Tape recorder and magnetic tape cassette

In a magnetic tape cassette which comprises a substantially rectangular housing having a bottom wall, a top wall, a front wall and side walls and containing

• a pair of hubs each provided with a circular toothed portion and adapted to carry packs of magnetic tape, said bottom and/or top walls having therein apertures at least some of which are disposed to accommodate the drive spindles and capstans of a tape recorder, said front wall having therein at least one opening for accommodating tape-scanning means and at least one pressure roller carried by said tape recorder, said opening being arranged so that said pressure roller bears against the length of tape passing along the front wall of the cassette and on the inside thereof;
• resilient means;
• and
• control means movable against the action of said resilient means in a plane substantially parallel to the cassette plane, between a first, off-recorder position in which said control means rendor said length of tape taut along said front wall and clamp said hubs in place, and a second, on-recorder in which said control means release said length of tape as well as said hubs;
• the improvement
• that said bottom and top walls of the cassette housing are provided with cam portions;
• and
• that said control means include two slide plates each having an actuating portion engageable through one of said apertures and each having secured thereto a pawl disposed in cooperating relationship with the circular tooth portion of one of said hubs, said plates substantially overlying opposite sides of the two hubs and being yieldingly urged against the cam portions of said bottom and top walls, respectively, for longitudinal sliding movement on said cam portions, in a direction perpendicular to said front wall, between said first and second positions,
• such that said plates, as they are slidably moved by said actuating portion from their first to their second positions, impart by way of said pawls, a rocking movement to the circular toothed portions of the corresponding hubs, thereby to render said length of tape taut, and in riding up on the respective cam portions incident to their sliding movement, are displaced in a direction substantially perpendicular to the cassette plane, thereby to clamp said hubs between them.