Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
THIS invention relates to ground engaging tools, and in particular to an
assembly of ground engaging tool components.
A large proportion of the machinery used in earth moving operations utilise
buckets. The teeth attached to the lips of such buckets are generally subj ect
to considerable wear and it is therefore necessary to replace these teeth, or
at least portions of them, periodically.
For this reason a number of methods have been developed for releasably
attaching ground engaging teeth to the lips of buckets of various earth
moving machinery. In some of these methods a series of nosepieces are
connected to the lip of a bucket, side by side, and an adaptor is used to
releasably connect a tip to each nosepiece. A shroud may also be attached
to adjacent nosepieces to provide a wear surface between successive teeth,
if desired.
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SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a method of
connecting together two ground engaging tool components, the method
comprising the steps of:
providing on one of the components a spigot having two opposed
tapered faces which are spaced apart from one another by two side
faces;
forming a groove on at least one of the side faces, the opposed side
walls of the groove being tapered in an opposite sense to the taper on
the opposed tapered faces;
forming in the second component a socket having opposed internal
tapered faces corresponding to the opposed tapered faces on the
spigot, the internal tapered faces of the socket being spaced apart by
two internal side faces corresponding to the side faces of the spigot;
providing a wedge on at least one of the internal side faces of the
socket, the opposed side walls of the wedge being tapered in an
opposite sense to the taper on the opposed internal tapered faces of
the socket so as to correspond to the taper on the opposed side walls
of the groove;
fitting the spigot of the first component into the socket of the second
component so that the wedge on the second component lies within
the groove of the first component and is movable along the length of
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the groove so that it can be wedged therein when the two opposed
tapered faces on the spigot mate with the two opposed internal
tapered faces in the socket; and
providing holding means on the components for holding them
together until a working load is applied to the components and the
wedge is driven along the groove so as to become wedged therein,
thereby firmly securing the two components together.
Preferably, the step of providing holding means on the components
comprises passing a locking pin through aligned apertures on the two
components to secure the components together until a working load is
applied to the components.
According to a second aspect of the invention there is provided an assembly
of ground engaging tool components comprising:
a first component having a spigot which defines two opposed tapered
faces and a pair of side faces spacing the tapered faces from one
another, at least one of the side faces of the spigot defining a groove
with opposed side walls which are tapered in an opposite sense to the
taper on the opposed tapered faces;
a second component defining a socket having opposed internal
tapered faces which correspond to the tapered faces on the spigot,
and a pair of internal side faces spacing the internal tapered faces
from one another, at least one of the internal side faces including a
wedge having opposed side walls which are tapered in an opposite
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sense to the taper on the opposed internal tapered faces of the socket
and which correspond to the taper on the opposed side walls of the
groove, the spigot on the first component being arranged to fit within
the socket in the second component so that the wedge on the second
component lies within the groove of the first component and is
movable along the length of the groove so that it can be wedged
therein when tile two opposed tapered faces on the spigot mate with
the two opposed internal tapered faces in the socket; and
holding means on the components for holding them together until a
working load is applied to the components and the wedge is driven
along the groove so as to become wedged therein, thereby firmly
securing the two components together.
The assembly of ground engaging tool components may be a tooth assembly
connectable to the lip of a bucket of an earth moving machine.
Conveniently, the side faces of the spigot and the internal side faces of the
socket are also tapered.
Preferably, the holding means is a locking pin arranged to pass through
alignable apertures in the two components to secure the components together
until the working load is applied to the components.
The pin may include a shank and a non-symmetrically shaped resilient head
which extends laterally from the shank. In this case the aperture in the
second component is sized and shaped to allow the enlarged head of the pin
to pass therethrough, while the aperture in the first component is sized and
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shaped to allow only the shank, and not the head, of the pin to pass
therethrough. In this way, once the locking pin has been passed through the
apertures so that the head bears against the spigot, the locking pin can be
rotated with respect to the components so that the non-symmetrically shaped
head is rotated into a recess in the side wall of the aperture in the second
component to thereby lock the two components together.
The recess in the side wall of the aperture in the second component may
include a node at one end so that a predetermined torque is required to turn
the head into the recess. In this case, the recess may be sized so that the
resilient head is captured and held in compression within the recess.
Conveniently, the components are formed from steel. The components may
also include tungsten steel inclusions.
Preferably, the shank of the locking pin is formed from steel and the
resilient
head is formed from a high density polyurethane compound.
