Patent ID: 8037595
Filing Date: 2011-10-18
Classification: B21D,B23P,F28D,F28F,Y10T

Abstract:
1. In a hairpin expander machine ( 250 ) for the manufacture of tube and fin heat exchangers ( 10 ), said hairpin expander machine ( 250 ) having (a) a fixture ( 259 ) for holding a heat exchanger assembly, which includes a loose stack of fins ( 12 ′) disposed between top and bottom end plates ( 14 , 16 ) and at least one hairpin tube ( 22 ) laced through the stack of fins ( 12 ′) and the top and bottom end plates ( 14 , 16 ), (b) a first actuator ( 252 ) coupled between said fixture ( 259 ) and at least one rod ( 256 ) so as to forcefully drive said at least one rod ( 256 ) within said at least one hairpin tube ( 22 ) to enlarge the diameter of said at least one hairpin tube ( 22 ), and (c) a second actuator ( 274 ) coupled between said fixture ( 259 ) and a bolster plate ( 272 ) so as to support said at least one hairpin tube ( 22 ) at its bent end ( 23 ) during expansion, the improvement comprising: a base plate ( first and second bridges ( a retaining member ( said retaining member (