GB2426988A

GB2426988A - Tubular drill shoe

Info

Publication number: GB2426988A
Application number: GB0523467A
Authority: GB
Inventors: Geoffrey Kevin Ellison; Francis Alan Hay
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-18
Filing date: 2005-11-18
Publication date: 2006-12-13
Anticipated expiration: 2025-11-18
Also published as: GB0523467D0; GB2426988B

Abstract

A tubular drill shoe 2 for a core tube or drill barrel having said shoe 2 attachable or attached at its normally lower end with said tubular shoe 2 being of circular cross-section and having a normally lower annular end face 3 on which a plurality of cutting teeth 4,5 are located extending downwardly therefrom; ```said annular face 3 having a radial width greater, W1 than the width W2 of each cutting tooth 4,5, wherein some of the teeth, the outer teeth 5, are located closer to the radially outer side of the annular face 3 than other of the teeth, the inner teeth 4, and wherein the inner teeth 4 extend inwardly of the radially inner side of the shoe 2 and the outer teeth 5 extend outwardly of the radially outer side of the end face of the shoe 2. Also disclosed is a core tube or drill barrel for use in core or barrel drilling, or a drill barrel and shoe combination, wherein an internal shoulder or collar or other inwardly extending projection is provided in a lower region of the barrel or at the inner face of the barrel and shoe combination such as to act to retain cut/drilled material within the barrel.

Description

I

A CORE TUBE OR DRILL BARREL AND SHOE

The present invention relates to an improved core tube or drill barrel and shoe therefor for use in core drilling and especially for use in landfill sites.

One form of drilling is known as barrel or core drilling which involves the use of a rotatable hollow steel core tube or drill barrel attached to drilling rods on a drilling machine. At the end of the tube or barrel is a shoe bearing cutting teeth and, which is the attachment that cuts through the material being drilled through. As the barrel is lowered into the ground during drilling, material within the shoe is forced up inside the barrel and this continues until the drill string/rods are raised and the retained material is removed, thereby enabling the empty barrel to be reinserted to enable further drilling.

On known barrel drills there are a number of hardened teeth located on the end cutting face of the shoe. The teeth become worn with use and can be replaced.

The conventional arrangement is to position the teeth on the cutting edge of the shoe so that the teeth are aligned around the end face and each tooth follows the preceding tooth, thereby cutting away a portion of the ground to enable the barrel to enter the void created as it is pushed to the ground.

The resulting void created by the tooth is relatively narrow and creates drag on the rotation of the barrel. This drag has two effects namely:- I) It requires additional energy to rotate the barrel due to frictional losses.

ii) The friction results in erosion of the barrel and shoe. The integrity of the barrel and shoe can be maintained by the addition of metal facing to prolong the life of the barrel and shoe.

The present invention is concerned with modifications to the shoe of the barrel to improve the performance of the barrel drilling technique.

According to a first aspect of the present invention there is provided for a core tube or drill barrel having attachable or attached at its normally lower end, a tubular shoe of circular cross-section having a normally lower annular end face on which a plurality of cutting teeth are located extending downwardly therefrom; said annular face having a radial width greater than the width of each cutting tooth, wherein some of the teeth, the outer teeth, are located closer to the radially outer side of the annular face than other of the teeth, the inner teeth, and wherein, preferably, the inner teeth extend inwardly of the radially inner side and the outer teeth extend outwardly of the radially outer side of the end face of the shoe.

The present invention is also intended to cover a drill barrel and shoe combination in addition to a shoe per Se.

Preferably, the inner and outer teeth are located alternately i.e. such than an outer tooth is followed by an inner tooth which is followed by an outer tooth etc. Preferably the external diameter of the tubular shoe is greater than the external diameter of the barrel to which it is attached such that an extension or outer collar or shoulder is formed by the shoe which thus acts to relieve the pressure on the barrel of the surrounding material being drilled to thus reduce wear of the barrel, and preferably the internal diameter of the shoe is less than that of the barrel such that the radial thickness of the shoe wall is greater than that of the barrel such that an inner collar or shoulder is formed by the shoe which shoulder acts to retain cut material within the barrel. (

Preferably a portion of the inner and outer teeth overlap the circular centre line of the tooth carrying, annular lower end face of the barrel auger of the shoe. Preferably, as mentioned, also a portion of each inner tooth will extend inwardly over the edge of the barrel or shoe and a portion of each outer tooth will extend over the outer edge of the barrel or shoe when provided.

Preferably the barrel and/or shoe will have a metal facing to prolong the life of the component.

According to a second aspect of the invention there is provided a core tube or drill barrel for use in the drilling technique of core or barrel drilling, or a drill barrel and shoe combination, wherein an internal shoulder or collar or other inwardly extending projection is provided in a lower region of the barrel or at the outer face of the barrel and shoe combination such as to act to retain cut/drilled material within the barrel. Preferably the shoulder is provided by having the tubular shoe of a smaller inner diameter than that of the barrel such that the shoe forms a inner inwardly extending shoulder adjacent the barrel end. Alternatively, a tubular insert of lesser inner diameter that that of the barrel may be provided between the barrel or shoe or at the end of the barrel.

According to a third aspect of the invention there is provided a barrel and shoe combination for use in the drilling technique of core or barrel drilling, wherein the outer diameter of the shoe is greater than the outer diameter of the barrel so as to provide an external shoulder or collar or other outward projection at the lower end of the barrel such as, in use, to act to reduce the pressure on the barrel of surrounding material being drilled.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a perspective view from below of a cylindrical barrel drill with shoe secured to the lower end and the cutting teeth located around the annular end face of the shoe; Fig. 2 is an inverted plan of the barrel and shoe of Fig. 1 looking upwards; and Fig. 3 is a side elevation of the barrel and shoe of Figs. 1 and 2.

In Figs 1 to 3 a tubular barrel 1 of circular cross-section and smooth outer surface is illustrated having a shoe 2 detachably secured to the lower end of the barrel 1 by means of screw threads (not shown) in known manner.

The shoe 2 has a cylindrical/tubular wall of thickness Ti and a lower annular end face 3 of radial width Wi.

A plurality of identically shaped teeth 4, 5 are located circumferentialty spaced apart on the annular end face 3. In the embodiment illustrated there are five inner teeth 4 and five outer teeth 5 alternately arranged although up to eight inner teeth and eight outer teeth are preferably envisaged.

The inner and outer cutting teeth 4, 5 all face generally in the same circumferential direction in that their cutting leading edges are on the upstream side with respect to the normal direction of cutting rotary movement.

In Fig. 2, the drilling direction is anti-clockwise with the wider end of the teeth being the cutting edges.

Each tooth 4, 5 has maximum radial width W2 which is less than the radial width Wi of the annular end face 3 of the shoe 2.

The annular end face 3 has an imaginary circular center line (not shown) and the inner teeth 4 and arranged offset with respect to the outer teeth 5 and either side of the centre-line and partly overlapping such. It will be seen the trading or rear ends of the inner teeth 4 each extends slightly inwardly of the inner edge of the end face 3 whilst the trailing or rear ends of the outer teeth 5 each extends slightly outwardly of the end face 3 The teeth 4 will be attached to the barrel in known manner by using the conventional method of tooth holders enabling the teeth to be replaced when worn. The teeth will preferably be standard, pre-existing teeth as are readily available on the market and generally comprise a base welded to the shoe and four quadrilateral walls - two opposite side walls being parallel and of the same dimensions and two parallel end wall with one end wall being bigger than the opposite one and an inclined bottom surface or tip being somewhat in the manner of an inverted inclined "pitched roof".

It will be seen that according to the second aspect of the invention, the radial thickness Ti of the outer wall of the shoe 2 is greater than to radial thickness T2 of the wall of the barrel with both components having the same outer diameter such that when connected together, the outer surface of the shoe 2 extending outwardly of the outer surface of the barrel 1 to form a shoulder 2A and the shoe 2 forms an inner collar or shoulder 6 extending such as to act to retain cut/drilled material such as soil or clay or preferably drilled landfill material.

Thus the teeth 4, 5 are arranged on the inner and outer edges 3A, 3B of the shoe 2. Each tooth 4, 5 will cut through new material as well as following part of the area previously cut through by the preceding tooth. The void created is consequently wider than the conventional arrangement and the shoe 2 and the shoe 2 and barrel 1 are subjected to reduced friction.

Although tooth wear may be higher due to each tooth cutting through more material on each rotation, this is more than offset by the reduced energy consumption due to frictional reductions on the barrel and barrel and shoe wear. /

It has been unexpectedly found that because the teeth cut outwardly of the outer cylindrical surface of the shoe and/or because the shoe extends beyond the outer surface of the barrel, the barrel is subject to less wear and the drilling energy requirements are reduced and the drilling depths achieved are increased.

The barrel and shoe will preferably have metal facing to prolong the life of the components as in the conventional shoe.

In order for the barrel drilling system to operate effectively it is necessary to retain the core of the material that has been drilled through, within the barrel, to enable it to be removed. Removal of the core of material that has been drilled through is called recovery".

If the barrel is being used in dry material then the retention of material is easily achieved. However, if the material being drilled through is damp or wet then the core of material for recovery can be lost through the open end of the drilling shoe. This is particularly common when using a barrel auger to drill through waste on landfill sites, at depth, when leachate is encountered. It is a frequent occurrence that deep boreholes on landfill sites cannot be installed to the required depth due to poor recovery.

It can be seen from the drawing that the width of the shoe or the thickness Ti of the wall thereof forms a inner collar or shoulder at the attachment point with the barrel 1. The increased width created by the offset teeth 4, 5 on the shoe 2 enables the collar 9 to penetrate the ground easily.

When material has passed through the collar 9 it expands and is retained within the barrel. During recovery, the protruding collar 6 offers support to the material within the barrel and retention rates of material are increased. f

Claims

1. A tubular drill shoe for a core tube or drill barrel having said shoe attachable or attached at its normally lower end, with said tubular shoe being of circular cross-section and having a normally lower annular end face on which a plurality of cutting teeth are located extending downwardly therefrom; said annular face having a radial width greater than the width of each cutting tooth, wherein some of the teeth, the outer teeth, are located closer to the radially outer side of the annular face than other of the teeth, the inner teeth, and wherein the inner teeth extend inwardly of the radially inner side of the shoe and the outer teeth extend outwardly of the radially outer side of the end face of the shoe.

2. A drill shoe as claimed in claim 1, in which the inner and outer teeth are located alternately i.e. such than an outer tooth is followed by an inner tooth which is followed by an outer tooth etc.

3. A drill shoe as claimed in claim 1 or 2, in which a portion of the inner and outer teeth overlap the circular centre line of the tooth- carrying, annular lower end face of the barrel auger of the shoe.

4. A drill shoe as claimed in any of claims 1 to 3, in which a portion of each inner tooth extends inwardly over the edge of the barrel or shoe and/or a portion of each outer tooth extends over the outer edge of the barrel or shoe when provided.

5. A drill shoe as claimed in any of claims I to 4, in combination ith a drill barrel, in which the external diameter of the tubular shoe is greater than the external diameter of the barrel to which it is attached such that an extension or outer collar or shoulder is formed by the shoe which thus acts to relieve the pressure on the barrel of the surrounding material being drilled to thus reduce wear of the barrel.

6. A drill shoe as claimed in any of claims 1 to 4, in combination with a drill barrel or a combination as claimed in claim 5 in which the internal diameter of the shoe is less than that of the barrel such that the radial thickness of the shoe wall is greater than that of the barrel such that an inner collar or shoulder is formed by the shoe which shoulder acts to retain cut material within the barrel.

7. A drill shoe or drill shoe and barrel combination as claimed in any of claims 1 to 6, in which the barrel and/or shoe have a metal facing to prolong the life of the component.

8. A core tube or drill barrel for use in core or barrel drilling, or a drill barrel and shoe combination, wherein an internal shoulder or collar or other inwardly extending projection is provided in a lower region of the barrel or at the inner face of the barrel and shoe combination such as to act to retain cut/drilled material within the barrel.

9. A core tube or drill barrel or a drill barrel arid shoe combination as claimed in claim 8, in which the shoulder is provided by having the tubular shoe of a smaller inner diameter than that of the barrel such that the shoe forms a inner inwardly extending shoulder adjacent the barrel end.

10. A drill barrel or combination as claimed in claim 8, in which a tubular insert of lesser inner diameter that that of the barrel is provided between the barrel or shoe or at the end of the barrel.

11. A barrel and shoe combination for use in the drilling technique of core or barrel drilling, wherein the outer diameter of the shoe is greater than the outer diameter of the barrel so as to provide an external shoulder or collar or ( other outward projection at the lower end of the barrel such as, in use, to act to reduce the pressure on the barrel of surrounding material being drilled.

12. A drill shoe and drill barrel combination substantially as herein described with reference to the accompanying drawings.

12. A drill shoe or drill shoe and barrel combination or drill barrel substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows I0 CLAiMS 1. A tubular drill shoe in combination with a core tube or drill barrel having said shoe attachable or attached at its normally lower end, with said tubular shoe being of circular cross-section and having a normally lower annular end face on which a plurality of cutting teeth are located extending downwardly therefrom; said annular face having a radial width greater than the width of each cutting tooth, wherein some of the teeth, the outer teeth, are located closer to the radially outer side of the annular face than other of the teeth, the inner teeth, and wherein the inner teeth extend inwardly of the radially inner side of the shoe and the outer teeth extend outwardly of the radially outer side of the end face of the shoe, characterised in that the external diameter of the tubular shoe is greater than the external diameter of the barrel to which it is attached such that an extension or outer collar or shoulder is formed by the shoe such as to act to relieve the pressure on the barrel of the surrounding material being drilled to thus reduce wear of the barrel.

2. A drill shoe and drill barrel combination as claimed in claim 1, in which the inner and outer teeth are located alternately i.e. such than an outer tooth is followed by an inner tooth which is followed by an outer tooth etc. 3. A drill shoe and drill barrel combination as claimed in claim 1 or 2, in which a portion of the inner and outer teeth overlap the circular centre line of the tooth-carrying, annular lower end face of the barrel auger of the shoe.

4. A drill shoe and drill barrel combination as claimed in any of claims 1 to 3, in which a portion of each inner tooth extends inwardly over the edge of the barrel or shoe and/or a portion of each outer tooth extends over the outer edge of the barrel or shoe when provided. Ii

5. A drill shoe and drill barrel combination as claimed in any of claims 1 to 4, in which the internal diameter of the shoe is less than that of the barrel such that the radial thickness of the shoe wall is greater than that of the barrel such that an inner collar or shoulder is formed by the shoe which shoulder acts to retain cut material within the barrel.

6. A drill shoe and drill barrel combination as claimed in any of claims 1 to 5, in which the barrel and/or shoe has a metal facing to prolong the life of the component.

7. A drill shoe and drill barrel combination as claimed in any of claims 1 to 6, wherein an internal shoulder or collar or other inwardly extending projection is provided in a lower region of the barrel or at the inner face of the barrel and shoe combination such as to act to retain cut/drilled material within the barrel.

8. A combination as claimed in claim 7, in which the shoulder is provided by having the tubular shoe of a smaller inner diameter than that of the barrel such that the shoe forms a inner inwardly extending shoulder adjacent the barrel end.

9. A combination as claimed in claim 7, in which a tubular insert of lesser inner diameter that that of the barrel is provided between the barrel or shoe or at the end of the barrel.

10. A barrel and shoe combination for use in the drilling technique of core or barrel drilling, wherein the outer diameter of the shoe is greater than the outer diameter of the barrel so as to provide an external shoulder or collar or other outward projection at the lower end of the barrel such as, in use, to act to reduce the pressure on the barrel of surrounding material being drilled.

11. A combination as claimed in claim 10, in which at east the outer surface of the shoe has a metal facing to prolong the life of the shoe.