in a preferred embodiment , the device of the present invention , as shown in fig1 , includes a cylindrical container ( 1 ) having a predetermined inside diameter . the container has a threaded neck portion ( 2 ) and is open at one end ( 3 ). preferably , it is also open at its other ( lower ) end ( 25 ) to facilitate assembly of the device and filling it with a cosmetic composition ( not shown ). the container ( 1 ) is preferably injection molded to control its inside diameter . an exteriorly threaded drive screw ( 4 ) having a bore ( 30 ) open at least at its upper end is disposed inside the container along the container &# 39 ; s central vertical axis . as used herein the term “ upper ” is intended to mean that end or portion of the device , or the end or portion of any component part of the device , proximate to , towards , or in the direction of cap ( 14 ) ( see fig3 ). the term “ lower ” is intended to mean that end or portion of the device , or the end or portion of any component part of the device , proximate to , towards , or in the direction of end cap ( 12 ). the drive screw ( 4 ) is preferably hollow through its entire length , as shown in fig1 . the upper end of the drive screw has a round external cross section which fits within the inside diameter of the container neck ( 2 ), as best shown in fig3 . the container has a small outward step or lip ( 35 ) within the neck ( 2 ), which functions as a stop for the drive screw ( 4 ), while permitting the screw to rotate about the container &# 39 ; s central vertical axis . within the upper end of the bore ( 30 ) of the drive screw , a shaped interior ( 29 ), shown to be hexagonal in fig1 b , is provided , defined herein as the drive in the drive screw bore that is adapted to receive a positive rotational drive from another component , which can be assembled within the cap . the drive ( 29 ) in the top of the drive screw bore is also referred to herein as the complementary drive ( 29 ). a preferably molded piston ( 5 ) is assembled to the drive screw ( 4 ) and is engaged with the external threads ( 8 ) of the drive screw ( 4 ). the piston ( 5 ) has a threaded interior bore ( 24 ), which engages the drive screw threads ( 8 ). the flexible piston ( 5 ) fits within the inside diameter of the container ( 1 ) with a designed interference fit that creates a peripheral seal . assembled at the lower end of the drive screw ( 4 ) is a cylindrically shaped valve ( 6 ), which also fits within the inside diameter of the container ( 1 ) with a designed interference fit to create a peripheral seal . the valve ( 6 ), shown in greater detail in fig1 a , has a smooth bore central portion ( 42 ) that fits closely around the base of the drive screw ( 4 ) in the non - threaded portion ( 7 ) of the drive screw ( 4 ). the fit allows the valve ( 6 ) to move axially about the drive screw ( 4 ). the valve is also free to move rotationally on the portion ( 7 ) of the drive screw . the bore ( 42 ) of the valve ( 6 ) has a conical seal or beveled surface ( 9 ) which mates with a conical valve seat or beveled surface ( 10 ) around the diameter of the drive screw ( 4 ) at the upper end of the non - threaded portion ( 7 ). the valve seat ( 10 ) preferably is a radial extension on the drive screw ( 4 ) whose diameter is greater than the diameter of the drive screw ( 4 ). a biasing element , such as compression spring ( 11 ), is fitted behind the valve ( 6 ) and is seated within a recess in the base of the valve . although a compression spring is preferred , any biasing element can be used ; for example an elastomeric material having a memory . an end cap ( 12 ) fits inside the open end ( 25 ) of the container ( 1 ) and , as shown in fig3 , the biasing element ( 11 ) fits within the inside diameter of the end cap ( 12 ). the end cap ( 12 ) has a sufficient interference fit with the container ( 1 ) to create a seal as well as continually compress the spring ( 11 ) between the interior of the end cap ( 12 ) and the valve ( 6 ). the end cap ( 12 ) also functions to create a solid mechanical end for the container ( 1 ) in addition to performing the function of an axle for the bottom end of the drive screw ( 4 ). the biasing element ( 11 ), which is fitted and compressed between the valve ( 6 ) and the end cap ( 12 ), keeps the conical valve seal ( 9 ) tight against the conical valve seat ( 10 ) on the drive screw ( 4 ). below the conical valve seat ( 10 ) on the drive screw ( 4 ) and towards the end cap ( 12 ), are a plurality of apertures ( 13 ) ( preferably two or three ), which are radially and equally distributed about the diameter of the drive screw ( 4 ). the apertures ( 13 ) extend through the wall of the drive screw and are preferably holes 0 . 060 ″ in diameter . the diameter of the holes is adjusted depending upon the viscosity and flow characteristics of the composition that is to be housed in the device . as shown in fig2 , the cap ( 14 ) is molded and shaped to match the container ( 1 ) outside diameter and has a series of internal splines ( 39 ) and an undercut bead that engage splines ( 38 ) provided along the lower periphery of threaded cap insert ( 15 ) to create an interference fit . the cap insert ( 15 ) has internal threads ( 16 ), which engage the external threads of the container neck ( 2 ). an applicator rod ( 17 ) that is preferably round in cross section and has an upper flange ( 18 ), a cylindrical upper section ( 31 ), and a preferably hexagonal section ( 21 ) is fitted into and through the cap insert ( 15 ). hexagonal section ( 21 ) is herein defined as the cap drive and is complementary to the drive in the hexagonal bore ( 29 ) of the drive screw . when engaged , rotational motion from the applicator rod ( 17 ) is transferred to the drive screw ( 4 ). the resultant assembly is fitted into the cap ( 14 ) so that the rod flange ( 18 ) is trapped between the cap ( 14 ) and cap insert ( 15 ) and is free to rotate but not move axially . as is more clearly shown in fig4 , about the axis of the upper end of the rod ( 17 ), but between the flange ( 18 ) and the cylindrical upper section ( 31 ), are at least one , preferably a series of outward ratchet teeth ( 19 ), which correspond with at least one , preferably a plurality , of angularly offset flex tabs ( 20 ) ( preferably two to three tabs ) on the upper end of the cap insert ( 15 ). the ratchet system is designed to drive the rod ( 17 ) in one direction and free wheel in the other direction . preferably the ratchet engages when the cap assembly is rotated counterclockwise and free wheels or ratchets when the cap assembly is rotated clockwise . lower end of the cylindrical section ( 31 ) has a lip ( 32 ) that creates a seal on the top of lip ( 35 ) of the open end ( 3 ) of the neck ( 2 ) of the container ( 1 ). the rod ( 17 ) also has an extension comprising a long slender shaft ( 22 ) having an orifice ( 23 ) at its lower end for insertion of an applicator ( 37 ), for example , a mascara brush . the shaft ( 22 ) and applicator ( 37 ) are designed to fit inside the internal bore of the drive screw ( 4 ). in assembly , the piston ( 5 ) is threaded onto the drive screw ( 4 ) and positioned at the top end of the threaded portion ( 8 ) of the drive screw ( 4 ). the drive screw / piston assembly is inserted into the container ( 1 ) housing through its open end ( 25 ) so that the upper end of the drive screw ( 4 ) is fitted within the inside diameter of the container neck . the cap assembly of fig2 ( rod ( 17 ) with applicator ( 37 ), cap insert ( 15 ), and cap ( 14 )) is screwed clockwise onto the threaded neck portion ( 2 ) of the container ( 1 ). the container / cap assembly is turned upside down to enable the cosmetic composition to be filled into the container through the open lower end ( 25 ) of the container such that the composition resides in the annular compartment between the outside diameter of the drive screw ( 4 ) and the internal diameter of the container ( 1 ) and from the base of the piston ( 5 ) up to the conical valve seat ( 10 ) on the drive screw ( 4 ). the valve ( 6 ) is then assembled onto the drive screw ( 4 ). as previously mentioned , the valve ( 6 ) and the piston ( 5 ) each provide a tight interference fit with the inside wall of the container ( 1 ), and accordingly seal the composition within the annular compartment . the biasing element ( 11 ) and end cap ( 12 ) are then placed into the container , to complete the assembly of the device . the end cap ( 12 ) is pushed into the container , up to a stop inside the container . the assembled dispenser is shown in its initial closed position in fig5 a . in this closed position the piston ( 5 ) is shown at the top of the threaded portion ( 8 ) of the drive screw ( 4 ). similarly , the valve ( 6 ) is seated against the valve seat ( 10 ), and the valve ( 6 ) covers the aperture ( 13 ). accordingly , composition is contained in annular compartment ( 50 ). when the end - user unscrews the cap ( 14 ) to open the dispenser ( shown by the counterclockwise arrow a in fig5 b ), the tabs ( 20 ) on the cap insert ( 15 ) engage the ratchet teeth ( 19 ) on the rod ( 17 ), and cap rotational motion is transferred to the rod ( 17 ) as the cap ( 14 ) is unscrewed from the container neck ( 2 ). the cap drive , e . g ., the hexagonal male section ( 21 ) of the rod ( 17 ), with which the complementary drive ( 29 ) within the bore ( 30 ) of the drive screw ( 4 ), e . g ., the female end of the drive screw , is cooperatively engaged before and while the cap ( 14 ) is being unscrewed from the dispensing device , transfers rotational motion from the rod ( 17 ) to the drive screw ( 4 ). as the drive screw ( 4 ) is rotated about its fixed axis , the piston ( 5 ) is driven downward ( arrow b in fig5 b ) in an unscrewing manner towards the valve ( 6 ), reducing the volume of the annular compartment ( 50 ) and increasing the pressure on the composition in the annular compartment . in response to this increase in pressure , the valve ( 6 ) moves in the direction of the biasing element , spring ( 11 ), further compressing the biasing element ( arrow c in fig5 b ). as the conical valve seal ( 9 ) moves away from the conical valve seat ( 10 ), the composition flows through the apertures ( 13 ) in the side of the drive screw ( 4 ) and enters the interior chamber ( bore ( 