U.S. patent application number 11/661117 was filed with the patent office on 2008-04-24 for cutting tool holding apparatus and method of use.
This patent application is currently assigned to GROUND ASSAULT TOOLS PTY LTD. Invention is credited to John Michael Willoughby.
Application Number | 20080093912 11/661117 |
Document ID | / |
Family ID | 37396069 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080093912 |
Kind Code |
A1 |
Willoughby; John Michael |
April 24, 2008 |
Cutting Tool Holding Apparatus And Method Of Use
Abstract
A cutting tool holding apparatus (10), including in combination
a cutting tool holder (14); a retainer (18) adapted to be
positioned adjacent to the tool holder (14), the retainer including
an aperture (18c), a base (16) including an aperture (16c) linked
to the retainer aperture (18c), the base (16) adapted to support
the holder (14) and the retainer (18), and a fastener (20) adapted
to be inserted through the linked apertures, wherein securing the
fastener in the linked apertures wedges the holder, retainer and
base together and wherein at least two components of the tool
holder, retainer and base contact via mating curved faces.
Inventors: |
Willoughby; John Michael;
(Belmont, AU) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
GROUND ASSAULT TOOLS PTY
LTD
233 LAVARACK AVENUE
EAGLE FARM
AU
4009
|
Family ID: |
37396069 |
Appl. No.: |
11/661117 |
Filed: |
January 6, 2006 |
PCT Filed: |
January 6, 2006 |
PCT NO: |
PCT/AU06/00006 |
371 Date: |
February 26, 2007 |
Current U.S.
Class: |
299/107 ;
299/10 |
Current CPC
Class: |
E21C 35/19 20130101;
E21C 35/191 20200501 |
Class at
Publication: |
299/107 ;
299/010 |
International
Class: |
E21C 35/193 20060101
E21C035/193 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 2005 |
AU |
2005902428 |
Claims
1-35. (canceled)
36. A cutting tool holding apparatus, including: a cutting tool
holder; a retainer adapted to be positioned adjacent to the tool
holder, the retainer including an aperture, a base including an
aperture linked to the retainer aperture, the base adapted to
support the holder and the retainer, and a fastener adapted to be
inserted through the linked apertures, wherein securing the
fastener in the linked apertures wedges the holder, retainer and
base together and wherein at least two components of the tool
holder, retainer and base contact via complementary mating
faces.
37. A cutting tool holding apparatus as claimed in claim 36,
wherein the secured fastener provides a wedging force between the
three components of the holder, retainer and base which enables a
pre-loading on the complementary mating faces that assists in
self-alignment of the three components irrespective of impacting
movement forces.
38. A cutting tool holding apparatus as claimed in claim 36 wherein
the complementary mating faces are located on the holder and
base.
39. A cutting tool holding apparatus as claimed in claim 38 wherein
the complementary mating faces are curved.
40. A cutting tool holding apparatus as claimed in claim 39,
wherein, the curved face of the base is a partial spherical ball
and the mating curved face on the holder is a matching partial
spherical indent.
41. A cutting tool holding apparatus as claimed in claim 40,
wherein, the centre of the partial spherical ball is approximate to
the radius path between tip of the cutting tool and centre of the
drum, wheel, conveyor or other rotating apparatus.
42. A cutting tool holding apparatus as claimed in claim 36,
wherein, the base and retainer and/or the retainer and holder also
include mating curved faces.
43. A cutting tool holding apparatus as claimed in claim 42,
wherein, there are additional contact points between the three
components when securely fastened.
44. A cutting tool as claimed in claim 36, wherein, the tool holder
includes two curved beveled legs straddling each side of the
partial spherical ball of the base.
45. A cutting tool holding apparatus as claimed in claim 36,
wherein, the base includes two curved partial spherical saddles
each side of the partial spherical ball of the base.
