Tubular construction elements assembled by interlocking parts

Claim 1

A joint construction for joining first and second tubular members eacH having opposed parallel planar side faces comprising: a pair of gripping arms rigidly fixed to and projecting from said opposed sides at one end of said first tubular member, said arms facing each other in spaced parallel relation; the free ends of said arms being turned inwardly toward one another and being formed to define keying hooks; said spaced arms receiving the second tubular member therebetween with one of its planar faces abutting the end of said first tubular member, between said arms; a keying member having opposed lateral edges thereof with keying surfaces formed thereon and mating with the keying hooks of said arms and so formed that movement thereof in one direction parallel to said second tubular member causes said keying member to engage the other side face of said second tubular member and to clamp said second tubular member against the said end of said first tubular member; each keying hook being defined by a recess located near the free end of a gripping arm, inwardly thereof, said recess being in the form of a female half-dovetail; the female half-dovetail of each keying hook being configured to have a slight slope with respect to the second tubular member whereby to wedge said keying member against said second tubular member; the keying member cooperating with the hooks is an element having parallel lateral edges notched in the form of a male half-dovetail slidably fitted into the female half-dovetails of the hooks; the male half-dovetails of the keying member having a slope corresponding to the slope of the hooks; the face of said keying member which bears against the surface of said second tubular member having chamfered end portions and a flat intermediate portion making surface contact with said other side face of said second tubular member.