A clamp member and a counter pressure member are hingedly connected together about a rotary axis, and a fitting portion of a fitting protrusion that is positioned in a fitting recess is located at a foreside in an advancing direction of the pipe relative to a position where a bending operation of the pipe is initiated, and a mating portion at which a first groove part of the clamp member and a second groove part of a counter pressure member mate is located at a backside in the advancing direction of the pipe relative to the position where the bending operation of the pipe is initiated. The counter pressure member comprises a first member supported rotatably about the rotary axis, a second member detachably connected to the first member, and a third member detachably connected to the second member, which are connected together by a common connecting member (e.g., bolt).

A tie bar tensioning system that allows a bending machine operator to removably couple an upper end of a bend die post of the bending machine to a base of the bending machine via a tie bar, and to lock the tie bar in a tensioned position. The tensioning system includes a stationary member and a rotatable member, each with aligned tie bar passages for receiving the one end of the tie bar. Both the stationary member and the rotatable member include respective engagement surfaces, with the rotatable member engagement surface being rotatable relative to the stationary member engagement surface between a released position and a tensioned position whereat the rotatable member is selectively lockable. The rotation of the rotatable member with the stationary engagement surface in engagement with the stationary engagement surface longitudinally displacing the rotatable member relative to the stationary member.

A clamp member and a counter pressure member are hingedly connected together about a rotary axis, and a fitting portion of a fitting protrusion that is positioned in a fitting recess is located at a foreside in an advancing direction of the pipe relative to a position where a bending operation of the pipe is initiated, and a mating portion at which a first groove part of the clamp member and a second groove part of a counter pressure member mate is located at a backside in the advancing direction of the pipe relative to the position where the bending operation of the pipe is initiated. The counter pressure member comprises a first member supported rotatably about the rotary axis, a second member detachably connected to the first member, and a third member detachably connected to the second member, which are connected together by a common connecting member (e.g., bolt).

A pipe bend die unit comprises a clamp member having a first groove part of half-circular cross section on an outer peripheral surface thereof with a fitting recess extending in a peripheral direction by a first predetermined length on a planar surface perpendicular to a rotary axis, and a counter pressure member having a second groove part of half-circular cross section formed on an outer peripheral surface thereof, and a fitting protrusion extending in a peripheral direction by a second predetermined length from a tip end portion of the second groove part. The fitting protrusion is positioned in the fitting recess so that the first and second groove parts are combined to form a pipe-receiving groove of half-circular cross section. The counter pressure member and the clamp member are hingedly connected to one another so as to be rotatable relative to each other about the rotary axis.

Provided is a mandrel which is inserted into a pipe material when the pipe material is bent, the mandrel including: a core member having a rod-shaped main body portion and a small-diameter portion which is provided on one end side of the main body portion and which is thinner than the main body portion; and a front end member which is provided on one end side of the core member and which is formed integrally with the core member so as to cover the small-diameter portion.

A tie bar tensioning system that allows a bending machine operator to removably couple an upper end of a bend die post of the bending machine to a base of the bending machine via a tie bar, and to lock the tie bar in a tensioned position. The tensioning system includes a stationary member and a rotatable member, each with aligned tie bar passages for receiving the one end of the tie bar. Both the stationary member and the rotatable member include respective engagement surfaces, with the rotatable member engagement surface being rotatable relative to the stationary member engagement surface between a released position and a tensioned position whereat the rotatable member is selectively lockable. The rotation of the rotatable member with the rotatable member engagement surface in engagement with the stationary engagement surface longitudinally displacing the rotatable member relative to the stationary member.

A mandrel assembly for a tube bending machine has a mandrel body, a mandrel rod, a series of articulation elements connected to one another and to the mandrel body through respective cylindrical or spherical hinges, and a network of lubricant transport channels formed through the mandrel body and communicating with a lubricant feed passage formed along the mandrel rod. The network of lubricant transport channels has a plurality of lubricant outlet ports arranged on the distal end or on a peripheral surface of the mandrel body. A plurality of through-holes extending along a longitudinal direction of the respective articulation element is formed through each of the articulation elements. The through-holes are configured to convey a lubricant to a front side of an extreme distal articulation element of the series of articulation elements. The extreme distal articulation element has a deflector element.