Note: Descriptions are shown in the official language in which they were submitted.
lZ;Z4503
TITLE
"A holder for a pick, and the combination of a
pick and holder"
TECHNICAL FOE LO AND BACKGROUND ART
This invention relates to pick holders and the
combination thereof with picks and is particularly
concerned with the art of mineral mining picks (which
term, as is generally acknowledged in the art,
includes picks for rock mining and road planing).
In this art the pick holder is likely to be in the
form of a socketed block or box on or in a driven
component of a mining machine but may be the
component itself.
The invention is concerned with picks and pick
holders of the type in which, during their use, a
fluid usually water and conveniently referred to as
such hereafter) is directed into the cutting region
of the picks for the primary purposes of dust
suppression, flushing and cooling (which latter
term includes cooling incentive sparking).
Examples of picks and pick holders of this
general type are disclosed in our GOB. Specification
No. 2,088,441 which is concerned
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with the way in which the flow of water under pressure
can by achieved through the pucker the aforementioned
purpose sin an efficient manner. The advantages
of providing a relatively simple and efficient
mean of achieving flow of water under pressure
through a pick and the appropriate application of
the resultant water spray or jet for the aforemention-
Ed purposes are discussed in our GO Specifications
Nos. 2,088~441 and 82 03 638. It is most
- 10 desirable that the water spray or jets emanating
from the pick and pick holders are utilized
e~iciently and controlled to alleviate the presence
of excessive water at the mineral mining site.
With this in mind it has hitherto been proposed to
incorporate in the mineral mining machinery valve
means by which water supply for dust suppression,
flushing or cooling is provided only when required
or those purposes. In a conventional coal shearer
drum the picks are secured in holding blocks which
are helically spaced around the peripheral edge
of a helical web or flange on the drum. During
rotation of the drum for cutting, the picks are
only in engagement with the mineral face for a
minor arcuate portion of the drums rotation and in
a prior proposal the valve means is incorporated in
the drum to restrict the supply ox water so that
the spray or jets are provided only for those
picks which at a given instant are passing through
the aforementioned minor cutting arc. It has
also been proposed to provide water sprays or jets
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from nozzles on picks and pick holders and to have
valve means in the holder or carried by the pick
which is responsive to pressure of cutting on the
pick so that a water supply is available for the
spray or jet on that pick or holder only for the
period during which the pick is in cutting engagement
with the mineral face; examples of these proposals
are to be found in European Specifications Nos.
0 010 534 and 0 060 827 and in GOB. Specification
No. 2,077,813 A.
The valve means in the prior proposals of the
European Specifications are relatively complicated
in operation and design, expensive to manufacture and
assemble and because of their complicated structure
(which calls for precision made valve components)
will require frequent servicing and replacement.
Where it is proposed that the valve means is carried
by the pick (as in European 0 060 827) it will be
realized, because of the limited useful working life
expected for mineral mining picks, the aforementioned
considerations of cost and complexity of design are
likely to render the proposal particularly
unattractive and unacceptable commercially.
The proposal in the aforementioned GOB. AYE
is for a relatively simple form of valve means
comprising a resilient sleeve on the pick shank which
sleeve is deformed in response to cutting pressure
on the pick to admit water to the nozzle. A
necessary feature of this proposal is that the socket
in the pick box which receives the pick shank us
enlarged to permit the required deformation of the
sleeve; this calls for expensive machining of` the
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box and has the urethra disadvantage that the cavity within which
the sleeve it received can collect coal (or like) dust which will
impair the resilient deformation of the sleeve. There are the
further disadvantages that the sleeve will likely have a very
short useful life, will exhibit poor sealing characteristics, and
may easily be damaged during handling of the pick and its
insertion into the pick box by virtue of its exposed position on
the pick shank.
It is an object of the present invention to provide a
holder for a pick and the combination of a pick and holder which
provides for water supply through the pick for dust suppression,
flushing or cooling purposes during cutting and also provides a
relatively simple, inexpensive and efficient means of controlling
that water supply in a manner which alleviates the disadvantages
of the aforementioned prior proposals.
STATEMENT OF INVENTION AND ADVANTAGES
_ .
