Roll-on applicator with sharp sealing ring
BACKGROUND OF THE INVENTION 
     The present invention relates to a roll-on applicator of the type used to apply a liquid to a body surface. More particularly, the invention is directed to an improvement in an applicator ball-holding fitment, and improved means by which the applicator ball is positively sealed against a well-defined, firm, sealing ring when the cap is applied to the container as a closure therefor. 
     Ball-retaining fitments of the general type in which the present invention finds utility are well known in the art. For the most part, such prior art structures include sealing suraces against which the roll-on ball is stressed in order to seal the container against fluid loss or spillage during periods of non-use. Such prior art devices also include mechanical means by which the applicator ball is urged upwardly to clear the seat and to establish a fluid passage, when the closure or top is removed from the assembly. Additionally, such prior art structures also include mechanical means by which the ball is forcibly pushed downwardly to engage and bear against the sealing surface when the container is closed by application of the top. 
     In accordance with the present invention it has been discovered that there are important, critical relationships between the several mechanical elements which constitute the means by which the applicator ball is maintained in its various functional positions. It has been established, in accordance with the invention that only through adherence to precise, specific mechanical parameters and structural configurations can the operation of the fitment assembly be optimized. For example, prior art fitment structures have commonly utilized applicator ball sealing surfaces which are generally annular planar faces against which the ball abuts tangentially. In cooperation with such sealing faces, the prior art structures have also taught the use of substantially rigid and inflexible means by which the ball is pressed into engagement against the &#34;planar&#34; sealing surface. Such constant, positive pressure has the undesirable effect of inducing cold flow in both the applicator ball and the contacting sealing surface. As a result, surface irregularities develop in the ball and in the ball-contacting surface itself. These irregularities obviate effective subsequent sealing. 
     An additional structural deficiency of many of the prior art assemblies is that they fail to provide effective spring elements for elevating the ball to a position free of the sealing seat, with the result that the free-flow of liquid past the applicator ball is impaired. It is an important feature of the present invention that the above and other shortcomings and deficiencies of prior art applicator ball fitment constructions are obviated by providing an assembly in which each of the requisite functions is ensured through the use of a novel combination of intercooperating mechanical elements. These elements include spring tensioning support means for the applicator ball in combination with spring pressure elements for seating the ball, and a positive sealing wedge or ring against which the ball is resiliently secured. 
     A specific object of the invention is to provide a cap or closure with flexible pressure-applying fingers which exert an axial pressure against the applicator ball when the cap is in its top-closing position to force the ball downwardly and inwardly into the fitment to seat, in fluid sealing engagement, against the sealing ring of the fitment. 
     A related object of the invention is to provide such flexible pressure-applying fingers which will accommodate and compensate for any dimensional variability in tolerance between the fitment and the sealing ring so that the fluid-tight seal of the assembly will always be effective. 
     Another specific object of the invention is to provide a fitment which includes relief spring elements to bias the applicator ball upwardly and position the ball to clear the sealing ring so that an unpaired fluid passage is provided for application of the liquid to the surface to be treated. 
     A related feature of the invention is that with the cap removed from the assembly, spring-like elements engaging the undersurface of the applicator ball urge the ball upwardly to abut and to seal against a ball-encircling band at the mouth of the fitment to prevent spillage of fluid from the container. Inversion of the assembly and application of slight pressure against the ball serves to displace the ball from the sealing band and to permit fluid flow from the container. 
     Other and further objects, advantages, and features of the invention will be evident from the following description considered in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a dispensing container of the type in which the present invention finds utility, and showing the cap or closure applied thereto; 
     FIG. 2 is a view similar to that shown in FIG. 1, but with the cap removed to show the applicator ball and the embracing fitment; 
     FIG. 3 is a front elevational view of the fitment, with the applicator ball removed; 
     FIG. 4 is a top plan view of the fitment showing the spring fingers for supporting the applicator ball; 
     FIG. 5 is an enlarged cross-sectional view taken substantially on the lines 5--5 of FIG. 3 and showing the spring support fingers and the sealing ring of the invention; 
     FIG. 6 is a planned view of the closure of the container, taken substantially on the lines 6--6 of FIG. 2 and showing the spring fingers which bear upon the applicator ball to seat the ball against the sealing ring when the container is closed; 
     FIG. 7 is an enlarged cross-sectional view taken substantially on the lines 7--7 of FIG. 2 and showing the applicator ball biased upwardly by the spring fingers to clear the sealing ring and to establish an annular fluid passage from the interior of the container to the applicator surface of the ball; and 
     FIG. 8 is an enlarged cross-sectional view taken substantially on the lines 8--8 of FIG. 1 and showing the cap or closure of the assembly in place with the pressure fingers of the closure cap bearing down upon the applicator ball to displace the ball-supporting spring elements and to seat the ball agaist the wedge-like edge of the sealing ring. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The aims and objects of the invention are accomplished by providing a fitment which includes integrally formed ball support elements resiliently biasing the ball upwardly, and which also includes an integrally-formed sealing ring above which the applicator ball is supported by the biasing elements. The critical functional elements of the assembly also include a plurality of pressure-applying fingers which are integrally formed on the under surface of the top or closure element to project downwardly and to bear upon the applicator ball when the cap is applied in position, thereby to urge the ball into firm yet resiliently tensioned sealing engagement against the sealing ring to prevent escape of liquid from the container during periods of non-use. Significantly, the sealing ring is so formed physically that it presents a relatively sharp and well-defined edge or annular apex which sealingly engages the surface of the applicator ball when the cap is positioned in place to close the container. 
     Referring now to the drawings, a preferred embodiment is shown for purposes of illustrative disclosure. In the specific form of the invention depicted, the container or bottle 10 is preferably of glass or of a relatively rigid plastic composition such as linear polyethylene. The neck 14 of the container 10 terminates at its upper open end in an annular collar 18 to which a plastic fitment 20 is attached in snap-fit over-coupling engagement, as shown in FIG. 7. Positive intercoupled securement between the fitment 20 and the neck 14 of the container 10 is assured by engagement of the collar 18 of the neck within a cooperating annular groove or channel 24 formed in the sleeving lower portion 26 of the fitment 20. 
     The fitment 20 is generally cylindrical in form, including a wall 38 which is constricted somewhat at its upper open end 30 to form a ball-contacting band 32. The plastic of the fitment is sufficiently resilient to permit the forcible insertion of an applicator ball 34 through the constricted mouth 36 of the fitment, as shown in FIG. 7. As held within the fitment 20, the ball 34 bears resiliently against spring-like support elements 40 which are integrally formed with the fitment 20 to project inwardly of the internal wall 42 of the fitment, the support elements 40 constituting, in the preferred embodiment of the invention shown (FIG. 4) a plurality of circumferentially disposed spring-like plates 40 which, when the closure cap of the assembly is removed, bias the applicator ball upwardly to establish a condition under which fluid may flow from the container and through an annular passage 44 between the lateral curved surface 46 of the applicator ball 34 and the inner surface 48 of the embracing cylindrical wall 28 of the fitment 20, and then through the annular port or mouth 36 between the ball 34 and the band 32 when the applicator ball 34 is brought into engagement with a surface to be coated. 
     With the closure cap of the assembly removed, and in the absence of contacting engagement between the applicator ball 34 and a surface to be coated, the ball 34 is biased upwardly by the spring plates 40 to engage the circumambient sealing lip or band 32, thereby to prevent uncontrolled discharge of liquid from the container 10. 
     The method by which the container 10 is sealed during storage periods of non-use to prevent liquid evaporation or spillage is a critical feature of the present invention. The fitment 20 is integrally formed, at a horizontal plane which is below a horizontal diametric plane of the applicator ball 34 with a novel sealing ring, rib or rim 52. The ring 52 defines a relatively sharp edge-like rim formed at a juncture of a pair of angled, intersecting annular faces 54 and 56 of the fitment 20 projecting from and converging inwardly of a bounding internal wall 60 of the fitment 20 and defining a radially inwardly directed, tapered annular wedge terminating in a ball-encircling apex. 
     The manner in which the container is sealed through stressed interengagement between the applicator ball 34 and the edge-like sealing ring 52 is indicated in FIG. 8. As shown, the neck 64 of the bottle 10 is formed with screw threads 66, and the cap or closure 70, which is a generally cylindrical section having a closed vaulted dome, is formed at a lower inner wall portion with internal threads 78 adapted to engage and mesh with the external threads 66 of the fitment 20 so that the cap 70 may be threadedly secured to the neck 64 of the container 10. 
     As shown in FIGS. 6 and 8, the vaulted dome 74 of the closure cap 70 is formed on an internal top surface thereof with a plurality of downwardly projecting tapered flexible fingers 80 which are inclined outwardly from a vetical axis of the closure cap to flex and to bear resiliently upon the applicator ball 34 and to press down upon and to seat and to center the ball 34 against the sealing ring 52 when the closure cap 70 is threadedly secured in place on the container 10. The downward pressure of the fingers 80 in the closing process is sufficent to displace the spring plates 40 downwardly to permit the ball firmly and positively to seat against the sealing ring 52, all as clearly indicated in FIG. 8. 
     The pressure-applying fingers 80 are annularly spaced with respect to a longitudinal axis of the container to define an axially symmetrical circular locus ensuring that the pressure applied to the top surface 84 of the ball 34 will be radially equalized and will cause the ball to center within or against the sealing ring 52. Further to ensure even distribution of pressure and the proper sealing of the applicator ball 34 with the edge of the ring 52, the ball-contacting free ends 86 of the fingers 80 are rounded as at 86, to minimize friction. While any plural number of pressure fingers 80 may be used, three such symmetrically disposed fingers are preferred. 
     Referring again to FIG. 8, the bottle 10 is formed at the base of its neck 64 with a circumambient ridge 90 defining a shoulder 94. When the cap 70 is threadedly applied to the neck 64 of the container, the lower free edge 96 of the generally cylindrical cap wall abuts against and establishes a fluid-tight seal with the shoulder 94 to establish an air-tight chamber between the exposed surface of the applicator ball 34 and the interior of the closure cap 70. The effect is to prevent evaporation of fluid from and deposition of solids on the exposed surface of the ball 34 during periods of non-use of the applicator. 
     The foregoing invention has been described with reference to a preferred embodiment, and numerous equivalents thereof can be made without departing from the spirit and scope of the invention as defined in the following claims.