Note: Descriptions are shown in the official language in which they were submitted.
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PIVOTING IMPLEMENTS AND ADJUSTMENT ARRANGEMENTS FOR EARTH
MOVING OR MATERIALS HANDLING MACHINES
FIELD OF THE INVENTION
The invention relates to pivoting implements for attachment to earth moving or
materials
handling machines.
BACKGROUND TO THE INVENTION
Earth moving or materials handling machines can be adapted for and/or used in
various
applications including construction, earthworks, demolition, forestry, -
drainage,
quarrying, mining etc. Implements are attached to the machine, for example to
the arm
of an excavator. Implements include buckets, rippers, ploughs, rakes, spades
and
rollers.
Some excavator buckets are capable of adjustable pivoting with respect to the
machine.
This is generally achieved using a pivot between the main body of the bucket
and a
coupling part of the bucket. The bucket may be connected to an excavator by
the
coupling part. One or two hydraulic cylinders are connected to the bucket and
to the
coupling part and drive rotation of the bucket with respect to the coupling
part. The
coupling part remains fixed with respect to the excavator.
Due to the pivoting motion of the bucket, the cylinders must be attached so as
to .pivot
freely around their attachment points at each end. In general, pivoting
connections are
provided at each end of each cylinder. These are common failure points, since
adjustment creates wear in the connection and also because lateral loads
imposed on
the bucket during use are transmitted through these connections.
It is an object of the invention to provide an improved pivoting mechanism
and/or an
improved pivoting implement for an earth moving or materials handling machine,
or at
least to provide the public with a useful choice.
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SUMMARY OF THE INVENTION
In a first broad aspect the invention provides an implement configured for
adjustable
pivoting with respect to an earth moving or materials handling machine to
which the
implement is, in use, attached, including:
an implement body;
a coupling section for attachment of the implement to an earth movingSr-
materials
handling machine;
a linear actuator operating along an axis which is substantially fixed
relative to an
attachment point of the actuator;
an engagement element configured to be driven by the linear actuator; and
a rotator element configured to engage with the engagement element such that
motion
of the engagement element drives rotational motion of the implement body
relative to
the coupling section.
Preferably the linear actuator is a hydraulic ram.
Preferably the implement includes two linear actuators operating along the
axis and
driving the engagement element.
Preferably the engagement element is connected to the linear actuator.
Preferably the
linear actuator is a hydraulic ram and the engagement element is connected to
the rod
of the ram.
Preferably the engagement element and the rotator element - are formed with
cooperating teeth.
Preferably the engagement element is a rack. Preferably the rotator element is
a
pinion.
Preferably the rotator element is mounted to the coupling section.
Preferably the linear actuator is mounted to the body of the implement.
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Preferably the implement is configured to provide lateral pivoting of the body
of the
implement.
Preferably the implement includes a cover to substantially enclose the linear
actuator,
engagement element and rotator element.
In a second broad aspect the invention provides an adjustment mechanism for
pivoting
an implement with respect to an earth moving or materials handling machine to
which
the implement is, in use, attached, the implement including an implement body
and a
coupling section, the adjustment mechanism including:
a linear actuator operating along an axis which is substantially fixed
relative to an
attachment point of the actuator;
an engagement element configured to be driven by the linear actuator; and
a rotator element configured to engage with the engagement element such that
motion
of the linear actuator drives rotational motion of the implement body.
Preferably the linear actuator is a hydraulic ram.
Preferably the mechanism includes two linear actuators operating along the
axis and
driving the engagement element.
Preferably the engagement element is connected to the linear actuator.
Preferably the
linear actuator is a hydraulic ram and the engagement element is connected to
the rod
of the ram.
Preferably the engagement element and the rotator element are formed with
cooperating teeth.
Preferably the engagement element is a rack. Preferably the rotator element is
a
pinion.
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Preferably the rotator element is configured for mounting to an implement's
coupling
section.
Preferably the linear actuator is configured for mounting to the body of an
implement.
Preferably the adjustment mechanism is configured to be positioned between an
implement's body and coupling section.
Preferably the mechanism is configured to provide lateral pivoting of the body
of the
implement.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example only, with reference to
the
accompanying drawings, in which:
Figure 1 is a perspective view of an implement according to one embodiment;
Figure 2 is a second perspective view of the implement of Figure 1;
Figure 3 is an exploded view of the adjustment mechanism of the implement of
Figure 1;
Figure 4 is a side view of the assembled adjustment mechanism of Figure 3;
Figure 5 is an exploded view of the top plate, rotator element and shaft
assembly
of the implement of Figure 1;
Figure 5A is a cross-section through the top plate, rotator element and shaft
assembly of Figure 5;
Figure 6 is a cross-section along the line 6-6 in Figure 4;
Figure 7 is a schematic force diagram showing forces acting in the implement
of
Figure 1; and
Figure 8 is a schematic force diagram showing forces acting in a prior art
implement.
