Belt Tensioning Instructions - MROSupply

1 belt Tensioning InstructionsTiming BeltHTB, Standard and Metric timing belts should be installed tofit pulleys snugly, neither too tight nor too loose. The belt spositive grip eliminates the need for high initial a belt is installed with a snug but not overly tight fit,longer belt life, less bearing wear and more quiet operationwill result. Overtight belts can cause early failure and shouldbe avoided. With high torque a loose belt may jump teeth upon startup. If such occurs, the tension should be increasedgradually until satisfactory operation is properly tension a timing belt , place belt on pulleys andadjust takeup until the belt teeth mesh securely with the pul-ley grooves.

2 Measure belt span t . Then tighten belt so thatit deflects 1/64-inch for every inch of belt span when a forceas specified in the table below is applied to the top of thebelt. For belts wider than two inches, a metal or woodenstrip 3/4 to 1-inch wide should be placed across the beltbetween it and the tester to prevent following range of deflection forces are normally ade-quate for drive installation. Actual installation tensionrequired depends on peak loads, system rigidity, number ofteeth in mesh, belt Tensioning Deflection Force TableHTB 8MM(8mm)HTB 14MM(14mm)MXL(.080-in.)XL(1/5-in.)L(3/8- in.)H(1/2-in.)XH(7/8-in.)XXH(1-1/4-in.)2 0mm30mm50mm85mm40mm55mm85mm115mm170mm1/8 -inch3/16-inch1/4-inch5/16-inch1/4-inch5 /16-inch3/8-inch1/2-inch3/4-inch1-inch3/ 4-inch1-inch1-1/2-inch2-inch3-inch2-inch 3-inch4-inch2-inch3-inch4-inch5-inch2 to 4 lbs3 to 6 lbs7 to 11 lbs11 to 19 lbs5 to 11 lbs8 to 17 lbs14 to 27 lbs20 to 40 lbs30 to 60 lbs1 oz1 - 1-1/2 oz2 oz2 - 2-1/2 oz2-1/2 oz3 oz3-1/2 oz7 oz11 oz1 lb2 lbs2-1/2 lbs4 lbs5-1/2 lbs8-1/2 lbs7-1/2 lbs11-1/2 lbs16-1/2 lbs9 lbs14 lbs20 lbs26 lbsBelt WidthDeflection ForceBelt PitchMulti-Rib belt Deflection Force Cross SectionSmall SheaveDiameter RangeForce F Lbs.

3 Per ribV- belt & Multi-Rib SeriesV- belt Tensioning adjustment can be made using a tensiongauge or other type spring scale, using the following pro-cedure. After seating the belts in the groove and adjustingcenter distance so as to take up slack in the belts, furtherincrease the tension until only a slight bow on the slackside is apparent while the drive is operating under the drive, and using the gage, measure the force nec-essary to depress one of the center belts 1/64-inch forevery inch of belt span (see sketch below). For example, adeflection for a 50-inch belt span is 50/64ths, or 25/32-inch. The amount of force required to deflect the beltshould compare with the deflection forces noted in thechart below.

4 Also notice for V-belts the deflection forcesvary from the initial run-in values which are greater(reflecting higher run-in Tensioning ) to the normal valuesfor after the run-in the span length t as shown in the sketch V- belt Tensioning DeflectionForce TableBeltCross-SectionAAXBBXCCXDE3V3VX5V 5VX8 VSmaller PulleyDiameter Range(in.) (lbs.)3-3/84-1/45-1/84-1/856467-1/85-1/4 7-1/8911-1/415-3/413-1/217-1/224-1/23348 6778162018223640 Normal(lbs.)2-1/42-7/83-3/82-3/43-1/442- 5/845-1/43-1/24-3/467-1/210-1/2911-3/416 -1/2223245568-1210-1510-1412-1818-2720-3 0 Deflection Force37 belt Tensioning InstructionsSpan LengthtDeflection 1/64 per inch of spanForce at center ofspanSee Pg 7 for Tiger ValuesInsides:JB-7 Broc.

5 Revise 8/16/05 6/20/07 8:48 AM Page 35