초록 ▼

A device for tightening a vehicle seatbelt has a piston-like drive member arranged in a guide tube. A propellant gas drives the drive member by expanding in a pressure chamber adjoining the drive member. A movement transmitting system connects the drive member and the seatbelt to be tightened. The d

A device for tightening a vehicle seatbelt has a piston-like drive member arranged in a guide tube. A propellant gas drives the drive member by expanding in a pressure chamber adjoining the drive member. A movement transmitting system connects the drive member and the seatbelt to be tightened. The drive member is a step piston which is provided with a first pressure chamber and a second pressure chamber. A propellant gas discharge system supplies the propellant gas to the pressure chambers. The propellant gas flows into the first pressure chamber and the step piston is set into motion by the propellant gas. The propellant gas acting in the first pressure chamber clears a discharge orifice in the second pressure chamber after covering a first distance so the propellant gas flowing into the second pressure chamber and acting therein additionally drives the step piston.

대표청구항 ▼

[ What is claimed is:] [1.] A device for tightening a seatbelt comprising:a piston-like drive member arranged in a guide tube,a drive means for producing a propellant gas which drives the drive member by expanding in a pressure chamber adjoining the drive member, and a movement transmitting system c

[ What is claimed is:] [1.] A device for tightening a seatbelt comprising:a piston-like drive member arranged in a guide tube,a drive means for producing a propellant gas which drives the drive member by expanding in a pressure chamber adjoining the drive member, and a movement transmitting system connecting the drive member and the seatbelt to be tightened,the drive member is a step piston which is provided with a first pressure chamber and a second pressure chamber, in that a propellant gas discharge system for supplying the propellant gas into the pressure chambers in the starting position of the step piston adjoins the latter in such a way that the first and second pressure chambers are separated from one another with a discharge orifice positioned between the first and second pressure chambers and the propellant gas initially flows into the first pressure chamber, said propellant gas discharge system comprises a tubular casing mounted in a closed end part of the guide tube and a tubular discharge portion that extends in an axial longitudinal direction into a recess, forming the first pressure chamber, in the step piston and is sealed at its periphery against internal face of the recess;a closure cap mounted in the closed end part of the tubular casing, the closure cap having an ignition system, wherein the ignition system penetrates into the closure cap through an orifice in the closure cap; andthe step piston which is set into motion by the propellant gas acting in the first pressure chamber clears the discharge orifice into the second pressure chamber after covering a first distance so that the propellant gas flowing into the second pressure chamber and acting therein to additionally drive the step piston.