Each of the Betamax and VHS videotape cassettes has a pair of plastic brake levers which engage peripheral teeth in the lower flange of each tape reel to lock the reels when the cassette is not in use. The braking mechanism of a conventional Betamax videotape cassette is illustrated in FIGS. 1-5 of U.S. Pat. No. 4,214,719 (Kato). As disclosed at the bottom of column 4, when the visor-type door or lid 5 is opened, actuating projections 6'rotate or pivot brake levers 33a and 33b against urging forces of respective torsion springs to disengage a finger 36 of each lever from the teeth 26 of the reels (see also FIG. 11).
The braking mechanism of a conventional VHS videotape cassette is illustrated in U.S. Pat. No. 4,106,724 (Higashida). When a VHS videotape cassette is positioned on a deck, a fixed pin 26 on the deck rotates or pivots a brake release member 21, which in turn pivots the pair of brake levers 15 and 16 against the force of springs 19 and 20 to lift the fingers 15a and 16a out of engagement with the teeth 12 and 11, respectively.
The brake levers limit the amount of tape that can be wound into the Betamax and VHS videotape cassettes and hence limit the playing time.
The takeup reel of the VHS-C (compact) videotape cassette has peripheral teeth in its lower flange, by which the reel is locked when the cassette is not in use. The outer face of the supply reel is formed with teeth which fit into indentation formed in the base of the cassette and are pressed against those indentations by a metal leaf spring which is mounted on the cover of the cassette and presses against the hub of the supply reel. In spite of this, the supply roll sometimes rotates when handled and shipped so that the tape becomes loose and tangled.
USPTO Backgrounds
USPTO Backgrounds