Rotary internal pipe bending mandrel

Rotary internal pipe bending mandrel, wherein sets of pipe engagement elements at opposite sides of the pipe interior are actuated by generally radially disposed toggle elements which expand and retract the pipe engagement elements by rotations of a central assembly. The elements which support the pipe engagement elements are disposed in circularly spaced groups which are axially spaced along the direction of the pipe, and each group is separately expanded by a separate fluid motor assembly. The apparatus has improved the load bearing characteristics because it has positive end engagements of the toggles, whereby the pins or shafts on which the toggles are pivotally mounted are not excessively strained.