PURPOSE: To manufacture a wide corrugated plate at a low cost by working while gradually shifting the part to be corrugated from the end part in the width direction of a long plate to the center part and suppressing the reduction of width at the time of corrugation, in the case of forming a corrugation on a long plate.
CONSTITUTION: In forming corrugation in the width direction of a long plate or a band material, a corrugation work is performed by gradually shifting the long plate or band material from the end part in the width direction to the center part. Thus, the restraint against tension in width direction (width shrinkage stress) generated inside the plate during the corrugation work is effectively enhanced. Between a forming tool 6 and the raw material 7, not only the friction R but also the restraint R', by which the pull-in of the corrugated shape on the side of the stepped part formed in the preceding stage is suppressed, is applied as a restraint against the width shrinkage stress at the time of corrugation work near the center of the width. If the corrugation on the end part is sufficiently formed in the preceding stage by this restraint R', the stress may be increased as much as the deformation resisting value of the plate, and the maximum effect as the restraint is expected.
OGAWA SHIGERU
TAKAMACHI YASUYUKI
