Cigarette

Abstract

A cigarette comprising a filter, a roll of tobacco, a wrapper surrounding the filter and tobacco which has a plurality of air ingress openings in an area adjacent to but ahead of the filter, and means overlying said openings to impede the ingress of air therethrough until the cigarette has been burned away to predetermined position and then automatically to uncover the openings for ingress of air. The atmospheric air blending with the smoke generated by burning the tobacco cools the smoke and precipitates condensibles which are caught and held by the filter.

Description

BACKGROUND OF THE INVENTION

A considerable body of data has been collected which many skilled workers in the health field have interpreted to mean that cigarette smoking is damaging to health. While the products of combustion of a cigarette are extremely complex, it is a widely held view that condensibles, including tars and nicotine, are among the products of combustion which are injurious to health. Many proposals have been made to provide cigarettes which have a lower content of tar and nicotine in the smoke that enters the smokers system than the cigarettes which were commonly used at the time the aforementioned body of data was accumulated. None of these proposals has solved the problem satisfactorily. An earlier invention of the present inventor which is described and claimed in U.S. Pat. No. 3,441, 028 granted Apr. 29, 1969 relates to apparatus for and method of removing condensible compounds from tobacco smoke by use of a thermoresponsive device to uncover aerating openings leading to the atmosphere to blend air with tobacco smoke when a cigarette is partially burned away. Specifically a U-shaped bimetallic element or spring is disclosed in a smoke passage of a molded plastic insert between the tobacco and the filter which has lateral passages connecting the smoke passage to the atmosphere that are closed by the arms of the spring. When the temperature of smoke passing over the spring is high enough, the arms are caused to move away from and open the lateral passages to admit air that blends with the tobacco smoke, cools it and causes condensibles to precipitate.

Comparative tests have been made on cigarettes from the same pack with and without the aerating device or precipitator described in U.S. Pat. 3,441,028. These tests were carried out in a smoking machine under standard test conditions. The weight of condensibles in the smoke passing through the cigarette provided with the aerator or precipitator was a small fraction of the amount from cigarettes without it. The rise in temperature of the smoke leaving the cigarette from the first to the last puff was found to be substantially smaller in the case of cigarettes having the precipitator installed therein. These advantages, moreover, were obtained without substantially altering the taste of the cigarette.

The commercial manufacture of cigarettes made in accordance with the invention of U.S. Pat. No. 3,441,028 presents some problems which are expensive to solve, particularly the automatic bending and assembling of the U-shaped spring with the molded plastic element and the incorporation of this element in multiple plugs such as are made by combiners for use in automatic cigarette making machinery.

The present invention has substantially all of the benefits of the invention of U.S. Pat. No. 3,441,028 mentioned above but without the difficulties of making and assembling the precipitator and incorporating it in cigarettes by the use of automatic machinery.

SUMMARY OF THE INVENTION

The cigarette of the invention comprises a filter, a roll of tobacco, a wrapper surrounding the filter and roll of tobacco having a plurality of air ingress openings in an area adjacent to but ahead of the filter, and means overlying said openings to impede the ingress of air therethrough until the cigarette has been burned away to a predetermined position and then automatically to uncover such openings for the ingress of air. The air which flows in through these openings blends with smoke generated by burning the tobacco to cool the same and precipitate condensibles which are then caught and held in the filter downstream from the place of mixing. Preferably this uncovering of the air ingress openings takes place progressively from a minimum to a maximum as the burning away of the cigarette proceeds. The means preferably comprises a band of resilient sheet material, e.g., paper, plastic, and the like, which encircles and is held against the wrapper by adhesive at the downstream end and on an area of the upstream end. When the cigarette has burned beyond the adhesive at the upstream edge, the natural resilience of the sheet material causes the upstream end to lift away from the wrapper and reveal the air ingress openings beneath. In order to provide for gradual and progressive increase in the volume of air flowing through the ingress openings during the draw on the cigarette, as it burns, the adhesive at the upstream end is arranged in a diagonal stripe or series of spots of adhesive running from the upstream corner diagonally toward the downstream end at any desired angle.

If desired, means may be provided internally of the cigarette to assure and/or assist the blending of air with the cigarette smoke during the draw. Such means may be a simple disc with a central aperture, a mixing zone such as may be provided by a plug of charcoal granules or a molded plastic insert operating on the principles of fluidics.