46. A cutting tool holding apparatus as claimed in claim 36,
wherein, the tool holder has one or more additional curved face/s
mating to a curved face/s on the retainer, wherein the curved
matching faces further assist in self aligning of the three major
components of the tool holder apparatus namely, the tool holder,
retainer and base.
47. A cuffing tool holding apparatus as claimed in claim 46,
wherein, additional curved faces on the base match opposing curved
faces of the retainer.
48. A cutting tool holding apparatus as claimed in claim 36,
wherein, all of the mating curved faces of the components assist in
self alignment of the cutting tool holder despite rotational
movement stresses.
49. A cutting tool holding apparatus as claimed in claim 36
wherein, the securing fastener asserts an initial force aligning
the tool holder, retainer and base.
50. A cutting tool holding apparatus as claimed in claim 49,
wherein, the securing fastener is a bolt utilised with a washer
having a partially spherical underside, wherein the underside
assists in aligning the securing bolt and assists in maintaining a
large contact surface between the mating faces of the washer and
retainer.
51. A cutting tool holding apparatus as claimed in claim 36,
wherein, the cutting tool holding apparatus includes a replaceable
cuffing tool which may be a tooth or a bit depending on the type of
ground surface that needs to be excavated.
52. A cuffing tool holding apparatus as claimed in claim 36,
wherein, the base of the cutting tool holder assembly has a
contacting face that matches the surface of the drum, wheel, or
conveyor on which the tool holder apparatus is mounted.
53. A cutting tool holding apparatus as claimed in claim 52,
wherein, the cutting tool holding apparatus is attached to the
surface of the drum, wheel, or conveyor or the like by a weld.
54. A cuffing tool holding apparatus as claimed in claim 52,
wherein the base is manufactured as an integral part of the drum,
wheel or conveyor.
55. A cuffing tool holding apparatus as claimed in claim 36,
wherein, the components of the cutting tool holding apparatus,
being the tool holder, retainer and base, all have complementary.
mating faces that enable a matching fit so that the impact from the
ground is passed from the cutting tool to each mating face to the
drum or other rotation means which substantially eliminates any
movement between the components.
56. A cutting tool holding apparatus as claim in claim 54, wherein,
all mating faces are smooth and blemish free.
57. A cutting tool holding apparatus as claimed in claim 55,
wherein, the mating faces of the components do not substantially
cause misalignment, even if there is some dirt or grit between the
components.
58. A cutting tool holding apparatus as claimed in claim 36
attachable to a rotatable ground engaging drum, wheel or conveyor,
said cutting tool holding apparatus including one or more
replaceable cuffing tools.
59. A cutting tool holding apparatus, including: a cuffing tool
holder, a retainer adapted to be positioned adjacent to the tool
holder, said retainer including an aperture, a base including an
aperture linked to the retainer aperture, said base adapted to
support the holder and the retainer, and a fastener adapted to be
inserted through the linked apertures, wherein securing the
fastener in the linked apertures wedges the holder, retainer and
base together, wherein at least two or more components of the tool
holder, retainer and base contact via mating curved faces, wherein
there are at least two paired mating curved faces between two or
more of the components, and wherein the two pairs of mating curved
faces radii have the same centre point.
60. A cuffing tool holding apparatus as claimed in claim 59,
wherein, there are paired sets of mating curved faces between the
tool holder and the base and retainer and base.
61. A cuffing tool holding apparatus as claimed in claim 59,
wherein there are complementary sets of mating curved faces between
the retainer and the tool holder.
62. A cutting tool holding apparatus as claimed in claim 59, having
a sacrificial wear component that can be replaced.
63. A cutting tool holding apparatus as claimed in claim 62,
whereby the sacrificial wear component has legs that fit into slots
or ribs in the base.
64. A cutting tool holding apparatus as claimed in claim 62,
wherein, the sacrificial wear component is cast.
65. A cutting tool holding apparatus as claimed in claim 63,
wherein when the tooth holder is secured into position the
sacrificial wear component cannot be removed from the slots or ribs
by the obstruction of the tooth holder.
