Apparatus for bending rectangular tubes

An apparatus for bending a rectangular tube having first and second pairs of opposed parallel sides defining unequal major and minor widths respectively, said apparatus comprising:

• a bending die having a bending surface defining an arc of a cylinder, said bending die being selectively rotatable about the axis of the cylinder;
• a clamp die having parallel major and minor clamping surfaces respectively for clamping a selected one of the major and minor width sides of the rectangular tube against the bending surface of the bending die, said clamp die being movable through a generally circular arc relative to the axis of the cylindrical bending surface of the bending die to bend the rectangular tube around said bending surface, said clamp die including opposed leading and trailing ends which respectively lead and trail the clamp die through its movement for bending the rectangular tube;
• a pressure die disposed substantially adjacent the bending die and the trailing end of said clamp die, said pressure die having parallel major and minor pressure surfaces respectively for engaging a selected one of the major and minor width sides of the rectangular tube, said pressure die being operative to move in a generally tangential direction relative to the bending die toward the clamp die as the clamp and bending dies move about said axis, selected portions of said pressure die nearest the bending surface of the bending die being movable relative to the remainder of the pressure die toward and away from the trailing end of the clamp die, whereby the movable portion of said pressure die is operative to move upon contact with the clamp die, thereby enabling the remainder of the pressure die to be urged toward the clamp die as the clamp die moves through the circular arc.

An apparatus for bending a rectangular tube having first and second pairs of opposed parallel sides defining unequal major and minor widths respectively, said apparatus comprising:

• a bending die having a bending surface defining an arc of a cylinder, said bending die being selectively rotatable about the axis of the cylinder;
• a clamp die having parallel major and minor clamping surfaces respectively for clamping a selected one of the major and minor width sides of the rectangular tube against the bending surface of the bending die, the clamp die further comprising a tongue disposed intermediate said major and minor clamping surfaces and extending perpendicularly therefrom, said tongue extending from said major clamping surface a distance generally equal to or greater than the minor width of said rectangular tube, and extending from said minor clamping surface a distance generally equal to or greater than the major width of said tube, said clamp die being movable through a generally circular arc relative to the axis of the cylindrical bending surface of the bending die to bend the rectangular tube around said bending surface, said clamp die including opposed leading and trailing ends which respectively lead and trail the clamp die through its movement for bending the rectangular tube;
• a pressure die disposed substantially adjacent the bending die and the trailing end of said clamp die, said pressure die having parallel major and minor pressure surfaces respectively for engaging a selected one of the major and minor width sides of the rectangular tube, said pressure die being operative to move in a generally tangential direction relative to the bending die toward the clamp die as the clamp and bending dies move about said axis, selected portions of said pressure die nearest the bending die being movable relative to the remainder of the pressure die toward and away from the trailing end of the clamp die, whereby the movable portion of said pressure die will move enabling the remainder of the pressure die to be urged toward the clamp die as the clamp die moves through the circular arc.