US3467210A - Boring holes in rock - Google Patents

Description

Sept. 16, 1969 H, LAUTSCH ET AL BORING HOLES IN ROCK 8 Sheets-Sheet 1 Filed July 14, 1967 3 I; I l i I l I I I l I I l I I. I m9 m9 8? g H m9 N LII lvl 87 5 H 9 N 6E IN VENI'ORS Hans-Z u div/9 .14 (02%? Herman/7 LAUTSCl-l Pele/- HERMA NNS Klaus HRMANN$ Sept. 16, 1969 H, L u'rscH ETAL BORING HOLES IN ROCK 8 Sheets-Sheet 2 Filed July 14, 1967 NQE INVENTO Sept. 16, 1969 Filed July 14, 1967 BORING HOLES IN ROCK H. LAUTSCH ETAL 8 Sheets-Sheet 3 Sept. 16, 1969 LAUTSCH ETAL BORING HOLES IN ROCK 8 Sheets-Sheet 4 Filed July 14, 1967 //V VZNTORS Hans iuo'w/g 1A 608 Hermann A (/78 CH Pefer l/'RMA NNS K lavas HHPMAA/NS v GI Sept. 16, 1969 u'rsc ET AL BORING HOLES IN ROCK 8 Sheets-Sheet 5 Filed July 14, 1967 INVENTORS fiansi udlwjg 1A [08 Hermann LAl/TSCH Pefer HERMAN/V5 Klaus HERMAN/v5 Sept. 16, 1969 u'rscH ET AL 3,467,210 BORING HOLES in ROCK Filed July 14, 1967 8 Sheets-Sheet 6 507 T 507 505 w5o 5 572 INVENTORS:

Hans-ladm'g M605 Hermann LAUTSCH Pe/er HERMANNS Klaus HERMAN/Vs Sept. 16, 1969 u sc ET AL 3,467,210

BORING HOLES IN ROCK Filed July 14, 1967 8 Sheets-Sheet 7 //V WEN/0R5 Hans-Ludwig ./A (03 filer/77mm LAUTSC/y Peter I/ERMA/VNS Klaus I-IERMANNS Sept. 16, 1969 u1's ETAL BORING HOLES IN ROCK 8 Sheets-Sheet 8 Filed July 14, 1967 INVENTORS United States Patent Int. Cl. E211) 9/22; lZZlc 23/00, 13/04 US. Cl. 175386 Claims ABSTRACT OF THE DISCLOSURE The specification describes various forms of boring heads having cutting tools arranged to cut along a helical or helical-spiral path and thus produce a forward thrust. When such tools are placed on the periphery of the head they produce a correcting thrust when the head strays from a softer stratum into a harder one.

The present invention relates to boring apparatus for producing circular holes in rock and more particularly but not exclusively to such boring apparatus in which a rotation of tools on the apparatus produces a thrust tending to force the apparatus forward along the direction of the hole being bored.

Generally the invention is intended to be applicable to apparatus for boring holes in rock of many different sizes extending from holes of the order of one foot the diameter to those of the largest size used in coal mining practice.

An object intended to be obtained with certain forms of the invention is to place the tools at the periphery of the boring apparatus in such a manner that they produce a forward thrust along the axis of the hole owing to their engagement with the adjacent rock. An advantage of such a measure is that if the boring apparatus is used in a stratum which is softer than the underlying and overlying stratum as is commonly the case with coal, and if the boring apparatus runs against one of the harder strata, the tool at the periphery of the apparatus will, owing to the greater hardness, produce a relatively greater thrust and thus tend to turn the apparatus so that it runs back into the softer strata in which it is intended to operate. This is an advantage over constructions in which a. heavy axial feed pressure is required since if such devices engage a harder stratum below or above the stratum in which they are intended to be working they tend to be tilted by a harder stratum towards it.

The present invention consists in a boring apparatus for producing circular holes in rock comprising a frame adapted to be turned about an axis coinciding with the axis of the hole to be produced and to be fed along the axis of the hole, rock cutting means arranged on the frame and to rotate with the frame about the axis of the hole so that any given point on the cutting means follows a helical path corresponding with the rotation of the frame and its feed along the axis, the principal cutting action of the cutting means corresponding to a torque about the frame axis, the cutting means having the further feature that it extends along at least one line which when projected radially on to an imaginary cylinder around the frame axis it produces a helix.

Preferably the apparatus is so designed that when used in the stratum for which it is intended, for instance coal, only torque is required to drive it and the axial thrust is produced by the action of the cutting tools.

In accordance with a preferred feature of the inven- 3,467,210 Patented Sept. 16, 1969 tion the cutting means are arranged on at least two such lines.

Preferably each line along which the cutting means extends is itself a helix.

The frame can have a substantially cylindrical surface, coaxial with the frame axis, on which the cutting means is mounted, this cutting means being arranged to cut the hole to its final dimension. The cutting means can comprise separate cutting tools of which the most forward is arranged to cut a helical groove which is progressively widened in a rearward direction by the following cutting tools of the cutting means.

The projection of the line on which the cutting means is arranged on to a radial plane can be a spiral.

The frame can comprise two sections arranged to rotate in opposite directions about the hole axis, and two such cutting means, one cutting means being arranged on each such frame section. The outer-most of the two frame sections can be arranged to rotate at a slower speed than the inner one so that the net torque exerted on the frame is zero.

The angle of the helix of the line on which the cutting tools are arranged can have such a large value that cutting tools in the form of cutting rollers can be used.

Some embodiments of the invention are now described with reference to the attached drawings.

FIG. 1 is a diagram of a conventional boring apparatus.

FIG. 2 is a developed view of a boring apparatus in accordance with the invention with boring tools arranged to engage a coal seam in a substantially radial-tangential direction.

FIG. 3 is a diagram of an embodiment to the invention in a position corresponding to that of FIG. 1.

FIG. 4 is a diagram showing the action of tools of the boring apparatus shown in FIG. 2.

FIG. 5 shows, diagrammatically, a further embodiment to the invention in perspective view from the front.

FIG. 6 is a perspective view of a further embodiment Of the invention.

FIG. 7 is a view corresponding to FIG. 6 showing a modified embodiment to the invention.

FIG. 8 is a side view of the cutting tools of the boring apparatus in accordance with FIG. 7.

FIG. 9 is a diagram showing a helicoidal surface.

FIGS. 10 and 11 show a further embodiment of the invention in which the frame is generally wheel-shaped.

The boring apparatus of conventional construction shown in FIG. 1 is provided with axially acting cutting tools, that is to say tools which principally require an axial thrust, rather than a torque tending to rotate them about the axis of the hole, on its front face 100. The boring apparatus is shown in a coal seam 101 softer than the strata above and below it. The boring apparatus 102 is attached to the end of a driving rod 103 which is driven in a conventional manner by a boring or drilling machine. Reference numerals 104 and 105 denote the boundaries of the overlying and underlying strata respectively.

If the feed or thrust force 109 acting on the boring apparatus is equally distributed by the front face of the apparatus on to the coal there will be no tilting movement acting on the apparatus and it will remain in a central position.

If however the boring apparatus for some reason or other follows the path 106 shown in broken lines and runs into the boundary 105 of the lower harder stratum there will be more resistance to the bottom of the front face of the boring machine than to the rest of it as indicated by arrow 107. In consequence the counter pressure on the front face will tend to act along the arrow 108 displaced from line 109 and the boring apparatus will tend to increase its angle of dip in a saggital plane and leave the softer coal seam.

In accordance with one form of our invention we therefore provide on the front of a boring apparatus 102a picks or similar working tools arranged on the front of the cylindrical outer face of the apparatus which is arranged to rotate. These picks out the coal owing to the rotation and are arranged on a helical line about the axis of rotation. It can be seen from FIG. 2 that an imaginary line, not shown in the figure, running through the centers of the picks makes a greater relix angle about the axis of the boring apparatus than the helix angles of the helical paths of the individual picks. As a result of this the cutting of the harder underlying stratum of the rock in general in which the apparatus is working, in the zone A is as shown in FIG. 4. In this case the pick 1 furthest to the front first cuts a groove 1 as shown in FIG. 4 and the groove is successively widened out as indicated by reference numerals 2 to 16 in the figure. As a result of this backward cutting of the groove to widen it out along the extent L there is a thrust along the axis of the hole towards the front. In the particular case shown the greater hardness of the underlying stratum with the boundary surface 105a means that there will be a greater forward thrust at the bottom of the boring apparatus than at the top, these unequal thrusts being represented by reference numerals 107a and 10717. This may also be conventionally expressed by the arrow 108a indicating reaction being placed higher than the forward thrust 109a due to the rod 103a as shown in the figure. As a result the boring apparatus is tipped in a saggital plane and runs back into the coal, leaving the softer stratum. If the top boundary 106a of the hole being produced should run into the boundary between the upper harder stratum 104a and the coal seam 101a the result will be that the thrust 1071? will become greater than the thrust 107a, and the boring apparatus will be tipped back into the coal seam.

In the embodiment of the invention as shown in FIG. 5 the boring apparatus 202 is mounted on a driving or boring rod 203. Boring picks shown diagrammatically and similar to those used in the preceding embodiment of the invention, 301-313 are mounted on the cylindrical outer face of the boring apparatus and are arranged to cut the coal to its fina1 dimension.

On the front face 200 of the boring apparatus we provide suitably mounted picks 314-329 arranged along two lines on parts 210 and 211 in such a manner that the cutting edges of the picks extend along lines whose radial projection on to an imaginary cylinder about the axis of the boring apparatus represents a double start helix while their projections on to a radial plane represent a spiral. The picks, which can be of a construction well known in the art and are therefore not shown in detail, have a rake angle.

The cutting tips of the picks can also be set to lie on two helicoidal faces. In order to facilitate the understanding of the invention a helicoidal face is shown in FIG. 9. In this case the generatrix is a straight line 401 which rotates about the axis 402, the angle between the two being a right angle so that a right helicoidal surface is produced. A helicoidal face produced by rotation through 180 is shown in perspective and denoted by reference numeral 407. The term helicoid or heilcoidal surface extends to cover cases in which the generatrix is curved or is a straight line not at a right angle to the axis of rotation.

FIG. 6 shows the front face 504 of a further embodiment of the invention which rotates about an axis 503 corresponding to the axis of rotation 212 of the previous embodiment to the invention. The boring apparatus is mounted centrally on a boring rod. The frame part 504 has two carriers 505 on which there are mounted curved segments 506 carrying teeth or picks 507 arranged so .4 that their cutting edges lie in a helicoidal surface, for instance in accordance with 407 indicated in FIG. 9.

The arrangement of the picks 507 on the carriers 506 is shown diagrammatically in FIG. 8. From this figure it can be seen that the bodies of the picks run towards the axis 503 of the apparatus and also are inclined some what to the rear.

In operation the rotation and forward feed of the boring apparatus causes the picks to generate a helicoidal cutting surface on the coal. The rate of feed can be arranged to be so great that the cutting means, that is to say the picks 507 exert a forward thrust similar to the action of a tap cutting a screw thread.

The further embodiment of the invention shown in FIG. 7 has a frame made in two sections arranged to rotate in opposite directions, 501 and 520, about the axis of the bore. The inner frame section has picks or other cutting tools mounted on it as shown in FIG. 6 while the outer section has two carriers 511 with flanges such as 512 on which picks are also carried. However the picks in the latter case and the flanges 512 correspond with helicoidal surfaces having the opposite hand to those of the helical surfaces with which the picks on parts 506 are mounted. The flanges 512 run from the outer edge 510a of the inner frame section and extend over the edge 510b of the outer segment.