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DETAILED DESCRIPTtON
Figures 1 and 2 are perspective views of an implement 1 including an
adjustment
mechanism 2. The implement shown is a bucket suitable for attachment to an
5 excavator, but the invention may be applied to other implements for use with
any
suitable earth moving or materials handling machines.
Implements indude buckets, rippers, ploughs, rakes, spades, rollers or any
other
implements for attachment to earth moving or materials handling machines.
Earth moving or materials handling machines can be adapted for and/or used in
various
applications induding construction, earthworks, demolition, forestry,
drainage,
quarrying, mining etc. The term "earth moving or materials handling machine"
includes
machines used in these and other applications. In particular, earth moving
=and
materials handling machines include excavators and telehandlers.
A coupling section 3 allows connection of the implement I to an excavator arm
or quick
hitch arrangement, or to another earth moving or materials handling machine,
as will be
understood by a skilled reader.
The adjustment mechanism 2 allows the body 4 of the implement 1 to pivot
laterally
with respect to the coupling section 3, and therefore with respect to a
machine to which
the implement is, in use, attached.
Figure 3 is an exploded view showing some components of the adjustment
mechanism.
The adjustment mechanism includes a top plate 10 to which the coupling section
3 may
be attached. A rotator element 11 and a shaft 12 are mounted to the uriderside
of the
top plate 10. The shaft 12 includes a central bore 13 which receives a pin 14,
such that
the pin 14 can rotate with respect to the shaft 12, rotator element 11 and top
plate 10.
The pin 14 is supported and connected at each end to the body 4 of the
implement 1 as
follows. A front plate is formed from a front plate main bearer 16 and a front
plate
laminate 17. A back plate is formed from a back plate bearer 18 and a back
plate
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laminate 19. Both the front plate and the back plate are connected, preferably
welded,
to the body 4 of the implement I as is clear from Figures 1 and 2.
The back plate and the front plate each include a bore 21, 22 dimensioned to
receive
the main shaft of the pin 14. These bores may be formed after the back and
front
plates have been connected to the implement body 4. The pin includes a flange
24 at
one end and a head 25 at the other end. The head is configured for attachment
to the
pin after the pin has been inserted through the bores 21, 22 of the front and
back plates
and the bore 13 of the shaft 12.
Figure 4 is a side view of the adjustment mechanism 2. This view shows the
assembled positions of the various components. A base plate 30 is connected
between
the front plate bearer 16 and the back plate bearer 18, with the front and
back plate
laminates 17, 19 sitting on top of the base plate 30. The base plate provides
structure
and facilitates connection of one or more linear actuators, as will become
apparent
below. The base plate also prevents contamination of the adjustment mechanism
from
material (e.g. soil) carried in the body 4 of the bucket.
Figure 4 also shows how the top plate 10 is supported on the shaft 12 by the
rotator
element 11 and a support element 31.
Figure 5 is an exploded view of the top plate 10, rotator element 11 and shaft
12
assembly. The shaft 12 includes a pair of bosses 32, 33. The first boss 32
engages
with a bore 34 in the rotator element 11, while the second boss 33 engages
with the
shaped lower edge 35 of the support element 31. A spacer 36 sits between the
two
bosses 32, 33 while one or more bushes 37 sit inside the bores 38 of the
bosses 32,
33. In turn the pin 14 (Figure 3) sits within the bore 13 formed by the
internal surfaces
of the bushes 37. The bushes therefore serve to reduce friction caused by
rotational
movement of the pin 14 with respect to the shaft 12.
Figure 5A shows a cross-section along the length of the assembled top plate
10, rotator
element 11 and shaft 12 assembly.
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Thus, the pin 14, which is fixed to the body 4 of the implement 1, is free to
rotate within
the shaft 12.
Returning to Figure 3, the adjustment mechanism 2 also includes an engagement
element 40 which engages with the rotator element 11. The engagement element
40
and the rotator element 11 may be cooperating gears, formed with cooperating
teeth.
In the embodiment shown, the engagement element 40 and the rotator element 11
form
a rack and pinion mechanism, such that linear motion of the engagement element
40
relative to the body 4 of the implement 1 drives rotational motion of the
implement-body
4 about the rotator element 11.
