公开(公告)号：EP0131429A3

公开(公告)日：1985-07-10

申请号：EP84304580

申请日：1984-07-04

申请人： NATIONAL RESEARCH DEVELOPMENT CORPORATION

发明人： Ibrahim, Ibrahim Nairouz ,  Sansome, Dennis Hugh

IPC分类号： B21D09/04

CPC分类号： B21D9/073 ,  Y10S72/71

摘要： Apparatus for draw-bending metal tubes and other elongated workpieces of hollow section, in which a mandrel, supported on a bar within the tube, bears againstthe inner wall of the tube in the region of the bend and helps to prevent the tube section from collapsing or distorting. Vibration transducers (26) are attached to the barto set up a standing wave of resonant vibration within the mandrel (19) and bar (14) which has the effect of reducing friction between the mandrel and the tube. A special coupling device (25) may be used to attach the transducers to the bar and may also serve to connect the bar to the fixed structure of the apparatus, and the invention includes the complete apparatus when tuned so as to generate a displacement antinode of vibration at the mandrel tip, a displacement node at the point of attachment of the coupling device to the structure, and agenerally so as to minimise waste of the vibratory energy.