U.S. patent number 3,904,246 [Application Number 05/440,010] was granted by the patent office on 1975-09-09 for rotary cutter heads for mineral mining machines.
This patent grant is currently assigned to Coal Industry (Patents) Limited. Invention is credited to Albert Graham French, John Albert Gandy.
United States Patent |
3,904,246 |
Gandy , et al. |
September 9, 1975 |
Rotary cutter heads for mineral mining machines
Abstract
A rotary cutter head for mounting on a hollow drive shaft of a
mineral mining machine comprises water powered, air flow inducing
devices mounted remote from the axis of the rotary cutter head.
Inventors: |
Gandy; John Albert (Bircoats
near Doncaster, EN), French; Albert Graham
(Willington, EN) |
Assignee: |
Coal Industry (Patents) Limited
(EN)
|
Family
ID: |
9814471 |
Appl.
No.: |
05/440,010 |
Filed: |
February 6, 1974 |
Foreign Application Priority Data
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Feb 9, 1973 [GB] |
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06437/73 |
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Current U.S.
Class: |
299/81.2;
175/213; 299/87.1; 299/12 |
Current CPC
Class: |
E21C
35/23 (20130101); E21C 25/10 (20130101) |
Current International
Class: |
E21C
35/00 (20060101); E21C 35/23 (20060101); E21C
25/00 (20060101); E21C 25/10 (20060101); E21C
013/04 (); E21C 007/00 (); E21B 021/00 () |
Field of
Search: |
;299/81,89,12
;175/213 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,301,182 |
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Jul 1962 |
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FR |
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1,111,319 |
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Apr 1968 |
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GB |
|
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Stevens, Davis, Miller &
Mosher
Claims
We claim:
1. A rotary cutter head for a mineral mining machine having a drive
shaft extending towards the working mineral face, comprising a hub
assembly drivably mountable on the said drive shaft of the machine,
a cylindrical component secured around the hub assembly, a
plurality of cutter tool holders provided around the periphery of
the cutter head, and ventilating means remote from the axis of
rotation of the cutter head and including air flow guide means and
air flow inducing nozzle means for directing fluid along the said
air flow guide means.
2. A rotary cutter head as claimed in claim 1, in which the
ventilator means is arranged to induce an air flow through the
cylindrical component.
3. A rotary cutter head as claimed in claim 1, comprising a
distributor for feeding fluid fed along the machine's drive shaft
to the air flow inducing nozzle means.
4. A rotary cutter head as claimed in claim 3, in which the
cylindrical component provides a plurality of angularly spaced
chambers, fluid being fed from the distributor to each chamber.
5. A rotary cutter head as claimed in claim 4, comprising dust
suppression nozzle means, the fluid being fed from one of the said
chambers to the air flow inducing nozzle means and to the dust
suppression nozzle means.
6. A rotary cutter head as claimed in claim 1, in which the air
flow guide means extends through the hub assembly to define a
passage which extends between the machine side and the working face
side of the hub assembly.
7. A rotary cutter head as claimed in claim 6, in which the air
flow inducing nozzle means is arranged for directing fluid along
the passage defined by the air flow guide means so that an air flow
is induced away from the machine side of the hub assembly towards
the working face side of the hub assembly.
8. A rotary cutter head as claimed in claim 6, in which the air
flow inducing nozzle means is arranged for directing fluid along
the passage defined by the air flow guide means so that an air flow
is induced away from the working face side of the hub assembly.
9. A rotary cutter head as claimed in claim 8, in which a baffle is
provided on the machine side of the air flow guide means.
10. A rotary cutter head for a mineral mining machine having a
drive shaft extending towards the working mineral face, comprising
a hub assembly drivably mountable on the said drive shaft of the
machine, a cylindrical component secured around the hub assembly, a
plurality of cutter tool holders provided around the periphery of
the cutter head, ventilating means remote from the axis of rotation
of the cutter head and including air flow guide means and air flow
inducing nozzle means for directing fluid along the said air flow
guide means, and an air flow guide plate assembly provided on the
working face side of the hub assembly.
11. A rotary cutter head as claimed in claim 10, in which the air
flow guide plate assembly comprises a circular plate defining an
annular passage adjacent to the inner periphery of the cylindrical
component.
12. A rotary cutter head as claimed in claim 10, in which the air
flow guide plate assembly includes a circular plate which defines a
plurality of angularly spaced passages.
13. A rotary cutter head as claimed in claim 12, in which the air
flow guide plate assembly includes shield means arranged over the
working face end of each of the said angularly spaced passages, the
shield means defining an access to the passage which faces in a
direction opposed to the direction of rotation of the rotary cutter
head.
14. A rotary cutter head for a mineral mining machine having a
drive shaft extending towards the working mineral face, comprising
a hub assembly drivably mountable on the said drive shaft of the
machine, a cylindrical component secured around the hub assembly, a
plurality of cutter tool holders provided around the periphery of
the cutter head, and ventilating means including a plurality of air
flow guides angularly spaced around the cutter head, each of the
air flow guides having an air flow inducing nozzle, the zone
between the hub assembly and a circular plate being divided into a
plurality of compartments, each compartment being associated with
one of the air flow guides.
15. A mineral mining machine having a drive shaft extending towards
the working face, and a rotary cutter head comprising a hub
assembly drivably mounted on the said drive shaft, a cylindrical
component secured around the hub assembly, a plurality of cutter
tool holders provided around the periphery of the cutter head, and
ventilating means remote from the axis of rotation of the cutter
head and including air flow guide means and air flow inducing
nozzle means for directing fluid along the said air flow guide
means.
Description
This invention relates to rotary cutter heads for mineral mining
machines, the cutter heads being drivably mountable on rotary drive
shafts of the machines and having cutter tools mounted around their
outer peripheries for breaking mineral from working faces.
Frequently, when such a cutter head is used to break coal from a
longwall coal face there is a tendency for methane emitted from the
broken coal to concentrate around the cutter head which is
operating in a buttock shielded from the main ventilation air flow.
Such a concentration of methane can be dangerous, especially if the
methane is allowed to collect in the vicinity of the cutting zone
of cutter head until its concentration is within the explosive
range i.e. 8% to 15% of methane. Once the concentration of methane
is within this range it is possible for a spark generated by a
cutter tool striking an intrusion in the coal face to ignite the
methane which in turn could give rise to an explosion.
It is known for a mining machine to have a hollow drive shaft and
for ventilator means comprising a water jet to be provided on the
mining machine which induces a ventilating air flow along the
hollow drive shaft of the rotary cutter head towards the cutting
zone of the cutter head. Unfortunately, the use of such a
ventilator means usually precludes the use of the hollow drive
shaft for feeding dust suppression fluid to the cutter head, the
fluid being distributed to nozzles provided on the cutter head
adjacent to the cutter tools. Thus previously, it has been
necessary to decide whether the hollow drive shaft should be used
for conducting a ventilation air flow or whether it should be used
for feeding dust suppression fluid to the cutter head. If the
hollow drive shaft was used for ventilation then it was necessary
to adopt a less efficient dust suppression system and install the
nozzles for dust suppression fluid on the body of the mining
machine remote from the cutter tools. Alternatively, if the hollow
drive shaft was used for dust suppression purposes it was necessary
to adopt a less efficient ventilating system and mount the
ventilator means remote from the cutter head.
An object of the present invention is to provide an improved cutter
head for a mineral mining machine.
According to the present invention a rotary cutter head for a
mineral mining machine having a drive shaft extending towards the
working mineral face, comprises a hub assembly drivably mountable
on the drive shaft of the machine, a cylindrical component secured
around the hub assembly, a plurality of cutter tool holders
provided around the periphery of the cutter head, and ventilating
means remote from the axis of rotation of the cutter head and
including at least one air flow guide and an air flow inducing
nozzle for directing fluid along the guide.
Preferably, the air flow guide extends through the hub assembly
forming a passage which extends between the machine side and the
working face side of the hub assembly.
The nozzle may be arranged for directing fluid along the guide so
that an air flow is induced away from the working face side of the
hub assembly and in which case a baffle may be provided on the
machine side of the air flow guide.
Alternatively, the nozzle may be arranged for directing fluid along
the guide so that an air flow is induced away from the machine side
of the hub assembly.
The ventilator means may be arranged to induce an air flow through
the cylindrical component and in which case the air flow guide
means may be carried on loading vanes secured around the
cylindrical component.
Advantageously, the rotary cutter head comprises a plurality of air
flow guides. Conveniently a distributor is provided for feeding
fluid fed along the machine's drive shaft to each of the
nozzles.
Preferably, the cylindrical component provides a plurality of
angularly spaced chambers and fluid is fed from the distributor to
each of the chambers.
Advantageously fluid is fed from the chambers to dust suppression
nozzles mounted on the cutter head.
The present invention also provides a rotary cutter head as defined
above in combination with the mining machine.
By way of example only, six embodiments of the present invention
will be described with reference to the accompanying drawings in
which:
FIG. 1 shows a perspective view partly in section of a first
embodiment of rotary cutter head mounted on a mining machine (only
part of which is shown);
FIG. 2 is a diagrammatic sectional view taken along the axis of
rotation of a rotary cutter head which is constructed as the cutter
head of FIG. 1 except that it is of opposite hand to that of FIG.
1, i.e. in use, the head rotates in the opposite direction.
FIG. 3 is a diagrammatic sectional view taken along the line
III--III of FIG. 2;
FIG. 4 is a diagrammatic sectional view taken along the axis of
rotation of a rotary cutter head constructed in accordance with a
second embodiment of the present invention and showing part of the
head only;
FIG. 5 is a diagrammatic sectional view taken along the axis of
rotation of a rotary cutter head constructed in accordance with a
third embodiment of the present invention;
FIG. 6 is a diagrammatic sectional view taken along the line VI--VI
of FIG. 5;
FIG. 7 is an incomplete diagrammatic sectional view taken along the
axis of rotation of a rotary cutter head constructed in accordance
with a fourth embodiment of the present invention, the cutter head
being of the same hand to the cutter head of FIG. 1;
FIG. 8 is an incomplete diagrammatic sectional view taken along the
axis of rotation of a rotary cutter head constructed in accordance
with a fifth embodiment of the present invention;
FIG. 9 is an incomplete diagrammatic end view of the rotary cutter
head of FIG. 8 with an end plate removed;
FIG. 10 is a perspective view of the end plate; and
FIG. 11 is an incomplete diagrammatic sectional view taken along
the axis of rotation of a rotary cutter head constructed in
accordance with a sixth embodiment of the present invention.
Referring firstly to FIGS. 1, 2 and 3 the first embodiment of
rotary cutter head 1 is shown drivably mounted on a hollow drive
shaft 2 of a coal mining machine 3 (only a part of which is shown)
of the well known "shearer" type. In operation such a shearer
machine traverses to and fro along a longwall coal face with cutter
tools 4 mounted around the periphery of the cutter head winning
coal from the working face. The broken coal is loaded by means of
helical loading vanes 5 onto an armoured face conveyor (not shown)
which extends along the face. As the cutter head 1 cuts the face it
forms a buttock in the working face and thereby tends to be
shielded from the main ventilation air flow along the face.
The cutter head 1 comprises a hub assembly 6 drivably mounted on
the drive shaft 2 and retained in position by a spacer 7 and a key
(not shown). A cylindrical component 8 is secured around the hub
assembly and forms a mounting platform for the helical loading
vanes 5 which in turn support cutter tool holders 9 for the cutter
tools 4. The radially inner surface of the cylindrical component is
provided with a plurality of elongated, angularly spaced plates 10
forming chambers 11, the ends of which are closed by end plates 12.
The chambers 11 extend across substantially the whole of the cutter
head and enable pipe connections 13 to be made to virtually any
part of the cylindrical component from a plurality of nozzles 14
for dust suppression fluid provided adjacent to the cutter tool
holders 4.
The rotary cutter head 1 also comprises ventilator means
constituted by a plurality of air flow guides 15, each of which is
formed by two plates 16 provided on the radially inner surface of
the cylindrical component between two adjacent elongated plates 10
and extending from the machine side of the hub assembly to the
working face side of the hub assembly. Although in the described
embodiment the ventilator means comprises seven air flow guide
means, the number could vary from one to more than seven depending
upon the amount of induced ventilation required.
Air flow inducing nozzles 17 are provided for directing fluid along
the air flow guide 15, respectively, each of the nozzles being
mounted adjacent to the wall of the air flow guide and arranged to
direct the fluid along the air flow guide so that an air flow is
induced away from the working face and towards the machine.
A baffle 18 in the form of an annular perforated screen is provided
on the cylindrical component 8 so as to extend across the outlets
of the air flow guides.
The rotary cutter head 1 is provided with distribution means 20 for
the dust suppression fluid. The distribution means comprises a tube
21 which is located within the bore of the hollow drive shaft 2 and
which in use does not rotate with the cutter head and a distributor
22 located on the end of the drive shaft 2 and secured to the hub
assembly 6 by bolts 23. The distributor 22 provides a chamber 24
and passages 25 which interconnect the bore of the tube 21 to
distribution pipes 26 which feed fluid to the chambers 11 and to
the air flow inducing nozzles 17.
