A shaped groove countermatrix for rotary matrix pipe bending machines

摘要

The subject of the invention is a shaped groove countermatrix for rotary groove pulley matrix and countermatrix head pipe bending machines, comprising a semicircular cross section tract and an end tract (2) tapered, both longitudinally and transversely according to substantially elliptic profiles (20), with respect to the preceding tract, the edge of the groove remaining at the same level, which end tract has its cross section substantially determined by the arcs (4, 4') of two ellipses with their major axes parallel to and slightly offset with respect to the plane of longitudinally simmetry (8) of the groove, inferiorly radiused by an arc which is elliptic too (12), the tapering of the end tract (2) starting from substantially parabolic profile (14) having its axis on the plane of longitudinal simmetry (8) of the groove and its convexity (16) at a short distance from the exit section (18) of the groove; as well as endowed with means (22, 22') for feeding a lubricating fluid veil onto the groove, in fluid communication with that through a hole (24) by means of a wick (24') and endowed with recharge means (26).