Field of the invention

[001] This invention relates to a roll-on applicator ball.

[002] In particular the invention relates to an applicator ball fora roll-on cosmetics applicator.

Background to the invention

[003] All around the world roll-on balls are widely used in applicators that dispense deodorant, perfume, cosmetics, essential oils, personal care products, pharmaceuticals and much more.

[004] Currently such applicator balls are manufactured as injection moulded half shells that are adhesively bonded together along plane mating surfaces which are un-formed and are simply butt-jointed with adhesive. Post-processing is required to obtain the required ball sphericity in that the ball, after adhesive bonding, must be reground to spherical to remove the adhesive flashing that leaks from the butt joint during adhesive bonding.

[005] It is an object of this invention to provide a watertight roll-on applicator ball that requires no post-processing (such as regrinding) but is ready, as is, for installation in a ball applicator. Summary of the invention

[006] According to one aspect of the invention, a roll-on applicator ball comprises upper and lower half shells configured for assembly, by mating of the half shells to one another along complementally shaped mating surfaces, to define a spherical ball: the upper half shell having a tongue formation formed in its mating surface and the lower half shell having a complementally shaped groove formation formed in its mating surface; and the tongue and groove formations including complemental snap-fit formations by means of which the upper half shell may be snap-fitted to the lower half shell during assembly of the ball.

[007] The tongue and groove formations are preferably configured to maintain ball sphericity and watertight engagement between the half shells, such that upon the half shells being snap-fitted together, the ball is ready for installation in a ball applicator, without any post-processing (such as regrinding) being required.

[008] The snap-fit formations may conveniently comprise an undercut barb formation formed on the tongue formation of the upper half shell and a complementally shaped undercut formed in the groove formation in the lower half shell, the undercut barb formation extending peripherally inwardly about the edge of the tongue formation and the undercut in the lower half shell groove formation extending peripherally outwardly, the undercut groove formation being shaped complementally to the undercut barb formation and dimensioned to accept and engage the barb formation when the upper half shell is snap-fitted to the lower half shell.

[009] The groove formation in the lower half shell preferably comprises an open groove bounded by spaced apart outwardly and inwardly facing walls, the outwardly facing wall having a shoulder formation located at the entrance to the groove, the shoulder formation extending in a smooth curve from the half shell mating surface into the groove and the underside of the shoulder formation being undercut complementally to the undercut barb formation and dimensioned to accept and engage the barb formation when the upper half shell is snap-fitted to the lower half shell.

[0010] The undercut barb formation and preferably also the tongue formation of the upper half shell are sufficiently resiliently deformable for the barb formation to deform and slide over the rounded shoulder of the undercut groove formation in the lower half shell when, during assembly of the ball, the upper half shell tongue formation is pressed into the lower half shell groove formation and to snap back resiliently to engage the undercut formed on the underside of the shoulder formation when the tongue formation is fully engaged in the groove formation.

[0011] The tongue and groove formations may be tapered, the undercut formations being dimensioned to draw the tapered tongue and groove formations into an interference fit between the tongue and groove formations upon engagement of the undercut formations with one another, thereby ensuring a watertight engagement between the upper and lower half shells.

[0012] In the preferred form of the invention, the inwardly facing wall of the groove formation formed in the lower half shell is preferably extended above the surface of the lower half shell mating surface, to define a tongue formation extending from the lower half shell mating surface, the upper half shell being formed with a complementally shaped groove formation configured to accept the lower half shell tongue formation when the upper half shell is snap-fitted to the lower half shell.

[0013] The groove formations may be deeply grooved and the tongue formations may be complementally oversized to extend fully and deeply into the groove formations, thereby to define a tortuous path sufficient to overcome substantial fluid capillary pressure.

[0014] Once the upper half shell and lower half shell have been snap-fitted together to form the assembled roll-on ball, the tongue and groove formations define a watertight joint extending about a median line of the ball.

[0015] The assembled ball may have a thickened inner wall on either side of the watertight joint line to accommodate the deep tongue and groove formations. The thickened inner wall may define an inwardly enlarged clip engagement zone extending about the equator of the ball to assist in ensuring and maintaining ball sphericity.

[0016] The upper and lower half shells may be formed by injection moulding of a thermoplastic material, preferably selected from polypropylene, PET (polyethylene terephthalate), or HDPE (high density polyethylene).

[0017] In the preferred form of the invention, the thermoplastic material is formulated for the material, of the barb and tongue formations in particular, to be resiliently deformable only above a predetermined high temperature, preferably predetermined to be at or near the temperature of the material at the time of ejection of the moulded half shells from the mould and for the material to be substantially non-deformable below a predetermined low temperature, preferably predetermined to be at or near the ambient temperature of the operating environment of the half shells and the assembled half shells in particular.

[0018] The assembled ball may be directly installed within an applicator to dispense deodorant, perfume, cosmetics, essential oils, personal care products, pharmaceuticals or the like.

[0019] The invention includes a container including a roll-on applicator substantially as described above.

Brief Description of the drawings

[0020] The invention will be further described with reference to the accompanying drawings in which:

Figure 1 is a plan view of a roll-on applicator ball according to one aspect of the invention;

Figure 2 is a cross-sectional view of section A-A of the roll-on applicator ball as shown in Figure 1 ;

Figure 3 is a plan view of an upper half shell of the roll-on applicator ball;

Figure 4 is a cross-sectional view of section A-A of the upper half shell as shown in Figure 3;

Figure 5 is a plan view of a lower half shell of the roll-on applicator ball;

Figure 6 is a cross-sectional view of section A-A of the lower half shell as shown in Figure 5;

Figure 7 is a detailed view of Detail B in Figure 2, showing an interference fit of a tongue and groove formation of the upper and lower half shells;

Figure 8 is a detailed view of Detail B in Figure 4, showing the tongue formation of the upper half shell;

Figure 9 is a detailed view of Detail B in Figure 6, showing the groove formation of the lower half shell; and

Figure 10 is a detailed view of Detail C in Figure 6, showing the groove formation of the lower half shell.

Description of embodiments of the invention

[0021] In the Figures 1 and 2 reference numeral 10 refers to a roll-on applicator ball suitable for direct installation within an applicator that disperses either deodorant, perfume, cosmetics, essential oils, personal care products, pharmaceuticals and the like once the ball 10 has been assembled without requiring any post-processing (such as regrinding).

[0022] The roll-on applicator ball 10 comprises an upper half shell 12 and a lower half shell 16 that are snap-fit together to form the ball 10.

[0023] The terms “upper”, “lower” are not intended to refer to absolute orientation of the ball 10. These terms are used figuratively with reference to the applicator ball 10 as drawn (in the drawings). In the event that the ball 10 is rotated in use, the orientation implied by these terms must be adjusted accordingly.

[0024] The upper half shell 12, in Figures 3 and 4, has a tongue formation 14 in its mating surface 12.1 , which includes a complemental snap-fit formation 14.1 (shown in Figure 8) by means of which the upper half shell 12 is snap-fitted to the lower half shell 16 during assembly of the ball 10.

[0025] The lower half shell 16, in Figures 5 and 6, has a groove formation 18 in its mating surface 16.1 , which is complementary to the tongue formation 14 in that it includes a complemental snap-fit formation 18.1 .

[0026] The tongue 14 and groove formations 18 are configured to maintain ball sphericity and watertight engagement between the half shells 12, 16, once the ball 10 is assembled.

[0027] The snap-fit formations 14.1 , 18.1 conveniently comprise an undercut barb formation formed on the tongue formation 14 of the upper half shell 12 and a complementary shaped undercut formed in the groove formation 18 in the lower half shell 16. The undercut barb formation 14.1 extends peripherally inwardly about the edge of the tongue formation 14 and the undercut 18.1 in the lower half shell groove formation 18 extends peripherally outwardly (shown in Figures 9 and 10).

[0028] In this specification, the term "inwardly" implies towards the interior of the ball 10 and the term "outwardly" implies towards the exterior of the ball 10.

