Duct joint assembly

Claim 1

A joint assembly for connecting together at their ends a pair of ducts each consisting of sheet material forming side walls of said ducts, said ducts having congruent polygonal cross sectional configurations, said side walls being planar and joined together longitudinally of said ducts to form corners of said polygonal configuration, said joint assembly conprising: a plurality of joint sections, each of said joint sections being formed to include a pair of generally perpendicularly extending flanges; said flanges each being formed of double walls, with one of said flanges being adapted to engage therebetween one of the side walls to said ducts; said joint sections each being mounted on the ends of said ducts with said one flange of each joint section having engaged between its double walls the end of one of said side walls of said ducts; there being provided one joint section for each of the side walls of each of said ducts; and a plurality of angle plates each including a corner region having a pair of arms extending from said corner region; each of said angle plates being positioned within said joint assembly with each of said arms extending to between the double walls of the other of said flanges of said joint sections; each of said angle plates being arranged so that its arms extend oppositely from said corner region into flanges of adjacent joint sections of one of said ducts; said corner regions of each of said angle plates on one of said ducts being connected with a corner region of one of the angle plates on the other of said ducts, with each arm of each of said angle plates on one duct being brought into generally facing relationship across said joint assembly with an arm of an adjacent angle plate on the other of said ducts; each pair of facing arms thus pressing therebetween one of the double walls of the flanges within which each said arms extend, each pair of arms therefore pressing therebetween two walls, one each from different flanges; each of said arms of each of said angle plates being formed with a curved configuration which extends from said corner region outwardly therefrom to the end of each arm; the curved configuration of said arms being oriented so that each of said pair of facing arms is arranged with the ends of each arm curving toward the end of the facing arm across the joint assembly to provide enhanced joinder pressure at the ends of each pair of arms, said curved configuration of the arms thus operating to form from each pair of facing arms individual pairs of pincers to enhance the joinder pressure by which said joint sections connect together said pair of ducts.