Note: Descriptions are shown in the official language in which they were submitted.
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WO 96!08612 PCT/AU94/00555
HYDRAULIC FASTENING DEVICE AND METHOD
Background of the Invention
The present invention relates to a hydraulic fastening device and method, and
in
particular to such a device and method useful in the mining or earthmoving
industry for
attaching teeth or wear plates to bucket drag lines of such implements and the
like.
The present invention is however useful for attaching any two components
together which might normally be joined by some form of mechanical joining
mechanism,
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Description of the Prior Art
There are in existence different methods of using wedge and spool assemblies
for
connecting implements such as teeth and/or adaptors to drag lines buckets and
the like
which methods include that described in the applicant's International PCT
Patent
Application No. PCT/AU94/00035. That application discloses a spool and wedge
assembly which comprises an array of wedges which co-operate to enable secure
fitting
of teeth to the buckets.
In the heavy earthworks industry, buckets attached to heavy earthmoving
equipment are adapted with leading edge implements for cutting or moving
overburden.
These implements, commonly referred to as teeth, must by necessity be
replaceable due
to heavy wear and tear.
Teeth are generally fixed to a bucket in one of two ways. In the case of
smaller
buckets the teeth are detachably fixed directly to an adaptor formed integral
with the
bucket generally known as a bucket nose. In the case of the larger buckets the
teeth are
fitted via an adaptor which attaches to a specifically configured formation in
the bucket
leading edge. The teeth and adaptors are subjected to heavy wear and must be
regularly
replaced with the life of the teeth and adaptor generally dictated by the
nature of over
burden that the bucket is required to move. In the case of drag lines the wear
is
significant. According to the prior art the teeth are generally wedge shaped
and attach
to the leading edge of the adaptor by pin encapsulation, the pin connecting
the spool and
wedge assembly.
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The adaptor mates at its trailing end to the bucket leading edge. At present,
this
particular attachment is effected by a known spool and wedge, assembly which
comprises
a generally elongated truncated cylindrical spool and a wedge which mutually
cooperate
to secure the adaptor to the bucket. Buckets usually have a multiplicity of
such spool and
wedge assemblies spaced apart along the leading edge of the bucket generally
commensurate with the number of teeth on the bucket. In the case of large
buckets there
could be half a dozen or more assemblies which require constant replacement.
Not only do these assemblies require replacement after excessive wear, they
also
require constant monitoring during use to ensure that they do not become
sloppy and
loose thereby inhibiting the efficiency of the operation of the teeth.
Presently, according to one method, in order to fit the wedge and spool
assembly,
the wedge and spool arz placed into recesses formed in both the adaptor and
bucket,
which are aligned when the adaptor is fitted to the bucket. When the adaptor
is fitted to
the bucket, this recess is axially aligned. The wedge element is then driven
home axially
1 S by a sledge hammer, to secure the adaptor to the bucket. A tight fit is
ensured by
jamming the wedge against the spool. At present, the spool and wedge assembly
extends
axially downwardly beyond the periphery of the underside of the adaptor and
bucket.
The extension engages the ground during use of the bucket and causes the
adaptor to
become loose as the wedge and spool work loose. This occurs particularly in
circumstances where the bucket is used to excavate hard and rocky ground.
Personnel
are employed to regularly check the integrity of the connection of the
adaptor. Where
the fit works loose, due to movement of the wedge and spool assembly, it must
be
constantly hammered to tighten the connection. This is a labour intensive and
physically
demanding activity. Likewise, when a spool and wedge assembly is to be
released to free
the adaptor from the bucket the assembly must be violently hammered to remove
it and
generally from underneath the bucket. For this purpose the bucket must be
lifted up to
enable a labourer to gain access to the distal end of the assembly. Due to the
intensely
physical nature of this work, many men are required to fit and remove the
adaptors and
to check and ensure tightness of the fit.
According to the prior art methodology, trades people, such as fitters, are
employed to fit the spool and wedge assemblies to the buckets. The spool and
wedge
assembly is inserted into the recess in the implement to be fitted to the
bucket. The
wedge is hammered with a sledge hammer to drive the wedge home. Once a tight
fit is
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achieved the bucket is used a small number of times and then rechecked. If
loosening
occurs the fitter drives the wedge in even further until it is tight enough to
allow
continued operation of the bucket. At that time any part of the wedge and
spool
assembly which extends beyond the extremity of the implements fitted to the
bucket are
removed by means of an oxy acetylene cutter.
