US Patent 7090427 Bar connecting clamp

A clamp for connecting together a set of structural bars having a body defining at least one pair of prismatic guides for positioning one of the bars within the clamp and a locking mechanism for securing the bars inside the guides. The body is defined by four sheet metal plates arranged parallel and facing each other in pairs of two, each pair of two arranged perpendicular to the other such that each pair is connected to the other collectively along four parallel edges of the body. The prismatic guides are each defined by a pair of aligned seats formed along respective sides of each pair of facing plates.