Patent ID: 7407126
Filing Date: 2008-08-05
Classification: G11B

Abstract:
1. In combination: a recording tape cartridge and a drive device having a releasing portion, said cartridge comprising: a reel rotatably accommodated within a case, a recording tape being wound around an outer peripheral surface of a hub of the reel, which hub is shaped as a hollow cylinder having a floor wall and in whose axially central portion a pass-through hole is formed; and a braking member provided so as to be unable to rotate within the case, the braking member being able to be set at a locking position, at which the braking member engages with an engaging portion formed at a top surface of a floor portion of the floor wall of the hub and impedes rotation of the reel, and a permitting position, at which the braking member permits rotation of the reel when engagement with the engaging portion is cancelled due to the braking member moving away from the top surface of the floor portion of the hub due to pushing-up of an operation portion, of the braking member, which is inserted through the pass-through hole, said operation portion having an uppermost limit position, wherein there is formed, in said floor wall at a peripheral edge portion of the pass-through hole, a guide wall portion which extends toward the braking member and always opposes a side surface of the operation portion so that the operation portion does not come out of the guide wall portion even in said uppermost limit position and prevents tilting of the brake member, wherein an annular concave portion, having an uppermost surface, which engages with the guide wall portion in said locking position, is formed in the braking member to form a labyrinthine path which suppresses entry of dust into said case through said pass-through hole; wherein said releasing portion of said drive device, which releasing portion pushes-up the operation portion, is inserted in the pass-through hole substantially without a gap therebetween; and wherein the braking member is formed in a shape of a disc accommodated within the hub so as to be movable upward and downward, and the braking member has an integral braking gear which is provided in an annular form at an outer peripheral portion of one surface of the braking member.