[0029] As best shown in Figure 7, the groove formation 18 in the lower half shell 16 comprises an open groove bounded by spaced apart outwardly 18.2 and inwardly 18.3 facing walls. The outwardly facing wall 18.2 has a shoulder formation 18.4 located at the entrance to the groove 18, the shoulder formation 18.4 extending in a smooth curve from the half shell mating surface 16.1 into the groove 18 and the underside of the shoulder formation being undercut 18.1 complementally to the undercut barb formation 14.1 and dimensioned to accept and engage the barb formation 14.1 when the upper half shell 12 is snap-fitted to the lower half shell 16. [0030] The undercut barb formation 14.1 and the tongue formation 14 of the upper half shell are sufficiently resiliently deformable for the barb formation 14.1 to deform and slide over the rounded shoulder 18.4 of the undercut groove formation 18.1 in the lower half shell 16 when, during assembly of the ball 10, the upper half shell tongue formation 14 is pressed into the lower half shell groove formation 18 and to snap back resiliently to engage the undercut 18.1 formed on the underside of the shoulder formation 18.4 when the tongue formation 14 is fully engaged in the groove formation 18.

[0031] In this specification, the term “sufficiently resiliently deformable” must be given a special meaning in that the material of the half shells 12, 16, and the material of the barb and tongue formations in particular, need not be resiliently deformable at all times or in all circumstances.

[0032] In preferred embodiments of the invention, the thermoplastic material used in the fabrication of the half shells 12, 16 is selected and formulated for the material to be resiliently deformable only above a predetermined high temperature and substantially non-deformable below a predetermined low-temperature. The predetermined high temperature is selected to be at or near the temperature of the material at the time of ejection of the moulded half shells 12, 16 from the mould and for the material to be substantially non-deformable below a predetermined low temperature, which is preferably predetermined to be at or near the ambient temperature of the operating environment of the half shells and the assembled half shells in particular.

[0033] This will require assembly of the half shells 12, 16 immediately upon ejection of the half shell moulded parts from the mould, while the material temperature is at or near the predetermined high temperature, which is sufficiently high to ensure that the half shells 12, 16 and the barb and tongue formations are sufficiently resiliently deformable for the barb and tongue formations to deform and slide over one another to permit snap-fit assembly of the ball 10.

[0034] The material deformability is lost once the half shells 12, 16 have cooled, thereby ensuring permanent engagement of the snap-fitted together half shells 12, [0035] The tongue 14 and groove 18 formations are tapered, the undercut formation 14.1 , 18.1 being dimensioned to draw the tapered tongue 14 and groove formations 18 into an interference fit between the formations upon engagement of the undercut formations 14.1 , 18.1 with one another. This ensures a watertight engagement between the upper 12 and lower half shells 16.

[0036] In the preferred form of the invention, the inwardly facing wall 18.3 of the groove formation 18 formed in the lower half shell 16 is preferably extended above the surface of the lower half shell mating surface 16.1 , to define a tongue formation 18.5 extending from the lower half shell mating surface 16.1 , the upper half shell 12 being formed with a complementary shaped groove formation 14.2 configured to accept the lower half shell tongue formation 18.5 when the upper half shell 12 is snap-fitted to the lower half shell 16.

[0037] The groove formations 18, 14.2 are deeply grooved and the tongue formations 14, 18.5 are complementally oversized to extend fully and deeply into the groove formations 18, 14.2, thereby to define a tortuous path 22 sufficient to overcome substantial fluid capillary pressure.

[0038] Once the upper half shell 12 and lower half shell 16 have been snap-fit together to form the assembled roll-on ball 10, the tongue 14 and groove formations 18 define a watertight joint 20 extending about a median line of the ball 10.

[0039] The assembled roll-on applicator ball 10 has a thickened inner wall 24 on either side of the watertight joint line 20 to accommodate the deep tongue 14, 18.5 and groove formations 18, 14.2. The thickened inner wall 24 defines an inwardly enlarged clip engagement zone extending about the equator of the ball 10 to assist in ensuring and maintaining ball sphericity.

[0040] The upper 12 and lower half shells 16 are formed by injection moulding from thermoplastics material, preferably selected from polypropylene, PET (polyethylene terephthalate), or HDPE (high density polyethylene).