U.S. patent application number 11/994012 was filed with the patent office on 2009-05-21 for liner bolt and removal apparatus therefor.
This patent application is currently assigned to Dale Coray. Invention is credited to Dale CORAY.
Application Number | 20090126177 11/994012 |
Document ID | / |
Family ID | 37595007 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090126177 |
Kind Code |
A1 |
CORAY; Dale |
May 21, 2009 |
LINER BOLT AND REMOVAL APPARATUS THEREFOR
Abstract
A liner bolt (1) for securing a liner to a mill, the liner bolt
(1) comprising a head (3) and a shank (4) extending therefrom, the
shank (4) having an external thread thereon, and having a bore (5)
therein extending from its free end. A removal pin (2) is adapted
to be inserted into bore (5) when liner bolt (1) is to be removed
from the mill. Removal pin (2) is adapted to be struck by a moil
(14).
Inventors: |
CORAY; Dale; (Malahat,
British Colombia, CA) |
Correspondence
Address: |
DANIEL B. SCHEIN, PH.D., ESQ., INC.
P. O. BOX 68128
Virginia Beach
VA
23471
US
|
Assignee: |
Coray; Dale
Malahat, British Colombia
CA
|
Family ID: |
37595007 |
Appl. No.: |
11/994012 |
Filed: |
June 26, 2006 |
PCT Filed: |
June 26, 2006 |
PCT NO: |
PCT/AU06/00898 |
371 Date: |
February 14, 2008 |
Current U.S.
Class: |
29/254 ;
29/244 |
Current CPC
Class: |
B25B 27/04 20130101;
B25B 27/02 20130101; Y10T 29/49822 20150115; Y10T 29/53839
20150115; Y10T 29/53796 20150115 |
Class at
Publication: |
29/254 ;
29/244 |
International
Class: |
B23P 19/06 20060101
B23P019/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2005 |
AU |
2005903391 |
Claims
1. A liner bolt for securing a liner to a mill, said liner bolt
comprising a head and a shank extending therefrom, said shank
having an external thread thereon, characterized in that said shank
having a bore therein extending from its free end.
2. A liner bolt as claimed in claim 1, wherein in use, when said
liner bolt is to be removed from said mill a removal pin is
inserted into said bore.
3. A liner bolt as claimed in claim 2, wherein in use said removal
pin in is adapted to be struck by a moil.
4. A liner bolt as claimed in claim 3, wherein said moil is
operably mounted to a liner bolt removal tool.
5. A liner bolt as claimed in claim 4, wherein said moil is housed
within an adaptor mounted to said liner bolt removal tool, and said
adaptor is adapted to slidably engage with said pin.
6. A liner bolt as claimed in claim 1, wherein in use when said
liner bolt is to be removed from said mill a moil is adapted to be
inserted into said bore.
7. A hammer adaptor for a liner bolt removal tool, said adaptor
adapted to be fitted to said tool in such a manner to shroud said
moil, said adaptor slidably engagable with a liner bolt and a
removal pin, said liner bolt comprising a shank having a bore
therein and said removal pin adapted to be seated within said bore,
said adaptor to guide said moil into striking engagement with said
pin.
8. A hammer adaptor as claimed in claim 7, wherein said hammer
adaptor is length variable.
9. A hammer adaptor as claimed in claim 8, wherein said hammer
adaptor comprises a first tubular member spring loaded in a
telescopic arrangement with a second tubular member.
10. A removal pin in combination with a predetermined liner bolt,
said predetermined liner bolt comprising a head and a shank
extending therefrom, said shank having an external thread thereon,
and said shank having a bore therein extending from its free end,
said removal pin having a first end adapted to be inserted into
said bore of said liner bolt, and a second end adapted to be struck
by a tool when said removal pin is in engagement with said liner
bolt.
11. A liner bolt for securing a liner to a mill, said liner bolt
comprising a head and a shank extending therefrom, said shank
having an external thread thereon, said shank being of length such
that when said bolt is secured to said mill, a substantial portion
of said shank protrudes from said mill, thereby allowing a hammer
adaptor for a liner bolt removal tool to slidably engage with said
shank.
12. A liner bolt as claimed in claim 11, wherein said hammer
adaptor is length variable.
