US Patent 7533840 Reel and recording tape cartridge

A reel that includes: an upper flange and a lower flange that retain width direction edge portions of a recording tape; a lower circular cylinder portion disposed extending upward from an upper surface of the lower flange on the same circumference as the axial center of the lower flange; a hub that is fitted over the outside of the lower circular cylinder portion and around which the recording tape is wound; a rotational detent member that regulates movement of the hub in the circumferential direction with respect to the lower flange; and an upper circular cylinder portion that extends downward from an undersurface of the upper flange and is welded to an end surface of the lower circular cylinder portion such that the hub is interposed and held between the upper flange and the lower flange. A recording tape cartridge that includes this reel.