Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR PUSHING ITEMS RELATIVE TO A SURFACE
Field of the Invention
This invention relates to an apparatus for pushing items relative to a
surface, and
more particularly, but not exclusively, to an articulated pushing apparatus
for pushing
items from a conveyor.
Background of the Invention
It is known to provide a push off diverter for pushing objects off a conveyer.
An
example push off diverter is pneumatically operated to move forward and
backward across
a conveyor for pushing objects from the conveyor or for transferring objects
from one
conveyor to another conveyor.
However, previously proposed push off diverters of the above type may slow
progress of objects along the conveyor by blocking passage of objects on the
conveyor
when the push off diverter is not fully retracted. Furthermore, abrupt
operation of the push
off diverter may cause damage to objects being pushed from the conveyor, and
may lead to
improper placement of the objects once transferred from the conveyor.
Examples of the present invention seek to provide an improved apparatus for
pushing items from a conveyor.
Summary of the Invention
In accordance with one aspect of the present invention, there is provided an
apparatus for pushing items relative to a surface, the apparatus including a
pushing
member for engaging the items, and drive means for moving the pushing member
such that
in response to operation of the drive means the pushing member moves from a
rest position
to an extended position in a first stroke substantially horizontally in a
direction across the
surface so as to push the items relative to the surface, and with further
operation of the
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drive means the pushing member returns to the rest position in a second stroke
with an
arcuate motion which clears items on the surface.
Preferably, the surface is a conveyor, and the first stroke is in a direction
transverse
to the conveyor. More preferably the apparatus includes a linkage coupling the
drive
means to the pushing member, and the linkage is arranged to provide movement
of the
pushing member in said first and second strokes in response to operation of
the drive
means.
Preferably, the drive means is a rotational member. More preferably, the
linkage is
arranged such that with constant rotational velocity of the rotational member
the pushing
member accelerates then decelerates along the first stroke, and with
continuous rotation of
the rotational member the pushing member repeatedly cycles through the first
and second
strokes. Even more preferably, the rotational member is driven by a motor and
rotates
about an axis which is fixed in relation to a support of the conveyor.
In a preferred form, the rotational member includes a driving arm, and the
linkage
includes:
a link pivotally coupled between the driving arm and the pushing member;
an elongated arm pivotally coupled between the link and a pivot fixed in
position
relative to the support of the conveyor, the elongated arm being arranged to
oscillate about the pivot in response to continuous rotation of the rotational
member; and
a tie member pivotally coupled between the elongated arm and the pushing
member;
wherein dimensions of the link, the elongated arm and the tie member, and the
locations of
the pivots, are selected to provide said motion of the pushing member along
the first and
second strokes.
Preferably, the arcuate motion is generally parabolic.
Preferably, the arcuate motion enables the pushing member to clear incoming
items
on the conveyor when returning to the rest position through the second stroke.
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In accordance with another aspect of the present invention, there is provided
an
apparatus for pushing items relative to a surface, the apparatus including a
pushing
member for engaging the items, and drive means for moving the pushing member
such that
in response to operation of the drive means the pushing member moves from a
rest position
to an extended position in a first stroke substantially horizontally in a
direction across the
surface so as to push the items relative to the surface, the pushing member
accelerating
then decelerating along the first stroke, and wherein with further operation
of the drive
means the pushing member returns to the rest position in a second stroke.
Preferably, the surface is a conveyor, and the first stroke is in a direction
transverse
to the conveyor. More preferably, the apparatus includes a linkage coupling
the drive
means to the pushing member, and the linkage is arranged to provide movement
of the
pushing member in said first and second strokes in response to operation of
the drive
means.
Preferably, the drive means is a rotational member. More preferably, the
linkage is
arranged such that with constant rotational velocity of the rotational member
the pushing
member accelerates during a start portion of the first stroke and then
decelerates during an
end portion of the first stroke. Even more preferably, the linkage is arranged
such that
with continuous rotation of the rotational member the pushing member
repeatedly cycles
through the first and second strokes. More preferably still, the linkage is
arranged such
that the rotational member is beyond a dead centre position when the pushing
member is in
the rest position. In a preferred example, the rotational member is driven by
a motor and
rotates about an axis which is fixed in relation to a support of the conveyor.
In one form, the rotational member includes a driving arm, and the linkage
includes:
a link pivotally coupled between the driving arm and the pushing member;
an elongated arm pivotally coupled between the link and a pivot fixed in
position
relative to the support of the conveyor, the elongated arm being arranged to
oscillate about the pivot in response to continuous rotation of the rotational
member; and
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a tie member pivotally coupled between the elongated arm and the pushing
member;
wherein dimensions of the link, the elongated arm and the tie member, and the
locations of
the pivots, are selected to provide the acceleration then deceleration of the
pushing
member along the first stroke.
