U.S. patent application number 11/461790 was filed with the patent office on 2007-03-08 for excavator teeth.
This patent application is currently assigned to Thomas Anthony Meyers. Invention is credited to John Robert De Wit, Bruce Alexander Leslie, Thomas Anthony Meyers.
Application Number | 20070051022 11/461790 |
Document ID | / |
Family ID | 46325841 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051022 |
Kind Code |
A1 |
Meyers; Thomas Anthony ; et
al. |
March 8, 2007 |
EXCAVATOR TEETH
Abstract
An excavator tooth system having a mounting nose having a
projecting spigot and a wear member (12) having at one end a socket
(18), the socket (18) being defined by spaced side walls and upper
and lower walls converging from a rearwardly facing socket opening
to a forward end of the socket. Each of the upper and lower walls
comprises a forward bearing face (8a) and a rear bearing face (7a)
separated by a forwardly convergent intermediate face. The front
and rear bearing faces (8a,7a) are substantially parallel to a
longitudinal axis (50) of the wear member and engage corresponding
bearing faces (8,7) in said spigot.
Inventors: |
Meyers; Thomas Anthony;
(Mackay, AU) ; Leslie; Bruce Alexander; (Goodna,
AU) ; De Wit; John Robert; (McDowall, AU) |
Correspondence
Address: |
BUCKINGHAM, DOOLITTLE & BURROUGHS, LLP
3800 EMBASSY PARKWAY
SUITE 300
AKRON
OH
44333-8332
US
|
Assignee: |
Thomas Anthony Meyers
Mackay Queensland
AU
|
Family ID: |
46325841 |
Appl. No.: |
11/461790 |
Filed: |
August 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10707290 |
Dec 3, 2003 |
|
|
|
11461790 |
Aug 2, 2006 |
|
|
|
Current U.S.
Class: |
37/455 |
Current CPC
Class: |
E02F 9/2833 20130101;
E02F 9/2883 20130101; E02F 9/2825 20130101 |
Class at
Publication: |
037/455 |
International
Class: |
E02F 9/28 20060101
E02F009/28 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 4, 2002 |
AU |
2002953089 |
Apr 15, 2003 |
AU |
2003901793 |
Claims
1. An excavator tooth system comprising: a mounting nose having a
projecting spigot; and, a wear member having at one end thereof a
socket, said socket being defined by spaced side walls and upper
and lower walls converging from a rearwardly facing socket opening
to a forward end of said socket, each of said upper and lower walls
respectively comprising a planar front socket bearing face and a
planar rear socket bearing face separated by a forwardly convergent
intermediate face, said front and rear socket bearing faces being
substantially parallel to a longitudinal axis of said wear member,
said mounting nose having complementary planar front and rear
spigot bearing faces on upper and lower surfaces thereof, said
front and rear spigot bearing faces being substantially parallel to
a longitudinal axis of said mounting nose and, in use, snugly
engaging with said front and rear socket bearing faces when said
wear member is located on said mounting nose.
2. A system as claimed in claim 1 wherein said forward end of said
socket forms an end bearing face.
3. A system as claimed in claim 2 wherein said end bearing face
extends transversely of said longitudinal axis.
4. A system as claimed in claim 1 wherein the wear member comprises
an adaptor having a front end adapted for releasable attachment
thereto of a digging point.
5. A system as claimed in claim 1 wherein said wear member includes
an aperture in at least one wall of said socket.
6. A system as claimed in claim 1 wherein said wear member includes
aligned apertures on opposite walls of said socket.
7. A system as claimed in claim 6 wherein said aligned apertures
extend through opposite side walls of said socket.
8. A system as claimed in claim 1 wherein at least portion of said
rear bearing face is of a width greater than said forward bearing
face.
9. A system as claimed in claim 1 wherein at least portion of said
rear bearing face is of a substantially a similar width to said
forward bearing face.
10. A system as claimed in claim 1 wherein said rear bearing face
is of an area greater than said forward bearing face.
11. A system as claimed in claim 1 wherein said socket opening has
a transverse width greater than the width of the forward end of
said socket.
12. A system as claimed in claim 1 wherein the side walls of said
socket taper convergently towards said forward end of said
socket.
13. A system as claimed in claim 12 wherein said side walls taper
convergently at an angle of from 8.degree. to 11.degree. relative
to said longitudinal axis of said wear member.
14. A system as claimed in claim 13 wherein said side walls taper
convergently at an angel of about 11.degree..
15. An excavation device having an excavator tooth system according
to claim 1.
16. An excavation device as claimed in claim 13 wherein said
mounting nose is attached thereto.
17. An excavation device as claimed in claim 13 wherein said
mounting nose is integrally formed therewith.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of pending U.S.
application Ser. No 10/707,290, filed Dec. 3, 2003.
FIELD OF THE INVENTION
[0002] This invention is concerned with improvements in excavator
teeth for earth excavating devices.
[0003] The invention is concerned particularly, although not
exclusively, with the mounting of excavator teeth adaptors to
adaptor noses on an excavating device such as an excavator bucket
or the like.
BACKGROUND OF THE INVENTION
[0004] Excavating teeth mounted to the digging edge of excavator
buckets and the like generally comprise a replaceable digging
point, an adaptor body and an adaptor nose which is secured by
welding to or is otherwise integrally formed with the digging edge
of an excavator bucket. The adaptor has a socket-like recess at its
rear end to receivably locate a front spigot portion of the adaptor
nose and a locking pin extends through aligned apertures in the
adaptor and nose to retain the adaptor in position.
[0005] In use, excavator teeth are subjected to extensive load
forces along a longitudinal axis of a tooth as well as in vertical
and transverse directions. A snug fit is required between the
digging point and the front portion of the adaptor and also between
the adaptor socket and the nose spigot portion and their respective
mounting pins to avoid premature wear between the components. As
the various components wear, the locking pins can loosen thereby
increasing the risk of loss of a digging point or an entire digging
tooth assembly.
[0006] The greatest loads experienced by excavator teeth are
vertical loads which tend to generate large moment forces capable
of rotating a tooth off the front of an adaptor and/or rotating the
adaptor off the adaptor nose.
[0007] Despite many prior art attempts to improve the mounting of
an adaptor to a nose, most of these proposals suffer from one or
more deficiencies.
[0008] U.S. Pat. No. 4,182,058 describes an excavator tooth having
a rearwardly divergent tapering socket to receive a nose having a
complementary-shaped front spigot portion. Resistance to rotational
moment forces is borne by a resilient steel cotter pin extending
through aligned vertical apertures in the socket and spigot
portions.
[0009] U.S. Pat. No. 3,023,521 also describes an excavator tooth
having a rearwardly divergent tapering socket to receive a
complementary-shaped tooth support spigot portion. Rotational
moment forces are resisted by a lip engaging in a recess in the
tooth support member.
[0010] U.S. Pat. Nos. 3,774,324, 4,338,736, 4,481,728 and 4,903,420
all describe nose and tooth combinations wherein the nose has a
generally convergently tapering spigot portion with a forward tip
having a box-like configuration with at least the upper and lower
surfaces thereof having faces parallel to each other and to a
longitudinal axis of the nose portion. With the exception of U.S.
Pat. No. 4,338,736, which describes a transverse locking pin, each
of the tooth mounting arrangements is heavily reliant on a large
vertical locking pin to resist rotational moment forces tending to
rotate the teeth off respective noses.
[0011] U.S. Pat. No. 4,231,173 describes a tapered adaptor nose
having a box-like free end, which engages in a mating box-like
socket cavity to resist rotational moments. Opposed pairs of
rearwardly extending tongues engage in corresponding recesses in
the outer surfaces of the adaptor nose to resist rotational
movements. Because the tongues themselves are unsupported, they
possess a limited capacity to resist rotational moment forces.
[0012] U.S. Pat. No. 5,272,824 describes a structure similar to
that of U.S. Pat. No. 4,231,173 except that the side tongues are of
more robust dimensions and the upper and lower tongues are formed
as box-like members with apertures to receive a vertical mounting
pin passing through aligned apertures in the tooth and adaptor
nose.
[0013] U.S. Pat. Nos. 3,196,956 and 4,404,760 provide flat rail
surfaces on the adaptor nose to engage with mating grooves in the
socket aperture of a corresponding tooth. In the case of U.S. Pat.
No. 3,196,956, the mating rail and groove surfaces are forwardly
tapered, whereas in U.S. Pat. No. 4,404,760 the mating rail and
groove surfaces are generally parallel to the longitudinal axis of
a tooth.
[0014] U.S. Pat. No. 5,423,138 describes a generally tapered nose
having a box-like front end with upper and lower transverse
surfaces generally parallel to a longitudinal axis of a tooth. The
parallel upper and lower transverse surfaces are contiguous with
upper and lower rail surfaces on each side of the nose and parallel
to the longitudinal axis of the tooth. A pair of rearwardly
extending side tongues locate in recesses formed in the outer side
faces of the nose, ostensibly to resist rotational moment forces in
the tooth. Because the side tongues are recessed to accommodate the
side rail portions, the robustness of the side tongues is somewhat
compromised
[0015] U.S. Pat. No. 4,233,761 describes a fairly stubby tapered
nose having a box-like front portion with upper and lower surfaces
generally parallel to a longitudinal axis of an excavator tooth, an
intermediate rearwardly diverging tapered portion and a rear
portion having upper and lower surfaces extending generally
parallel to a longitudinal axis of the tooth. Formed on the upper
and lower surfaces of the front, intermediate and rear portions of
the nose are spaced parallel reinforcing ribs which are located in
mating grooves in the excavator tooth. A large vertical locking pin
extends through aligned apertures in the tooth and nose between the
reinforcing ribs. This structure is heavily reliant on the locking
pin to resist rotational moment forces however it is considered
that this configuration may be prone to failure in the rear portion
of the adaptor.
[0016] U.S. Pat. No. 5,709,043 describes a nose/adaptor combination
wherein the adaptor socket tapers convergently towards a box-like
front portion having upper and lower bearing surfaces generally
parallel to a longitudinal axis of the tooth, a front transverse
upright bearing surface and rearwardly divergent bearing surfaces
formed at obtuse angles between the converging upper and lower
walls and the side walls of the socket, ostensibly to avoid areas
of stress concentration.
[0017] U.S. Pat. No. 6,018,896 describes a pin/retainer system for
locking an excavation tooth onto an adaptor wherein the retainer is
inserted in the adaptor and a wedge-shaped pin is driven into
aligned apertures in the tooth and adaptor to resiliently engage
with the retainer.
[0018] United States Publication No US 2002/0000053A1 describes a
mechanism for releasably retaining an adaptor into the nose of a
bucket lip or the like wherein a tapered threaded socket is
non-rotatably located on the inside of an aperture in the side wall
of the adaptor. A threaded retaining pin extends through the
threaded socket and locates in an aligned aperture in the bucket
nose.
[0019] U.S. Pat. No. 5,337,495 describes a tooth point slidably
locatable over a tapered adaptor front portion, the tooth point
being releasably secured on the adaptor by a pair of cap screws
extending through apertures in the side walls of the tooth into
threaded inserts located in recesses on opposite sides of the
adaptor front portion. The inserts have a shouldered face and a
curved face nestable in complementary-shaped adaptor recesses to
prevent rotation when the cap screws are threadably located
therein.
[0020] U.S. Pat. No. 5,172,501 described attachment of a digging
point to an adaptor by a threaded bolt extending through an
aperture in a point for threaded engagement in a threaded opening
in the adaptor. Other retention systems for digging points on
adaptors or adaptors on noses are described in U.S. Pat. Nos.
