toward each other to lie nearly perpendicular to the axis of symmetry.  
     
     
         14 . The seat belt of  claim 9 , wherein the first button member comprises a protrusion piece in which the first protrusion is integrally formed, and a backing piece that retains the protrusion piece, and wherein the second button member comprises a capture piece and a dome piece that retains the capture piece to define the enclosure.  
     
     
         15 . The seat belt of  claim 8 , wherein the first and second button members are constructed substantially of metal.  
     
     
         16 . The seat belt of  claim 15 , wherein the first and second button members are constructed substantially of brass.  
     
     
         17 . The seat belt assembly of  claim 15 , further comprising a plastic cap attached to one of the first and second button members.  
     
     
         18 . The seat belt assembly of  claim 17 , wherein the plastic cap comprises a first button cap attached to the first button member, the seat belt assembly further comprising a second button cap made of plastic and attached to the second button member.  
     
     
         19 . The seat belt assembly of  claim 8 , wherein the strap comprises a first end, a second end, and an intermediate portion between the first and second ends, wherein the intermediate portion is slidably captured by the latch plate, the seat belt assembly further comprising a retractor attachable to the first end and the vehicle to take up the first end, an anchor attachable to the second end and the vehicle to anchor the second end to the vehicle, and a buckle attachable to the vehicle to removably retain the latch plate.  
     
     
         20 . A seat belt for restraining motion of a vehicle occupant, the seat belt comprising: 
 a strap having a first side and a second side;    a first button member disposed adjacent to the first side, the first button member comprising a first protrusion extending through the strap; and    a second button member disposed adjacent to the second side, the second button member comprising an enclosure pierced by the first protrusion in response to pressure urging the first and second button members together such that the first protrusion and the enclosure are interlocked to hold the first and second button members together.    
     
     
         21 . The seat belt of  claim 20 , wherein the first protrusion comprises a sharp prong and the enclosure comprises a domed chamber having a domed interior surface shaped to contact and deflect the first protrusion in response to pressure urging the first and second button members together.  
     
     
         22 . The seat belt of  claim 21 , wherein the first button member further comprises a second sharp prong symmetrically arranged with the first sharp prong about an axis of symmetry of the first button.  
     
     
         23 . The seat belt of  claim 22 , wherein the first and second sharp prongs plastically deflect by folding generally toward each other to lie nearly perpendicular to the axis of symmetry.  
     
     
         24 . The seat belt of  claim 20 , wherein the first button member comprises a protrusion piece in which the first protrusion is integrally formed, and a backing piece that retains the protrusion piece, and wherein the second button member comprises a capture piece and a dome piece that retains the capture piece to define the enclosure.  
     
     
         25 . The seat belt of  claim 20 , wherein the first and second button members are constructed substantially of metal.  
     
     
         26 . The seat belt assembly of  claim 25 , further comprising a plastic cap attached to one of the first and second button members.  
     
     
         27 . A method for manufacturing a seat belt for restraining motion of a vehicle occupant, the seat belt comprising a strap having a first side and a second side, a first button member comprising a first protrusion, and a second button member comprising an enclosure, the method comprising: 
 forming an opening in the strap;    disposing the first button member adjacent to the first side such that the first protrusion extends through the opening;    disposing the second button member adjacent to the second side; and    pressing the first and second button members together such that the first protrusion enters the enclosure and is plastically deflected to interlock with the enclosure to hold the first and second button members together.    
     
     
         28 . The method of  claim 27 , wherein forming the opening in the strap comprises piercing the strap pressing the first protrusion into the first side of the strap.  
     
     
         29 . The method of  claim 27 , wherein the first protrusion comprises a sharp prong and the enclosure comprises a domed chamber having a domed interior surface, wherein plastically deflecting the first protrusion comprises urging a tip of the sharp prong against the domed interior surface.  
     
     
         30 . The method of  claim 29 , wherein the first button member further comprises a second sharp prong symmetrically arranged with the first sharp prong about an axis of symmetry of the first button, wherein the first and second button members are pressed together such that the second sharp prong enters the enclosure and is plastically deflected to interlock with the enclosure, wherein the first and second sharp prongs are plastically deflected to lie generally alongside each other.  
     
     
         31 . The method of  claim 29 , wherein pressing the first and second button members together such that the first protrusion enters the enclosure comprises piercing the enclosure with the first protrusion.  
     
     
         32 . The method of  claim 27 , wherein the first and second button members are constructed substantially of metal, wherein the seat belt further comprises a plastic cap, the method further comprising attaching the plastic cap to one of the first and second button members.  
     
     
         33 . A method for manufacturing a seat belt for restraining motion of a vehicle occupant, the seat belt comprising a strap having a first side and a second side, a first button member comprising a first sharp prong and a second sharp prong, and a second button member, the method comprising: 
 aligning an axis of the first button member with an axis of the second button member;    pressing the first and second sharp prong into the first side to form first and second openings by piercing the strap, wherein the sharp prongs are formed substantially of a metal; and    pressing the first and second button members together to induce the first and second button members to interlock with each other, thereby holding the first and second button members together.    
     
     
         34 . The method of  claim 33 , wherein the second button member comprises a domed chamber having a domed interior surface, wherein inducing the first and second button members to interlock with each other comprises urging tips of the first and second sharp prongs against the domed interior surface to plastically deflect the first and second sharp prongs, thereby causing the first and second sharp prongs to interlock with the domed chamber.  
     
     
         35 . The method of  claim 34 , wherein the first button member comprises a backing member constructed substantially of metal and the second button member comprises a dome member constructed substantially of metal, the method further comprising attaching a plastic cap to one of the backing member and the dome member.