Constructional elements

Claim 1

A longitudinally extending metallic constructional element of transverse L-shaped configuration having a first flange and a second flange with said flanges disposed angularly to one another and each of said flanges having a common longitudinally extending edge and a free longitudinally extending edge, said first flange having a single longitudinally extending row of holes consisting of a series of first elongated holes spaced from each other with the major axis of said holes extending substantially perpendicularly to the longitudinal direction of said flanges, a plurality of second elongated holes with the major axis of said second elongated holes extending in parallel relationship with the longitudinal edges of said flanges, and a plurality of first round holes having the line through the centers thereof coinciding with the major axis of said second elongated holes, in the row of holes in said first flange said first and second elongated holes and said first round holes are arranged in series so that every other hole in the row is one of said first elongated holes and said second elongated holes and said first round holes alternating between said first elongated holes so that each said first elongated hole has one said second elongated hole on one side and one said first round hole on the other side thereof, the center line along the minor axis of said first elongated holes is parallel to and offset from the center line along the major axis of said second elongated holes and the center line of said first round holes, the pitch distance between the centers of the holes in the row in said first flange is the same for each pair of adjacent holes, the distance between the center line of said first round holes in the longitudinal direction of said first flange and the common longitudinal edge of said flanges is approximately equal to one and a half times the thickness of said first flange plus the pitch distance of the holes in said first flange, the distance between the adjacent outer edges of said first elongated holes and said second elongated holes in said row on said first flange is less than the distance between the adjacent outer edges of said first elongated holes and said first round holes, said second flange is wider than said first flange and has three spaced rows of holes extending longitudinally of said second flange, the inner row of said second flange adjacent to the common longitudinally extending edge of said flanges consisting of a plurality of third elongated holes equally spaced from and similar to each other and with the major axis of said third elongated holes extending in the longitudinal direction of said flanges, the middle row of said second flange consisting of alternate fourth elongated holes and second round holes with the major axis of said fourth elongated holes extending perpendicularly to the longitudinal edges of said flanges and the minor axis of said holes and the centers of said second round holes located on a line in parallel relationship with the major axis of said third elongated holes, the outer row of said second flange consisting of a plurality of sets of holes, each said set of holes comprising two fifth elongated holes with the major axis thereof extending in paRallel relationship with the longitudinal edges of said flanges and having therebetween a sixth elongated hole with the major axis thereof extending perpendicularly to the major axis of said fifth elongated holes, said third elongated holes each having a length substantially more than twice the length of one of said fifth elongated holes, the distance between the center line of the major axis of said third elongated holes of said inner row and the common edge of said flanges is equal to the distance between the center line of said first round holes along said first flange and the common edges of said flanges, the center lines along the major axis of said sixth elongated holes in said outer row and of the transversely extending center lines of said second round holes in said middle row and of the transversely extending center lines of said first round holes in the row in said first flange being coincident, the distance between the outer edges of two adjacent said fifth elongated holes in said outer row is less than the distance between the outer edges of two adjacent said third elongated holes in said inner row, and the distance between the outer edges of two adjacent said fifth elongated holes is greater than the pitch interval of said holes in said first flange.