Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
This invention relates to a vibratory, core drill appara-
tus.
Core samplings of unconsolidated material, such as
gravel or soil, cannot always be successfully accomplished with standard
rotary core dri~ls. Such sàmplings of unconsolidated material are com-
monly done, for example, during prospectin~ of placer gold deposits. In
10 this case, the heavier gold is usually found at the bottom of uncon-
solidated material resting on top of bedrock. For this reason, the pros-
pector would normally want to sample only the material in the two feet
immediately above the bedrock.
Yibratory core sampling apparatuses have been suggested
in the past as seen, for example9 in United States Patents 3,301,336 and
3,352,160, both to Mount. However, neither OI these patents gives
structural details of the vibrator, nor discusses the nature of the vibra-
tion.
2~
In some earlier core drills which may be referred to as
vibratory drills, the actual downward movement of the drill is accom-
plished by percussion. In other words, the drill bit hammers through the
material being sampled. The percussion can result in the loosening of the
25 threaded connectios on the core barrel and, moreover, may result in
failure of the drill steei through crystalization of the metal.
Another problem associated with obtaining core samples
of unconsolidated material is retaining the desired sample within the core
30 barrel as it is withdrawn. Loose material, such as gravel, silt or organic
material, tends to drop out of the bottom of the core barrel. Accordingly,
core drilling apparatuses such as those in United States Patent 3,301,336
to Mount and United States Patent 3,833,075 to Bachman employ flexible
fingers to retain the sample. The fingers are bent out of the path of the
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core sample as it enters the barrel, but resist movement of the sample in
the opposite direction when the barrel is moved upwardlyO These ~lexible
fingers are not always sufficient to retain the core sample, particularly if
it is composed of wet silt or the like.
S
It i5 desirable in many cases, such as placer gold pros-
pecting, to retrieve a sample at a certain depth, while discarding material
above the sample. One approach to accomplishing this is found in United
States Patent 4,130,170 to Holman which discloses a probe for use in
10 geological surveys. The probe has a side outlet located a distance above
the bottom so that material is retained only between the outlet and the
bottom. HoweYer, the outlet is located only a few inches above the
bottom which means that only a small length of core sample can be taken.
The probe has no means for varying the length of core sample taken.
Other core sampling devices are disclosed in United
States Patents 3,023,820 to Desvaux; 3,0~9,185 to Herbold; 3,805,898 to
Whitney and 3,5159230 to Tomaine.
SUMMARY OF THE INYENTION
According to the mvention, a vibratory, core drill ap-
25 paratus comprises a housing and an eccentric member rotat~bly mountedin the housing for vibrating the apparatus when the eccentric member is
rotated about an axis of rotation. There is means for connecting a rotary
power source to the eccentric member to rotate the eccentric member.
There is also means for connecting to the housing a core drill stem with a
30 longitudinal axis so the longitudinal axis is perpendicular to the axis of
rotation of the eccentric member.
The apparatus may also include a side ejector core
sampler having a top end with a threaded fitting for connecting the sam-
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pler to the housing or a core drill barrel, a bottom end with a threadedfittingfor connecting the sampler to a drill bit or to a core drill barrel, a
side openin~ between the top end and the bottom end, and an internal
passageway communicating outwardly through the bottom end and the side
5 opening.
The apparatus may further comprise a core retaining bit
having a top end with means for connecting the bit to the bottom end of
the sampler or below a drill barrel connected to the bottom end of the
10 sampler, a bottom end, a longitudinal passageway extending between the
top end and the bottom end, and an open-ended flexible tube positioned
within the passageway. Material moves upwardly relative to the drill bit
during drilling and passes through the tube. The tube collapses to retain
material when drilling stops.
Preferably, the bit further comprises a plurality of
flexible fingers having bottom ends connected to the inner wall and con-
verging upwardly in a generally conical shape. Each of the fingers has a
top end which touches the top ends of other said fingers.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure 1 is a side elevational view of a vibratory, core drill ap-
pratus) according to an embodiment of the invention, and
a perspective view of a motor connected to the appara-
tus by a flexible power shaft,
Figure 2 is an enlarged perspective view of the top portion of the
apparatus of Figure l,
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Figure 3 is an exploded perspective vièw of the components shown
in Figure 3,
Figure 4 is a perspective view of a side ejector core sampler from
the apparatus of Figure 1,
Figure 5 is a longitudinal sectional view of the sampler of Figure
4, and
~igure 6 is a perspective view of a core retaining bit from the
apparatus of Figure 1 with the side wall broken away.
15 DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referrin~ to the drawings, and in particular Figure 1, a
vibratory, core drill apparatus 1 includes a housing 2 connected to the top
end 4 of a core sampler 6. The core sampler has a bottom 8 connected to
a core retaining b.t l0. The housing 2 has an internal eccentric member,
described below, which is connected to a motor 12 by a flexible power
shaft 14.
.
The housing 2 and its internal eccentric member are
shown in better detail in Figures 2 and 3. Housing 2 is T-shaped, having a
cylindrical portion 16 which is horizontal in use. Horizontal portion 16 has
a cylindrical hollow interior 18 shown in Figure 3.
An eccentric member 20, shown in Figure 3, is rotatably
mounted in cylindrical interior 18 of housing 2. Eccentric member 20 is an
elongate member fitted with a pair of spaced-apart roller bearings 22 and
24. There is a stub shaft 26 at one end oi eccentric member 20 which
projects from the housing 2 as seen in Figure 2.
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The eccentric member 20 is sealingly received within the
hollow interior so that the ho~low interior can hold an oil bath for the
eccentric member. The oil bath s~erves both to dissipate heat and to
lubricate the bearings. At the end of housing 14 opposite stub shaft 26,
5 the housing is sealed by a threaded plug 28 threadedly received within the
interior of the housing. At the opposite end of the housing, a fitting 30 is
threadedly fitted within the interior of the housing. Fitting 30 has a
central aperture 32 through which stub shaft 26 projects. An oil seal 34
on the fitting prevents oil from lealcing through aperture 32 over the stub
10 shaft. Fitting 30 has a male threaded portion 36 which receives a female
threaded fitting 38 of flexible power shaft 14 as shown in Figure L The
flexible power shaft is of the type having a stationary motor casing with a
flexible, rotatable core. This core has an end which is square in section
and fits within a similar-sized square section aperture in the end of stub
15 shaft 26. The stub shaft and fitting 30 accordingly provide means for
connecting the rotating power source to the eccentric member 30.
Eccentric member 20 is generally T-shaped between
bearings 22 and 24. Two portions 40 and 42 are machined out of the
20 eccentric member, leaving a flange 44. The center of gravity of the
eccentric member is thereby eccentric relative to its axis of rotation 46
shown in Pigure 2. This axis is horizontal when the apparatus 1 is in use.
~Iousing 2 has a portion 48 which is vertical when the
25 apparatus is in use. Vertic~l portion 48 is a hollow cylinder with a male
threaded end 50 which provides means for connecting the housing to a
core dri~l barreL
In the case of apparatus 1, core drill barrel 52, shown in
30 Figures 1, 4 and 5, forms the casing for the side ejector core sampler 6.
The female threaded top end 4 connects the sampler to the housing or to
another length of core drill barrel which is connected to the housing. The
bottom end ~ has a male thread for colmecting the sampler to the drill bit
10 RS shown in Figure 1 or to another length of core drill barrel. The
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sampler 6 has a side opening 54 between the top end and the bottom end
and generally near the top end. An internal passageway 56 communicates
outwardly through the bottom end 8 and the side opening 54. The
passageway 56 is coaxial with the longitudinal axis 58 of the core drill
5 barrel 52 and curves outwardly to the side opening 54. As seen best in
Figure 4, the side opening is generally elliptical in shape. Longitudinal
axis 58 is perpendicular to the axis of rotation 46 of the eccentric member
when the sampler is connected to the housing as shown in Figure 1.
Referring to Figure 1, core retaining bit 10 is connected
to the bottom end 8 of the core sampler 6. The core retaining bit is shown
in better detail in Figure 6. Bit 10 has a female threaded top end 60
providing means for connecting the bit to the bottom end 8 of core drill
barrel 52 of sampler 6 or a standard core drill barrel. Bit 10 is in the
15 shape of an open-ended tube with a bottom portion 62 which tapers
towards an annular cutting edge 64 at the bottom end of the bito The bit
has a longitudinal passageway S6 extending between the threaded top end
60 and the bottom cutting edge 64. Passageway 66 is defined by the
generally cylindric~l inner wall 68.
An open-ended flexible tube 70 is positioned within the
passageway 66 of the bit. The tube of the preferred embodiment is of
sheet-like plastic, although other flexible rnaterials eould be used such as
rubber or canvas. The flexible tube has a bottom end 72 held against the
~5 inner wall of the bit by a pair of retaining rings 74 and 76. The bottom
end of the tube is wrapped over the bottom ring 76, while the top ring 74
is placed over the tube. The rings 74 and 76 are held tightly against the
tflpered bottom portion 62 of the bit by the threaded bottom end of the
sampler 6. While the bottom end of the tube is held against the inner wall
30 of the bit, the top end 78 is open and free. As seen in ~igure 6 for the
preferred embodiment, the tube extends beyond the top end 60 of the bit.
Material moving upwardly relative to the bit during the drilling process
passes through the tube and keeps the tube open. However, when drilling
stops, the tube co31apses if the material starts to move downwardly
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towards the cutting edge 64 and consequently retains material within the
bit and core drill barrel 52.
The core retaining bit 10 also includes a plurality of
5 flexible fingers 80 ~or retaining samplles within the core when the barrel is
withdrawn. These fingers 80 comprise leaf springs, each having a bottom
end 82 held against the inner wall 68 of the bit by the retaining ring 76. A
rivet 84 connects each of the leaf springs to the ring 76. As seen, the
flexible ingers converge upwardly from ring 76 in a generally conical
10 shape. Each flexible finger therefore has a top end 86 which touehes the
top ends of adjacent fingers. During downwards movement of the bit 10
and the core drill barrel 52, material moving upwardly relative to the bit
pushes apart the flexible fingers and moves upwardly through flexible tube
70 and the barrel. However, when drilling stops, the flexible fingers close
15 together in the conical shape shown in ~igure 6 to prevent material from
passing downwardly through the bit.
In operation, apparatus 1 is assembled and oriented as
shown in Figure 1. When samples are being taken from relatively shallow
20 depths, the apparatus may be used as is with housing 2 grasped by the
driller's hands. However, when drilling to greater depthsJ the apparatus
can be attached to a standard drilling rig for ease of operation and to
maintain propeP alignment. The rotatable eccentric member 20 within
housing 2 is connected to the motor 12 by the fle2{ible power shaft 14 as
25 described above. Motor 12 may be any suitable gasoline or diesel powered
motor. The rotational speed of the eccentric member is governed by that
of the motor. For drilling above the water table in hard pan, glacial till or
hard clay, a rotQtional speed of over 12,000 r.p.m. for eccentric member is
preferable. This results in over 12,000 vibrations per minute at the bit 10.
30 A typical small motor operates at 3,600 r.p.m., for example, so pulleys
and V-belts m~y be used to increase the speed of member 20 by a factor
of 4 to 14,400 r.p.m. With such an arragement, gravel, sand or clay below
the water table would be drilled with the motor at half throttle, while
one~uarter throttle would be suitable for organic sediments, silt or
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quicksand to give the samples time to enter the tube. Otherwise the drill
could drop too fast. It has been found that a clockwise directional
rotation of the eccentric member by fle~ible shaft 14, indic~ted by arrow
88 in Figure 1, is preferable since this keeps the various threaded
5 connections tight instead of the vibrfltions loosening them.
Sampler 6 can be connected directly to the housing as
shown, or additional lengths of core barrel can be fitted between the
sampler and housing if the distance between the surface and the sampling
depth is greater than the length of sampler 6. Similarly, core retaining bit
10 can be connected directly to the bottom of the sampler to retrieve a
sample as deep as the combined length of passageway 56 in sampler 6 and
passageway 66 in core retaining bit 10. If a longer sampler is wanted, one
or more additional lengths of core barrel are fitted between the sampler 6
15 and the core retaining bit 10. The driller can therefore retrieve any
desired length of sample at any desired drilling depth. For example, if the
bedrock is located 13 feet below the surface, the driller may wish to take
a 3 foot sample on top of the bedrock. Ten feet of core barrel is screwed
onto male threaded end 50 of housing 2 and then sampler 6 is screwed onto
20 the bottom of the 10 foot length o~ core barrel. Assuming that the
combined lengths of passageway 56 in sampler 6 and passageway 66 in
core retaining bit 10 is approximately 2 feet, an additional 1 foot length of
core barrel is fitted between the sampler and the bit. With motor 12
operating, the appflratus is held with cutting edge 64 of the bit against the
25 surface. Vibrations move the bit downwardly towards the bedrock. As the
bit moves downwardly, material moves upwardly through passageway 66 in
the bit, bending 1exible fingers 80 outwardly. The material moves
upwardly through flexible tube 70 and passageway 56 of core drill barrel
52 until it eventually reaches side opening 54. Material is expelled
30 through side opening 54 until the cutting edge 64 reaches bedrock. At this
point, the required sample of material is located between the side opening
and the bottom of the bit. The apparatus is then pulled upwardly. The
loose material may tend to move out through the bottom of the bit, but
the upward pressure of moving material is removed from flexible fingers
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80, so they return to the position shown in Figure 6 to resist an outflow of
material. At the same time, flexible tube 70 collapses, providing
additional means for keeping the sample within the core drill barrel 52.
Since the drilling is accomplished by vibration instead of
rotation or percussion, no cooling or lubricating water is required and
uncontaminated core samples are r~etrieved from unconsolidated forma-
tions. Penetration speeds of up to 2 seconds per ~oot are achieved.
While gasoline or diesel power is suggested above, it may
be appreciated that electric, hydraulic or pneumatic power could also be
used.