In addition a conical cover plate 29 is secured by brackets 31
(only one of which is shown) to the cylindrical component 8 to
protect the fluid distribution and ventilator means from being
damaged by broken mineral. Also air flow guide means in the form of
an annular plate 32 and an extractor duct 33 are provided on the
body of the machine 3 for extracting air away from the rotary
cutter head. An extraction fan (not shown) is secured to the
extraction duct 33.
In operation, as the machine 3 traverses along the working face
with the rotary cutter head 1 winning coal from the working face,
fluid is fed through the bore of the tube 21 to the distributor 22
located on the end of the shaft 2. The fluid is then fed via the
chamber 24 and passages 25 along the radial distribution pipes 26
to the chambers 11 on the cylindrical component and to the nozzles
17. In the embodiment shown the fluid is fed continuously to all
the radial pipes. Alternatively, the distribution means may be
provided with a component which is mounted on the end of the tube
21 within the chamber 24 and which selectively feeds fluid to only
those distribution pipes 26 currently within a preselected sector
e.g. to only those distribution pipes 26 within the cutting zone of
the rotating cutter head. Thus as the head rotates fluid is fed
sequentially to those chambers associated with the cutting zone of
the head and when a chamber leaves the cutting zone its supply of
fluid is cut off by the distribution means until it re-enters the
cutting zone.
Fluid is fed from the chambers 11 along the pipes 13 to the dust
suppression nozzles adjacent to the cutter tools 10 associated with
the cutting zone. The water is directed from these nozzles towards
the cutting tools to suppress the dust produced by the breaking
mineral.
The flow of fluid along each of the guides 15 from the associated
nozzle 17 induces an air flow along the guide in a direction away
from the working face and the cutter tools 4 and towards the baffle
18. As the induced air/fluid flow impacts on the baffle 18 the dust
particles which were not suppressed by fluid from the nozzle 14
adjacent the cutting zone and which were extracted with the air
flow from the cutting zone tend to be arrested and fall with the
fluid impacting on the baffle 18 towards the mine floor. The air
flow passes through the baffle 18 and is drawn through the
extraction duct 33 to be discharged into the main ventilation air
stream at a point remote from the cutting zone ensuring no
recirculation if possible. Arrows X indicate the induced air flow
in the zone adjacent to the working face, the flow passing through
a gap 34 provided between the radially inner surface of the
cylindrical component 8 and the radially outer edge of the cover
plate 29.
It will be seen from the above description that the first
embodiment of the present invention provides a rotary cutter head
which continuously enables a high dust suppression efficiently to
be achieved and which enables the zone around the head to be
continuously ventilated. Any methane discharged from the broken
coal is extracted from adjacent the cutter head and discharged into
the main ventilation air stream. Thus, dangerously high
concentrations of methane tend to be prevented from forming in the
vicinity of the cutting zone.
FIG. 4 shows a second embodiment of rotary cutter head 1 in which
the air flow inducing nozzles 17 (only one of which is shown) of
the ventilator means are arranged to direct fluid along the air
flow guides 15 in a direction towards the working face. With such
an embodiment the induced air flow through the guides 15 is flowing
towards the cutting zone and so it is not laden with dust
particles. Thus no removal of dust particles is required at this
stage and so no baffle 18 is provided.
The air flow discharging from the air flow guides 15 is directed
towards the cutting zone via the annular gap 34 between the
cylindrical component 8 and conical cover plate 29. The air flow
enters the zone adjacent to the working face, scrubbing the working
face and tending to remove substantially all the methane discharged
from the broken coal and from the freshly formed working face.
Thus, the second embodiment of rotary cutter head provides very
efficient means for ventilating the zone adjacent to the cutter
head. Dust suppression is achieved by the nozzles 14 arranged
adjacent to the cutter tools 4 and also by the fluid discharged
from the nozzles 17 which flows with the induced air flow through
the annular gap 34 towards the cutting zone.
FIGS. 5 and 6 show the third embodiment of rotary cutter head which
is similar to the first embodiment of cutter head described with
reference to FIGS. 1, 2 and 3 but which has additional ventilator
means mounted on the helical loading vanes 5 so as to induce an air
flow through the cylindrical component towards the hub assembly.
