Pusher apparatus for multi-axis tube bender

For use with a tube bending machine in which a tube having a free end is continuously pushed under force along its axis through a fixed die and a movable die in order to continuously bend a curvature into said tube, an apparatus for applying pushing force to said tube as it is bent, comprising,

• a flexible bending mandrel having an axial length substantially equal to the distance between said fixed and movable die and sized to make a close slip fit inside of said tube so as to maintain the shape of said tube as it is bent,
• a piloting plug sized to make a close slip fit inside of said tube and having a predetermined axial thickness,
• a pusher bar assembly having a hollow sleeve with a diameter substantially equal to said tube and a free end abuttable with said tube free end, said hollow sleeve also having an axial interior length at least equal to the sum of said mandrel axial length and plug axial thickness,
• a mandrel bar connected to said mandrel and adapted to slide independently of said pusher bar assembly axially through said hollow sleeve and through said plug so as to push said mandrel, tending to extend it axially out of said hollow sleeve, or to pull said mandrel, tending to withdraw it axially into said hollow sleeve,
• a stop means to stop said mandrel bar when said mandrel is located within said tube between said fixed and movable die, and,
• push-pull means engageable between said mandrel bar and said plug to push said plug with said mandrel pull bar when said mandrel bar is extending and pull said plug when said mandrel bar is withdrawing, said push-pull means being located on said mandrel bar, relative to said mandrel, such that, when said stop means is engaged, said plug extends partially out of said hollow sleeve,
• whereby, said mandrel bar may be pulled to withdraw said plug and mandrel to a stored position within said hollow sleeve, from which stored position said hollow sleeve free end may be abutted with said tube free end and said mandrel bar pushed independently through said hollow sleeve and plug to extend said assuring that said plug extends out of said hollow sleeve far enough to fit within both said hollow sleeve and tube free ends, thereby allowing said pusher bar to apply a pushing force to said tube as it is bent and supported by said mandrel, after which said mandrel bar may be pulled back to again withdraw said mandrel and plug to stored position.