US3407888A - Device and method for the rapid execution of boreholes in all types of ground - Google Patents

Description

3,407,888 DEVICE AND METHOD FOR THE RAPID EXECUTION OF BORE-HOLES R. GRAIPIN IN ALL TYPES OF GROUND Filed April 4, 1966 Oct. 29, 1968 Fig.3

Im/en {or Karyn/mo Gra/p/n MMMEM Hi15am 2 ys 3,407,888 Patented Oct. 29, 196 8 States Patent Oflice ABSTRACT on THE DISCLOSURE 'A drilling apparatus including a drill stem disposed in an auger, and drive means for driving the drill stem and auger at different speeds. A working tool is operatively connected to the drill stem, and cam means are provided on the auger and the working tool and are adapted to impart a reciprocal movement to the tool upon a relative rotation between the drill stern and auger.

There exist numerous methods of boring adapted to the nature of the ground through which it is desired to pass.

In rocky ground, drilling is carried out either by percussionwith the aid of driving equipment, used dry or with water, of mining drills with air or water; or by rotation, making use of the rotary system using clear water or sludge, with boring machines having tools using shot, tungsten carbide or diamonds for example.

In soft ground, the most generally employed method is driving by means of a boring-bit, either dry or with injection of water, which eliminates the necessity of assembling and dismantling of the drilling gear for the use of the drag for cleaning the borehole.

When the land has little cohesion, it is coffered internally by means of tubes which are driven in by percussion, simultaneously or not with the drilling operation. Another method which is less frequently employed is the use of continuous augers based on the principle of the Archimedean screw. These augers work without water supply and give very good results from the point of view of drilling progress in land whether coherent or not, on condition that it is not desired to find the exact location in depth of the sample of ground brought to the surface. a In the case where the ground has friable layers from top to bottom, with or without cohesion, alternating with rocky layers, and where it is not desired for various reasons (too great losses, blocking-up of the water intakes, difiiculties of installation of the equipment, etc.) to utilize sludge, a first solution in the case of the percussion, rotary, rotating boring machine equipment, consists in driving a tube at the same time as the boring tool, through formations of different consistencies. For this purpose, it is appropriate to provide at the foot of the column of tubing a toothed shoe projecting with respect to the outer diameter of the tubing. This shoe has the function of an annular cutter and should play the same part as mine-boring cutters actuated by compressed air.

This solution has the following disadvantages:

(1) It is difficult, in certain ground formations to impart to the tube a circular motion for the purpose of facilitating the uniform attack of the shoe in the ground;

(2) The shock transmitted to the shoe by the weight striking on the head of the tubing column is deadened and all the more so as the column increases in length, with the result that the drilling efficiency becomes increasingly low;

. (3) In the case of ground having a considerable gripping force on the tubes, it becomes impossible to push the latter sufliciently deep, which makes it necessary to employ telescopic tubing;

(4) Even in the case of ground which does not have a large gripping force on the tubes, when once the drilling is finished there is always a certain difiiculty in extracting the tubes, which results in considerable loss of time;

(5) It should be observed that the use of any one of these equipments with injection of Water under pressure in order to force upwards the drilling debris, results in the moisture conditions of the ground being considerably modified. If it is desired to measure in situ the resistivity of the ground in depth, the results obtained are absolutely inaccurate.

A second solution consists of the use of continuous helicoidal augers equipped at their base with a boring-bit with blades which cut the bottom of the hole before the material separated from the ground is engaged by the sloping blade of the auger.

This solution has a number of drawbacks:

(1) In heterogenous ground such as alluvials composed of elements of very varied sizes, the tool tears out the elements instead of cutting them, which results in the necessity of having an auger with a large pitch and a substantial width of blade of the helix, for the purpose of forcing upwards the large elements, which involves a non-useful increase in the driving power;

(2) The speed of rotation of the helicoidal auger is slow, so as to make it possible to obtain a high torque with a driving motor having a reasonable output. This speed of rotation is incompatible with the high speed required by the boring-bit with blades, in order to obtain a high drilling elficiency;

(3) For the purpose of obtaining rapid progress of drilling in certain formations of hard rock, there is an advantage in making use of their fragility and therefore employing percussion methods. Unfortunately, the conventional helicoidal auger does not permit of the use of this method.

