Directional multi-blade boring head

A directional multi-blade boring head for a boring machine, the boring machine capable of axially advancing and rotating a drill string about an axis of rotation underground, the drill string ending in the directional multi-blade boring head, said directional multi-blade boring head comprising:

• a body having a central axis of rotation and a planar surface at an oblique angle to the central axis, a plane of symmetry passing through the central axis of rotation and perpendicular to the planar surface;
• a blade assembly mounted to the body at the planar surface and defining a first blade extending at an angle of about 60.degree. from the plane of symmetry on a first side of the plane of symmetry and a second blade extending at an angle of about 60.degree. from the opposite side of the plane of symmetry, said first and second blades each defining deflecting surfaces thereon;
• at least one intermediate blade extending from the blade assembly between the deflecting surfaces;
• the deflecting surfaces of the first and second blades deflecting the boring head as the boring machine advances the drill string without rotation and the directional multi-blade boring head drilling a relative straight borehole as the boring machine advances the drill string with rotation.

A directional multi-blade boring head for a boring machine, the boring machine capable of axially advancing and rotating a drill string about an axis of rotation underground, the drill string end in a directional multi-blade boring head, said directional multi-blade boring head comprising:

• a body having a central axis of rotation and a planar surface at an oblique angle to the central axis, a plane of symmetry passing through the central axis of rotation and perpendicular to the planar surface;
• a blade assembly mounted to the body at the planar surface and defining a first blade extending perpendicular to the plane of symmetry on a first side of the plane of symmetry and a second blade extending perpendicular to the plane of symmetry from the opposite side of the plane of symmetry, said first and second blades each defining deflecting surfaces thereon;
• at least one intermediate blade extending from the blade assembly between the deflecting surfaces and lying parallel to the planar surface;
• the deflecting surfaces of the first and second blades deflecting the boring head as the boring machine advances the drill string without rotation and the directional multi-blade boring head drilling a relatively straight borehole as the boring machine advances the drill string with rotation.

A directional boring head for a boring machine, the boring machine capable of axially advancing and rotating a drill string about an axis of rotation underground, the drill string ending in the directional boring head, said directional boring head comprising:

• a body having a central axis of rotation;
• a deflection structure mounted on the body defining a deflecting surface at an oblique angle to the central axis of rotation of the body;
• at least one roller cone cutter mounted to said body;
• and
• the deflecting surface deflecting the boring head as the boring machine advances the drill string without rotation and the directional boring head drilling a relatively straight borehole as the boring machine advances the drill string with rotation.