Patent ID: 7976242
Filing Date: 2011-07-12
Classification: E21B

Abstract:
1. A drill head comprising: a drill head main body including a front end and a back end, the back end configured to be connected to a drill rod, the drill head main body including a rear outer shell having a first end positioned at the back end of the drill head main body and a second end positioned at an intermediate location between the front and back ends of the drill head main body, the drill head main body also including a rear end plate mounted to the first end of the rear outer shell and a support structure mounted to the second end of the rear outer shell, the support structure extending forwardly from the second end of the rear outer shell; a shaft bearing mounted to the support structure; a drive shaft that extends through the drill head main body generally from the rear end plate to the front end of the drill head main body, the drive shaft having a front end adapted for connection to a cutting unit, the drive shaft being rotatably supported within the support structure by the shaft bearing; a steering shell mounted over the support structure; and a steering shell driving arrangement incorporated into the support structure for generating relative radial movement between the steering shell and the support structure.