Restraint web pre-tensioning and suspension seat pull-down device

A device for pulling down a seat portion of a motor vehicle seat toward a seat base coupled to a support structure of a motor vehicle, the seat portion suspended above the seat base, the device comprising:

• an elongated housing configured to be secured to the suspended seat portion of the motor vehicle seat,
• a web having a first end fixed to the suspended seat portion and second end, opposite the first end, configured to be secured to one of the seat base and the support structure to which the seat base is coupled,
• an elongated piston carried by the housing and defining a web guide at one end thereof in contact with the web between the first and second ends of the web, the piston moving along and relative to the housing in response to actuation thereof, the web guide of the moving piston displacing the web within the housing to pull the suspended seat portion toward the seat base,
• an elongated tube carried by the housing, the elongated tube having an open end and a closed end opposite the open end thereof, the tube sized to receive the elongated piston longitudinally therein via the open end of the tube,
• a seal disposed about the elongated piston, and
• an airtight space defined within the tube between the closed end thereof and the seal disposed about the elongated piston,
• wherein the elongated piston contains pressurized gas and defines an orifice at an end thereof opposite the end defining the web guide, the orifice open to the space defined within the tube,
• and wherein the device further comprises an actuator responsive to an activation signal to cause the piston to expel the pressurized gas from the orifice into the space to thereby force the piston out of the tube.

A system for pre-tensioning a motor vehicle occupant restraint harness, the system comprising:

• a motor vehicle seat having a seat portion coupled to a seat base, the seat base configured to be mounted to a support structure within a motor vehicle,
• an occupant restraint harness coupled to the motor vehicle seat,
• an elongated housing secured to the seat portion of the motor vehicle seat,
• a web having a first end extending into the housing and coupled to the restraint harness and second end, opposite the first end, secured to one of the seat base and the support structure,
• a piston carried by the housing and having a web guide in contact with the web between the first and second ends of the web,
• an actuator responsive to an activation signal to actuate the piston to cause the piston and web guide to move within and relative to the housing to pre-tension the occupant restraint harness by displacing the web,
• a sensor configured to produce one of a roll signal and an impact signal,
• a processor,
• a memory unit having instructions stored therein which, when executed by the processor, cause the processor to process the one of the roll signal and the impact signal and to produce the activation signal if the corresponding one of the roll signal indicates an imminent roll condition of the motor vehicle and the impact signal indicates an imminent impact of the motor vehicle,
• an elongated tube carried by the housing, the elongated tube having an open end and a closed end opposite the open end thereof, the tube sized to receive the elongated piston longitudinally therein via the open end of the tube,
• a seal disposed about the elongated piston, and
• an airtight space defined within the tube between the closed end thereof and the seal disposed about the elongated piston,
• wherein the elongated piston contains pressurized gas and defines an orifice at an end thereof opposite the end defining the web guide, the orifice open to the space defined within the tube,
• and wherein the actuator is responsive to the activation signal to cause the piston to expel the pressurized gas from the orifice into the space to thereby force the piston out of the tube.