Note: Descriptions are shown in the official language in which they were submitted.
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A Coupler
FIELD OF THE INVENTION
This invention relates to a coupler, and in particular, but not exclusively to
a coupler for
attaching work implements to the arm or boom of an excavator or similar
vehicle.
BACKGROUND
Couplers are often used to connect work attachments or implements to the booms
of
excavators, diggers, back hoes, etc. The couplers are sometimes also referred
to as "quick
hitches", or "pin grabber" couplers as they grab the two connecting pins that
are attached
to many attachments for the purpose of connecting the attachment to an arm.
The couplers allow implements to be changed quickly and efficiently by being
able to
release the connecting pins of one implement, and to grab the connecting pins
of another,
using remotely controlled hydraulic actuators on the coupler.
The ability to quickly change implements however, has lead to an increasing
number of
accidents involving implements coming loose, or falling from diggers etc. Most
couplers
today will have a safety locking feature that will hold one of the pins of an
implement if
the coupler fails, or if the other pin comes free for some reason.
Experience shows that a single safety lock feature is not sufficient.
Accidents are still
occurring as a result of the use of these quick change couplers having a
single safety
feature. While it is possible to add additional safety locks, the locks need
to be robust to
withstand the harsh environment and rough treatment that couplers experience
at the end
of an excavator arm. For example, dirt or other foreign matter can accumulate
within
coupler components which may affect the operation of the coupler or its safety
features.
For this reason any additional safety locks need to be relatively simple and
durable, to
ensure high levels of reliability of the locks.
There are also limitations concerning the number of hydraulic lines that are
used to
control hydraulic couplers. Simply adding additional lines for each additional
safety lock
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is not always convenient and can be costly to install and maintain. There is a
requirement
to provide additional safety features without the need for additional
hydraulic lines.
In this specification unless the contrary is expressly stated, where a
document, act or item
of knowledge is referred to or discussed, this reference or discussion is not
an admission
that the document, act or item of knowledge or any combination thereof was at
the
priority date, publicly available, known to the public, part of common general
knowledge;
= or known to be relevant to an attempt to solve any problem with which
this specification
is concerned.
OBJECT
It is therefore an object of the present invention to provide a coupler which
will at least go
some way towards overcoming one or more of the above mentioned problems, or at
least
provide the public with a useful choice.
STATEMENTS OF THE INVENTION
Accordingly, in a first aspect, the invention may broadly be said to consist
in a coupler
assembly for coupling implements having a first connecting pin and a second
connecting
pin, to a vehicle, the coupler having;
a body component that is connectable to the vehicle, and which includes a
forward
recess for receiving the first connecting pin,
a movable component which is supported by the body component and which is
movable through a range of travel relative to the body component, and which
includes, or forms a part of, an aft recess for receiving the second
connecting pin,
and,
a movable component actuator for selectively moving the movable component -
relative to the body component,
a rear locking member which is a part of the movable component and which is
movable relative to the movable component between an extended position in
which the rear locking member prevents the second connecting pin from exiting
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the aft recess and a retracted position in which the rear locking member does
not
prevent the second connecting pin exiting the aft recess,
and a rear lock actuator for moving the rear locking member between its
extended
and retracted positions.
Preferably a connection between the rear lock actuator and the rear locking
member
includes a link member.
Preferably the rear locking member and the link member are configured in such
a manner
that;
an initial range of movement of the link member pushes the rear locking member
from its retracted position to its extended position, and
a second and further range of movement of the link member positions a stop
member which prevents movement of the rear locking member away from its
extended position.
Preferably the stop member is a part of the link member.
Preferably the rear lock actuator is mounted on the movable component.
Preferably the movable component slides relative to the body component.
Preferably the link member slides relative to the movable component.
Preferably the rear locking member is pivotally connected to the movable
component.
Preferably the coupler further includes a forward locking member which is
movable
relative to the body component between an extended position in which the
forward
locking member prevents the first connecting pin from exiting the forward
recess and a
retracted position in which the forward locking member does not prevent the
first
connecting pin exiting the forward recess.
Preferably the coupler includes a forward lock actuator for moving the forward
locking
member between its extended and retracted positions.
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Preferably the forward lock actuator is pivotally connected to a hydraulic
manifold of the
coupler assembly.
Preferably the pivotal connection between the forward lock actuator and the
hydraulic
manifold is configured to provide a hydraulic fluid flow path between the
hydraulic
manifold and the forward lock actuator.
Preferably the movable component actuator, the rear lock actuator and the
forward lock
actuator are all hydraulic actuators.
Preferably a hydraulic system of the coupler includes sequence valves to
control the
sequence of operation of the movable component actuator, the rear lock
actuator and the
forward lock actuator during any engagement and/or disengagement processes.
In a second aspect, the invention may broadly be said to consist in a coupler
assembly for
coupling implements having a first connecting pin and a second connecting pin,
to a
vehicle, the coupler assembly having;
a forward recess for receiving the first connecting pin,
an aft recess for receiving the second connecting pin,
a forward locking member for securing the first co/meeting pin within the
forward
recess,
a hydraulic system including at least one actuator configured to enable the
coupler
assembly to positively engage with the first and second connecting pins of an
implement, and
the hydraulic system also including at least one hydraulic manifold block;
wherein the coupler assembly also includes a hydraulic forward lock actuator
which is
supported on, and receives a hydraulic supply from, the hydraulic manifold
block.
Preferably forward lock actuator is pivotally connected to the hydraulic
manifold block.
Preferably the hydraulic supply from the hydraulic manifold block to the
forward lock
actuator passes through the pivotal connection between the forward lock
actuator and the
hydraulic manifold block.
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Preferably the forward lock actuator is a single acting actuator with a spring
return
mechanism.
In a third aspect, the invention may broadly be said to consist in a vehicle
incoiporating at
least one coupler substantially as specified herein.
Preferably the vehicle is an excavator.
In a fourth aspect, the invention may broadly be said to consist in a method
of
disengaging a work attachment or implement from a coupler having a body and a
movable
component, including the steps of;
operating a forward lock actuator to move a forward locking member from an
extended position to a retracted position,
operating a rear lock actuator to move a rear locking member from an extended
position to a retracted position,
and when the rear locking member is in its retracted position, operating a
movable
component actuator to move a movable component out of engagement with a rear
pin of the work attachment,
and then disengaging a forward pin of the work attachment from the body.
Preferably the method of disengaging includes an automatic operation of the
forward lock
actuator to move the forward locking member from the retracted position to the
extended
position a pre-determined time period after the operation of the forward lock
actuator, the
rear lock actuator or the movable component actuator to disengage the coupler
from an
implement.
The invention may also broadly be said to consist in the parts, elements and
features
referred to or indicated in the specification of the application, individually
or collectively,
and any or all combinations of any two or more of the parts, elements or
features, and
where specific integers are mentioned herein which have known equivalents,
such
equivalents are incorporated herein as if they were individually set forth.
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DESCRIPTION
Further aspects of the present invention will become apparent from the
following
description which is given by way of example only and with reference to the
accompanying drawings in which:
FIGURE 1 is an exploded perspective view of a first example of a coupler
according to the present invention,
FIGURE 2 is a cutaway perspective view of the first example of a coupler,
FIGURE 3 is a cutaway perspective view of a slide assembly of the first
example
of a coupler,
FIGURE 4 is a perspective view of a slide component of the slide assembly,
FIGURE 5 is a perspective view of a forward locking member of the first
example of a coupler,
FIGURE 6 is a perspective view of a rear locking member of the slide assembly,
FIGURE 7 is a perspective view of a link member of the slide assembly,
FIGURE 8 is a perspective view of a slide assembly actuator of the first
example
of a coupler,
FIGURE 9 is a right side elevation view of the first example of a coupler,
FIGURE 10 is a cutaway side elevation view of the first example of a coupler,
FIGURE 11 is a perspective view of a rear lock actuator of the first example
of a
coupler,
FIGURE 12 is a cutaway side elevation view of the coupler showing a first
stage
of a coupling sequence,
FIGURE 13 is a cutaway side elevation view of the coupler showing a second
stage of a coupling sequence,
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FIGURE 14 is a cutaway side elevation view of the coupler showing a third
stage
of a coupling sequence,
FIGURE 15 is a cutaway side elevation view of the coupler showing a fourth
stage of a coupling sequence,
FIGURE 16 is a cutaway side elevation view of the coupler showing a first
stage
of an uncoupling sequence,
FIGURE 17 is a cutaway side elevation view of the coupler showing a second
stage of an uncoupling sequence,
FIGURE 18 is a cutaway side elevation view of the coupler showing a third
stage
of an uncoupling sequence,
FIGURE 19 is a cutaway side elevation view of the coupler showing a fourth
stage of an uncoupling sequence,
FIGURE 20 is a cutaway side elevation view of the coupler showing a fifth
stage
of an uncoupling sequence,
FIGURE 21 is a schematic diagram of a hydraulic circuit which includes
components of the coupler as well as hydraulic components of a
vehicle, to which the coupler is attached,
FIGURE 22 is an electrical diagram used to control the operation of the
coupler,
FIGURE 23 is a partially cutaway side elevation view of a second example of a
coupler according to the present invention, showing a forward
locking member of the coupler in an extended configuration,
FIGURE 24 is a partially cutaway side elevation view of the second example of
a
coupler showing the forward locking member in a retracted
configuration,
FIGURE 25 is a partially cutaway perspective view of the second example of a
coupler which defines an exploded view A, and
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FIGURE 26 is the exploded view A which shows the hydraulic supply routing to
a forward lock actuator which controls the positioning of the forward
locking member.
FIRST EXAMPLE
With reference to Figures 1 to 22, a first example of a coupler assembly (31)
is shown in
an exploded perspective view and in a series of perspective and cutaway views.
Included
also are hydraulic and electrical circuits used to control the operation of
the coupler
assembly (31). The coupler assembly (31) is of the type typically used for
coupling
implements having a first connecting pin and a second connecting pin, to a
vehicle such as
an excavator or a back hoe.
It can be seen in Figures 1 and 2 that the coupler assembly (31) has a body
component
(33) that is connectable to the vehicle. The body component (33) itself
includes two
coupler mounting pins (35) which are used to connect the coupler assembly (31)
to the
end of an arm of the vehicle. The body component (33) also includes a forward
recess
(37) for receiving the first connecting pin of an implement.
The coupler assembly (31) also includes a movable component or slide assembly
(39)
which is supported by the body component (33). The slide assembly (39) is
movable
through a range of travel relative to the body component (33). The range of
travel of the
slide assembly (39) is substantially in a fore and aft direction relative to
the body (33).
The slide assembly (39) includes, or at least forms a part of, an aft recess
(41) for
receiving the second connecting pin of an implement.
A movable component actuator or slide assembly actuator (43) of the coupler
assembly
(31) is used to selectively move the slide assembly (39) relative to the body
component
(33). With reference to Figure 4 it can be seen that-a slide component-(45)-
of-the slide
assembly (39) includes elongate tabs (47). These elongate tabs (47) engage
with
corresponding slots (49) on the body component (33), allowing the slide
assembly (39) to
slide in a fore and aft direction relative to the body component (33).
The slide assembly (39) includes a rear locking member (51). The rear locking
member
(51) is movable relative to the slide assembly (39), between an extended
position in which
the rear locking member (51) prevents the second connecting pin from exiting
the aft
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recess (41) and a retracted position in which the rear locking member (51)
does not
prevent the second connecting pin exiting the aft recess (41).
The slide assembly (39) also includes a rear lock actuator (53) (refer Figures
2, 3 and 11)
for moving the rear locking member (51) between its extended and retracted
positions.
The rear lock actuator (53) is mounted on the slide assembly (39), and moves
with the
slide assembly (39). The rear lock actuator (53) includes a rear lock actuator
spring (54)
which biases the actuator toward an extended configuration in which the rear
lock
actuator (53) pushes the rear locking member (51) to its extended position.
A feature of the coupler assembly (31) is the connection between the rear lock
actuator
(53) and the rear locking member (51). The connection includes a link member
(55). The
rear locking member (51) is pivotally connected to the slide component (45) by
a rear
lock connecting pin (57). The link member (55) slides fore and aft relative to
the slide
assembly (39) under the influence of the rear lock actuator (53).
The rear locking member (51) and the link member (55) are configured in such a
manner
that an initial range of movement of the link member (55) pushes the rear
locking member
(51) from its retracted position to its extended position. And a second and
further range
of movement of the link member (55) positions a stop member (59) which
prevents
movement of the rear locking member (51) away from its extended position. In
this
example, the stop member (59) is a part of the link member (55).