Briefly summarized, the drilling apparatus of the present invention comprises a first and second drive means adapted to rotate at different speeds; a hollow rotating extraction cutting auger operatively connected to said first drive means; a drill stem disposed in said auger and operatively connected to said second drive means; a working tool; connecting means operatively connecting said tool to said drill stem to permit relative axial movement therebetween; first and second cam means fixed to said auger and to said tool, respectively, said first and second cam means being disposed in a facing relationship; and means to control the relative axial position of said auger and said drill stem to move said cam means to and from a reciprocal contact position in which a corresponding reciprocal movement is imparted to said tool.

To this end, the auger, divided-up into elements of variable lengths compatible with its use, assembled together by screwing, keying or by any other known method of assembly, comprises a hollow core on which is wound one or more turns projecting slightly with respect to the outer diameter of the hollow core.

The lower extremity of the core of the auger is provided with an annular piece having on its lower face teeth forming the first cam means, said face teeth having inclined or rounded faces, that is to say alternations of hollows and bosses so as to form for example, the profile which is obtained with balls of steel or any other material mounted in the ring at regular or irregular intervals.

The upper extremity of the core is provided with a driving head adapted for rigid fixing in rotation to a mechanism rotating at low speed.

The drilling tool comprises blades capable of working 0 equally well by simple rotation or by rotation-percussion.

This tool is made-up of two parts: a central portion which drills in the first place a centering pilot-hole in the ground; and an annular portion boring the drilling hole to a diameter slightly greater than the outer diameter of the helicoidal auger. This part of the working tool comprises an annular internal part which is the replica of that.fixed under the hollow core of the helicoidal auger, but in which the profile with teeth having inclined or rounded faces is turned upwards to form the second ,cam,means.

vpie e can .be inserted between the central portion of the tool and the hollow shaft. This has the purpose of permitting the tool to oscillate u and down with a small 13 is lower than the base of theblades 14 of the annular amplitude, without this oscillation ,being transferred .to v the driving .shaft. This intermediate part may be, by way of example, similar to. the sliding coupling of a splined shaft and hub.

. The driving. shaft is divided into elements of lengths correspondingto those of the elements of the auger. In the drilling tool are formed passage holes communicating with the central conduit of the driving shaft or of the intermediate piece. The upper extremity of the driving shaft is provided with a coupling member capable of being fixed to a driving mechanism rotating at high speed. This member is provided at its upper portion with a rotating injection head which communicates through a flexible pipe with an injection pump.

The above-mentioned means to control the relative axial position of the auger and the drill stem is located at the head of the assembly.

The invention is also applicable to methods of utilization ofthe device and to details of construction which are brought out in the description which follows below of one form of construction illustrated 'by way of example by the accompanying drawings, in which:

FIGURE 1 shows a partial cross-sectional view of the upper element of an auger intended for mounting on a driving device;

FIGURE 2 is also a partial section showing the lower extremity element of the auger, equipped with its cutting tools;

FIGURE 3 shows a driving device, the motor of which has not been shown.

As can be seen from FIGURES l and 2, afiat steel strip 1 is wound in a spiral of short pitch on thehollow core 2 of the auger. The steel strip is fixed to the core by Welding or by any other known process. For the easy use of this auger, the latter is divided into elements of more or less great length. These are assembled to each other by a coupling withclaws 3 andslots 4 which correspond, completed by ascrew 5 passing through two elements at the level of their engagement. It will be understood that use can be made of any other known system of assembly.

The base of thehollow core 2 of the last element (FIG- URE 2) terminates at its lower portion in anannular member 6 of treated steel of high strength, provided on its lower face withteeth 7, the profile of which is similar to the teeth of a ratchet wheel. The upper portion of the hollow core is provided with a drivinghead 8 which, in the case of the leading auger element, is fixed by means of asleeve 9 with bolted bushes to theshaft 10 of a driving device such as that shown in FIGURE 3, rotating at low speed.

The drilling tool comprises acentral portion 11 and anannular portion 12. These two portions 'both carry at their lower parts theblades 13 and 14 and are assembled 'by a threaded portion 15 or any other known system. For the lubrication of their blades, they are provided with holes orpassages 16 communicating with anaxial conduit 17 in thecentral portion 11.

