Abstract: An optical recording disc in which a disc substrate made of a synthetic resin having a light transmittance and a hub made of a synthetic resin, fixed to a center part of the disc substrate by means of a predetermined technique such as a supersonic wave expansion molding and on which a circular magnetic metal plate is installed by means of an insert molding and so on are provided and a circular groove which is continuous at an outer peripheral side of a fixing part between the disc substrate and hub is furthermore installed on at least either of the disc substrate or hub. The groove is provided for absorbing a stress generated due to a difference in thermal expansion rates between the disc substrate made of the snythetic resin and magnetic metal plate.

Abstract: A magnetic recording disk cartridge comprises a magnetic recording disk accomodated for rotation in a casing. The magnetic recording disk is provided with a center core having a central opening into which a spindle of a magnetic recording/reproducing system is inserted to be drivingly engaged therewith. The center core comprises a core block provided with the central opening and a pair of slits formed in the wall portion of the core block defining the central opening and spaced from each other by a predetermined distance; and a plate spring which extends across the central opening and the opposite end portions of which are fitted into the slits and held therein so that the plate spring can be resiliently deformed in a direction radial to the magnetic recording disk.

Abstract: Disclosed herein is a recording disc cartridge having recording disc rotatably mounted in a cartridge case by a hub assembly. The hub assembly comprises a receiving hole defined in its central portion for receiving a supporting shaft of a drive unit of a recording/reproducing apparatus, at least two wall members having flat surfaces disposed to face to the central hole with a predetermined angle in plan view, an annular guide groove formed around the receiving hole to receive a drive shaft of the drive unit and a rib member formed across the guide groove for being engaged with the drive shaft in such a position that the supporting shaft is pressed against the two flat wall members by rotational force of the drive shaft. A resilient arcuate arm projects from one of the wall members to clamp the supporting shaft of the drive unit of the recording/reproducing apparatus in the receiving hole of the hub assembly.

Abstract: A disk drive system according to the present invention comprises a spindle in a drive unit. The spindle is formed, at its free end, so that it has a flat portion. A magnetic disk which is adapted to be rotated by the spindle is provided having a center hub in its central portion. An opening in the shape of a right-angled isosceles triangle is formed in the center of the center hub. The free end of the spindle can be inserted into the opening, with some play therebetween, only when it is located within a predetermined range of the phase angle of rotation relative to the magnetic disk. The opening has, on its base, a first contact point adapted to abut against one side edge of the flat portion, located on the front side, when the free end of the spindle is inserted into the opening. The opening also has, on the two remaining sides thereof, second and third contact points adapted to engage some other portions of the outer peripheral surface of the free end of the spindle.

Abstract: An optical recording disc comprises a first bonding recess formed near an outside surface of an optical recording disc in a bonding boundary portion between a cylindrical hub and a transparent disc substrate, a disc member bonded with said transparent disc substrate through said cylindrical hub, and a second bonding recess formed near the outside surface of said optical recording disc in a bonding boundary portion between said cylindrical hub and said disc member. Accordingly, said optical recording disc can prevent remainder of a bonding material for bonding a pair of said transparent disc substrates or said transparent disc substrate and said disc member together from pushing out of the outside surface of the optical recording disc, resulting in that focusing for reading and writing an information signal can be properly performed.

Abstract: In a rotary drive apparatus for a disk of the type in which the disk is mounted on a turntable, a central pin arranged at the center of the turntable and a drive pin arranged in a position spaced radially from this center of the turntable are respectively inserted in a central hole of the disk and a drive hole spaced radially from the central hole of the disk so that the disk is driven by the drive pin upon rotation of the turntable, and the drive hole of the disk is urged radially away from the center of the turntable by the drive pin so that the periphery of the central pin is pushed against the edge of the central hole for making the center of the disk coincide with that of the turntable; the drive pin is mounted for movement in a direction opposite to the rotating direction of the turntable and simultaneously in a direction radially away from the center of the turntable in reaction to the driving of the disk by the drive pin, thereby to ensure that the force that moves the drive hole of the disk in the di

Abstract: A magnetic disk cartridge containing a floppy magnetic disk is provided with center core which has a groove where the vertical part of the core meets the flange upon which the disk is fastened by a double-sided adhesive ring. This groove can accommodate a portion of the adhesive ring which is positioned out of true. This ensures that such misalignment does not cause deformation of the disk and the deterioration in read/write performance with the disk. The groove also serves to prevent flange flashing from scraping fragments off the inside of the cartridge wall, and the possible harm such fragments cause if they stick to the disk.

Abstract: Concentric guide grooves are formed on a glass substrate, and recording medium is disposed on the glass substrate having the concentric grooves. A centering device is secured to the glass substrate in a manner that the center of the centering device is positioned at the center of the concentric guide grooves. In a preferred form, photopolymer is disposed between the centering device and the glass substrate as adhesive. The centering device is provided with an aperture through which ultraviolet rays are applyed to the photo-polymer to cure it.