The additional ventilator means comprises a plurality of radial
hollow members 40, each of which extends through the cylindrical
component 8 to provide a passage extending from a window 41 formed
in the wall of the member 40 to the zone adjacent to one of the air
flow guides 15. An air flow inducing nozzle 42 is provided within
each of the members 40 and arranged to direct fluid towards the
adjacent air flow guide 15. The radially outer end of each of the
members 40 is closed and fluid is fed to the nozzles 42 from the
chambers 11 via passages 13 extending radially along the loading
vanes 5.
In use when fluid is fed to the nozzles 17 and 42, dust laden air
is induced along the members 40 towards the air flow guides 15
where together with the induced air through the gap 34 it is
induced along the air flow guide 15 towards the baffle 18.
Thus, as with the first described embodiment an air flow is induced
away from the cutting zone of the cutter head, the flow tending to
ventilate the zone around the head and preventing methane from
forming dangerously high concentrations within this zone.
FIG. 7 shows a fourth embodiment of rotary cutter head constructed
in accordance with the present invention, in which ventilator means
are provided on radial surfaces adjacent the helical loading vanes
5. The ventilator means comprise a plurality of hollow members 50
which are somewhat similar to the members 40 of the third
embodiment previously described with reference to FIGS. 5 and 6 but
which instead of extending through the cylindrical component 8 are
arranged to guide an induced air flow adjacent the outer surface of
the cylindrical component towards the machine side of the cutter
head. In the embodiment shown in FIG. 7 the members 50 are "L"
shaped but in modified constructions the members may be curved or
inclined with respect to the radial direction of the cutter
head.
The members 50 may extend to the machine side of the cutter head or
alternatively may extend adjacent to only a portion of the loading
vanes.
In further modification of this embodiment the ventilation means
may comprise only one member 50. Alternatively one member 50 may be
provided on each loading vane. As a further alternative more than
one member 50 may be provided on each of the loading vanes.
FIGS. 8, 9 and 10 show a fifth embodiment of rotary cutter head in
which the air flow inducing nozzles 17 of the ventilator means are
arranged to direct fluid along the air flow guides 15 in a
direction away from the working face and towards the body of the
mining machine (not shown). The dust laden air is induced through
passages 60 (see FIGS. 8 and 10) which are formed in a circular
cover plate 61 and each of which has an elongated cross-sectional
area extending radially towards the periphery of the cover plate
61, along the air flow guides 15 towards an extraction duct 62
which is mounted on the machine body (not shown) and which has an
annular plate 64 extending along and adjacent to the inner
periphery of the cylindrical component 8 in order to provide an
effective seal against air leakage. Thus, substantially all the
induced air flow is extracted along the extraction duct 62.
The working face side of each of the passages 60 is provided with a
shield arranged over the passage to define an access to the passage
which faces in a direction transverse to the axis of rotation of
the rotary cutter head and in the direction opposed to the
direction of rotation of the rotary cutter head. Such an
arrangement of the passage access tends to prevent cut mineral from
entering the passages but permit free entry of the induced dust
laden air flow.
The air flow inducing nozzles 17 are fed with fluid from ducts 65
formed adjacent to the loading vanes 5 (omitted from FIG. 9). The
nozzles are removable from the cylindrical component 8 to enable
them to be easily cleaned or unblocked during use.
As can be seen in FIG. 9 the ventilating means comprise three air
flow guides 15 equally spaced around the inner periphery of the
cylindrical component 8. In FIG. 9 the cover plate 61 has been
removed to expose the hub 6. The zone between the hub 6 and the
cover plate 61 is divided into three equal compartments 66 by
radial fins 67 secured to the hub 6 and to the inner periphery of
the cylindrical component 8, and an annular plate 68 secured to the
hub 6. The fins 67 sealably engage resilient pads 69 (see FIG. 8)
secured to the cover plate 61 and a sealing ring 70 abuts the end
of the annular ring 68. Thus, in use when the cover plate 61 is
assembled on the rotary cutter head, the three compartments are
separate from one another and if any one of the air flow guides
should become inoperative (for example due to a blocked nozzle 17)
there is little or no possibility of the induced air flow being
recirculated between the operative and the non-operative air flow
guides.
FIG. 11 shows a sixth embodiment of rotary cutter head in which the
air flow inducing nozzles 17 (only one of which is shown) of the
ventilator means are arranged to direct fluid along the air flow
guide 15 in a direction towards the working face to ventilate the
cutting zone of the cutter head. The induced air flow passes
through the annular space 34 towards the outer periphery of the
cutter head.
It will be seen from the above description that the present
invention provides simple, reliable means for ventilating the zone
adjacent to a rotary cutter head and for suppressing dust generated
during cutting.
* * * * *