It can be seen in Figure 7 that the link member (55) is in the form of a
substantially
rectangular shaped plate (61), having tabs (63) extending from the plate (61)
for
connection to the rear lock actuator (53). The plate (61) includes a
rectangular shaped
hole (65) positioned substantially centrally within the principal plane of the
plate (61).
Alternatively, it could be said that the link member (55) comprises . forward
transverse
member (67), and aft transverse member (69), and side plates (71), one on the
left side
and one on the right side of the link member (55). The side plates (71) each
span between
the outermost extremities of the forward and aft transverse members (67) and
(69).
The side plates (71) of the link member (55) engage with, and slide within,
slide grooves
(73) on each side of the slide assembly (39).
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Similarly, it can be seen in Figure 6 that the rear locking member (51)
includes an
upwardly protruding control tab (75), and two rearwardly extending locking
tabs (77).
The two rearwardly extending locking tabs (77) each include a locking surface
(79). The
locking surfaces (79) are situated on an upper part of each locking tab (77)
and are
substantially aligned with a lower edge (81) of the slide grooves (73) when
the rear
locking member (51) is in its fully extended position.
When the slide assembly (39) is assembled, the link member (55) is held within
the slide
grooves (73). And when the rear locking member (51) is in its fully extended
position,
the control tab (75) of the rear locking member (51) is situated within the
rectangular hole
(65) in the link member (55). The rectangular hole (65) is of sufficient size
to allow a
range of movement of the link member (55) relative to the rear locking member
(51)
without contact being made between the link member (55) and the rear locking
member
(51). However, movement of the link member beyond this range of movement does
result
in contact between the link member (55) and the rear locking member (51). And
this
contact is used to move the rear locking member (51) between its retracted
position and
its extended position as will be explained below.
Movement of the rear locking member (51) from its retracted position to its
extended
position is achieved as follows. The link member (55) is moved from its
forward most
position, and in an aft direction, by the rear lock actuator (53). During an
initial range of
movement of the link member (55) in an aft direction, an aft edge (83) of the
side plates
(71) contacts a forward edge (85) of the locking tabs (77). This contact
causes rotation of
the rear locking member (51) about the rear lock connecting pin (57), and
rotation of the
rear locking member (51) to its fully extended position.
__________________________________________________________________________
Continue-d movement of-the link member (55) in an aft direction does not cause
any
further movement of the rear locking member (51), however the continued
movement
positions the side plates (71) of the link member (55) over the locking
surfaces (79) of the
rear locking member (51). The rectangular hole (65) in the link member (55) is
configured to allow continued aft movement of the link member (55) even though
the
control tab (75) is now situated within the rectangular hole (65). Also, the
slide assembly
(39) is configured such that the locking surfaces (79) are immediately
adjacent the side
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plates (71) when the link member (55) is fully aft. In this way, the side
plates (71) act as
stops preventing movement of the rear locking member (51) away from its fully
extended
position.
Any forces experienced by the rear locking member (51), for example if the
second
connecting pin of a work implement was trying to exit the aft recess (41),
would result in
the locking surfaces (79) bearing upwards against the under side of the side
plates (71).
This upward force from the locking surfaces (79) would be restrained by the
engagement
of the link member (55) within the slide grooves (73). This is advantageous in
that these
forces experienced by the rear locking member (51) are not felt directly by
the rear lock
actuator (53).
Movement of the rear locking member (51) from its extended position to its
retracted
position is achieved as follows. The link member (55) is moved forward by the
rear lock
actuator (53). An initial range of forward movement of the link member (55)
moves the
side plates (71) away from their location above the locking surfaces (79).
This unlocks
the rear locking member (51) allowing it to be moved to its retracted
position. A second
range of forward movement of the link member (55) initially brings a forward
edge (87)
of the rear transverse member (69) into contact with a rear surface (89) of
the control tab
(75).
Continued forward movement of the link member (55) pushes the control tab (75)
forward
causing the rear locking member (51) to move to its retracted position. The
rear locking
member (51) is held in its retracted position by the rear transverse member
(69) which lies
above the control tab (75) and adjacent to it, when the rear locking member
(51) is in its
retracted position.
The coupler assembly (31) further includes a forward locking member (91). The
forward
locking member (91) is movable relative to the body component (33) between an
extended position, in which .the forward locking member (91) prevents the
first
connecting pin from exiting the forward recess (37), and a retracted position,
in which the
forward locking member does not prevent the first connecting pin exiting the
forward
recess (37).
