| 摘要 |
A pair of upper and lower cassette halves (2), (3) constituting a cassette case (1) are each provided with a window member (5) for viewing the state of winding of a magnetic tape accommodated in the case and a cassette half body (4) for supporting the window member (5). The upper and lower cassette halves (2), (3) are welded and joined by a plurality of welding ribs (23), (24) provided projectingly on joining faces of mutually opposing cassette-half peripheral side walls (8) of the cassette half (4). Further, each of the welding ribs (24) adjacent to a narrow portion (K, L) of the cassette-half body (4) where an interval between a peripheral edge of the window member (5) and the peripheral side wall (8) is narrow as compared with a remaining portion of the cassette-half body portion is provided in such a manner as to extend without a joint along at least an area of the narrow portion (K, L). Accordingly, an inexpensive magnetic tape cassette is provided in which a pair of upper and lower cassette halves each comprised of a window portion and a cassette-half body portion for supporting the window portion are welded to each other by ultrasonic welding, and which has high strength and is free from the occurrence of a gap between joined faces. <IMAGE> |
