Welding work centering chuck

Claim 1

A THREE JAW CHUCK COMPRISING A THREE SIDED BODY WITH AN ARM EXTENDING OUTWARDLY FROM EACH CORNER THEREOF WITH THE AXIS OF SAID ARMS EXTENDING RADIALLY FROM THE CENTER OF A CIRCLE CIRCUMSCRIBED WITHIN SAID SIDES, EACH ARM PROVIDING A SLOT AXIALLY EXTENDING THEREIN AND OF MODIFIED H-SHAPE IN CROSS-SECTION, A JAW OF CROSS-SECTION TO RIDE SLIDABLY IN EACH SLOT AND EXTENDING FORWARDLY IN STEPPED SUCCESSION TO PROVIDE A PLURALITY OF WORK CONTACTING SURFACES TRANSVERSE TO THE RESPECTIVE ARM AXIS WITH THE MOST FORWARD SURFACE OUTERMOST, SAID BODY PROVIDING A CENTRAL INNER RECESS CONCENTRIC WITH THE SIDES THEREOF AND A GEAR BOX IN SAID RECESS AND EXTENDING REARWARDLY THEREFROM TO SPACE SAID BODY FROM A BACKING PLATE PROVIDED FOR SAID CHUCK, SAID GEAR BOX COMPRISING THREE CENTRALLY BORED PLATES CONCENTRIC WITH SAID RECESS WITH CORNERS ADJOINED IN ASSEMBLY, DRIVE ELEMENTS COMPRISING A PINION SHAFT, A PINION-GEAR SHAFT, AND A GEAR SHAFT DISPOSED WITH PINIONS AND GEARS MESHED WITHIN SAID GEAR BOX, WITH ONE OF SAID SHAFTS EXTENDING THROUGH EACH RESPECTIVE GEAR BOX BEARING PLATE AND THREADEDLY EXTENDING THROUGH THE CHUCK JAW IN THE RESPECTIVE SLOT OUTWARDLY THEREOF, THE OUTER END PORTIONS OF SAID SHAFTS TERMINATING IN NON-CIRCULAR OUTER ENDS, AND SAID CHUCK INCLUDING CENTRALLY BORED SLOT END ASSEMBLIES MOUNTED UPON THE OUTER END OF EACH ARM TO EXTEND ACROSS THE SLOT THEREIN, THE OUTER PORTION OF EACH SHAFT EXTENDING OUTWARDLY THROUGH THE SLOT END ASSEMBLY THEREFOR, SAID PINION-GEAR AND ITS JAW HAVING ONE HAND OF THREADS AND SAID PINION AND SAID GEAR AND THEIR RESPECTIVE JAWS HAVING THE OTHER HAND OF THREADS, WHEREBY UPON ONE OF NON-CIRCULAR SHAFT ENDS BEING CONTACTED TO ROTATE IT AND THE DRIVE ELEMENT THEREON, THE OTHER MESHED DRIVE ELEMENTS ARE ROTATED THEREBY TO MOVE SAID JAWS UNIFORMLY INWARDLY AND OUTWARDLY DEPENDENT UPON THE HAND OF ROTATION, WHEREBY SAID STEPPED SURFACES MAY SELECTIVELY GRASP WORK TO BE WELDED.