Patent ID: 6736344
Filing Date: 2004-05-18
Classification: G11B

Abstract:
A magnetic tape cartridge comprising:a cartridge case where a single reel with magnetic tape wound thereon is rotatably housed; and reel-rotation restraining means which, when the cartridge case is not being used, goes to a locked state to restrict rotation of said reel and, when the cartridge case is being used, goes from said locked state to an unlocked state to allow said rotation; said reel-rotation restraining means having a restraining member for restricting rotation of said reel by moving toward or away from said reel, an urging member for urging said restraining member in a restraining direction, and an unlocking member for moving said restraining member in an unlocking direction by rotating integrally with said reel and moving according to a chucking operation of rotation means of a drive unit; wherein said reel has a reel gear which meshes with a driving gear of drive means of said drive unit; said unlocking member has a main body which abuts said restraining member, and leg portions whose lower ends abut part of said drive means of said drive unit through guide holes provided to penetrate said reel gear; and in said locked state, the lower ends of said leg portions of said unlocking member project from a tooth edge of said reel gear.