Patent ID: 7128288
Filing Date: 2006-10-31
Classification: G11B

Abstract:
1. A magnetic tape cartridge comprising: a case including a rib projecting therefrom, the rib including a datum hole passing therethrough into which a positioning pin is inserted at a predetermined position thereof; a reel rotatably supported on the case with a magnetic tape wound thereon and including an engaging gear formed in the outer periphery of a flange thereof; a rotation restricting mechanism disposed in the case and engaging with the engaging gear of the reel to thereby restrict the rotation of the reel; and, an engagement releasing element slidably inserted into the datum hole from inside the case and removing the engagement between the rotation restricting mechanism and the engaging gear through the sliding movement thereof within the datum hole, wherein an inner peripheral surface of the datum hole has a groove, an outer peripheral surface of the engagement releasing element has a projection so as to slidably engage with the groove, and the positioning pin is inserted into the datum hole from outside of the case and pushes and slides the engagement releasing element, thereby releasing the rotation restriction of the reel by the rotation restricting mechanism.