Variable Dilution Filter

This invention relates to smoking articles in general and more particularly to a ventilated cigarette with means to adjust the smoke to ventilation air ratio.

The current trend in cigarette manufacturing has been to reduce the concentration of certain components of smoke. For example, filters made of fibrous materials such as cellulose acetate are used to lower the concentration of particulate matter in the smoke generated in smoking. Ventilation into the filter has been used to further reduce the concentration of particulate matter and also to lower the concentration of gas phase components.

Filtration of the smoke and ventilation into the cigarette filter both affect the flavor of the cigarette. In particular, as ventilation is increased and smoke to ventilation air ratio is reduced, the flavor of the cigarette is reduced. Since the ventilation ratio on most cigarettes is fixed at the factory, a smoker not satisfied with the flavor of a particular cigarette would have no choice but to change brands, when all he was dissatisfied with was the highly diluted flavor of smoke he was receiving.

Prior art methods of componsating for this problem have met with varying degrees of success. Regal et al, U.S. Pat. No. 3,503,406 and Thompson, U.S. Pat. No. 3,359,988 use sliding external mechanical sleeves which must be positioned so that openings in the slidable sleeve are aligned with openings in the filter mouthpiece. These methods add to the manufacturing cost in that an additional piece must be added to each cigarette filter.

Other devices such as those disclosed by Cavelli, U.S. Pat. No. 3,858,587 and Sipos, U.S. Pat. No. 3,486,508 employ devices that must be operated with the smokers teeth as in Cavelli or with the smokers tongue as in Sipos. These methods are not aesthetically pleasing and suffer from a lack of uniformity when mass produced at the rate modern cigarettes are manufactured.

It is, therefore, an object of the present invention to provide a cigarette wherein the smoke to ventilation air ratio may be changed to suit the preference of the smoker.

It is also an object of the present invention to provide a cigarette with variable smoke to ventilation air ratio which is compatible with current high speed cigarette manufacturing equipment.

Yet another object of the present invention is to produce a cigarette with a variable smoke to ventilation air ratio that is aesthetically pleasing to the smoker.

According to the present invention, the foregoing and other objects are attained by providing a smoking articles with a first stage filter which is rigidly attached to the tipping paper at the mouth end of the mouthpiece. A second stage filter element located forward of the first stage element is free to slide axially and may be made to move rearward by tapping the mouthpiece end of the smoking article on a hard surface. Rearward movement of the second stage filter element covers some of the ventilation holes located in the tipping paper between the first stage and second stage filter element which increases the smoke to ventilation ratio thus increasing the flavor of the cigarette.

A more complete appreciation of the invention and many of the attendent advantages thereof will be readily apparent by reference to the follow detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view, partially broken away, of a smoking article according to the present invention;

FIG. 2 is a longitudinal cross-section of the invention shown in FIG. 1;

FIG. 3 is a longitudinal cross-section of the invention shown in FIG. 1 wherein the second stage element has moved partially to the rear;

FIG. 4 is a longitudinal cross-section of another embodiment of the invention; and

FIG. 5 is a longitudinal cross-section of a smoking article according to the present invention with a third stage filter element.

Referring now more particularly to the drawings and specifically to FIG. 1 there is illustrated a preferred embodiment of the invention as it would be used in a smoking article, in this case a cigarette designated generally by the numeral 10. Cigarette 10 has two major parts, smoking cylinder 12 and filter mouthpiece 14.

Filter mouthpiece 14, which is approximately cylindrical in shape, substantially conforms to the cross-sectional size and shape of smoking cylinder 12. Filter mouthpiece 14 consists of a first stage filter element 18 and a second stage filter element 19 enclosed by tipping paper 22. First stage filter element 18 may be of any filtering material, but in the preferred embodiment is cellulose acetate. Plug wrap 20 encloses first stage filter element 18 and is rigidly attached to tipping paper 22. Second stage filter element 19 is similar in construction to the first stage filter element 18, but is not attached to tipping paper 22 and is thus free to move in an axial direction. Filter elements 18 and 19 may be used without plug wrap 20. For example, a nonwrapped acetate filter element, in which the outer surface has been bonded together with heat may be used.

Tipping paper 22 is air impervious and attaches filter mouthpiece 14 to smoking cylinder 12. Ventilation holes 16 in air impervious tipping paper 22 admit outside air to filter mouthpiece 14 in the space between first stage filter element 18 and second stage filter element 19.

As smoking article 10 is consumed, smoke from the burning coal of the cigarette travels through smoking cylinder 12. Air also enters smoking article 10 through ventilation holes 16 and mixes with the smoke in filter mouthpiece 14. In modern, highly diluted, highly filtered cigarettes the flavor of the resulting smoking article may be such that some smokers are not satisfied. In this event, the mouthpiece 14 of smoking article 10 may be tapped on a hard surface. This causes second stage filter element 19 to slide toward first stage filter element 18, as shown in FIG. 3, occluding some of ventilation holes 16. Since ventilation air must now be drawn through ventilation holes 16, porous plug wrap 20, and second stage filter element 19, less ventilation air enters filter mouthpiece 14. Thus, the resulting smoke to ventilation air ratio will be higher than in the cigarette before movement of second stage filter element 19 to the rear, resulting in a more highly flavored cigarette.

FIG. 4 shows another embodiment of the invention in which filter elements 18 and second stage filter element 19 have not been enclosed by a plug wrap. Also in this embodiment, ventilation holes 16 are located at the forward end of filter mouthpiece 14. Thus, ventilation air must travel through second stage filter element 19 resulting in a stronger flavored cigarette. In this embodiment, tapping filter mouthpiece 14 against a hard surface moves second stage filter element 19 towards first stage filter element 18 uncovering ventilation holes 16, thus, decreasing the smoke to ventilation air ratio. Therefore, this embodiment produces a weaker flavored cigarette when the filter mouthpiece 14 is tapped against a hard surface. This embodiment might be useful for changing the ventilation ratio after the cigarette has been partially smoked when the flavor normally becomes stronger as the length of the smoking cylinder 12 decreases.

FIG. 5 shows another embodiment of the invention with a third stage filter element 21. All three filter elements in this embodiment are shown with a nonwrapped acetate filter although here also a wrapped or non-wrapped filter element could be used. First stage filter element and third stage filter element are rigidly attached to tipping paper 22. Second stage filter element 19 is free to move axially in filter mouthpiece 14. This embodiment prevents shifting of the tobacco when filter mouthpiece 14 is tapped since third stage element 21 is rigidly attached directly behind smoking cylinder 12.

The embodiment shown in FIG. 5 may also be used as a detachable cigarette holder. In this case, tipping paper 22 would be more rigid than the earlier embodiments, plastic would be a suitable material, and would not be attached to smoking cylinder 12. When used as a cigarette holder the smoking cylinder would be inserted into mouthpiece 14. Smoke to ventilation air ratio would be adjusted as described below.

It is thus seen that in a cigarette according to the present invention, the smoke to ventilation air ratio may be varied by the smoker simply and effectively. It is also seen that a cigarette according to the present invention is of simple construction and compatible with modern high speed cigarette making machines.