Abstract: In a flexible magnetic disc adapted for mounting on a drive spindle of a recording and/or reproducing apparatus and having a hub structure secured to a flexible magnetic sheet member at the center of the latter and defining a bore for receiving the drive spindle; the hub structure includes a substantially circular metal plate with a central aperture substantially registering with the bore and which, at its edge, defines a pair of positioning surfaces projecting into the bore at locations spaced apart about its axis, and a metal spring also projecting into the bore at a side of the latter remote from the positioning surfaces and located by positioning seats also defined at the edge of the aperture in the circular metal plate for engaging the metal spring with the drive spindle in the bore and securely seating the drive spindle against the metal positioning surfaces.

Abstract: An information record disc for use in a magnetic recording and reproducing apparatus to provide a plurality of still pictures in a plurality of spiral tracks on a magnetic disc thereof, includes an annular magnetic plate having an aperture therein; and a cylindrical central core made of plastic and formed with the magnetic plate by an outsert molding process in which the central core includes an upper section extending above the magnetic plate, a lower section extending below the magnetic plate and a connecting section connecting the upper and lower sections through the aperture, the upper and lower sections being offset from the aperture, so that an integral structure is provided with the central core and the magnetic plate, and with the magnetic plate thereby having an outwardly extending radial flange which extends radially outward from the central core and to which the magnetic disc is secured and an inwardly extending radial section which extends inwardly of the central core and which is attracted by a m

Abstract: An improved reinforcement member for a central aperture in a flexible recording disk and a method for forming the same. The improved reinforcement comprises an integral, annular-shaped ring formed on one or both sides of the flexible recording disk about the central aperture thereof. This improved reinforcement is formed by transfer printing a liquid image of the reinforcement member onto a side surface of the flexible recording disk and then subsequently solidifying that liquid image. The liquid image to be transfer printed onto the flexible recording disk is first established by filling a metering reservoir shaped to be an image of the reinforcement member with a solidifying liquid. A terminal end of compliant rubber tampon is then first contacted to the reservoir thereby picking up the liquid image which is then contacted to the surface of the flexible disk to be deposited there.

Abstract: A magnetic disk assembly is comprised of a magnetic disk and a hub member centrally positioned on that disk and having a non-circular opening for receiving a circular drive shaft which serves to rotatably drive the magnetic disk. The hub member includes at least two reference surfaces which converge toward each other and which form two respective walls of the opening, and one or more resilient members having a surface which forms a third wall of the opening. The three walls are positioned and dimensioned such that when a circular drive shaft is received, the reference surfaces and the surface of the resilient member all tangentially contact the drive shaft to be rotated thereby when the drive shaft rotates.

Abstract: A record (12) comprising a convex protrusion (12a) at its center, one or more protrusions (12b) extending perpendicularly from the plane of the record at its circumferential edge, and a recording area between the center and the circumferential edge. The protrusions engage similar indentations (3b, 3e) formed in a turntable to facilitate centering and holding the record for playing and to prevent rotational slippage.

Abstract: A disc is provided which centers itself on motor shafts that vary somewhat in diameter. The disc is formed of a single sheet of material with a central hole for receiving the shaft and with a group of fingers projecting slightly into the hole to engage a shaft. The fingers are formed by pairs of slots that extend from the edge of the central hole and radially outward to form fingers of considerable length which can be bent out of the plane of the disc to engage shafts of varying size. The radially inner tips of the fingers lie precisely on an imaginary circle which is slightly smaller than the minimum diameter of a shaft, and the fingers deflect uniformly to hold the shaft centered on the axis of the disc.

Abstract: A hub and spindle assembly for an interchangeable, removable disk of a disk drive. The spindle assembly includes means for driving the hub assembly, matingly attached and removably engaged thereto, so as to rotate the disk coupled to the hub. The hub assembly includes surfaces for engaging an accurately machined rotational surface of the spindle assembly and force engaging means for ensuring mating contact of the hub assembly surfaces with the spindle assembly and for ensuring removeable engagement. The hub and spindle assembly minimize runout such that the Read/Write heads track an essentially circular disk track, even if the disk is removed, reinserted or placed on a different spindle of the same type.

Abstract: A playback instrument for a record disc, the instrument including a turntable for supporting the disc to be played on which the disc is centered by means of a central bore, is provided with two annular, concentrically disposed, radially spaced flat bearing surfaces mounted on the turntable for the disc, the surfaces forming a rigid support, one bearing surface being disposed in the vicinity of the location of the center of such disc and the other bearing surface being disposed radially to the outside of the one surface at a distance from the location of the center of such disc, and disc holding components provided for exerting on such disc an attracting force of such magnitude as to cause the disc to contact the bearing surfaces over the entire area thereof.

Abstract: Microphonograph record which is to remain stationary while information is being reproduced therefrom formed from a sheet of material and having generally V-shaped locating means formed in the sheet of material which is accessible from one side of the sheet of material. The V-shaped locating means lies in a plane generally parallel to the plane of the sheet of material. The sheet of material is provided with first and second surfaces and has information carried by the sheet of material on at least one surface thereof and arranged in a generally concentric circular pattern. The circular pattern has at its center a point which lies in close proximity to the apex of the V-shaped locating means.