A ROTATING DRY DRILLING BIT

OUTIL DE FORAGE A SEC ROTATIF

English Abstract

A rotating dry drilling bit for low thrust drilling of an annular bore hole into a body of rock and obtaining an extremely small diameter core sample comprises a bit crown moulded to the end of an annular steel body. The bit crown comprises a plurality of radially extending channels and a plurality of evenly spaced radially extending cutting blades surrounding an annulus. The bit crown is a hard metal matrix formed onto the bottom end of the annular steel body using a powdered metallurgy process. Embedded within each cutting blade are natural and synthetic diamonds. A reverse auger mechanism within the annulus removes cuttings from the annulus and the surface of the bit crown.

French Abstract

Trépan rotatif de forage à sec pour le forage à faible poussée d'un trou de forage annulaire dans un corps rocheux et pour l'obtention d'une carotte d'un diamètre extrêmement petit, comprenant une couronne moulée à l'extrémité d'un corps annulaire en acier. La couronne comprend plusieurs canaux s'étendant radialement et plusieurs lames de coupe s'étendant radialement qui sont disposées à intervalles réguliers autour d'un anneau. La couronne est une matrice de métal dur formée sur l'extrémité inférieure du corps annulaire en acier par un procédé de métallurgie des poudres. Des diamants naturels et synthétiques sont intégrés dans chaque lame de coupe. Un mécanisme à tarière inversée à l'intérieur de l'anneau retire les déblais de forage de l'espace annulaire et de la surface de la couronne.

Claims

CLAIMS
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A rotating dry drilling bit for drilling an annular bore hole into a body
of rock and
obtaining a core sample from said body of rock, said rotating dry drilling bit
comprising:
a. an annular steel body having a first annulus, a first inside diameter, a
bottom end
and a top end, said top end adapted for coupling with a rotating drill string,
said drill
string having an second annulus with a second inside diameter;
b. a bit crown mounted to said annular steel body bottom end, wherein said bit
crown
has a top end and a bottom end and comprises:
i. a third annulus having a third inside diameter, a bottom rim and a top rim,
said third annulus extending through said bit crown, wherein the third
annulus is co-axial with said first and second annuli and adapted to receive
and pass said core sample to the annular steel body first annulus and hence
to the drill string second annulus;
ii. a bit head having a radial profile for rotatively cutting into said body
of rock
thereby forming the core sample and creating cuttings;
iii. a radial outer face integral to and above said bit head, said radial
outer face
having a vertical profile and adapted for stabilizing the bit head against
angular deviation and gauging said annular bore hole;
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iv. a plurality of radially extending channels formed therein and evenly
spaced
thereabout and adapted for carrying said cuttings away from the bit head;
v. a plurality of radially extending cutting blades formed therein and evenly
spaced thereabout wherein each one of said plurality of radially extending
cutting blades is separated by one of said plurality of radially extending
channels; and,
c. a transition zone adapted for receiving the cuttings from the plurality of
channels.
2. The dry drilling bit as claimed in claim 1, wherein said annular steel body
is machined
from C12L14 steel.
3. The dry drilling bit as claimed in claim 2 wherein the bit crown is a hard
metal matrix
formed onto the bottom end of the annular steel body using a powdered
metallurgy
process.
4. The dry drilling bit as claimed in claim 3, wherein the radial outer face
includes a
plurality of vertically oriented and parallel splines embedded therein, each
of said
splines having a radial surface.
5. The dry drilling bit as claimed in claim 4, wherein said third annulus top
rim is
characterized by a projection having a inwardly oriented tip thereby defining
the third
annulus top rim diameter from said tip to the opposite side of the rim to the
diameter of
the core sample.
2

6. The rotating dry drilling bit as claimed in claim 5, wherein said
projection applies
tension to the core sample causing it to separate from the body of rock.
7. The rotating dry drilling bit as claimed in claim 6, wherein each radially
extending
cutting blade of said plurality of radially extending cutting blades has a
bottom tip and a
top tip, and wherein first bottom tip extends radially downward into the third
annulus a
predetermine distance.
8. The rotating dry drilling bit as claimed in claim 7, wherein each radially
extending
channel of said plurality of radially extending channels has a bottom tip and
a top tip,
and wherein said channel bottom tip terminates at said bottom rim.
9. The rotating dry drilling bit as claimed in claim 8, wherein a junk pocket
is formed
above the projection and between the projection and the bottom of the adjacent
radially
extending cutting blade, said junk pocket adapted for collecting cuttings
within the third
aperture.
10. The rotating dry drilling bit as claimed in claim 9 further including
means for removing
cuttings from the third aperture.
11. The rotating dry drilling bit as claimed in claim 10, wherein said means
for removing
cuttings comprises:
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a. a plurality of radially spaced auger blades fixed to the bottom inside
surface of the
third annulus, wherein each of said plurality of radially spaced auger blades
has an
attacking surface, a bottom end and a top end, and further wherein the bottom
end of
each of said plurality of radially spaced auger blades is adjacent to a
corresponding
bottom tip of each of said plurality of radially extending cutting blades, and
wherein
each auger blade of said plurality of radially spaced auger blades is oriented
diagonally across the width of each radially extending channel of said
plurality of
radially extending channels; and,
b. a row of evenly spaced abrasive elements adjacent and parallel to the
attacking
surface of each blade of said plurality of radially spaced auger blades;
so that in operation, as the dry drill bit is rotating, the auger blades sweep
the cuttings
from the third annulus into an adjacent radially extending channel for
carriage by
centrifugal force away from the bit head.
12. The rotating dry drilling bit as claimed in claim 11, wherein each
radially extending
cutting blade of the plurality of radially extending cutting blades has a
blade surface
area diminishing tapered width from the bottom tip to the top tip thereof.
13. The rotating dry drilling bit as claimed in claim 12, wherein each
radially extending
channel of the plurality of radially extending channels has a channel surface
area and a
diminishing tapered width from the top tip to the bottom tip thereof.
4

14. The rotating dry drilling bit as claimed in claim 13, wherein each
radially extending
cutting blade of the plurality of radially extending cutting blades and each
radially
extending channel of the plurality of radially extending channels have a
diagonal
orientation conforming to the direction of rotation of the rotating dry drill
bit.
15. The rotating dry drilling bit as claimed in claim 14, wherein said blade
surface is raised
above the channel surface thereby creating blade surface opposite side walls
comprising
a blade surface leading side wall and a blade surface lagging side wall.
16. The rotating dry drilling bit as claimed in claim 15, wherein said blade
surface leading
side wall and said blade surface lagging side wall are angled at a
predetermined angle
towards the direction of rotation of the dry drilling bit.
17. The rotating dry drilling bit as claimed in claim 16, wherein a plurality
of abrasive
elements is inserted into the blade surface.
18. The rotating dry drilling bit as claimed in claim 17, wherein said
plurality of abrasive
elements comprise natural diamonds.
19. The rotating dry drilling bit as claimed in claim 17, wherein said
plurality of abrasive
elements comprises synthetic diamonds.
20. The rotating dry drilling bit as claimed in claim 17, wherein the
plurality of abrasive
elements comprises a combination of natural and synthetic diamonds.

21. The rotating dry drilling bit as claimed in claim 17, 18 and 19, wherein a
row of
abrasive elements is inserted into said radial surface of each of said
splines.
22. A rotating dry drilling bit for drilling an annular bore hole into a body
of rock and
obtaining a core sample from said body of rock, said rotating dry drill bit
comprising:
a. an annular steel body having a first annulus, a first inside diameter, a
bottom end
and a top end, said top end adapted for coupling with a rotating drill string,
said drill
string having an second annulus with a second inside diameter;
b. a bit crown comprising a hard metal matrix formed onto said bottom end of
said
annular steel body using a powdered metallurgy process, wherein said bit crown
has
a top end and a bottom end and comprises:
i. a third annulus having a third inside diameter, a bottom rim and a top rim,
said third annulus extending through said bit crown, wherein the third
annulus is co-axial with said first and second annuli and adapted to receive
and pass said core sample to the annular steel body first annulus and hence
to the drill string second annulus;
ii. a bit head having a radial profile for rotatively cutting into the body of
rock
thereby forming the core sample and creating cuttings;
iii. a plurality of tapered radially extending channels formed therein and
evenly
spaced thereabout and adapted for carrying said cuttings away from the bit
head;
iv. a plurality of tapered radially extending cutting blades formed therein
and
evenly spaced thereabout wherein each one of said plurality of radially
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extending cutting blades is separated by one of said plurality of radially
extending channels; and,
v. a plurality of radial outer faces adjacent to and above said bit head,
wherein:
1. each radial outer face of said plurality of radial outer faces is integral
to an adjacent radially extending cutting blade;
2. the plurality of radial outer faces is adapted for stabilizing the bit
head against angular deviation and gauging said bore hole;
3. each radial outer face of said plurality of radial outer faces comprises
a plurality of vertically oriented and parallel splines embedded
therein;
4. each radial outer face of said plurality of radial outer faces deviates a
predetermined angle from its adjacent tapered radially extending
cutting blade; and,
c. a transition zone adapted for receiving the cuttings from the plurality of
tapered
radially extending channels, wherein said transitional zone is integral to and
above
the bit crown and comprises a vertical surface extending at a predetermined
angle
from the top of the radial outer face to the surface of the annular steel
body, so that
the transitional zone receives cuttings from the plurality of channels and
transfers
them to an auguring means located above the transitional zone for transport
out of
the bore hole.
23. The dry drilling bit as claimed in claim 22, wherein said third annulus
top rim is
characterized by a projection having a variable length and an inwardly
oriented tip
extending a predetermined distance into the third annulus thereby reducing the
third
7

annulus top rim diameter from said tip to the opposite side of the rim to the
diameter of
the core sample, wherein said projection is in sliding contact with the core
sample,
applies tension to the core sample thereby causing it to separate from the
body of rock
and gauges the core sample.
24. The rotating dry drilling bit as claimed in claim 23, wherein each tapered
radially
extending cutting blade of said plurality of tapered radially extending
cutting blades has
a first bottom tip and a second top tip, and wherein said first bottom tip
extends
horizontally across the third annulus a distance equal to said predetermine
distance.
25. The rotating dry drilling bit as claimed in claim 24, wherein each tapered
radially
extending channel of said plurality of tapered radially extending channels has
a bottom
tip and a top tip, and wherein said channel bottom tip terminates at said
bottom rim.
26. The rotating dry drilling bit as claimed in claim 25, wherein the diameter
of the core
sample is determined by the distance between the opposite top tips of the
plurality of
tapered radially extending cutting blades.
27. The rotating dry drilling bit as claimed in claim 26, wherein a junk
pocket is formed
above the projection and between the projection and the bottom of the adjacent
tapered
radially extending cutting blade, said junk pocket adapted for collecting
cuttings within
the third aperture.
8

28. The rotating dry drilling bit as claimed in claim 27 further including
means for
removing cuttings from the third aperture.
29. The rotating dry drilling bit as claimed in claim 28, wherein said means
for removing
cuttings from the third aperture comprises:
a. a plurality of radially spaced auger blades diagonally oriented counter-
rotationally
and fixed to the bottom inside surface of the third annulus, wherein each of
said
plurality of radially spaced auger blades has an attacking surface, a bottom
end and
a top end, and further wherein the bottom end of each of said plurality of
radially
spaced auger blades terminates at the top rim of the third annulus; and,
b. a row of evenly spaced abrasive elements adjacent and parallel to the
attacking
surface of each blade of said plurality of radially spaced auger blades
so that in operation, as the dry drill bit is rotating, said row of evenly
spaced abrasive
elements crushes the cuttings whereupon each radially spaced auger element of
the
plurality of radially spaced auger elements sweeps the cuttings from the third
annulus
into an adjacent radially extending channel for carriage by centrifugal force
away from
the bit head.
30. A rotating dry drilling bit for drilling an annular bore hole into a body
of rock and
obtaining a core sample from said body of rock, said rotating dry drill bit
comprising:
9

a. an annular steel body having a first annulus, a first inside diameter, a
bottom end
and a top end, said top end adapted for coupling with a rotatable drill
string, said
drill string having an second annulus with a second inside diameter;
b. a bit crown comprising a hard metal matrix formed onto said bottom end of
said
annular steel body using a powdered metallurgy process, wherein said bit crown
has
a top end and a bottom end and comprises:
i. a third annulus having a third inside diameter, a bottom rim and a top rim,
said third annulus extending through said bit crown, wherein the third
annulus is co-axial with said first and second annuli and adapted to receive
and pass said core sample to the annular steel body first annulus and hence
to the drill string second annulus;
ii. a bit head having a radial profile for rotatively cutting into the body of
rock
thereby forming the core sample and creating cuttings;
iii. a plurality of radially extending channels formed therein and evenly
spaced
thereabout, said channels having a surface area, a bottom tip and a top tip
and adapted for carrying said cuttings away from the bit head, wherein said
plurality of radially extending channels have a constant width from said top
tip to said bottom tip;
iv. a plurality of radially extending cutting blades formed therein and evenly
spaced thereabout, said plurality of radially extending cutting blades having
a surface area, a bottom tip and a top tip, wherein the width of each cutting
blade of the plurality of cutting blades is consistent from said bottom tip to
said top tip, wherein each one of said plurality of radially extending cutting

blades is separated by one of said plurality of radially extending channels;
and,
v. a plurality of radial outer faces adjacent to and above said bit head,
wherein:
1. each radial outer face of said plurality of radial outer faces is integral
to an adjacent radially extending cutting blade;
2. the plurality of radial outer faces is adapted for stabilizing the bit
head against angular deviation and gauging said bore hole;
3. each radial outer face of said plurality of radial outer faces comprises
a plurality of vertically oriented and parallel splines embedded
therein; and,
c. a transition zone adapted for receiving the cuttings from the plurality of
tapered
radially extending channels, wherein said transitional zone is integral to and
above
the bit crown and comprises an vertical surface extending at a predetermined
angle
from the top of the radial outer face to the surface of the annular steel
body, so that
the transitional zone receives cuttings from the plurality of channels and
transfers
them to an auguring means located above the transitional zone for transport
out of
the bore hole.
31. The rotating dry drilling bit as claimed in claim 30, wherein each one of
the plurality of
radially extending cutting blades and each one of the radially extending
channels is
oriented diagonally at an predetermined angle away from the vertical and
towards the
direction of rotation.
11

32. The dry drilling bit as claimed in claim 31, wherein said third annulus
top rim is
characterized by a projection having a variable length and an inwardly
oriented tip
extending a predetermined distance into the third annulus thereby defining the
third
annulus top rim diameter from said tip to the opposite side of the rim to the
diameter of
the core sample, wherein said projection is in sliding contact with the core
sample,
applies tension to the core sample thereby causing it to separate from the
body of rock
and gauges the core sample.
33. The rotating dry drilling bit as claimed in claim 32, wherein each tapered
radially
extending cutting blade of said plurality of tapered radially extending
cutting blades has
a bottom tip and a top tip, and wherein said bottom tip extends horizontally
across the
third annulus a distance equal to said predetermine distance.
34. The rotating dry drilling bit as claimed in claim 33, wherein each tapered
radially
extending channel of said plurality of tapered radially extending channels has
a bottom
tip and a top tip, and wherein said channel bottom tip terminates at said
bottom rim.
35. The rotating dry drilling bit as claimed in claim 34, wherein the diameter
of the core
sample is determined by the distance between the opposite top tips of the
plurality of
tapered radially extending cutting blades.
36. The rotating dry drilling bit as claimed in claim 35, wherein a pocket is
formed above
the projection and between the projection and the bottom of the adjacent
tapered
12

radially extending cutting blade, said pocket adapted for collecting cuttings
within the
third aperture.
37. The rotating dry drilling bit as claimed in claim 36 further including
means for
removing cuttings from the third aperture.
38. The rotating dry drilling bit as claimed in claim 37, wherein said means
comprises:
a. a plurality of radially spaced auger blades diagonally oriented counter-
rotationally
and fixed to the bottom inside surface of the third annulus, wherein each of
said
plurality of radially spaced auger blades has an attacking surface, a bottom
end and
a top end, and further wherein the bottom end of each of said plurality of
radially
spaced auger blades terminates at the top rim of the third annulus; and,
b. a row of evenly spaced abrasive elements adjacent and parallel to the
attacking
surface of each blade of said plurality of radially spaced auger blades;
so that in operation, as the dry drill bit is rotating, said row of evenly
spaced abrasive
elements crushes the cuttings whereupon each radially spaced auger element of
the
plurality of radially spaced auger elements sweeps the cuttings from the third
annulus
into an adjacent radially extending channel for carriage by centrifugal force
away from
the bit head.
39. A rotating dry drilling bit for drilling an annular bore hole into a body
of rock and
obtaining a core sample from said body of rock, said rotating dry drill bit
comprising:
13

a. an annular steel body having a first annulus, a first inside diameter, a
bottom end
and a top end, said top end adapted for coupling with a rotatable drill
string, said
drill string having an second annulus with a second inside diameter;
b. a bit crown comprising a hard metal matrix formed onto said bottom end of
said
annular steel body using a powdered metallurgy process, wherein said bit crown
has
a top end and a bottom end and comprises:
i. a third annulus having a third inside diameter, a bottom rim and a top rim,
said third annulus extending through said bit crown, wherein the third
annulus is co-axial with said first and second annuli and adapted to receive
and pass said core sample to the annular steel body first annulus and hence
to the drill string second annulus;
ii. a bit head for rotatively cutting into the body of rock thereby forming
the
core sample and creating cuttings, said bit head comprising a plurality of
cutting elements having a cylindrical shape, a diameter, a thickness, a flat
circular attacking face having a circumference and a lagging face, wherein
said attacking face has a cutting edge which will engage the body of rock
about said circumference;
iii. an opening between each of said plurality of cutting elements, wherein
said
opening is adapted to remove cuttings away from the bit head;
iv. a plurality of radial outer faces integral to the bit crown and disposed
above
the plurality of cutting elements, wherein said outer faces are adapted for
stabilizing the bit head against angular deviation and gauging said bore hole;
and,
14

c. a transition zone adapted for receiving said cuttings from the openings for
transport
away from the bit crown.
40. The rotating dry drilling bit as claimed in claim 39, wherein the cutting
elements are
oriented at a predetermined rake angle so that each of said attacking faces is
angled to
attack the body of rock.

