Patent ID: 8127836

Claim:
A top drive for engagement with a travelling block with a hook, the top drive comprising: a. an airlift thread compensator comprising a bail for engaging the travelling block with a hook and an airlift enclosure connected to the bail, wherein the airlift enclosure comprises: (i) a first enclosure side comprising a first pin slot; (ii) a second enclosure side comprising a second pin slot, wherein a rear enclosure side is connected to the first enclosure side and the second enclosure side; (iii) a bail pin extending from the first enclosure side to the second enclosure side, wherein the bail pin is movably engaged within the first pin slot and the second pin slot; and (iv) an airbag with an inflator valve disposed within the airlift enclosure, wherein the airbag is connected to the bail pin, wherein an airlift enclosure bottom is connected to the rear enclosure side, to the first enclosure side, and to the second enclosure side, wherein the airbag is connected to the airlift enclosure bottom, wherein a top enclosure side is connected to the rear enclosure side opposite the airlift enclosure bottom, and wherein the bail pin extends beneath the top enclosure side within the airlift enclosure; b. a first upper link and a second upper link, each connected to the bail pin; c. a top drive housing connected to the first upper link and to the second upper link, wherein the top drive housing supports a rotatable stem; d. a motor splinably connected to the rotatable stem and mounted to the top drive housing; e. a heavy thrust bearing disposed about the rotatable stem; f. a first lower link and a second lower link, each connected to the top drive housing; g. an inside blow out preventer connected to the rotatable stem; h. a saver sub connected to the inside blow out preventer; i. a torque wrench assembly connected to the top drive housing; and j. an elevator connected to the first lower link and to the second lower link.