US3695274A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piston type cigarette filter
Assignee: Brown and Williamson Holdings Inc
•
Filing: 1970-11-30
•
Granted: 1972-10-03
•
Expires: 1990-11-30
Abstract
Abstract A piston-type mouthpiece for a cigarette or cigarette holder includes an outer tube in which is a slidable cup-like piston with the open end facing the smoker. The piston face has a plurality of perforations which act as a filter. As the perforations become blocked and as the density of puffs increases during the smoking of the cigarette, the vacuum created in drawing on the cigarette gradually draws the piston toward the smoker. As the piston slides toward the smoker, openings in the cylindrical wall of the piston become aligned with openings in the outer tube so that air is drawn from the atmosphere directly into the smoker''s mouth through these openings rather than through the tobacco column.
Inventors
- 👤 Thomas W Summers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:52
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/04; A24D3/041
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
212 words
A filter device adapted to be interposed between the tobacco end and the mouthpiece end of a smoking device comprising: a sleeve forming the outer wrap of the device and having at least one opening in its side wall, a tubular piston slidable in said sleeve and having at least one port in its side wall, the said port being interposed between the said opening and the tobacco end of the device and the the tubular side wall of said piston covering the said opening when the piston is in its initial position, said opening and said port when in registry forming a free air passage when the said piston moves from its initial position toward the mouthpiece end, said opening and said port having predetermined dimensions which increase the air passage area as the said piston moves toward the mouthpiece end, the face of said piston adjacent said tobacco end having a plurality of perforations, said piston being adapted to move axially toward the mouthpiece end in response to a pressure differential across the said face as the smoker draws on the device, whereby the piston will move until sufficient air enters the air passage formed by the overlapping port and opening and there is no pressure differential across the face.
Claim 2
Dependent Claim
212 words
A filter device adapted to be interposed between the tobacco end and the mouthpiece end of a smoking device comprising: a sleeve forming the outer wrap of the device and having at least one opening in its side wall, a tubular piston slidable in said sleeve and having at least one port in its side wall, the said port being interposed between the said opening and the tobacco end of the device and the the tubular side wall of said piston covering the said opening when the piston is in its initial position, said opening and said port when in registry forming a free air passage when the said piston moves from its initial position toward the mouthpiece end, said opening and said port having predetermined dimensions which increase the air passage area as the said piston moves toward the mouthpiece end, the face of said piston adjacent said tobacco end having a plurality of perforations, said piston being adapted to move axially toward the mouthpiece end in response to a pressure differential across the said face as the smoker draws on the device, whereby the piston will move until sufficient air enters the air passage formed by the overlapping port and opening and there is no pressure differential across the face.
Claim 3
Dependent Claim
46 words
The invention of claim 1 wherein the number and size of perforations in the face of the piston shall be such that the resistance of air flow through the piston face is within the values defined by 0.01 -0.1 inches H2O pressure drop at 17.5 cc/sec.
Claim 4
Dependent Claim
22 words
The invention of claim 1 wherein the number of perforations in the face of the piston shall be between seven and 11.
Claim 5
Dependent Claim
19 words
The invention of claim 3 wherein the area of each perforation shall be between 0.1 and 0.7 square millimeters.
Claim 6
Dependent Claim
23 words
The invention of claim 1 wherein the number of ports in the side wall of the piston shall be between one and five.
Claim 7
Dependent Claim
29 words
The invention of claim 1 wherein the overlapping ports and openings shall form an air opening having a total area ranging in size from 0.25 to 5 square millimeters.
Claim 8
Dependent Claim
46 words
The invention of claim 1 wherein the ports shall be so shaped that the air opening formed by the overlapping ports and openings shall increase in dimension as the piston slides from its initial position to a position where the openings fully register with the ports.
Claim 9
Dependent Claim
20 words
The invention of claim 7 wherein the ports are triangles with their apexes pointing in the direction of the smoker.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |