Abstract: Provided is a compact power actuator which is simple in structure, reliable in operation, and easy to install. The power actuator comprises a piston assembly which is received in a fixed cylinder for either directly or indirectly engaging a driven member, and a propellant for rapidly increasing the inner pressure of the cylinder to push the piston assembly outward so that the driven member may be instantaneously driven. A spring is interposed between the piston assembly and the propellant to urge the piston assembly in the projecting direction. The front end of the propellant fits into the central opening so that the available space may be fully utilized. Therefore, the size of the power actuator can be reduced, and the required amount of the pyrotechnic material for the propellant can be reduced due to the reduced initial volume of the chamber for the expansion of the generated gas.

Abstract: Provided is an anti-submarine vehicle seat device which can reliably prevent submarining without complicating the assembling of the seat assembly, and is adapted to be retrofitted. Major parts of the device are incorporated into a subassembly which comprises a casing adapted to be attached to a seat frame, a power actuator fixedly secured in the casing, an arm pivotally supported by the casing, and adapted to be actuated by the power actuator, and a lock mechanism for keeping the arm substantially at an actuated position once the arm is actuated by the power actuator.

Abstract: Provided is a compact power actuator which is simple in structure, reliable in operation, and easy to install. The power actuator comprises a piston assembly which is received in a fixed cylinder for either directly or indirectly engaging a driven member, and a propellant for rapidly increasing the inner pressure of the cylinder to push the piston assembly outward so that the driven member may be instantaneously driven. A spring is interposed between the piston assembly and the propellant to urge the piston assembly in the projecting direction. The front end of the propellant fits into the central opening so that the available space may be filly utilized. Therefore, the size of the power actuator can be reduced, and the required amount of the pyrotechnic material for the propellant can be reduced due to the reduced initial volume of the chamber for the expansion of the generated gas.

Abstract: Provided is a vehicle occupant restraint system which can reduce the load on the chest and head of the vehicle occupant in an impact situation while reliably preventing the submarine phenomenon. By restraining the pelvis and the adjacent parts of the vehicle occupant before the load is applied to the chest and head, the load is more favorably distributed, and the critical parts are favorably protected. This can be accomplished by activating a restraining member for raising an appropriate part of the vehicle seat immediate upon detecting an impact.

Abstract: Provided is a compact power actuator which is simple in structure, reliable in operation, and easy to install. The power actuator comprises a piston assembly which is received in a fixed cylinder for either directly or indirectly engaging a vehicle occupant restraint member, and a propellant for rapidly increasing the inner pressure of the cylinder to push the piston assembly outward so that the restraint member may be instantaneously driven. A spring is interposed between the piston assembly and the propellant to urge the piston assembly in the projecting direction. The front end of the propellant fits into the central opening so that the available space may be fully utilized. Therefore, the size of the power actuator can be reduced, and the required amount of the pyrotechnic material for the propellant can be reduced due to the reduced initial volume of the chamber for the expansion of the generated gas.

Abstract: Provided is a compact power actuator which is simple in structure, reliable in operation, and easy to install. The power actuator comprises a piston assembly which is received in a fixed cylinder for either directly or indirectly engaging a vehicle occupant restraint member, and a propellant for rapidly increasing the inner pressure of the cylinder to push the piston assembly outward so that the restraint member may be instantaneously driven. A spring is interposed between the piston assembly and the propellant to urge the piston assembly in the projecting direction. The front end of the propellant fits into the central opening so that the available space may be fully utilized. Therefore, the size of the power actuator can be reduced, and the required amount of the pyrotechnic material for the propellant can be reduced due to the reduced initial volume of the chamber for the expansion of the generated gas.

Abstract: Provided is a vehicle seat device equipped with an anti-submarine vehicle seat device for preventing submarine at the time of an impact without increasing the size and weight of the seat assembly. The casing and/or the restraint member serve the dual purposes as structural members for the seat frame so that the overall amount of the material for the structural members can be reduced.

Abstract: Provided is a vehicle occupant restraint system which can reduce the load on the chest and head of the vehicle occupant in an impact situation while reliably preventing the submarine phenomenon. By restraining the pelvis and the adjacent parts of the vehicle occupant before the load is applied to the chest and head, the load is more favorably distributed, and the critical parts are favorably protected. This can be accomplished by activating a restraining member for raising an appropriate part of the vehicle seat immediate upon detecting an impact.