Stud-pulling crane

Claim 1

IN AN ALUMINUM REDUCTION PLANT HAVING MULTIPLE REDUCTION CELLS EACH OF WHICH EMPLOYS A PLURALITY OF VERTICALLY DISPOSED CURRENT-CONDUCTING STUDS, SAID STUDS HAVING THEIR LOWER ENDS SET INTO A CARBON BLOCK AND HAVING THEIR UPPER ENDS REMOVABLY CLAMPED TO A BUS BAR, THE STUDS EACH PRESENTING A HEAD WHICH IS NON-CIRCULAR IN SECTION AND HAVING A CROWN PORTION OF SAID HEAD UNDERCUT WITH V-SLOTS IN EACH OF THE OPPOSITE SIDES THEREOF, THE COMBINATION WITH SAID CELLS AND THEIR STUDS OF A TRAVELING CRANE MOUNTED FOR OVERHEAD MOVEMENT ABOVE SAID CELLS, A TROLLEY CARRIED BY THE CRANE AN MOVABLE TRANSVERSELY THEREOF, A VERTICALLY DISPOSED CYLINDRICAL SHELL CARRIED BY SAID TROLLEY, A FIRST CYLINDER MEMBER JOURNALED WITHIN THE SHELL FOR ROTATION ABOUT THE CENTER OF THE LATTER AS AN AXIS AND SECURED AGAINST ENDWISE MOTION WITH RESPECT THERETO, A SECOND CYLINDER MEMBER JOURNALED FOR ENDWISE SLIDING MOVEMENT WITHIN THE FIRST CYLINDER MEMBER, MEANS OPERATIVELY ASSOCIATED WITH SAID FIRST AND SECOND CYLINDER MEMBERS ACTING TO HOLD SAID SECOND CYLINDER MEMBER AGAINST ROTATION WITH RESPECT TO THE FIRST CYLINDER MEMBER WHEN THE LATTER REACHES ITS LOW LIMIT OF TRAVEL, A SPINDLE JOURNALED FOR ENDWISE SLIDING MOVEMENT WITHIN THE SECOND CYLINDER MEMBER AND HELD AGAINST ROTATION RELATIVE THERETO, A CHUCK UPON THE LOWER END OF SAID SPINDLE HAVING A DOWNWARDLY FACING SOCKET FORMED IN MATING CORRESPONDENCE WITH SAID NONCIRCULAR HEAD OF THE STUD AND, ABOVE AND COMMUNICATING WITH THE SOCKET, PRESENTING A RECESS OF EXPANDED WIDTH CONNECTING WITH THE SIDE WALLS OF THE SOCKET BY SLOPING FLANKS, THE CROWN PORTION OF THE STUD HEAD PROJECTING INTO SAID RECESS, CHUCK JAWS RECEIVED FOR VERTICAL MOTION WITHIN THE RECESS WITH LOWER FACE PORTIONS THEREOF RIDING ALONG SAID SLOPING FLANKS AND BY ACTION OF THE LATTER AS THE JAWS MOVE DOWNWARDLY WITHIN THE RECESS CAUSED TO CLOSE UPON AND ENGAGE IN THE SLOTS OF THE STUD HEAD, POWER MEANS OPERATIVELY ASSOCIATED WITH THE CHUCK JAWS FOR RAISING AND LOWERING THE CHUCK JAWS, MEANS YIELDINGLY SPREADING SAID JAWS SO THAT THE LATTER WILL OPEN IN RESPONSE TO SAID RAISING OF THE JAWS POWER MEANS OPERATIVELY ASSOCIATED WITH THE CRANE AND THE TROLLEY FOR REGULATING THE MOVEMENT OF THE CRANE AND THE TORLLEY SO AS TO BRING THE SOCKET OF THE CHUCK INTO VERTICAL REGISTRATION WITH THE HEAD OF A SELECTED STUD WHICH IS TO BE PULLED, AND POWER MEANS OPERATIVELY ASSOCIATED WITH THE TWO CYLINDER MEMBERS AND THE SPINDLE FOR TELESCOPING THE TWO CYLINDER MEMBERS AND THE SPINDLE SO AS TO RAISE AND LOWER THE CHUCK AND FOR TURNING THE FIRST CYLINDER MEMBER SO AS TO TWIST THE CHUCK.