Shaped groove countermatrix for rotary groove pulley matrix and countermatrix bending head pipe bending machines

摘要

A shaped groove countermatrix for a rotary groove pulley matrix and countermatrix head pipe bending machines has a semicircular cross- sectional tract and an end tract (2) tapered, both longitudinally and transversely according to substantially elliptic profiles (20). With respect to the preceding tract, an edge of a groove (10) remains at the same level. The end tract (2) has its cross section substantially determined by the arcs (4, 4') of two ellipses (12) with their major axes (6, 6') parallel to and slightly offset with respect to a plane of longitudinal symmetry (8) of the groove (10) which is inferiorly radiused by an arc which is elliptic too. The tapering of the end tract (2), starting from a substantially parabolic profile (14), has its axis on the plane of longitudinal symmetry (8) of the groove (10) and its convexity (16) at a short distance from the exit edge (18) of the groove (10). A well (22) has a plug (22') which allows for feeding a lubricating fluid vein onto the groove (10) which is in fluid communication through a hole (24) via a wick (24'). A check valve (26) allows recharge of the well (22) with the lubricating fluid.