Thecentral portion 11, in which the ba e of he bladesportion 12, is intended to cut a centering pilot-hole in the ground. Thecentral portion 11 of the tool has an internal annular ring ofteeth 18 of treated steel of high strength, which is similar to the teeth-7 terminating the base of the hollow core .of the auger but is .distinguishedfrom; the latter by the fact that' it is turned and faces upwards.

The central portion of the tool is rigidly fixed by means of threading or by any other known system of assembly to asleeve 19 capable of slidingin the hollow 'core- 2. This sleeve is mounted with 'sliding'splines 20 on a hollowsplined shaft 21. In 'order to prevent thesleeve 19 from leaving thehollow shaft 21 arstop-member 22 fixed rigidly to thesplined sleeve 19 by threading or by any other known system, is capableof moving vertically between twostops 23 and 24 provided on the hollow' shaft; 21, while leaving the sleeve a certain freedom of vertical movement. The splinedhollow shaft 21 is rigidly fixed at itsupper portion 25 by threading or by any other known system with a drilling-gear. This drilling gear, which can rotate in the axis ofthe augers, is constituted byhollow rods 26 assembledtoeach other by sleeves with the aid of a coupling device constituted bylugs 27 engaged in the corresponding slots 28'and by screws or studs (not shown) engaged: inholes 29 and 30 passing through the male and female sleeve portions, it being possible to replace this arrangement by 7 any other known system (FIGURE l).-

The upper portion of the hollow drilling gear (FIG- URE 1) is rigidly fixed by means of the above coupling device with anothershaft 31 rotating at high speed inside thefirst shaft 10 of the driving device shown in FIGURE 3. To this end, thissecond shaft 31 is provided at its extremity with a socket pierced withholes 30 and is terminated bylugs 27 corresponding to theslots 28 of the upper portion of the elements of the drilling gear. I

One of the two drivingshafts 10 and 31 is adjustably mounted in height with respect to the other, the adjustment being effected-for example by means of a system of ascrew 36 andnut 37 actuated by a hand-wheel 35.

The central conduit is the drilling gear communicates by an axial conduit formed in the second shaft and through the intermediary of a rotary joint .(not shown) with-a water-injection head 32. By this'means, the. rotating drilling gear does not cause any movement. of rotation of theinjection head 32 and the height-regulatingdevice 35, 36 and 37. l r

The driving device shown in FIGURE 3 is itselfactuated by a motor (not shown) the shaft of which is coupled directly or throughthe intermediary of a conventional transmission to theinput shaft end 33 of the device. This latter is effected in the form of a double change or a double speed-varying gear which enables the speeds of the hollow'concentric output shafts -10 and31 to be regulated independently of each other. This device is even provided in such manner that it enables the direction of rotation of the drilling gear to be reversed. Alever 34 mounted on the device itself permits the control of the speeds and the reversal of the direction of rotation.

An appropriate frame supports the driving device and the auger.

The whole of this drilling equipment according to the invention can be put into operation following two'methods to which the invention is also applicable. In one, the boring tool works solely in rotation and in the other it works by rotation-percussion. Y

In the first method, the height of the drivingshaft 31 of the drilling gear is adjusted with respect to that of the auger in such manner that theinternal toothed ring 18 of the tool does not come into contact with thetoothed ring 7 located under the hollow core of the auger. p I

By causing the tool and theauger to rotate at their respective speeds, the tool lubricated by injection water passing out through thepassages 16 first attacks the ground by wear and reduces it to fine elements. These are then engaged by the auger which raises these elements to the surface of the ground.

If it is desired to take samples intact, thecentral portion 11 of the tool is freed from itsannular portion 12. The assembly comprising theinternal shaft 21 and thecentral tool 11 is removed and is replaced by a core-sample tool which takes the place of the central tool.

In the second method, the vertical position of the driving shaft of the driven gear is regulated with respect to that of the auger, this time in such manner that theinternal toothed ring 18 of the tool comes into contact with thetoothed ring 7 located under the hollow core of the auger. By causing the tool and the auger to rotate at their respective speeds, the teeth or projections of thering 18 fixed to the tool slide over those of thering 7 fixed to the hollow core of the auger, and the tool is then given small vertical alternating movements which produce successive shocks of the tool on the ground. The frequency of the shocks can be increased if the tool and the auger are rotated in opposite directions. These opposite movements furthermore facilitate the handling of the ground crushed by theblade 1 of the auger.

