U.S. patent application number 12/692174 was filed with the patent office on 2011-07-28 for rack bar haulage system with an improved rackbar to line pan connection.
This patent application is currently assigned to JOY MM DELAWARE, INC.. Invention is credited to Nigel Hill, Gordon Powell.
Application Number | 20110181095 12/692174 |
Document ID | / |
Family ID | 43769355 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110181095 |
Kind Code |
A1 |
Hill; Nigel ; et
al. |
July 28, 2011 |
RACK BAR HAULAGE SYSTEM WITH AN IMPROVED RACKBAR TO LINE PAN
CONNECTION
Abstract
A disclosed rack bar system utilizes a forged or cast clog with
integral lugs that accept a retainer plate. The plain rack bar pins
cannot pass fully through the clog and are held in place by a plate
retainer. The retainer is simply secured by a spring pin, or is
held in place by gravity.
Inventors: |
Hill; Nigel; (Eckington,
GB) ; Powell; Gordon; (Malvern, GB) |
Assignee: |
JOY MM DELAWARE, INC.
Wilmington
DE
|
Family ID: |
43769355 |
Appl. No.: |
12/692174 |
Filed: |
January 22, 2010 |
Current U.S.
Class: |
299/43 |
Current CPC
Class: |
E21C 29/02 20130101 |
Class at
Publication: |
299/43 |
International
Class: |
E21C 29/02 20060101
E21C029/02; E21C 35/12 20060101 E21C035/12 |
Claims
1. A rack bar haulage system forming part of a drive system for
moving the mining machine along a conveyor, said rack bar haulage
system including a plurality of rack bars, each having spaced apart
gear teeth extending between cheek sections at opposite sides of
the rack bar, and a downward extension, a clog having a width
corresponding to the width of the downward extension, and the clog
defining a cavity for engaging and providing support for the rack
bar by receiving the downward extension, the cavity being defined
by two spaced apart bracket sidewalls, and end walls connecting the
sidewalls, openings through the sidewalls, a pin being insertable
through one sidewall opening and being received in the other
sidewall opening, the other sidewall opening being smaller than the
end of the pin, and the other sidewall opening forming a pocket
that receives the end of the pin, the other sidewall opening not
permitting the pin to pass through the other sidewall opening.
2. A rack bar haulage system in accordance with claim 1 wherein the
lugs include a pin for retaining the plates within the lugs.
3. A rack bar haulage system forming part of a drive system for
moving the mining machine along a conveyor, said rack bar haulage
system including a plurality of rack bars, each having spaced apart
gear teeth extending between cheek sections at opposite sides of
the rack bar, and a downward extension, a clog having a width
corresponding to the width of the downward extension, and the clog
defining a cavity for engaging and providing support for the rack
bar by receiving the downward extension, the cavity being defined
by two spaced apart bracket sidewalls, and end walls connecting the
sidewalls, openings through the sidewalls, a pin being insertable
through one sidewall opening and being received in the other
sidewall opening, the other sidewall opening being smaller than the
end of the pin, and the other sidewall opening forming a pocket
that receives the end of the pin, the other sidewall opening not
permitting the pin to pass through the other sidewall opening, the
clog further including means for receiving a plate for retaining
the pin within the first sidewall opening, the means for retaining
the plate comprising spaced apart lugs attached to one side of the
one sidewall, the lugs including opposed slots that receive the
ends of the plate.
4. A rack bar haulage system in accordance with claim 3 wherein the
lugs include a pin for retaining the plates within the lugs.
Description
BACKGROUND
[0001] This disclosure relates to rack bar haulage systems and the
means by which the rack bars are secured and retained to armor face
conveyors, in particular, though not necessarily exclusively, for
underground longwall mining.
[0002] Longwall conveyors normally operate with a powered
coal-cutting machine, a shearer that is mounted onto the face
conveyor. The shearer hauls itself along the face conveyor in both
directions by means of a haulage system. A rack bar haulage systems
comprise a series of rack bars pinned to support brackets, called
clogs, welded to the individual armor face conveyor elements, the
line pan. The shearer engages with the racks via a shoe that
permits free movement in the direction of shearer travel only. The
shoe also houses a drive sprocket that engages the rack teeth to
provide the required haulage load to cut the mined material. The
shearer drive gear wheel meshes with uniformly spaced horizontal
teeth extending between two spaced apart cheek plates to form the
rack bar.
[0003] All rack systems must withstand shearer haulage forces in
various directions and their retention methods must cope with the
tendency of the shearer shoe to bulldoze material in front of it as
it passes along the conveyor.
[0004] In conventional longwall mining, as illustrated in FIGS. 1-2
taken from US Lanfermann et al U.S. Pat. No. 4,155,600, a drum
cutter mining machine 1 is traversed along a face conveyor 2 by
means of a driving wheel 3 secured to a longwall shearer 4. The
driving wheel 3 meshes with a gearwheel or drive sprocket 5 that is
rotatably supported on the machine frame 6 forming part of the drum
cutter-mining machine. The teeth of the drive sprocket 5 mesh with
rack gear teeth of a rack bar or device 7.
[0005] As illustrated in FIG. 2, the face conveyor 2 is made up of
a plurality of conveyor pan sections or line pans 9 joined together
end-to-end by connecting elements 8. By means of these connecting
elements, the conveyor pan sections are maintained movable with
respect to each other so that the conveyor pan sections are
adaptable to characteristics of the mine floor. The individual
conveyor pan sections are connected together by the connecting
elements 8 to provide not only limited mobility with respect to
each other in the horizontal direction of the conveyor 2, but also
to provide vertical or horizontal angling of one conveyor pan
section with respect to another when set on the mine floor. The
rack device 7 that is mounted onto the face conveyor 2 undergoes
the same horizontal motions as the conveyor pan sections. When the
face conveyor is shifted, the rack device also undergoes the same
vertical angular motions which the conveyor pan sections undergo
particularly when it is desired to work undulating portions of a
mine seam. The rack device 7 includes a plurality of elongated rack
bars consisting of movable rack bars 7a and immovable rack bars 7b.
Holders or clogs 10 that are directly or indirectly connected to
the face conveyor 2 support all the rack bars. Connecting bolts 11
are used to join the individual rack bars to the clogs 10.
[0006] The movable and immovable rack bars 7a and 7b, respectively,
of the rack device 7 are provided at both ends of each segment with
a nose-shaped extension 12 which projects downwardly. This
extension includes a bore for accommodating a connecting bolt 11
forming a pivot shaft. As shown in FIG. 1, the movable rack bars 7a
bridge a joint A between the conveyor pan sections. The movable
rack bars 7a are mounted onto the same two holders 10 which are
used to mount one end of adjacent immovable rack bars 7b. These
immovable rack bars are each entirely disposed to extend along a
single conveyor pan section. Thus, two rack clogs 10 are secured at
spaced-apart locations to a conveyor pan section. Each immovable
rack bar 7b is secured by connecting bolts or pins 11 at its
opposite ends to the two rack holders which additionally support
the adjacent ends of movable rack bars.
[0007] Each of the clogs 10 is provided with a slot 13 located on
one-half of the holders that is nearest the joint between the
conveyor pan sections. The slots 13 in the clogs 10 extend in a
direction corresponding to the longitudinal orientation of the face
conveyor. The connecting pins 11 extend through the slots and
provide the associated movable rack bar 7a with adequate mobility
with respect to the face conveyor. The immovable rack bars 7b are
fixed with respect to the face conveyor 2 by the connecting bolts
11 which retain these rack bars by extending through bores 13'
formed in the remaining half of the holders 10. Each bore 13'
corresponds to the diameter of the pin 11.
[0008] Thus, it is common to have two rack bars 7 per line pan 9.
One rack bar 7b is fixed in the center of the line pan 9, and the
second rack bar 7a spans the joint between adjacent line pans 9.
Relative articulation between line pans during the mining process
can cause the inter-pan gap to vary considerably and this could
cause problems as the shearer drive sprocket 5 moves from the fixed
rack bar 7b to the inter-pan rack bar 7a, if the inter-pan rack bar
is firmly pinned to either adjacent pan. The common solution is for
the inter-pan rack bar pins 11 to be retained in slots 13 in the
clogs 10 rather than holes. In this manner, the error in tooth
pitch between adjacent rack bars is halved and is kinder to the
shearer sprocket 5, but causes added difficulty with pin retention,
as the pin 11 must be allowed to move along the slot 13.
[0009] More particularly, as shown in FIGS. 3, 4 and 5, the
longwall line pans 9 include a goaf side fabrication or shield
plate 14. The shield plate 14 is located adjacent the rack bar
haulage system. In order to secure the rack bar 7 to the clog 10,
the pin 11 is inserted into the clog 10 through an opening 15 in
the shield plate 14.
[0010] The clog 10 has a width corresponding to the width of the
nose-shaped extension 12, and the clog 10 defines a cavity for
engaging and providing support for the rack bar 7 by receiving the
nose-shaped extension 12, the cavity being defined by two spaced
apart bracket sidewalls 16, and end walls 17 connecting the
sidewalls 16. The clog 10 also has openings 18 through the
sidewalls 16, the pin 11 being insertable through one sidewall
opening 18 and being received in the other sidewall opening 18.
[0011] The pin has a head 19 that is larger than the opening
through the sidewall of the clog 10, so the pin 11 cannot pass
through the clog 10. In order to retain the pin 11 within the clog
10, a retainer plate 20 is dropped into the area between the head
of the pin 11 and the shield plate 14. The retainer plate 20
prevents the pin 11 from coming out of the clog 10.
[0012] Thus, as shown in FIGS. 3-5, the conventional rack bars Tare
retained in the clogs 10 by the headed pins 11 that can only be
assembled through the opening 15 in the goaf side shield plate 14.
The headed pins 11 are themselves retained by the retainer plates
20 that locate in lugs 21 welded to the goaf side shield plate 14.
The retainer plates 20 are kept in place by gravity alone, but can
be made more secure with another fastener, such as a bolt or a
spring pin.
