TIPPING ACTUATOR FOR A CONVEYOR SYSTEM
Field of Invention
The invention relates to tipping actuators for conveyor systems and improvements in such
devices and their ility.
Background to the Invention
Conveyors are often used in grading machines to transport articles through various
measurement stages and to discharge the articles to sort them dependent on the
measurements. Such conveyors usually include an endless chain or belt on which are mounted
a plurality of e carriers or cups. A discharge mechanism is used to unload s at certain
points along the or.
A common type of object that is graded and sorted by such a conveyor system is fruit. Fruit
may be sorted based on criteria such as weight, shape, colour, ripeness and any other
characteristic. Conveyor systems comprise devices to e these teristics while the
fruit is being transported. The position of each fruit and its tive characteristics can be
tracked so that a discharge mechanism causes items of fruit to be unloaded from the conveyor
and sent to the required destination, for example s a chute or onto r or.
The applicant’s own US patent no. 044 discloses an article carrier suitable to be mounted
to a conveyor and used to sort fruit in a sorting assembly. A carrier frame is pivotable between a
carriage position, in which fruit may be supported on the carrier frame, and a discharge position,
in which fruit may fall off the carrier frame under gravity and thereby be discharged from the
article carrier. The carrier frame has contact surfaces that may be ted by an actuator
when the carrier frame is in the carriage position to cause the carrier frame to tip into the
discharge position and cause a fruit on the carrier frame to be unloaded. Advantageously the
carrier frame can tip in both ys directions so that fruit can be discharged to either side.
A latch or locking member is engaged to the carrier frame and moveable between two positions
in order to lock the carrier frame in position or to unlock the carrier frame and thus allow it to
pivot on the article carrier.
In one version of an existing system, the actuator comprises a id which, when activated,
causes a pivotal trigger member to flick upwards before falling under gravity. Activation is timed
so that the trigger member impacts one of the contact surfaces of the locking member, causing
it to move to the unlocked position and r to transfer the impact to the carrier frame,
causing the r frame to tip. This mechanism requires a significant amount of energy to flick
the trigger upwards, which is transmitted to the latch which s the delatching mechanism
to pon transfer the force to the carrier frame . These series of impacts makes the
conveyor system very noisy, particularly where le tipping actuator mechanisms are
operating simultaneously. Furthermore, the impact can have a different effect on fruit of different
weights. Light fruit may be caused to jump off the article carrier rather than merely tipping off.
This can damage fruit and also may cause the fruit to fall or bounce somewhere other than is
intended. In contrast, the force of the impact may not be sufficient to tip the carrier frame at all if
it is carrying heavy fruit. Another drawback of the existing trigger mechanism is that there is a
narrow window of opportunity for the trigger to be activated and to impact the carrier frame
correctly. This increases the complexity in the control system and means errors in fruit
discharge can easily occur where the window is .
The tipping trigger ism on MAF’s Genesis conveyor system comprises a generally
ular-shaped trigger plate that has a default position laterally outside the article carriers on
the conveyor. The trigger can be moved inwardly where the upper surface of the plate comes
into contact with an e carrier, causing it to tip away from the trigger. The trigger is actuated
by a solenoid and a spring biases the trigger back to the default position once the solenoid is
de-activated. When used with light fruit, the trigger may cause the article carrier to tip violently,
and therefore risks the fruit bouncing off cally. Furthermore, the r is only able to
accommodate the carrier tipping away from the trigger, which reduces flexibility in the design of
the conveyor system. Another problem with the MAF system is that the spring mechanism to
return the trigger to the default position can wear out over the course of repeated use.
Object of the Invention
It is an object of the invention to provide an improved tipping actuator for a or system.
Alternatively, it is an object to provide an improved conveyor system. Alternatively, it is an object
of the invention to address one or more of the antages of prior tipping actuators and
conveyor systems, such as those described above. Alternatively, it is an object of the invention
to at least provide the public with a useful choice.
y of the Invention
Preferred aspects of the invention are set forth in the appended claims. Particular embodiments
are described below in non-limiting terms.
According to a first embodiment of the ion, there is provided a g actuator for a
conveyor , the conveyor system comprising a plurality of article carriers moving on an
endless or in a conveying direction, each article carrier having a carrier frame for bearing
an article, the carrier frame being pivotally mounted on the article carrier and operable to tip to
enable discharge of the article borne on the carrier frame, the tipping actuator comprising:
a trigger member having a contact portion for contacting the article carriers; and
an actuation ism le to move the trigger member between a non-contact
position, in which the contact portion is oned out of the path of the article carriers so as to
avoid contact therewith, and a contact position, in which the t portion is positioned in the
path of the article carriers to make contact ith and effect tipping thereof away from the
trigger member,
wherein the r member is configured such that, when in the non-contact position,
the article carriers are able to at least partly tip s the trigger member such that the contact
portion of the trigger member is received by a portion of the article carrier.
This allows for a compact conveyor system and means the trigger member moves only a small
distance between the contact and non-contact positions.
More preferably, the trigger member is configured such that, when in the non-contact position,
the article carriers are able to tip only partly towards the trigger member prior to contacting the
trigger member, the article carriers being able to tip fully once conveyed past the trigger
member. A partial tipping of an e carrier followed by a full tipping is a more gentle
movement than a direct full tipping.