6,119,378, 6,467,204, 6,052,927 and 6,467,203.
[0021] Other devices for removably securing replaceable wear
elements on earth working equipment such as a retaining pin, a
bolt, a pin lock, a spool and wedge system or a flex pin are
described in U.S. Pat. Nos. 3,839,805, 3,982,339, 4,587,751 and
5,716,667 respectively.
[0022] U.S. Pat. No. 5,937,550 describes a lock assembly for
releasably securing an adaptor to a nose of an excavator support
structure. The lock assembly comprises a body and a base coupled
together and adapted for insertion, while coupled together, in a
hole in the nose of the support structure. The length of the lock
assembly is extended to secure the adaptor and is retracted to
release the adaptor. While adequate for securing an adaptor to a
nose of an excavator support structure, the lock described in this
patent is relatively complex in design and operation leading to
high costs and labour intensive extraction procedures in the
field.
[0023] Canadian Patent Application No 2,161,505 describes a system
for removably retaining an excavation point on an adaptor with at
least one flanged sleeve having a screw-threaded aperture therein,
the flanged sleeve being non-rotatably locatable in a transverse
bore in the adaptor before fitment of the point onto the adaptor. A
screw-threaded pin is inserted into the sleeve via an aperture in
the point whereby portion of the head of the pin retains the point
on the adaptor.
[0024] U.S. Pat. No. 6,708,431 discloses an excavator tooth system
comprising a mounting nose and an adaptor for removable attachment
thereto by engagement between a spigot-like projection on the
mounting nose and a socket-like recess in the rear portion of the
adaptor. The mounting nose is described as having a horizontally
elongated elliptical cross-section along its length and the tapered
tip of the nose is shown as having crescent shaped upper and lower
front bearing surfaces which lie parallel to each other. The rear
bearing surfaces of the mounting nose are formed as longitudinally
and transversely arcuate surfaces tapering convergently towards the
tapered tip of the nose. The socket-like recess in the adaptor has
internal wall surfaces generally complementary to the contours of
the mounting nose and there is a snug fit between the front and
rear bearing surfaces of the mounting nose and complementary
internal contours of the adaptor.
[0025] While generally satisfactory for their intended purpose, the
abovementioned prior art adaptor/nose combinations all suffer from
one or more shortcomings or disadvantages in terms of inadequate
resistance to rotation of an adaptor off a nose under the influence
of vertical loads applying a rotational moment to the adaptor, a
predisposition to premature wear, difficulties in retention of the
adaptors on noses, inadequate locking systems and unduly
complicated configurations giving rise to increased fabrication
costs.
[0026] It is an aim of the present invention to overcome or
alleviate at least some of the abovementioned prior art
disadvantages or otherwise to provide consumers with a convenient
choice.
SUMMARY OF THE INVENTION
[0027] According to one aspect of the invention there is provided
an excavator tooth system comprising: [0028] a mounting nose having
a projecting spigot; and, [0029] a wear member having at one end
thereof a socket, said socket being defined by spaced side walls
and upper and lower walls converging from a rearwardly facing
socket opening to a forward end of said socket, each of said upper
and lower walls respectively comprising a planar front socket
bearing face and a planar rear socket bearing face separated by a
forwardly convergent intermediate face, said front and rear socket
bearing faces being substantially parallel to a longitudinal axis
of said wear member, said mounting nose having complementary planar
front and rear spigot bearing faces on upper and lower surfaces
thereof, said front and rear spigot bearing faces being
substantially parallel to a longitudinal axis of said mounting nose
and, in use, snugly engaging with said front and rear socket
bearing faces when said wear member is located on said mounting
nose.
[0030] Suitably, said forward end of said socket forms an end
bearing face.
[0031] If required, said end bearing face may extend transversely
of said longitudinal axis.
[0032] The wear member may comprise an excavator tooth having a
digging edge at a front end thereof.
[0033] Preferably, the wear member comprises an adaptor having a
front end adapted for releasable attachment of a digging point.
[0034] Suitably, said wear member includes an aperture in at least
one wall of said socket.
[0035] Preferably, said wear member includes aligned apertures on
opposite walls of said socket.
[0036] If required, said aligned apertures may extend through upper
and lower socket walls.
[0037] Preferably, said aligned apertures extend through opposite
side walls of said socket.
[0038] If required, at least portion of said rear bearing face is
of a width greater than said forward bearing face.
[0039] At least portion of said rear bearing face may be of
substantially a similar width to said forward bearing face.
[0040] Suitably, said rear bearing face is of an area greater than
said forward bearing face.
[0041] The socket opening may have a transverse width greater than
the width of the forward end of said socket.
[0042] If required, the side walls of said socket may taper
convergently towards said forward end of said sockets.
[0043] Alternatively, the side walls of said socket may be
stepped.
[0044] According to another aspect of the invention there is
provided an excavation device having an excavator tooth system
according to a first aspect of the invention and wherein said
mounting nose is integrally formed with said excavation device.
[0045] Alternatively, said mounting nose may be attached to said
excavation device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] In order that the invention may be more fully understood and
put into practical effect, reference will now be made to the
accompanying drawings in which:
[0047] FIG, 1 shows portion of an adaptor nose;
[0048] FIG. 2 shows an exploded view of an excavator tooth system
according the invention.
[0049] FIG. 3 shows schematically an upright cross-sectional view
showing the engagement between a mounting nose and an adaptor
according to the invention.
[0050] FIG. 4 shows in transverse cross-section a locking pin for
releasable attachment of the adaptor to the mounting nose;
[0051] FIG. 5 shows in transverse cross-section the locking pin of
FIG. 4 in a locked position;
[0052] FIG. 6 shows schematically a transverse cross-sectional view
of an excavator tooth system according to one aspect of the
invention;
[0053] FIG. 7 shows a lip for an excavation device which is adapted
in accordance with the invention;
[0054] FIG. 8 shows an exploded view of the lip of FIG. 7 and
excavator teeth systems;
[0055] FIG. 9 shows the arrangement of FIG. 8 in an assembled
state;
[0056] FIG. 10 shows a lock for releasable attachment of the
adaptor to the mounting nose;
[0057] FIG. 11 shows a longitudinal cross sectional view of a
retaining member of the lock of FIG. 10; and
[0058] FIG. 12 shows a longitudinal cross sectional view of a body
member of the lock of FIG. 10.
DETAILED DESCRIPTION OF THE DRAWINGS
[0059] In the accompanying drawings, for the sake of clarity, like
reference numerals are employed for like features where
appropriate.
[0060] In FIG. 1, the mounting nose 1 is shown as integrally formed
with a cutting lip 2 of an excavation device such as a dragline
bucket or the like (not shown).
[0061] Nose 1 includes a pair of opposed tapered forwardly
convergent side faces 3, a front face 4 and upper and lower faces
5,6 converging towards front face 4. Upper and lower faces 5, 6
each include planar rear bearing faces 7 and planar forward bearing
faces 8 separated by a tapered generally planar intermediate face
9. Rear bearing faces 7, forward bearing faces 8 and front bearing
faces 10 are all shown as shaded regions for the sake of clarity.
Side faces 3 may be tapered at an angle of from 8.degree. to
15.degree. degrees relative to a longitudinal axis X of the
mounting nose. Preferably, side faces 3 are tapered at about
11.degree. to longitudinal axis X.
[0062] Rear bearing faces 7 are parallel to each other as are
forward bearing faces 8. Each of rear and forward bearing faces 7,8
are also parallel to longitudinal axis X of the mounting nose
1.
[0063] Extending transversely of mounting nose 1 is an adaptor
mounting aperture 11. Aperture 11 is generally oval in
cross-sectional shape with the longer oval axis extending generally
parallel to nose axis X. Aperture 11 is positioned closer to top
face 5 than bottom face 4, the purpose of which positioning will be
described in detail later.
[0064] In a conventional tapered wedge-shaped adaptor nose there is
a substantial rotational moment to a digging point in the region of
the adaptor tip. This rotational moment force is resisted by
normally directed forces in the rear of the upper and lower wedge
faces and frictional forces in the upper wedge face. If the
rotational moment is small compared with the normally directed
forces on the upper wedge face, the frictional forces produced by
the normally directed forces can be sufficient to withstand the
rotational moment. For a digging point this usually is the case
because as the moment force on the digging point is applied almost
directly above the upper face of the wedge, the moments are small
compared to the normal forces and the corresponding frictional
forces are sufficient to retain the digging point in place.
[0065] In the case of the mounting between a wedge-shaped or
tapered adaptor nose and the adaptor itself, the frictional forces
are insufficient to withstand the rotational moment to prevent the
adaptor from simply rotating off the nose under load. To overcome
this it is customary with wedge-shaped adaptor noses to employ a
substantial pin to retain the adaptor in place as the pin must
withstand very large forces applied thereto. Typically, this
necessitates a vertically oriented pin.
[0066] In the present invention, the key bearing faces are
configured to be generally planar and parallel to the longitudinal
axis of a wear member such as an adaptor. The wear member is thus
cantilevered on the nose whereby the rotational moment is resisted
by the high load forces applied to the upper forward bearing face
and the lower rear bearing face. Generally speaking the higher
those load forces, the higher the friction available to hold the
adaptor or wear member onto the nose. Because the bearing faces are
substantially planar and parallel, an adaptor cannot rotate off its
nose.
[0067] The excavator tooth system according to the invention in
effect becomes self-locking by virtue of its high internal
frictional forces. As a consequence, the role of the retaining pin
is substantially reduced from being a major structural component in
prior art systems to being a device which simply stops the wear
member from falling off a nose.
[0068] FIG. 2 shows an exploded view of an excavator tooth assembly
according to one aspect of the invention.
[0069] As shown, the assembly comprises a mounting nose 1 (shown
partially), an adaptor 12 and a replaceable digging point 13.
[0070] Adaptor 12 includes a hollow recess or socket (not shown) to
receive the nose 1. Adaptor 12 is retained on nose 1 by a spool and
wedge pin 14 which extends through oval-shaped apertures 15 in the
adaptor body when aligned with aperture 11 in nose 1. Point 13 is
releasably retained on the front tip of adaptor 12 by a retaining
pin (not shown) extending through aligned apertures 16,17 in the
point 13 and adaptor 12 respectively.
[0071] FIG. 3 is a schematic vertical cross-sectional view through
the nose 1 and adaptor 12 of FIG. 2 and shows the engagement of the
planar parallel bearing surfaces of the nose and adaptor.
[0072] When the spool and wedge pin 14 is tensioned nose 1 is
firmly located in the socket cavity 18 of adaptor 12 with the front
bearing face 10 of nose 1 in abutment with corresponding bearing
face 10a in adaptor 12. Similarly, rear and forward bearing faces 7
and 8 are abutted against corresponding bearing faces 7a,8a
respectively in adaptor 12.
[0073] FIG. 4 is a partial schematic transverse cross-sectional
view through the nose/adaptor combination shown in FIG. 3.
[0074] As shown, spool and wedge retaining pin 14 is in an extended
unlocked position with the shoulders 20 of pin body 21 being
located behind the rear inner edges of apertures 15. A threaded
bolt 22 is rotatably journalled in one end of pin body 21 and its
other end is engaged in a threaded aperture 23 in wedge member 24.
As bolt 22 is rotated, it draws wedge member 24 into the aligned
apertures 15,11 of adaptor 12 and nose 1 respectively until it
wedges adaptor 12 into tight engagement with nose 1 as shown in
FIG. 5.
[0075] As can be seen in FIG. 5, retaining pin 14 is in a retracted
locking position with the free ends thereof slightly recessed into
apertures 15.
[0076] FIG. 6 shows a schematic transverse cross-sectional view
through the assembly of FIG, 2 when in an assembled state.
[0077] FIG. 7 shows another aspect of the invention.
[0078] Depicted is a cutting lip 30 of an excavation device such as
a dragline bucket (not shown).
[0079] Cutting lip 30 is cast as an integral component from a
suitably wear resistant metal alloy and comprises a transverse
cutting bar 31, cheek plates 32 and mounting noses 1 at spaced
intervals therealong.
[0080] Noses 1 are faired back into cutting bar 31 forming recessed
regions 33 between adjacent noses. At the front portion of each
cheek plate 32 are mounts 34 for attachment of replaceable cutting
edges (not shown).
[0081] FIGS. 8 and 9 respectively show an exploded view and an
assembled view of the cutting lip 30 of FIG. 7 with adaptors 12 and
digging points 13 of FIG. 2.
[0082] In the assembly of FIG. 9, lip shrouds 35 are removably
secured in the recessed regions of bar 31 to minimize wear on the
lip assembly. As can be seen from FIG. 9 and also from FIGS. 1 and
3, the aligned pin apertures 11,15 of nose 1 and adaptor 12
respectively are displaced vertically upward relative to a
transverse plane occupied by the longitudinal axis X as shown in
FIG. 1, which axis lies in a central plane of nose 1. By having the
mounting apertures offset from a central position, the retaining
pins can be removed or installed without needing to remove the lip
shrouds 35. In turn, this permits the face of the lip shroud 35 to
be located at its optimal position with the face of the shroud
running along the centre line of the tooth assembly.
[0083] It readily will be apparent to persons skilled in the art
that many variations and modifications may be made to the invention
without departing from the spirit and scope of the invention.
[0084] For example, as the key digging forces are taken up by the
socket and spigot fitting between the nose and the wear member or
adaptor; the retaining pin can be of any design as it functions
merely to hold the wear member in place on the nose and otherwise
does not constitute a load bearing member.
[0085] FIG. 10 shows lock 36 being an alternative embodiment of a
locking pin.
[0086] FIG. 11 shows a longitudinal cross sectional view of the
retaining member 38 illustrated in FIG. 10.
[0087] FIG. 12 shows a longitudinal cross sectional view of the
body member 37 of FIG. 10.
[0088] As shown in FIGS. 10 to 12 the locking pin 36 comprises a
body member 37 wherein the body has an oval shaped cross section of
substantially identical configuration as the cross sectional shape
of aperture 11 in mounting nose 1 as illustrated in FIG. 3. As can
be seen in FIG. 10, the centre of screw-threaded aperture 45 is
displaced from the intersection of the longer and shorter axis of
the oval shaped cross section of body member 37. However, the
centre of screw-threaded shaft remains on the longer axis, the
reason for which will be discussed in detail below.
[0089] In use, both of retaining members 38 are withdrawn from each
screw-threaded aperture 45 of body member 37 independently of
mounting nose 1. Body member 37 is fully inserted into aperture 11
on mounting nose 1 of an excavator bucket as shown in FIG. 3, FIG.
4 and FIG. 5. Adaptor 12 is then located on mounting nose 1. As
seen in these figures, aperture 15 on adaptor 12 is partially
misaligned with aperture 11 on mounting nose 1 when adaptor 12 is
located on mounting nose 1. This partial misalignment captively
retains body member 37 within aperture 11 while mounting nose 1 is
located on adaptor 12. Furthermore, body member 37 is prevented
from rotating within aperture 11 due to the oval shaped cross
section of body member 37 being complementary with oval shaped
aperture 11.
[0090] Referring specifically to FIG. 4 and FIG. 5, even though
body member 37 is captively retained within aperture 11 due to the
misalignment of aperture 11 and aperture 15, screw-threaded
aperture 45 of body member 37 is still not covered by adaptor 12
and hence remains accessible. This is due to screw-threaded
aperture being offset from the centre of body member 37 as
described above.
