The Roller Kelly Bushing is an essential drilling tool, can be equipped with turntable slips, so as to drive Kelly bar. The tool reduces its friction with Kelly bar by the rolling of four rollers in order to prolong its life. As for the square or hexagon Kelly bar, they connect with all kinds of turntables by changing roller, with two drive methods, namely, square rolling and pin shaft rolling. The Roller Kelly Bushing is simple in operation, convenient in installation and perfect in safety performance. It can be applied to rotary table from 17 1/2" to 49 1/2".

Construction

The Roller Kelly Bushing consists of top cover, base, axis, needle bearing, sealing body, roller, binding bolt, and refuel cup. The needle bearing within the roller is being installed on axis which both ends compact between top cover and base. There is interval 3mm between top cover and base, in order to give full play to pressing force formed by four big kingbolts M38. The refuel cup  lying on axis end injects grease into needle bearing at regular intervals. In order to prevent the sealing body from penetrating and protect the needle bearing, the inner-outer O type circle must be installed on the both ends of the roller. Fasten pin lying on the top of sealing body prevents it from rotating,and inlays inside seam allowance of up base.

Kelly Size		Elevation (mm)		Bedplate Size (mm)		Tapering
(in)	(mm)	Top	Lower	Opposite Side	Large End
3 1/2	88.9	406	356	332	φ332	1:3
4 1/4	107.95
5 1/4	133.35