Description

CA 02509854 2005-06-13
A ROTATING DRY DRILLING BIT
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of drill bits for core
boring and more
particularly to a rotating dry drilling bit for low thrust boring operations
in very remote locations.
Core boring or "diamond drilling" is well known in the fields of geophysics,
mineral and
hydrocarbon exploration. Generally a drill bit is attached to the end of a
rotating string. The drill
bit comprises a bit crown with cutting blades including abrasive elements,
such as natural and/or
synthetic diamonds, impregnated therein. The know art discloses a variety of
core drill bits for
high thrust drilling operations such as is necessary to penetrate thick rock
layers. The friction
generated by high thrust drilling also necessitates the use of drilling mud to
lubricate and cool the
drill bit. United States Patent 4,760,888 "Drill Bit for Core Boring" issued
to Saito on August 2,
1988 and United States Patent 6,474,425 "Asymmetric Diamond Impregnated Drill
Bit" issued to
Truax et al on November 5, 2002 are exemplary. These drill bits are robust and
well suited to high
thrust drilling and coring operations that are land based or extend from a
deep see drilling rig and
obtain core samples that are meters long and centimeters in diameter.
However, with the advent of extreme depth submarine and remote extra-
terrestrial
exploration, high thrust drilling is not practical because of the weight
restrictions that such
exploration entails and the impracticality of using a lubricating and cooling
fluid. Drilling
equipment for submarine and extra-terrestrial must be small and light for
transportation and
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CA 02509854 2005-06-13
therefore low powered. Such low powered drilling equipment is unable to
utilize the large scale
heavy drill bits used in terrestrial drilling applications.
Therefore there is a need for a coring drill bit that is able to be used dry
in low thrust
drilling in extremely remote locations.
SUMMARY OF THE INVENTION
A principal object of the present invention is the provision of coring bit
that is able to be
used in extremely remote locations with low thrust drilling equipment.
Another object of the present invention is the provision of a coring bit that
can be used dry.
Still another object of the present invention is the provision of a coring bit
that is able to
provide a core sample that is small and light and can be transported for
analysis.
The above and other objects of the present invention will become apparent from
a reading
of the following description taken in conjunction with the accompanying
drawings which illustrate
the preferred embodiments thereof.
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CA 02509854 2005-06-13
The objects of the present invention are satisfied by providing a rotating dry
drilling bit for
drilling an annular bore hole into a body of rock and obtaining a core sample
from the body of
rock. The drill bit comprises an annular steel body having a first annulus, an
inside diameter, a
bottom end and a top end. The top end is adapted for coupling with a rotating
drill string. The drill
string has a second annulus with a second inside diameter. A bit crown is
mounted to the annular
steel body bottom end. The bit crown has a top end and a bottom end and
includes a third annulus
having an inside diameter, a bottom rim and a top rim. The third annulus
extends through the bit
crown and is adapted to receive and pass the core sample to the second annulus
of the drill string.
The bit crown includes a bit head having a radial profile for cutting into the
body of rock thereby
forming the core sample and creating cuttings. The bit head also includes a
radial outer face
having a vertical profile and adapted for stabilizing the bit head against
angular deviation and
gauging the annular bore hole. Within the radial outer face is included a
plurality of vertically
oriented and parallel splines for stabilizing the bit head in the bore hole.
The bit crown further
includes a plurality of radially extending channels and cutting blades formed
therein and evenly
spaced thereabout. The cutting blades are equipped with abrasive elements that
comprise natural
diamonds such as 50SPC AAAA grade natural diamonds combined with synthetic
diamond
crystals impregnated into the volume of the bit crown. In another embodiment
of the invention the
abrasive elements comprise synthetic diamonds in the form of thermally stable
polycrystalline
diamond elements plus synthetic diamond crystals impregnated into the volume
of the bit crown.
A row of abrasive elements combining natural diamonds 75 SPC AAAA grade
natural diamonds
and 75SPC Kicker grade natural diamonds or, alternatively, synthetic diamonds
is also inserted
into each of the surfaces of each of the splines.
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CA 02509854 2005-06-13
A transition zone adapted for receiving the cuttings from the plurality of
channels is also
provided. The steel body is machined from C 12L 14 steel. The bit crown is a
hard metal matrix
formed onto the bottom end of the steel body using a powdered metallurgy
process. A reverse
augering mechanism is included within the drill bit aperture to remove
cuttings from the drill bit.
Other embodiments of the invention are disclosed herein having bit crowns
having differing
geometries.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a cross-sectional side view of a first embodiment of the
invention.
Figure 2 is a bottom view of the first embodiment of the invention.
Figure 3 is an elevation view of a first embodiment of the invention.
Figure 4 is the same view as in Figure 1.
Figure 5 is a sectional side view of a second embodiment of the invention.
Figure 6 is a bottom view of a second embodiment of the invention.
Figure 7 is an elevation view of a second embodiment of the invention.
Figure 8 is the same view as Figure 5.
Figure 9 is a cross-sectional side view of a third embodiment of the
invention.
Figure 10 is a bottom view of a third embodiment of the invention.
Figure 11 is an elevation view of a third embodiment of the invention.
Figure 12 is the same view as Figure 9.
Figure 13 is a cross-sectional side view of a fourth embodiment of the
invention.
Figure 14 is an elevation view of a fourth embodiment of the invention.
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CA 02509854 2005-06-13
Figure 15 is a bottom view of a fourth embodiment of the invention.
DETAIELD DESCRIPTION
A First Embodiment
Referring now to Figure 1, there is shown in a cross-sectional side view a
first embodiment
of our invention identified generally as (10). Our invention comprises a
rotating dry drilling bit for
drilling an annular bore hole into a body of rock and obtaining a core sample
from the body of
rock. What is unique about our drill bit is that it is used dry, that is,
without any drilling fluids or
mud to lubricate the drilling process and carry the cuttings away from the
drill head. What is also
unique about our dry drill bit is that it is used to obtain cylindrical core
samples having diameters
which are very small, that is, for example, between 5mm and 15mm.
Dimensions provided throughout this detailed description related to a
particular
embodiment of the invention. A person skilled in the art would readily
understand that these
dimensions can vary depending on the operational requirements of the drilling
project.
The rotating dry drilling bit of our invention is about 31.4mm long and
comprises an
annular steel body (12) having a first annulus (14), a cylindrical wall (16)
having an inner surface
(18), a first inside diameter (20) of about 12.4mm, an axis (22), a bottom end
(24) and a top end
(26). The top end (26) of the annular steel body (12) is adapted for coupling
with a co-axial
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CA 02509854 2005-06-13
rotatable drill string not shown in this diagram. The drill string has a
second annulus with a second
inside diameter equal to inside diameter (20).
There is a co-axial bit crown shown generally as (28) which is about 30mm in
diameter and
mounted to the annular steel body bottom end (24) over integral anchors (25)
and (27). The bit
crown can have different geometries as shown in other embodiments of our
invention.
In this embodiment, the bit crown has a top end (30) and a bottom end (32) and
comprises a
third annulus (34) having a third inside diameter (36) of about 10.13mm, a
bottom rim (38) and a
top rim (40). The third annulus (34) extends through the bit crown and is co-
axial with the first
(14) and second annuli. The third annulus (34) is further adapted to receive
and pass the core
sample to the annular steel body first annulus (14) and hence to the drill
string second annulus.
The radius (44) of the bit crown is about 6mm and determines the amount of
point loading on the
bottom end (32) of the bit crown. The radius of bit crown in this embodiment
ensures that a high
loading is achieved to commence the core as well as encouraging cuttings to
exit through the
channels (50) (Figure 2) away from the bit crown as more fully explained
below. There is a bit
head (42) also called a"kerf' which is the surface area of the drill which
experiences the greatest
thrust during drilling operations. By design, the width of the kerf should be
as narrow as possible
in order to maximize the point loading on the cutting surfaces of the drill
bit. In our design, the
geometry of the kerf is optimized to obtain a maximum point load upon the bit
during low thrust
drilling. Such low thrust drilling might be necessary on an extraterrestrial
surface such as the
moon or Mars. Another factor which must be taken into consideration when
designing the
geometry of the kerf is the frequency with which the drill bit must be
replaced. Understandably, in
remote locations, it may be impossible to change the drill head. Hence, a
geometry which ensures
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CA 02509854 2005-06-13
long life of the bit head is desirable for such applications. One factor which
influences the size of
the kerf is the size of the core sample desired. The kerf of our invention is
guided by the equation
with reference to Figure 1:
K = 0.5(S) +X+2T - (0.5(C)), wherein
K = minimum kerf (Item 42)
C= core sample outside diameter (Item 36)
S = core sample capture mechanism outer diameter (Item 40)
X = loose fit clearance room (nominal 0.5mm to 1 mm)
T = depth of thread connecting the drill bit to the drill string.
A = crown auger depth (Item 51 Figure 2)
The bit crown includes a plurality of radial outer faces (46). The radial
outer faces (46)
have a vertical profile and are about 5mm high. They are adapted for
stabilizing the bit head (28)
against angular deviation as well as gauging the annular bore hole.
Referring now to Figure 3, there is shown, in side view, the drill bit (10).
Within each of
the radial outer faces (46) there is embedded a plurality of vertically
oriented and parallel splines
(56). Each of the splines has a surface (58), a top end (60) and a bottom end
(62).
Referring back to Figure 2, there is illustrated a bottom view of the bit
crown (28) showing
the top rim (38) of third annulus (34). Formed within the within the bit crown
(28) is a plurality of
evenly spaced radially extending channels (50) adapted for carrying cuttings
away from the bit
head (28) by centrifugal force as the drill bit rotates. It is necessary to be
able to clean the kerf of
7

CA 02509854 2005-06-13
cuttings as the drill operates to avoid glassing and over grinding the
cuttings which greatly reduces
the efficiency of the drill. However, under low thrust conditions, some
cuttings present under the
kerf will act to lubricate the drill bit. In operation, the channels rotate
with the drill and act as an
auger to remove cuttings away from the bit head by centrifugal forces. The
depth (51) and profile
of the channels are dependent upon the speed of the drill (RPMs) and the
volume of cuttings
anticipated. A higher drill speed will tend to increase the efficiency of the
channels in removing
cuttings away from the bit head.
As well, the bit crown (28) has a plurality of evenly spaced radially
extending cutting
blades (52). Each one of the radially extending cutting blades (52) is
separated by one of the
radially extending channels (50). In the embodiment illustrated in Figures 1
and 2, there are six
cutting blades and six channels although there may be more or less of each.
Referring to Figure 2 and Figure 3, each radially extending cutting blade (52)
has a blade
surface area generally indicated at (100). Each blade has an increasing
tapered width from the
bottom end (70) of the blade to the top end (72) of the blade. As well, each
radially extending
channel (50) has a channel surface area generally shown as (102) and an
increasing tapered width
from the bottom end (76) or inlet of the channel of about 2.5mm to the top end
(78) or outlet of the
channel of about 6.3mm. The surface area (100) of each blade (52) is greater
than the surface area
(102) of each channel (50) in this embodiment. However, this is not the case
in all embodiments
and is dependent upon the requirements of the drilling project.
As shown in Figure 3, each radially extending cutting blade (50) and each
radially
extending channel (52) has a diagonal orientation at an angle (55) conforming
to the direction of
8

CA 02509854 2005-06-13
rotation (110) of the rotating dry drill bit. The diagonal orientation is
generally about 24 degrees
from the vertical axis (22) but the angle may be fore or less than 24 degrees.
As noted above, this
angled configuration promotes the auguring action of the drill bit to remove
cuttings from the drill
bit.
Referring still to Figures 2 and 3, the blade surface (100) is raised above
the channel
surface (102) a predetermined distance (51) (about lmm in this embodiment)
thereby creating
blade surface opposite side walls comprising a blade surface leading side wall
(112) and a blade
surface lagging side wall (114). As shown in Figure 2, Section A-A, the blade
surface leading side
wall (112) and the blade surface lagging side wall (114) are angled at a
predetermined angle (116)
towards the direction of rotation of the dry drilling bit. The angle (116) is
about 24 degrees from
the horizontal (117) as shown in Section A-A but it may be more or less than
24 degrees. A
plurality of abrasive elements (118) is embedded into the blade surface
providing a relief of about
0.3mm above the surface of the blade. In one embod'unent of the invention the
abrasive elements
comprise natural diamonds such as 50SPC AAAA grade natural diamonds and
synthetic diamond
crystals impregnated into the volume of the bit crown. In another embodiment
of the invention the
abrasive elements comprises synthetic diamonds in the form of thermally stable
polycrystalline
diamond elements plus synthetic diamond crystals impregnated into the volume
of the bit crown.
A row of abrasive elements (120), combining natural diamonds 75 SPC AAAA grade
natural
diamonds and 75SPC Kicker grade natural diamonds or, alternatively, synthetic
diamonds is also
inserted into each of the surfaces of each of the splines (56).
Referring back to Figure 1, there is a transition zone (54) that is adapted
for receiving the
cuttings from the plurality of channels (50) and then transporting them to
auguring means located
9

CA 02509854 2005-06-13
above the drill bit on the drill string. The transitional zone (54) comprises
an upwardly inclined
surface (59) extending at a predetermined angle (57) of about 60 degrees from
the top of the radial
outer face (46) to the surface of the annular steel body (12). The angle may
be more or less than 60
degrees.
The annular steel body is machined from a species of steel commonly referred
to as
"C 12L 14 Grade" steel.
The bit crown is a hard metal matrix formed onto the bottom end of the annular
steel body
using a powdered metallurgy process.
Referring to Figure 4 which is the same as Figure 1, at the third annulus (34)
top rim (40) is
located a projection (64) having an inwardly oriented tip (66). The tip has
the effect of reducing
the third annulus diameter (41) between the tip (66) and the opposite side of
the rim (68) to slightly
more than diameter of the core sample so that the core sample passes between
them. This diameter
(41) is about 10.13mm and acts as a core gauge for the core that is about 10mm
in diameter in this
embodiment. The gauge also ensures that a constant diameter of core sample is
produced. The
projection (64) also applies tension to the core sample as it slides through
the third annulus causing
it to separate from the body of rock. A person skilled in the art of geology
and rock drilling will
understand that during the drilling process the core sample will stress-
relieve as it is drilled out. As
the core sample passes into the annulus of the drill crown it will be in
sliding relation with the
projection. The reverse augers have a primary function of promoting the
migration of granular
material into the junk slot channels. The also assist in grasping the core
sample as it is produced
and the combined action of the projection and reverse augers act to separate
the core from the rock

CA 02509854 2005-06-13
body close to the kerf. The length of the projection (64) can be varied to
suit the requirements of
the drilling operation. However, the shorter the length of the projection (64)
the greater the
premature wear of the drill bit and the less the capability of the drill bit
to grasp the sample. In this
embodiment of our invention, the length of the projection has been optimized.
Referring to Figures 2 and 4, each of the radially extending cutting blades
(52) has a bottom
end (70) and a top end (72). The bottom end (70) extends radially downward and
into the third
annulus (34) a predetermined distance (74) which is about 1mm. Each of the
radially extending
channels (50) has a bottom end (76) and a top end (78). The bottom end (76) of
each channel (50)
terminates at the bottom rim (38) of the third annulus (34). The diameter of
the core sample is
determined by the distance (80) (Figure 2) between the opposite top tips (70)
of the cutting blades
(52) which is about 10mm in this embodiment.
Still referring to Figure 4, within the third annulus (34) a junk slot (82) is
formed below the
projection (64) and above the tip (70) of cutting blade (52). Junk slot (82)
is about lmm wide and
9mm deep and is adapted for collecting cuttings that fall into the third
annulus. To remove the
cuttings from the third annulus, there is a plurality of radially spaced auger
blades (84) fixed to the
inside surface of the third annulus (68). Each of these radially spaced auger
blades (84) is about
2.1mm wide has an attacking surface (88), a bottom end (90) and a top end
(92). Each of the auger
blades (84) is oriented diagonally at an angle (91) across the width of the
adjacent radially
extending channel (50) and extends about 9.lmm into the annulus from the
bottom rim. The blades
are oriented opposite to the direction of rotation of the drill thereby
forming a reverse auguring
mechanism. Adjacent to each auger blade (84) is a row of evenly spaced
abrasive elements (96)
parallel to the attacking surface (88) of each auger blade. The abrasive
elements may be natural
11

CA 02509854 2005-06-13
diamonds such as the 75 SPC Kicker grade natural diamonds or synthetic
diamonds. When the dry
drill bit is rotating, the row of evenly spaced abrasive elements maintains
the inside gauge and core
sample diameter. The spaced auger blades sweep the cuttings from the third
annulus into an
adjacent channel (50) for carriage by centrifugal force away from the bit head
to the transition zone
(54). The efficiency of the reverse auger is dependent upon the angle of
attack (91) (being about
55 degrees) of the augur blades and the depth (93) of the blades into the
annulus (34). An
aggressive angle of attack improves the transfer of cuttings from the annulus
to the channels for
removal but may cause the drilling bit to stall. A low angle of attack will
cause an accumulation of
cuttings within the annulus and could also result in drill stall. As well, the
depth of the blades will
affect the design of the kerf. Our design has optimized the location, depth
and attack angle of the
reverse augur blades (84) for this embodiment.
A Second Embodiment
Referring now to Figure 5, illustrated in cross-sectional view, there is a
second embodiment
(200) of our drill bit being about 26mm long and comprising an annular steel
body (202) including
a first annulus (204), a first inside diameter (206) of about 12.4mm, a wall
(205), an inside surface
(207) a bottom end (208) and a top end (210). The top end of the annular steel
body is adapted for
coupling with a rotatable drill string (not shown) having a second annulus
with a second inside
diameter. Dimensions provided here are exemplary of one embodiment and these
dimensions may
vary according to the operational requirements of the drilling project.
The bit crown (214) of this second embodiment has a geometry that is different
than the bit
crown geometry of the first embodiment illustrated in Figure 1. The bit crown
of the second
12

CA 02509854 2005-06-13
embodiment is about 20mm wide and formed using the same hard metal matrix. It
is formed onto
the bottom end of the annular steel body using a powdered metallurgy process.
The bit crown has
a top end (216) and a bottom end (218) and comprises a third annulus (220)
having a third inside
diameter (222) of about 10.13mm, a bottom rim (224) and a top rim (226). The
third annulus (220)
extends through the bit crown (214) and is co-axial with the first (204) and
second annuli. The
third annulus (220) is adapted to receive and pass a 10mm diameter core sample
to the annular
steel body first annulus and hence to the drill string second annulus. The bit
crown further
comprises a bit head (230) or kerf having a radial profile with a radius (232)
of about 4mm for
rotatively cutting into the body of rock thereby forming the core sample and
creating cuttings.
Referring now to Figure 6, there is shown a bottom view of a second embodiment
of the
invention. Formed within the bit crown (214) is are a plurality of evenly
spaced and tapered
radially extending channels (232) adapted for carrying the cuttings away from
the bit head (230) as
more fully explained below. There is also a plurality of evenly spaced tapered
radially extending
cutting blades (234). Each one of the radially extending cutting blades (234)
is separated by one of
the channels (232). In the embodiment shown in Figure 6 there are six cutting
blades and six
channels but there may be more or fewer of blades and channels in other
embodiments.
Referring now to Figure 7, there is illustrated a side view of the drill crown
(214) of the
second embodiment of the invention. Integral to and above each of the cutting
blades (234) there is
a vertically oriented radial outer face (236) that is about 5mm high in this
embodiment. The outer
faces (236) are adapted for stabilizing the bit head against angular deviation
and gauging the bore
hole. Within each radial outer face (236) there is embedded a plurality of
vertically oriented and
parallel splines (238). Each outer face deviates at a predetermined angle
(240) from the vertical
13

CA 02509854 2005-06-13
(241). The angle is generally about 24 degrees from the vertical (241) but it
can be more or less
than 24 degrees.
A transition zone (242) is included above the bit crown and is adapted for
receiving the
cuttings from the channels (232) and transported to the drill string auger
means for removal. The
transitional zone is not integral to the bit crown of the second embodiment.
It comprises a first
horizontal surface (244) extending across the top of the face to the bottom
outside surface of the
annular steel body (202).
Refer now to Figure 8 which is identical to Figure 5. At the third annulus top
rim (226) is
located a projection (241) having a length and an inwardly oriented tip (243)
extending a
predetermined distance into the third annulus thereby reducing the third
annulus top rim (226)
diameter (227) from the tip (243) to the opposite side (245) of the rim to
slightly greater than the
diameter of the core sample (about 10.13mm in this embodiment) so that the
core sample (about
10mm in diameter in this embodiment) may pass through. The projection (243) is
in sliding
contact with the core sample, applies tension to the core sample and causes it
to separate from the
body of rock. The projection (243) also gauges the diameter of the core
sample.
Referring to Figures 5, 6 and 7, each of tapered radially extending cutting
blades (234) has
a bottom end (250) and a top end (252). The bottom end extends horizontally
across a portion of
the third annulus a predetermine distance (253). Similarly, each tapered
radially extending channel
(232) has a bottom end or inlet (254) (about 2.5mm wide in this embodiment)
and a top end or
outlet (256) (about 4.6mm wide in this embodiment). The channel bottom end
terminates at the
bottom rim (224). The diameter of the core sample is determined by the
distance (255) between
14

CA 02509854 2005-06-13
the opposite top ends (250) of the tapered radially extending cutting blades
(about 10mm in this
embodiment).
Referring back to Figure 8, a junk slot (260) (about lmm wide and 5mm deep in
this
embodiment) is formed below the projection (241) and between the projection
(241) and the
bottom end of the adjacent cutting blade (250). The junk slot adapted for
collecting cuttings within
the third aperture. The rotating dry drilling bit further includes means for
removing cuttings from
the third aperture. These means comprises a plurality of radially spaced auger
blades (262)
diagonally oriented at a predetermined angle (257) of about 55 degrees counter-
rotationally and
fixed to the inside surface (245) of the third annulus. Each of the radially
spaced auger blades has
an attacking surface (266), a bottom end (268) and a top end (270). In this
embodiment, the auger
blade is about 2mm wide and has a diagonal length of about 5.lmm. The bottom
end (268) of each
of the radially spaced auger blades terminates at the bottom rim (224) of the
third annulus. The
auger blades are diagonally oriented in the opposite direction of rotation.
The blades have an angle
of attack (257) and a depth (271) into the annulus. Generally, each blade
extends horizontally a
distance (273) of about 5mm along the inside wall of the annulus. Adjacent to
each auger blade are
abrasive elements comprising a row of either natural diamonds such as 75 SPC
Kicker grade
natural diamonds or synthetic diamonds.
In operation, as the dry drill bit is rotating, the row of evenly spaced
abrasive elements
(277) maintain the inside gauge and core sample diameter. The radially spaced
auger elements
sweep the cuttings from the third annulus into an adjacent channel for
carriage by centrifugal force
away from the bit head.

CA 02509854 2005-06-13
Referring to Figure 7, a plurality of abrasive elements (280) is embedded into
each cutting
blade surface. In one embodiment of the invention the abrasive elements
comprise natural
diamonds such as 50 SPC AAAA grade natural diamonds. These diamonds provide a
relief of
about 0.3mm above the surface of the cutting blade. In another embodiment of
the invention the
abrasive elements comprises synthetic diamonds. In yet another embodiment of
the invention the
abrasive elements comprise natural diamonds such as 50SPC AAAA grade natural
diamonds and
synthetic diamond crystals impregnated into the volume of the bit crown. The
synthetic diamonds
are thermally stable polycrystalline diamond elements plus synthetic diamond
crystals. 75SPC
Kicker grade natural diamonds or alternatively, synthetic diamonds is also
inserted into each of the
surfaces of each of the splines.
A Third embodiment
Referring now to Figure 9, there is shown in cross-section a third embodiment
of our
invention identified generally as (300). The rotating dry drilling bit of this
embodiment is about
26mm long and comprises an annular steel body (302) having a first annulus
(304), a cylindrical
wall (306) having an inner surface (308), an inside diameter (310) of about
29mm, an axis (312), a
bottom end (314) and a top end (316). The top end (316) of the annular steel
body (302) is adapted
for coupling with a co-axial rotatable drill string not shown in this diagram.
The drill string has a
second annulus with a second inside diameter equal to inside diameter (310).
There is a co-axial
bit crown shown generally as (318) is about 37mm wide and mounted to the
annular steel body
bottom end (314) over integral anchoring elements (315) and (317). As shown in
this Figure 9, the
geometry of the bit crown of the third embodiment of our invention is
different from the first and
second embodiments.
16

CA 02509854 2005-06-13
In this third embodiment, the bit crown has a top end (320) and a bottom end
(322) and
comprises a third annulus (324) having a third inside diameter (337) of about
28mm, a bottom rim
(328) and a top rim (330). The third annulus (324) extends through the bit
crown and is generally
co-axial with the first (304) and second annuli. The third annulus (324) is
further adapted to
receive and pass the core sample to the annular steel body first annulus (304)
and hence to the drill
string second annulus. The radius (311) of the bit crown is about 4mm and
determines the amount
of point loading on the bit head. The radius of bit crown in this embodiment
ensures that a high
loading is achieved on the bit head to commence the core as well as
encouraging cuttings to exit
through the channels away from the drill head. There is a bit head or kerf
(334) having a radial
profile of radius (311) for rotatively cutting into the body of rock thereby
forming the core sample
and creating cuttings.
The bit crown includes a plurality of radial outer faces (336). The radial
outer faces (336)
have a vertical profile, are about 5mm high and are adapted for stabilizing
the bit head against
angular deviation as well as gauging the annular bore hole.
Referring now to Figure 10, there is shown, in side view, the crown bit (314).
Within each
of the radial outer faces (336) there is embedded a plurality of vertically
oriented and parallel
splines (338). Each of the splines has a surface (340), a top end (342) and a
bottom end (344).
Referring now to Figure 11, there is shown a bottom view of the bit crown
(318) of this
third embodiment showing the bottom rim (328) of third annulus (324). Formed
within the within
the bit crown (328) there is a plurality of evenly spaced radially extending
channels (340) adapted
17

CA 02509854 2005-06-13
for carrying cuttings away from the bit head (324) by centrifugal force as the
drill bit rotates. As
well the bit crown (318) has a plurality of evenly spaced radially extending
cutting blades (342).
Each one of the radially extending cutting blades (342) is separated by one of
the radially
extending channels (340). In the embodiment illustrated in Figures 11 there
are 12 cutting blades
and 12 channels although there may be more or less.
Referring to Figure 10 and 11, each radially extending cutting blade (342) has
a blade
surface area generally indicated at (346). Each blade has a slightly
diminishing tapered width from
the bottom end (348) of the blade to the top end (350) of the blade. The
amount of the blade taper
is much less than the previous two embodiments and may be as small as a few
millimeters between
the top and bottom of the blade. As well, each radially extending channel
(340) has a channel
surface area generally shown as (356) and an increasing tapered width of about
2.5mm from the
top end or inlet (358) of the channel to about 3.8mm at the bottom end (360)
or outlet of the
channel. The amount of the taper from bottom to top end of the channel may be
as small as 1.3mm.
In this embodiment, the surface area (346) of each blade (342) is slightly
less than the surface area
(356) of each channel (328) but this is not always the case.
As shown in Figure 10, each radially extending cutting blade (342) and each
radially
extending channel (328) has a diagonal orientation at an angle (351) of about
35 degrees
conforming to the direction of rotation (370) of the rotating dry drill bit.
This angle may be more
or less than 35 degrees. This diagonal configuration promotes the augering
action of the drill bit to
remove cuttings away from the drill head.
Referring now to Figures 10 and 11, each blade surface (346) is raised above
each channel
surface (356) a distance (371) of about lmm thereby creating blade surface
opposite side walls
18

CA 02509854 2005-06-13
comprising a blade surface leading side wall (372) and a blade surface lagging
side wall (374).
The blade surface leading side wall (372) and the blade surface lagging side
wall (374) are angled
at a predetermined angle (376) of about 35 degrees towards the direction of
rotation of the dry
drilling bit (370) as shown in Figure 10 Section, A-A. This angle may be more
or less than 35
degrees. A plurality of abrasive elements (380) is embedded into the blade
surface. In one
embodiment of the invention the abrasive elements comprise natural diamonds
such as 50 SPC
AAAA grade natural diamonds plus synthetic diamond crystals impregnated into
the volume of the
bit crown. In another embodiment of the invention the abrasive elements
comprises synthetic
diamonds comprising thermally stable polycrystalline diamond elements plus
synthetic diamond
crystals impregnated into the volume of the bit crown. A row comprising a
combination abrasive
elements (382) 75 SPC Kicker grade natural diamonds and (384) 75 AAAA grade
natural
diamonds or, alternatively, synthetic diamonds is also inserted into each of
the radial surface of
each of the splines.
Referring to Figure 12, there is a transition zone (390) that is adapted for
receiving the
cuttings from the plurality of channels and then transporting them to an
auguring means located
above the drill bit on the drill string. The transition zone (390) is located
above the bit crown (318)
and comprises a horizontal surface (392) extending to the surface of the
annular steel body (302).
The transitional zone receives cuttings from the channels and transfers them
to an auguring means
located above the transitional zone for transport out of the bore hole.
Referring to Figures 11 and 12, each of the radially extending cutting blades
(342) bottom
ends (348) extend horizontally into the third annulus (324) a predetermine
distance (323) of about
19

