Magnet ring configuration and disc cartridge including magnet ring configuration
AssigneeNashua Corporation
InventorGeorge T. Cheney
Life of this patent
Estimating the term…
Abstract
The tendency of circular draw plates used in disc cartridges containing a magnetic disc memory to warp during fabrication is significantly reduced by a draw plate which includes two warp reducing apertures each spaced at an angle of 90.degree. from the posts along the circumference of said draw plate. An improved post is disclosed. The post includes a coarse knurl which is urged into a post aperture formed in the draw plate. A ring magnet in the bottom cover is also disclosed. The single ring magnet replaces several pot magnets of prior art cartridges and significantly reduces the cost of producing the disc cartridge. A U-shaped magnet cup into which a magnet is positioned concentrates the magnetic lines of force and thereby increases the magnet's magnetic efficiency.
Claims5
A disc cartridge of the type which includes a memory disc covered by two covers, a top and a bottom cover, and a draw plate of a type which has post apertures through which posts are secured to the draw plate and a pair of posts for engagement with a handle assembly on one cover and which draws the memory disc toward one cover when the handle is rotated, wherein the improvement comprises said draw plate having a pair of warp reducing apertures, each of said warp reducing apertures and the post apertures being located an equal distance from the center of the circular draw plate and each warp reducing aperture being along an inner circumference of said circular draw plate at a distance of 90.degree. of arc from a post aperture also located along said inner circumference, the bottom of the posts having a coarse knurl formed thereon which friction fits directly into a post aperture formed in the material from which the draw plate is fabricated, the direct fitting of said posts into the draw plate enabling the posts to be flexed to facilitate the alignment of the posts with the handle assembly and wherein the bottom cover of the cartridge includes a ring magnet positioned on the inside thereof, said ring magnet making magnetic contact with an armature plate which is connected to said top cover to maintain said cartridge in a closed position.
A disc cartridge of the type which includes a memory disc covered by two covers, a top and a bottom cover, and a draw plate of a type which has post apertures through which posts are secured to the draw plate and a pair of posts for engagement with a handle assembly on one cover and which draws the memory disc toward one cover when the handle is rotated, wherein the improvement comprises said draw plate having a pair of warp reducing apertures, each of said warp reducing apertures and the post apertures being located an equal distance from the center of the circular draw plate and each warp reducing aperture being along an inner circumference of said circular draw plate at a distance of 90.degree. of arc from a post aperture also located along said inner circumference, said bottom cover of the cartridge including a ring magnet positioned on the inside thereof, said ring magnet making magnetic contact with an armature plate which is connected to said top cover to maintain said cartridge in a closed position, said ring magnet being positioned within a magnet cup formed of a ferrous material which is generally U-shaped in cross-section, said magnet cup forming two circular legs which form opposite poles for said ring magnet and which contact the armature plate to maintain the disc cartridge closed when desired.
Dependencies are inferred from the claim text.