Patent US4256299A successfully refreshed from Google Patents.
US4256299A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple sheet sensor and deflector
Assignee: 3M Co
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Filing: 1979-07-18
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Granted: 1981-03-17
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Expires: 1999-07-18
Abstract
Abstract A device for sensing the condition of multiple sheets during a feed of paper employing a rotatable drive roll and a rotatable backup roll eccentrically and pivotally mounted with respect to the drive roll. The device utilizes the frictional force that a sheet of paper exerts on the backup roll, as paper is driven by the drive roll through the nip which exists between the drive roll and backup roll, to pivot the backup roll around the drive roll until the backup roll reaches a position where the frictional force of the paper against the backup roll is no longer able to push the backup roll. This position is proportional to the thickness of the paper being fed. The presence of multiple sheets of paper can be detected by an ulterior position of the backup roll due to the increased thickness of the multiple sheets.
Inventors
- 👤 Raymond A. Hogenson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:38
CPC Classifications
B; B65; B65H; B65H7/00; B65H7/02; B65H7/06; B65H7/12
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
211 words
In combination with a sheet feeder, an apparatus for sensing the thickness of the sheet being fed comprising a frame, a drive roll for driving sheet material, means mounting said drive roll for rotation about a fixed axis in said frame, drive means for said drive roll, a cooperating back-up member positioned parallel and adjacent to said drive roll so as to form an elongate nip area therebetween, means mounting said back-up member, on a pivot axis offset from said fixed axis of said drive roll to afford the limited angular rotation of said back-up member about said pivot axis and the partial revolution of said back-up member around said drive roll, thereby increasing the nip spacing between said drive roll and said back-up member, said back-up member having a home position at which said nip area has a predetermined spacing and ulterior positions at which the spacing of said nip area is responsive to the thickness of the sheets being driven between said drive roll and said back-up member, whereby multiple sheets will interpose said nip area, and following the rotation of the drive roll, push said backup member about said pivot axis to one of said ulterior positions, and means for biasing said back-up member to said home position.
Claim 2
Dependent Claim
211 words
In combination with a sheet feeder, an apparatus for sensing the thickness of the sheet being fed comprising a frame, a drive roll for driving sheet material, means mounting said drive roll for rotation about a fixed axis in said frame, drive means for said drive roll, a cooperating back-up member positioned parallel and adjacent to said drive roll so as to form an elongate nip area therebetween, means mounting said back-up member, on a pivot axis offset from said fixed axis of said drive roll to afford the limited angular rotation of said back-up member about said pivot axis and the partial revolution of said back-up member around said drive roll, thereby increasing the nip spacing between said drive roll and said back-up member, said back-up member having a home position at which said nip area has a predetermined spacing and ulterior positions at which the spacing of said nip area is responsive to the thickness of the sheets being driven between said drive roll and said back-up member, whereby multiple sheets will interpose said nip area, and following the rotation of the drive roll, push said backup member about said pivot axis to one of said ulterior positions, and means for biasing said back-up member to said home position.
Claim 3
Dependent Claim
32 words
An apparatus as recited in claim 1 including deflection means cooperating with said back-up member such that the feeding of multiple sheets will cause said deflection means to deflect said multiple sheets.
Claim 4
Dependent Claim
26 words
An apparatus as recited in claim 1 wherein said back-up member is a roll mounted for rotation about an axis fixed within said pivotal mounting means.
References Cited (Backward Citations)
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US2670954A
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US2890884A
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US3202421A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |