Device for bending thin-walled pipes

摘要

Device for bending thin-walled pipes from inside by embossing them with eccentric corrugations, comprising an expander block introducible into the pipe to the point of bend, the block being formed by a supporting shoe and a punch whose side facing the pipe has a toroidal surface following the shape of the desired corrugation and which is mounted on the shoe with a provision for positive movement in a radial direction to the pipe surface for making the corrugation on the pipe. In the cross-sectional plane of the pipe the punch has the shape of a ring which is open at the side of the shoe and is composed of individual elements around its parameter, each element being articulated to a movable member of one of the power cylinders whose axes are arranged radially to a cross-sectional plane of the pipe while their stationary members are connected with the supporting shoe. The stroke of the movable elements of the power cylinders is practically equal to the height of the corrugation on the corresponding generatrix of the pipe.