Roll-on applicator ball

A roll-on applicator ball comprising 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;
• 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;
• the snap-fit formations comprising 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 opening 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 assembled to the lower half shell;
• the groove formation in the lower half shell comprising 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 assembled to the lower half shell;
• the undercut barb formation and the tongue formation of the upper half shell being 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;
• and
• the half shells and the tongue and groove formations being configured such that upon the half shells being snap-fitted together to assemble the ball, the ball is ready for installation in a ball applicator without post-processing.