Nesting insulated hot-or-cold food tray

Insulated hot or cold food tray for temporarily storing and transporting food items at temperatures different from ambient temperatures comprising

• an integral dished tray structure of molded material having
• a bottom plate surface (10);
• a surrounding rim (11) formed to incline upwardly with respect to the bottom plate surface;
• and a flange (12) laterally projecting from the rim generally in a plane parallel to said bottom surface (10);
• the angle of inclination of the rim being selected such that cotangent .alpha. is at least 1.5 t/D
• wherein .alpha. equals angle of inclination;
• t equals wall thickness of the foamed plastic material and D equals depth of the tray structure and corresponding to the distance from the top of the flange (12) to the top of the bottom plate surface (10);
• said flange (12) being formed with projection and recess means (13, 14;
• 23, 24) located at regularly distributed spaced intervals around the circumference thereof,
• the projection means have portions which have a dimension which is greater than the dimension of the recess means (14, 24) at equal spacing from the surrounding rim (11),
• inversion of one tray over another and engagement of the projection means of one tray in the recess means of the inverted, opposite tray permitting fitting of said flanges together and locking the projection means of one tray through the recess means of the other to engage the flange of the other tray from the face opposite that facing the first tray to provide an insulated storage and transport carrier to transport food items in the chamber formed by the inverted, engaged trays with the flanges of the trays locked together by overlapping engagement of the respective projection means of one tray behind the flanges of the other tray;
• wherein the projection means of the projection and recess means comprises buttons (23) formed on the flange (22) and projecting from the major plan thereof;
• and the recess means comprises notches (24) formed in the periphery of the rim and shaped to at least in part surround the buttons (23);
• the surface (23') of the button (23) facing the center of the tray being slightly closer to the center of the tray than the surface (24') of the notch closest to the center of the tray the thickness of the material of the button (23) adjacent said surface (23') facing the center of the tray is reduced to permit indentation or undercutting of the button when the button (23) of one tray is engaged in the notch (24) of another tray inverted thereover to result in overlap, or bulging over of the button (23) beneath the flange formed with the notch (24).