66. A cutting tool holding apparatus as claimed in claim 62,
whereby, the sacrificial wear component is replaced by removal of
the retainer and tooth holder.
67. A cutting tool holding apparatus as claimed in claim 62,
wherein, the wear component is preferably of a high alloy steel or
equivalent material.
68. A cutting tool holding apparatus as claimed in claim 59,
wherein, the tooth holder has a slot in the rear of the tooth
holder which allows for the insertion of a tooth punch or
drift.
69. A cutting tool holding apparatus as claimed in claim 68,
wherein, the punch or drift is used as a lever to release the
retainer from a tightened position by tapping the punch with a
hammer to apply an impact force sufficient to release the taper
lock between the components.
70. A method of excavating a ground surface utilizing a road,
mining or trenching machine having plurality of cutting tool
holding apparatus as claimed in claim 59.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an apparatus for holding a cutting
tool and methods of use thereof. In particular, the invention
relates to apparatus for holding a cutting tool holder that is
utilised on a ground engaging drum or wheel that excavates into the
ground surface.
BACKGROUND OF THE INVENTION
[0002] There are a variety of road and mining machines that include
a plurality of holders for securing cutting bits or teeth that
assist in cutting into earth, asphalt, concrete or other hardened
surfaces. Typically, these machines have a rotating drum, wheel or
conveyor having a plurality of tool holders secured, generally by
welding, cutting tools which are utilised to bite, cut, mill or
trench into the hardened surface via the rotation of the drum,
wheel or conveyor during operation.
[0003] It is inevitable that due to the severe environment
accidental damage of known cutting tool holders and the cutting
tools can occur before its normal expected lifetime. As such, there
are extensive costs in replacing the cutting holders and the
secured tool that cut into the hardened surface due to wear and
tear as work is conducted over a high number of revolutions. In
addition, the cutting tool holder may even detach completely and is
not recoverable.
[0004] In current known ground engaging machinery, there can be
about 80 cuffing tool holders positioned on a metre wide drum or
other rotating means. The drum rotates at approximately 100
revolutions per minute. As such, the cutting tool holders typically
experience several million impacts with a typical force of three
tonnes on each impact. Accordingly, there can be severe wear and
tear on each cutting tool holder during its operational life.
[0005] Existing methods include welding a tool holder onto a
rotating drum, wheel, conveyor or other rotating mechanism. Though
this may appear to be initially cost efficient in setting up costs,
there are also continuous applied stresses and abrasion which often
quickly damages the cutting tool holder. A severe impact may
fracture the weld and break off the tool holder. The requirement to
replace the tool holder may be difficult when on site as it lacks
practicality and can be time consuming and expensive. The cost in
loss of production and replacement time proves to be even more
expensive.
[0006] Other techniques in the industry require the attachment of
the cutting tools via tapered locks. A problem associated with this
technique is the continuous forces applied to the cutting tool can
deform the tapered cavity. The force applied to the cutting tool
drives the cutting tool into their respective holders, especially
into the shoulders of the holder. Hence, withdrawing a cutting tool
from a deformed damaged taper can be difficult. In addition,
replacing a cutting tool into the damaged cavity can leave the
cutting tool loose and/or misaligned.
[0007] A further technique utilises cutting tool holders having a
rectangular post which is secured in a rectangular cavity employing
a high tensile bolt or screw enabling attachment to a rotating drum
or the like. During the life of the holder the bolt can come loose.
This is due to the mating faces between the cutting tool holder and
the tool holder base becoming worn making it difficult to keep the
bolt tight. Periodical tensioning of the bolt is recommended, but
is often impractical given the number of cutting tool holders and
the environment it works in. The task of retensioning is costly and
time consuming.
[0008] In addition, due to the wear and tear the bolt may become
loose prematurely and the tool holder can become detached and is
not recoverable. Replacement of the tool holder can be expensive
due to time out and the costs for replacement.
[0009] It would be advantageous to at least substantially
ameliorate the disadvantages and shortcomings of the prior art or
to at least provide the public with a useful alternative. For
example, it would be advantageous to provide a cutting tool holding
apparatus that may assist in transferring the stress on the cutting
tool when in use and to potentially avoid the required of
periodically retensioning the cutting tool holder.
SUMMARY OF THE INVENTION
[0010] This invention resides broadly in a cutting tool holding
apparatus, including:
[0011] a cutting tool holder;
[0012] a retainer adapted to be positioned adjacent to the tool
holder, said retainer including an aperture,
[0013] a base including an aperture linked to the retainer
aperture, said base adapted to support the tool holder and the
retainer, and
[0014] a fastener adapted to be inserted through the linked
apertures,
[0015] wherein securing the fastener in the linked apertures wedges
the holder, retainer and base together and wherein at least two
components of the tool holder, retainer and base contact via
complementary mating faces.
[0016] Preferably the secured fastener provides a wedging force
between the three components of the holder, retainer and base which
enables a pre-loading on the complementary mating faces that
assists in self-alignment of the three components irrespective of
impacting movement forces.
[0017] In one preferred embodiment, the complementary mating faces
are located on the holder and base. Preferably, the complementary
mating faces are curved. More preferably the curved face of the
base is a partial spherical ball and the mating curved face on the
holder is a matching partial spherical indent. In a further
preferred embodiment, the centre of the partial spherical ball is
approximate to the radius path between tip of the cutting tool and
centre of the drum, wheel, conveyor or other rotating apparatus.
This may minimize the movement of the cutting tool tip from
misalignment. For example, if the cuffing tool holder happens to
rotate slightly around the base in such a manner as to alter the
angle of attack, the cutting tool still cuts at close to its
designed depth.
[0018] In other preferred embodiments, the base and retainer and/or
the retainer and holder also including mating curved faces. There
may be additional contact points between the three components when
securely fastened. For example, the tool holder legs may include
two curved beveled legs straddling each side of the partial
spherical ball of the base. The base may also include two curved
saddles each side of the partial spherical ball of the base that
have faces that match to the curved beveled legs of the tool holder
to assist in aligning the tool holder with the base.
[0019] In another embodiment, the tool holder may have one or more
additional curved face/s mating to a curved face/s on the retainer,
wherein the curved matching faces further assist in self aligning
of the three major components of the tool holder apparatus, i.e.
the tool holder, retainer and base. In a further embodiment,
additional curved face/s on the base may match opposing curved
faces of the retainer.
[0020] All of the mating curved faces of the three components
assist in self alignment of the cutting tool holder despite
rotational movement stresses.
[0021] Suitably, the securing fastener asserts an initial force
aligning the tool holder, retainer and base. Preferably, the
securing fastener is a bolt utilised with a washer having a
partially spherical underside, wherein the underside assists in
aligning the securing bolt and maintaining full contact between
mating faces of the washer and the retainer. Of course the fastener
is not limited to a bolt and could be a screw, rivet, or other
attachment means. The cutting tool holding apparatus may include a
replaceable cutting tool which may be a tooth or a bit depending on
the type of ground surface that needs to be excavated.
[0022] In other known methods, when the faces are subjected to
forces through repeated cyclical loads the tool holder generally
fails due to excessive forces. However, the present invention with
mating curved faces secured by the fastener preloads the mating
faces to an extent which is surprising and unexpected as the mating
faces do not substantially move essentially keeping the cutting
tool self-aligned.
[0023] Suitably, the base of the cutting tool holder assembly has a
contacting face that matches the surface of the drum, wheel,
conveyor or the like. Preferably, the cutting tool holding
apparatus is attached to the surface of the drum, wheel, conveyor
or the like by a weld. However, it is to be appreciated that other
types of fastening connections may be employed. The base could be
manufactured as an integral part of the drum, wheel or conveyor or
other rotating means.
[0024] The cutting tool holding apparatus is part of a machine that
enables rotation of the drum that cuts, grinds or bites into a
ground surface. The components of the cutting tool holding
apparatus, being the tool holder, retainer and base, all suitably
have complementary mating faces that enable a matching fit so that
the impact from the ground is passed from the cutting tool to each
mating face to the drum or other rotation means which substantially
eliminates any movement between the components. Further if there is
any misalignment of the tool holder, the combination of the mating
faces still maintains the cutting tool in alignment. Suitably all
mating faces are smooth and blemish free.
[0025] If the cutting tool holding apparatus does not need to be
constantly replaced, then it is a simple matter to replace the
tooth or bit when it becomes worn. In addition, replacement of the
cutting tool holding apparatus generally occurs in a "dirty"
environment being on the road or in a mining situation. Any dirt in
past tool holders causes problems, however the present arrangement
of the mating faces of the three components of the present
invention do not substantially cause misalignment, even if there is
some dirt or grit.
[0026] In another aspect this invention resides in a method of
excavating a ground surface utilizing a road or mining machine
having a plurality of cutting tool holding apparatus as described
above attachable to a rotatable ground engaging drum, wheel or
conveyor, said cutting tool holding apparatus including one or more
replaceable cuffing tools.
[0027] As discussed above, the tool holder may include two curved
beveled legs which are locatable each side of the partial spherical
ball positioned centrally on one end of the base with saddles
matching the two curved beveled legs. It is preferred that the
centre of the radius of the curved legs and the centre of radius of
the partial spherical indent are the same. The radii of two curved
faces may be different in length but the centre point is the
same.
[0028] Further, there may be two matching curved faces between the
retainer and the base wherein the centre point of the two matching
curves are the same despite differing lengths of the radii. The
advantage of having the same centre point for a set of matching
curved faces is that the two relative components have the ability
to slide relative to each. This enables the ability to manage any
side loading by providing a very substantial mechanical advantage
enabling self-alignment of the components. So even if there is a
side loading applied to the cutting tool tip, alignment is
maintained.
[0029] In a still further aspect, this invention resides broadly in
a cutting tool holding apparatus, including:
[0030] a cutting tool holder,
[0031] a retainer adapted to be positioned adjacent to the tool
holder, said retainer including an aperture,
[0032] a base including an aperture linked to the retainer
aperture, said base adapted to support the holder and the retainer,
and
[0033] a fastener adapted to be inserted through the linked
apertures,
[0034] wherein securing the fastener in the linked apertures wedges
the holder, retainer and base together,
[0035] wherein at least two or more components of the tool holder,
retainer and base contact via mating curved faces,
[0036] wherein there are at least two paired mating curved faces
between the two or more of the components, and
[0037] wherein, the radii of the two pairs of mating curved faces
have the same centre point.
[0038] Essentially the mechanical advantages are obtained by having
the centre point of the radius which enables a pivoting effect that
is favoured in the direction of the curve, rather than by lateral
movements against the curve. As such, the components have the
mechanical ability to self align no matter what the direction the
forces or stress.
[0039] Preferably, there are complementary sets of mating curved
faces between the tool holder and the base and retainer and base.
There may also be paired sets of mating curved faces between the
retainer and the tool holder.
[0040] As in the present invention, with high productivity, high
horsepower machine applications wear is likely to be a problem on
the leading front face of the base. Since it is intended that this
component is not to be required to be replaced during the expected
life of the road or mining machine, it is advantageous to have a
sacrificial wear plate in front of the leading face that can easily
be replaced if necessary.
[0041] Preferably, the sacrificial wear component has two legs that
fit into two slots or ribs in the base when fitted. Wear will occur
on the face and at some stage it will be necessary to replace only
the component. Since wear rates of cutting tool holding apparatus
are not consistent across the drums in such machines some may need
replacing before others are worn out. To make a base with
sufficient material as a sacrificial plate would add substantially
to the cost. The base must be made of such a material as to be able
to be welded to the drum and therefore a large amount of material
would be required over the life of the machine. Furthermore, a
small cast sacrificial wear component with no machining or welding
can be made very hard and highly abrasive resistant at low cost.
Preferably, when the tooth holder is secured into position the
sacrificial wear component cannot be removed from the slots or ribs
by the obstruction of the tooth holder.
[0042] It is envisaged that fine material from the cutting action
of the teeth will impact and build up between the sacrificial wear
component and the tooth holder and base and secure the sacrificial
wear component in position so as no wear occurs in the slots or
ribs on the base or the front face of the tooth holder. Suitably,
the sacrificial wear component may be replaced by removal of the
retainer and tooth holder. The wear component is preferably of a
high alloy steel or equivalent material.
[0043] Preferably, the tooth holder has a slot in the rear of the
tooth holder which allows for the insertion of a tooth punch or
drift whereby the punch can be used as a lever to release the
retainer from a tightened position by tapping the punch with a
hammer to apply an impact sufficient to release the taper lock
between the three components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] 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 preferred embodiment of
the invention and wherein:
[0045] FIG. 1 illustrates an exploded view of a cutting tool holder
apparatus in accordance to the invention as described,
[0046] FIG. 2 illustrates a side view of the cutting tool holder
apparatus when assembled,
[0047] FIG. 3 illustrated a rear perspective view of the cutting
tool holder apparatus when assembled,
[0048] FIG. 4 illustrates of top view of the cutting tool holder
apparatus when assembled,
[0049] FIG. 5 illustrates a side view of the cutting tool holder
apparatus when assembled,
[0050] FIG. 6 illustrates a rear view of the cutting tool holder
apparatus when assembled,
[0051] FIG. 7 illustrates a side cross sectional view of the
cutting tool holder apparatus when assembled.
[0052] FIG. 8 illustrates rotated perspective views of a base,
[0053] FIG. 9 illustrates rotated perspective views of the
retainer, and
[0054] FIG. 10 illustrates rotated perspective views of a tool
holder.
[0055] FIG. 11 illustrates a preferred sacrificial wear component
according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0056] In addition terms such as "front", "back", "base", "top",
"side", "bottom", "end", "rear", "underside" etc. refer to the
orientation or configuration of a cutting tool holding apparatus
when used according to the illustrations and to assist in
indicating points of reference when viewing the accompanying
figures. It is to be understood that these terms do not limit the
present invention to any specific orientation or configuration of
the invention.
[0057] In the specification the terms "comprising" and "containing"
shall be understood to have a broad meaning similar to the term
"including" and will be understood to imply the inclusion of a
stated integer or step or group of integers or steps but not the
exclusion of any other integer or step or group of integers or
steps. This definition also applies to variations on the terms
"comprising" and "containing" such as "comprise", "comprises",
"contain" and "contains".
[0058] FIGS. 1-11 illustrate one embodiment of a cutting tool
holding apparatus 10 of the invention as described. Though not
illustrated, an embodiment of the invention could include a
plurality of cuffing tool holder apparatuses 10 being affixed to a
rotating drum, wheel, conveyor or the like and used in excavation
machinery.
[0059] The cutting tool holder apparatus 10 includes a cutting tool
holder 14, base 16 and retainer 18 that have interconnecting curved
faces linking the apparatus together via a fastener 20, such as a
bolt. The cutting tool holder 14 illustrated in FIG. 10 includes a
cuffing tool 12 which is inserted into the holder 14. As best
illustrated in FIG. 1, a preferred embodiment of the cutting tool
12 has a tungsten carbide tip 12a which is used as the abrasive
tool for excavating into a ground surface. The cutting tool 12
includes a housing 12b upon where the tip is mounted and a collar
12c, wherein the cuffing tool 12 can engage the cutting tool holder
14 using the post 12d and spring clip retainer via a matching
aperture 14e in the tool holder 14.
[0060] The tool holder 14 includes a spherical indent 14a and an
aperture 14e to receive the cutting tool 12. The base 16 as best
show in FIG. 8 includes a partial spherical ball section 16a that
matches the spherical indent 14a of the tool holder 14. Further,
the base 16 includes a saddle region 16d adjacent to the partial
spherical ball section 16a for enabling a straddling pair of legs
14b of the tool holder 14 to straddle the partial spherical ball
section 16a. The base 16 also has a curved bevelled rear section
16b, a beveled section adjacent 16e to a securing bolt aperture 16c
for engaging a securing bolt 20. It should be noted that the curved
beveled sections 16b and 16e have the same radii centre point.
[0061] As illustrated in FIG. 9, the retainer 18 includes a linking
aperture 18c to the base aperture 16c for receiving the securing
bolt 20 and washer 22, a curved bevelled underside 18a and 18d, and
beveled rear 18b and 18e.
[0062] The assembled tool cutting holder apparatus is depicted in
FIGS. 2 to 7, wherein the tool holder 14 resides between the
retainer 18 and the base 16. When the tool holder 14 is fitted onto
the base 16, there is contact between the two components on the
spherical ball 16a and spherical indent 14a; and between the two
legs 14b and the spherical saddle 16d.
[0063] The partial spherical ball 16a and the spherical indent 14a,
allows slight pivoting of the tool holder 14 upon the central
position upon the base 16, but any side loading enables
self-alignment due to this arrangement. The unique curved beveled
shape of the two legs 14b of the holder mates with the curved
saddle 16d of the base. In addition, the curved beveled legs 14b
are angled slightly inward. This unique configuration allows any
lateral forces experienced by the assembly to self-align.
[0064] The retainer 18 is positioned between the tool holder 14 and
the base 16 being interconnected by matching curved faces. The
retainer 18 includes an aperture 18c for receiving a high tensile
bolt 20 which provides the load upon the assembly. In an embodiment
of the invention the bolt is accompanied by a washer 22 having a
partial spherical underside that fits within a recess in the
aperture.
[0065] The retainer 18 includes a curved beveled underside 18a
which engage the two respective curved faces of the two legs 14d of
the tool holder 14. The retainer 18 also has a curved beveled
underside 18d which engages against the curved beveled underside
14f of the tool holder 14 adjacent to the aperture 14e. It should
be noted that the curved surfaces of 18a and 18d have the same
radius centre point even though the radii have different
lengths.
[0066] The curved beveled underside 18a and 18d are slightly angled
inwards, while the two legs of the tool holder are angled slightly
outward. This configuration allows the two components to interlock;
hence any lateral forces experienced by the assembly which would
allow the retainer and tool holder to slide into position, hence
re-aligning during assembly.
[0067] In addition, the rear end 18b, and 18e of the retainer 18
includes a beveled face which mates with the curved beveled rear
end of the base 16b and 16e. The centre point of the radii is the
same for the faces 18b and 18e. As stated previously, any lateral
forces applied upon the assembly will not misalign the assembly
since the curved beveled shaped faces will allow the components to
slide into position upon tensioning bolt 20 ensuring all components
are self aligned.
[0068] Therefore in operation, the apparatus 10 may experience
forces anywhere in between perpendicular and lateral. In regards to
the perpendicular forces, the general curved shapes of the
components allow the cuffing tool holding apparatus as a whole to
absorb forces generated by the tool, in particular the tensioning
of the bolt 20 that preloads the mating faces of the three
components 14, 16 and 18 to eliminate any sliding motion between
mating faces under normal loads. Though it would be imagined that
the securing bolt 20 absorb the majority of the perpendicular
forces, this is not the case. The unique configuration allows each
of the components to absorb the impact. While the securing bolt 20
enables the three components to be wedged together and the unique
feature of the matching curved faces actually enable the tool
holder apparatus 10 to self-align despite any stress.
