METHOD AND DEVICE FOR BENDING BENT RECTANGULAR TUBE AND RECTANGULAR TUBE

摘要

PURPOSE: To prevent the cracking caused at tension side bent face and the wrinkle caused at compression side bent face and provide a bent rectangular tube excellent in strength. ;CONSTITUTION: In a bent rectangular tube P, a recessed part 20 is formed so that at a compression side bent face Pa, a curvature in the longitudinal directions is larger at a center part 21 than at both corner parts 22. Also, a recessed part 24 is formed so that a curvature in the longitudinal direction is smaller at a center part 25 than at both corner parts 26. In this case, the sides 23, 27 formed at recessed parts 20, 24 oppose against the bending force applied to the bending direction of the bent rectangular tube P with working together with both horizontal side faces Pc, the strength against the bending force applied in the bending direction becomes stronger.;COPYRIGHT: (C)1995,JPO