What is an elevator bucket bolt?
An elevator bucket bolt is a special bolt for fixing buckets to the elevator belt. Its head is wide, flat and slightly concave; teeth or lugs under the head bite into the belt when tightened and stop the bolt turning. The nut is tightened from the bucket side.
Why standard bolts should not be used
- Protruding head: a standard bolt head sticks out of the belt; as the belt passes over the pulley it rubs, wearing both belt and pulley.
- Load spread: a small head concentrates load on a small area and tears the belt hole.
- Turning: with nothing to stop it turning, the bolt spins in the belt while tightening and the right torque cannot be applied.
Correct fitting
- Insert the bolt from the inner (pulley) side of the belt; the head should be flush with the belt surface.
- Fit the bucket and, if needed, a washer, then tighten the nut from the bucket side.
- Tighten until the bolt head is fully seated in the belt, but without crushing or piercing the belt.
- Locking nuts (nylon-insert or serrated) are recommended against loosening.
Checking for loosening
After first start-up the belt beds in a little and bolts can loosen. Check them during the first days and periodically afterwards. A loose bolt can make a bucket wobble or tear off and damage the elevator casing. Renewing bolts when replacing buckets is good practice.
