Patent US3883998A successfully refreshed from Google Patents.
US3883998A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fastening device for psa abrasive disc
Assignee: 3M Co
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Filing: 1974-02-11
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Granted: 1975-05-20
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Expires: 1994-02-11
Abstract
Abstract A backup pad having a protruding centering button to quickly fasten pressure sensitive adhesive abrasive discs and other surface treating discs on a backup pad for a conventional power rotary tool.
Inventors
- 👤 Dale M Dosser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:42
CPC Classifications
B; B24; B24D; B24D9/00; B24D9/08; B24D9/085
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
155 words
In combination, a rotary backup pad and a pressure sensitive adhesive abrasive disc having a centering opening of a regular geometric shape, said backup pad designed for supporting and readily removably retaining said disc, said backup pad comprising a circular backup plate having a disc supporting surface; a central fitting adapted to connect to a rotary driving shaft of a power driven tool; a centering button which protrudes from the disc supporting surface, which button is formed at its protruding end with a shoulder which is slightly larger than the opening of the disc and with a neck which is equal to or slightly smaller than the opening of the disc and has a length equal to or greater than the thickness of the disc at its opening to center the abrasive disc on the support surface and to restrict lateral displacement of the abrasive disc relative to the backup pad during the operation thereof.
Claim 2
Dependent Claim
155 words
In combination, a rotary backup pad and a pressure sensitive adhesive abrasive disc having a centering opening of a regular geometric shape, said backup pad designed for supporting and readily removably retaining said disc, said backup pad comprising a circular backup plate having a disc supporting surface; a central fitting adapted to connect to a rotary driving shaft of a power driven tool; a centering button which protrudes from the disc supporting surface, which button is formed at its protruding end with a shoulder which is slightly larger than the opening of the disc and with a neck which is equal to or slightly smaller than the opening of the disc and has a length equal to or greater than the thickness of the disc at its opening to center the abrasive disc on the support surface and to restrict lateral displacement of the abrasive disc relative to the backup pad during the operation thereof.
Claim 3
Dependent Claim
33 words
A combination of claim 1 wherein said central fitting is integral with said centering button and has an inner threaded bore portion that screws onto the driving shaft of the rotary power tool.
Claim 4
Dependent Claim
25 words
A combination of claim 1 wherein the circular backup plate, the central fitting and the centering button are formed as a single piece of material.
Claim 5
Dependent Claim
35 words
A combination of claim 1 wherein the disc supporting surface of the backup plate is covered with a resilient surfacing adapted to aid in receiving and holding the pressure sensitive adhesive coated abrasive disc thereon.
Claim 6
Dependent Claim
42 words
A combination of claim 1 wherein the shoulder of said centering button has an under surface spaced from and opposed to said supporting surface to engage the abrasive surface of a said abrasive disc adjacent to the opening in the abrasive disc.
Claim 7
Dependent Claim
32 words
A combination of claim 1 wherein a centering button is located at the center of the backup pad and is internally threaded to provide at least a part of the central fitting.
Claim 8
Dependent Claim
17 words
A combination of claim 1 wherein the centering button is an integral part of the backup plate.
Claim 9
Dependent Claim
56 words
The combination of claim 1 wherein the central fitting is provided by an internally threaded metal hub permanently affixed to the backup plate, and the centering button is a separate metal piece which is internally threaded for attachment to the driving shaft of the power tool, and the backup plate is depressed around the central fitting.
Claim 10
Dependent Claim
38 words
The combination of claim 7 wherein the centering button, when the backup pad and abrasive disc are attached to the power tool, does not substantially project beyond the plane of the outer working portion of the abrasive surface.
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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |