Seat belt pretensioner

• US 6,419,177 B2
• Filed: 02/05/2001
• Issued: 07/16/2002
• Est. Priority Date: 02/04/2000
• Status: Expired due to Fees

• Current Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Stevens, Bruce A.
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US09/777,388
• Publication Number:
  US 20010030254A1
• Time in Patent Office: 526 Days
• Field of Search: 242/374, 280/806, 297/478, 297/480
• US Class Current: 242/374
• CPC Class Codes: B60R 2022/468 characterised by clutching means between actuator and belt reel
• CPC Class Codes: B60R 22/4619 Transmission of tensioning power by cable, e.g. using a clutch on reel side
• CPC Class Codes: B60R 22/4628 characterised by fluid actuators, e.g. pyrotechnic gas generators actuating a cable B60R22/4619
• CPC Class Codes: B60R 22/4633 Linear actuators, e.g. comprising a piston moving along reel axis and rotating along its own axis

Abstract

A pretensioner 10 for a seat belt 12 utilizes a strap 34 coiled about a clutch assembly 46 wherein the clutch assembly 46 is in normal operation of a vehicle, rotatable about a portion of a webbing reel shaft 16. The pretensioner 10 contains a first passage 20 and a second passage 22 for the respective containment of the clutch assembly 46 and an actuator 32, wherein each passage is formed perpendicular and in volumetric intersection with the other. The pretensioner 10 also contains a gas generant composition 30 in combustive communication with the actuator 32. Upon ignition, the gas pressure produced by the pyrotechnic 30 propels the actuator 32 into the strap 34, thereby effecting rotary advancement of the clutch assembly 46 and the shaft 16, and thus pretensioning the seat belt 12 wound about a spool 13 of a seat belt retractor 14, wherein the spool 13 is rotatably engaged with a second portion of the shaft 16 and thus provided in coaxial relation with the clutch assembly 46.

Claims

1. A pretensioner cooperating with a webbing reel shaft of a seatbelt retractor webbing reel, that upon activation pretensions the seatbelt webbing associated therewith, the pretensioner comprising:

a housing having a first circular cylindrical passage volumetrically intersecting a second rectangular cylindrical passage, said passages formed perpendicular to each other, wherein said shaft extends through said first passage and said second passage has a first end and a second end, the second end extending across and past the diameter of the first passage;

a clutch assembly fixed within the first passage wherein said webbing reel shaft axially extends through said clutch assembly;

a strap having a first end fixed to said housing, a portion extending across a section of said second passage, and a second end coiled about and fixed to said clutch assembly;

an actuator positioned within the first end of said second passage for tensioning said strap upon pretensioner activation; and

a gas generant composition, ignitable to release sufficient force to drive the actuator through said second passage to the second end thereof, thereby effecting a tensioning of the strap and a peripheral force about the clutch assembly, and then a simultaneous rotary advancement of the clutch assembly, the webbing reel shaft, and the webbing reel, and thus winding the reel and tensioning the seatbelt webbing thereon.

2. The pretensioner of claim 1 wherein said actuator is a one-piece piston.

3. The pretensioner of claim 1 wherein said actuator contains a gas generant composition and thereby also functions as a gas generator.

4. The pretensioner of claim 1 further comprising a resilient cylindrical liner extending up to the circumference but not within the diameter of the first passage, for strengthening the first end of the second passage.

5. The pretensioner of claim 1 further comprising a gas generator for containment of the gas generant composition.

6. A pretensioner cooperating with a webbing reel shaft of a seatbelt retractor webbing reel, that upon activation pretensions the seatbelt webbing associated therewith, the pretensioner comprising:

a housing having a first circular cylindrical passage volumetrically intersecting a second rectangular cylindrical passage, said passages formed perpendicular to each other, wherein said shaft extends through said first passage and said second passage has an open first end and a second end, the second end extending across and past the diameter of the first passage;

a resilient cylindrical sleeve having a closed first end and an open second end, wherein the second end of the sleeve is fixed to and axially aligned with the first end of the second cylindrical passage;

a clutch assembly fixed within the first passage wherein said webbing reel shaft axially extends through said clutch assembly;

a strap having a first end fixed to said housing, a flat portion extending across a section of said second passage, and a second end coiled about and fixed to said clutch assembly;

an actuator positioned within said circular cylindrical sleeve for acting upon the flat portion of the strap and tensioning said strap upon pretensioner activation;

a gas generant composition positioned intermediate of the actuator and the first end of said cylindrical sleeve; and

an initiator fixed within the first end of said cylindrical sleeve for igniting said gas generant composition and closing the first end of the cylindrical sleeve,

wherein upon receipt of a signal to the initiator, the gas generant composition is ignited to release sufficient force to drive the actuator through said cylindrical sleeve and through said second passage to the second end thereof, thereby effecting a tensioning of the strap and actuation of the clutch assembly, and then a simultaneous rotary advancement of the clutch assembly, the webbing reel shaft, and the webbing reel, thus winding the reel and tensioning the seatbelt webbing thereon.

7. A pretensioner cooperating with a webbing reel shaft of a seatbelt retractor webbing reel, that upon activation pretensions the seatbelt webbing associated therewith, the pretensioner comprising:

a housing having a first passage volumetrically intersecting a second linear passage, said passages formed perpendicular to each other, wherein said shaft extends through said first passage and said second passage has a first end and a second end, the second end extending across and past the diameter of the first passage;

a clutch assembly fixed within the first passage wherein said webbing reel shaft axially extends through said clutch assembly;

a strap having a first end fixed to said housing, a portion extending across a section of said second passage, and a second end coiled about and fixed to said clutch assembly;

an actuator positioned within the first end of said second passage for tensioning said strap upon pretensioner activation; and

a gas generant composition, ignitable to release sufficient force to drive the actuator through said second passage to the second end thereof, thereby effecting a tensioning of the strap and a peripheral force about the clutch assembly, and then a simultaneous rotary advancement of the clutch assembly, the webbing reel shaft, and the webbing reel, and thus winding the reel and tensioning the seatbelt webbing thereon.

8. A pretensioner cooperating with a webbing reel shaft of a seatbelt retractor webbing reel, that upon activation pretensions the seatbelt webbing associated therewith, the pretensioner comprising:

a housing having a first passage volumetrically intersecting a second linear passage, said passages formed perpendicular to each other, wherein said shaft extends through said first passage and said second passage has an open first end and a second end, the second end extending across and past the diameter of the first passage;

a resilient cylindrical sleeve having a closed first end and an open second end, wherein the second end of the sleeve is fixed to and axially aligned with the first end of the second linear passage;

a clutch assembly fixed within the first passage wherein said webbing reel shaft axially extends through said clutch assembly;

a strap having a first end fixed to said housing, a flat portion extending across a section of said second passage, and a second end coiled about and fixed to said clutch assembly;

an actuator positioned within said cylindrical sleeve for acting upon the flat portion of the strap and tensioning said strap upon pretensioner activation;

a gas generant composition positioned intermediate of the actuator and the first end of said cylindrical sleeve; and

an initiator fixed within the first end of said cylindrical sleeve for igniting said gas generant composition and closing the first end of the cylindrical sleeve,

wherein upon receipt of a signal to the initiator, the gas generant composition is ignited to release sufficient force to drive the actuator through said cylindrical sleeve and through said second passage to the second end thereof, thereby effecting a tensioning of the strap and actuation of the clutch assembly, and then a simultaneous rotary advancement of the clutch assembly, the webbing reel shaft, and the webbing reel, thus winding the reel and tensioning the seatbelt webbing thereon.