Air bag with tearable and non-tearable tethers

• US 5,678,858 A
• Filed: 01/16/1996
• Issued: 10/21/1997
• Est. Priority Date: 01/23/1995
• Status: Expired due to Fees

• Current Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Nakayama, Yoshikazu, Yoshida, Junichi, Chikaraishi, Tsuneo
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): English, Peter C.
• Application Number:
  US08/585,870
• Time in Patent Office: 644 Days
• Field of Search: 280/743.2, 280/743.1, 280/731, 280/728.1, 280/728.2, 280/729, 280/730.1, 280/732
• US Class Current: 280/743.2
• CPC Class Codes: B60R 2021/23382 Internal tether means
• CPC Class Codes: B60R 21/217 Inflation fluid source retainers, e.g. reaction canisters; Connection of bags, covers, diffusers or inflation fluid sources therewith or together
• CPC Class Codes: B60R 21/233 comprising a plurality of individual compartments; comprising two or more bag-like members, one within the other B60R21/232 takes precedence
• CPC Class Codes: B60R 21/2338 Tethers
• CPC Class Codes: B60R 21/2342 Tear seams

Abstract

An air bag includes a main body formed by sewing up the respective peripheries of two fabrics, a front panel and a rear panel with a thread, first tether belts and second tether belts for connecting the central portion of the front panel and the central portion of the rear panel. Each of the first tether belts has a low strength portion structured by forming notches on both sides. Stud bolts are inserted into through holes of the first tether belts, through holes of the air bag, bolt holes of the retainer, and bolt holes of a flange. The air bag deploys to the outside of the steering wheel quite rapidly in the initial stage of the deployment, and the front panel extends suitably forward in the latter stage of the deployment.

Claims

1. An air bag adapted to be mounted on a steering wheel by means of mounting members and a retainer, comprising:

a main body made of fabrics and formed of a front panel and a rear panel connected together at peripheries thereof by sewing,

an inflator receiving opening formed in said rear panel,

through holes formed around said inflator receiving opening of said main body, through which said mounting members are adapted to be inserted for connecting the air bag to the retainer attached to the steering wheel,

at least one first tether belt made of fabrics and having a first end and a second end, said first end being connected to said front panel by sewing, and the second end being not sewn to said front panel and said rear panel and having at least one through hole through which one of said mounting members is adapted to be inserted, the length (L₁) from said through hole to a connected portion to said front panel being at most 150 mm,

a low strength portion formed in said first tether belt for allowing said first tether belt to be torn after at least a part of said main body is adapted to deploy to an outside of the steering wheel, and

at least one second tether belt made of fabrics and having a third end and a fourth end, said third end being connected to said front panel by sewing, and the fourth end being connected to said rear panel by sewing, the length (L₂) between connected portions to said front and rear panels being at least 50 mm longer than the length (L₁), said second tether belt having a strength not to be torn and to connect the front panel and rear panel even after said main body is fully deployed.

2. An air bag as claimed in claim 1, wherein the length (L₁) of said first tether belt is at most 100 mm, and the length (L₂) of said second tether belt is at least 50 mm longer than the length (L₁).

3. An air bag as claimed in claim 1, said second end of the first tether belt has a plurality of said through holes spaced apart from each other in the longitudinal direction of said first tether belt, and the length (L₁) is the length between the through hole nearest to the connected portion to the front panel and said connected portion.

4. An air bag mounting structure for a steering wheel comprising:

an air bag including;

a main body made of fabrics and formed of a front panel and a rear panel connected together at peripheries thereof by sewing,

an inflator receiving opening formed in said rear panel,

through holes formed around said inflator receiving opening of said main body,

at least one first tether belt made of fabrics and having a first end and a second end, said first end being connected to said front panel by sewing, and said second end being not sewn to the front and rear panels and having at least one through hole, the length (L₁) from said through hole to a connected portion to said front panel being at most 150 mm,

a low strength portion formed in said first tether belt for allowing said first tether belt to be torn after at least a part of said main body is adapted to deploy to an outside of the steering wheel, and

at least one second tether belt made of fabrics and having a third end and a fourth end, said third end being connected to said front panel by sewing, and the fourth end being connected to said rear panel by sewing, the length (L₂) between connected portions to said front and rear panels being at least 50 mm longer than the length (L₁), said second tether belt having a strength not to be torn and to connect the front panel and rear panel even after said main body is fully deployed;

a retainer having an inflator mounting opening and mounting member receiving holes disposed around a periphery of said inflator mounting opening, said retainer being adapted to be attached to the steering wheel;

a ring disposed inside said air bag and having mounting members protruding from said ring, said mounting members being inserted into the respective through holes of said air bag and said retainer and said at least one through hole of said first tether belt so that a peripheral portion of said inflator receiving opening of said air bag is clamped between the ring and the retainer and the first tether belt is connect to the retainer.