Preferably, the actuation mechanism is operable to move at least part of the trigger member
laterally between the non-contact and contact positions. It will be understood that such a
“lateral” movement of the trigger member includes movements in which the trigger member
s around a pivot but the rotation is sufficiently small that the upper edge of the r
member moves generally horizontally. A lateral movement is beneficial from the perspective of
timing actuation of the trigger. Other lateral movements incorporating a sliding or more complex
mechanism may also be used.
In some embodiments of the invention, the trigger member comprises a recess in an upstream
portion thereof in relation to the conveying direction. More preferably, the recess is configured
such that trigger member avoids contacting the article carrier when the r member is in the
contact on and one of the article carriers has moved just past a downstream portion of the
trigger member. In one embodiment, the recess may be shaped to compliment the shape of a
part of the carrier frame. This e allows tolerance of a greater error in the timing of
actuation of the r member into the contact position.
Throughout this description, the terms “upstream” and “downstream” will be used to indicate
relative positions of components relative to the ion of travel of the conveyor, which is
d to be moving in the downstream direction.
In some exemplary embodiments, the trigger member is coupled to the actuation mechanism at
an upstream portion thereof. For example, the trigger member may be generally hook-shaped
with the point of the hook extending in the downstream direction.
In some embodiments of the invention, the tipping actuator is le to allow a first article
carrier on the s conveyor to be or have been tipped towards the trigger member and to
effect tipping of a second consecutive e carrier on the endless conveyor away from the
trigger member, the second utive article r being the article carrier on the endless
conveyor immediately following the first article carrier.
In said embodiments, the trigger member preferably comprises upstream and downstream
trigger member parts, each trigger member part being configured to effect g of the e
carriers if positioned in their path, wherein the upstream trigger member part is able to move
into the contact position upon actuation of the actuation mechanism if the downstream trigger
member part is constrained from moving into the contact position. For example, the downstream
trigger member may be constrained by the article carrier when tipped towards the trigger
member or otherwise constrained, for example, if the article carrier is in the carry position
wherein the upstream trigger can advantageously gain the position ed to make an
effective tip on the consecutive article carrier.
The tipping actuator may comprise a ramp located am of the trigger member and
ured to move an article carrier from an article discharge (tipped) position into an article
carriage (non-tipped) position.
According to a second embodiment of the invention, there is provided a tipping actuator for a
conveyor , the conveyor system comprising a plurality of article carriers moving on an
endless conveyor in a conveying direction, each article carrier having a carrier frame for bearing
an article, the carrier frame being pivotally mounted on the article carrier and operable to tip to
enable discharge of the article borne on the carrier frame, the tipping actuator comprising:
r means having at least one contact portion for contacting the article carriers; and
trigger ion means operable to move the trigger means into a contact position, in
which the t portion(s) is positioned in the path of the article carriers to make contact
therewith and effect tipping thereof,
wherein the contact portion(s) comprises at least one contact surface sloped towards the
conveying direction and having at least two nts.
Preferably, the r means comprises one sloped contact e, the sloped contact surface
having at least two gradients.
Preferably, the sloped contact surface ses at least a first section and a second section,
the first section being located upstream of the second section in relation to the conveying
direction, the first section having a steeper gradient than the second section.
In some embodiments of the invention, at least part of the sloped contact surface of the contact
portion is curved. For example, the first and/or second section may be curved.
In some embodiments of the invention, the first and/or second section may be substantially
straight. The sloped contact surface may comprise a curved transition section between the first
and second sections.
ably, the r means is configured such that, when a first contact surface contacts the
article carrier, a locking member of the article carrier is lifted from a locked position, in which the
carrier frame is unable to pivot on the article carrier, into an unlocked position, in which the
carrier frame is able to pivot on the e r. More preferably, the trigger means is
configured such that, when a second contact surface contacts the article carrier, the carrier
frame is tipped from the second article ge position into an article discharge on.
In some embodiments of the invention, the tipping actuator comprises upstream and
downstream trigger member parts, each r member part being configured to effect tipping
of the article carriers if positioned in their path, wherein the am trigger member part is
able to move into the contact position upon actuation of the actuation mechanism if the
downstream trigger member part is constrained from moving into the contact position. For
example, the downstream trigger member may be constrained by the article carrier when tipped
towards the trigger member.
More preferably, each trigger member part comprises at least one contact surface for contacting
the article carriers sloped towards the conveying direction and having at least two gradients.
The upstream and ream trigger member parts may be independently le.
According to a third embodiment of the invention, there is provided a tipping actuator for a
conveyor system, the or system comprising a plurality of article carriers moving on an
endless conveyor in a conveying direction, each article carrier having a carrier frame for bearing
an article, the carrier frame being pivotally mounted on the article carrier and operable to tip to
enable discharge of the article borne on the carrier frame, the tipping actuator comprising:
a trigger member having a contact portion for contacting the article carriers; and
an armature coupled to the r member, the armature comprising or having d
thereon an armature magnet; and
an electromagnet sing a core;
wherein the electromagnet is switchable n on and off states to cause the
armature magnet to be attracted to and repelled from the electromagnet, movement of the
armature causing the trigger member to move between a contact position, in which the contact
portion is oned in the path of the article carriers to make contact therewith and effect
tipping f, and a non-contact position, in which the contact portion is positioned out of the
path of the article carriers so as to avoid contact therewith.