In operation the speed of rotation of the outer section 510 is less than that of the inner one so that, by a suitable choice of the speed ratio there is a zero or minimum net rotational force on the boring apparatus. In order to allow for the different speeds of rotation the helical angles of the lines in which the cutting means, that is to say picks, are arranged on the inner section on the one hand and the outer section on the other hand can be different.

Instead of using fixed picks such as 314-329 in FIG. 5 or 507 FIG. 6 it is possible to use a cutting chain of the type well known in the art. If use is made of cutting rollers then the angle between the generatrix of the helical surface to which the cutting edges correspond and to the axis of rotation on the rear side of the generatrix can be such that the cutter rollers can be placed one behind the other.

In the embodiment of the invention shown in FIGS. 10 and 11 the frame comprises an outer hoop portion 601 coaxial with the axis of rotation, a central hub portion connoted by general reference numeral 602 and spokes 603 connecting the two together. On the hub 602 to one side of the spokes we provide a connecting means in the form of a conically threaded stem 604 while on the other side there is a drill 605 for boring a pilot hole in advance of the tools to be described. The apparatus further comprises spirally shaped tool support means 606 which extend from points of attachment to the hub 602 along two approximately spiral pads to attachment points on the hoop portion 601. The cutting means is in the form of separate rock cutting tools or picks 607 of the type used in cutting chains. Each cutting tool has a tungsten carbide cutting insert. The planes of the cutting edges of the tools converge generally towards the hub 602. The bodies of the tools slope in a direction towards the rear and towards the hub so as to keep them clear of the rock face to be cut. The boring apparatus further comprises cutting plates 608 with sharp edges conforming substantially to lines drawn through the tips of the other cutting tools 606. These lines can project it radially on to an imaginary cylinder coaxial with the axis of rotation produce helices while in an axial projection on to a radial plane they produce spirals.

The boring apparatus just described, which can be made with a diameter of 30 cm., can conveniently be used for boring holes upwards in coal.

What we claim is:

1. A boring head for cutting circular holes in rock comprising a circular body adapted to be rotated about an axis coinciding with the axis of the hole to be cut, said body having a relatively flat face, a pair of spirally shaped tool supporting segments projecting from said face, said segments extending from points near the body axis and spiralling in opposite directions to terminal points near the periphery of the body, the forward surfaces of said se ments being helicoidal with the highest points thereof disposed in the region of the body axis and the lowest points thereof disposed in the region of the body periphery, and cutting instrumentalities on said segments disposed in helicoidal fashion.

2. A boring head as claimed in claim 1 comprising an additional body coaxial with said first body and similarly structured and rotatable independently thereof, whereby one body may rotate in one direction and the other in the opposite direction.

3. A boring head as claimed in claim 1, in which said body comprises an outer hoop portion coaxial with the axis of rotation, a central hub portion, spokes connecting said hub portion with said hoop portion, connecting means attached to said hub portion on one side of said spokes, said segments extending from points of attachment to said hub portion on the other side of said spokes along approximately spiral paths to attachment points on said hoop portion, said cutting instrumentalities being in the form of separate rock cutting tools arranged on said segments, the planes of the cutting edges of said tools converging generally towards said hub portion, and the bodies of said tools sloping in the direction towards the rear and towards said hub portion, thereby to maintain them clear of the rock face to be cut.

References Cited UNITED STATES PATENTS 883,137 3/1908 Karns --385 X 2,201,219 5/1940 Bell 175391 X 2,711,888 6/1955 Robbins 29988 X 2,775,439 12/1956 McCarthy 175-391 X 2,798,707 7/1957 Kandle 29987 X 2,864,601 12/1958 McCarthy et a1. 29987 3,085,795 4/1963 Snipe 29987 3,174,801 3/1965 Owen 175-391 X FOREIGN PATENTS 585,709 2/ 1947 Great Britain.

NILE C. BYERS, 1a., Primary Examiner US. Cl. X.R. 175-394

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