CA 02509854 2005-06-13
lmm. The diameter of the core sample is determined by the distance (375)
between the opposite
top ends (348) of the cutting blades (342) which is about 28mm.
Within the third annulus (324) a junk slot (392) is formed within the inside
surface of the
third annulus below the tip (348) of cutting blade (342). Junk slot (392) is
about lmm wide and
4.5mm deep and is adapted for collecting cuttings that collect within the
third annulus. To remove
the cuttings from the third annulus, there is a plurality of radially spaced
auger blades (394) having
a reverse diagonal orientation at an angle (395) and fixed to the inside
surface of the third annulus
(324). The blades are about 2mm wide and have a diagonal length of about
4.8mm. In this
embodiment there are 12 such augur blades. Each of these radially spaced auger
blades (394) has
an attacking surface (396), a bottom end (398) and a top end (399). Each of
the bottom ends (398)
of the radially spaced auger blades (394) is generally situated midway across
an adjacent channel
(340) and extends a depth (393) from bottom rim (328) into the third annulus.
These blades form a
reverse auguring mechanism. Adjacent to each auger blade (394) attacking
surface (396) is a
plurality of abrasive elements (391) generally comprising either 75 SPC Kicker
grade natural
diamonds or synthetic diamonds. When the dry drill bit is rotating, the
abrasive elements maintain
the inside gauge and the core diameter. The spaced auger blades sweep the
cuttings from the third
annulus into an adjacent channel for carriage by centrifugal force away from
the bit head. In this
third embodiment the angle of attack (395) is 55 degrees from the vertical.
The angle may be more
or less than 55 degrees. The depth (393) of the augur blades in this third
embodiment is about
4.8nun and does not extend through the third annulus.
Embedded into the surface of each cutting blade (342) is a plurality of
abrasive elements
generally comprising natural 50 SPC AAAA grade diamonds plus synthetic diamond
crystals

CA 02509854 2005-06-13
impregnated into the volume of the bit crown. In another embodiment the
diamonds can be
synthetic diamonds comprising thermally stable polycrystalline diamond
elements plus diamond
crystals impregnated into the volume of the bit crown. Embedded into the
surface of the vertical
splines (338) is a combination of diamonds comprising of 75 SPC AAAA grade
natural diamonds
and 75 SPC Kicker grade natural diamonds or synthetic diamonds.
A Fourth Embodiment
Referring to Figures 13, 14 and 15 there is shown a fourth embodiment of our
invention. In
this embodiment the drill bit (400) is about 27mm long. The dry drill bit
comprises an annular
steel body (402) having a first annulus (404), a wall (403), a first inside
diameter (406) of about
12.4mm, an inside surface (403), a bottom end (408) and a top end (410). The
top end (410)
adapted for coupling with a rotatable drill string having a second annulus
with a second inside
diameter. There is a bit crown (412) about 20mm wide comprising a hard metal
matrix formed
onto the bottom end of the annular steel body on anchoring elements (409) and
(411) using a
powdered metallurgy process. The bit crown (412) has a top end (414) and a
bottom end (416) and
comprises a third annulus (418) having a third inside diameter (420) of about
10mm and a top rim
(424). The third annulus extends through the bit crown and is co-axial with
the first (404) and
second annuli and adapted to receive and pass the core sample to the annular
steel body first
annulus and hence to the drill string second annulus. There is also included a
bit head (426)
comprising a plurality of thermally stable polycrystalline diamond cutting
elements (428) for
rotatively cutting into the body of rock thereby forming the core sample and
creating cuttings.
Each of the cutting elements (428) has a cylindrical shape having a diameter
of about 6mm and a
thickness of about 1.5mm and comprising a flat attacking face (430) and a
convex lagging face
21

CA 02509854 2005-06-13
(432). The attacking face has a cutting edge (434) which will engage the body
of rock about its
entire circumference. The cutting elements are oriented at a rake angle (429)
of about 20 degrees
so that each attacking face (430) cutting edge (434) is angled to attack the
body of rock. The
cutting elements are oriented at 90 degrees to each other around the
circumference of the bit.
Between each of the cutting elements there is an opening (440) adapted to
remove cuttings
away from the bit head. The opening is oriented at a diagonal of about 35
degrees from the vertical
axis. The bit crown further includes a plurality of radial outer faces (442).
Each of the radial outer
faces (442) is integral to the bit crown and located above each of the cutting
elements (428). The
outer faces are adapted for stabilizing the bit head against angular deviation
and gauging said bore
hole. Each of the outer faces has embedded within it a plurality of 50 SPC
Kicker grade natural
diamonds. Also embedded within each outer face is a 1.5mm by 1.5mm thermally
stable
polycrystalline diamond cutting element (447). The drill bit also includes a
transition zone (444)
adapted for receiving the cuttings from the openings for transport away from
the bit crown.
At the third annulus top rim (424) is located a projection (450) having a
length and an
inwardly oriented tip (452) extending a predetermined distance into the third
annulus thereby
reducing the third annulus diameter to 10.13mm from the tip (452) to the
opposite side (454) of the
rim which is slightly wider than the diameter of the core sample. The
projection is in sliding
contact with the core sample, applies tension to the core sample thereby
causing it to separate from
the body of rock and gauges the core sample.
To remove the cuttings from the third annulus, there is a plurality of
radially spaced auger
blades (460) having a reverse diagonal orientation at an angle (462) of about
55 degrees (464) and
22

CA 02509854 2005-06-13
fixed to the inside surface of the third annulus. The blades are about 2mm
wide and have a
diagonal length of about 2mm. In this embodiment there are 4 such auger
blades. Each of these
radially spaced auger blades has an attacking surface (464), a bottom end
(466) and a top end
(468). Each auger blade extends a depth (470) of about 2mm into the third
annulus. These blades
form a reverse auguring mechanism. Adjacent to each auger blade attacking
surface is a plurality
of abrasive elements (472) generally comprising either 50 SPC Kicker grade
natural diamonds or
synthetic diamonds. When the dry drill bit is rotating, the abrasive elements
maintain the inside
gauge and the diameter of the core. The spaced auger blades sweep the cuttings
from the third
annulus into an adjacent channel for carriage by centrifugal force away from
the bit head.
It is apparent from the foregoing description that the present invention and
its preferred
embodiments are improvements over the known art and meet the objectives set
forth herein.
Although this description contains much specificity, these should not be
construed as
limiting the scope of the invention by merely providing illustrations of some
of the embodiments of
the invention. Thus the scope of the invention should be determined by the
appended claims and
their legal equivalents rather than by the examples given.
23

Representative Drawing