| 摘要 |
A safety belt retractor incorporates a reel (14) upon which part of the safety belt is wound, the reel being mounted in a frame. The reel carries locking elements (25) which are moveable from an initial retracted position to an extended position in response to high acceleration of the reel (14). An inertia element (47) is mounted to the reel, and is provided with peripheral teeth (48) which engage cooperating teeth (57) on a coupling element (51). The coupling element (51) is rotatably mounted relative to the reel and carries an engagement element (59) to engage the locking element. When the coupling element (51) rotates rotationally relative to the reel, the locking elements are moved to the locking position. An inertia mass spring (60) is provided engaging the reel (14) and the inertia element (47). The tension in the spring depends upon the amount of safety belt that is wound onto the reel. When a lot of safety belt is wound on the reel the inertia mass spring provides a firm coupling with the inertia element (47) meaning that a very high acceleration has to be given to the reel to effect unlocking. When almost all of the safety belt has been paid out the inertia mass spring (60) is effectively disconnected from the inertia mass and provides no effect enabling locking to be accomplished at a low acceleration of the reel. |
