| 摘要 |
A kelly driver has a top ring and a plurality of split bushings. The a top ring has a top surface, a bottom surface, a drive lug extending from the bottom surface, and a central passage extending through the top and bottom surfaces. The drive lug has a notch within an end face thereof. A first one of the split bushings has a drive lug extending outwardly from a side surface thereof. Adjacent pairs of the split bushings have end portions thereof pivotably connected to each other through a respective hinge structure. Each hinge structure includes a respective connection pin about which adjacent pair of the split bushings are pivotably connected. An upper surface of each one of the split bushings is engaged with the bottom surface of the top ring with the drive lug of the first one of the split bushings positioned within the drive lug of the top ring.
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