Thin-walled stackable container lid

Claim 1

A thin-walled stackable container lid (10) constituted of hot-molded foil-thin thermoplastic substance, said lid (10) having a circular peripheral sealing rib (9) of somewhat U-shaped cross section for introduction into an opening of a container, the outer leg portion (13) of the sealing rib (9) transitioning with a circular flange (29) and the inner leg portion (14) of the sealing rib (9) transitioning with the actual lid body (11), said two leg portions (13, 14) forming an annular groove (12) which is open at the top of the lid (10) and which tapers to a smaller width towards the top, the annular bottom wall (15) of the sealing rib (9) having, molded in it, stacking ring means (19, 20) which project downwardly and are receivable in the opening slot (16) of the annular groove (12) of an identical underlying lid (10), said sealing rib (9) having annular stacking seating surfaces (17, 18) which are coextensive with said stacking ring means (19, 20), characterized in that there is provided on the circular flange (29) transitioning from the sealing rib (9) an outer peripheral transition rim (36) and a snap rim (30) connected to said transition rim (36) and extending essentially axially downward therefrom, said snap rim (30) having bevelled detention elements (33) for camming engagement with a transition rim (36) of an identical underlying lid (10), thereby to lift the stacking ring means (19, 20) of the overlying lid (10) out of the annular groove (16) of the underlying lid (10) in response to transaxial forces applied to the underlying lid (10).