Hub for use in a magnetic recording tape cassette

Claim 1

A hub for use in a magnetic recording tape cassette which comprises an annular body having a cylindrical outer peripheral surface on which a magnetic recording tape is wound, an engagement recess defined in the outer peripheral portion of the annular body and a clamp piece fitted in the engagement recess, wherein said engagement recess comprising an entrance opening formed in the cylindrical outer peripheral surface of the annular body, a pair of protrusions protruded inwardly of the recess to define a first space narrower than the width of the entrance opening on the intermediate portion of the both lower side walls of the engagement recess and an inner recess defined by a bottom face of the engagement recess and the both side walls thereof with a second space wider than the first space, said clamp piece comprising a top portion having an arcuated surface with the substantially same curvature as the cylindrical outer surface of the annular body and with such a length in a circumferential direction that the top portion closes the entrance opening, a bottom portion having a pair of lugs protruding substantially towards the top portion from the both sides of said bottom portion with such a length that, when the clamp piece is fitted in the engagement recess, the lugs are engaged with the lower side walls of the recess and an intermediate portion for connecting the top portion and the bottom portion, whereby when said clamp piece is fitted in the engagement recess with the magnetic tape inserted therebetween, the magnetic tape is secured on the hub in such manner that the magnetic tape is clamped between the ends of the lugs and at least one of the side walls of the engagement recess.