Patent US1798280A successfully refreshed from Google Patents.
Patent US4147524A successfully refreshed from Google Patents.
US4147524A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter unit
Assignee: Donaldson Co Inc
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Filing: 1978-04-24
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Granted: 1979-04-03
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Expires: 1998-04-24
Abstract
Abstract A plurality of laterally spaced parallel tapes extend along each side of a strip of filter material in engagement with it, and the sheets and tapes are in accordion folded form so that there is a stack of integrally connected parallel filter sheets spaced apart by the portions of the tapes between them. Each tape has at its side of the stack exposed portions, along which a line of hardened adhesive extends to connect them and form a stiffening band, whereby there are parallel stiffening bands extending across each side of the stack of filter sheets.
Inventors
- 👤 Wayne L. Smith
- 👤 Roger P. Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:50
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/52; B01D46/521; B01D46/523; B01D46/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
103 words
A filter unit comprising a strip of filter material, a plurality of laterally spaced parallel tapes extending along each side of the strip in engagement therewith, the strip and tapes being accordion-folded transversely thereof and forming a stack of integrally connected parallel filter sheets spaced apart by the portions of the tapes between them, each tape having at its side of the stack exposed portions, and a line of hardened adhesive extending along said exposed portions of each tape to connect them and form a stiffening band, whereby there are parallel stiffening bands extending across each side of said stack of filter sheets.
Claim 2
Dependent Claim
103 words
A filter unit comprising a strip of filter material, a plurality of laterally spaced parallel tapes extending along each side of the strip in engagement therewith, the strip and tapes being accordion-folded transversely thereof and forming a stack of integrally connected parallel filter sheets spaced apart by the portions of the tapes between them, each tape having at its side of the stack exposed portions, and a line of hardened adhesive extending along said exposed portions of each tape to connect them and form a stiffening band, whereby there are parallel stiffening bands extending across each side of said stack of filter sheets.
Claim 3
Dependent Claim
32 words
A filter unit according to claim 1, including a plurality of laterally spaced rigid bars extending along some of said stiffening bands at only one side of said stack and adhering thereto.
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) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |