Vehicle seat with integral, load limiting belt system

摘要

A vehicle seat (10) has a lower seat frame (14) and a seat back (16) pivoted about a recliner axis (20). An occupant (22) restraining shoulder belt (26) has an upper attachment point provided by a sliding belt guide (40) fixed to the top of a resilient, flexible elongated tower (36) attached to one side of the seat back (16). The tower (36) is normally unflexed, with the same orientation as the seat back (16), but is capable of bending with the belt guide (40) down and forwardly relative to the seat back and closer to the recliner axis (20) when a forward and downward force is applied to the belt guide (40). An inertially locking belt retractor (24) is rigidly fixed to the seat (10) below the belt guide (40). The retractor (24) provides a reserve length of belt (50) that extends up along the back of the tower (36) and over the belt guide (40) and then continues into the shoulder belt (26). In the event of rapid vehicle deceleration, the belt retractor (24) locks to the belt reserve length (50) as the occupant (22) moves relatively forward into the shoulder belt (26), thereby rapidly increasing tension in the shoulder belt (26) and applying a forward and downward bending force to the upper belt guide (40) and tower (36). In response, the tower (36) bends over and downwardly, allowing the belt reserve length (50) to move more horizontally along with the bending tower (36) as the upper guide (40) and shoulder belt (26) move forwardly with the occupant. This compound belt motion reduces the resulting tension load in the shoulder belt (26) considerably, as well as the moment applied to the seat back (16) about the recliner axis (20).