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The coupler assembly (31) also includes a forward lock actuator (93) for
moving the
forward locking member (91) between its extended and retracted positions.
In this example, the coupler assembly (31) is used with a hydraulic control
system (111)
and an electrical control circuit (113) as shown in Figures 21 and 22
respectively.
The electrical control circuit (113) includes two manually controlled switches
and a timer,
and the hydraulic control system (111) includes solenoid operated control
valves and
sequence valves, to control the sequence of operation of the slide assembly
actuator (43),
the rear lock actuator (53) and the forward lock actuator (93),. during any
engagement
and/or disengagement processes. The design of the hydraulic control system
(111) allows
the coupler assembly (31) to be controlled using only two hydraulic lines. The
electrical
and hydraulic control systems will now be explained in further detail.
The electrical control circuit (113) has a master switch (115) which is used
to supply or
disconnect electrical power to the control circuit. When the master switch
(115) is
switched on an alarm (117) sounds and optionally a warning light operates
also. This
warns personal in the vicinity of the vehicle that the coupler (31) will be
operated to
release and/or engage implements from the aim of the vehicle.
A second switch (119) is a 'hold to run' style of switch, meaning that the
contacts of the
switch are only engaged while the operator continues to hold the switch down.
When the
second switch (119) is pushed "on" a second alarm (121) and warning light
operates, and
power is supplied to a first solenoid operated valve (123) of the hydraulic
control system
(111). A timer (125) is also initiated, which in turn provides power to a
second solenoid
operated valve (127) via a timer relay (128), after a pre-determined time
period, for
example a time period in the range of three to eight seconds.
The first and second solenoid operated valves (123) and (127) of the hydraulic
control
system (111) are situated on the vehicle along with a pressure regulating
valve (129) for
regulating the hydraulic pressure to a set value and minimising pressure
spikes. The first
solenoid operated valve (123) is used to initiate the disengage or engage
signals to the
coupler (31). The second solenoid operated valve (127) controls the draining
of hydraulic
fluid from the forward. lock actuator (93) after the pre-determined time delay
period to
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allow a forward lock actuator spring (99) within the forward lock actuator
(93) to move
the forward locking member (91) backs to its extended position.
Two hydraulic lines, a supply line (131) and a return line (133), are used to
power and
control the coupler assembly (31).
The coupler assembly (31) itself includes a first sequence valve (135) which
controls the
sequencing of the three actuators and ensures that the rear lock actuator (53)
and the
forward lock actuator (93) operate to retract their respective locking members
(51) and
(91) prior to the retraction of the slide assembly actuator (43) to move the
slide assembly
(39) forward.
A first pressure operated check valve (137) and a second pressure operated
check valve
(139) act as safety locks to lock the position of the slide assembly actuator
(43) in case of
a hydraulic failure. The locked slide assembly actuator (43) holds the slide
assembly (39)
fixed preventing the pins of an implement from exiting the forward and aft
recess (37) and
(41) of the coupler (31).
A second sequence valve (141) controls the sequencing of the slide assembly
actuator
(43) and the rear lock actuator (53) to ensure that the rear lock actuator
(43) moves the
rear locking member (51) to its retracted position before the slide assembly
actuator (43)
begins to move the slide assembly (39) aft.
A third pressure operated check valve (143) isolates the rear lock actuator
(53) from the
forward lock actuator (93) when fluid is drained from the forward lock
actuator (93) by
the second solenoid operated valve (127) as described above.
With reference to Figures 15 to 20 the dis-engagement-sequence will now be
described.
At the beginning of this sequence (refer figure 15) the slide assembly
actuator (43) is at
least partly extended and is holding the slide assembly (39) in engagement
with an aft
connecting pin (95) of an implement. The rear lock actuator (53) is extended
under
hydraulic pressure and the rear locking member (51) is in its extended
position and is able
to prevent the aft connecting pin (95) from exiting the aft recess (41). The
forward lock
actuator is retracted under spring tension only and is holding the forward
locking member
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(91) in its extended position and is able to prevent a forward connecting pin
(97) from
exiting the forward recess (37).
