US4013169A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnet ring configuration and disc cartridge including magnet ring configuration
Assignee: Nashua Corp
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Filing: 1975-12-05
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Granted: 1977-03-22
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Expires: 1995-12-05
Abstract
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° 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.
Inventors
- 👤 George T. Cheney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:28
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/02; G11B23/03; G11B23/032; G11B23/0321; G11B23/0322; G11B17/00; G11B17/32; Y; Y10; Y10S; Y10S206/00; Y10S206/818
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
237 words
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° 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.
Claim 2
Dependent Claim
237 words
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° 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.
Claim 3
Dependent Claim
58 words
The disc cartridge as set forth in claim 1 wherein said ring magnet is 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 contact said armature plate to maintain the disc cartridge closed when desired.
Claim 4
Dependent Claim
23 words
The disc cartridge as set forth in claim 2 wherein said magnet cup is formed of a stainless steel from the 400 series.
Claim 5
Dependent Claim
227 words
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° 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.
Claim 6
Dependent Claim
227 words
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° 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.
Claim 7
Dependent Claim
23 words
The disc cartridge as set forth in claim 4 wherein said magnet cup is formed of a stainless steel from the 400 series.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |