Dynamic diameter measurement device for downhole wireline cables

A diameter measurement device disposed on a wireline downhole cable handling device for measuring the diameter of a wireline cable dynamically during moving the cable in or out of a borehole, comprising:

• a first pair of opposed shafts,
• a first resilient member mounted to urge at least one of the shafts of said first pair of opposed shafts toward the wireline cable to be measured,
• a first intrinsic measuring unit including an electronic sensor for measuring at least one intrinsic property, taken from the group of impedance and magnetism, that varies with the amount of displacement of said first resilient member and is operatively associated with the first resilient member to measure the displacement thereof and output an electronic signal correlating to said displacement,
• at least a second pair of opposed shafts angularly displaced with respect to the first pair of opposed shafts,
• a rotating roller on each shaft of said second pair of opposed shafts,
• a second resilient member mounted to urge at least one of the shafts of said second pair of opposed shafts toward the wireline cable to be measured,
• a second intrinsic measuring unit including an electronic sensor for measuring at least one intrinsic property, taken from the group of impedance and magnetism, that varies with the amount of displacement of said first resilient member and is operatively associated with the first resilient member to measure the displacement thereof and output an electronic signal correlating to said displacement as the wireline cable is moved lengthwise between the rollers;
• wherein each of said first and second intrinsic measuring devices outputs said electronic signals to a digitizer for generating digital measurements of the diameter at various positions on the circumference of and along the length of said wireline cable, which measurements are transmitted to and stored in a logging device.