[0091] To retain adaptor 12 on mounting nose 1, retaining members
38 are inserted through apertures 15 and 11 at opposite ends of
body member 37 such that the screw-threaded shaft 41 of each
retaining member is coupled with the screw-threaded aperture 45 at
either end of the body member 37. When tapered shoulder portion 40
abuts tapered recess 44, at least some of head portion 39 is
located within aperture 15 on either side of adaptor 12. This
protrusion of the head portion 39 at either end of lock 36 prevents
adaptor 12 from sliding off mounting nose 1. As discussed above,
lock 36 may be used with only a single retaining member 38 to
retain adaptor 12 on mounting nose 1.
[0092] To remove adaptor 12 from mounting nose 1 retaining members
38 are decoupled from body member 37. This is facilitated by
removing screw-threaded shaft 41 of each retaining member 38 from
screw-threaded aperture 45 at either end of body member 37. Adaptor
12 can then be removed from mounting nose 1 as head portion 39 of
each retaining member 38 no longer retains the adaptor on the
mounting nose. Once adaptor 12 has been removed, body member 37 can
be extracted from aperture 11.
[0093] Lock 36 is self-locking and self-aligning due to the
abutment of tapered shoulder portion 40 with tapered recess 44.
This tapered contact provides for greater frictional gripping
between body member 37 and retaining member 38 than a conventional
square shouldered contact. A person skilled in the art will
recognise the analogy between the tapered contact made between
retaining member 38 and body member 37 and the configuration of a
wheel nut. Hence, retaining member 38 remains in secure contact
with body member 37 while in use and retains adaptor 12 on nose 1.
When it is necessary to remove adaptor 12 from nose 1 the tapered
contact provides for an easy release of retaining member 38 from
body member 37 thus reducing the time necessary to change the
adaptor leading to increased efficiency.
[0094] Furthermore, the tapered contact accounts for manufacturing
tolerances of member 37 and retaining member 38 as the lock is
self-aligning when tapered shoulder portion 40 proceeds into
tapered recess 44, and the retaining member is tightened, the
tapered contact guides retaining member 38 and body member 37 into
alignment.
[0095] The tapered contact also prevents the passage of water
within screw-threaded aperture 45 and hence reduces the risk of
corrosion of lock 36 although, preferably, an anti-corrosive grease
would still be applied to the components of lock 36 to ensure that
no corrosion occurs.
[0096] The contact between tapered shoulder portion 40 and tapered
recess 44 also allows for the efficient transfer of any load on
head portion 39 to body member 37 rather than to the thread of
screw-threaded shaft 41. Hence, the only means by which lock 36 may
fail is if head portion 39 is sheared from screw-threaded shaft 41
and it is envisaged that such a force will not be encountered in
normal operation.
[0097] Lock 36 provides for an elegantly simple system for
releasably retaining a wear member to a mounting nose of an
excavator bucket. The lock is relatively cheap to manufacture and
is easy to use in the field while still providing a secure
attachment means.
[0098] While resilient plugs may be employed to plug the locking
pin apertures of FIGS. 2 to 6 to stop ingress of particulate matter
which might otherwise constitute an abrasive material, entry of
dirt into the small spaces between the flat faces of the socket and
spigot members of the assembly tend to pack tightly and actually
prevent relative movement between the nose and the wear member thus
reducing, rather than increasing, internal wear between
components.
[0099] Throughout this specification, unless the context requires
otherwise, the word "comprise", and variations such as "comprises"
or "comprising", will be understood to imply the inclusion of a
stated integer or group of integers or steps but not the exclusion
of any other integer or group of integers.
[0100] This invention has been described in detail with reference
to specific embodiments thereof, including the respective best
modes for carrying out each embodiment. It shall be understood that
these illustrations are by way of example and not by way of
limitation.
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