| 摘要 |
PURPOSE: To provide a belt pretensioner of an automobile, which can pivotally move a housing block without being disturbed by a cable. CONSTITUTION: A belt pretensioner provided with a pyrotechnical piston/cylinder drive has a mass for detecting an automobile including a pivotally attached housing block 14, a gas generator 18 and a piston/cylinder 20. In order to ensure pivot movement of the housing block 14, a piston 24 is housed in a cylinder 22 while having axial and radial clearance. The piston 24 is provided with an annular groove 50 and an annular seal 52 is arranged therein. While no gas pressure is exerted, the annular seal 52 is out of contact with the inner wall of the cylinder 22. However when the gas pressure is exerted, this seal is raised along the conical rising bottom of the annular groove 50, simultaneously expanded, sealed and engaged with the inner wall. |