[0013] The primary role of the clog 10 is to provide fixing points
on the line pans 7 for the semi-flexible rack bar system along
which the shearer hauls itself in order to cut material from the
seam. The nature of the system is that rack bars 7 are easily
replaced if damaged, but the clogs 10 cannot be repaired in a
hazardous environment, as the required cutting and welding is
prohibited. Hence there is a need for a strong, reliable, simple
rack-clog retention assembly.
SUMMARY
[0014] It is an object of this disclosure to provide such a strong,
reliable, simple rack-clog retention assembly.
[0015] This disclosure provides a rack bar system utilizes a forged
or cast clog with integral lugs that accept a retainer plate. The
plain rack bar pins cannot pass fully through the clog and are held
in place by a plate retainer. The retainer is simply secured by a
spring pin, or is held in place by gravity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a side elevation view of a prior art rack device
for propelled movement by a drum-type cutter machine along a mine
face.
[0017] FIG. 2 is an enlarged view of the rack device shown in FIG.
1 while supported by a face conveyor in its normal position.
[0018] FIG. 3 is an exploded perspective view of one of the line
pans shown in FIG. 1.
[0019] FIG. 4 is a partial perspective view of the connection of
one of the rack bars to a clog attached to a line pan.
[0020] FIG. 5 is a cross-sectional vertical view through the rack
bar attachment to the clog shown in FIG. 4.
[0021] FIG. 6 is a partial perspective view of an improved
mechanism for attaching a rack bar to a clog.
[0022] FIG. 7 is a perspective view of the clog and pin assembly
shown in FIG. 6.
[0023] FIG. 8 is a bottom perspective view of the back side of the
clog and pin assembly shown in FIG. 7.
[0024] FIG. 9 is a side view of the clog and pin assembly shown in
FIG. 8.
[0025] FIG. 10 is a cross-sectional view of the clog and pin
assembly shown in FIG. 9, taken along the line 10-10 in FIG. 9.
[0026] Before one embodiment of the disclosure is explained in
detail, it is to be understood that the disclosure is not limited
in its application to the details of the construction and the
arrangements of components set forth in the following description
or illustrated in the drawings. The disclosure is capable of other
embodiments and of being practiced or being carried out in various
ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. Use of "including" and
"comprising" and variations thereof as used herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Use of "consisting of" and variations
thereof as used herein is meant to encompass only the items listed
thereafter and equivalents thereof. Further, it is to be understood
that such terms as "forward", "rearward", "left", "right", "upward"
and "downward", etc., are words of convenience and are not to be
construed as limiting terms.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] This description takes as its starting point the typical
longwall conveyor fitted with rack haulage, as described above,
where a strong clog pin plate retention assembly is contained
entirely within the clog. Changing the clog position on the line
pan does not require any consequent change to the line pan.
[0028] More particularly, as illustrated in FIGS. 6-10, this
disclosure provides a rack bar haulage system 100 forming part of a
drive system for moving the mining machine along the conveyor, said
rack bar haulage system 100 including a plurality of rack bars 107,
each having spaced apart gear teeth 124 extending between cheek
sections 128 at opposite sides of the rack bar 107, and a
downwardly extending nose extension 112.
[0029] The rack bar haulage system 100 also includes a clog 110
that has a width corresponding to the width of the nose-shaped
extension 112, and the clog 110 defines a cavity 132 for engaging
and providing support for the rack bar 107 by receiving the
nose-shaped extension 112, the cavity 132 being defined by two
spaced apart bracket sidewalls 116, and end walls 117 connecting
the sidewalls 116. The clog 110 also has openings 118 and 138
through the sidewalls 116. A pin 111 is insertable through the
sidewall opening 118 and the pin 111 is received in the other
sidewall opening 138, the other sidewall opening 138 being smaller
than the end 136 of the pin 111. The other sidewall opening 138
forms a pocket that receives the end 136 of the pin 111 that does
not permit the pin 111 to pass through the other sidewall opening
138.
[0030] The clog 110 also includes means for receiving a retainer
plate 120 for retaining the pin 111 within the first sidewall
opening 118. The means for retaining the plate 120 comprises spaced
apart lugs 121 attached to the one side of one of the sidewalls
116, the lugs 121 including opposed slots 140 that receive the ends
of the retainer plate 120. The lugs 121 also include a retaining
spring pin 144 or similar for retaining the plates 120 within the
lugs 121.
[0031] In summary, the disclosed rack bar system 100 utilizes a
forged or cast clog 110 with integral lugs 121 that accept a
retainer plate 120. The plain rack bar pins 111 cannot pass fully
through the clog 110 and are held in place by a plate retainer 120.
The retainer is simply secured by a spring pin 144, or can be
merely held in place by gravity.
[0032] The retainer plate is a simple, strong device to retain clog
pins in one direction only. Note that the term plate only defines
its general shape--it is not necessarily made from rolled plate and
can be cast or forged.
[0033] The pin is plain on the prime proposal and requires no head
for retention purposes. This is cost-effective.
[0034] Various other features of this disclosure are set forth in
the following claims.
* * * * *