Pretensioner integrated with a force transferring apparatus of a seat belt retractor

• US 6,513,747 B1
• Filed: 08/08/2000
• Issued: 02/04/2003
• Est. Priority Date: 06/22/2000
• Status: Expired due to Fees

• Current Assignee: Delphi Automotive Systems Sungwoo Corp. (Aptiv PLC)
• Original Assignee: Delphi Automotive Systems Sungwoo Corp. (Aptiv PLC)
• Inventors: Jin, Sung-woo, Kim, Seung-man, Lee, Jong-hoon
• Primary Examiner(s): NGUYEN, JOHN QUOC
• Application Number:
  US09/633,971
• Time in Patent Office: 910 Days
• Field of Search: 242/374, 280/806, 280/807, 297/476, 297/477, 297/478
• US Class Current: 242/374
• CPC Class Codes: B60R 2022/1818 Belt guides
• 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

Abstract

A pretensioner comprises a pyrotechnic force generating device including a horizontal tube with a propellent charged cartridge, a housing receiving one end of the cylinder with the horizontal tube being supported to cooperate with the force generating device in order to reverse-rotate the reel; a force transmitting portion including an arm positioned in a first chamber of the housing, one end of which is directed to the piston in the cylinder and the other end of which is extended out of the cylinder, a pulley rotatably mounted on the other branched end of the arm and a cable fixed at one end to the housing, passed through the pulley, wound around the clutch disk and fixed at the other end to the clutch disk; and a pretensioner positioned in a second chamber, which comprises the clutch disk and a clutch portion, in which the clutch disk includes a circular groove formed around the periphery thereof to allow a length of the cable to be wound thereon, a plurality of second coupling projections each having a right-angled surface toward one direction and a slanted surface toward the other direction, at least three of coupling grooves cut out at one side in a right-angle and at the other side in a slant angle and a first fixing groove formed to fix the other end of the cable, and the clutch portion includes at least three of first coupling projections forming a slanted surface at one side and a right-angled surface at other side for cooperating with the coupling grooves and a plurality of third coupling projections or concaved grooves formed at the positions facing to the second coupling projections on one side surface of the reel.

Claims

1. A safety belt retractor including a reel rotatably mounted on an U-shaped bracket to perform the webbing operating of a safety belt, a locking portion for restraining the rotating of the reel cooperating with a ratchet gear formed on one side of the reel in an abnormal state of a vehicle, a spring portion including a spring of a clock spring type mounted on the other side of the reel to enable the reel to wind the belt thereon and a pretensioner mounted between the inner surface of the spring portion and the U-shaped bracket to reverse-rotate the reel and then withdraw a predetermined length of the safety belt by the force generated in a gas generating apparatus;

comprises

a pyrotechnic force generating means including a horizontal tube with a propellent charge cartridge mounted therein, a cylinder vertically extended from the other side of the horizontal tube and a piston movably mounted in the cylinder;

a housing receiving one end of the cylinder with the horizontal tube being supported on the U-shaped bracket to cooperate with the force generating means in order to reverse-rotate the reel upon the force generating;

a force transmitting portion including an arm positioned in a first chamber of the housing, one end of which is directed to the piston in the cylinder and the other end of which is extended out of the cylinder, a pulley rotatably mounted on axes of the other branched end of the arm and a cable fixed at one end to a predetermined position of the housing, passed through the pulley, wound around a clutch disk by a predetermined turn and fixed at the other end to a predetermined position of the clutch disk; and

a pretensioner positioned in a second chamber adjacent to the first chamber, which comprises the clutch disk and a clutch portion, in which the clutch disk includes a circular groove formed around the periphery thereof to allow a predetermined length of the cable to be wound thereon, a plurality of the second coupling projections each having a right-angled surface toward one direction and a slanted surface toward the other direction adjacent to the periphery of one side surface thereof, at least three of coupling grooves each cut out at one side in a right-angle and at the other side in a slant angle and a first fixing groove formed to fix the other end of the cable, and the clutch portion includes at least three of first coupling projections each forming a slanted surface at one side and a right-angled surface at other side for cooperating with the coupling grooves to allow the clutch disk to be reversely rotated and a plurality of third coupling projections or concaved grooves formed at the positions facing to the second coupling projections on one side surface of the reel for coupling with the second coupling projections.

2. The pretensioner integrated with the pyrotechnic gas generating apparatus according to claim 1, in which:

at least three of the first coupling projections in the second chamber are positioned at different arc angles α

, β

, γ

to be staggered from one another properly dividing the circumferential angle of 360°

so that they are respectively inserted into preferable insertion position of the coupling grooves.

3. The pretensioner integrated with the pyrotechnic gas generating apparatus according to claim 1, in which:

a small bearing and a pin are used to mount the pulley on the arm to freely rotate the pulley, thereby minimizing the friction of the cable on the pulley.

4. The pretensioner integrated with the pyrotechnic gas generating apparatus according to claim 1, in which:

a weight is provided on the pulley to have an eccentricity so that the weight center of the pulley is slightly inclined toward one direction.

5. The pretensioner integrated with the pyrotechnic gas generating apparatus according to claim 1, in which:

supporting grooves are formed on both sides of the pulley and supporting bars are fixed to positions corresponding to at least one predetermined length of the cable, thereby securing the exact traveling length of the cable.

6. The pretensioner integrated with the pyrotechnic gas generating apparatus according to claim 1, in which:

the safety belt retractor further comprises a guider for guiding the safety belt being wound on or released from the reel, thereby smoothing the webbing due to the reverse-rotating of the reel upon the operating of the pretensioner.