| 摘要 |
1,173,202. Boring earth &c. BYRON JACKSON Inc. 7 Feb., 1967 [21 Feb., 1966], No. 5723/67. Heading E1F. A drill pipe protector P rotatable on a drill string S comprises similar rubber parts 2 each having metal reinforcing 4 with flanges 6, 7 and bolts 10 engaging threaded holes in bars 12 holding the parts together. The bars are bonded to the parts and the holes receiving the heads of the bolts prevent accidental disengagement of the bolts from the parts. |
