| 摘要 |
PURPOSE:To provide a fastener for a seat belt, which comprises driving means, the driving means being capable of, in an emergency, expanding a winding shaft radially to wind up the seat belt thereby fastening the seat belt, and the fastener being made compact. CONSTITUTION:In a case of emergency such as a collision of cars, when a pendulum 81 is swung by a predetermined distance, a pawl 82a locks a gear 3a to prevent a winding shaft 4 from its rotation. In this state, current is passed through by a signal from a collision sensor to explode a gunpowder 72, a high pressure of gas generated in a large amount thereby causes pistons 6a, 6b in a gunpowder chamber 71 to abut bases of gears 3a, 3b, while the pistons being guided by a center shaft 2, section members 4a, 4b, 4c, 4d which constitute the winding shaft 4 are pushed and expanded outwardly by slanted surfaces 61a, 61b of the pistons which engage inner slanted surfaces 51, 52 of the section members, and therefore the outer diameter of the shaft 4 to which one end of a seat belt S is connected is increased to wind up the belt S. |
