Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
This invention has utility in the excavating field and,
most particularly, in the mining of coal formations.
More specifically, it is believed the invention will be
especially useful when the method is used in conjunction with
the type of cutter bits currently in use in the coal mining
field and with the new type bit disclosed herein, and it is
believed it will be a useful advance in the design of the
machines used to reduce coal formations and, also, will be a
useful advance in the methods used to reduce coal formations.
New methods and new machines are contemplated by the
present invention.
By way of example, it is believed the invention can be
used where point attack type cutter bits are now used in coal
mining, especially when such point attack type cutter bits are
being power driven through the formation being reduced, such as
in coal mines.
Various types of machines have been and are known in the
art for digging and reducing earth formations and, also, for the
mining of minerals, such as coal and other deposits.
Machines predominantly used in the earth boring art are
generally exemplified by those in use for oil well drilling and
which generally comprise multiple cone type rollers, where
conically shaped roller cones have blunt or dome shaped carbide
compacts imbedded in their outer peripheryO
The conically shaped roller cutters are mounted on
convergent shafts on a frame on the lower end of the drill string
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and rotation of the drill string cuases the rolling cutters to
rotate and the compacts to hammer the bottom of the hole and
fracture the material. Such machines are more fully described
and best exemplified by United States Patent Nos. 2,774,570 and
2,687,875.
Also, in the earth boring field, there are other machines
known as tunnel boring machines or raise boring machines which
utilize cylindrical rolling cutters which also have blunt carbide
compacts imbedded in the cutters' outer periphery. These tunnel
boring machines have cutters that are mounted upon a frame
located on the lower end of a drill string, and rotation of the
drill string while holding the cutters against the formation to
be reduced will cause the cutters to rotate and the carbide
compacts will impact and fracture the earth formation These
machines are more fully described, and may be exemplified by,
United States Patent NosO 3,797,592; 3,734,213 and 3,679,009.
The machines presently in use for reducing coal formations
generally are comprised of power driven rotary drums having
cutter bits fixedly mounted on the periphery of each drum. In
order to reduce and fracture the coal formation, the drum, and
with it the cutter bits, are rotated under power and driven
through the formation of coal, thereby fracturing the coal
formation by both impact of the bit and friction of the bit as it
is driven on through the formation.
Once the drum has been power driven through the formation,
the coal falls to the floor of the mine under the machine and is,
usually, scooped into a conveyor which will then remove the coal
from the area.
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In general, it has been found that the cutter bits used on
such a drum are, preferably, the individually rotatable pick
type bits which are comprised of a hard wear resistant point at
the foremost end of the bit, such as a carbide point that
initially impacts and fractures the coal seam. These point
attack type cutter bits are used extensively in the mining and
earth digging art and find particular application to the mining
of coal formations. Such cutter bits are described in greater
detail and best exemplified by United States Patent Nos.
3,841,708; 3,830,546; 3,605,565; 3,519,309 and 3,499,685.
The desirable feature of these types of cutter bits is that
they are held rotatably in a support block with the support block
usually being mounted upon a power driven rotary drum or disc.
When the bits rotate freely about their longitudinal axis in
the holder, a self-sharpening effect occurs on the bit when
engaged with the earth formations, and especially when used on
coal formations.
The above-mentioned cutter bits are usually mounted so that
the tips of the bits fracture the coal seam because of the
initial impact and penetration of the carbide point and also
continue to cut with a scraping action. There are, however,
some drawbacks when using the cutter bits in that the cutting
edges of the hardened tips are extremely brittle with the result
that the tips frequently break off, particularly when the cutter
is reversed or when encountering hard inclusions in a coal seam.
Further, when mining coal with currently known methods,
the friction of dragging the bits through the slightly fractured
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or the unfractured formation increases the horsepower require-
ments of the machine and wears away the parent material of the
steel bit surrounding and holding the carbide pointO Further,
the friction created by forcing the bits through the unfractured
formations creates a severe amount of dust in the working area
which creates unhealthy and hazardous working conditions within
the coal mine.
With the presently known machines used in coal mining,
and with the cutter bits presently known, there is a further
danger that sparks created by the steel bits engaging in the coal
seam could possibly cause an explosion of any mixture of dust
and/or methane gas that may be in existence in the working area.
It is an object of the present invention to present a new
and more efficient method of reducing earth formations,
especially coal formations.
It is an object of the present invention to present new
and improved machines for reducing earth formations, especially
coal formations.
It is an object of the present invention to possibly reduce
the horsepower requirements per ton of coal necessarily expended
from an excavating machine, and especially from a coal mining
machine.
It is a further object of the present invention to provide
an apparatus and method of mining mineral formations, and
especially coal formations, wherein the frictional engagement of
the cutter type bits used to fracture the formations is reduced.
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It is a still further object of the present invention to
provide a method and apparatus for mining mineral formations,
and especially coal formations, to reduce the sparking that may
occur when the cutter bits are driven through the formation to
be reduced.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to new method and improved
apparatus for excavating earth material, especially coal
formations. It is believed that the invention will be specifically
applicable to the mining of coal formations when using bits
already used in the industry, and especially when using cutter
bits known in the art as the pick type cutter bits and when
using the new type cutter bit disclosed hereinO
According to the present invention, a new method of mining
mineral formations, such as coal, is contemplated which comprises
the steps of driving the rotatable structural member in one
direction of rotation about its longitudinal axis, engaging the
coal formation with freely rotatable cutter support assemblies
mounted on said structural member and feeding the power driven
drum assembly toward the formation so that the engagement with
the coal formation will impact the cutter bits into the coal and
then drive the cutter support assemblies in a reverse direction
than that of the structural member, allowing the cutter bits that
have impacted to rotate away from the coal formation.
It is contemplated that this way of reducing a coal forma-
tion will minimize the dust and sparks that normally occur in
mining, especially in mining coal formations.
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Further according to the present invention, an improved
excavating machine is contemplated, especially for mining coal
formations, and comprises a movable support frame having a power
drive mechanism mounted thereon. A rotatable structural member,
which may be a large drum, is mounted on said movable frame and
adapted to be driven in rotation by the power drive mechanism
also mounted on the movable frame. A rotatable cutter support
assembly is mounted on said structural member so that it is
freely rotatable around its longitudinal axis and will be able
to rotate in a direction in relation to the rotatable structural
member.
Cutter bits, for example, the individually rotatable pick
type bits, are mounted on the longitudinal periphery of the drum
assembly for engagement with a coal formation.
A nonrotatable type cutter bit may also be used with the
new apparatus. It is believed that the best nonrotatable type
bit would be one comprising a wide, relatively flat forward
working portion that is thin in cross section and whose foremost
face is preferably curved rearwardly when viewed in side and
all faces of the forward working portion diverse as they extend
rearwardly of the forward working portion.
When the movable frame is positioned so that the cutter
bits will engage the coal, the rotatable structure is driven in
one direction of rotation about its longitudinal axis. This
action causes the cutter bits, either the freely rotatable point
attack type bits, or the sharp edged nonrotatable type bits,
to impact and penetrate the coal formation with their forward
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working portions; however, the resistive force from the coal
formation then causes the cutter support assembly to rotate
about its longitudinal axis in the reverse direction from that
of the power driven rotatable structural member.
The movable frame may be moved so as to apply pressure for
impact force and also to move the drum assembly back and forth
over the face of the coal seam or mineral deposit to be reduced.
The present invention also contemplates a method of making
a head assembly to go on machines for reducing coal formations
and which comprises the steps of fabricating a structural member
so as to be mounted on a movable frame and driven in rotation
about its longitudinal axis, mounting a cutter support assembly
with cutter bits mounted thereon on said structural member so
that it has free rotation about its longitudinal axis in relation
to the structural member, and when the structural member is
driven in rotation about one direction around its longitudinal
axis, the cutter support assembly is allowed to rotate in a
reverse direction about its own longitudinal axis in relation to
the structural member.
