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US4034765A Expired / Lapsed US ⏱️ 0.0 years remaining

Tobacco smoke filter

Assignee: Liggett Group LLC
•
Filing: 1975-10-30
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Granted: 1977-07-12
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Expires: 1995-10-30
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Abstract

Abstract This invention relates to a cigarette filter composed of two concentric cylindrical layers of fibrous filter materials, in which the inner cylindrical layer has a lower draw resistance than the outer cylindrical layer.

Inventors

  • 👤 Floyd Van Hall

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 09:16
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/02; Y; Y10; Y10S; Y10S493/00; Y10S493/941

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 234 words
A tobacco filter cigarette comprising a tobacco column, a filter mouthpiece and a cylinder of tipping paper joining said filter mouthpiece to said tobacco column, said filter mouthpiece consisting of a first cylindrical passageway comprised of a coarse cellulose acetate fibrous tow having a dpf value from about 7 to about 9 and a total denier value from about 15,000 to about 25,000, said first passageway having a cross-sectional area that is no more than 25 percent of the total cross-sectional area of said filter, a second passageway comprised of a compacted cellulose acetate fibrous tow having a dpf value from about 1 to about 5 and a total denier value of from about 10,000 to about 50,000, said second passageway circumferentially enveloping said first passageway, and said dpf value for the tow of said first passageway being from about 1.5 to 5 times the dpf value for the tow of said second passageway, and a cylinder of air pervious plugwrap paper receiving and defining said second passageway, said tipping paper having a plurality of perforations communicating the surrounding air with said second passageway defining an air flow path having a draw resistance to complement said draw resistance of said first passageway whereby for a givendraw ventilation air, in an amount of from about 15 percent to about 60 percent of the total delivered puff volume, and relatively unfiltered smoke eneters the smoker's mouth.
Claim 2
Dependent Claim 234 words
A tobacco filter cigarette comprising a tobacco column, a filter mouthpiece and a cylinder of tipping paper joining said filter mouthpiece to said tobacco column, said filter mouthpiece consisting of a first cylindrical passageway comprised of a coarse cellulose acetate fibrous tow having a dpf value from about 7 to about 9 and a total denier value from about 15,000 to about 25,000, said first passageway having a cross-sectional area that is no more than 25 percent of the total cross-sectional area of said filter, a second passageway comprised of a compacted cellulose acetate fibrous tow having a dpf value from about 1 to about 5 and a total denier value of from about 10,000 to about 50,000, said second passageway circumferentially enveloping said first passageway, and said dpf value for the tow of said first passageway being from about 1.5 to 5 times the dpf value for the tow of said second passageway, and a cylinder of air pervious plugwrap paper receiving and defining said second passageway, said tipping paper having a plurality of perforations communicating the surrounding air with said second passageway defining an air flow path having a draw resistance to complement said draw resistance of said first passageway whereby for a givendraw ventilation air, in an amount of from about 15 percent to about 60 percent of the total delivered puff volume, and relatively unfiltered smoke eneters the smoker's mouth.
Claim 3
Dependent Claim 35 words
The combination set forth in claim 1 wherein the compacted cellulose acetate tow has a value of from about 2 to about 4 dpf and a value of from about 35,000 to 45,000 total denier.
Claim 4
Dependent Claim 26 words
The combination set forth in claim 1 wherein the fibers of the second passageway are substantially deregistered as opposed to the fibers of the first passageway.
Claim 5
Dependent Claim 26 words
The combination set forth in claim 3 wherein the fibers of the first passageway retain from about 5 to about 25 percent of their original registration.

References Cited (Backward Citations)

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US3396061A Cited
US3348553A Cited
US3313306A Cited
US3405717A Cited
US3630210A Cited
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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) 1980-07-11 1981-01-10 1981-07-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-07-11 1985-01-10 1985-07-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-07-11 1989-01-10 1989-07-12 $7700.00 Window Closed / Lapsed

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