Child-proof overcap for an aerosol can

Claim 1

A child-proof overcap for an aerosol can having a cylindrical body, an upper end joined to said can body by an annular seam, a central discharge valve in said upper end and an annular valve retaining seam concentric with said valve, said overcap comprising in combination, an inverted cup-shaped cover enclosing said valve and having a top, an inner annular retainer skirt and an annular outer skirt, a separate annular locking element mounted on and closely circumjacent said valve retaining seam and functionally integral with said can, cooperating annularly arranged groups of locking elements on said annular element and on said retainer skirt, one of said groups of locking elements comprising at least two lug threads evenly spaced circumferentially and protruding radially towards the others of said locking elements, each of said lug threads having an angularly and downwardly extending undersurface and an upwardly extending undercut recess at the end of said undersurface, the other of said groups of locking elements comprising a similar number of similarly spaced lugs which protrude radially toward said lug threads and that are engageable with said lug threads and in said recesses upon rotation of said can and said cover relative to each other, means for resiliently biasing one of said groups of locking elements relative to the other of said groups of locking elements in an axial direction for moving said lugs into the recesses in said lug threads for restraining said cover against rotary and axial movements relative to said annular locking element and to said can.