industrial belt and drive preventive maintenance - Gates Corporation

IV. Drive shutdown and thorough inspectionWhen rotating drives by hand to ensure correct tracking of thebelt, care must be taken not to trap fingers between the beltand pulley. Rotation of large synchronous drives by pulling onthe belt is particularly hazardous where entrapment of fingersbetween pulley flanges and the belt can result in immediateamputation of the finger(s).Use a straight edge to check pulley alignment.LASER AT-1 laser alignment device3. Pulley inspectionIf belts have been removed from the drive, check pulleys forunusual wear or obvious signs of damage. Wear is not alwaysobvious. Use Gates sheave gauges to check V-grooves. Forsynchronous belt drives, check the pulley diameters over thewidth of the pulley to ensure they are consistent and meet ourtolerances (see Gates Drive Design Manual E2/20099).Always check pulleys for proper alignment and mounting.Improperly aligned pulleys result in reduced service life.The main causes of misalignment are:• pulleys are improperly located on the shafts;• motor shafts and driven machine shafts are not parallel;• pulleys are tilted due to improper mounting.The LASER AT-1 identifiesparallel as well as angularmisalignment between thepulleys and is suitable forpulley diameters of 60 mmand larger. Mounted in afew seconds, the laser lineprojected on the targets allowsyou to quickly ascertain andcorrect misalignment. It can be used on both horizontally andvertically mounted machines. For more information please seeleaflet E2/20121.Forms of misalignmentParallel misaligmentAngular misaligmentFleeting angle*Fleeting angle*4. Check alignment tolerancesAs a general rule, the deviation on pulley alignmenton V-belt drives should not exceed 1/2° or 5 mm per500 mm of drive centre distance. Alignment for synchronous,Polyflex® and Micro-V® belts should be controlled within 1/4°or 2.5 mm per 500 mm of drive centre distance.The greater the misalignment, the greater the chance of beltinstability, increased belt wear and V-belt turnover.* Refer to "4. Check alignment tolerances".To check alignment, you will need a straight edge or, for longcentre distance drives, heavy string. Line the straight edge orstring along a machined face of both pulleys as shown on thepicture below. Misalignment will show up as a gap betweenthe face of the pulley and the straight edge or string. Whenusing this method, make sure the distance between thegroove edge and the outer rim of both pulleys is identical.Pulleys can also be checked for tilting with a spirit level.Max deviation of Per 500 mm of drive centre distancepulley alignment(°) (mm)V-belt 1/2 5Polyflex® 1/4 2.5Micro-V® 1/4 2.5Synchronous belts 1/4 2.55. Check other drive componentsAlways examine bearings for proper alignment and lubrication.Also check motor mounts for correct tightness. Be sure takeuprails are free of debris, obstructions, dirt or rust.6