Driver Pulley Follower Pulley

Compound belt drives

1

2

3

4

A compound belt drive is used when power is transmitted from one shaft to another through a number of pulleys.

1

2

3 4

Slip and creep in belt dives

Tight side

Slack side

Slip

The firm grip between the pulley and the belt is obtained by friction

This firm grip is known as frictional grip

But some times, the frictional grip becomes in sufficient. This may cause some forward motion of the pulley without carrying the belt with it. This is called as slip of the belt and is generally expressed in percentage.

Tight side

Slack side

Creep

When the belt passes from slack side to tight side, a certain portion of the belt extends and contracts again when the belt passes from tight side to slack side.

Due to these changes, there is a relative motion between the belt and pulley surfaces. This relative motion is termed as creep

22 1

1 2 1

EN d

N d E

1 2, s inStres the belt driveon tight and slack side respectively

E – Young’s modulus of belt material