Dear Ganesh,

1) For plied fabric belts your equation of (n-1)x100/n is a starting point but the belt will never reach that level.

In a straight pull test there is a stress concentration that occurs in the outer plies reducing the theoretical strength below this level. When you start looking at the stresses in the splice going around pulleys the theoretical splice strength continues to decrease.

2) If you search the forum I expect this question has already been addressed. It's related to the number of steps in the splice and the splice design.

3) If you are using a properly done finger splice the efficiency can be very high. > 90%. If your using a butt or overlap style splice the efficiency, going around pulleys, is much lower.

Best regards,

Andrew Hustrulid

Originally Posted by sganesh

Dear experts,

In the multiple ply fabric belts, the theoretical joint efficiency is (n-1)x100/n where n is the number of plies present in the fabric belt. For example, in 5 belt, the joint efficiency is 80%, for 4 ply belt, it is 75% and so on.

Kindly clear my doubts :

1) Is this same for cold joint also?

2 ) How the joint efficiency is calculated in steelcord conveyor belts ?

3) How is this calculated for single ply conveyor belts ?

Thanks & Regards,

■

Originally Posted by ahustrulid

Dear Ganesh,

1) For plied fabric belts your equation of (n-1)x100/n is a starting point but the belt will never reach that level.

In a straight pull test there is a stress concentration that occurs in the outer plies reducing the theoretical strength below this level. When you start looking at the stresses in the splice going around pulleys the theoretical splice strength continues to decrease.

2) If you search the forum I expect this question has already been addressed. It's related to the number of steps in the splice and the splice design.

3) If you are using a properly done finger splice the efficiency can be very high. > 90%. If your using a butt or overlap style splice the efficiency, going around pulleys, is much lower.

Best regards,

Andrew Hustrulid

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In principle, I agree with Andrew with some caveats:

1. Fabric belt splice endurance strength will be greatest with Finger Splice - however, the depth (belt thickness) must be considered when analyzing the endurance. We assume the finger geometry is more or less the same for any splice. There is little effort in defining less than is typical.

2. There are overlap or ply splices that enhance the strength of each beyond the typical step length.

3. There are reinforcement techniques that enhance the splice endurance by overlapping the step with a second fabric on the outer steps. This will increase the belt thickness. There is a trade-off between allowing a local thicker belt and losing a step. ■