Brief Description of the Drawings
The invention is described by way of non-limiting example only, with reference
to
the accompanying drawings in which:
Figure 1 is a perspective view of an apparatus for pushing items relative to a
conveyor;
Figure 2A is a top view of the apparatus, shown in a rest position;
Figure 2B is a side view of the apparatus, also shown in the rest position;
Figure 3A is a top view of the apparatus, shown in an extended position;
Figure 3B is a side view of the apparatus, also shown in the extended
position;
Figure 4 is a side view of a portion of the apparatus, showing movement
through a
first stroke;
Figure 5 is a side view of the same portion of the apparatus shown in Figure
4,
depicting movement through a second stroke;
Figure 6 is a partly exploded perspective view of the apparatus;
Figure 7 is a simplified diagram representing basic linkages of the apparatus
shown
in Figures 1 to 6.
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Detailed Description
With reference to Figure 1 there is shown an apparatus 10 for pushing items 12
relative to a conveyor 14. The apparatus 10 is shown in solid lines in a rest
position, which
the apparatus 10 adopts prior to pushing the items 12 from the conveyor 14,
and is shown
in broken lines in an extended position, which is adopted by the apparatus 10
after pushing
the items 12 from the conveyor 14.
The apparatus 10 includes a pushing member 16 which is used for abutting
against
the items 12 so as to push the items 12 in a direction generally transverse to
the conveyor
14. Although the direction generally transverse to the conveyor 14 as depicted
in the
drawings is substantially perpendicular to the direction of the conveyor 14,
it will be
understood by those skilled in the art that in other examples the direction
generally
transverse to the conveyor 14 may not necessarily be perpendicular to the
direction of the
conveyor 14. The apparatus 10 also includes drive means in the form of a
rotational
member 18, which itself is driven by a motor 20 via a belt 22. The rotational
member 18 is
coupled to the pushing member 16 via a linkage 26 through which the pushing
member 16
is driven by the rotational member 18.
The linkage 26 is arranged such that in response to operation of the motor 20,
the
pushing member 16 moves from the rest position to the extended position in a
first stroke
substantially horizontally in the direction transverse to the conveyor 14, so
as to push the
items 12 relative to the conveyor 14. In response to further operation of the
motor 20, the
pushing member 16 is returned to the rest position through a second stroke
with an arcuate
motion for passing over the top of items on the conveyor 14.
With reference to Figure 2A, the apparatus 10 is shown in the rest position in
which
the pushing member 16 is retained clear of the conveyor 14. The conveyor 14
and the
items 12 are shown in broken lines so as to show the motor 20 beneath the
conveyor 14.
Figure 2B shows the apparatus 10 in the same rest position depicted in Figure
2A,
and also depicts in broken lines subsequent positions of the apparatus 10
progressively at
intervals during the first stroke. The linkage 26 is arranged such that with
constant
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rotational velocity of the rotational member 18 the pushing member accelerates
during an
initial part of the first stroke, then decelerates during a final part of the
first stroke. Also,
with continuous rotation of the rotational member 18, the pushing member 16
repeatedly
cycles through the first and second strokes. Where items 12 are constantly
being fed along
the conveyor 14, it may be desirable to run the motor 20 continuously so as to
continuously
cycle the apparatus 10 through the first and second strokes so as to push the
items 12 from
the conveyor 14 as quickly as possible. Alternatively, in the case where there
are intervals
between the items 12 arriving in front of the pushing member 16, it may be
desirable to
pause the motor 20 to hold the apparatus 10 in the rest position to await a
full complement
of items 12 in front of the pushing member 16 prior to operating the apparatus
10 through
its cycle of the first and second strokes. As will be appreciated from the
view shown in
Figure 2B, the rotational member 18 rotates about an axis 28 which is fixed in
relation to a
support of the conveyor 14. More particularly, in the case where the support
of the
conveyor 14 is in the form of a stationary frame structure as is commonly the
case, the axis
28 about which the rotational member 18 rotates is also stationary.
As shown in Figure 2B, the linkage 26 is arranged such that the rotational
member
18 is rotated beyond a horizontal dead centre position when the pushing member
16 is in
the rest position. Advantageously, this results in beginning the first stroke
when there is a
non-zero horizontal component to the instantaneous direction of movement of a
driving
arm 36 of the rotational member 18, as well as when the pushing member 16 has
been fully
lowered with a pushing surface of the pushing member 16 in a substantially
vertical
orientation. In that regard, the apparatus 10 in the example shown is
configured such that
at the beginning of the second stroke lowering of the driving arm 36 from an
opposed
horizontal dead centre position results in upward movement of the pushing
member 16
away from the level of the surface of the conveyor. Similarly, at the end of
the second
stroke after rotation of approximately 180 degrees, raising of the driving arm
36 to the
horizontal dead centre position results in lowering of the pushing member 16
to the surface
of the conveyor 14.