[0069] An additional design feature includes the centre of the
spherical ball 16a being positioned as closed to practical to the
imaginary line between the tip 12a and the centre of the rotational
means. The effect of tightening the securing bolt 20 causes the
forces on the tool holder 14, base 16 and retainer 18 to pass
through two points. The first of which is the radius point of the
mating faces of the spherical ball 16a and spherical indent 14a.
The second point of contact is the radius point of the mating face
of the retainer 18 and the base 16. As the radius point of the
mating faces of cutting tool holder 14 and the retainer 18 does not
fall along this line, a wedging action occurs upon securing the
fastening bolt 20. The tightening of the bolt 20 also causes a
moment arm around the radius point of the mating faces of the base
16 and the retainer 18.
[0070] Considering the environment the cutting tool holder
apparatus 10 would be exposed to, a substantial amount of debris
can enter into the assembly. Given the flexibility of the
components, the disassembling the cutting tool holder apparatus 10
can be made with minimal effort. By removing the securing bolt 20,
each of the components free, this allows for easier "change over"
of tools and general maintenance.
[0071] Due to the unique interconnection of the curved mating faces
of the three components under tensioning by the securing bolt 20,
the tool holder apparatus 10 solves the problem of having to
continually re-tension the bolt due to maximizing the transferal of
stress. This assists in reducing the costs of having to
repetitiously replace lost cutting tool holders and reducing the
time in maintenance and repairs. Further the components of the
invention do not need any finishing machine due to the self
alignment aspect which also reduces the costs.
[0072] As in the present invention, with high productivity, high
horsepower machine applications, wear is likely to be a problem on
the leading front face of the base. Since it is intended that this
component is not to be required to be replaced during the expected
life of the road or mining machine, it is advantageous to have a
sacrificial wear plate in front of the leading face that can easily
be replaced if necessary.
[0073] As shown in FIGS. 1, 2, 5, 6 and 7 and in detail in FIG. 11,
preferably, the sacrificial wear component 21, has two legs 21a,
that fit into two slots 16f, in the base when fitted. Wear will
occur on the face 21b and at some stage it will be necessary to
replace only the component. Since wear rates of cutting tool
holding apparatus are not consistent across the drums in such
machines some may need replacing before others are worn out. To
make a base with sufficient material as a sacrificial plate would
add substantially to the cost. The base must be made of such a
material as to be able to be welded to the drum and therefore a
large amount of material would be required over the life of the
machine. Furthermore, a small cast sacrificial wear component with
no machining or welding can be made very hard and highly abrasive
resistant at low cost. Preferably, when the tooth holder is secured
into position the sacrificial wear component cannot be removed from
the slots by the obstruction of the tooth holder.
[0074] It is envisaged that fine material from the cutting action
of the teeth will impact and build up between the sacrificial wear
component and the tooth holder and base and secure the sacrificial
wear component in position so as no wear occurs in the slots on the
base or the front face of the tooth holder. Suitably, the
sacrificial wear component may be replaced by removal of the
retainer and tooth holder. The wear component is preferably of a
high alloy steel or equivalent material.
[0075] Preferably, the tooth holder 14 has a slot in the rear of
the tooth holder which allows for the insertion of a tooth punch or
drift whereby the punch can be used as a lever to release the
retainer 18 from a tightened position by tapping the punch with a
hammer to apply an impact sufficient to release the taper lock
between the three components 18, 14, 16. The punch applies a force
to 18f.
[0076] It will of course be understood that while the foregoing has
been given by way of examples of this invention are intended to be
illustrating and not restrictive, all such and other modifications
and variations thereto as would be apparent to persons skilled in
the art are deemed to fall within the broad scope and ambit of this
invention as is herein set forth. The scope of the invention should
therefore, be determined with reference to the appended claims,
along with the scope of equivalents to which such claims are
entitled.
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