Torsion resistant grooved joint

Claim 1

A torque tube assembly wherein the torsional strength of the end connection exceeds the torsional strength of the tube comprising a pair of end members interconnected by a tubular member, each of said end members having a male extension extending into said tubular member, said male members each having a plurality of axial grooves spaced equidistant circumferentially around said male member with shoulders at the opposite axial ends of said grooves, the inner wall of said tubular member resting on said shoulders, end portions of said tubular member intermediate said shoulders being recessed into said grooves and forming a torque transmitting inteconnection therebetween, each of said axial grooves being comprised of a plurality of straight side walls and a bottom member intersecting said side walls, each of said side walls being equally angularly sloped with respect to a vertically disposed plane normal to a horizontally disposed plane passing through intersections of said side walls and an outer surface of said end members, said intersections of said side walls with said outer surface and said bottom member each having a radius, the axial length of said grooves between said shoulders being greater than the circumferential width of said grooves, the number of grooves in the end member divided by the outer diameter of the end member being equal to or less than 2.1 divided by the groove width, the depth of each groove, as measured substantially vertically at the groove edge, divided by the groove width, measured at the bottom of the groove, being equal to or less than 2, and the angular slope of each of the groove side walls being not substantially less than 5° and not substantially more than 60° with said side walls sloping away from said bottom member of the recess, whereby the angle of slope of said groove side walls is selected in accordance with the wall thickness of said tubular member.