Cover for an airbag unit and the process for producing it

• US 5,180,187 A
• Filed: 07/18/1991
• Issued: 01/19/1993
• Est. Priority Date: 02/18/1989
• Status: Expired due to Term

• Current Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler-Benz AG (Mercedes-Benz Group AG)
• Inventors: Muller, Manfred, Bossenmaier, Alban, Katz, Egon, Henseler, Wolfgang, Hamm, Dietrich
• Primary Examiner(s): Rice, Kenneth R.
• Application Number:
  US07/731,974
• Time in Patent Office: 551 Days
• Field of Search: 280/728, 280/730, 280/731, 280/732, 280/743
• US Class Current: 280/732
• CPC Class Codes: B29C 37/0057 Moulding single grooves or ribs, e.g. tear lines folding lines B29C53/06
• CPC Class Codes: B29C 44/146 Shaping the lining before foaming
• CPC Class Codes: B29C 51/00 Shaping by thermoforming , i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor blow moulding of tubular preforms B29C49/00, deforming of tubular or hollow preforms B29C67/0014
• CPC Class Codes: B29C 53/06 Forming folding lines by pressing or scoring
• CPC Class Codes: B29C 59/007 Forming single grooves or ribs, e.g. tear lines, weak spots by moulding B29C37/0057; folding lines B29C53/06; in metal articles B21D17/00; by cutting B26D3/08
• CPC Class Codes: B29L 2031/3038 Air bag covers
• CPC Class Codes: B60R 21/2165 characterised by a tear line for defining a deployment opening

Abstract

The application is concerned with a cover of an airbag unit in a motor vehicle which is equipped with a tear-open line and has a foam-backed foil and the process for making the cover. The process includes:

a) heating a foil in the region of the intended tear-open line;

b) forming a channel in the foil which is drawn-in in relation to the adjoining face of the foil in the region of the tear-open line;

c) creating a reduction in wall thickness of the foil at the tear-open line, located at a channel bottom, by high-frequency embossing;

d) introducing the foil into a mold and foam backing the foil;

e) producing a smaller wall thickness in the foam backing in the region of the tear-open line.

Claims

1. A cover for an airbag unit having a tear line, comprising:

a foil layer, having an outer surface, an inner surface, and a foil wall thickness, including a substantially U-shaped channel formed in said foil layer by heating and deep drawing said foil layer in the region of the tear line, said U-shaped channel having an open end on said outer surface and a bottom channel surface, said foil wall thickness being reduced at said bottom channel surface by high frequency embossing to form an inconspicuous tear line; and

a foam layer adhered to said inner surface of said foil layer by foam backing said foil layer in a mold.

2. A cover according to claim 1, wherein said foil wall thickness is reduced by high frequency embossing a substantially inwardly V-shaped groove along said bottom channel surface.

3. A cover according to claim 1, wherein said foam layer has its foam thickness reduced in an area coinciding with the tear line.

4. A cover according to claim 3, wherein said area coinciding with the tear line is adjacent a plane of the tear line.

5. A cover according to claim 3, wherein said foam layer is reduced by forming a substantially V-shaped groove in said foam backed layer.

6. A foam-backed foil cover for an airbag unit of a motor vehicle equipped with a tear-open line, comprising:

a foil extending over an opening of the airbag unit;

said foil having an inwardly U-shaped depression;

a bottom of said U-shaped depression having a reduced thickness portion to define a tear-open line; and

a foam backing attached to the foil.

7. A cover of claim 6, wherein there is a reduced thickness in the foam backing at a point adjacent the reduced thickness portion of the foil.

8. The cover of claim 6, wherein the depression in the foil mates with a corresponding depression in the foam backing.

9. The cover of claim 7, wherein the depression in the foil mates with a corresponding depression in the foam backing.