Patent Application
20220349259
This invention relates to underground operations and equipment for working through stone and stone-like materials, cement, sand and clay. More particularly, the invention relates to a drill assembly adapted for drilling elongate relatively shallow to deep horizontal and vertical holes in underground areas where the underground constituents are hard and difficult to break and structures above ground surface need to remain intact. The invention also extends to a method of using such drill assembly in underground drilling operations and to a method of manufacturing same.
Subterranean land mass does not always comprise soft and easily penetrable soil or materials. Quite often hard rocky areas are encountered which result in breakage of conventional underground drilling equipment. Despite improvements over the years in respect of drill shoes, these improved shoes remain expensive and often incapable of being used in areas where relatively shallow drilling or so-called horizontal directional drilling is required. Such areas include through-passages extending below tar roads, underneath railway and road tunnels, bridges, rivers and through mountains.
Ubiquitous techniques of constructing relatively shallow through-passages, involve utilization of a drill assembly to drill a relatively shallow-to-deep throughbore using a string of drill pipe having a drill bit on a drill shoe attached to a leading end of the drill string. As the drill string is advanced, initially at an oblique angle but later horizontally, into the ground, the drill shoe encounters different rock formations, some of which may be unstable and cause breakage.
The drill string is commonly advanced into the ground by way of compressed air utilizing compressors which further adds to the overall cost of drilling.
Another disadvantage of conventional horizontal directional drilling machine is that it requires use of a reamer after the desired length of throughbore has been obtained while extending, for example, underneath a road. The reamer is detachably mounted to the drill head after initial drilling and pulled back through the throughbore, thus reaming out the throughbore to a larger diameter.
It will be appreciated that the drill assembly of the present invention addresses, at least in part, drawbacks associated with commonly available drilling assemblies and that it is adapted to provide safe passages for utility lines for fibre optic cables, telephone, gas, water, or electricity in areas where conventional drilling assemblies fail, or are too expensive to operate.
It is a further object of the invention to introduce a simplified drill assembly and method of use in a subterranean environment where structures above ground surface need to remain intact.
In broad terms, this invention provides a drill assembly for use in mining or trenchless subterranean boring, the assembly comprising: a drill shoe having spaced apart drill bits disposed on opposing sides and flanks of a body of the drill shoe to facilitate acting as both pilot bore drilling tool and as reaming tool; a drill head demountably mounted to the drill shoe and in communication with directional guidance means remote from the drill shoe and apt to guide movement of the drill head at a slanted angle, vertically and horizontally into the ground; a string of connectable drill rods, having a trailing end and a leading end when connected, and through which a drilling solution can be pumped towards a solution exit provided in the drill shoe; a coupling for linking the leading end to said drill head; and a connector for connecting the trailing end to a D-shackle and swivel of a vehicle, being typically, but not necessarily, a drilling machine.
Moreover, a drill shoe is provided with a shape and configuration designed to act as both pilot bore drilling tool and as reaming tool.
In an embodiment, the drill shoe may comprise a body being symmetrical about a longitudinal axis. The body may comprise an anterior portion in which a recess is defined for releasably locating the drill head and a posterior portion on which multiple bits are releasably affixed or, alternatively, integrally formed with the drill shoe and of uniform construction therewith. The bits may be equidistantly spaced apart. The recess may comprise multiple spaced apart apertures for locating fasteners.
In an embodiment, the posterior portion may be divided into a generally planar front section and a generally planar rear section, which sections join at a central part of the body having the greatest width and depth. Planes of the rear section and front section may form a reflex angle between them of between about 190° and about 230°.
Both the rear and front sections may comprise flanks that each define a chamfered surface slanting away from the respective planes of the rear and front section at an acute angle of between 20° to 80° and which become tapered as they approach respective front and rear ends of the drill shoe.
Multiple apertures may be provided in the rear section for releasably accommodating fasteners for fitting corresponding holes provided in the drill head.
Generally planar lateral sides may be provided for the shoe, which sides are typically disposed directly opposite each other on lateral sides of the longitudinal axis and which extend generally at right angles to the respective generally planar rear and front sections.
Beveled fringes may be provided contiguous with the respective generally planar sides terminating against a flush surface of the anterior portion. The fringes may be slanted away from the generally planar lateral sides.
In an embodiment, the flanks, fringes and sides are all angled away from the central part of the body, which central part has the greatest width and depth, as the flanks, fringes and sides extend towards the respective rear and front ends. Four flanks, four fringes and four sides are provided in an embodiment of the invention.
In an embodiment, the drill head may comprise one or more channels in communication with the drill pipe string and through which a drilling solution can be pumped so as to exit at one or more outlets proximate the recess.
The invention also extends to a method for trenchless subterranean boring and reaming, the method comprising:
The invention further extends to a method of manufacturing a drill shoe, comprising the steps of:
The invention is now described by way of example with reference to the accompanying non-limiting diagrammatic drawings. In the drawings:
In the Figures, reference numeral 10 refers to a drill assembly for trenchless subterranean boring in accordance with the invention.
Similarly, reference numeral 20, as best shown in
As depicted in
Components of the drill assembly 10 include the drill shoe 20 and drill head 50 together with a directional guidance means (although not shown, typically of the joy-stick type) remotely located in relation to the drill shoe and apt to guide movement of the drill head 50 at either a slanted angle, vertically and/or horizontally into the ground. Further components include a string of drill rods or pipes 80, a suitable connector 88 and coupling 86, and a drilling machine 90 with a rotational power D-shackle and swivel 92, as best shown in
The drill head 50 of
As shown in the drawings, the string of drill rods 80 has a trailing end 82 and a leading end 84. The connector 88 ensures operative connection between the trailing end 82 and a power take-off shaft connected to the rotational power D-shackle and swivel 92, while the coupling 86 ensures operative linkage between the leading end 84 to the drill head 50.
The connected pipes 80 are hollow to allow a drilling solution to be pumped therethrough. The pipes 80 are also operatively in fluid communication with the drill head 50.
The unique shape of the drill shoe body 20, as best shown in
Referring to
The drill shoe body 20 also defines a posterior portion 30 on which multiple bits 32, as best shown in
As visible from
Both the rear and front sections 36,34 further define flanks 38.1; 38.2 that slant away from the respective planes of the rear and front section 36,34 at an acute angle of between 20° to 80° and which become tapered as they approach respective front and rear ends of the drill shoe body 20.
Multiple apertures 21 is provided in the rear section 36 for releasably accommodating fasteners such as bolts for fitting corresponding holes 52 provided in the drill head 50.
Still referring to
Two pairs of fringes 42.1;42.2, contiguous with the respective generally planar sides 40.1;40.2, terminate against a flush surface 24 of the anterior portion 22. The fringes 42 are formed to slant away from the generally planar lateral sides 40 in a direction towards the longitudinal axis Y-Y.
As shown in the drawings, two opposing pairs of flanks 38.1; 38.2, two opposing pairs fringes 42.1; 42.2 and two opposing pairs lateral sides 40.1;40.2 are shaped on the body 20. The flanks 38, fringes 42 and sides 40 are all angled away from the central part or broadened waist 36 of the body 20 as they extend towards the respective rear and front ends 44,46, as best shown in
Referring to
In use, the drill assembly 10 as described herein, with its respective components are acquired. Thereafter, by utilisation of suitable bolts extendable through apertures 21 and 52, the drill head 50 is fastened to fit the recess 26 of the drill shoe body 20. The fasteners are preferably suitably torqued with complementary nuts (not shown).
Next, a leading end 84 of a string of drill rods 80, is coupled via a coupling 86 to the drill head 50 at its rear side. Then, a trailing end 82 of the string of drill rods 80 is connected via a connector 88 to a rotational power take-off shaft 92 of the vehicle 90. Actuation of rotation of the power take-off shaft 92 follows, which in turn permits the string of drill rods 80 to rotate with the drill head 50 and drill shoe 20 attached thereto.
Finally, the drill head 50 is guided by way of directional guidance means (not shown), remote from the drill head, to move at a slanted angle, vertically and eventually horizontally into the ground whilst pumping a drilling solution through the shoe 20.
While preferred embodiments of the invention are shown and described, it will be understood that it is not intended to limit the extent of the invention, but rather it is intended to cover all modifications and alternate methods, including: methods, for using the drill assembly 10 falling within the spirit and the scope of the invention.
The applicant believes that the drill assembly 10 of the present invention, at least in part, addresses shortcomings in conventional trenchless drilling units in that it provides a neat, sturdy, functional and cost-effective alternative which has fewer components and are easier to manufacture compared to ubiquitous drilling units and allows for reaming and drilling at the same time.
The invention for which patent protection is sought is defined in the set of claims that follows.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019/06123 | Sep 2019 | ZA | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/058600 | 9/16/2020 | WO |
