Joint for interconnecting panels

A joint between adjacent panels, comprising:

• first and second upstanding panel members having first and second cooperatively bent members, respectively, at adjoining vertical edges thereof,
• said first and second cooperatively bent members being coupled to define a vertically extending, open-ended cavity having a substantially rectangular configuration in horizontal section, predetermined first and second opposite corners of which are formed from the first and second cooperatively bent members, respectively,
• and expandable locking means disposed in said vertically extending cavity,
• said expandable locking means having at least first and second relatively movable plate members defining first and second vertically extending edge portions, respectively, which extend outwardly from opposite sides of said expandable locking means, said first and second edge portions extending along substantially the complete height of said cavity adjacent to the first and second opposite corners of said substantially rectangular configuration,
• said first and second edge portions increasing their spacing upon predetermined substantially vertical movement of one plate member relative to the other, to cause the first and second edges of the plate members to apply a substantially uniform pressure against the first and second opposite corners of the rectangular configuration, over substantially the complete lengths of the first and second opposite corners, to maintain the first and second panel members in assembled relation.