With reference to Figure 3A, the top view of the apparatus 10 shows the
arrangement of the linkage 26 when the pushing member 16 is in the extended
position
between the first and second strokes, after pushing the items 12 from the
conveyor 14.
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Figure 3B shows a side view of the apparatus 10 in the extended position in
solid lines, and
also shows (in broken lines) the configuration of the apparatus 10 at
subsequent stages
during the second stroke wherein the pushing member 16 is returned to the rest
position.
Figures 4 and 5 depict the linkage 26 and pushing member 16 of the apparatus
10.
More particularly, Figure 4 shows in said lines the linkage 26 and pushing
member 16 in
the rest position, as well as subsequent configurations of the linkage 26 and
the pushing
member 16 during the first stroke (in broken lines). Arrow 30 illustrates the
substantially
horizontal movement of the pushing member 16 during the first stroke which
facilitates
successful transfer of the items 12 from the conveyor 14. Similarly, Figure 5
shows the
linkage 26 and pushing member 16 in solid lines in the extended position, as
well as
subsequent configurations of the linkage 26 and pushing member 16 during the
second
stroke (in broken lines). Arrow 32 illustrates the arcuate motion of a lower
edge 34 of the
pushing member 16 during the second stroke.
With reference to the partially exploded perspective view of the apparatus 10
shown in Figure 6, the rotational member 18 includes the driving arm 36, and
the linkage
26 includes a link 38, an elongated arm 40, and a tie member 42 which couple
the pushing
member 16 to the driving arm 36. More specifically, the link 38 is pivotally
coupled at
each end between the driving arm 36 and the pushing member 16, the elongated
arm 40 is
pivotally coupled at each end between the link 38 and a pivot 44 which is
fixed in position
relative to the support of the conveyor 14, and the tie member 42 is pivotally
coupled at
each end between the elongated arm 40 and the pushing member 16.
Figure 7 provides a simple diagrammatic side view of the rotational member 18,
driving arm 24, link 38, elongated arm 40, tie member 42, and pushing member
16, which
facilitates an understanding of the motion of these components through the
first and second
strokes. The elongated arm 40, which incorporates a substantially right-angled
bend at
location 46 to facilitate movement of the pushing member 16 over the conveyor
14,
oscillates about the pivot 44 in response to continuous rotation of the
rotational member
18. As will be appreciated, acceleration of the pushing member 16 in an
initial part of the
first stroke, and deceleration of the pushing member 16 in a final part of the
first stroke,
facilitate successful transfer of the items 12 from the conveyor 14 by
avoiding damage to
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the items 12 through abrupt movement, as well as by encouraging correct
location of the
items 12 when deposited from the conveyor 14 by avoiding overshoot.
Advantageously,
this promotes delivery of undamaged products, as well as smooth subsequent
processing of
the items 12 by avoiding incorrect location of the items 12 when transferred.
Advantageously, the arcuate motion of the pushing member 16 during the second
stroke enables the pushing member to pass over the top of incoming items on
the conveyor
14, thus speeding up processing of the items by allowing the items to arrive
in place (ie. for
pushing by the apparatus 10) during the previous cycle of motion of the
apparatus 10.
Although the arcuate motion depicted in the example shown in the drawings is
generally
parabolic, it will be appreciated by those skilled in the art that other
arcuate motion of the
pushing member 16 may be used in alternative examples.
The above apparatus 10 has been described by way of example only and
modifications are possible within the scope of the invention. In one
alternative example,
the acceleration of the pushing member during the initial part of the first
stroke and the
deceleration of the pushing member 16 during the final part of the first
stroke are retained,
but the pushing member 16 has substantially horizontal motion during the
second stroke
(rather than the arcuate motion of the example described above). Even without
the arcuate
motion in the second stroke, this alternative example is advantageous due to
the
acceleration and deceleration of the pushing member 16 facilitating accurate
delivery of
undamaged items, by way of gentle movement of the items.
Examples of the invention may be used to push items from one surface to
another
surface, whether or not one or both of the surfaces is/are of a conveyor or
conveyors. An
apparatus in accordance with an example of the invention may also be used to
push items
from one position on a surface to another position on the same surface.
The reference in this specification to any prior publication (or information
derived
from it), or to any matter which is known, is not, and should not be taken as
an
acknowledgment or admission or any form of suggestion that that prior
publication (or
information derived from it) or known matter forms part of the common general
knowledge in the field of endeavour to which this specification relates.
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Throughout this specification and the claims which follow, unless the context
requires otherwise, the word "comprise", and variations such as "comprises"
and
"comprising", 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.
