Fittings for a truck box enclosure

A fitting structure for attachment to side and end members to enable assembly of an enclosure about a cargo carrying area of a vehicle, said fitting structure comprising,

• a substantially planar insert fitting for attachment to a first member of the enclosure, said fitting being formed entirely of plate stock having an elongate opening, said insert fitting having a leg member defining a first side of said elongate opening, said fitting having multiple apertures for reception of fasteners,
• a socket fitting formed entirely from plate stock and having a base for attachment to a second member of the enclosure, intersecting walls defining an acute included angle and integral with said base and,
• said base formed of two spaced apart substantially equal coplanar portions having a width and length, the portions being connected by a pair of converging walls having a width and length, the length of the walls being less than the length of the portions, the walls form a socket defining an upright socket having a width Y or inserted reception of said leg member, said base defining multiple apertures or the reception of fasteners,
• said intersecting walls of the socket forming an apex, said apex received in said elongate opening in said insert fitting, and
• said leg member being of a width X to substantially occupy the width Y of said upright socket lying in a plane bisecting said apex to restrict undesired horizontal movement between joined side and end members.