Development of prototype machine brake and car safety gear testers for traction lift systems

Abstract

Machine brakes and safety gears of traction lifts are two critical components of the biggest safety concerns, as the main braking system and redundant fail-safe mechanism respectively stop and hold lift cars from unintended car movement, overspeed or under a free-fall condition during emergency. There are challenges of routine maintenance on how to continually verify the effectiveness of them to mitigate risk potentials of equipment failure. This pilot study intends to design, implement and test low-cost, non-intrusive and on-line prototype testers with the aid of sensors for real-time monitoring of critical parameters of these safety devices. Critical parameters that are measurable include real-time variations of brake lining temperature, brake solenoid current, vibrational patterns of brake arms and lift car, position of lift car, and the actuating status of safety gears. Critical parameters after processing include a newly defined energy of brake arm operation and estimated deceleration rate of a fully loaded car by safety gears operation on an unloaded car. Early signs of abnormalities of these two safety devices can be detected before they fail. Additionally, the prototype testers can facilitate more frequent unloaded full-speed testing of safety gears to verify the effectiveness. The proof-of-concept prototype could be a quick monitoring alternative to existing and new traction lift systems.