DIE FOR PRODUCTION OF CIRCULAR PIPES FROM A SHEET MATERIAL OF U-SHAPED BLANKS Russian patent published in 2005 - IPC

FIELD: mechanical engineering; production of circular metal or polymeric pipes.

SUBSTANCE: the invention is dealt with the field of mechanical engineering and may be used for production of circular metal or polymeric pipes from the prefabricated U-shaped blanks with the sheet material edges bent and with their intersection as well as for production of metal-polymeric pipes with following extrusive deposition on a circular metal pipes of internal and-or external polymeric covers. The device contains a body and a hole executed asymmetric to its longitudinal axis. In the geometrical plane A-A, that is passing through a midpoint of the bend with intersection of the edges of the sheet material of the U-shaped blank and through a longitudinal axis of the hole, the hole generatrix located on the side of the bent edge and opposite to the edge of the hole, in which in its outlet part of the hole the sheet material edges are bent with intersection, it is rectilinear and in parallel to the longitudinal axis of the hole. A counter generatrix in the geometrical plane A-A is curvilinear. The section of the hole located in front of its outlet part has a cylindrical wall, and the section of the hole located behind its inlet part and in front of the cylindrical wall has a curvilinear wall. The rectilinear generatrices of the cylindrical wall of the section of the hole spaced by equal distances from the mentioned rectilinear generatrix, on one side of the geometrical plane A-A have the lengths exceeding the lengths of the rectilinear generatrices of the cylindrical walls of the bore section located on the other side of the geometric plane A-A, and with the smoothly diminishing lengths. These rectilinear generatrices are smoothly conjugated with the corresponding curvilinear generatrices of the section of the hole with the curvilinear wall. A located in the geometrical plane A-A curvilinear generatrix with a smaller distance from the longitudinal axis is conjugated with a linear generatrix with a capability to form a cylindrical surface before the outlet part of the hole. The curvilinear generatrix with a bigger distance from the longitudinal axis in the geometrical plane A-A is conjugated with the field of the least length of a cylindrical section. The invention allows to increase the speed of drawing, the passive hardness of the die and quality of a produced pipe.

EFFECT: the invention allows to increase the speed of drawing, the passive hardness of the die and quality of a produced pipe.

3 cl, 6 dwg