A ground drilling device comprising a housing, a lengthwise movable drilling head tip arranged in the housing, and a bearing for supporting the drilling head tip in the housing during its lengthwise movement.

The subject disclosure provides for a mechanism implemented with neural networks through machine learning to predict wear and relative performance metrics for performing repairs on drill bits in a next repair cycle, which can improve decision making by drill bit repair model engines, drill bit design, and help reduce the cost of drill bit repairs. The machine learning mechanism includes obtaining drill bit data from different data sources and integrating the drill bit data from each of the data sources into an integrated dataset. The integrated dataset is pre-processed to filter out outliers. The filtered dataset is applied to a neural network to build a machine learning based model and extract features that indicate significant parameters affecting wear. A repair type prediction is determined with the applied machine learning based model and is provided as a signal for facilitating a drill bit operation on a cutter of the drill bit.

A bidirectional cluster hammer reamer (BCHR) for use in a horizontal direction drilling system comprises a plurality of percussive hammers and bits arranged around a central drive rod. The central drive rod is translatable between a forward most position and a rear most position. The central drive rod is translated to the forward most position when the BCHR is being pulled through a previously drilled pilot channel. The central drive rod is translated to the rear most position when a reverse feed force is applied to the BCHR. When in the rear most position, the central drive rod cooperates with an air distribution assembly at the rear of the BCHR to expel a portion of a pressurized fluid to the exterior of the BCHR for clearing accreted debris.

Methods of forming a stationary housing of a rotatable cutting element for use on an earth-boring tool may include forming one or more annular recesses extending around an outer surface of a first sleeve, inserting the first sleeve within a second sleeve, joining the first sleeve with the second sleeve, and removing a portion of material from an inner surface of the first sleeve to expose the annular recesses. Methods may also include forming a first portion and a second portion of a sleeve, forming an annular recess around an entire perimeter of an inner surface of each of the first portion and the second portion of the sleeve proximate a longitudinal end thereof, and bonding the longitudinal ends of the first portion and the second portion of the sleeve along an interface therebetween. Stationary housings formed from such methods are also provided.

Methods of forming a stationary housing of a rotatable cutting element for use on an earth-boring tool may include forming one or more annular recesses extending around an outer surface of a first sleeve, inserting the first sleeve within a second sleeve, joining the first sleeve with the second sleeve, and removing a portion of material from an inner surface of the first sleeve to expose the annular recesses. Methods may also include forming a first portion and a second portion of a sleeve, forming an annular recess around an entire perimeter of an inner surface of each of the first portion and the second portion of the sleeve proximate a longitudinal end thereof, and bonding the longitudinal ends of the first portion and the second portion of the sleeve along an interface therebetween. Stationary housings formed from such methods are also provided.

A bit retention system for a hammer drill including a housing (41), a drive sub (44) connected to lower end of the housing, and a bit retainer (50) having an upper end suspendable from a shoulder of the drive sub and a lower end including a radially inwardly projecting bit retention rim (52). The upper end of a locking sleeve (70) has internal features (78) that are engageable with external features (76) at the lower end of the housing to prevent relative rotation, and a lower end sized (82) to overlap the upper end (90) of the retainer. The lower end of the locking sleeve is welded to the retainer, thus locking the threads on the drive sub from unscrewing from housing threads. The drive sub and retaining member are pinned together to stop separate rotation.

A bit retention system for a hammer drill including a housing (41), a drive sub (44) connected to lower end of the housing, and a bit retainer (50) having an upper end suspendable from a shoulder of the drive sub and a lower end including a radially inwardly projecting bit retention rim (52). The upper end of a locking sleeve (70) has internal features (78) that are engageable with external features (76) at the lower end of the housing to prevent relative rotation, and a lower end sized (82) to overlap the upper end (90) of the retainer. The lower end of the locking sleeve is welded to the retainer, thus locking the threads on the drive sub from unscrewing from housing threads. The drive sub and retaining member are pinned together to stop separate rotation.

Hydraulic pulses are produced each time that a pulse valve interrupts the flow of a pressurized fluid through a conduit. The pulse valve includes an elongate housing having an inlet configured to couple to the conduit to receive the pressurized fluid, and an outlet configured to couple to one or more tools. In the housing, a valve assembly includes a poppet reciprocating between open and closed positions, and a poppet seat, in which the poppet closes to partially block the flow of pressurized fluid through the valve. A bypass passage is configured to connect with a valve actuation vent port such that when the poppet closes the valve actuation pressure is less than the difference between the pressure up stream of the pulse valve and a pilot within the poppet moves between disparate positions to modify fluid paths within the valve. When the valve is open, a relatively lower pressure is produced by a Venturi effect as the fluid flows through a throat in the poppet seat, to provide a differential pressure used to move the pilot and poppet.

Hydraulic pulses are produced each time that a pulse valve interrupts the flow of a pressurized fluid through a conduit. The pulse valve includes an elongate housing having an inlet configured to couple to the conduit to receive the pressurized fluid, and an outlet configured to couple to one or more tools. In the housing, a valve assembly includes a poppet reciprocating between open and closed positions, and a poppet seat, in which the poppet closes to partially block the flow of pressurized fluid through the valve. A bypass passage is configured to connect with a valve actuation vent port such that when the poppet closes the valve actuation pressure is less than the difference between the pressure up stream of the pulse valve and a pilot within the poppet moves between disparate positions to modify fluid paths within the valve. When the valve is open, a relatively lower pressure is produced by a Venturi effect as the fluid flows through a throat in the poppet seat, to provide a differential pressure used to move the pilot and poppet.

A downhole stroking tool (1) comprising a housing (2), a first chamber (3), a first tool part (4) comprising a pump unit (5) providing pressurized fluid to the chamber, a shaft (6) penetrating the chamber, and a first piston (7) dividing the first chamber into a first chamber section (8, 8a) and a second chamber section (9, 9b). The piston is connected to or forms part of the housing which forms part of a second tool part (10) and is slidable in relation to the shaft so that the housing moves in relation to the shaft, the shaft being stationary in relation to the pump unit during pressurization of the first or the second chamber section, thereby generating a pressure on the piston, wherein the shaft is fixedly connected with the first tool part, and wherein the housing is slidable in relation to the first tool part and overlaps the first tool part.