| 摘要 |
PROBLEM TO BE SOLVED: To combine halves of which a disc cartridge consists with each other firmly. SOLUTION: A cartridge case in which a record medium 3 is rotatably housed is composed of a pair of facing upper and lower case halves 1 and 2 which are made of hard synthetic resin and welded to each other by ultrasonic welding. The halves 1 and 2 respectively have plate parts 1a and 2a and boss-shape linkage standing parts 4 and 5 protruding from both the facing surfaces of the plate parts 1a and 2a. The standing part 4 has recessed hole 6 which is recessed from its top surface and a stepped part 7 is formed on the inner circumferential edge of the entrance part of the recessed hole 6. Ribs 8 for ultrasonic welding are provided on the bottom surface 7a of the stepped part 7 and slender ribs 10 are formed on the circumferential wall 7b. The crossing angle (a) of the bottom surface 7a and circumferential wall 7b of the stepped part 7 is larger than the crossing angle (b) of the top surface and outer circumferential surface of the standing part 5.
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