Corner lock for paperboard containers

Claim 1

In a container structure of cardboard or similar material, said structure comprising an integral floor panel and a plurality of wall panels, with at least a pair of said wall panels being disposable substantially normal to said floor panel and to each other to form a corner for each container, said wall panels each having a side edge and a bottom edge, said bottom edges being adjacent said floor panel periphery, the improvement comprising an integral locking means for locking said disposed pair of wall panels to each other to form said corner, one of said pair of wall panels having a substantially horizontal slit extending therethrough, said slit having an end adjacent said corner, said other wall panel of said pair having a flap extending from said side edge of said other wall panel, said flap having a portion only being insertable in an entry position thereof into said wall panel slit into a locking position therein for locking said disposed pair of wall panels to each other to form said corner and Having a pivot-axis in substantial coincidence with said slit when in said locking position, said flap portion thereof extending substantially downward after being inserted in said slit and having a base and a locking edge substantially facing the base of said flap, said locking edge substantially facing said corner in said locking position and extending at one end to one extremity of said pivot-axis and forming at said locking edge one end an acute angle with a straight line drawn from said locking edge one end to the juncture of the bottom edges of said pair of wall panels, said flap having an outer edge portion spaced from said locking edge at one extremity and substantially intersecting said locking edge to form a point at another extremity, said point being initially insertable through said slit during said flap insertion, said lock edge one end substantially abutting said slit end when in said locking position, said flap being bendable about said pivot-axis in a direction toward said slit for deflecting said locking edge from said acute angle toward at least substantially a right angle with respect to said straight line to widen said acute angle in the direction toward said slit for providing said entry position and in an opposite direction to substantially reform said acute angle from said widened angle for providing said locking position substantially after completion of insertion of said flap through said slit, said pivot-axis being at an angle of less than 180* with respect to said straight line on the side of said locking edge to cause said acute angle widening for enabling provision of said entry position and for enabling provision of said locking position upon said acute angle substantial reformation, said flap only being removable after said completion of insertion upon a reforming of said widened angle, whereby said completion of said insertion of said flap through said slit locks said flap in said locking position for forming said corner from said locked wall panel pair.