Patent ID: 8127836
Filing Date: 2012-03-06
Classification: E21B

Abstract:
1. 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: 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.