referring now to the embodiment illustrated in fig1 , and 3 , the mouthpiece portion of a cigarette is shown comprising a tobacco column 11 , wrapped in cigarette paper 12 to which is affixed a filter plug 13 by tipping paper 14 . within the tube formed by tipping paper 14 , there is positioned a circular member 15 abutting filter plug 13 and of equal diameter thereto containing a movable flap valve 16 which in the open position of fig1 bends into chamber 17 within the tube . when flap 16 is bent , an opening 18 is provided in member 15 . the contiguous surfaces of member 15 and filter plug 13 may be affixed together by an adhesive or glue to assure that the member is held in the proper position within the tipping paper tube . member 16 is made of material that is substantially air impermeable and , therefore , impervious to the gaseous and particulate vapors drawn through the cigarette such as tars , nicotine , and vapor phase constituents normally present in tobacco smoke . typically suitable materials are paper , preferably heavier gauge cigarette tipping paper , and flexible plastic films such as cellophane , polyethylene , polypropylene , and the like . flap 16 is cut out of the center of member 15 along three sides and bent or folded on the fourth side along line 19 such that it is normally in the open position . the materials employed for member 15 should be sufficiently resilient so that flap valve 16 will return to the open position shown in fig1 from the closed position shown in fig3 when pressure on the valve is removed . operation of the valve is uncomplicated and provides a positive means of controlling volume and rate of draw on the cigarette in any single puff , thus limiting the amount of nicotine available to the smoker . as shown in fig1 arrow 21 indicates the normal path traveled by the smoke through the cigarette starting with tobacco column 11 , through chamber 19 , opening 18 provided by flap valve 16 , and thence through the porous filter medium of filter plug 13 before entering the smoker &# 39 ; s mouth . as long as the pressure drop or volume and rate of draw in any puff is normal , flap valve 16 remains open . however , if the pressure becomes excessive , flap valve 16 closes as shown in fig3 preventing further smoke from reaching the smoker &# 39 ; s mouth in that puff . when the pressure is released at the end of the puff , the flap automatically returns to the open position shown in fig1 again allowing smoke to be drawn through the cigarette on the next puff . in fig4 , and 6 , another embodiment of the invention is shown in which like parts of the cigarette and mouthpiece of fig1 are referred to with like numerals . thus , within the chamber 17 between filter plug 13 and tobacco column 11 is positioned a circular member 22 having a rectangular opening 23 cut in its center section as shown by the dotted lines in fig5 . shoulder 24 at the outer periphery of member 22 is provided to adhesively seal the member to the inner wall of tipping paper 14 and hold it in position within chamber 17 . a flap valve 25 slightly larger than opening 23 is positioned over the opening and glued to member 22 along one side . a bend or crease along line 26 allows the valve to be normally open . the same materials described above to make circular member 15 in fig1 may be used to make member 22 and flap valve 25 . alternately , the entire assembly comprising member 22 and valve 25 may be molded from a plastic polymer material with shoulder 24 extending in both directions to form a tubular piece coextensive in length with the distance between the end of the tobacco column and the filter plug or if a filter plug is not employed of sufficient length to reach the end of the cigarette mouthpiece . as shown more clearly in fig6 when excessive pressure is applied by the smoker in any puff , flap valve 25 closes preventing further smoke from passing through the cigarette , thus limiting the nicotine yield in that puff . a similar embodiment is shown in fig7 and 8 in which a circular opening 27 is provided in member 25 overlaid by a slightly larger circular flap valve 28 glued at tab 29 to member 25 . in this embodiment , the device is made of the same materials and functions in the same manner as the embodiments heretofore described . the pressure drop in a normal puff on a cigarette will vary depending on the smoker between 3 to 10 inches of water at 17 . 5 cc per second air flow . accordingly , and in order to prevent an excessive draw in any one puff on a cigarette or other smoking article , the flap valves of this invention are preferably designed to close whenever the pressure drop exceeds 10 inches of water at 17 . 5 cc per second air flow . of course , it is apparent that they can be designed to close at lower or higher pressure drops depending upon the specific requirements of the smoking article . also , while all of the drawings illustrate the flap valve in combination with a filter plug , it is to be understood that valves according to the invention can be employed with or without a filter and with a variety of smoking articles such as cigarettes , cigars , pipes , etc ., where a smoke control limiting means would be desirable . it will thus be seen from the foregoing description that an improved smoke control device is provided to limit the delivery of nicotine and tar in any single puff on the smoking article to that obtainable in a normal puff . although the invention has been described in conjunction with the preferred embodiments and drawings , they are only illustrative of the invention and it is to be understood that many variations and modifications may be resorted to without departing from the spirit and scope of the invention , as those skilled in the art will readily understand .
an improved smoke control device for smoking articles which contains a valve operative to close off the flow of smoke drawn through the smoking article depending upon the pressure drop or draw rate of each individual puff . preferably , the valve comprises a resilient flap member responsive to the puff pressure drop for restricting or closing off smoke drawn through the smoking article and which will reopen after the pressure is relieved , thereby limiting each puff to a predetermined yield consistent with that obtainable in a normal puff .