Form tool for producing curved duct sections - forces duct into ring gap between core and tool body

摘要

A sheet metal duct (61) which has a circular cross section is bent to form an elbow joint up to 90 deg. A press tool (60) which can be split open, has a built up core (66-68) so that a ring chamber (69) in the shape of the finished duct bend is obtained. The initially straight duct section has one end face at an incline to compensate the unequal metal flow during the forming operation. A hydraulically operated piston (71) forces the straight duct into the ring gap between form tool and cores. A material flow, similar to that on an extrusion process is obtained. It is thus possible to produce duct bends of very small bending radius.