Thread connection is widely used in mechanical connection. Torque wrench can feedback tightening torque in real time, and can apply more accurate tightening torque, which is widely used in engineering. Some assembly lines in aerospace or military field the tightening accuracy need to reach 0.1%, comparing with the only 1% accuracy of ordinary working wrench, the high precision torque wrench is needed to apply the high accuracy torque in aerospace or military field. Two methods are introduced to improve the measurement accuracy of the torque wrench. One is to design the transducer with pure torsional transformation when it is used. The other is to apply linearity correction to the transducer by circuit software. The results shows the accuracy of the torque wrench is 0.1%, which is much higher than ordinary work wrench.
A method by using strain-gauged transducer to adjust the alignment of the materials testing machine is introduced in this paper. In order to improve the accuracy of the material test, the alignment of the material testing machine should be adjusted before tests. A transducer with three levels of strain gauges is applied before the specimens are tested. By calculating the bending stress according to the equation in ASTME1012,an adjustment suggestion to reduce the angular misalignment and concentric misalignment is given by the calculation results. Through adjusting the direction and position of the grips until the value of the strain gauges meet the requirement, the misalignment of the material testing machine will be removed.
In large assembly workshop, such as automobile assembly workshop, the number of the wrenches is large. Some wrenches that used in fields are scattered. It is not convenient to send all such wrenches to laboratory for calibration at the same time, so it is necessary to develop a torque wrench calibration device which is suitable for on-site calibration. An intelligent indicator with MCU was developed, which can display and record the torque value, which is convenient for operators to record the data without paper and can check the data later. The intelligent indicator can also calculate the error at the same time, which improves the work efficiency by replacing manual calculation. A DS2401 chip was hidden in the transducer. It is cheap and has an unique sequence code, which is easy to identified by MCU. The MCU seeks the codes already stored in the indicator and matches linear correction coefficient to the transducer. It is first to use DS2401 chip to realize plug and play, which can avoid the measurement error even device damage caused forgetting switch the channel. The device also has an chargeable motor, which can save time and labor especially when mechanical gap exists and load a large torque value. The main characters of the device are auto-identifying transducer, powerful data handling similar to a compute and chargeable motor. All of these guarantee the device being intelligent and efficiency for the on-site wrench calibration.
Currently, the vast majority of sensor applied in the field of dynamic testing is piezoelectric sensor, Piezoelectric sensors over 200t are very difficult to produce, However, the traditional strain sensor is not suitable for dynamic testing due to its insufficient frequency response, The large-range strain type dynamic three-component force sensor developed in this paper has been successfully applied in high-speed rail collision test experiment, which breaks the monopoly of piezoelectric sensor in the field of dynamic test and has a broad application prospect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.