The invention further provides for a locking pin for locking together two
ground engaging tool components, the locking pin comprising:
a generally elongate shank;
a non-symmetrically shaped head which extends laterally from the
shank, the head being sized and shaped to pass through an aperture
in one of the components but not through an aperture in the other of
the components; and
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a formation on the pin for engaging a rotatable member so that the
head can be rotated into a recess on a portion of the side wall of the
aperture through which the head can pass.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail, by way of example
only, with reference to the accompanying drawings in which:
Figure 1 shows a front perspective view of a tooth assembly according
to the invention;
Figure 2 shows a front perspective view of a nosepiece according to
the invention;
Figure 3 shows a rear perspective view of an adaptor according to the
invention;
Figure 4 shows a front perspective view of the adaptor of Figure 3;
Figure 5 shows a rear perspective view of a tip according to the
invention;
Figure 6 shows a front perspective view of the tip of Figure 5;
Figure 7 shows a side view of the tip of Figure 5;
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Figure 8 shows a top plan view of a locking pin according to the
invention;
Figure 9 shows a front view of the locking pin of Figure 8; and
Figure 10 shows a perspective view of the locking pin of Figure 8.
DESCRIPTION OF A PREFERRED EMBODIMENT
Figure 1 shows a perspective view of ground engaging tool components in
the form of a tooth assembly 10 which is connectable to the lip of a bucket
(not illustrated) of an earth moving machine. Typically, a series of such
assemblies are arranged side by side on the lip of the bucket to provide a
plurality of spaced apart teeth on the bucket.
The tooth assembly 10 comprises a nosepiece 12, an adaptor 14 releasably
connected to the nosepiece, and a tip 16 releasably connected to the adaptor.
Referring to Figure 2 of the drawings, the nosepiece 12 has a front face 20
and upper and lower faces 22 and 24 extending back from the front face to
form a shallow U-shaped formation which defines a channel 26. The channel
26 is sized to fit over the lip of a conventional bucket for earth moving
machinery. A central rib 28 projects outwardly from the upper and lower
faces 22 and 24, and forwardly from the front face 20, as shown. The rib 28
includes a spigot 30 which also projects forwardly.
The spigot 30 has two side faces 32 and 34, a bottom face 36 and a top face
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3 8 which a11 taper inwardly towards the free end 40 of the spigot. A tapered
groove 42 extends rearwardly from the free end 40 along each of the side
faces 32 and 34. The grooves 42 have side walls 46 and 48 which converge
towards one another as they move away from the free end 40 of the spigot.
The bottom face 36 of the spigot 30 defines a generally circular aperture
(not shown) for receiving a locking pin (also not shown).
Figures 3 and 4 illustrate the adaptor 14 which is connectable to the
nosepiece 12. The adaptor 14 is in the form of a hollow, steel, generally
wedge-shaped body which has four sides 52, 54, 56 and 58. The four sides
converge towards one end 59 of the adaptor. On the inside of each of the
sides 54 and 58 there is a wedge 60 which is shaped to engage with the
groove 42 on the nosepiece 12. Accordingly, the side walls of the wedges
60 converge complementally to the side walls of the grooves 42.
The side 56 of the adaptor 14 defines an aperture 62 for receiving a non-
symmetrical head of a locking pin (not shown). The shape of the aperture
will be described in more detail below.
An adaptor spigot 64 projects from the end 59 of the adaptor 14. The
adaptor spigot is similar in shape to the nosepiece spigot 30 and also has
sides which taper towards the free end 66 thereof. Also similarly to the
nosepiece spigot, the adaptor spigot 64 has a pair of tapered grooves 68
which are formed on the sides 70 and 72 of the spigot. Unlike the nosepiece
spigot, however, the adaptor spigot defines a generally circular aperture 74
on each side 70 and 72, at the rearmost end of each groove 68.
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The tip 16 is illustrated in Figure 5 to 7 of the drawings and is also in the
form of a hollow, steel, substantially wedge-shaped body. In the case of the
tip, the steel may include tungsten steel inclusions to improve the wear
characteristics of the tip. The tip has four wear faces 80, 82, 84 and 86
which are designed to contact the earth and rubble being loaded into the
bucket. On the inside of the wear faces 82 and 86 a tapered wedge 88
extends in a similar fashion to the wedge 60 on the adaptor 14. Furthermore,
the wear faces 82 and 86 also define non-symmetrical apertures 90 for
receiving the non-symmetrical head of a locking pin (not shown).