Preferably, a portion of the trigger member comprises the armature.
More ably, the trigger member is pivotally mounted and configured to pivot on activation /
deactivation of the electromagnet.
In some exemplary embodiments of the invention, the trigger member is pivotally mounted to
pivot around a substantially horizontal axis.
In one embodiment, the trigger member comprises the armature at an end distal to the contact
portion, the trigger member being pivotally d at a point between the armature and
contact n.
Preferably, when the electromagnet is in an off or de-activated state, the armature magnet is
attracted to the core of the electromagnet. More preferably, when the armature magnet is
attracted to the core of the electromagnet, the r member is in the non-contact position.
The core of the electromagnet may be formed from a ferromagnetic material, such as iron or
other ferrous material.
ably, when the electromagnet is in an on or activated state, the armature magnet is
repelled from the core of the electromagnet. More preferably, when the armature magnet is
repelled from the core of the electromagnet, the trigger member is in the t on.
The tipping or may be configured such that the armature magnet is mounted on a surface
of the armature facing towards the conveyor and the electromagnet is positioned between the
or and the armature. This es for a t arrangement and reduces the extent to
which the tipping actuator extends outwards from the conveyor.
In some embodiments of the invention, the tipping actuator comprises upstream and
downstream trigger member parts, each trigger member part being configured to effect tipping
of the article carriers if positioned in their path, wherein the upstream trigger member part is
able to move into the contact position upon actuation of the ion mechanism if the
ream trigger member part is constrained from moving into the contact on. For
example, the downstream r member may be constrained by the article carrier when tipped
towards the trigger member.
In said embodiments, the first electromagnet may be configured to cause the upstream trigger
member part to move n the contact and ntact positions and the tipping actuator
may comprise a further electromagnet comprising a further core switchable between on and off
states to cause the downstream trigger member to move between the contact and non-contact
positions. The further electromagnet may be operated in conjunction with, or independently
from, the first electromagnet.
According to a fourth embodiment of the invention, there is provided a g actuator for a
or system, the conveyor system comprising a plurality of article carriers moving on an
endless conveyor in a conveying direction, each article carrier having a carrier frame for bearing
an article, the carrier frame being pivotally mounted on the article carrier and operable to tip to
enable discharge of the article borne on the carrier frame, the tipping or comprising:
a trigger member having a contact portion for contacting the article carriers; and
an actuation mechanism operable to move the trigger member between a non-contact
position, in which the contact portion is positioned out of the path of the article carriers so as to
avoid contact therewith, and a contact position, in which the contact portion is positioned in the
path of the article carriers to make contact therewith and effect tipping thereof away from the
trigger member,
wherein the tipping actuator is operable to allow a first article carrier on the s
conveyor to be or have been tipped towards the trigger member and to effect tipping of a
second article carrier on the endless conveyor away from the trigger member, the second article
carrier being the article carrier on the endless conveyor immediately following the first article
carrier.
Preferably, the trigger member comprises upstream and downstream trigger member parts,
each trigger member part being configured to effect tipping of the article carriers if positioned in
their path, n the upstream trigger member part is able to move into the contact position
upon actuation of the actuation mechanism if the downstream r member part is
ained from moving into the contact position. For example, the downstream trigger
member may be constrained by the article carrier when tipped towards the trigger member.
More preferably, each trigger member part comprises at least one contact surface for contacting
the article carriers sloped towards the conveying direction and having at least two gradients.
The upstream and downstream trigger member parts may be independently operable.
It will be apparent that the tipping actuators of any of the first, , third or fourth
embodiments of the invention may be provided in combination with the tipping ors of any
of the other ments of the invention.
According to a fifth embodiment of the invention, there is provided a conveyor system
comprising:
an endless conveyor configured to move in a conveying direction;
a plurality of article rs d on the endless conveyor, each article r having
a carrier frame for bearing an article, the carrier frame being pivotally mounted on the e
carrier and operable to tip to enable discharge of the article borne on the carrier frame; and
at least one g actuator according to any one or more of the first, second or third
embodiments of the invention mounted in operable relation to the article carriers.
ably, the conveyor system comprises at least two tipping actuators situated on opposing
sides of the endless conveyor. More preferably, the two tipping ors are positioned directly
opposite one another.
The conveyor system may further comprise at least one discharge station at one or more
locations along the endless conveyor for receiving articles from the article carriers. More
preferably, each discharge station is positioned on the te side of the endless conveyor to
the tipping actuator operable to cause articles to be discharged into the respective discharge
n. More preferably still, at least two discharge ns are positioned directly opposite one
another.
Further aspects of the invention, which should be considered in all its novel aspects, will
become apparent to those skilled in the art upon reading of the ing ption which
provides at least one example of a practical application of the invention.