According to the present invention there is provided a
holder for a mineral mining pick comprising a longitudinally
extending shank socket within which a shank of a mineral mining
pick is to be longitudinally received, a tubular spigot located
within and extending longitudinally from a bottom wall of said
shank socket, said tubular spigot being secured directly to the
bottom wall of the shank socket and having a longitudinally
extending bore in fluid flow communication with a fluid supply
passage in the holder and being intended for mating in fluid
sealing engagement with a longitudinally extending fluid coupling
socket in the pick shank of a pick which is slid ably received in
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the shank socket for the supply of fluid through said bore to
passage means in the pick for dust suppression, cooling or
flushing purposes' valve means for controlling fluid flow through
the bore of said tubular spigot, said valve means comprising
longitudinally extending rod means mounted in the bore of said
tubular spigot and longitudinally displaceable relative thereto
to open and close fluid flow through said bore, said rod means
being responsive to longitudinally directed forces applied
thereto from a pick held by the holder during use for mineral
mining to open said fluid flow through the bore when said forces
exceed a predetermined value.
Further according to the present invention there is
provided the combination of a mineral mining pick and a pick
holder, said pick comprising a body having a head with a cutting
part, a shank integral with the head part and which extends
longitudinally from the head, a fluid coupling socket extending
longitudinally within the shank from the end thereof remote from
the head and passage means in the body communicating with the
coupling socket for the flow of fluid under pressure to an outlet
port by which fluid is directed for dust suppression, cooling or
flushing purposes; said pick holder comprising a shank socket
within which the shank is longitudinally received, and a tubular
spigot located within said shank socket and extending
longitudinally from a bottom wall of the shank socket, said
tubular spigot being secured directly to the bottom wall of the
shank socket and having a longitudinally extending bore in fluid
flow communication with a fluid supply passage in the holder;
B
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said fluid coupling socket longitudinally receiving the tubular
spigot during insertion of the shank into the shank socket to
provide fluid flow communication through the bore of the tubular
spigot and between the fluid supply passage and the passage
means; retaining means for releasable retaining the shank in the
shank socket, and valve means for controlling fluid flow through
the bore of the tubular spigot, said valve means comprising
longitudinally extending rod means mounted in the bore of the
tubular spigot and longitudinally displaceable relative thereto
to open and close fluid flow through said bore, said rod means
being responsive to longitudinally directed forces applied to
said rod jeans from the pick during use of the combination in
mineral cutting to actuate the valve means and open fluid
communication through the bore when said forces exceed a
predetermined value.
The present invention was primarily developed as an
improvement to the invention which is the subject of our GO
Specification Jo. 2,08~,441 which is concerned with achieving a
simple and efficient water coupling between a pick and its holder
so that a water spray or jet can be effected through an outlet
port in the pick body. By the present invention the tubular
spigot/coupling socket water coupling of our earlier proposal may
have associated therewith a relatively simple and efficient valve
arrangement by which it is intended that water supply to the
outlet port in the pick body should be effected substantially for
the period during which the pick is in cutting engagement with
the mineral face and should automatically be cut off as the pick
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2~503
moves out of cutting engagement with the mineral face. From the
foregoing it will be apparent that the actuator for controlling
the valve means is intended to be responsive to the increased
force to which the pick is subjected as it moves into engagement
with the mineral face and cuts through that face so that the
water supply is available at the jet or spray and upon removal or
reduction of the aforementioned force (as the pick moves out of
act. '
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cutting engagement with the mineral the actuator
responds in the opposite sense so that the
valve shuts off water flow to the jet or spray.
Preferably toe actuator is longitudinally displaceable
in response to the aforementioned forces which are
applied to the pick and there through to the holder)
during cutting and upon the reduction of those ~orceq
as the pick moves out of cutting engagement wit the .
mineral face
. To apply the differential in forces to the
actuator during a mineral cutting and non-cutting
sequence, particularly where the actuator is
longitudinally displayable, it is preferred that
the pick when received in the pick holder it
capable of restricted longitudin21 displacement
relative to the holder so that relative longitudinal
displacement between the pick and the pick holder
causes a force differential to be applied to the
actuator (preferably longitudinally displacing tot
actuator) to control the opening and closing ox the
valve means. Preferably therefore the means for ret-
awning pick shank in the shank socket of the pick
holder is arranged to permit the required relative
longitudinal displacement between the pick and the
holder for operation of the valve means. Several
forms of retaining means can be provided as are
well known in the art but preferably it is
constructed so that a shoulder
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on the spigot. engages with a resilient writing
. component into coupling socket to restrain
- ' withdrawal ox the pick shank from the shank socket
Bearing in mind the aforementioned preference ox
5 the pick being longitudinally displaceable relative '
tooth pick holder within predetermined limits as .
' determined by the retaining means, biasing means
., , should be provided which urges thy pick outwardly
... . . . . _ _ . .. .. ... .. . .
from the socket yin the pick holder to the extent
10 permitted by the retaining means. By this latter
proposal, when the pick engages the mineral face or
cutting it is displaced into the shank socket ox the
holder under the cutting ore against the biasing
mean and this displacement results in the Allah
means being adjusted to open communication fur water
. flow through to the outlet port in the pick. The
biasing means which urges the pick outwardly .'
preferably comprises fluid pressure to which the
pick is subjected from the holder. If required
however the aforementioned biasing means can be
provided by a spring component or other resilient
means reacting between the pick and the pick holder:
It roared, the tubular spigot can serve as the
actuator Wheaties responsive to a longitudinally
directed force applied thereto during use of the pick/
holder in mineral cutting to control operation of the
valve means. Preferably however the actuator
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lZ24503
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is a component separate from the tubular spigot
but which is conveniently housed in the bore of the
tubular spigot to be subjected to the cutting and
non-cutting forces as a result ox which it is
longitudinally displaceable to open and close the
valve means. In a preferred arrangement the
actuator comprises a rod-like component carried
within the bore of the tubular spigot to extend
there through so that one end of the actuator is
10. subjected to the longitudinally directed forces
applied between the pick and the pick holder upon
and during cutting engagement of the pick with the
mineral race and the subsequent clearance oath
pick from the mineral face while the other end of
the actuator adjusts a valve member which is
displaceable in sympathy with the actuator to open
or close the valve means between the outlet port
and the water source depending upon the forces which
are applied to the pick.
Where the pick and pick holder are capable of
restricted longitudinal displacement relative to
each other, it is likely that a longitudinally
varying clearance will be provided between the
- opposing faces of the pick holder and the head of
the pick and within which clearance detritus can
collect (which would eventually prevent the alone-
mentioned relative displacement). To alleviate
this problem it is preferred that the pick head and
pick holder are bridged by a seal such as a sleeve,
30 Lowry ring or similar component- which effectively
closes the aforementioned clearance to entry by
12;~5()3
1 o
detritus.
DRAWINGS
One embodiment of a mineral mining pick and a
pick holder combination constructed in accordance
with the present invention will now be described,
by way of example only, with reference to the
accompanying illustrative drawings, in which:
Figure 1 is a side elevation of the combination
in part section where a tubular spigot is
carried by the pick holder and the valve
means is carried by said tubular spigot;
Figure 2 is a side elevation in part section
of the tubular spigot incorporated in the
combination of Figure 1;
Figure 3 is a side elevation of a rod part of
the actuator for the valve means incorpor-
axed in the combination of Figure 1;
Figure 4 is a side elevation of a flow disturb-
tutor head for attachment to the rod part
of Figure 3;
Figure 5 is an end elevation of the distributor
head shown in Figure 4, and
Figures 6 and 7 diagrammatically show the
combination in conditions, respectively,
in which fluid flow through the pick it
closed by the valve means and is opened
by the valve means.
DETAILED DESCRIPTION OF DRAWINGS
The combination shown in Figures 1, 6 and 7 is
primarily intended for heavy duty coal cutting and
comprises a point attack pick 1 mounted in a pick
holder 2. The pick 1 is generally of conventional
1224S03
shape comprising a one piece steel body having a
head 3 and a shank 4 which extends longitudinally
from the head 3. The shank 4 may be of any
lateral cross section but will usually ye polygonal,
rectangular or, as considered in the present
embodiment, circular. Mounted in the head 3 is a
tungsten carbide insert 5 which forms a cutting
part or tip to the pick. Provided in the holder 2
is a cylindrical shank socket 6 which receives the
cylindrical shank 4 in substantially complementary
manner, the shank being inserted longitudinally
into the socket 6 through the mouth thereof.
The pick holder 2 will usually be in the form
of a block or box as shown which is secured for
movement as part of a coal cutting machine to
displace the cutting tip 5 as appropriate for coal
cutting. Usually the holder 2 will be secured to
a coal shearer drum pa which is rotatable about
its longitudinal axis to effect cutting with the
pick 1 retained in the holder to project outwardly
of the drum at a calculated angle of attack to the
coal face. If required, the holder 2 can be an
integral part of the drum pa.
Formed within the body of the pick 1 it a
passage 11 which extends longitudinally through the
shank 4 and into the head 3 where it communicates
with outlet ports 12 formed between. recesses in
the side face of the insert 5 and an opposing
face of a bore within the head 3 within which
bore the insert 5 is mounted (preferably in
accordance-with the-invent-ion which is the subject
of our GO Specification No. 2,087,949). The
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- 12 -
passage lo is intended for the flow there through of
water which is primarily intended for the purposes
of dust suppression, flushing and cooling during
coal cutting. Generally the water will emanate
from a source within the coal shearer drum pa and
consequently provision is made within the pick
holder 2 for coupling the water supply to the pass-
age 11 This coupling includes a tubular spigot
13 upstanding from the bottom wall 14 of the socket
6 and concentric with that socket. The spigot 13
is received within a water coupling socket 15
which is formed in the free end of, and concentric
with, the pick shank 4 and which is an extension
of the passage 11 The bore 16 of the tubular
spigot communicates with the passage 11 and coup-
rises part of a water supply passage aye from the
source of water under pressure within the drum pa.
