Hydraulic tube bender

A hydraulic tube bender comprising

• a hydraulic cylinder having a piston rod extending forward from one end thereof, the rod adapted to reciprocate along a longitudinal axis of the cylinder in response to changes in oil pressure within the cylinder;
• a block coupled to the cylinder;
• a pair of arms pivotally coupled to and extending forward from the block in a first plane offset below and parallel the axis;
• a rigid offset bracket coupled to the rod forward of the block, the bracket having an aperture receiving the piston rod and a stud vertically offset above the aperture,
• a brace coupled to the bracket below the arms and extending transverse the axis;
• a mandrel coupled to the stud and defining a second plane parallel to and offset above the axis, the mandrel having a curved surface normal to the first plane, the curved surface further having a groove adapted to receive and bear against a tube;
• forming die means coupled to the arms a select distance from the cylinder and having two forming surfaces coplanar with the groove, one each of the forming surfaces positioned on either side of the axis, for forming the tube in response to pressure exerted through the mandrel by the cylinder rod,
• whereby the tube bender may cause the mandrel to push the tube between the forming surfaces, thereby bending the tube around the mandrel and into a selected angle in the first plane.

A dynamic pressure adapter for a center-push tube bender, the tube bender having a mandrel reciprocating along a longitudinal axis, pressure means for causing the mandrel to reciprocate, two forming die means coplanar with the mandrel, and positioning means for positioning the forming die means on opposite sides of the axis, the dynamic pressure adapter comprising

• pivot axis rigidly coupled to the forming die means;
• two arcuate plates, one plate rigidly coupled to one of the pivot axles, the plates defining a plane parallel to and offset below the axis:
• a pneumatic cylinder coupled to the positioning means and having a pneumatic piston rod adapted to reciprocate in the plane in response to pressure changes in the pneumatic cylinder;
• a pulley mounted to one end of the pneumatic piston rod;
• and
• tether means extending from one arcuate plate through the pulley to the other arcuate plate, for tethering the plates to the pneumatic piston rod,
• whereby the pneumatic cylinder applies torque uniformly to each of the forming dies through the tether means and the pivot axles in response to pressure in the pneumatic cylinder, thereby causing the forming dies to apply pressure to the tube and the mandrel.

An improved method of bending tubing comprising the steps of providing a tube bender having

• a mandrel means adapted to reciprocate along a longitudinal axis in a first plane;
• pressure means for causing the mandrel to reciprocate;
• a positioner coupled to the pressure means;
• two pivot axles coupled to the positioner on opposite sides of the axis;
• two forming dies, one coupled to each of the pivot axles, each die having at least one forming surface coplanar with the mandrel;
• two arcuate plates, one coupled to each of the pivot axles opposite the forming dies;
• a tether coupled to the arcuate plates;
• and
• resistance means coupled to the tether for applying torque resistance to the forming dies through the tether, the arcuate plates and the pivot axles;
• positioning a tube between the mandrel and the forming die;
• then
• operating the pressure means to cause the mandrel to push the tube toward and to engage the forming dies;
• then
• operating the resistance means to apply resistive torque through the forming dies against the tube;
• then
• operating the pressure means to force the tube to move between the forming dies, thereby bending the tube into a selected angle in the first plane.

A hydraulic tube bender comprising

• a hydraulic cylinder having a piston rod extending forward from one end thereof, the rod adapted to reciprocate along a longitudinal axis of the cylinder in response to changes in oil pressure within the cylinder;
• a mandrel coupled to the rod and defining a first plane parallel to the axis, the mandrel having a curved surface normal to the first plane, the curved surface further having a groove adapted to receive and bear against a tube;
• a block coupled to the cylinder;
• a pair of arms pivotally coupled to and extending forward from the block in a second plane offset below and parallel the first plane;
• forming die means coupled to the arms a select distance from the cylinder and having two forming surfaces coplanar with the groove, one each of the forming surfaces positioned on either side of the axis, for forming the tube in response to pressure exerted through the mandrel by the cylinder rod:
• and
• a rigid offset bracket coupled between the rod and the mandrel, the bracket having an aperture receiving the piston rod and a stud vertically offset above the aperture and received within the mandrel,
• whereby the mandrel and the first plane are offset above the axis a selected distance and whereby the tube bender may cause the mandrel to push the tube between the forming surfaces, thereby bending the tube around the mandrel and into a selected angle in the first plane.

A hydraulic tube bender comprising

• a hydraulic cylinder having a piston rod extending forward from one end thereof, the rod adapted to reciprocate along a longitudinal axis of the cylinder in response to changes in oil pressure within the cylinder:
• a mandrel coupled to the rod and defining a first plane parallel to the axis, the mandrel having a curved surface normal to the first plane, the curved surface further having a groove adapted to receive and bear against a tube;
• a block coupled to the cylinder;
• a pair of arms pivotally coupled to and extending forward from the block in a second plane offset below and parallel the first plane;
• a pivot axle coupled to and extending through each of the arms;
• a forming die rigidly mounted to each of the pivot axles, the forming die being coplanar with the mandrel and bearing a forming surface normal to the first plane;
• two arcuate plates, one each mounted to one of the pivot axles, the plates defining a third plane parallel to and offset below the second plane;
• a pneumatic cylinder coupled to the block and having a pneumatic piston rod adapted to reciprocate in the third plane in response to pneumatic pressure changes in the pneumatic cylinder;
• a pulley mounted to the end of the pneumatic piston rod;
• and
• tether means extending from one arcuate plate through the pulley to the other arcuate plate, for tethering the tracks to the pneumatic piston rod.

An improved method of bending tubing comprising the steps of providing a tube bender having

• a mandrel means adapted to reciprocate along a longitudinal axis in a first plane;
• pressure means reciprocating in a second plane for causing the mandrel to reciprocate;
• an offset bracket coupled between the mandrel means and the pressure means;
• a positioner coupled to the pressure means;
• two forming dies, one each coupled to the positioner on opposite sides of the axis, each die having at least one forming surface coplanar with the mandrel;
• and
• torque means coupled to the forming dies for applying torque to the forming die;
• positioning a tube between the mandrel and the forming die;
• then
• operating the pressure means to cause the mandrel to push the tube toward and to engage the forming dies;
• then
• operating the torque means to apply resistive torque through the forming dies against the tube:
• then
• operating the pressure means to force the tube to move between the forming dies, thereby bending the tube into a selected angle in the first plane.