Brief Description of the Drawings
One or more embodiments of the invention will be described below by way of example only, and
without intending to be limiting, with reference to the following drawings, in which:
Figure 1 is a side view illustration of a tipping actuator according to an embodiment of the
invention;
Figure 2 is a cross-sectional view ration of the tipping actuator shown in Figure 1;
Figure 3 is a cross-sectional view illustration of the tipping actuator shown in Figure 2 in
an alternative configuration;
Figure 4 is a rear view illustration of the tipping actuator shown in Figures 1 to 3 in use
with an endless conveyor according to one embodiment of the invention;
Figure 5 is a side view illustration of the conveyor system shown in Figure 4;
Figure 6 is another side view illustration of the conveyor system shown in Figure 4;
Figure 7 is another side view illustration of the conveyor system shown in previous s;
Figure 8 is another side view illustration of the conveyor system shown in the other
figures;
Figure 9 is a front view illustration of the tipping actuator shown in Figure 4 without an
article being supported by the e carrier;
Figure 10 is a side view illustration of a tipping actuator according to another embodiment
of the invention; and
Figure 11 is an isometric view ration of a or system according to one
embodiment of the invention.
ed Description of Preferred Embodiments of the Invention
Throughout the following description, unless specifically indicated otherwise, like reference
numerals refer to like components.
Tipping actuator
Figure 1 is a side view ration of a tipping actuator 10 according to an embodiment of the
ion. Figure 2 is a cross-sectional view illustration of the tipping actuator 10 shown in
Figure 1.
Tipping actuator 10 comprises a g 11a adapted to be mounted on the side of an endless
conveyor. In the embodiment shown, the tipping actuator 10 further comprises r housing
11b adapted to be mounted on the te side of the conveyor to housing 11a. Housings 11a
and 11b may be joined in some way, for example by a bracket 12. The two sides of tipping
actuator 10 may be formed and may function in exactly the same way so, for the purposes of
the ing description, only one side of the tipping actuator will be described although the
same description may also apply to the other side of the actuator. It is noted that not all
components of the left hand side of g actuator 10 are illustrated in Figure 2. In alternative
embodiments of the invention, the tipping actuator comprises only one of the sides of the tipping
actuator shown in Figure 2.
Between the two sides of tipping actuator 10 is formed a conveyor channel 17 h which an
endless conveyor is able to pass.
Tipping actuator 10 comprises a trigger member 13 pivotally mounted on the housing 11a and
ing upwards therefrom. The upper portion of the trigger member 13 comprises a contact
portion 14, which will be described in detail later. The end of the trigger member 13 distal from
the contact portion 14 comprises an armature 15, which comprises or has mounted thereon a
magnet 16. Trigger member 13 is able to pivot about a point between the armature 15 and
contact portion 14 by virtue of its mounting in housing 11a. The trigger member is thus able to
move n a contact position, in which the contact portion 14 is positioned inwardly as
shown on the right hand side of Figure 2, and a non-contact position, in which the contact
portion is positioned outwardly as shown on the left hand side of Figure 2.
Inside housing 11a there is an electromagnet having a magnetic (for example a ferromagnetic
or ferrous) core 18 with a solenoid 21 wound around it. The electromagnet is able to be
switched on and off by a control device to cause the fixed pole magnet 16 to be repelled from
and attracted to the electromagnet, which moves the trigger member 13.
Figure 3 is a sectional view ration of the tipping actuator 10 shown in Figure 2 but
with the trigger member in the non-contact position rather than the contact position (which is
shown in Figure 2).
The default position for the trigger member 13 is the non-contact position as shown in Figure 3,
in which the magnet 16 is attracted to the ic core 18 of the electromagnet. Since magnet
16 is a permanent magnet, no energy is required to maintain the trigger member in the noncontact
position.
To actuate the trigger member 13 into the t position shown in Figure 2, the electromagnet
is energised by a le control device. The solenoid winding 21 is configured to cause the
electromagnet to repel magnet 16, i.e. by causing the electromagnet to be formed with a pole at
the outwards facing end that is the same as the pole of the magnet 16 at the inwards facing
end. Repulsion n the electromagnet and magnet 16 causes the armature 15 to move
away from the electromagnet and the trigger member to move into the contact position shown in
Figure 2.
This trigger actuation mechanism is highly robust and will only fail if the fixed polarity magnet
loses its ism. The mechanism therefore has a longer lifespan compared to actuation
mechanisms using a spring or the like to bias the trigger to its default position. A spring is
vulnerable to fatigue and clogging with small components. In addition, the mechanism described
herein has only a single bearing surface that contacts the e carriers, which reduces
susceptibility to wear compared to mechanisms with more bearing surfaces.
While any type of magnet or electromagnet may be used, in one ary ment, the
magnet 16 is a fixed polarity magnet. A fixed polarity magnet may be used on account of its high
nce, or strength. It will be understood that the “magnetic core” of the electromagnet is a
core formed from any material that is attracted to a magnet.
In the embodiment shown in Figures 2 and 3, one e of a trigger member actuation
mechanism is illustrated but it will be evident that other ements are also possible without
departing from the scope of the invention. For example, while the trigger member 13 moves
laterally between the contact and non-contact positions in the embodiment shown, the trigger
member may alternatively be oriented differently and move in another direction between the
said positions. In another example, the pivot axis could be arranged vertically rather than
horizontally.
In the embodiment of Figures 2 and 3, the r member 13 comprises the armature 15 as an
al part thereof. It will be apparent that, in other embodiments, the armature may be
mechanically coupled to the r member in another appropriate manner.