13. A liner bolt as claimed in claim 12, wherein said hammer
adaptor comprises a first tubular member spring loaded in a
telescopic arrangement with a second tubular member.
Description
TECHNICAL FIELD
[0001] The present invention relates to liner bolts and an
apparatus for removing the same from mills. In particular, the
apparatus is an adaptor that can be fitted to a liner bolt removal
tool for removal of such liner bolts.
BACKGROUND
[0002] Liner bolts are typically used to secure sacrificial liners
to the internal casing of mills used in the mining industry. The
sacrificial liners are routinely replaced during maintenance of the
mills. Typically such mills may range in size from three metres to
eleven metres in diameter and are lined with replaceable heavy
steel segments attached internally to the mill casing by through
bolting using liner bolts. The liner bolts typically have a
diameter of up to about 50 mm (2 inches).
[0003] In such applications, the bolts become corroded and
clearances between bolts and holes become compacted with ore fines.
This results in difficult bolt removal at liner removal time. As a
result the many liner bolts that are utilised to attach the liners
to the mill shell are often required to be freed manually by the
use of large sledge-hammers. This is a difficult and time-consuming
task that may result in injury to the workers.
[0004] While it is well known to use percussive devices such as
jack-hammers and hydraulically powered hammers to provide
repetitive impacts for many applications, they are not able to be
manually guided into alignment with wall mounted bolts and other
components. The applications of jack hammers are limited as the
hammering effect produced by an electrically or pneumatically
operated jack hammer does not provide the impact as would be
provided by a sledge hammer, for example.
[0005] In known hammering devices capable of delivering such
impacts, a high reaction force is produced which necessitates that
such devices be carried by articulating machines or be rigidly
attached to some support structure. This reduces their versatility
and makes them unsuitable for many applications. Furthermore, it is
difficult to quickly and accurately align such devices with the
shank of a bolt or the like for effecting ready removal
thereof.
[0006] International publication WO97/26116 (Russell Mineral
Equipment Pty Ltd) describes a hydraulic linerbolt removal tool.
The hydraulic tool essentially comprises a housing having a moil
mounted at the forward end and a hydraulic piston assembly
reciprocally moveable along the hammer axis between a striking
position at which the piston assembly strikes the impact delivery
member and a retracted position remote from the impact delivery
member. A firing means is provided for hydraulically firing the
piston assembly from its retracted position to its striking
position under the control of actuating means. A reactive body
assembly is moveable in the direction of the hammer axis by driving
means towards the impact delivery member prior to operation of the
firing means whereby the reactive body assembly may be energised by
movement and subsequently decelerated to substantially absorb the
reaction generated by firing the piston assembly. Recoil is thus
reduced whereby the apparatus may be operated by hand with the
apparatus being suspended about its centre of gravity at the work
site.
[0007] U.S. Pat. No. 6,904,980 (Rubie) describes a pneumatic liner
bolt removal tool that is operable from a conventional compressed
air supply.
[0008] A disadvantage associated with using such prior art liner
bolt removal tools to remove conventional liner bolts, is that it
is necessary for the operator of the removal tool be assisted by a
workman who helps align the moil of the removal tool with the liner
bolt. This is because even though the removal tools are suspended,
their size and weight makes them difficult to handle and they
obstruct the operator's view of the work area. The workman
assisting the operator typically utilizes a handheld moil guide as
shown in FIG. 1 of this specification. This places the workman
assisting the operator of the liner bolt removal tool at risk of
injury, due to his proximity to the working end of the tool as it
is aligned with the liner bolt.
[0009] Another disadvantage of removing liner bolts using these
liner bolt removal tools is the damage caused to the mill casing in
the area around the bolt hole, as a result of misalignment.
[0010] The present invention seeks to overcome at least some of the
abovementioned disadvantages.
SUMMARY OF INVENTION
[0011] According to a first aspect the present invention consists
of a liner bolt for securing a liner to a mill, said liner bolt
comprising a head and a shank extending therefrom, said shank
having an external thread thereon, characterized in that said shank
having a bore therein extending from its free end.
[0012] Preferably in use, when said liner bolt is to be removed
from said mill in a first embodiment, a removal pin is inserted
into said bore.
[0013] Preferably in use, said removal pin in is adapted to be
struck by a moil.
[0014] Preferably, said moil is operably mounted to a liner bolt
removal tool.
