초록 ▼

An improved pyrotechnic-operated seat belt tensioner provides variable energy management to enable tailoring operation of the seat belt tensioner to different applications. A seat belt tensioner has a reel mounting one end of a seat belt, a pressure chamber, and a piston having screw threads connect

An improved pyrotechnic-operated seat belt tensioner provides variable energy management to enable tailoring operation of the seat belt tensioner to different applications. A seat belt tensioner has a reel mounting one end of a seat belt, a pressure chamber, and a piston having screw threads connecting to the reel. The reel is rotatable to retract and extend the seat belt. The piston is mounted for movement in the chamber in response to activation of pyrotechnic devices, which exert a force on the piston, to rotate the reel to retract the seat belt. A pair of pyrotechnic devices are provided which are separately actuatable to selectively activated to vary the magnitude and duration of the force. A third pyrotechnic device is provided to selectively open a chamber vent. The piston and pressure chamber are configured to prevent piston rotation.

대표청구항 ▼

[ What is claimed is:] [1.] A seat belt tensioner having a reel for mounting one end of a seat belt and being rotatable to extend and retract the seat belt, a pressure chamber, and a piston having screw threads connecting to the reel, said piston being mounted for movement through the chamber in res

[ What is claimed is:] [1.] A seat belt tensioner having a reel for mounting one end of a seat belt and being rotatable to extend and retract the seat belt, a pressure chamber, and a piston having screw threads connecting to the reel, said piston being mounted for movement through the chamber in response to activation of a pyrotechnic device, which exerts a force on the piston, to rotate the reel to retract the seat belt, characterized by having a normally-closed vent for said chamber, a plurality of pyrotechnic devices which may be selectively activated to vary the magnitude and duration of said force, a first and second of said devices being selectively separately operable to produce different forces of different durations on said piston, and a third of said devices being selectively operable to open said vent to reduce the forces on said piston.