Furthermore, in the embodiment of Figures 2 and 3, the electromagnet is oned between
the conveyor channel 17 and the armature 15 with the magnet 16 mounted on a surface of the
armature facing the conveyor channel 17. This arrangement provides a compact lateral extent
of the tipping or 10, meaning the width that the actuator protrudes out the side of the
conveyor is reduced. When conveyors are situated adjacent to one another, minimal lateral
extent means articles from adjacent conveyors have more room to be discharged. However it
will be apparent that, in other embodiments, other arrangements are possible. For example, the
trigger member may be pivotally ed at a bottom end, with the magnet oned above
the pivot.
In some embodiments, the solenoid of the electromagnet may be surrounded by a metal casing,
for example made from a sheet metal material. When made from a ferromagnetic material, the
metal casing may help to channel magnetic flux ed by the electromagnet to increase the
efficiency of the solenoid. Insulating material may be ed between the solenoid and the
metal casing to mitigate the possibility of sparking.
In some embodiments, the housing 11a in which the actuation mechanism is housed may also
be made from a similar sheet metal material to further increase the efficiency of the
electromagnet. In fact, it has been found that constructing the components of the actuation
mechanism such that a magnetic circuit is , e.g. by making many ents of the
actuation mechanism from a ferrous material, increases the strength of the electromagnet and
therefore the acceleration of the trigger. This reduces the time taken for the r to move into
the path of an article carrier, increasing the tolerance of the system to timing errors.
A ramp 19 may be comprised as part of the g actuator 10 or as a separate ent.
The arrow on the ramp 19 shown in Figure 1 tes the conveying direction of the conveyor
with which tipping actuator 10 is configured to be used. As such, the ramp 19 is located
upstream of the trigger member 13 in relation to the conveying direction. The ramp 19 slopes
upwards in the downstream direction and its function will be described below. In some
embodiments, the ramp may be integrally formed with the housing 11a.
Conveyor system
Figure 4 is a rear view illustration of the tipping actuator 10 shown in Figures 1 to 3 in use with
an endless conveyor 20 according to one embodiment of the invention. Figure 9 is a front view
illustration of the same tipping actuator and conveyor without an article being supported by the
article carrier. The tipping or 10 is mounted on the endless conveyor 20 by means of a
fixing 19, for example a screw, so that the conveyor passes h the conveyor channel 17
between the tipping actuator housings 11a and 11b. The endless conveyor 20 may be formed in
any suitable manner, but in the embodiment shown ses a series of chain links 21 joined
end-to-end and operable to move around a conveyor extrusion 22.
d on the endless conveyor 20 is a plurality of article carriers 23, of which one is shown in
Figure 4. The article carriers 23 are mounted on the conveyor in any appropriate manner, for
example by means of a mounting clip 24. Each article r comprises a carrier frame 25,
which in turn includes a support surface 26 and rollers 27 which together define a cup for
bearing an article 28.
The carrier frame 25 is mounted on the mounting clip 24 by means of a pivotal connection 29.
This allows the carrier frame 25 to move between a carriage position, in which the support
surface 26 is generally horizontal and article 28 is supported by the article carrier, and a
discharge position, in which carrier frame 25 has tipped from the carriage position so that the
support surface 26 is not horizontal and the article 28 discharges from the article r under
gravity. The r frame is shown in the carriage position in Figure 4. Pivotal connection 29
may comprise a stop to limit the extent to which the carrier frame 25 can pivot.
As described in the applicant’s US patent no. 7,410,044, the article carrier 23 or carrier frame 25
may comprise a latch or locking member 30 that is moveable between two different positions. In
one on of the locking , the carrier frame 25 is unable to pivot on the mounting clip
24 by virtue of an appropriate pivot g mechanism. This is referred to as the locked
carriage configuration. In the second position of the locking member, the r frame is free to
pivot as has been described and the g mechanism is ed. This is referred to as the
unlocked carriage configuration. In exemplary embodiments, the carrier frame is in the locked
carriage configuration when the locking member is in a low position on the ng clip and
can be raised into the ed position by, for example, a portion of trigger member 13.
When the locking member is in the unlocked on, the carrier frame is able to be tipped by
means of a trigger actuator such as those according to embodiments of the invention described
herein. Some part of the locking member 30 or, in other embodiments some part of the carrier
frame, presents a surface able to be contacted by the trigger actuator to effect the tipping. In the
embodiment shown in Figure 4, locking member 30 comprises lever arms 30a and 30b that
extend sideways outwards from the article carrier and comprise a contact surface on their
undersides able to be ted by the contact portions 14 of trigger members 13. The locking
member 30 is contacted and pushed s against the carrier frame 25 to cause the carrier
frame to tip.
Operation of the g actuator
Operation of the tipping or 10 will be now be described in relation to Figure 4 and Figures
and 6, which are side view illustrations of the conveyor system shown in Figure 4. Figure 5
illustrates the system from one side and Figure 6 is an ration from the other side. In both
s 5 and 6, the passage of a single article carrier 23 is represented by a time progression
of positions as it s on the conveyor.
By default, the trigger members are in the non-contact position, for example as is shown by
trigger member 13a in s 4 and 6. That is, the trigger member 13a is positioned out of the
path of the article carriers, and in particular out of the path of the lever arm of the locking
member 30, so contact is avoided as the article carrier 23 moves past the trigger member 13a.
For example, the arrangement of the trigger actuation mechanism shown in Figure 2 results in
the trigger member 13a being situated lly outside the path of the article carriers.
Each trigger member is able to be selectively actuated into the contact position in which it lies in
the path of the next article carrier 23 passing by on the conveyor by control of the associated
electromagnet. Trigger member 13b of Figures 4 and 5 is shown in the contact position. As can
be seen most clearly in Figure 5, the trigger member 13b is dimensioned such that, when it is in
the contact position, the article carrier is impinged by the trigger member and the contact
surface on the underside of the lever arm 30b is contacted by the upper surface of the contact
portion of trigger member 13a. This causes the g member 30 to be pushed upwards on
the side nearest trigger member 13b to unlock the carrier frame 25 and further to cause the
carrier frame to tip away from the trigger member 13b and to discharge the article 28 on the
opposite side of the conveyor to the trigger member 13b.
In contrast to the applicant’s existing system described in the Background to the Invention
section of this document, which has a trigger member that flicks upwards to impact t the
article carriers to effect their g, the present invention requires less energy to e the
trigger member to cause tipping of the article carriers because the trigger member needs to
move through a smaller distance to be activated. This also makes the t invention
significantly less noisy when in operation than the existing system. In addition, the energy that
causes the carrier to tip in the invention is generated by the conveyor itself – it is the motion of
the conveyor against the trigger member that causes the tipping action. The discharge of
different weight articles can therefore be controlled by controlling the speed of the conveyor
without altering the actuation of the trigger. For example, to prevent light articles flying off the
conveyor, the conveyor can be slowed slightly. The ility of heavy articles being failed to
be rged by a trigger mechanism lacking sufficient energy is also avoided since the energy
g the discharge comes from the motion of the conveyor.
The locking member 30 comprises lever arms on both sides so that trigger members can be
positioned on both sides of the conveyor and the article carriers can be tipped in either direction
to discharge articles on either side of the conveyor. This may be useful when sorting or grading
produce as more outlets can be situated in the same conveyor space compared to if the
or could only discharge articles on one side. It may be particularly useful to situate trigger
s directly opposite each other on the conveyor. In this configuration, the carrier frame
moves towards trigger member 13a when it is tipped away from trigger member 13b. This
presents a risk that the trigger member on the side the carrier frame is tipped towards could
prevent the carrier frame tipping properly.
To address this, the tipping members, when in the non-contact position, are ured and
positioned to avoid contact with the carrier frames when a carrier frame is tipped towards it. In
one example, the tipping members are sufficiently far away from the conveyor in the noncontact
position that the carrier frames do not t them. However, this results in a wide
conveyor system, which impacts on the number of conveyors able to be situated in a given
area, and a trigger member that has to move a large ce between the contact and tact
positions, which may require more energy and greater movement time compared to a
more compact conveyor. Therefore, in some embodiments of the invention, such as shown in
Figure 6, the trigger member 13a is configured to be received by a portion of the carrier frame
when the carrier frame 25 is tipped towards the trigger member. That is, trigger member 13a fits
under a laterally extending arm 32 of the support surface 26 in the gap formed between the
l ion 32 and the r frame. As a result, trigger member 13a does not prevent the
carrier frame from tipping. In this embodiment, the conveyor system is t in its width and,
as shown in Figure 4, the trigger actuator may not extend outwards beyond the width of the
carrier frame 25.
It can be seen in Figure 6 that, shortly after the trigger member 13b has contacted the lever arm
30b (as shown by the article carrier in position X), the article carrier has partly tipped towards
r member 13a and, as described above, the uration and position of trigger member
13a allows such partial tipping. In some embodiments, the trigger member 13a in the noncontact
on may be configured to prevent full tipping of the article carrier until the article
carrier has moved forwards on the conveyor to position Y. This may be desirable since an l
partial tipping of the article carrier followed by a full tipping may make the tipping movement
gentler than if the article carrier was d to ately tip fully. This may ensure articles
are discharged from the conveyor without excessive violence, increasing the chances of the
article being discharged to the intended destination, for example an outlet chute.
The embodiments of trigger actuators according to the invention shown in the Figures are
tailored for use with one of the ant’s existing conveyor systems. There are significant
ages for those already using the applicant’s conveyor systems to benefiting from the
advantages of the invention t the need to replace the conveyor systems. However the
invention is not limited to use only with the applicant’s own systems, which are illustrated herein
by way of example only. It will be apparent that trigger actuators within the scope of the
invention may be ed to operate with any appropriate conveyor .
Profile of the r
Referring again to Figure 1, the contact portion 14 of the trigger member 13 will now be
discussed in more detail. The upper surface of the contact portion 14 is the part of the trigger
member 13 that contacts the article carriers to effect their g. The contact e generally
slopes upwards in the conveying direction so that the surface slopes towards the ing
direction. This slope allows the lever arm of the article carrier to be contacted and pushed
upwards by the trigger member.
The shape of the t surface is configured to ease contact between the trigger member 13
and the article carriers. Embodiments of the invention comprise a contact surface having at
least two nts, for example the contact surface may comprise two or more traight
sections, as shown in the embodiment of Figure 1, or the contact surface may be curved.
In the embodiment of Figure 1, the contact surface comprises three surface sections 101, 102
and 103. First surface section 101 is on the upstream end of the contact surface of the trigger
member 13 and is the lowest of the three sections. It also has the steepest gradient. This
section is designed to make first contact with the locking member lever arm of an article carrier
that impinges on the trigger member. In embodiments in which the article carrier comprises a
carrier frame that can transition between locked and unlocked carriage configurations by means
of moving the locking member vertically between locked and unlocked positions, the first
surface section 101 is of ient height to lift the locking member from the locked to the
unlocked position.
Second surface section 102 transitions the gradient of the contact surface between the first
surface section 101 and the third surface section 103, which is the highest of the three sections
and has the west gradient. The third e section is at a sufficient height to lift the
locking member lever arm of the article carrier so that the article carrier tips over, as has been
bed above.
This stepped or gradual reduction in gradient of the contact surface of the trigger assists in
controlling tipping of the article r. Rather than an impact that could cause articles on the
carrier to get thrown off, the contact surface first unlocks the article carrier and then causes a
gradual tipping.
It will be evident that the invention includes embodiments in which separate triggers are
ed, one which causes the unlocking of the article carrier and another that causes the
tipping. However the use of a single trigger to perform both actions may be more efficient and
less x to construct.
Trigger member recess
As shown in Figure 1, a recess 110 may be provided in an am portion of the trigger
member 13. The trigger member 13 is generally hook-shaped, with the point of the hook
pointing am and the recess 110 formed by the hook.
One purpose of the recess 110 will now be described with reference to Figure 7, which is
another side view illustration of the conveyor system shown in previous figures. Unlike Figures 5
and 6, Figure 7 illustrates three article carriers 23a, 23b and 23c mounted one after another on
the conveyor system. Trigger member 13 is shown in the non-contact position and allows the
article carriers to pass by unimpinged.
r member 13 is at the same height as the locking member lever arms 30 of the article
carriers 23 so that, when in the t position the trigger member contacts the lever arm of the
next article carrier and causes it to tip. This limits the window of opportunity available to actuate
the trigger prior to the arrival of the article r that needs to be tipped. The trigger can only
be actuated once the lever arm of the previous article carrier, which may not need to be tipped,
has passed by.
In the embodiment shown in the Figures, the lever arm 30 comprises a thin flange extending
laterally out of the side of the carrier frame. As shown in Figure 7, when an article carrier is in
the position of article carrier 23c, it has sufficiently passed by the trigger member 13 for the
trigger member to close without contacting the lever arm 30. This is possible because the shape
of the recess 110 of the r member 13 compliments the shape of lever arm 30. ore
the r member can be actuated as soon as the article carrier has got to the position of
carrier 23c. This increases the tolerance in the timing of actuation compared to a similar system
in which the recess 110 is not present and the trigger member extends downwards from the
hooked end. Such a tolerance in timing of actuation reduces the accuracy and complexity
required in the control system and also allows the operation of the conveyor system to tolerate
variations in timing over the course of time, for example the tendency for conveyors to stretch
slightly with prolonged use.
Ramp
As mentioned above with reference to Figure 1, the tipping or 10 may comprise a ramp 19
located upstream from the trigger member 13. The e of ramp 19 will now be described
with reference to Figure 8, which is a side view illustration of the conveyor system shown in the
other figures with a single article carrier 23 shown in a number of different positions
ponding to its nt to the left in Figure 8 over time.
In Figure 8, article carrier 23 is initially in the discharge or tipped position (shown on the right
hand side of Figure 8). The article carrier 23 may have tipped accidently or have been tipped by
an upstream tipping actuator. Ramp 19 rights the tipped article carrier. That is, it causes the
e carrier 23 to move from the article discharge or tipped position into the article carriage or
non-tipped position. Ramp 19 is configured to engage the lever arm of the locking member 30
and slope upwards in the downstream direction to sufficient height for the carrier frame 25 to be
stably brought into the carriage position. The shallow gradient of ramp 19 ensures the carrier
frame is not righted with too much momentum which could cause the carrier frame to tip in the
opposite direction.
It will be iated that ramps may be positioned at any point along the conveyor system
where the e carriers need to be righted and not only immediately upstream of a tipping
actuator.
Using ramps to right the e carriers helps to reduce wear and increase the an of a
or system. If many article carriers are left tipped for a long stretch of a conveyor, their
weight may affect the balance of the conveyor and cause wear on one side.
Double trigger actuator
In a or system, tipping one article r in one direction and the immediately following
article r in the opposite direction may be problematic. The tipping actuator for the latter
article carrier may only be activated once the first article carrier (that is tipped towards the
tipping actuator) has passed. This is because the tipping actuator may be impeded by a part of
the article carrier. This therefore gives a short period of time in which to activate the trigger and
for the trigger to move into position to contact the following article carrier. The available period
of time in which to te the trigger may be particularly short where the speed of the conveyer
is high or the spacing n article carriers is small.
In one embodiment of the invention, the positioning of the pivot of the actuator trigger is
sufficiently high that the degree of movement of the trigger member is small and it can be
moved into position quickly. However this may result in a high degree of tolerance being needed
during manufacture and a smaller tolerance to wear, meaning that tipping malfunctions are likely
to happen sooner prior to parts needing to be replaced.
Figure 10 is a side view illustration of a tipping actuator 80 according to another embodiment of
the invention. Tipping actuator 80 is similar in many respects to tipping actuator 10 shown in
Figure 1 and like references are used in relation to like parts. In the following, only those parts of
tipping actuator 80 differing from tipping actuator 10 will be described.