Located within an annular recess 17 in the socket
15 of the pick shank is an annular pressure seal/
retainer component 18 of resilient material.
The recess 17 provides a convenient means for
retaining the component 18 longitudinally in the
socket 15 for carriage with the pick but it will
be appreciated that alternative means of such
retention can be provided-. The component 1
forms a water seal between the
tubular spigot 13 and the pick shank 4
and also serves as part of retaining
lZ~'4S~)3
13
means by which the pick shank 4 is retained in its
socket I. It will be realized from the drawing
that the tubular spigot 13 will automatically mate
with the fluid coupling socket 15 and pass through
the sealing component 18 to effect the water seal
as the shawls 4 is inserted longitudinally into the
shank socket 6.
A further part of the aforementioned retaining
means is provided by a frost conical head 7 of the
tubular spigot 13, the taper of which provides 2
lead-in surface during mating of the spigot with the
socket 15 and the mov~nent of the head of the spigot
through the sealingJretaining component 18.~ The
head 7 has an annular shoulder 8 which, when the
spigot 13 is fully inserted into the coupling socket
15 lies adjacent to the component assay shown in
Figure Sue that abutment of this component against
the shoulder 8 restrains the pick 1 from being
withdrawn from the pick holder 2. When the pick 1
is inserted to its maximum extent in the holder 2
a longitudinal clearance is provided between the
shoulder 8 and the resilient component 18 so that
this clearance can be taken up to permit relative
longitudinal displacement between the pick and its
holder which longitudinal displacement will be slightly
increased by a small amount of deformation of the
resilient component 18 during its abutment by the
shoulder I) so that a gap or clearance A will open
and close between the end face of the pick holder 2
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and an annular face which opposes it on the pick
head 3 which is formed between the pick head and
the shank 4 (see figures 6 and 7). The retaining
means provided by the shoulder 8 on the tubular
spigot 13 and the resilient sealinglretaining
component 18 permits the pick 1 to be removed from
the holder 2 by the application of an excessive
longitudinally directed force to the pick which is
sufficient to move the shank 4 of the spigot 13 by
resilient deformation of the component 18 (and
possibly removing that component from the socket 15).
The tubular spigot 13 is integral with a
tubular mounting 19 by which it is carried in the
! holder 2. The mounting 19 has a male thread which
engages with a female threaded bore 20 in the
holder, the bore 20 being an extension of the
water supply passage aye. An annular seal 21
is provided between a shoulder of the mounting 19
and the bottom wall 14 of the shank socket.
The spigot 13/mounting 19 component carries a
valve which controls the supply of water from the
passage aye to the passage 11 and thereby to the
outlet ports 12; this valve comprises a longitude
finally extending actuator in the form of a rod 22
mounted within the bore 16 of the spigot. Suffice
tent clearance is provided to ensure that the rod 22
and spigot are displaceable longitudinally relative
to each other and that an adequate flow of water is
permitted between the bore 16 and the opposing
surface of the rod 22. The rod 22 emerges from
the tubular-spigot 13 into an `enIarge~.bore-part
23 of the tubular mounting 1g and carries a valve
12~03
- 15 -
head 24 and sealing washer 25 within this bore part
23. By longitudinal displacement of the valve head
24 with the rod 22 so that the washer 25 is urged
into abutment with a bottom shoulder aye in the
tubular mounting 19, a water seal is provided
between the bore part 23 and the bore 16 of the
tubular spigot (thereby closing water communication
between the passages aye and 11~. The rod 22
extends from the bore of the spigot 13 into the
coupling socket 15 and has fitted thereto a
retaining head 26 provided with longitudinally
extending external splints 27. The head 26 is
intended to abut an annular shoulder 28 at the
! bottom of the socket 15 to cause displacement of
the rod 22 in a sense (downwardly as shown in Figure
7) which lifts the valve head 24 off the shoulder in
the mounting 19 to open water communication between
the passages aye and 11. During abutment between
the rod retaining head 26 and the shoulder 28 in the
pick shank, the splints 27 ensure that water flow
communication is maintained between the socket 15
and the passage 11. The head 26 conveniently has
a bore 28 by which it is fitted and secured to a
complementary end 29 of the rod 22 following
insertion of the rod through the tubular spigot.