In Figures 8 to 10 there is shown a locking pin 100 which has a steel,
circular cylindrical shank 102 and a non-symmetrical head 104 in the form
of a cam formed from a high density polyurethane compound having a Shore
hardness of between 80 and 90. The head l04 is cast integrally with the
shank 102. The locking pin l00 includes a recessed formation 106 which is
shaped to receive a key or the like so that the locking pin can be rotated.
Referring again to Figure 7 of the drawings, the apertures 90 are generally
oval or egg-shaped, as shown, to receive the heads 104 of locking pins 100.
Each aperture 90 includes a recessed portion l08 on a portion of the side
wall of the aperture remote from each wear face 82 and 86 into which the
head 104 can be turned. Accordingly, once the locking pin has been slid into
the wear face 82 and the head l04 has been turned into the recess 108 the
locking pin cannot be slid out of the wear face unless it is first rotated out
of the recess.
The recess 108 also includes a node 110 at the entrance thereto so that a
predetermined torque is required to rotate the head 104 into this recess. Once
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the head has been rotated into the recess, it is captured there by the node
110. The size of the recess is slightly smaller than that of the head so that
the resilient material of the head is compressed when it is captured in the
recess.
The shape of the aperture 62 is similar to that of the aperture 90, while the
shape of the apertures 74 in the spigot 64 and the aperture in the bottom face
36 of the spigot 30 are generally circular.
In use, the nosepiece 12 is connected to the lip of a bucket (not illustrated)
by a suitable means, such as by welding. Thereafter, the adaptor 14 is slid
onto the spigot 30 of the nosepiece 12 so that the wedges 60 lie within the
grooves 42 and the aperture 62 is aligned with the aperture on the bottom
face 36 of the spigot 30. The wedges and grooves are designed so that the
side walls of the wedges bear against the side walls of the grooves when the
tapered faces 32, 34, 36 and 38 mate with the tapered sides 52, 54, 56 and
58. In this position the aperture 62 in the adaptor is aligned with the
corresponding aperture in the nosepiece.
At this stage a locking pin (as illustrated in Figures 8 to 10 of the
drawings)
is fitted into the aligned apertures so that the shank 102 passes through both
apertures but the head 104 passes through the aperture 62 only and bears
against the bottom face 36. Thereafter the head of the locking pin 100 is
rotated, with the aid of a key or the like, into the recess of the aperture 62
so as to be captured in the recess for locking the adaptor 14 to the nosepiece
12. The adaptor 14 is then substantially fixed with respect to the nosepiece
12 by virtue of the relatively close tolerance fit between the adaptor and the
nosepiece. Furthermore, the adaptor 14 is wedged onto the nosepiece as a
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result of the compressive force on the resilient head of the locking pin l00
in the recess. However, although the interaction between the tapered wedges
60 and the tapered grooves 42 serves to resist creep between the mating
tapered faces of the adaptor 14 and the nosepiece 12, the adaptor is capable
of being forced slightly further onto the nosepiece when a working load is
applied to the components so as to be wedged more securely onto the
nosepiece.
Once the adaptor 14 has been locked to the nosepiece, the tip 16 is slid onto
the adaptor spigot 64 in a similar fashion to that described above with
respect to the adaptor and the nosepiece so that the wedges 88 on the tip lie
within the grooves 68 on the adaptor. Once again, the apertures 90 and 74
are aligned with one another when the side walls of the wedges 88 bear
against the side walls of the grooves 68.
A locking pin similar to that illustrated in Figures 8 to 10 is then inserted
into the apertures 90 and 74 as described above and the head of the locking
pin is rotated into the recess l08 so as to lock the tip 16 onto the adaptor
14.
The tip and adaptor are also capable of slight additional creep with respect
to one another under a working load until the two are wedged securely to
one another.
The locking pin serves mainly to initially secure the components together
until, under a working load, the components are securely seated upon one
another. In this way movement of one of the components relative to the
others is substantially eliminated and shock loading is considerably reduced.
When a series of adaptors and tips have been connected to a number of
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nosepieces on the lip of a bucket in the manner described above, a series of
spaced apart teeth are securely wedged to the lip of the bucket.
Since the side walls of the grooves and wedges taper in an opposite sense to
that of the opposed tapered faces of the spigots and sockets, the wedging
action for securing the components together is improved.
Although the invention has been described with particular reference to tooth
assemblies for attachment to the lips of buckets of earth moving machinery,
it should be appreciated that the invention is not limited to such tooth
assemblies and may also be applied in the connection of various other
ground engaging tool components.
