A dual-speed and dual-core enhanced drilling equipment which has an outer cylinder, a downhole power device, a large cutting head and a small cutting head. Specifically, the large cutting head has a first centerline, a through hole arranged along the first centerline and a first diameter. The outer cylinder, which is sleeved outside the downhole power device, is connected to the upper drill string with the large cutting head to enable rotation among the large cutting head, downhole power device and upper drill string. The downhole power device has a power generation section capable of generating power, and a rotation output section which connects to, and provides independent power for the small cutting head, so that the small cutting head revolves around the first centerline under the driving of the upper drill string while rotating under the driving of the downhole power device.

A spindle with a mechanism for transferring axial force from an inner drive assembly to an outer drive assembly. The spindle's inner drive shaft is connected to an inner member of a dual-rod pipe by a drive rod having a sliding sleeve. The sleeve is fixed rotationally with the drive shaft, but not axially. When axial force drives the drive rod toward the drive member of the spindle, the sleeve contacts a stop member which is paired to the outer drive assembly. The stop member may be a pair of dowel pins. Axial force is thereby transferred from the inner member to the outer member, allowing such forces to be absorbed by the outer member's larger drive components.

An insert for installation on an inner pipe member of a dual-pipe member assembly. The insert is interposed between an external shoulder formed on the inner pipe member and an internal shoulder formed in an outer pipe member. Shoulder-to-shoulder impacts between pipe members results in wear to the insert, rather than to either pipe member. The insert has the shape of an unclosed loop and is positioned within an endless external groove formed in the inner pipe member.

A pipe assembly used in horizontal directional drilling operations. The pipe assembly has an outer member, an inner member, and first removable collar. The inner member has a polygonal outer profile of uniform shape along its length and is partially contained within the outer member. The first removable collar is supported on the inner member within the outer member and limits relative axial movement of the inner member and the outer member.

The invention relates to a rotary drive arrangement for a drill rod having an outer pipe and an inner rod running at least in sections inside the outer pipe, in particular for double-head and/or overburden drilling, with a first gearbox for driving the inner rod in a rotating manner and a second gearbox for driving the outer pipe in a rotating manner, wherein the first gearbox and the second gearbox are independent of each other. According to the invention provision is made in that the first gearbox and the second gearbox are supported in a common gearbox housing and are surrounded by the same.

A ground drilling device with a drivetrain for rotating a drill string, wherein at least one section of the drivetrain is configured to form a channel between a force transmission element of the drivetrain and the drill string, wherein the channel projects through the force transmission element and the force transmission element may be driven radially in the drivetrain.

Provided is a novel drilling apparatus for drilling into prepared ground surfaces and natural ground conditions. The apparatus includes a mast assembly, a support structure assembly flexibly coupled with the mast assembly, a plurality of drill assemblies affixed to the support structure assembly, and a frame. Also provided is a method of drilling into a ground surface, by providing a drilling apparatus having a mast assembly, a support structure assembly flexibly coupled with the mast assembly, a plurality of drill assemblies affixed to the support structure assembly, and a frame. Each of the drill assemblies include a hollow drill rod with a drill bit at one end, the bit having exterior cutting elements and interior fluid diverters. Pressurized fluid and torque is supplied to the drill rods, and by means of the mast assembly and support structure assembly the drill rods are moved downward so that using the downward and rotational force, and the pressurized fluid, the drill bits drill into the ground surface.

A double-walled drill pipe includes an outer drill pipe, an inner drill pipe and a drill pipe sealing apparatus. The outer drill pipe includes an axial through hole and a wall surface through hole, and the wall surface through hole is disposed in a wall surface of the outer drill pipe to connect the outside of the double-walled drill pipe and the axial through hole. The inner drill pipe is rotatably disposed in the axial through hole, and includes a fluid guiding hole connected to the wall surface through hole. The drill pipe sealing apparatus is disposed between the outer drill pipe and the inner drill pipe. The drill pipe sealing apparatus is axially located between a driving end and a connecting port of the wall surface through hole connected to the axial through hole. A drilling machine including the double-walled drill pipe is also provided.

An insert for installation on an inner pipe member of a dual-pipe member assembly. The insert is interposed between an external shoulder formed on the inner pipe member and an internal shoulder formed in an outer pipe member. Shoulder-to-shoulder impacts between pipe members results in wear to the insert, rather than to either pipe member. The insert has the shape of an unclosed loop and is positioned within an endless external groove formed in the inner pipe member.

A rock drilling arrangement, rock drilling rig and drilling method is provided. The rock drilling arrangement includes a drilling boom, which is mountable to a carrier of the rock drilling rig. The boom is provided with two rock drilling units arranged movably in the longitudinal direction of the boom. Further, the drilling units may be moved independently relative to each other.