This invention relates to a tape cassette having a case which is smaller, especially in thickness, than a conventional tape cassette and which can still accommodate a magnetic tape of the same width as can a conventional tape cassette, and to an adaptor for mounting such a tape cassette to a conventional tape recorder.
Among cassette tapes, the most widespread now in use are called compact cassettes, which contain a magnetic tape having a width of 3.8 mm and have a standardized shape and size, i.e. a length of 100 mm, a width of 64 mm and a thickness of 8.5 mm (FIG. 8).
A handy tape recorder for this type of compact cassette is rather small and lightweight. In fact, the latest model is only slightly larger than the cassette itself. In other words, further reduction in size of the hardware part of the tape recorder is almost impossible.
On the other hand, a micro-cassette is known which is extremely small (50 mm in length, 33 mm in width and 8 mm in thickness). But since its sound information recording capacity is smaller than a compact cassette and it cannot feed the tape stably due to its fragile build, its sound quality is considerably poor. Thus, tape recorders for micro-cassettes are not popular in spite of their compact size.
For the above reasons, it is essential, in attempting to realize a reduction in size of a tape cassette, not to impair the sound information recording capacity, not to impair the sound quality and to keep a sufficient strength of the cassette itself.
Also, it is desirable that such a small and thin tape cassette be capable of being recorded with and being replayed on a conventional compact cassette tape recorder.
Japanese Unexamined Patent Publication No. 56-98757 discloses a compact cassette in which a tape cassette is inserted in a case to protect its magnetic tape during transportation and which can be mounted on a tape recorder with the tape cassette received in the case.
Also, Japanese Examined Patent Publication No. 57-58752 discloses a solid type tape cassette having a solid interior except at some portions. It has an increased strength.