Force measuring unit and system for measuring chain forces

A force measuring unit for measuring a force applied to an individual chain link of a chain strand used in underground mining applications, the chain strand including a plurality of chain links engaging each other, each chain link of the plurality of chain links having a first chain link leg and a second chain link leg opposite to the first chain link leg, the force measuring unit comprising:

• a housing having a first end configured to be contacted by the first chain link leg and a second end configured to be contacted by the second chain link leg, the housing being elastically deformable such that a distance variation between the first chain link leg and the second chain link leg is possible;
• a distance measuring device accommodated within the housing and configured to measure an actual distance between the first chain link leg and the second chain link leg, the distance measuring device including a first unit part configured to be contacted by the first chain link leg and a second unit part configured to be contacted by the second chain link leg;
• a magnet provided at the first unit part;
• and
• a magnetic field sensor provided at the second unit part and configured to detect a magnetic field caused by the magnet,
• wherein, due to the distance variation between the first chain link leg and the second chain link leg caused by the force applied to the chain strand, the first unit part and the second unit part move relative to each other, such that the actual distance between the first and second chain link legs can be measured, and
• wherein, due to the relative movement between the first unit part and the second unit part, the magnet moves relative to the magnetic field sensor causing a variation of the detected magnetic field.