Plastic container and blank

Claim 1

AN UNSCORED CONTAINER BLANK INTEGRALLY FORMED OF SEMI-RIGID SYNTHETIC PLASTIC SHEET MATERIAL AND INCLUDING A BODY PORTION ADAPTED TO BE COLD-FOLDED INTO FOUR WALL PANELS DEFINING A CONTAINER BODY OF RECTANGULAR CONFIGURATION AND A SIDE-LOCKING FLAP ALONG ONE OUTER SIDE THEREOF, SAID BLANK HAVING A LOCKING TAB ON SAID ONE OUTER SIDE AND A COOPERATING LOCKING INCISION ADJACENT THE OTHER OUTER SIDE THEREOF FOR INTERENGAGEMENT UPON FOLDING OF THE BLANK INTO THE RECTANGULAR BODY CONFIGURATION, SAID BLANK BEING INCISED ALONG ONE EDGE AT THE LINES OF INTENDED FOLD FOR THE WALL PANELS OF THE BODY TO PROVIDE A BOTTOM END WALL FLAP, A PAIR OF DUST FLAPS AND AN ENDLOCKING FLAP AND ADAPTED TO PROVIDE A CLOSURE FOR ONE END OF THE CONTAINER, SAID END-LOCKING FLAP AND END-WALL FLAP BEING SPACED APART BY A DUST FLAP AND ONE OF SAID LOCKING FLAP AND END-WALL FLAP EXTENDING FROM THE PORTION OF THE BLANK ADJACENT SAID LOCKING FLAP OF THE BODY PORTION, ONE OF SAID LOCKING FLAP AND END WALL FLAP HAVING A LOCKING INCISION THEREIN AND THE OTHER OF SAID LOCKING FLAP AND END WALL FLAP HAVING A LOCKING TAB THEREON ENGAGEABLE IN SAID INCISION TO PROVIDE A FIRM CLOSURE, SAID BLANK BEING INCISIED ALONG THE OTHER EDGE THEREOF AT THE LINES OF INTENDED FOLD FOR THE SAID WALL PANELS TO PROVIDE FLAPS ADAPTED TO BE FOLDED INTO A CLOSURE FOR THE OTHER END OF SAID BODY, AT LEAST ONE OF SAID LOCKING INCISION BEING COMPRISED OF A PAIR OF SPACED CURVILINEAR SLITS AND A SLIT EXTENDING TRANSVERSELY THEREOF AND INTERSECTING SAID CURVILINEAR SLITS INTERMEDIATE THEIR LENGTH TO PROVIDE A PAIR OF HINGED FLAPS, THE SPACING BETWEEN SAID CURVILINEAR SLITS VARYING ALONG THE LENGTH THEREOF, THE COOPERATING LOCKING TAB BEING OF GENERALLY DOVETAILED CONFIGURATION WITH ITS FREE END BEING OF GREATER WIDTH THAN THE SPACING BETWEEN SAID CURVILINEAR SLITS AT THEIR POINT OF WIDEST DIVERGENCE AND WITH ITS SIDES TAPERING TO A ROOT PORTION OF LESSER WIDTH THAN THE SPACING BETWEEN THE CURVILINEAR SLITS AT THEIR POINT OF GREATEST DIVERGENCE, SAID ONE TAB BEING ADAPTED TO EXTEND INWARDLY OF SAID ONE LOCKING INCISION WHEREBY SAID TAB WILL OVERLIE THE HINGED FLAP ADJACENT THE EDGE OF THE UNDERLYING PANEL AND THE OTHER OF THE HINGED FLAPS DEFINED BY SAID INCISION WILL OVERLIE SAID TAB AND SAID HINGED FLAPS WILL RESILIENTLY BEAR AGAINST THE SURFACES OF SAID ONE TAB TO PROVIDE FIRM ENGAGEMENT.