| 摘要 |
A friction reducing tool for drilling applications having a plurality of rollers for about the periphery of the tool (3). The rollers (4) have extensions (7) which locate within cavities (8) to prevent the rollers from passing from cavity (10) to the exterior of the tool. The tool is formed in multiple parts (3a and 3b) having interengaging tongues (5 and 6) which are joined together by passing a rod (15) through bore (13). A groove (14) is provided in outer component (2) to enable rod (15) to be inserted in bore (13).
|
