Belt retractor with force-limiting arrangement

Abstract

A belt retractor has a belt spool ( 12 ) rotatably mounted in a frame ( 10 ), a disc adapted to be blocked against rotation on the frame ( 10 ), and a force-limiting arrangement. The force-limiting arrangement includes a cutting body ( 22 ) which is adapted to be guided into a coupling position in which the cutting body ( 22 ) couples the belt spool ( 12 ) to the disc ( 16 ) such that upon a relative rotation between the disc ( 16 ) and the belt spool ( 12 ), the cutting body ( 22 ) cuts material. The force-limiting arrangement has a guiding-in mechanism which guides the cutting body ( 22 ) into the coupling position as a function of accident-related data.

1 . A belt retractor, comprising a belt spool rotatably mounted in a frame, a disc adapted to be blocked against rotation on the frame, and a force-limiting arrangement with a cutting body which is adapted to be guided into a coupling position in which the cutting body couples the belt spool to the disc such that upon a relative rotation between the disc and the belt spool, the cutting body cuts material, the force-limiting arrangement having a guiding-in mechanism which guides the cutting body into the coupling position as a function of accident-related data.  
   
   
       2 . The belt retractor according to  claim 1 , wherein the guiding-in mechanism has at least one oblique plane formed on the belt spool or on the disc, the cutting body being adapted to slide on the disc into the coupling position.  
   
   
       3 . The belt retractor according to  claim 1 , wherein the cutting body is an inertial body which on exceeding a particular angular acceleration or rotational speed and subsequent blocking of the belt spool is moved into the coupling position owing to one of the inertia of the inertial body, and the centrifugal force F Z  acting on the inertial body.  
   
   
       4 . The belt retractor according to  claim 1 , wherein the cutting body is coupled to a control element in the form of an inertial body which on exceeding a particular angular acceleration or rotational speed and subsequent blocking of the belt spool is moved into the coupling position owing to one of: the inertia of the inertial body, and the centrifugal force F Z  acting on the inertial body.  
   
   
       5 . The belt retractor according to  claim 1 , further including a locking mechanism which holds the cutting body in an initial position.  
   
   
       6 . The belt retractor according to  claim 5 , wherein the locking mechanism has a pre-stressing spring.  
   
   
       7 . The belt retractor according to  claim 5 , wherein the locking mechanism has a mechanical stop.  
   
   
       8 . The belt retractor according to  claim 1 , wherein the guiding-in mechanism is coupled to a switching mechanism of the belt retractor with which, on rotation of the belt spool, switching functions can be carried out.  
   
   
       9 . The belt retractor according to  claim 8 , wherein the guiding-in mechanism has a guiding-in element, connected with the cutting body, which is movable by the switching mechanism.