30 )) of the drive screw ( 4 ), where the applicator is housed in its rest position . as a dose of composition flows through the apertures into the chamber , the pressure in the annular compartment ( 50 ) is reduced , allowing the compressed biasing element ( 11 ) to elongate and move the valve ( 6 ) back to its rest position against the conical valve seat ( 10 ), thus closing the system . at this time , the cap threads ( 16 ) have been unscrewed from the container ( optimally , approximately two full rotations ) and the cap ( 14 ) is disengaged from the container neck threads ( 2 ). as the cap ( 14 ) is pulled axially away from the container , the hexagonal rod shaft ( 21 ) is also disengaged from the complementary drive ( 29 ) in the bore ( 30 ) of the drive screw ( 4 ), and the applicator ( 37 ) axially travels the full interior length of the drive screw ( 4 ). preferably the applicator ( 37 ) interferes with an optionally provided wiper area , preferably comprising a reduced orifice ( 24 ), situated in communication with the drive screw ( 4 ). this action allows the single dose of composition to be evenly distributed over the length of the applicator ( 37 ). the end - user applies the composition , as required , then reinserts the applicator / cap assembly in the container / drive screw . as the threads of the cap , or more specifically of the cap insert , engage the container threads , the cap is turned in a clockwise direction to replace the cap on the unit . the hexagonal male section of the rod engages the drive screw but the cap insert tabs and rod ratchet system allow the rod to free wheel within the cap due to the inherent friction of the piston . the drive screw is not driven during cap replacement . the piston ( 5 ) remains stationary in the position to which it was advanced during the removal of the cap ( 14 ). the piston ( 5 ) will similarly advance downwardly with each subsequent use of one dispenser ( i . e ., removal of the cap ), until the piston ( 5 ) is proximate the conical valve seal ( 9 ). the components of the device of the present invention may be made of any number of materials , especially from molded plastic materials using conventional plastic molding methods appropriate for the selected material . the container ( 1 ), end cap ( 12 ) and cap ( 14 ) can be made of , but are not limited to , for example , polyester , polystyrene , nylon or high molecular weight polyolefin . polyethylene terephthalate ( pet ) and poly ( cyclohexylene dimethylene cyclohexanedicarboxylate ) ( pcta ), a copolyester of cyclohexane dimethanol ( chdm ) and terephthalic acid ( ta ), are preferred , particularly when the device is to house a post - foaming composition . preferably , the material or materials selected to fabricate the container ( 1 ), end cap ( 12 ) and cap ( 14 ) should allow for aesthetic consistency of the appearance of the assembled device . most preferably , the material or materials should be such that it is possible for the end caps ( 12 ) and the container ( 1 ) to be ultrasonically sealed together . the drive screw ( 4 ), cap insert ( 15 ) and rod ( 17 ) are preferably made of nylon , acetal , polyphenolyne sulfide ( pps ), polyester sulphone , or polypropylene composite polymer . acetal is preferred , particularly when the device is to house a post - foaming composition . the piston ( 5 ) and valve ( 6 ) should preferably be made of a softer more resilient material such as certain grades of polyethylene , elastomeric polyester or polypropylene . low density polyethylene ( ldpe ) is preferred , particularly when the device is to house a post - foaming composition . although the rod ( 17 ) can be employed for applying the composition housed in the device to the face , lips , skin , hair , etc ., an accessory applicator can be employed . examples of suitable accessory applicators include , but are not limited to : twisted wire brushes , molded brushes , foam pads , flocked tipped applicators , staked fiber brushes , combs and plastic spatulas . the accessory applicator can be mounted on the rod , for example , by providing the accessory applicator with an extension that fits within the orifice ( 23 ) of the shaft ( 22 ) of the rod ( 17 ).
a drive screw having an axial bore is disposed within a tubular container . a cap for closing the container has mounted therefrom an applicator that is insertable in the bore of the drive screw . a first seal and a second seal , on the drive screw , form with the inner wall of the container and the outer wall of the drive screw an annular compartment for housing a cosmetic composition . a normally closed channel is provided between the compartment and the bore of the drive screw . a drive on the cap and a complementary drive on the drive screw cooperate with the first seal and the second seal to decrease the volume of the compartment in which the composition is housed each time the container is opened by removing the cap . a valve opens the channel in response to the decrease in volume in the compartment when the cap is removed so as to permit composition to flow through the channel into the bore of the drive screw to contact the applicator .