Recording disc cartridge having an improved hub assembly

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before the description proceeds, it is noted that like parts are designated by like reference numerals throughout the attached drawings.
Referring to FIGS.
1 and 2, the disc case 1 of the recording disc cartridge is composed of the top half 1a and the bottom half 1b each made of a plastic resin, for example polystyrene resin, formed generally as a flat plate with the four peripheral sides surrounded by low vertical walls 1x.
The top half 1a and the bottom half 1b are assembled together with the corresponding bottom face of the vertical walls of the top half 1a abutted to the top face of the vertical walls of the bottom half 1b so as to provide a flat space for accommodation of the hub 8 and the recording medium 7.
The top half 1a and the bottom half 1b are securely connected by way of a supersonic welding method.
On the central portion of both the top and bottom halves 1a and 1b of the disc case 1, there are defined the drive shaft insertion holes 4.
A pair of elongated head insertion holes 5 are defined on the front portion of the top and bottom halves 1a and 1b.
A shutter mechanism (not shown) is provided in the disc case 1 so as to shut the head insertion holes 5 when the disc cartridge is not used.
When the disc cartridge is mounted on the recording/reproducing apparatus, the shutter can be moved to open the head insertion holes to allow entrance of the recording head of the recording/reproducing apparatus.
The recording disc 2 is formed by the recording medium 7 in the form of a sheet having an annular shape and the hub 8 fixed on the central part of the recording medium 7 with the top end face and the bottom end face of the hub faced to the drive shaft insertion holes 4.
The hub 8 is formed with the through hole 9 for insertion of the spindle 14 of the disc drive apparatus and with another through hole 10 defined outward of the spindle insertion hole 9 for engagement of the drive pin 15.
Cleaning liners 11 of nonwoven sheet material are laid on the inner faces of the top half 1a and the bottom half 1b so that when the recording disc is rotated upon mounting on the recording/reproducing apparatus, the surfaces of the recording medium 7 can be cleaned by sliding contact with the cleaning liners 11