초록 ▼

To provide a pre-tensioner which can effectively use ignition pressure of a gas generator and can be constructed in a compact form as a whole and have lighter weight, a pre-tensioner 10 is mounted outside of a side wall 50 of the frame 2 by a base 41. A hexagonal head portion 4d of a reel 4 penetrat

To provide a pre-tensioner which can effectively use ignition pressure of a gas generator and can be constructed in a compact form as a whole and have lighter weight, a pre-tensioner 10 is mounted outside of a side wall 50 of the frame 2 by a base 41. A hexagonal head portion 4d of a reel 4 penetrates a base 41. Fixed to the outer periphery of the hexagonal head portion 4d is a pinion 23. The pinion 23 is provided with external teeth 24 uniformly formed around the periphery thereof. A ring gear 30 is disposed to surround the pinion 23. The ring gear 30 has internal teeth 31 engageable with the external teeth 24 of the pinion 23. The ring gear 30 has levers 32, 33 projecting outwardly, which are formed on the outer periphery of the ring gear 30 at predetermined interval. The lever 32 of the ring gear 30 is substantially in contact with the head ball 20-15 within the pipe 21.

대표청구항 ▼

1. A pre-tensioner which rotates a take-up shaft of a seat belt retractor in the belt take-up direction to impart pre-tension on a belt in case of emergency, the pre-tensioner comprising:a gas generator; a plurality of driving members which are accelerated by gas from the gas generator; a passage fo

1. A pre-tensioner which rotates a take-up shaft of a seat belt retractor in the belt take-up direction to impart pre-tension on a belt in case of emergency, the pre-tensioner comprising:a gas generator; a plurality of driving members which are accelerated by gas from the gas generator; a passage for guiding the driving members; a ring gear having a plurality of levers on the outer periphery thereof which are pressed by some of the driving members to receive a driving force; a pinion having external teeth and being fixed to the take-up shaft, the ring gear having internal teeth engageable with the external teeth; and a clutch mechanism disposed between the ring gear and the pinion, wherein the clutch mechanism engages the internal teeth of the ring gear with the external teeth of the pinion such that the accelerated driving members press the levers of the ring gear to move the ring gear; the clutch mechanism is not coupled before the pre-tensioner is actuated, as the ring gear rotates when the pre-tensioner is operative, the clutch mechanism is coupled, and wherein a head one of the driving members is substantially in contact with one of the driving points of the ring gear.