Flexible mandril for pipe or tube bending

Claim 1

IN A PIPE AND TUBE BENDING APPARATUS, A FLEXIBLE MANDRIL POSITIONABLE WITHIN A PIPE OR TUBE TO PREVENT BUCKLING DURING BENDING; A STATIONARY HEAD OF CYLINDRICAL FORM SNUGLY AND SLIDABLY POSITIONABLE WITHIN A TUBE REARWARDLY OF THE PORTION TO BE BENT AND INCLUDING A SPHERICALLY SHAPED INNER END OF A RADIUS SUBSTANTIALLY THE SAME AS THE INNER RADIUS OF THE TUBE; AND A SERIES OF CONTACTING AND OVERLAPPING SPHERES OF THE SAME RADIUS FLEXIBLY CONNECTED TO EACH OTHER IN A LINE AND TO THE INNER END OF SAID HEAD RESPECTIVELY; EACH SPHERE HAVING A BORE, SAID BORE TERMINATING IN AN OUTWARDLY OPENING SPHERICALLY SHAPED SURFACE OF THE SAME RADIUS COOPERATIVELY AND GUIDABLY RECEIVING THE SPHERICAL END OF SAID HEAD AND THE SERIES OF SPHERES SUCCESSIVELY, THE FLEXIBLE CONNECTION BETWEEN SAID SPHERES AND HEAD INCLUDING A SERIES OF LINKS; SAID HEAD HAVING A BORE, EACH OF SAID BORES TERMINATING IN A COUNTERBORE DEFINING A STOP SHOULDER; AND SAID LINKS EXTENDING INTO SAID BORES; AN ENLARGED ANNULAR FLANGE AT ONE END OF EACH LINK RETAININGLY ENGAGING SAID STOP SHOULDERS RESPECTIVELY; OPPOSED LATERALLY EXTENDING ARCUATE BOSSES AT THE OTHER END OF EACH LINK, EXCEPT THE FIRST LINK, NESTED AND RETAINED WITHIN OPPOSED ARCUATE UNDERCUT RECESSES FORMED IN THE ONE ENDS OF ADJACENT LINKS; AND MEANS SECURING THE FIRST LINK WITHIN SAID HEAD.