Brief Description of the Drawing

FIG. 1 is an exploded plan view of a cigarette provided with air ingress openings in an area ahead of but adjacent to a filter and a cover piece of flat resilient sheet material having adhesive stripes thereon prior to the application thereof to the cigarette to cover said openings;

FIG. 2 is a plan view of a cigarette with the cover piece adhering to the cigarette closing said air ingress openings;

FIG. 3 is a cross section on an enlarged scale on the line 3--3 of FIG. 2 with the thickness of the cigarette wrapper and the cover piece exaggerated to show the structure and relationship of the parts;

FIG. 4 is a perspective view of a cigarette when it has burned down far enough to release a part of the cover piece to uncover some of the air ingress openings;

FIG. 5 is a longitudinal section of another embodiment of the invention using an apertured disc between the filter and the tobacco to intensify the blending of air flowing into the cigarette through the air ingress opening with the smoke generated by the burning of the cigarette;

FIG. 6 is a fragmentary longitudinal section of a further embodiment of the invention applied to a cigarette having a charcoal filter with air ingress openings through the wrapper in the area surrounding the charcoal filter, and, optionally, additional openings in the wrapper ahead of the short filter plug upstream from the charcoal granules; and

FIG. 7 is a fragmentary longitudinal sectional view of still another embodiment of the invention utilizing an aerator between the filter and the tobacco to intensify the mixing of the air flowing through ingress openings into a mixing chamber passing longitudinally through the aerator utilizing the principles of fluidics to precipitate condensibles to be caught and held in the downstream filter.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS OF THE INVENTION

Referring to FIG. 1, a cigarette referred generally by reference numeral 1 comprises a filter 3, a roll of tobacco 5,a cigarette wrapper 7 having a plurality of ingress openings 9 in an area ahead of but adjacent to the filter 3. The filter 3 may be any suitable material such as the filter materials now widely used in commercial filter cigarettes. The function of the filter is to remove from the gases passing through it all condensibles which have been precipitated in the liquid or solid form by the time the smoke leaves the filter. In general such filter materials are made of cellulose and its derivatives but any filter material functioning as described may be used in the present invention.

The tobacco and wrapper may likewise be made of customary blends and materials in accordance with existing cigarette technology. The only difference is that ingress openings are provided in the cigarette wrapper as illustrated. These openings may be preformed in the cigarette wrapper or they may be formed in the finished cigarette as it comes from existing cigarette making machines.

The means for covering the ingress openings to impede the ingress of air therethrough is preferably a resilient sheet material such as paper, plastic and the like, which has the capacity for remembering the shape in which it was manufactured and to which it returns from any other shape when the force holding it in any other shape is released. Such a piece of sheet material is shown in FIG. 1 by reference numeral 11 and it is provided with a peripheral stripe of adhesive 13 on at least the downstream edge 12 and end 13 of the cover piece. If desired, to assure more complete coverage of the ingress openings, the stripe of adhesive may also be provided at the periphery of the upstream edge of the cover piece 11 in the region designated by reference numeral 14. The cover piece 11 is also provided with at least a spot of adhesive in the corner formed by the upstream end 17 and the upstream edge 19, and preferably with a diagonal stripe 15 of adhesive extending from that corner toward the opposite corner as illustrated. By "stripe" is meant not only a continuous band of adhesive but also a sequence of spots or drops of adhesive.

The length of the cover piece from the upstream to the downstream edge is preferably sufficient to cover substantially all of the air ingress openings so that from a practical standpoint little if any air is drawn into the cigarette through the ingress openings prior to the release of the upstream end 17 to lift away from the cigarette wrapper as hereafter described. The width of the cover piece from the upstream end to the downstream end is at least sufficient to encircle the cigarette wrapper and preferably slightly longer so as to provide on overlap 21 as seen in FIGS. 2 and 3. The cover piece, with adhesive thereon, is then wound around and stuck to the cigarette wrapper 7 as shown in these figures.

When a smoker lights up a cigarette constructed as illustrated in FIGS. 1, 2 and 3, it behaves exactly like a cigarette without the ingress openings and cover piece until the cigarette has burned down to the upstream edge of the cover piece. Any further burning destroys the adhesive bond between the cover piece and the cigarette wrapper along the areas covered by stripes 14 and 15 and releases the upstream end 17 to lift away from the cigarette wrapper 7, as illustrated in FIG. 4, which uncovers some of the ingress openings and permits air to flow therethrough during the draw on the cigarette. It will be apparent that this lifting of the upstream end 17 of the cover piece 11 away from the cigarette wrapper 7 may be a progressive thing if the adhesive 15 is a diagonal stripe as illustrated in the drawings.

