Automatic tension control systems for oil well drill lines

Claim 1

IN A SYSTEM FOR REGULATING DRILL LINE TENSION AS SUCCESSIVELY DEEPER FORMATIONS ARE PENETRATED, DRUM MEANS MOUNTED TO SUPPORT A SUPPLY OF SAID DRILL LINE AND PROVIDED WITH BRAKING MEANS THEREON, MEANS INCLUDING A LINE AND SPOOL FOR EXERTING A VARIABLE FORCE ON SAID BRAKING MEANS, A PLANETARY GEAR ASSEMBLY MOUNTED TO ROTATE SIMULTANEOUSLY WITH SAID SPOOL, A FIRST ELECTRIC MOTOR MOUNTED TO SUPPLY INPUT TORQUE TO SAID PLANETARY GEAR ASSEMBLY TO ROTATE SAID SPOOL IN ONE DIRECTION, A PIVOTALLY MOUNTED FRICTION WHEEL ASSEMBLY ADAPTED TO ENGAGE SAID DRUM MEANS FOR SIMULTANEOUS ROTATION THEREWITH, MECHANISM INCLUDING A SECOND ELECTRIC MOTOR, HYDRAULIC MEANS DRIVEN BY SAID SECOND ELECTRIC MOTOR, SAID HYDRAULIC MEANS BEING ADAPTED TO GENERATE FLUID PRESSURE TO ACTUATE SAID FRICTION WHEEL ASSEMBLY INTO ENGAGEMENT WITH SAID DRUM, A PRESSURE SENSITIVE SWITCH RESPONSIVE TO SAID FLUID PRESSURE TO OPERATIVELY CONNECT SAID FIRST ELECTRIC MOTOR TO A SOURCE OF POWER, MEANS INCLUDING A DIAPHRAGM TENSION SENSOR AND BOURDON TUBE RESPONSIVE TO TENSION IN SAID DRILL LINE TO INITIATE FLOW OF ELECTRIC POWER TO SAID FIRST MOTOR, A WORM AND GEAR IN SPACED RELATION TO SAID PLANE-