71554473
Apr 13, 1948
Jul 4, 1950
OIL-FIELD WELL SERVICING HOISTS; OIL WELL CABLE TOOL RIGS; OIL WELL ROTARY DRILLING RIGS; ROTARY TABLE DRIVE ASSEMBLIES; SPUDDING ASSEMBLIES; CLUTCHES, AIR-OPERATED AND MECHANICALLY OPERATED; CATHEADS; SIDE BOOMS MOUNTED ON TRACTORS; CRANES MOUNTED ON TRACTORS; SINGLE AND MULTIPLE ENGINE DRAW WORKS; PORTABLE DERRICK RIGS; OIL WELL DERRICKS; OIL WELL TELESCOPING MASTS; OIL WELL MUD PUMP DRIVES; OILFIELD WINCHES; PIPE-LINE WINCHES; INDUSTRIAL WINCHES; VARIABLE SPEED DRIVE MECHANISMS; CORE-DRILL SLUSH-PUMP MOUNTINGS; TRENCH BACK FILLERS; PIPE BENDERS; TRACTOR TYPE GENERAL WELL SERVICING UNITS WITH VARIOUS ASSEMBLIES FOR CLEANOUT, DEEPENING, OR DRILLING IN WITH CABLE TOOLS, AND FOR ROTARY AND CORE DRILLING OPERATIONS
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