Cover, A Container Assembly Including The Cover, A Molding Device For Molding The Cover And A Method For Manufacturing The Cover

Abstract

A cover for covering an opening of a container for a food stuff includes a substantially flat cover body including at least one aperture and at least one substantially flat flap. The at least one flap including a linear proximal end configured to connect with the cover body and allow the at least one flap to rotate with respect to the cover body. A lower surface of the at least one flap includes a protrusion configured to close the at least one aperture when the at least one flap is at a first position in which the at least one flap is in parallel with the cover body. The cover body and the at least one flap are integrally formed by a co-injection molding. The container and cover are suitable for heating a food stuff in a microwave.

1 . A cover for covering an opening of a container for heating a food stuff, the cover comprising:
 an elevated peripheral portion defining an outer contour of the cover and configured to engage with an edge of the container defining its opening;   an elevated area surrounded by and positioned apart from the elevated peripheral portion, the elevated area being lower than the peripheral portion;   a plurality of air vent ports defined in the elevated area;   at least one flap including a proximal end integrally connected to an edge of the elevated area, the at least one flap configured to rotate around the proximal end;   at least one protrusion extending from a first surface of the at least one flap and configured to plug at least one of the plurality of air vent ports when the flap reaches a first position where the at least one flap is received in a concave area defined in the elevated area; and   a groove defined at the proximal end in the first surface of the at least one flap wherein a second surface opposite to the first surface at the proximal end is straight when the flap stands upright to the concave area.   
     
     
         2 . The cover in  claim 1 , wherein the second surface of the at least one flap does not protrude from a surface of the elevated area when the at least one flap reaches the first position. 
     
     
         3 . The cover in  claim 1 , wherein the cover is not deformed under a thermal condition less than 140 degrees centigrade. 
     
     
         4 . The cover in  claim 1 , wherein the cover is molded from a high crystallinity polypropylene. 
     
     
         5 . The cover in  claim 1  further comprising a tab protruding outwardly from a peripheral edge of the cover. 
     
     
         6 . The cover in  claim 1 , wherein the proximal end of the at least one flap is located farther away from a center of the cover than a distal end of the flap. 
     
     
         7 . The cover in  claim 1 , wherein:
 the elevated area includes a concave portion adjacent to the concave area; and   a distal end of the flap partly covers across the concave portion when the at least one flap reaches the first position.   
     
     
         8 . The cover in  claim 1 , further comprising an intermediate area connecting the elevated peripheral portion and the elevated area, the intermediate area being lower than the elevated area and surrounding the elevated area. 
     
     
         9 . The cover in  claim 1 , wherein the at least one flap is configured to rotate upwardly from the first position responsive to an inner pressure of the container exceeding a predetermined pressure when the cover is installed on the container. 
     
     
         10 . The cover in  claim 9 , wherein the predetermined pressure is determined by a friction force between the at least one protrusion and the at least one of the plurality of air vent ports. 
     
     
         11 . A container assembly for heating a food stuff comprising a container including a bottom and at least one side wall surrounding the bottom, and a cover for covering an opening of the container comprising:
 an elevated peripheral portion defining an outer contour of the cover and configured to engage with an edge of the container defining its opening;   an elevated area surrounded by and positioned apart from the elevated peripheral portion, the elevated area being lower than the peripheral portion;   a plurality of air vent ports defined in the elevated area of the cover;   at least one flap including a proximal end integrally connected to an edge of the elevated area, the at least one flap configured to rotate around the proximal end;   at least one protrusion extending from a first surface of the at least one flap and configured to plug at least one of the plurality of air vent ports when the flap reaches a first position where the at least one flap is received in a concave area defined in the elevated area; and   a groove defined at the proximal end in the first surface of the at least one flap wherein a second surface opposite to the first surface at the proximal end is straight when the flap stands upright to the concave area.   
     
     
         12 . The container assembly in  claim 11 , wherein the second surface of the at least one flap does not protrude from a surface of the elevated area when the at least one flap reaches the first position. 
     
     
         13 . The container assembly in  claim 11 , wherein the cover is not deformed under a thermal condition less than  140  degrees centigrade. 
     
     
         14 . The container assembly in  claim 11 , wherein the cover is molded from a high crystallinity polypropylene. 
     
     
         15 . The container assembly in  claim 11 , further comprising a tab protruding outwardly from a peripheral edge of the cover. 
     
     
         16 . The container assembly in  claim 11 , wherein the proximal end of the at least one flap is located farther away from a center of the cover than a distal end of the flap. 
     
     
         17 . The container assembly in  claim 11 , wherein:
 the elevated area includes a concave portion adjacent to the concave area; and   a distal end of the at least one flap partly covers across the concave portion when the at least one flap reaches the first position.   
     
     
         18 . The container assembly in  claim 11 , wherein the cover includes an intermediate area connecting the elevated peripheral portion and the elevated area, the intermediate area being lower than the elevated area and surrounding the elevated area. 
     
     
         19 . The container assembly in  claim 11 , wherein the at least one flap is configured to rotate upwardly from the first position when an inner pressure of the container assembly exceeds a predetermined pressure. 
     
     
         20 . The container assembly in  claim 19 , wherein the predetermined pressure is determined by a friction force between the at least one protrusion and the at least one of the plurality of air vent ports.