Patent ID: 7422247

Claim:
A branch tee fitting comprising: a tubular body portion ( 11 ) having a pair of openings at both ends; and a tubular branch portion ( 12 ) perpendicular to the tubular body portion ( 11 ), the tubular body portion ( 11 ) and the tubular branch portion ( 12 ) being formed in such a manner that one plate ( 1 a ) is bent and along a plane inclusive of the center line of the tubular body portion ( 11 ) and the center line of the tubular branch portion ( 12 ), facing edges of the bent plate ( 1 a ) are joined in superposed relation, angles between the tubular body portion ( 11 ) and the tubular branch portion ( 12 ) being formed with flat portions ( 13 ), respectively, in which corners of the plates ( 1 a ) are superposed to each other, wherein the branch tee fitting includes engaging pawls ( 14 ) for engaging the superposed flat portions ( 13 ), wherein each of the engaging pawls ( 14 ) is formed on one of the superposed flat portions ( 13 ), and constructed so that it is bent over the other of the flat portions ( 13 ) to engage both of the flat portions ( 13 ) wherein each of the flat portions ( 13 ) is formed in a substantially triangular region defined by a base end of the tubular branch portion ( 12 ) and an edge side which is a straight line connecting associated corner points of the tubular body portion ( 11 ) and the tubular branch portion ( 12 ).