Weight recording apparatus

Claim 1

WEIGHT RECORDING APPARATUS ADAPTED TO SENSE AND RECORD THROUGH A RECORDING INSTRUMENT VARIATIONS IN DRILLING WEIGHT APPLIED TO A DRILL RIG COMPRISING, MEANS CONNECTED TO A PORTION OF THE RIG WHICH PORTION UNDERGOES CHANGES IN LENGTH IN ACCORDANCE WITH VARIATIONS IN WEIGHT APPLIED TO THE RIG, SAID MEANS BEING SLIDABLE AT ONE END IN RELATION TO THE RIG AND INCLUDING A PLUNGER MOVABLE IN RESPONSE SLIDABLE MOVEMENT OF THE END OF SAID MEANS CAUSED BY CHANGES IN LENGTH OF THE PORTION, A TRANSMITTER ASSEMBLY INCLUDING A CYLINDER AND A PISTON DISPOSED FOR ACTUATION BY SAID PLUNGER FOR DISPLACING FLUID FROM SAID CYLINDER CORRESPONDING TO THE EXTENT OF MOVEMENT OF SAID PLUNGER, SAID PLUNGER AND TRANSMITTER PISTON BEING BIASED IN THE DIRECTION OF MOVEMENT OF SAID MEANS CAUSED BY AN INCREASE IN WEIGHT ON THE RIG PORTION, AND A RECEIVER ASSEMBLY INCLUDING A PISTON RESPONSIVE TO THE FLUID DISPLACED FROM SAID TRANSMITTER FOR ACTUATING THE RECORDING INSTRUMENT, SAID RECEIVER PISTON BEING BIASED IN A DIRECTION GENERALLY OPPOSING THE BIAS OF SAID PLUNGER AND TRANSMITTER PISTON, AN ADJUSTABLE VOLUME PILOT CYLINDER IN SAID RECEIVER ASSEMBLY FOR REGULATING THE INITIAL SETTING OF SAID RECEIVER PISTON AND MEANS FOR VARYING THE VOLUME OF SAID PILOT CYLINDER AFTER ASSEMBLY OF SAID APPARATUS.