The difficulty with removing the head piece and tail piece of the wedge and
spool
assembly is that if it again becomes loose it is difficult for the fitter to
hammer the top
of the wedge as it is flush with the surface of the implement fitted to the
bucket.
Also, when an implement such as a tooth is finally wom out it can sometimes be
so difficult to remove the spool and wedge assembly that it is necessary to
cut through
the old tooth or adaptor in order to remove the assembly. This clearly adds to
the cost
of fitting and maintaining the prior art wedge and spool assemblies.
The applicant has previously addressed this problem, one solution to which has
been made the subject of aforesaid International PCT Patent Application No.
PCT/AU94/00035. That application discloses an alternative foam of spool and
wedge
assembly, and comprises a spool and wedge assembly for use in connecting an
implement
to the nose of an earth moving bucket. The spool and wedge assembly comprises
first
and second spools, first and second wedges, and, a bolt assembly for joining
the first and
second wedges. When the bolt is turned in one direction the wedges are drawn
towards
each other thereby urging the spools apart and against the wall of a recess in
which said
spool and wedge assembly is placed thereby securing said implement to said
bucket. As
an alternative to the bolt assembly a threaded shank with a hexagonal nut may
be used.
That invention has major advantages over the prior art particularly in its
facility
for convenient releasable attachment of implements to the buckets.
Summar~r of the Invention
The present invention seeks to provide a further alternative to the
applicant's own
previous invention and in doing so to ameliorate the aforesaid disadvantages.
The present invention seeks to provide a convenient method for fitting,
adjusting
and/or removing a wedge and spool assembly.
The invention also seeks to provide a wedge and spool assembly adapted for
ease
of fitting, adjustment and release of a tooth or like implement and/or adaptor
from an
earthmoving bucket.
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WO 96!08612 PCT/AU94/00555
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In one broad form, the present invention provides a hydraulic fastening
device, for
securement of two components, each component having an orifice or cavity at
least partly
therethrough adapted to be substantially coaxially aligned, said fastening
device
comprising:
a substantially elongate body member adapted to be inserted substantially
within
said orifice or cavity of each component when substantially coaxially aligned;
a fluid conduit within said body member containing a fluid therein;
at least one movable protrusion means in contact with said fluid, adapted to
protrude in a substantially transverse direction from said elongate body
member; and,
cnnt~oi_ means to control the movement of said at least one protrusion;
such that, upon ~~peration of said control means, said at least one protrusion
is
moved to a protruded position to fasten said two components.
Preferably, said control means is a valve mechanism to permit the
ingress/egress
of fluid to/from said fluid conduit,
such that, upon the ingress of fluid, said protrusions) protrude from said
body
member, and, upon the egress of fluid, said protrusions) retract within said
body
member.
Alternatively, but also preferably, said control means comprises a piston
device,
such that, when said piston device is actuated, a compressive force is applied
to
said fluid to cause said protrusions) to protrude from said body member, or, a
decompressive force is applied to said fluid to cause said protrusions) to
withdraw into
said body.
In a preferred form of the invention a first of said components is a bucket or
other
component of an earthmoving or mining equipment, or the like; and,
a second of said components is one or more teeth, adaptors or the like, to be
attached to said earthmoving or mining equipment, or the like.
In a fwther preferred form said first component is embodied as an outwardly
projecting member and is provided with a transverse orifice therethrough; and,
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said second component is of complementary shape with a hollow centre portion,
adapted to substantially surround said projecting member such that
orifice(s)/cutout(s)
provided on either side thereof are adapted to be substantially axially
aligned with said
orifice of said first component;
such that, when said orifice(s)/cutout(s) of said components are substantially
aligned, said body member may be inserted and fastened therein.
Perhaps most preferably said body member is substantially cylindrical in
shape.
In a further broad form, the present invention provides a method of fastening
two
components, wherein each of said components are of complementary shape and are
provided with an orificF and/or cutout therein, comprising the steps of:
positioning said two components such that their respective
orifice(s)/cutout(s) are
substantially aligned;
inserting a fastening device within said joined orifice(s)/cutout(s),
characterised
in that said fastening device comprises a substantially elongate body member
provided
with a fluid conduit, at least one protrusion means, and control means to
hydraulically
control the movement of said protrusion means;
operating said control means such that said protrusion means extends
substantially
transversely of said body member such that said components become
substantially
fastened.
