| Patent application number | Description | Published |
|---|
| 20100307832 | TRACTOR WITH IMPROVED VALVE SYSTEM - A hydraulically powered tractor adapted for advancement through a borehole including an elongate body, aft and forward gripper assemblies, and a valve control assembly housed within the elongate body. The aft and forward gripper assemblies are adapted for selective engagement with the inner surface of the borehole. The valve control assembly includes a gripper control valve for directing pressurized fluid to the aft and forward gripper assemblies. The valve control assembly also includes a propulsion control valve for directing fluid to an aft or forward power chamber for advancing the body relative to the actuated gripper assembly. Aft and forward mechanically actuated valves may be provided for controlling the position of the gripper control valve by detecting and signaling when the body has completed an advancement stroke relative to an actuated gripper assembly. Aft and forward sequence valves may be provided for controlling the propulsion control valve by detecting when the gripper assemblies become fully actuated. Furthermore, a pressure relief valve is preferably provided along an input supply line for limiting the pressure of the fluid entering the valve control assembly. | 12-09-2010 |
| 20100314131 | VARIABLE LINKAGE ASSISTED GRIPPER - A gripper mechanism for downhole tool is disclosed that includes a linkage mechanism and a flexible toe disposed over the linkage mechanism. In operation, an axial force generated by a power section of the gripper expands the linkage mechanism, which applies a radial expansion force to the flexible toe. For certain expansion diameters, the expansion force can be primarily transmitted to the toe from a roller-ramp interface expanding the linkage. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a three-bar linkage configuration. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a four-bar linkage configuration. Thus, the gripper can provide a desired expansion force over a large range of expansion diameters. | 12-16-2010 |
| 20110042100 | WELLBORE CIRCULATION ASSEMBLY - In some embodiments, a circulation assembly can direct all or substantially all fluid downstream in a drill string in a first mode of operation, and some or all fluid to an annulus in a second mode. Operation of the circulation assembly can be repeatedly changed between the modes of operation. In some embodiments, the circulation assembly can comprise other modes wherein fluid is apportioned between the annulus and the downstream drill string. | 02-24-2011 |
