Nestable food container having improved closure system

Claim 1

In a nestable container consisting of a base, sidewalls, and a flat peripheral flange having male and female locking members disposed in the flange on substantially opposing edges of the flange, whereby a first said container may be lockingly engaged with a second said container inverted thereover to form a substantially closed composite container, the improvement comprising: the female locking member comprises an open recess within the flange wherein the width of the recess is greater at the rear face of the recess than at the front of the recess, the male locking member comprises a tongue member having a pair of extending tabs, the distance across the face of said tongue member between said tabs being greater than the width across the rear face of said recess, and the flange is provided with lock stabilizer means protecting the male and female members from accidental disengagement when handling forces are exerted on the composite container, said lock stabilizer means comprising protrusions and mating depressions formed integrally in the flat surface of said flange and positioned to closely flank each of the male and female locking members.