[0015] Preferably, said moil is housed within an adaptor mounted to
said liner bolt removal tool, and said adaptor is adapted to
slidably engage with said pin.
[0016] Preferably, when said liner bolt is to be removed from said
mill in a second embodiment, a moil is adapted to be inserted into
said bore.
[0017] According to a second aspect the present invention consists
of a hammer adaptor for a liner bolt removal tool, said adaptor
adapted to be fitted to said tool in such a manner to shroud said
moil, said adaptor slidably engagable with a liner bolt and a
removal pin, said liner bolt comprising a shank having a bore
therein and said removal pin adapted to be seated within said bore,
said adaptor to guide said moil into striking engagement with said
pin.
[0018] Preferably, said hammer adaptor is length variable.
[0019] Preferably, said hammer adaptor comprises a first tubular
member spring loaded in a telescopic arrangement with a second
tubular member.
[0020] According to a third aspect the present invention consists
of a removal pin in combination with a predetermined liner bolt,
said predetermined liner bolt comprising a head and a shank
extending therefrom, said shank having an external thread thereon,
and said shank having a bore therein extending from its free end,
said removal pin having a first end adapted to be inserted into
said bore of said liner bolt, and a second end adapted to be struck
by a tool when said removal pin is in engagement with said liner
bolt.
[0021] According to a fourth aspect the present invention consists
of a liner bolt for securing a liner to a mill, said liner bolt
comprising a head and a shank extending therefrom, said shank
having an external thread thereon, said shank being of length such
that when said bolt is secured to said mill, a substantial portion
of said shank protrudes from said mill, thereby allowing a hammer
adaptor for a liner bolt removal tool to slidably engage with said
shank
[0022] Preferably, said hammer adaptor is length variable.
[0023] Preferably, said hammer adaptor comprises a first tubular
member spring loaded in a telescopic arrangement with a second
tubular member.
BRIEF DESCRIPTION OF DRAWINGS
[0024] In order that this invention may be more readily understood
and put into practical effect, reference will now be made to the
accompanying drawings which illustrate a typical embodiment of the
invention and wherein:
[0025] FIG. 1 is a partial perspective view of prior art liner bolt
removal tool being used with a prior art hand-held guide to remove
a prior art liner bolt.
[0026] FIG. 2 is a perspective view of a liner bolt and a removal
pin therefor in accordance with a first embodiment of the present
invention;
[0027] FIG. 3 is a perspective view of the liner bolt of FIG. 2,
with the removal pin engaged therewith.
[0028] FIG. 4 is a partial perspective view of a liner bolt removal
tool fitted with an adaptor for removal of a liner bolt of the type
shown in FIG. 1.
[0029] FIG. 5 is a partial cross-sectional view of the liner bolt
removal tool and adaptor shown in FIG. 4 set up to remove the liner
bolt.
[0030] FIG. 6 is a partial cross-sectional view of the liner bolt
removal tool and adaptor shown in FIG. 4 as the liner bolt is being
removed.
[0031] FIG. 7 is a perspective view of the adaptor shown in FIG.
4.
[0032] FIG. 8 is a cut-away perspective view of the adaptor shown
in FIG. 7.
[0033] FIG. 9 is a partial cross-sectional view of an alternative
embodiment of a moil set up to remove a liner bolt of the type
shown in FIG. 1.
[0034] FIG. 10 is a partial cross-sectional view of a liner bolt in
accordance with a second embodiment of the present invention.
MODE OF CARRYING OUT INVENTION
[0035] FIG. 1 is a prior art liner bolt removal tool 10 that
utilises a hand-held moil guide 30 to remove a conventional liner
bolt from a liner secured to a mill casing.
[0036] FIGS. 2 and 3 depict a liner bolt 1 and a removal pin
(drifter) 2 in accordance with a first embodiment of the present
invention. Liner bolt 1 is adapted for securing a sacrificial liner
to the internal casing of a mill used in the mining industry.
[0037] Liner bolt 1 comprises an oval shaped head 3 and a shank 4
extending therefrom. Shank 4 is preferably threaded in a
conventional manner to allow a fastening nut (not shown) to engage
therewith. Liner bolt 1 also comprises a bore 5 that extends into
shank 4 a short distance from its free end 6. Liner bolt 1 is made
of a similar material used for conventional liner bolts.
