Seat belt pretensioner

A seat belt pretensioner for a seat belt device in a vehicle, the pretensioner comprising:

• a frame;
• a ball housing attached to the frame;
• a drive wheel located within the ball housing;
• a spool rotationally locked to the drive wheel and configured to be fixed to one end of a webbing so that the webbing may be wound around the spool, the spool being rotatably mounted to the frame and configured to rotate in a pretensioning direction in response to an acceleration of the vehicle greater than a predetermined high acceleration;
• a first ratchet wheel disposed adjacent to the spool and located at a first end of the spool;
• a pawl attached to the frame is configured to engage the first ratchet wheel;
• at least one ball shaped power transmission element carried in a pipe that is driven by gas provided from a gas generator when the pretensioner device is activated so that the at least one power transmission element can contact the drive wheel to thereby rotate the spool in the pretensioning direction;
• and
• wherein the first ratchet wheel is configured to engage the pawl when the webbing is pulled in an engagement direction, wherein the engagement direction is opposite of the pretensioning direction.

A pretensioner for a seat belt device in a vehicle, the pretensioner comprising:

• a frame;
• a ball housing attached to the frame;
• a drive wheel located within the ball housing;
• a rotating spool connected to the drive wheel and configured to be fixed to one end of a seat belt webbing so that the webbing may be wound around the spool, the spool being rotatably mounted to the frame and configured to rotate in a pretensioning direction in response to an acceleration of the vehicle greater than a predetermined high acceleration;
• a pipe connected to the ball housing;
• a gas generator connected to the pipe;
• at least one ball shaped power transmission element carried in the pipe that is driven by gas provided from the gas generator when the pretensioner device is activated so that the at least one power transmission element can contact the drive wheel to thereby rotate the spool to retract the seat belt;
• wherein at least one seal member is located between the at least one power transmission element and the gas generator, wherein the seal member is configured to travel through the pipe after the pretensioner device is activated and is sized to plug the pipe at an inlet to the ball housing.