Method and apparatus for on-grade boring
First Claim
1. A method for installation of an underground pipe, comprisingboring a pilot hole through the ground at a predetermined grade angle by extending a drill string having a steerable boring bit mounted thereon through the ground;
- upon reaching an end location for the pilot hole, removing the bit from the drill string and attaching an expander having a diameter greater than the pilot hole to the drill string, wherein the expander is backed by an impact device including a striker that delivers repeated impacts to a rearwardly facing surface of the expander, and by a pipe drawn along behind the expander; and
pulling the expander back through the pilot hole at the grade angle while operating the impact device to aid progress of the expander through the ground and pulling the pipe into place behind the expander.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for installation of an underground pipe includes an initial step of boring a pilot hole through the ground at a predetermined grade angle by extending a drill string having a steerable boring bit mounted thereon through the ground. Upon reaching an end location for the pilot hole, the bit is removed from the drill string, and an expander having a diameter greater than the pilot hole is attached to the drill string, which expander is backed by an impact device such as a pneumatic impactor including a striker that delivers repeated impacts to a rearwardly facing surface of the expander, and by a pipe drawn along behind the expander. The expander is pulled back through the pilot hole at the grade angle while the impactor is operated to aid progress of the expander through the ground and pull the pipe into place behind the expander. Typically in this method the replacement pipe is coupled to a rear end of the expander and the boring bit has a sonde housing containing a sonde attached thereto to indicate to an operator the orientation of a steering face on the boring bit.
-
Citations
15 Claims
-
1. A method for installation of an underground pipe, comprising
boring a pilot hole through the ground at a predetermined grade angle by extending a drill string having a steerable boring bit mounted thereon through the ground; -
upon reaching an end location for the pilot hole, removing the bit from the drill string and attaching an expander having a diameter greater than the pilot hole to the drill string, wherein the expander is backed by an impact device including a striker that delivers repeated impacts to a rearwardly facing surface of the expander, and by a pipe drawn along behind the expander; and pulling the expander back through the pilot hole at the grade angle while operating the impact device to aid progress of the expander through the ground and pulling the pipe into place behind the expander. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method for installation of an underground pipe, comprising
boring a pilot hole through the ground at a predetermined grade angle by extending a drill string having a steerable boring bit mounted thereon through the ground; -
upon reaching an end location for the pilot hole, removing the bit from the drill string and attaching a drill head including a cutting reamer having a diameter greater than the pilot hole to the drill string, wherein the cutting reamer is configured to permit steering when rotated over less than 360 degrees and is backed by a pulling device for pulling a pipe along behind an expander, the pulling device including a rotatable connection whereby the cutting reamer can rotate in unison with the drill string without substantial rotation of the pulling device and the pipe; pulling the pipe back through the pilot hole at the grade angle; detecting deviations of the pipe from the grade angle; and steering using the cutting reamer to correct deviations from the grade angle. - View Dependent Claims (11, 12, 13, 14, 15)
-
Specification