The present invention also contemplates a new cutter head
for a mining machine which comprises a structural member adapted
to be driven in rotation about its longitudinal axis and a
cutter support assembly mounted on the structural member and has
cutter bits mounted on the longitudinal periphery of the drum
assembly for engagement with mineral and other formations, such
as coal and the like.
The present invention also contemplates a new cutter support
assembly for coal mining which comprises a cutter support member
having an internal bore and bearing means in said internal bore
adapted to allow free rotation of a cutter support member on a
bearing surface and cutter bits mounted on said cutter support
member.
The present invention also contemplates the method of making
a cutter support assembly for a cutter head for a coal mining
machine and comprises the steps of fabricating a cutter support
member and providing the cutter support member with an internal
bore and providing the internal bore with bearing means to allow
free rotation of a cutter support member upon a bearing surface.
It is believed that the above invention will be especially
useful in reducing coal formations, and should eliminate much
of the frictional contact now occurring when reducing coal
formations. The dust and sparks which can be generated in
mining coal should be minimized.
Along with the above benefits, it is believed that the
horsepower requirement of the mining machines could be decreased
per ton of coal mined. The mining of coal presently consists of
impacting the coal seam with the tip of a cutter bit, thereby
fracturing the coal formation, and then driving the bit on
through the formation in the same direction. The bit is mounted
on a drum assembly and encounters further frictional engagement
with the coal as it is being driven on the drum. This invention
is based on the concept that the driving of the cutter bits
through the formation may not be necessaryO It is believed the
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provision of a freely rotatable cutter support assembly that
rotates in a direction opposite from that of the power driven
structural member will accomplish the necessary impact on a
coal seam in order to fracture it.
The exact nature of the present invention will become
more clearly apparent upon reference to the following detailed
specification taken in connection with the accompanying drawings
in which:
Figure 1 is a side view of an improved machine performing
the method according to the present invention.
Figure 2 is a top view of an improved machine according to
the present invention.
Figure 3 is another embodiment of an improved machine
according to the present invention.
Figure 4 is a view IV-IV on Figure 2.
Figure 5 is a sectional view of a cutter support assembly
according to the present invention.
Figure 6 is a side view of a nonrotatable bit according
to the present invention.
Figure 7 is a front view of the nonrotatable bit shown
in Figure 6.
Figures 8 and 9 indicate a type of lacing pattern that
can be used with the present invention.
Figures 10 and 11 are modifications of a cutter support
assembly according to the present invention.
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DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings somewhat more in detail, dis-
closed in Figure 1 is a mineral formation shown at 10 that is
to be mined or otherwise reduced. Preferably, the mineral for-
mation 10 is a coal formation. Engaging the coal formation 10
is an apparatus having a movable frame 12 and a rotatable
structural element 14. Rotatable structural member 14 is
rotatably mounted on movable frame means 12 and a power drive
means 13 drives structural element 14 in rotation in a clockwise
direction as shown by the arrow.
The rotatable structural element may be a drum or other
similar piece of equipment used on most machines, and around
the outer periphery of the drum, or equidistant from a center
line of the structural elements, are located support posts 16
which are welded and solidly connected to structural member 14.
Support posts 16 are used to mount the rotatable cutter support
assemblies 18.
Cutter support members 18 are freely rotatable through 360
degrees about their axial center line and may be supported by
having a support post 16 at each axial end of cutter support
member 18. Mounted on the outer periphery of the cutter support
member 18 are cutter bits 20 that actually engage the coal for-
mation 10 in order to reduce it.
The cutter bits 20 are releasably held on the periphery of
the support members 18 such that the longitudinal axis of a
cutter bit is inclined toward a first direction of rotation
about the axis of the support member 18.
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Upon engagement of cutter bits 20, with the coal formation
10, the cutter support member 18 actually rotates in a second
direction opposite to that of the power driven rotatable
structural element 14 and opposite to the aforementioned first
direction of rotation. Cutter bits 20 could take almost any
form; however, the embodiments shown in Figures 4 and 6 are
thought to be the preferable type of cutter elements to be used
with the present invention.
