|The Square Drive Roller kelly Bushing provides the following advantages;
1. Pulling out or feeding off string can be done while rotating;
2. Because of its integral construction it can not fly out and hurts you.
3. The bushing is easily installed into the master bushing maintaining good alignment
4. The contact between kelly and roller is rolling contact so friction is lower an weight on bit is accurate;
5. The kelly has lower wear and has long life;
6. Labor condition is improved,and penetration rate is fast;
The roller bushings made in our company have two types: with cover type and without cover type.
The bottom seat of the kelly bushing with cover is made up of cover and lower seat.
There is meedle bearing between roller and roller pin.
The bottom seat of the kelly bushing without cover is integral. Roller is connected with roller pin through sliding bearing.The size is smaller and the weight is lighter than the one of the bushing with cover.