The device according to the invention and the methods for its application which make it possible to drill in all types of ground, ofier the following particular advantages:

(1) At equal depths with respect to conventional augers, this improved auger does not necessitate large driving power. In fact, by virtue of the different speeds of the tool and the auger, the tool can be rotated at high speed while the auger rotates at a low speed, this auger absorbing an average power with a high torque. As the tool reduces the materials to fine elements, it is no longer necessary to have an auger comprising a large pitch and a considerable width of helix in order to bring up the materials. This results in a reduction of the power required.

(2) It is possible to make use of percussion for passing through certain types of ground.

(3) The hollow core of the auger which serves as a tubing moves readily in ground which has a large gripping force by virtue of itshelix 1 which plays the part of a stirrer-mixer. The drilling can be carried out deeply and the removal of the whole gear is easy.

(4) In the case of use of percussion, the successive shocks have their origin above the tool and are transmitted directly to the ground without being deadened.

'This method makes it possible to obtain a shock frequency which is particularly high when the tool and the auger are rotating in opposite directions. The association of these two effects makes it possible to obtain a high efficiency.

(5) Water is employed solely as a simple lubricant and does not serve in any manner to bring up the drilling debris; it is therefore retained in a very restricted volume of ground and for this reason practically does not modify the resistivity of the ground in depth.

(6) It is possible with a simple'adjustment and without the necessity of dismantling and reassembling the gear, to change-over, according to the ground to be bored, from drilling by rotation to drilling by rotationpercussion. This results in a very great flexibility of operation.

(7) The device can work in all positions.

What I claim is:

1. A drilling apparatus comprising first and second drive means adapted to rotate at dilferent speeds; a hollow rotatable extraction cutting auger operatively connected to said first drive means; a rotatable drill stem disposed in said auger and operatively connected to said second drive means; a working tool; connecting means operatively connecting said tool to said drill stem to permit relative axial movement therebetween; first and second cam means fixed to said auger and to said tool, respectively, and disposed in a facing relationship; and means to control the relative axial position of said auger and said drill stem to move said cam means to and from a reciprocal contact position in which a corresponding reciprocal movement is imparted to said tool upon rotation of said auger and said drill stem.

2. The apparatus ofclaim 1, wherein said drill stem comprises an axial water injection conduit opening to the exterior by at least one passage formed in said tool.

3. The apparatus ofclaim 1, wherein said first and second cam means are each constituted by a ring provided on one of its faces with projecting portions with inclined surfaces and arranged in such a manner that when the rings are in contact, the inclined surfaces of one ring slide over those of the other, thus imparting said reciprocal movement to said tool.

4. The apparatus ofclaim 1, wherein said drive means comprises an input shaft, two hollow and concentric output shafts adapted to be coupled, one to the auger and the other to the drill stem, and a speed varying box and gear system permitting a reversal of direction of rotation of said output shafts.

5. The apparatus ofclaim 1, wherein the drill stem and the auger are each composed of assembled sections.

6. The apparatus ofclaim 1, wherein said tool is composed of a centering boring bit around which are disposed the blades of an annular boring bit.

7. The apparatus ofclaim 1, wherein said tool is composed of an annular boring bit equipped with a central core sample tool.

8. The apparatus ofclaim 1, wherein said connecting means is in the form of a supporting rod fixed to said tool and coupled to the extremity of said drill stem by a sliding coupling with splines, said axial movement being limited by means of a stop member fixed to said rod and engaged between two end-of-travel abutments provided in said drill stem.

9. The apparatus ofclaim 1, wherein said connecting means is in the form of a supporting rod fixed to said tool and coupled to the extremity of said drill stem by a sliding coupling with splines, said axial movement being limited by means of a stop member fixed to said drill stem and engaged between two end-of-travel abutments provided in said rod.

References Cited UNITED STATES PATENTS 701,547 6/1902 Davis 175l7l 2,701,124 2/1955 Pronio 175- 2,764,387 9/1956 Dionisotti -173 X 2,950,087 8/1960 Gregory 175-171 X NILE C. BYERS, 111., Primary Examiner.

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