Brief Description of the Drawines
The present invention will become more fully understood from the following
detailed description of preferred but non-limiting embodiments thereof,
described in
connection with the accompanying drawings, wherein:
Fig. 1 shows an exploded view of a prior art spool and wedge assembly;
Fig. 2 shows a cross sectional view of the prior art device, in an assembled
manner;
Fig. 3 shows a cross sectional view of the fastening device according to a
preferred embodiment of the invention in assembled form;
Fig. 4 shows a side elevational view of the body member of the fastening
device;
Fig. 5 shows a side elevational view of the body member of the device, rotated
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90 degrees;
Fig. 6 shows an end view of the device;
Fig. 7 shows a cross sectional view of the device, detailing the fluid
conduit; and,
Fig. 8 shows the piston like movable protrusion means and associated sealing
rings .
which act in fastening the device.
Detailed Description of the Preferred Embodiments
Referring to Fig. 1 and 2 there is shown cross sectional views of the
applicant's
prior art spool and wedge assembly 1, Fig. 1 showing an exploded view, and
Fig. 2
showing the device in assembled form. The assembly comprises first and second
opposing spool members 2 and 3 respectively, and includes first and second
wedge
members 4 and 5 linked by means of bolt 6. Bolt 6 is adapted with hexagonal
head 7
which preferably fits within recess 8. Bolt 6 also has threaded portion 9
which threadably
engages first wedge member 4.
Fig. 2 shows a cross sectional assembled view of the assembly 1 fitted within
a
passage 9 in bucket nose 10. Passage 9 aligns with passage 11 in adaptor 12.
Passages
9 and 11 are substantially in axial alignment when the adaptor is properly
fitted to the
bucket nose 10. When an adaptor is to be fitted to the bucket nose 10, the
passages are
first aligned so as to enable feeding therein of assembly 1 in a loosely
assembled form.
When the assembly 1 is in position, the user rotates head 7 of bolt 6 in a
first direction
which urges wedges 4 and 5 towards each other. When the assembly 1 is in
position the
wedges 4 and 5 abut spools 2 and 3. Contact between wedge 4 and spools 2 and 3
takes
place via abutment of surface 13 against surface 14 and abutment of surface 15
against
surface 16. Similarly, contact between wedge 5 and spools 2 and 3 takes place
via
abutment of surface 17 against 18 and surface 19 against 20. The caroming
action
generated between the aforesaid contacting surfaces induces a wedging effect
and urges
spools 2 and 3 in opposing directions and against the wall 21 in the case of
bucket nose
10 and wall 22 in the case of adaptor 12 of passages 9 and 11 respectively.
Referring to Fig. 3 there is shown a cross sectional view of an alternative
fastening arrangement 25 according to a preferred embodiment of the invention.
The
preferred embodiment in the invention will be described according to its use
as a
hydraulic wedge assembly as an alternative device to the spool and wedge
assembly of
Figs. 1 and 2. It should be appreciated that the hydraulic fastening device is
adaptable
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WO 96/08612 PCT/AU94/00555
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to a wide variety of applications far beyond replacement of a prior art
mechanical spool
and wedge device.
Assembly 25 generally comprises a substantially elongate body member 26
adapted to be inserted substantially within orifices or cavities of the pair
of components.
S In the illustrated embodiment of Fig. 3, a first of the components is an
outwardly
projecting member 29 provided on a bucket or other component of an earthmoving
or
mining equipment. Component 29 is provided with an orifice 50 transversely
therethrough. The second component is a complementary shaped component 51
which
is adapted to be secured to the first component 29. A second component S 1 is
adapted
to substantially surround the projecting member 29, and is also provided with
an orifice
52 therethr~ugh. The orifice 52 is adapted to substantially coaxially align
with the orifice
51 such that the fastening device may be inserted therein. As will be seen,
when the first
component 29 is substantially aligned with the second component 51, the body
member
25 may be inserted therein, as shown in Fig. 3.
Fig. 4 shows a side view of the device 25, whilst Fig. 5 shows another side of
it,
rotated through a 90° angle.
Fig. 6 shows an end view of the device of Fig. 3 to 5. Fig. 7 shows a cross-
sectional view of the device, and Fig. 8 shows details of the.projection
members and
sealing means, of the fastening device.
The operation of the hydraulic fastening device will now be described in
relation
to Fig. 7. As the cross-sectional view of Fig. 7 shows, the device 26 is
provided with a
fluid conduit 32 therein, formed by a central cavity or channel 33, a pair of
channels 38
and 39 leading to chambers 36 and 37, respectively. The fluid conduit and the
chambers
are adapted to receive grease or other fluid substance therein. In the case of
grease, a
grease nipple 34 is provided to permit the ingress or egress of grease to and
from the
conduit 32. A pair of pistons or protrusion members, such as detailed in Fig.
8 and
shown by reference numerals 40 and 41, are adapted to be provided within the
chambers
36 and 37 and be movably displaced in a direction transverse to the
longitudinal direction
of the body member 26. The piston or protrusion members 40 and 41 are provided
with
suitable O-ring type seals or the like to ensure that good movement of the
pistons 40 and
41 is enabled without the loss of fluid from within the fluid conduit.
Suitable type rings
are shown in Fig. 8 and illustrated by the numerals 60 and 61.
The actuation of the pistons or protrusion members 40 and 41 will now be
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described in relation to this application to earth moving or mining equipment.
When an element such as a tooth or adaptor is to be fitted to an earth moving
bucket, the main body member 26 is provided to within the recess or orifice
formed
between the two components 29 and 51. Once the main body member 26 is in
position,
a grease gun is attached to the nipple 35, and grease is supplied to within
the fluid
conduit 32, such that pistons 40 and 41 which fit snugly within the cavities
36 and 37 are
urged beyond the periphery 42 of the body member 26. Depending upon how much
grease is supplied to within the fluid conduit 32, the pistons 40 and 41 may
be advanced
to a further or lesser distance. By way of example, the pressure required to
advance the
piston the small distance required to effect wedging of the fastening device
between the
two components in accordance with the preferred arrangement of the present
invention,
may typically be withir_ the range of 5 psi to 1,000 psi. The distance of
travel of the
pistons to effect wedging would be typically of the order of 10-12 mm, but
could be
between 5 and SO mm. Obviously, the pressure and distance travelled will vary
depending upon the particular application of the invention.
When the fastening device 26 is to be released, for example, when the
implement
attached to the bucket is to be removed for replacement, the grease nipple may
be rotated
such that the pressure within the fluid conduit is reduced enabling the
pistons 40 and 41
to be retracted to within the cavities 36 and 37. Thereafter, the embodiment
26 is able
to be released from the cavities or orifices.
The present invention has the advantage of reduced weight compared to the
prior
art devices and ease of insertion and release from its work sites. The
physical effort
required to remove the spool and wedge assembly is dramatically reduced and
little or no
sledge hammering is required. A large mechanical advantage is obtained in use
of the
hydraulic assembly to induce the friction forces in the recess rather than
relying on the
strength of a sledge hammer blow to achieve the same friction effect as was
the case with
the prior art.
It will of course be recognised by persons skilled in the art that numerous
variations and modifications may be made to the invention. For example, whilst
the
present invention has been particularly described in relation to a particular
fastening
arrangement useful for attaching wear teeth to an earth moving bucket, the
device may
be equally as well used for fastening any other two components together, from
domestic
household commercial use, etc. For example, wherever substantially aligned
holes are
WO 96/08612 PCT/AU94/00555
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drilled or otherwise supplied in two components, and those components are
intended to
be fastened together, the fastening device may be used. It will be appreciated
that a
particular advantage of the fastening device of the present invention is that
the provision
of compression or additional fluid material to the device is easily supplied
by known
means, and likewise pressure or additional fluid may be released from the
device by
likewise known devices.
The utilisation of a hydraulic mechanism eliminates disadvantages with known
mechanical fastening methods and devices. There is often a relationship
between the
physical strength of the person supplying the mechanical fastening device into
position
Obviously also, the shape and configuration of the device will obviously be
able to be
varied to a large extent. The number, sire and shape of the protrusions may
also vary
to a large extent.
Accordingly, it will be appreciated to persons skilled in the art that
numerous
variations and modifications to the invention will become apparent. All such
variations
1 S and modifications should be considered to fall within the scope of the
invention as
broadly described hereinbefore and as claimed hereinafter.
