Elastic ring length-measuring device

The invention relates to an elastic ring length-measuring device which comprises a frame, a detection apparatus, a force supplying apparatus and a controller, wherein the frame comprises a first crossbeam, a second crossbeam and a first fixing column and a second fixing column arranged between the first crossbeam and the second crossbeam, the detection apparatus comprises a linear sliding resistor and a sliding resistor adjusting column, which slides back and forth along the linear sliding resistor to adjust the output resistance between the starting end of the linear sliding resistor and the sliding resistor adjusting column, the force supplying apparatus pulls the sliding resistor adjusting column towards the second fixing column with preset pulling force, and the controller converts the output resistance value into length value. The force-bearing deformation of an elastic ring is converted into electric signals, which is then converted into the length of the elastic ring after deformation, thereby avoiding