Patent ID: 7540446

Claim:
A recording tape cartridge comprising: a reel having a cylindrical hub with a bottom and a reel gear formed therein with recording tape wound around the outer peripheral surface of the hub; a casing in which the reel is singly and rotatably accommodated; a brake component that is provided inside the hub and made to be non-rotatable relative to the casing and which, when not in use, engages an engaging portion formed in the hub and blocks rotation of the reel; and a releasing component that is provided between the bottom of the hub and the brake component and which has a plurality of legs inserted through a plurality of through-holes formed on the reel gear where, when in use, the plurality of legs are pressed upwards by a drive gear of a drive device, whereby the releasing component lifts the brake component, releases engagement with the engaging portion and rotates with the reel, wherein the plurality of legs are formed into approximate D shapes in plan view whose outer side surfaces facing an inner peripheral surface of the hub are flat surfaces, while the plurality of through-holes are formed into approximate D shapes in plan view whose outer peripheral portions facing an inner peripheral surface of the hub are approximate straight-line through which the plurality of legs can each be inserted.