Joint construction for connecting together two frame members

Claim 1

A joint construction for connecting together two frame members wherein: a. a first of said frame members has opposite side limbs connected by a base so that the side limbs and base collectively define a trough-like shape, b. said first frame member base having formed therein a re-entrant trough-shaped recess which extends longitudinally of the first frame member, c. said recess including a base having a plurality of slots spaced longitudinally along the recess thereof, and contact elements disposed at the margins of the slots and projecting from the recess base in a direction away from a mouth of a re-entrant trough-shaped recess, d. the second of said frame members being of trough-shape and having a limb which comprises a plurality of hook-shaped tongue elements spaced longitudinally from one another, e. said slots in the base of the re-entrant trough-shaped recess have mutually-inclined lateral margins so that each slot is wider at one end than at the other end thereof, said contact elements are similarly mutually inclined, f. at least one of the tongue elements of the second frame member is inclined to a longitudinal axis of the second frame member, g. the second trough-shaped frame member having an effective size to embrace the outer surface of one side limb, a part of the base of the first frame member and one side of the re-entrant trough-shaped recess formed therein, h. said tongue elements are engaged in said slots with one of the tongue elements being in face-to-face wedging engagement with a respective one of said contact elements, i. said wedging engagement being effective to hold the second frame member firmly in contact with the outer surface of said one side limb of the first frame member and to support the second frame member against downward movement relative to the first frame member.