Power wrench and power slip

Claim 1

A DRILL ROD POWER WRENCH COMPRISING A ROTATABLE HEAD PORTION SUPPORTED BY A FRAME, SAID HEAD PORTION HAVING AN OPENING THEREIN FOR RECEIVING A DRILL ROD WITH THE LONGITUDINAL AXIS THEREOF SUBSTANTIALLY COINCIDENT WITH THE AXIS OF ROTATION OF SAID HEAD PORTION, SAID HEAD PORTION HAVING A PLURALITY OF PIVOTALLY MOUNTED ARMS HAVING END PORTIONS SWINGABLE INTO AND AWAY FROM SAID OPENING, A FIRST POWER OPERATED MEANS MOUNTED ON SAID HEAD PORTION CONNECTED TO SAID ARMS FOR SWINGING SAID ARMS, A FLUID OPERATED EXTENSIBLE CYLINDER MOUNTED ON SAID FRAME OPERATIVELY CONNECTED TO SAID HEAD PORTION BY AN ELONGATED FLEXIBLE ELEMENT SECURED TO THE PERIPHERY OF SAID HEAD PORTION FOR ROTATIN SAID HEAD PORTION INDEPENDENTLY OF SAID FIRST POWER OPERATED MEANS, A PAIR OF COOPERATING LEVERS HAVING OPPOSABLE SURFACES PIVOTALLY MOUNTED ON SAID FRAME AND POSITIONED BELOW SAID ROTATABLE HEAD, SAID LEVERS SWINGABLE BY SECOND POWER OPERATED MEANS TO ENGAGE SAID OPPOSABLE SURFACE WITH SUCH DRILL ROD, AND A PROJECTION MOUNTED ON SAID OPPOSABLE SURFACE OF AT LEAST ONE OF SAID LEVERS FOR ENGAGING NOTCHES ON SAID FIRST DRILL ROD SPACED FROM NOTCHES ON A SECOND SUCH DRILL ROD THREADEDLY SECURED TO SAID FIRST DRILL ROD ENGAGED BY SAID PIVOTALLY MOUNTED ARMS WHEREBY SAID LEVERS HOLD STATIONARY A DRILL ROD WHILE SAID ARMS MOUNTED ON SAID ROTATABLE HEAD ROTATE SAID SECOND DRILL ROD TO THREADEDLY DISENGAGE SAID SECOND DRILL ROD FROM SAID FIRST DRILL ROD.