If required, the mouth of the bore 23 to the
tubular mounting 19 can be provided with a water
filter 30.
In use of the combination shown in Figure 1
a supply of water under pressure is provided to the
supply passage aye and the-water pressure provides
a biasing force on the valve head 24 and on the
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pick 1. More particularly (see Figure 6) the
water pressure urges the valve head 24 into sealing
engagement with the shoulder aye in the mounting 19
while the rod 22 is urged longitudinally so that its
head 26 abuts the shoulder 28 in the coupling socket
of the pick shank. This latter abutment applies
a biasing force to the pick to urge it longitudin-
ally in a direction outwardly of the shank socket 6.
In addition, the rotation of the coal shearer drum
can provide a centrifugal biasing force which also
urges the pick to be displaced in a direction
outwardly of the shank socket 6. Because of
the aforementioned biasing forces it will be
appreciated that when the pick 1 is out of cutting
! 15 engagement with a mineral face, the pick will be
displaced outwardly from its holder 2 to provide a
maximum clearance A and to an extent permitted by
the abutment of the shoulder 8 on the tubular spigot
against the resilient sealing/retaining component
18 as shown in Figure 6. In this latter condition
the valve head 24 will be fully seated and sealed
in the tubular mounting 19 to close water flow
communication between the bore part 23 and the spigot
bore 16 so no water jets or spray emanate from the
outlet ports 12. As the pick 1 moves into cutting
engagement with the mineral face, the forces to
which it is subjected during such cutting will
cause the pick to be displaced longitudinally into
its holder 2 to take up the clearance A as shown
in Figure 7. During this latter displacement the
abutment of the shoulder 28 on the -retainer head 26
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causes the rod 22 to be displaced longitudinally in
sympathy with the pick 1 thereby lifting the valve
head 24 from its seating in the mounting 19; the
valve is consequently opened and immediately
permits the flow of water from the supply passage
aye, through the spigot bore 16 and passage 11 to
provide water jets or sprays aye at the outlet ports
12 for flushing, cooling or dust suppression purr-
owes. Although during the opening of the valve
to permit water flow the valve head 24 (and
immediately the valve head 24 has lifted from its
seating), the pick 1 will be subjected to a
biasing effect provided by the water pressure in the
passage 11 and on face 28, the cutting force applied
to the pick during its engagement with the mineral
face will be considerably greater than this biasing
force so that the valve will open immediately as
effective mineral cutting commences. Following
a cutting stroke of the pick, and as the pick
moves out of cutting engagement with the mineral
face, the removal of the cutting forces will again
permit the pick to be displaced outwardly from its
holder 2 by the previously discussed biasing
forces and to the condition shown in Figure 6 so that
the valve head 24 can again seat against the shoulder
aye of the mounting 19 to close the valve and
cut-off the water supply to the outlets 12.
- During the opening and closing of the clearance
A it is possible that detritus may enter this
clearance and eventually prevent the pick from
exhibiting the longitudinal displacement relative
to the pick holder which is required to operand
12Z9~5()3
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close the valve. To alleviate this possibility a
cylindrical sleeve 31 can be provided to bridge
the pick head 3 and the pick holder and to cover
the clearance A.
During use the shank socket 6 can be subjected
to considerable wear so if required the socket 6
may be provided with a replaceable lining such as
a sleeve 32 conveniently formed as a mounding in
plastics material). The sleeve 32 is a substant-
tally complementary fit within the shank socket 6
to be readily removable therefrom and receives the
shank 4 in substantially complementary manner.
Naturally the sleeve 32 will be subjected to wear
during use of the pick 1 and when necessary it can
be replaced at relatively little expense. As
shown in Figure 1 the bridging sleeve 31 is convent
gently clamped between the replaceable sleeve 32
and the body a the pick holder but it required
the sleeves 31 and 32 can be integral. It will be
realized that the sleeves 31 and 32 are optional
and accordingly have been omitted from Figures 6 and
7. It will also be realized that one or more
outlet ports which communicate with the passage 11
can be positioned where required on the pick head
and other than as indicated by the ports 12.
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A particular feature of the concept of the present
invention where the valve means is mounted in the tubular spigot
is that the fluid spray system is self-sealing for a particular
pick holder in the event that the pick in that holder becomes
ineffective (for example if the pick is inadvertently lost during
use, or becomes broken, or even if a pick is not inserted into
the holder initially). This self-sealing provides a considerable
advantage by ensuring that adequate fluid pressure can be
maintained for other pick/holder combinations on the cutting head
of a mineral wining machine: failure to maintain this pressure
can render the whole system ineffective.
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