The blending of the cool atmospheric air with the hot smoke of the cigarette cools the smoke, causing condensibles therein to precipitate in liquid or solid form and as the gas stream moves into and through the filter 3 these precipitated condensibles are caught and held so that the smoke entering the smokers system contains a substantially lower amount of condensibles than the smoke from the same cigarette would contain without the aeration in accordance with the present invention.

The embodiment of the invention illustrated in FIG. 5 of the drawing differs from the embodiment described above only in the inclusion therein of a disc 23 having a diameter corresponding to the diameter of the filter and also having an air passage 25 therethrough. The diameter of this air passage can be adjusted so as to considerably increase the velocity of flow of the gas stream but without substantially increasing the draw, which many smokers find objectionable. The presence of the apertured disc contributes to the mixing of the smoke with the air flowing through the ingress openings and thereby increases the amount of condensibles precipitated before the smoke leaves the filter.

The embodiment of the invention shown in FIG. 6 illustrates how the principles of the invention can be applied to a charcoal filter cigarette. In this embodiment of the invention the cigarette comprises a filter 3, tobacco 5, a wrapper 7 as described for the embodiments of FIGS. 1, 2, 3 and 4, but with the presence also of a plug of charcoal granules 27 and a short plug of filter material 29 between the charcoal and the tobacco to maintain the filter stick assemblage used in the commercial manufacture of this type of cigarette. In this embodiment of the present invention the cigarette wrapper 7, is provided with air ingress openings 9 at least in the area of the wrapper which surrounds the charcoal granules 27. Additional openings 9 may also be provided in the cigarette wrapper 7 ahead of the plug 29. In this embodiment of the invention the cover piece 11 is long enough to extend from the forward end of the filter 3 well beyond the front end of the plug 29. This arrangement is necessary, even if air ingress openings 9 are provided only in the area of the wrapper surrounding the charcoal granules 27, in order that the burning away of the cigarette will release the upstream edge 17 of the cover piece at the predetermined place in the burning away of the cigarette.

In the form of the invention illustrated in FIG. 7, an aerator or precipitator 31 is provided which has an axial passage 33 running from the front end to the back end thereof which provides a mixing chamber for smoke passing therethrough and for air entering this passage from radial passages 35 which extend from the axial passage 33 to the cigarette wrapper 7. The wrapper 7 is provided with air ingress openings 9 communicating with the passages 35. In this form of the invention the air flowing in through the passages 35 impinges with jet force on the stream of smoke flowing axially through passage 33 which sets up great turbulence and, by fluidic action, intensifies the precipitation of condensibles which are then caught and held in the filter 3 as the smoke flows therethrough.

Although the invention has been described in conjunction with a number of preferred embodiments of the invention, modifications and variations can be made therein without deviating from the principles of the invention described herein. adhesive

Claims

I claim:

1. A cigarette comprising:

a. a filter;

b. a roll of tobacco;

c. a wrapper surrounding said filter and roll of tobacco having a plurality of air ingress openings in an area adjacent to but ahead of said filter; and

d. resilient sheet means including a bond that burning tobacco destroys encircling the cigarette overlying said openings to impede the ingress of air therethrough until the cigarette has been burned away to a predetermined position, said means, upon destruction of said bond, moving away from said wrapper to uncover openings for ingress of air therethrough to blend with smoke generated upstream from the openings by burning the tobacco to cool the smoke and precipitate condensibles therein to be deposited in said filter.

2. A cigarette as set forth in claim 1 in which said bond is adapted for progressive destruction permitting progressive movement of said means for uncovering increasing numbers of said openings progressively as the burning away of said cigarette proceeds.

3. A cigarette as set forth in claim 1 in which said bond for holding said resilient sheet means in position overlying said openings includes adhesive at the downstream end and at the upstream end of said sheet means.

4. A cigarette as set forth in claim 3 in which said adhesive at the upstream end extends helically toward the filter whereby said resilient sheet means is progressively released to uncover an increasingly larger number of openings as the burning of the cigarette proceeds.

5. A cigarette as set forth in claim 1 in which said resilient means is a normally flat sheet of paper.

6. A cigarette as set forth in claim 1 in which said resilient means is a normally flat sheet of plastic.

7. A cigarette as set forth in claim 1 having means between the filter and tobacco to promote blending of air with the smoke when ingress openings are uncovered.

8. A cigarette as set forth in claim 7 in which said means between the filter and tobacco is an apertured disc.

9. A cigarette as set forth in claim 7 in which said means between the filter and tobacco includes a charcoal plug.

10. A cigarette as set forth in claim 7 in which said means between the filter and tobacco is an aerator having an axial smoke passage and radial air ingress passages.