Magnetic tape cassettes

Claim 1

In a magnetic tape cassette including upper and lower rectangular case members having peripheral inner walls secured together at their corners to define a hollow interior region therebetween, partition means within said interior region defining therein a recording and reproducing area and a tape storage area, a pair of parallel, rotatable reels mounted in said storage area and spaced from each other, a first pair of parallel, flanged rotary guide rollers mounted in said storage area on opposite sides of said recording and reproducing area, and a magnetic recording tape wound on and extending between said reels and guided in a path of travel through said recording and reproducing area by said guide rollers, the improvements characterized by: a. a second pair of parallel, flanged rotary guide rollers individually mounted in said storage area between said first pair of guide rollers and said reels, positioned closer to said first pair of guide rollers than to said reels, and serving to further define said path of travel of said tape, b. a plurality of elongated insert tabs mounted on and protruding along said peripheral walls, and projecting inwardly from one of said case members, and c. a plurality of elongated slots mounted on and projecting inwardly from the other of said case members, positioned to matingly receive said insert tabs when said case members are assembled and secured together, and having the bottom walls of said slots at a higher level than the height of the inner walls of said case members whereby said engaged tabs and slots increase the rigidity of said cassette and maintain the parallelism of said reels and guide rollers.