Patent attributes
A method of manufacturing a heat exchanger includes forming elongated holes in two connection walls among a plurality of connection walls to be laminated, and forming paired notches on a claw forming portion of the remaining connection wall facing the elongated holes. A longitudinally intermediate portion of the claw forming portion is pressed toward the other end to break the claw forming portion at the longitudinal center and bend the claw forming portion at the notches to thereby form two claws forming pieces and form bent portions at the distal ends of the claws forming pieces. The claws forming pieces are bent at the notches to form claws. Distal end portions of the claws are bent outward to form fold-back portions, which are engaged with the outer surface of the connection wall at the other end, whereby all the connection walls are provisionally fixed together.
