2.6 Preventive Maintenance Procedures for Chain Drives

When it comes to inspections, risk of failures for not  following the procedures below is noted along with a rating: 

  • Low: Minimal risk or low chance of failure.
  • Medium: Failure is possible, but equipment not operating to specification is highly probable.
  • High: Failure will happen prematurely. 

Here are some inspection procedures: 

1. Inspect a chain for wear by inspecting the links for worn bushings. If worn bushings are noted, write a corrective maintenance work order so that the replacement can be planned and scheduled at a later time. 

  • Risk if the procedure is not followed: High; chain breakage will occur. 

2. Lubricate chain with lightweight oil recommended by the chain manufacturer. Ask your chain supplier to visit your site and make recommendations based on documentation they can present to you. 

  • Risk if the procedure is not followed: High; chain breakage will occur. 

3. Check chain sag. Measure the chain sag using a straight edge or string, and measure the specifications noted on the preventive maintenance task. 

4. Set tension, and make a note at the bottom of the preventive maintenance work order, if a deficiency is noted. 

  • Risk if the procedure is not followed: Medium; sprocket and chain wear will accelerate, thus causing equipment stoppage. 

5. Inspect sprockets for worn teeth and abnormal wear on the sides of the sprockets. Ask yourself, “Can the sprockets and the chain last for two more weeks without equipment stoppage?” If the sprockets and chain can last two weeks, then write a corrective maintenance work order in order for this job to be planned and scheduled with the correct parts. If the sprocket can not last two weeks, then change all sprockets and the chain. Set and check sheave and chain alignment and tension. 

Warning: When changing a sprocket, all sprockets and the chain should be changed, because the difference between a worn and new sprocket in pitch diameter can be extreme; thus, causing premature failure of the sprockets and chain. 

  • Risk if the procedure is not followed: High; work sprockets are an indication of the equipment being in a failure mode. Action must be taken.