Seat belt retractor

1. A seatbelt retractor for a seat belt device in a vehicle, the retractor comprising:

a frame;

a spool 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 at both ends to the frame and configured to rotate in a webbing extraction direction and a webbing retraction direction;

a pretensioner device configured to rotate the spool in a webbing retraction direction when the pretensioner device activates in response to an acceleration of the vehicle greater than a predetermined high acceleration; and

wherein the pretensioner device comprises a power transmission element carried in a pretensioner tube that is driven by a piston located in the pretensioner tube when the pretensioner device is activated so that the power transmission element can contact a ring gear connected to the spool to thereby rotate the spool in the webbing retraction direction;

wherein the pretensioner device includes a gas generator that is configured to create operating gas for driving the piston into the power transmission element;

and wherein the pretensioner device includes a seal system that includes a stopper tube located in a downstream end of the pretensioner tube to create a stop location for the piston to prevent operating gas from the gas generator from exiting the end of the pretensioner tube; and further including

a guide block located in the downstream end of the pretensioner tube for directing the power transmission element into the ring gear; and wherein the guide block includes a trench disposed on an underside of the guide block, and wherein the trench is configured to engage a projection connected to the frame of the retractor.

2. The seat belt retractor of claim 1 , wherein the guide block includes a flange which blocks the downstream end of the stopper tube.

3. The seat belt retractor of claim 1 , wherein the guide block includes a groove for receiving a stopper pin.

4. The seat belt retractor of claim 1 , wherein the projection extends from the frame of the retractor and extends through a slot in the pretensioner tube and through a slot in the stopper tube and into the guide block trench to hold and engage the stopper tube and prevent the stopper tube from moving downstream when the pretensioner device activates.

5. A seatbelt retractor for a seat belt device in a vehicle, the retractor comprising: a frame; a spool 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 at both ends to the frame and configured to rotate in a webbing extraction direction and a webbing retraction direction; a pretensioner device configured to rotate the spool in a webbing retraction direction when the pretensioner device activates in response to an acceleration of the vehicle greater than a predetermined high acceleration; and wherein the pretensioner device comprises a power transmission element carried in a pretensioner tube that is driven by gas provided by a gas generator when the pretensioner device is activated so that the power transmission element can contact a ring gear connected to the spool to thereby rotate the spool in the webbing retraction direction; and a stopper tube located in a downstream end of the pretensioner tube to create a stop location for a sealing element to prevent operating gas from the gas generator from exiting the end of the pretensioner tube; wherein the pretensioner device further includes a guide block located on the stopper tube for directing the power transmission element into the ring gear, and the guide block is connected to the pretensioner tube by a pin that passes through the guide block and the pretensioner tube.

6. The retractor of claim 5 , wherein the guide block includes a flange that projects outwardly to block downstream movement of the stopper tube.

7. The retractor of claim 5 , wherein the stopper tube includes an opening for receiving a projection of the guide block to thereby fix the position of the stopper tube relative to the guide block and the pretensioner tube.

8. A seatbelt retractor for a seat belt device in a vehicle, the retractor comprising:

a frame;

a spool 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 at both ends to the frame and configured to rotate in a webbing extraction direction and a webbing retraction direction;

a pretensioner device configured to rotate the spool in a webbing retraction direction when the pretensioner device activates in response to an acceleration of the vehicle greater than a predetermined high acceleration; and

wherein the pretensioner device comprises a power transmission element carried in a pretensioner tube that is driven by gas provided by a gas generator when the pretensioner device is activated so that the power transmission element can contact a ring gear connected to the spool to thereby rotate the spool in the webbing retraction direction;

and a stopper tube located in a downstream end of the pretensioner tube to create a stop location for a sealing element to prevent operating gas from the gas generator from exiting the end of the pretensioner tube;

wherein the stopper tube is fixed to the frame to thereby prevent downstream movement of the stopper tube relative to the pretensioner tube; and

wherein the stopper tube includes a slot and wherein the frame includes a flange that projects through the slot to fix the position of the stopper tube relative to the frame.

9. The seat belt retractor of claim 8 , further comprising a guide block located within the stopper tube and in the downstream end of the pretensioner tube for directing the power transmission element into the ring gear; and wherein the guide block is fixed in position relative to the pretensioner tube.