[0038] Removal pin 2 comprises a first cylindrical end 7, a central
portion 8 and a second cylindrical end 9. The first cylindrical end
7 has a diameter smaller than the second cylindrical end 9. Central
portion 8 has a diameter substantially greater than both first and
second ends 7,9. Central portion 8 also has a flat face facing the
direction to which the first cylindrical end 7 extends. Pin 2 is
preferably made of a substantially hardened material and is
reusable.
[0039] In use, liner bolt 1 secures a liner to a mill casing in a
conventional manner, with the head 3 of liner bolt 1 located
internally and shank 4 projecting externally of the mill casing. In
order to remove the liner bolt 4, the second cylindrical end 7 of
pin 2 is fully inserted into bore 5 such that the flat face of
central portion 8 abuts against the free end 6 of shank 4. In order
to remove the liner bolt 1, the second cylindrical end 9 of pin 8
is preferably struck by the moil of a hammer.
[0040] The liner bolt 1 may be made in sizes to replace
conventional liner bolts. In one particular size, the liner bolt 1
may have a shank 4 with a diameter of about 45 mm, and an overall
length of about 300-350 mm. This size bolt may have a bore 5 of
about 25 mm diameter and about 75 mm in length.
[0041] FIGS. 4, 5 and 6 depict a conventional liner bolt removal
tool 10 fitted with a hammer adaptor 11 used to remove liner bolt 1
from a liner 12 and mill casing 13, via removal pin 2. Adaptor 11,
which has a spring-loaded telescopic arrangement, is fitted to tool
10 with moil 14 extending therethrough.
[0042] As can be seen in FIG. 5, pin 2 is inserted into bore 5 of
liner bolt 1. The free end of adaptor 11 is slid onto the shank 4
of liner bolt 1, such that the fore end of moil 14 of tool 10 is in
contact with second cylindrical end 9 of pin 2. Once the adaptor 11
is in place, the tool 11 does not require additional operator
guidance. In use, tool 10 is activated by the operator (not shown),
and moil 14 strikes pin 2, which in turn urges both pin 2 and liner
bolt 1 from liner 12 and mill casing 13. Also, the pin 2 can be
recovered and re-used.
[0043] FIGS. 7 and 8 depict hammer adaptor 11. The hammer adaptor
11 comprises a first tubular member 17 spring loaded by spring 18
in a telescopic arrangement with a second tubular member 19. A
flange 20 having apertures 21, extends from an end of second
tubular member 19. The flange 20 allows adaptor 11 to be connected
to a conventional liner bolt removal tool 10. Second tubular member
19 is fixed relative to tool 10, however during operation, as the
tool 10 is fired, the overall length of adaptor 11 is variable as
first tubular member 17 slides relative to the second tubular
member 19.
[0044] In an alternative embodiment as shown in FIG. 9,
particularly suited to where it is difficult to use a pin 2, a
special purpose moil 14a may have a pin end 15 adapted to engage
directly with bore 5 of liner bolt 1.
[0045] FIG. 10 depicts a liner bolt 101 in accordance with a second
embodiment of the present invention. Liner bolt 101, is in effect
as if the liner bolt 1 and pin 2 as shown in FIG. 5 are integrated
together to form bolt 101 having a shank 104.
[0046] This shank 104 has an external thread thereon, thereby
allowing it to be secured to mill casing 13 in a like manner to
bolt 1 shown in FIG. 5. However, in this embodiment the free end of
shank 104 extends a substantial length externally of the mill,
thereby allowing the hammer adaptor 11 to slidably engage
therewith. The hammer adaptor 11 being fitted to a tool 10 carrying
a moil 14, similar to that shown in the first embodiment.
[0047] Removal of the liner bolts 1 as described in the
abovementioned embodiments not only minimises the risk of injury to
workers, but may result in the actual knock out times being reduced
by 40-60%, which is a considerable saving of downtime. Another
advantage of liner bolt 1 and removal pin 2 is that their use
significantly reduces risk of damaging the area around the bolt
hole.
[0048] The term "comprising" (and its grammatical variations) as
used herein is used in the inclusive sense of "having" or
"including" and not in the exclusive sense of "consisting only
of".
* * * * *