Emergency locking retractor for vehicle seat belts

• US 4,057,200 A
• Filed: 07/09/1976
• Issued: 11/08/1977
• Est. Priority Date: 06/01/1974
• Status: Expired due to Term

• Current Assignee: Susumu Ubukata
• Original Assignee: Susumu Ubukata
• Inventors: Oda, Kenji, Ubukata, Susumu, Iyoda, Shozo
• Primary Examiner(s): Gilreath, Stanley N.
• Assistant Examiner(s): Jillions, John M.
• Application Number:
  US05/704,104
• Time in Patent Office: 487 Days
• Field of Search: 242/107.4 R-107.4 E, 297/388, 280/744-747
• US Class Current: 242/384.6
• CPC Class Codes: B60R 22/40 responsive only to vehicle movement

Abstract

A seat belt retractor incorporates a fail-safe locking mechanism that is actuated by vehicle acceleration to lock a retractor drum against rotation in the belt unwinding direction. A pair of locking wheels are arranged coaxially with the drum for simultaneous rotation therewith, and a detent movable into and out of engagement with both locking wheels is biased, by biasing means such as a spring, into engagement therewith. Normally, the detent is restrained from engagement with the locking wheels against the force of the biasing means by an actuator associated with an inertial element constituting a part of acceleration sensing means. Upon displacement of the inertial element from its normal position of rest, the actuator permits the detent to move into engagement with the locking wheels by the force of the biasing means.

Claims

1. An emergency locking retractor for a seat belt of a vehicle comprising, in combination:

a frame adapted to be secured to the vehicle;

a drum rotatably supported by said frame and having one end of the belt anchored thereto for winding and unwinding the same, said drum having an axis of rotation oriented at an angle other than zero relative to the horizontal;

first biasing means for causing said drum to rotate in the belt winding direction;

a locking wheel rotatable in unison with said drum;

detent means pivotable about an axis parallel to the axis of drum rotation between an operative position where said detent means engages said locking wheel to lock said drum against rotation in the belt unwinding direction, and an inoperative position where said detent means is disengaged from said locking wheel;

second biasing means for biasing said detent means from the inoperative toward the operative position;

acceleration sensing means including an inertial element normally held in a predetermined position so as to be displaceable relative to said frame in response to acceleration of the vehicle; and

actuator means interposed between said sensing means and said detent means and having a first end disposed under said inertial element to be urged downwardly thereby, and a second end disposed for abutting contact with said detent means to hold the latter in the inoperative position against the bias of said second biasing means;

said actuator means including a mechanism for converting upward displacement of said first end in response to displacement of said inertial element into a displacement of said second end in a direction which is substantially the direction from the inoperative toward the operative position of said detent means and which is different from that of the displacement of said first end, whereby upon displacement of said first end, said second end permits said detent means to move from the inoperative to the operative position under the bias of said second biasing means.

2. The retractor as defined in claim 1, wherein the axis of drum rotation is oriented vertically.

3. The retractor as defined in claim 1, wherein said sensing means includes a housing having a substantially spherical internal surface with a circular aperture located centrally at its bottom, said inertial element is a spherical ball displaceably mounted within said housing, and said aperture has a smaller diameter than said inertial element, whereby the latter rests normally over said aperture.

4. The retractor as defined in claim 3, further comprising stop means supporting thereon said first end of the actuator means to determine the normal position of said first end in such a manner that said inertial element normally rides freely on said first end, with a clearance between said inertial element and an edge of said housing bounding said aperture.

5. The retractor as defined in claim 1, wherein said actuator means is in the form of a pivotable bell crank having two mutually angularly disposed arms, and said first and said second ends are on said arms, respectively.

6. The retractor as defined in claim 5, wherein said sensing means further includes a housing having a substantially spherical internal surface with a circular aperture located centrally at its bottom, said inertial element is a spherical ball displaceably mounted within said housing, and the latter is rigidly mounted on said frame and has means pivotally supporting said bell crank.