A gear feed system includes a carrier and a mast mounted on the carrier. The mast includes a pair of panels forming opposing sides of the mast along a central axis of the mast. Each of the pair of panels includes a fixed rack attached to an interior surface of the each of the panels. A gear carrier pair includes a gear, a movable rack assembly, and a cylinder. Each of the gear is coupled to one of the panels and each of the gear couples one of the fixed racks to one of the movable rack assemblies (hoist tubes). The cylinder and the movable rack assembly are coupled via the gear wherein an axial movement of the cylinders causes a corresponding axial displacement of the movable rack assemblies.

A gear feed system includes a carrier and a mast mounted on the carrier. The mast includes a pair of panels forming opposing sides of the mast along a central axis of the mast. Each of the pair of panels includes a fixed rack attached to an interior surface of the each of the panels. A gear carrier pair includes a gear, a movable rack assembly, and a cylinder. Each of the gear is coupled to one of the panels and each of the gear couples one of the fixed racks to one of the movable rack assemblies (hoist tubes). The cylinder and the movable rack assembly are coupled via the gear wherein an axial movement of the cylinders causes a corresponding axial displacement of the movable rack assemblies.

A controllable drilling head for a drill string for ground drilling with a drilling head tip and a locating pin that carries the drilling head tip, the drilling head tip having a bore slanted to the longitudinal axis and the locating pin being angled to the longitudinal axis, wherein the drilling head tip can rotate on the locating pin, the drilling head tip and the locating pin being arranged in a first angular position relative to one another for straight drilling, and the drilling head tip and the locating pin being arranged in a second angular position relative to one another for drilling that deviates from straight drilling.

A controllable drilling head for a drill string for ground drilling with a drilling head tip and a locating pin that carries the drilling head tip, the drilling head tip having a bore slanted to the longitudinal axis and the locating pin being angled to the longitudinal axis, wherein the drilling head tip can rotate on the locating pin, the drilling head tip and the locating pin being arranged in a first angular position relative to one another for straight drilling, and the drilling head tip and the locating pin being arranged in a second angular position relative to one another for drilling that deviates from straight drilling.

A modular boost system can be added to a jack to enable greater lift capacity of the jack. One example can involve a jack that is positionable at a well surface for moving a tubing string through a wellbore in a subterranean formation. The jack can include a frame and an adjustable plate that is alternately (i) attachable at a stationary location in the frame for fixing the adjustable plate at the stationary location or (ii) detachable from the stationary location in the frame to enable the adjustable plate to vertically move within the frame. A boost cylinder can be removably coupled to the adjustable plate and a base for selectively supplying an additional lift capability to the jack.

A modular boost system can be added to a jack to enable greater lift capacity of the jack. One example can involve a jack that is positionable at a well surface for moving a tubing string through a wellbore in a subterranean formation. The jack can include a frame and an adjustable plate that is alternately (i) attachable at a stationary location in the frame for fixing the adjustable plate at the stationary location or (ii) detachable from the stationary location in the frame to enable the adjustable plate to vertically move within the frame. A boost cylinder can be removably coupled to the adjustable plate and a base for selectively supplying an additional lift capability to the jack.

A stall control system for a raise boring machine is provided. In one implementation, the stall control system includes one or more hydraulic control valves connected to thrust cylinders of the raise boring machine to vent pressurize oil from a cap end of the thrust cylinders back to an oil tank or to a rod end of the thrust cylinders. In another implementation, the stall control system includes one or more hydraulic control valves connected to thrust cylinders of the raise boring machine to inject pressurized oil into a rod end of the thrust cylinders to increase pressure on the rod end of the thrust cylinders.

An automated pipe tripping apparatus includes an outer frame and an inner frame. The inner frame includes a tripping slips and iron roughneck. The automated pipe tripping apparatus may, in concert with an elevator and drawworks, trip in a tubular string in a continuous motion. The tripping slips and iron roughneck, along with the inner frame, may travel vertically within the outer frame. The weight of the tubular string is transferred between the tripping slips and the elevator. The iron roughneck may make up or break out threaded connections between tubular segments, the upper tubular segment supported by the elevator and the lower by the tripping slips. An automated pipe handling apparatus may remove or supply sections of pipe from or to the elevator. A control system may control both the automated pipe tripping apparatus and the elevator and drawworks.

An automated pipe tripping apparatus includes an outer frame and an inner frame. The inner frame includes a tripping slips and iron roughneck. The automated pipe tripping apparatus may, in concert with an elevator and drawworks, trip in a tubular string in a continuous motion. The tripping slips and iron roughneck, along with the inner frame, may travel vertically within the outer frame. The weight of the tubular string is transferred between the tripping slips and the elevator. The iron roughneck may make up or break out threaded connections between tubular segments, the upper tubular segment supported by the elevator and the lower by the tripping slips. An automated pipe handling apparatus may remove or supply sections of pipe from or to the elevator. A control system may control both the automated pipe tripping apparatus and the elevator and drawworks.

The present invention is a rod jack apparatus with four vertical legs that form a framework and first and second lower brackets connected to the vertical legs. Two hydraulic cylinders extend upwardly from the lower brackets, pass through a first horizontal plate, and are connected to a second horizontal plate. A primary clamping mechanism is situated on top of each of the two horizontal plates, and a secondary clamping mechanism is attached to the underside of each horizontal plate. The apparatus is configured to receive a polished rod, and the primary and secondary clamping mechanisms are configured to grip the polished rod when activated. The sucker rod assembly is lifted out of the well when the first and second hydraulic cylinders are extended. The invention includes a method of using the apparatus described herein.