Improvements in or relating to rotary draw works for well drilling plant
311,699. Emsco Derrick & Equipment Co., (Assignees of Goeser, E. W.). May 14, 1928, [Convention date]. Borehole apparatus.-In the rotary draw works of a well-drilling plant, a line shaft 25, through a clutch 41 and chain 75, drives a sleeve 72 from which the rotary table is driven through a chain 81; the sleeve 72 rotates on a shaft 46, the flattened ends of which rest on plates 62 and shims 63, caps 65, with eccentric bores, holding the shaft 46. By removing some of the shims 63, the chain 75 may be tightened, while reversing the caps 65, the chain 81 may be tightened. The line shaft 25 may also drive a hoisting drum at either of three speeds through sprockets 22, 23, 24, and clutches on the drum shaft.