Magnetic recording disc cartridge

Claim 1

A magnetic recording disc cartridge which comprises; a cartridge case composed of a pair of plate members placed opposite to each other with a predetermined space therebetween, one of said plate members having a first opening for receiving a drive shaft of a recording/reproducing apparatus and a second opening for receiving a magnetic recording head of said recording/reproducing apparatus; a magnetic recording disc formed by a magnetic recording sheet having a central hole defined in a central portion thereof; and a hub assembly mounted in said central hole of said magnetic recording sheet and having a central hole for receiving a drive shaft of said recording/reproducing apparatus, said magnetic recording disc being rotatably contained in said predetermined spaced between said pair of plate members of said cartirdge case in such a manner that said central hole of said hub assembly is opposed to said first opening, said hub assembly being composed of an upper hub member and a lower hub member respectively positioned on opposite sides of the disk, each said hub members comprising corresponding, radial, inner and outer portions inseparably connected with each other, said inner portions engaging a portion of said recording sheet peripherally surrounding said central hole between respective surfaces of said inner portions of said hub members, said outer portions of said upper and lower hub members having respective opposed surfaces adjacent the recording sheet which are spaced apart a greater distance than the thickness of said recording sheet thereby forming clearances between respective surfaces of said magnetic recording disc and said opposed surfaces of said hub-outer portions of said hub members.