Chain Wear Indicator

grabcad

This is my idea for a cheap, simple and reliable chain wear indicator for electric chain hoists. (Short version at the bottom) Long version --- The system consists of two parts: 1. The control system This is the main part to detect and warn of chain failure. The system consists of: -Rotation encoder/Motor controller interface -Two "Lasers" (directed light, like in a laser pointer -Two light sensors -Basic microcontoller -Warning hardware (eg. lights or hoist interface) 2. The clips The can be attached to the chain at even intervals (eg. every 5th link). They consist of: -Two identical plastic clips (matching the chain size) -A "corrosion fuse" (an extremely corrosive thin piece of metal) The system works as follows: The plastic clips are mounted (with corrosion fuses) at even intervals on the chain. The laser, sensor and controller assembly in mounted internally at the entrance to the hoist or externally as an accessory. The two lasers are kept on, aligned with the holes where the clips come past. The microcontroller reads how much the chain should be moving using the encoder. Using the first sensor (E1) it checks when the opening in the clip comes past (this opening has a fixed width). In software it measures the relationship between the motor movement and real chain length. The microcontroller detects a change between the original relationship of data received from the encoder and data from clip distance measurement and the new data. The controller will then warn the user and/or stop the hoist. Upon installation of a new chain the controller will calibrate itself, meaning any chain can be used. Additionally the controller will check for corrosion by seeing if light is let though the corrosion fuses when the clips come past. If the links have been in a corrosive environment this "fuse" will corrode much earlier and break, letting light come through. This is an early warning system and has the advantage of measuring corrosive conditions the specific links were exposed to and not in the general environment. If any chain stretch or corrosion is found, the controller will warn the user and disable the hoist. The whole system is very simple and cost effective to manufacture and install. It requires no modification of the chain and could possibly be made as an external accessory for existing hoists. Deformation can be detected on the fly as long as two clips pass through the controller assembly. The controller can easily be calibrated to a new chain by pulling the chain though and gathering data. The clips can be reused for a new chain. More clips can be added for better accuracy. Short version --- -Clips are placed at even distances -Encoder measures motor movement -Laser S1/E1 measures clip separation and movement -Change in encoder data to clip separation data ratio will stop the hoist -Corrosion is detected by checking for light coming through the corrosion fuse (S2/E2) Thanks for looking at my idea and I hope you all liked it