The engagement element 40 is itself driven by one or more linear actuators 41
(Figure
1). The actuators may be hydraulic cylinders. For large implements which are
both
heavy and designed to carry heavy loads, two hydraulic cylinders may be
preferred as
shown in Figures 1 and 2. For smaller implements or those where smaller loads
are
expected a single hydraulic cylinder may be sufficient.
The hydraulic cylinders 41 may reside in a shaped recess 42 in the base plate
30. This
means that the rod 44 of each hydraulic cylinder 41 is positioned at an
appropriate
height to drive motion of the engagement element 40, as will be described
below.
A cylinder bracket 45 is provided at each side of the adjustment mechanism.
The
brackets 45 may be shaped to fit the recess 42 in the base plate 30 and may be
welded
to the base plate 42 as shown in Figure 4.
The casing of each hydraulic cylinder 41 is connected to a cylinder bracket
45. Since
the motion of the cylinder rod 44 is substantially linear, there is no need
for the cylinder
to rotate at the connection to the bracket 45. This can therefore be a simple,
fixed
connection.
Thus the linear actuator operates along an axis which is substantially fixed
relative to
the body 4 of the implement 1, and therefore relative to the connection point
where the
linear actuator is connected to the body 4. Here, "substantially fixed" means
that the
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axis is sufficiently independent of the degree of extension of the linear
actuator that no
rotating connection between the linear actuator and the body 4 of the
implement 1 is
required.
The rod 44 of each hydraulic cylinder 41 is connected at its distal end to a
connector
47. The connector 47 is fixed to the engagement element 40 by appropriate
fasteners.
Thus the hydraulic cylinders 41 operate to drive the connector 47 and
engagement
element 40 in linear motion relative to the body 4 of the bucket 1, from side
to side
across the bucket 1. The engagement element therefore moves parallel to the
axis of
the hydraulic cylinders 41.
Figure 6 is a cross-section along the line 6-6 in Figure 4. This shows the
hydraulic
cylinders 41 and the connection of the rods 44 to the connector 47. The teeth
49 of the
engagement element 40 engage with the teeth 50 of the rotator element 11.
Thus,
linear motion from the hydraulic cylinders is transmitted via the connector 47
and
engagement element 40 to drive rotational motion of the body 4 of the
implement 1
relative to the rotator element 11.
Figure 7 is a schematic force diagram of the Applicant's mechanism. One end of
a
linear actuator (not shown) is connected to the implement body at point 70.
The
implement body rotates about a pivot point 72. The linear actuator (either
extending or
retracting) always acts to apply a force along an axis (indicated by arrow 73)
which is
tangential to the circumference of the rotator element 71. Therefore,
irrespective of the
pivot angle of the implement, the radius r from the pivot point 72 to the
force vector 73
remains the same. Therefore, maximum torque is available irrespective of pivot
angle.
Where two hydraulic cylinders are used, both will act along the same axis
tangential to
the circumference of the rotator element 71.
Figure 8 is a schematic force diagram of a prior art mechanism. One end of a
hydraulic
cylinder is connected to the bucket body 79 at point 80. A second hydraulic
cylinder is
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connected to the bucket body 79 at point 81. The bucket body is configured to
rotate
about a point 82. The other end of each hydraulic cylinder is connected at
point 83.
The hydraulic cylinders therefore exert forces in the directions indicated by
the arrows
84, 85. The radii r', r" from the pivot point 82 to the force vectors 84, 85
are dependent
on the pivot angle and are significantly reduced for large pivot angles.
Therefore, at
large pivot angles larger forces are required to achieve the same torque.
Therefore, the Applicant's mechanism provides even torque over the entire
pivot range.
This means that a less powerful linear actuator, or a smaller number of
actuators, can
be used or that better performance can be obtained over the entire pivot range
for a
given size of actuator than in prior mechanisms.
In the Applicant's mechanism, linear actuators do not rotate around their end
connections. This reduces the number of parts since, for example, bushes are
not
required at these connections. Furthermore, this reduces wear and improves
reliability.
An alternative embodiment may have the rotator element fixed to the body 4 of
the
implement 1, while the linear actuators are fixed relative to the coupling
section 3.
While the present invention has been illustrated by the description of the
embodiments
thereof, and while the embodiments have been described in detail, it is not
the intention
of the Applicant to restrict or in any way limit the scope of the appended
claims to such
detail. Additional advantages and modifications will readily appear to those
skilled in
the art. Therefore, the invention in its broader aspects is not limited to the
specific
details, representative apparatus and methods, and illustrative examples shown
and
described. Accordingly, departures may be made from such details without
departure
from the spirit or scope of the Applicant's general inventive concept.