The trigger member 83 of tipping or 80 comprises an upstream trigger member part 83
and a downstream trigger member part 82. Each of the am and ream trigger
member parts 81 and 82 is configured to cause tipping of the article rs if positioned in their
path, as described above.
In operation, upstream r member part 81 is able to move into position to contact an article
carrier even if downstream trigger member part 82 is constrained from . Such a situation
is illustrated in Figure 11, which is an isometric view illustration of a conveyor system 90
according to one embodiment of the invention. In Figure 11, the article carriers 91 are moving
diagonally away and to the right. Article carrier 91a has been tipped towards tipping actuator 80
by another tipping or on the other side of the conveyor (not shown in Figure 11) so that
article 92a is g off the conveyor towards the tipping actuator 80. However, article 92b on
carrier 91b needs to be tipped in the other direction, i.e. away from tipping actuator 80, and
therefore tipping or 80 is actuated.
To ensure the trigger member of tipping actuator 80 is moved into the path of carrier 91b in time
to tip it over, tipping actuator 80 has been actuated while a part of carrier 91a is still level with
the tipping actuator 80. The presence of carrier 91a when it is tipped towards tipping actuator 80
prevents all of the trigger member from moving into the path of the article carriers 91. However,
at the point shown in Figure 11, upstream trigger member part 81 is free to move into the path
of the e carriers while downstream r member part 82 is still constrained from moving
by the presence of article carrier 91a. As a result, upstream trigger member 81 is able to move
early to ensure that article carrier 91b is tipped in the opposite direction to article carrier 91a.
In another embodiment of the invention, full ion of the tipping actuator may be impeded by
the roller part of the e carrier. In such an embodiment, the upstream trigger member may
only be free to move into the path of the article rs after the roller has moved sufficiently far
downstream.
In a preferred ment of the invention, the upstream and downstream trigger member parts
81 and 82 are ted by separate electromagnets but the two electromagnets are activated
together. In this embodiment, both trigger member parts are triggered together but they each
only move into the contact position when they are not constrained from doing so. Therefore, in
the situation described in relation to Figure 11, the upstream trigger part 81 will move first,
followed by the downstream trigger part 82.
In an alternative embodiment of the invention, the upstream and downstream trigger member
parts may be able to be activated by separate actuation mechanisms. This may allow only the
upstream trigger member to be triggered in a situation (such as the situation shown in Figure
11) when constrained movement is likely, which may help to avoid damage to the trigger
member, depending on the actuation ism used. In a still further embodiment, the
upstream and ream trigger members may selectively be operable together or
independently.
The profile shape of trigger member 83 in the ment of Figure 10 is similar to that of the
trigger member 13 shown in Figure 1 but the upstream and downstream trigger member parts
81 and 82 can be ged as being formed by splitting trigger member 13 vertically in two.
The shape of the interface of gap between the upstream and downstream trigger member parts
in Figure 10 is such that the ream trigger member 82 comprises an upper contact
surface that is sloped towards the conveying direction and has at least two gradients, as has
been described in more detail above. As a result, if the upstream trigger part 81 fails to activate
(for whatever reason), the downstream trigger part 82 is shaped to tip the article carriers in a
r manner as bed above in relation to the single trigger member embodiments of the
invention. In the embodiment shown in Figure 10, the interface or gap between the top of the
upstream and downstream trigger parts 81 and 82 is at the point at which the upper contact
surface of the trigger member 83 changes.
Control system to sort / grade
It will be understood that the conveyor system described herein may be used to sort or grade
articles of any type although particular ation may be found in the field of fruit sorting and
grading.
A sorting or grading apparatus may comprise an endless conveyor of the type bed above
and a g or sorting means such as a weighbridge, optical scanner or the like. A l
system tracks the movement of the article carriers around the conveyor and activates trigger
actuators to sort articles by certain characteristics, as measured by the grading or sorting
means, by discharging articles of the same teristics into the same discharge station,
which may comprise a r conveyor, chute or other e receiving means.
As has been described, the present invention advantageously allows tipping actuators to be
oned on ly ng sides of the endless conveyor to make efficient use space while
still benefiting from other advantages of the invention described above or evident to the skilled
addressee.
Unless the context clearly requires otherwise, throughout the description and the claims, the
words ise”, “comprising”, and the like, are to be construed in an inclusive sense as
opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not
limited to”.
The entire disclosures of all applications, s and publications cited above and below, if any,
are herein incorporated by reference.
Reference to any prior art in this specification is not, and should not be taken as, an
acknowledgement or any form of suggestion that that prior art forms part of the common general
knowledge in the field of endeavour in any country in the world.
The invention may also be said broadly to consist in the parts, elements and features referred to
or indicated in the specification of the application, individually or collectively, in any or all
combinations of two or more of said parts, elements or features.
Where in the foregoing description reference has been made to integers or components having
known equivalents thereof, those integers are herein incorporated as if individually set forth.
It should be noted that various changes and modifications to the presently preferred
embodiments described herein will be apparent to those skilled in the art. Such s and
cations may be made without departing from the spirit and scope of the invention and
without diminishing its ant advantages. It is therefore intended that such changes and
modifications be included within the present invention.