Shown in Figure 2 is a top view of what is shown in Figure 1
with a movable frame means 12 driving the structural element 14
in rotation. Mounted at various places over the outer periphery
of the rotatable structural element 14 are support posts 16 and
these are shown supporting the rotatable cutter support members 18.
The rotatable cutter support members 18 should be distributed
around the periphery so that the cutter bits 20 form any of the
known and desired lacing patterns so as to reduce the coal forma-
tion. Again, the rotatable cutter support members 18 should be
located so that they are freely rotatable and equidistant from a
common axis.
Referring now to Figure 3, what is shown therein is a modi-
fied drum of a common mining machine. In the present application,
movable frame means is not shown; however, a power drive means 13
is shown attached around the center of the boom or rotatable
structural member 14.
Substantially spiralling rib 22 is usually found on the boom
or drum 14 and this spiralling rib has been modified by placing
support posts 16 at various locations on the spiralling rib 22.
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On each side of the support posts 16, rotatable cutter support
assemblies 18 are mounted and are freely rotatable around shaft
24, which is shown connecting them through support posts 16.
Shaft 24 will fit through support posts 16 and may have a
sleeve for a bearing so that both cutter support assemblies 18
may freely rotate in unison with one another on support posts 16.
Cutter bits are, of course, mounted on cutter support members 18,
and when the rotatable structural member 14 is driven in rotation,
while the cutter bits are engaging the coal formation, the cutter
support members 18 will rotate in a direction opposite to that of
structural member 14.
Shown in Figure 4 is a typical tool holder 26 having a pick
type bit 28. The shank 30 of the bit 28 can be inserted into the
bore 32 of support block 26 and releasably held in the block.
The block assembly may be fastened on a rotatable cutter support
member 18 in any desired pattern.
Referring now to Figure 5, what is shown therein is a shaft
24 which is extending through a rotatable support member 18,
shaft 24 having on either end support posts 16. In Figure 5,
bearing 34 is shown mounted between rotatable support member 18
and supporting shaft 24. As mentioned earlier, all that is
needed is a bearing means to support the shaft rotatably in
support member 16, bearing means being either an anti-friction
bearing or, perhaps, a sleeve member mounted between support
posts 16 and around shaft 24.
Shown in Figures 6 and 7 is a new bit 36 contemplated by the
present invention which has a generally flat forward working por-
tion 38 which is comprised of a hard wear resistant material.
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The forward working portion 38 has an arcuate, sharp forward
edge 40 used for engaging and fracturing the coal. Two faces 42
and 44 diverge rearwardly from the arcuate portion as the faces
42 and 44 extend rearwardly from the edge.
The cutter bit 36 has a rearward shank portion 46 which is
releasably inserted in a tool holder which may be mounted upon a
rotatable cutter support assembly. The bit 46 has an abutment
shoulder 48 formed at the juncture of the shank 46 with the for-
ward working portion 38. The abutment shoulder 48 will preferably
abut the forward face of the support block.
Shown in Figures 8 and 9 is a typical lacing pattern that may
be found on a drum according to the present invention. Some sort
of lacing pattern must be formed so that each and every section
of the coal on the face will be fractured by a pick on the
rotatable cutter support assembly.
In Figure 8, shown on a rotatable cutter support assembly is
a typical pick type bit 28 with holder 26 supporting the bit 28.
It is possible, by either staggering the bits on the cutter support
assembly or staggering the cutter support assembly, that a lacing
pattern as is shown in Figure 9 will be formed across the coal
face so that all the faces of the coal are impacted at regular
intervals by the bits.
Shown in Figures 10 and 11 are further examples of support
posts 16 supporting a rotatable cutter support 18 having cutter
bits 19 thereon. Shown in Figure 11 is two cutter support posts
16, each supporting one end of a shaft 25 upon which a rotatable
cutter support member 18 is mounted. Cutter support member 18 is
shown with cutter bits 19 installed thereon.
. .
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Modifications may be made within the scope of the
appended claims.
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