Bolt Type Force Sensor with Improved Wiring for Force Measurement in Sport Climbing

This paper proposes a new bolt type force sensor that can be used as a bolt to fix an object and can also measure the force applied to the fixed object. The intended application of this sensor is force measurement in sport climbing. Climbing holds are generally fixed by a steel bolt. Four strain gauges are installed to the shaft of the bolt to detect forces applied during sport climbing. This proposed sensor allows force measurement without the need to modify climbing holds or distance them from the wall to install force sensors. Additionally, the wiring comes out from the threaded side of the bolt, and when installed, the wiring comes out from behind the wall. Therefore, it does not interfere with the movement of sport climbing. In this paper, the structure of the sensor is firstly introduced. Next, the calibration method using 6-axis force sensor is shown. Finally, force measurement experiments are conducted, and it is confirmed that the sensor is able to achieve force estimation in practical situations.