Method of and apparatus for folding annular band.

摘要

For folding an annular resilient band about a circumferential fold line, the band is first wrapped on a generally cylindrical, radially collapsible drum structure (10) having a cylindrical external contour about the center axis of the drum and an annular zone (Z) radially inward of the contour with an inflatable annular first bladder (144; 144') positioned in such a manner as to have a folded-over axial end portion (144a) axially protruding into the aforesaid annular zone (Z) and with an inflatable annular second bladder (146; 146') positioned radially inwardly of the first bladder (144; 144') and in such a manner that the first and second bladders (144, 146) have axial portions overlapping each other, whereupon the first bladder (144; 144') is inflated to a medium expanded state so that an axial end portion of the band on the drum structure (10) is contacted by the bladder (144; 144') and displaced radially outwardly and thereafter the first bladder (144; 144') is moved axially away from the drum structure (10) for forming an annular gap between the first bladder (144, 144') and the axial end portion of the band, the second bladder (146; 146') being thereafter inflated to a fully expanded state for deforming the first bladder (144; 144') axially between the band and the second bladder (146; 146') so that the axial end portion of the band is caused to further turn about the aforesaid fold line until the axial end portion of the band is received on an adjacent axial portion of the band.