Magnetic tape cassette

Claim 1

A magnetic tape cassette comprising: a cassette case having upper and lower halves; first and second magnetic tape winding hubs arranged in respective right and left positions in an interior of said cassette defined by said upper and lower halves of said case, each of said two hubs comprising a first cylindrical wall forming a shaft hole adapted to receive a rotary drive shaft, and a second cylindrical wall formed coaxially with said first cylindrical wall, said second cylindrical wall having a plurality of engaging grooves formed in an inner surface thereof; locking means comprising a crosswise locking member slidably supported on a bottom of said lower half between said hubs, said locking member comprising a straight bar and oppositely extendable arms substantially in the form of a cross with an upstanding pawl on the outer end of each arm disposed intermediate said first and second cylindrical walls and a spring member, said locking member being moveable back and forth in the longitudinal direction of said straight bar and being urged in one direction by said spring member to bias said pawls into engagement with said grooves, rotation in at least one direction of said hubs being stopped by engagement of said locking pawls with said engaging grooves; a magnetic tape laid over said hubs; and a tape running guiding means arranged symmetrically right and left in said case so as to guide said tape across an opening in said case in a front portion thereof.