Patent ID: 8997893
Filing Date: 2015-04-07
Classification: E21B

Abstract:
1. A multi-ram drill rig comprising: a drill tower; a drill head capable of applying torque to a drill bit, the drill head supported on the drill tower for linear motion along the drill tower; a travelling sheave trolley supported on the drill tower for linear motion along the drill tower and coupled to the drill head wherein a force applied in one direction to the travelling sheave trolley is transferred as a force acting in an opposite direction to the drill head; and, a plurality of rams coupled between the tower and the travelling sheave trolley, the rams being selectively actuated to apply a selectively variable force symmetrically to the travelling sheave trolley in either direction along the drill tower, wherein the selectively variable force is transferred by the travelling sheave trolley to the drill head to apply hold back and pull down to a drill bit coupled to the drill head.