Patent ID: 7237740

Claim:
A recording tape cartridge comprising: an engagement portion which is formed on a bottom wall of a hub of a reel which is rotatably accommodated in a case and on which a recording tape is wound; a brake member facing the engagement portion and provided so as to be movable along an axial direction of the hub, the brake member engaging with the engagement portion to regulate rotation of the reel and releasing the state of engagement with the engagement portion to allow rotation of the reel; a component mounting portion which is formed at the central portion of the case and positioned further at the inner side of the hub in a radial direction of the reel; a lock member, mounted at the component mounting portion so as to be movable in the radial direction of the reel and provided between the reel and the case to regulate at least movement of the reel in the axial direction, which moves away from the reel by being pressed by the brake member to thereby allow movement of the reel, the lock member having a center of gravity thereof provided along a direction in which the brake member initially comes into contact with and presses the lock member; and a biasing member which biases the lock member in the radial direction of the reel.