US005839752A [ii] Patent Number: 5,839,752  Date of Patent: Nov. 24, 1998
 References Cited
U.S. PATENT DOCUMENTS
5,180,187 1/1993 Muller et al 280/732
5,698,283 12/1997 Yamasaki et al 280/728.3
FOREIGN PATENT DOCUMENTS 51-1932 8/1976 Japan .
4151345 5/1992 Japan 280/728.3
Primary Examiner—Christopher P. Ellis
Attorney, Agent, or Firm—Cushman Darby & Cushman, IP
Group ol Pillsbury Madison & Sutro LLP
An air bag cover is made ol thermoplastic resin and covers an air bag. A plurality ol holes are provided with the air bag cover continuously and a breakable portion is provided which severs upon the inflation ol the air bag. The surface side ol the breakable portion is processed by a heating process, so that protrusions which partially plug the holes are formed on the inner circumlerential surface ol the holes on the surface side.
16 Claims, 6 Drawing Sheets