Improvements in Core Boring Apparatus, Cutting Tools for the same, and in the Mode of Gripping and Raising Cores.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Improvements in Core Boring Apparatus, Cutting Tools for the
same, and in the Mode of Gripping and Raising Cores.
1, FRANCIS HARLEY DAVIS, of 29 Finks Buildings, Elizabeth Street, Melbourne,
in the Colony of Victoria, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention is designed to effect improvements of an important kind in boring
machinery, whereby I render practicable much greater economy of working
expenses, economy in the cost of the plant employed, and when prospecting or
testing country for deep leads or coal measures, the securing of a truer and more
reliable record of the strata as they are reached than is often arrived at by means
of the diamond drill or other known apparatus. In such apparatus the cores
obtained are often very incomplete, large portions having been ground away, and
washed to the surface, and there is no method of satisfactorily checking such losses
and obtaining a correct record of the thickness of scams of coal or other strata
pierced.
My improvements are extremely simple, and relate first to a set of cutting tools
(for rock and coal boring respectively), secondly to a chip cup apparatus for
debris, and thirdly to a method and apparatus (by the introducing sharp fragments
of hard rock or the like down the tubing and around the core, and by means of a
frustum of an inverted cone which forms the interior upper portion of the cutter)
whereby I am able as hereinafter set forth, without expense or uncertainty to cause
the core to be gripped broken off and raised with the rods from time to time as
required.
Referring now to the accompanying sheets of drawings which form a part of
this Specification, and in which the same letters of reference indicate like
parts:-
Figure 1 shows my apparatus in vertical elevation complete as it would appear
at work boring the earth's strata, the latter being shown in section.
Figure 2 shows in vertical middle section the same parts of the apparatus as in
Figure 1.
Figure 3 is a sectional plan of the boring rod and the chip cup with its
steadying pins.
Figure 4 is a sectional elevation of the reducing plug showing the boring rod
coupled to the same and showing the upper end of the core barrel and the base of
the chip cup.
Figure 5 is a sectional elevation showing the base of the core barrel and the
frustum of an inverted cone, formed in the upper portion of
portion is shown screwed into position.
Figure 6 shows my rock cutter, and Figure 7 my coal cutter both in vertical
elevation.
Figures 8 and 9 show respectively plan views from below of the said rock and
coal cutter.
Figure 10 shows a horizontal section of the rock cutter on the line X X in
Figure 6.
Referring to these figures in which Figures 1 and 2 are upon a smaller scale than
the other figures A shows a hollow boring rod and represents the lowermost of the
usual series of coupled tubes, which extend to the surface and are caused to rotate
when boring is in progress.
D
037

page_text: B shows a novel chip cup consisting of a plain cylinder or series of connecting
cylinders, and located above the core barrel, so that when in use its base is closed
and it forms an annular cup having a certain specific capacity hereafter stated. C is
a reducing plug or coupling, part of its length being shown screwed into the upper
end of the core barrel D, or it may be shrunk into and rivetted or otherwise
secured to the same. This piug has internally a female screw as shown into which
the lower end of A is screwed home to its seat as shown. The plug has also a
shoulder of the same diameter as the core barrel, which shoulder prevents the plug
going too far down. The base of the chip cup B is slipped down (and fits closely
over a part of C which projects above D) resting on the shoulder aforesaid. There
is a bayonet slot H in the projecting portion of C and an internally projecting pin I
near the base of the cup B, by which these parts are kept locked together when in
the bore. The base of the bayonet slot extends in the reverse direction to that in
which the tubes are rotated, so that there is no tendency for the cup to become
displaced. J, J, J, show pins at the upper extremity of the chip cup serving to
keep it with its sides parallel to the boring rod which passes through it. In F the
rock cutting bit there is a series of spiral grooves of wide pitch K, K, there being
for each cutting tooth one groove which is not merely a shallow depression to act
as a channel for water and finely divided debris, but is cut deeply as shown in
Figure 10 so as to allow large chips to ascend and also allow of gulleting the teeth
when worn. My cutter is novel, and by having the teeth in this shape and far
apart, the action is different from that of ordinary drills. Instead of pulverising
the rock into very fine parts, my cutter when slowly rotated under great pressure
bas the effect of removing large flakes which I call chips. I will again refer
to the cutter F in a later part of this Specification. In some cases I use vertical
grooves K' as shown by dotted lines in Figure 6 instead of spiral ones.
This apparatus is worked in the usual manner by rotating the series of hollow
rods A and thereby the core barrel D and the rock or coal cutting bit F or G,
water being at the same time forced through the interior of A and D to the bottom
of the bore, and where it rises up round the exterior of the tubing, as in the
working of diamond drills, and other hydraulic boring machines.
The water as it escapes under the gullets of the teeth of the cutter, and begins
to ascend, carries with it the chips and powdered particles of mineral matter as fast
as they are produced by the boring bit.
Now in all diamond and other hydraulic drilling machinery, the whole or almost
all of the cuttings or chips are caused to pass with the water up the bore to the
surface, and to do this these drills require extremely powerful special steam
pumps when any considerable depth is attained. Thus it is that the cost of drilling
at great depths with such drills, and the cost of plant, as well as the quantity of
water employed are all excessive. The weight of the rock cuttings held in the
water becomes at length so great, that a point may be reached where the influence
of gravity cannot be overcome by the process of pumping except at a practically
prohibitive expenditure of power. I proceed on totally different principles.
provide that the chips and debris shall never be carried up to the surface by the
ascending water, and instead of a powerful steam pump an ordinary hand pump
suffices for my apparatus, no matter how deep the bore may be, it being essential
to avoid having such powerful currents as I have referred to.
The current from my comparatively weak pump does not lift the debris far up
the bore, so that water from bores made with my apparatus reaches the surface
only slightly loaded with impurities.
I have found that the contrivance B renders my plan a success. B is a cylinder
(preferably a series of connectable cylinders) forming one long annular cup around
the lowest boring rod, and immediately above, and of uniform diameter with the
core barrel, and it has this essential characteristic which distinguishes it from al
other inventions and without which it would fail to answer the purpose for which
it is used, that it is approximately of such length as to be able to hold all the debris
which the cutter removes whilst filling the core barrel with core.

page_text: The object of having disconnectable sections is that they enable the cup to be
emptied without trouble when required. This rigid and lengthy cup (in practice
reaching with the apparatus I usually employ to a point over 40 feet above the
cutters, and almost filling the bore for that distance), also serves to keep the whole
boring apparatus true to its vertical line, a matter in respect to which other boring
apparatus is prone to give some trouble.
Having then provided such a cup which is definitely able to contain all the
debris aforesaid and having a jet of water no more powerful than is necessary to
carry the debris above the top of the chip cup, at which point the speed of the
current diminishes on account of the widening of the water space in the bore, the
result is that the chips fall into the cup, and fill it in regular order as they are
produced, thus making an inversed but accurate record of the strata passed through
and the larger the chips the more promptly they are disposed of by their falling
into the cup, whereas in cases where the chips are forced to the surface the larger
the chips the greater is the power needed to dispose of them.
When my apparatus is caused to cease boring and there is a length in the core
barrel ready to be drawn, I cease pumping almost immediately, as in two or three
minutes the last of the chips will have been lodged in the cup. In the case of the
diamond drill in deep bores, the pumping must go on, often for an hour till the
greater part of the debris has been washed out, and even then there is often enough
fine mineral matter left in the bore to be a source of trouble under various well
known circumstances. Such is not the case with the apparatus I use which leaves
the bore practically clean and free from debris. As soon as my tubes are drawn I
empty the various sections of the chip cup, keeping the strata in order and also
empty the core barrel and check the core by the cuttings. If the core is perfect
there will be a definite proportion, such as 1 lb. of core to 2 lbs. of cuttings, and
the various kind of minerals in both core and cup will closely correspond.
Any discrepancy in the core can be detected and the extent calculated by noting
to what extent the contents of the core and the cup depart from the proper definite
proportions. By noting to what extent the respective contents of cup and barrel
depart from these conditions as to kind and quantity, it will be known to what
extent the cores fail to give a true and complete record of the strata, as happens
when one length of core rides or grinds upon another length beneath it.
It will be seen that the rock cutter F is of peculiar and novel construction, and
as it produces large chips would be impracticable in deep boring apparatus
unprovided with my chip cup. It is composed of a cylindrical piece of steel with
large teeth cut in the end as shown in Figure 6, these teeth being of sufficient
length (about 2 inches) to make it an easy matter to draw them out and dress
them upon an anvil like an ordinary pick point. When these teeth wear short a
portion of the gullet can be cut away, which will renew the length again and again
as long as the cylinder shall last.
The spiral grooves K or the vertical grooves K' are for a twofold purpose viz. ;
to make more clearance for the chips to flow upwards and to make the metal
lighter to cut out when gulleting. These teeth which may be any even number
preferably six but not less are set in and out alternately like saw teeth; the inside
set cuts the rock so as to leave free passage for the water between the core barrel
and the core, while the outside set cuts clearance for the whole apparatus to work
freely, and to allow water and chips to ascend to and enter the top of the cup.
Thus the spaces between the respective edges of the bore and the core, and the
cutter form the water ways referred to. In Figure 7 a bit G to cut seams of coal
is shown it being a modification of and interchangeable with the rock cutter F,
the machine would not be complete without it, as when coal is reached the coarse
teeth of G would fracture the core and destroy it. G is made of a steel cylinder,
the bottom end being cut into six sections set in and out alternately as already
described and as shown in Figure 7 each section consisting not of one tooth as in F
but of a number of fine saw teeth. The slots between the sections allow free
egress for the water, being a modification of the gullets in F, and vertical

page_text: grooves K in G take the place of the spiral grooves in F. I have now to describe
the simple method by which I break off and raise cores to the surface, and which
is applicable to diamond and other drilling apparatus.
When the boring has ceased I preferably take some quartz rock and crush it to
about the size of peas; this produces fragments of great hardness with sharp
edges, and these I drop from above down the inside of the coupled tubes A,
whereby they fall into the core barrel D and around the core. According to the
sizes and shapes of the fragments they find a bed at different parts within the core
tube, but principally between the core and inversely coned sides N of the interior
of the upper portion of the cutter F or G, at which part the wedging action is
most powerful.
A revolution or two of the tubing is then sufficient to embed and wedge the
edges of the fragments so firmly into the core and between the latter and the barrel
and the part N that no other gripping appliance whatever is necessary. By the
revolution last named the core is often broken off at the base but if not, it is
broken off or torn up by lifting and the whole of the rods being then raised, the
core will come up to the surface firmly gripped within its barrel. In carrying out
my said method of gripping and raising cores, any suitable substitute for quartz
rock may of course be employed.
By doing without the gripping arrangements hitherto used, and by gripping
cores in the manner described by me, I am enabled to avoid the necessity of
cutting away a wide annulus around the core, as is done where it is necessary to
give clearance for the space required for gripping appliances to work in. The
importance of this will be clear since the less debris there is cut away around the
core, the faster and cheaper the boring will be done. An inspection of the cores
resulting from my boring apparatus will disclose great freedom from spiral
groovings, the advantage of which is obvious. I procure this result by using
heavy pressure and comparatively slow rotation whereby the lashing that produces
the groovings is avoided.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In boring machinery of the kind described a chip cup, located about the
core barrel, and constructed substantially as and for the purposes set forth.
2. In boring machinery, a rock cutter such as F constructed substantially as and
for the purposes set forth.
3. In boring machinery, a cutter such as G for coal or the like, constructed
substantially as and for the purposes set forth, and as illustrated.
4. In boring machinery, the general arrangement and combination of the boring
rods as A, chip cup as B, reducing plug as C, and the core barrel as D substantially
as and for the purposes set forth, and as illustrated.
5. In boring machinery, the general combination and arrangement of core
barrel as D with an inversely coned surface as N, substantially as and for the
purposes set forth.
6. In boring machinery operations, the mode herein set forth of gripping cores,
and enabling them to be raised by means of fragments of hard material introduced
from above substantially as described.
Dated this 14th day of January 1895.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.