METHOD OF MEASURING THREADED JOINT TIGHTENING FORCE AND TORQUE WRENCH TO THIS END Russian patent published in 2011 - IPC G01L5/24 

FIELD: physics.

SUBSTANCE: proposed method comprises applying torque to tightened thread joint, driving said threaded joint to turn its through preset angle not exceeding 2…4° of torque measurement, additional turn of said joint through the same angle with changing torque, measurement of torque, and screwing off threaded joint through preset angle equal to that of turn in tightening with measurement of screwing-off torque. Then joint is turned is additionally turned through the same angle with measurement with screwing-off torque and determining axial tightening force as , where F_t is axial tightening force, P is thread pitch, M1_tight is tightening torque in initial turn through preset angle, M2_tight is tightening torque in additional turn through preset angle, M1_screw-off is torque in screwing-off through preset angle, M2_screw-off is torque in additional screwing-off through preset angle. Torque wrench comprises torque pickup connected to amplifier input. Amplifier output is connected to ADC input. It comprises also first and second memory registers with their data inputs connected to ADC outputs and their outputs connected to data inputs of computer with its data outputs connected to digital indicator inputs, angle pickup with its output connected to count input of pulse counter with its outputs connected to decoder inputs, first OR element with its output connected first indicator input and its first and second inputs connected to zero and first inputs of decoder with its first output connected to input "Record" of first memory register. Decoder second output is connected to input "Record" of second memory register. Set inputs of first and second memory registers and those of pulse counter are connected via control pushbutton to bus "Logical unity Voltage". It comprises also second indicator of third and fourth memory registers, second and third OR elements and third and fourth indicators. Data inputs of third and fourth memory registers are connected to ADV outputs while data outputs are connected to computer data inputs. Input "Record" of third memory register is connected with decoder third output. Input "Record" of fourth memory register is connected with decoder fourth output. Set inputs of third and fourth memory registers are connected with set inputs of first and second memory registers. Decoder fourth output is connected to computer "computation" input and to input of second indicator. Decoder second and third outputs are connected to inputs of second OR element. Outputs of first and second OR element are connected to inputs of third OR element with its output connected to third indicator input. Second OR element output is connected to fourth indicator input.

EFFECT: higher accuracy of tightening torque control.

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