Square Drive Roller Kelly Bushings

The Square Drive Roller Kelly Bushing provides the following advantages:

. Pulling out or feeding off string can be done while rotating;
. Because of its integral construcation, it can not fly out and hurrts you.
. The bushing is easily installed into the master bushing, maintaining good alignment;

. The contact between Kelly and roller is rolling contact, so friction is lower, and weight on bit is accurate;
. The Kelly has lower wear and has long life;
. Lobor condition is improved, and penetration rate is faster. The roller bushings made in our company with cover type. Its bottom seat of the Kelly bushing with cover is made up of cover and lower seat. There is rolling bearing between roller and roller pin.