To provide a mandrel for a tube bender suffering a reduced change in a cross sectional shape in bending.
The mandrel for a tube bender in which mandrel pieces having an outer peripheral face of a prescribed width corresponding to a tube inner peripheral face to be bent, a bearing arranged to one end side in the axial direction and an object to be supported by a bearing arranged to the other end in the axial direction are engaged with each other by an adjacent bearing and object to be supported and the mandrel pieces are connected in a freely undulating way is inserted into the inside of a bending part of the tube so as to prevent a cross section of the tube from deforming. One end side part of the outer peripheral face of the mandrel piece in the axial direction is made to a spherical face located at a prescribed radius from an undulation center of the bearing and the object to be supported engaging each other, and the other end of the mandrel piece in the axial direction has a recessed part into which one end side part of the spherical face of the adjacent mandrel piece can enter. The tube bender mandrel has an effect to increase the dimensional precision of a tube to be bent.
OSHIMA HIROYOSHI
TANOUE TAKESHI
TAIHO SEIKI CO LTD
FUJI WORLD KK