Patent ID: 7717367

Claim:
A pretensioner device comprising: a take up shaft; a cylindrical portion provided coaxially and integrally with one side in the axial direction of said take-up shaft at which a webbing for restraining a vehicle occupant is taken-up and pulled-out, the cylindrical portion being open toward an outer side; a piston provided at one side in the axial direction of the cylindrical portion, and moving due to operation of a gas generating means in an emergency; a rotating body which is disposed relatively rotatably at the cylindrical portion and at whose outer peripheral portion a plurality of engaging teeth are formed, the rotating body being rotated in a webbing take-up direction due to the piston moving; and a substantially flat clutch plate having a plurality of meshing claws which are connected together integrally and which respectively fit-together with valley portions of the plurality of engaging teeth of the rotating body, and when the rotating body rotates relatively to the clutch plate in the webbing take-up direction, the plurality of meshing claws are guided by the plurality of engaging teeth, and deform outwardly, and engage an inner peripheral surface of the cylindrical portion, wherein the engaging teeth of the rotating body have first projections which project-out in a peripheral direction of the rotating body, each of said projections having a side surface; the meshing claws of the clutch plate have second projections which project-out axially from the clutch plate and in the peripheral direction of the rotating body and whose end surfaces, at one side in an axial direction of the rotating body, are offset from a plane of said clutch plate and face the first projections, and wherein the end surfaces of the second projections engage with the side surfaces of the first projections so that, movement of the clutch plate in an axial direction with respect to the rotating body is restricted.