To initiate the disengagement procedure, the master switch (115) is switched
on. Then
the second switch (119), the 'hold to run switch' is depressed. The first
solenoid operated
valve (123) then operates to provide hydraulic pressure to the return line
(133). Due to
the configuration of the first sequence valve (135) the hydraulic pressure is
initially
directed to the rear lock actuator (53) and the forward lock actuator (93) to
retract the rear
and forward locking members (51) and (91) ¨ refer to figure 16.
When the rear lock actuator (53) and the forward lock actuator (93) have
operated,
pressure in the return line (133) builds until the first sequence valve (135)
opens to allow
pressure to the retract side of the slide assembly actuator (43) and to the
pilot line of the
first pressure operated check valve (137), allowing the slide assembly
actuator (43) to
retract and to move the slide assembly (39) fully forward ¨ refer to figure
17. This
disengages the aft connecting pin (95) from the aft recess (41).
Then the coupler assembly (31) is rotated, for example by using the crowd
actuator of the
excavator, to allow the coupler assembly (31) to be moved aft without re-
engaging with
the aft connecting pin (95) in the aft recess (41) ¨ refer figure 18.
Then the coupler assembly (31) is moved aft to disengages the forward
connecting pin
(97) from the forward recess (37) to complete the disengaging procedure ¨
refer figure 19.
Figure 20 shows the subsequent movement of the forward locking member (91) to
its
extended position after the time delay period. After the set time period, the
second
solenoid operated valve (127) operates to vent the fluid from the forward lock
actuator
(93), allowing a spring--(9) within the forward lock actuator (93) to retract
the actuator
and move the forward locking member (91) to its extended position. The
pressure
operated check valves (137), (139) and (143) prevent any movement of fluid
from the
slide assembly actuator (43) and the rear lock actuator (53). This automatic
resetting of
the forward locking member (91) to its extended position is a safety feature
ensuring that
the forward locking member (91) is ready to hold and secure the forward
connecting pin
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(97) of the next implement in the forward recess (37) as soon as the pick up
or
engagement procedure begins.
With reference to Figures 12 to 15 the engagement sequence will now be
described.
The rear locking member (51) is retracted, and as noted above, the forward
locking
member (91) is extended and ready to hold and secure the forward connecting
pin (97).
The coupler assembly (31) is manipulated, for example using the arm of the
excavator, to
engage the forward connecting pin (97) of the next implement within the
forward recess
(37). The forward locking member (91) is configured so that it is pushed away
from its
extended position by the forward connecting pin (97) as it enters the forward
recess (37) ¨
refer to figure 12. The coupler assembly (31) is configured such that the
spring (99)
pushes the forward locking member (91) back to its extended position once the
forward
connecting pin (97) has passed fully into the forward recess (37) ¨ refer to
figure 13.
The operator of the excavator then rotates the coupler assembly (31) until the
body (33)
touches the aft connecting pin (95) of the implement. And then the 'hold to
run' or
second switch (119) is released by the operator. This causes the first
solenoid operated
valve (123) to become de-energised and it returns to its steady state
configuration as
shown in figure 21. This connects the hydraulic supply pressure to the supply
line (131).
This supplies hydraulic pressure to the extend side of the slide assembly
actuator (43) and
opens the second pressure operated check valve (139) allowing the slide
assembly
actuator (43) to extend and to move the slide assembly (39) aft toward the aft
connecting
pin (95) ¨ refer to figure 14.
When the slide assembly (39) engages with the aft connecting pin (95) the
pressure builds
on the extend side of the slide assembly actuator (43) until there is
sufficient pressure to
operate the second sequence valve (141). Then pressure is supplied to the
extend side of
the rear lock actuator (53), the rear lock actuator (53) then extends and
moves the rear
locking member to its extended position ¨ refer to figure 15.
This is the configuration that the coupler assembly (31) remains in while the
excavator or
other vehicle is using the coupler assembly (31) to hold an implement. A first
locking
feature is provided by the first and second pressure operated check valves
(137) and (139)
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which hydraulically lock the slide assembly actuator (43) in the case of a
hydraulic
failure, for example a rupture of the supply or return lines (131) or (133). A
second
locking feature is provided by the forward locking member (91) which holds the
forward
connecting pin (97) within the forward recess (37). And a third locking
feature is
provided by the rear locking member (51) which holds the aft connecting pin
(95) within
the aft recess (41).
It can be said that in use, the coupler assembly (31) employs the following
method of
disengaging a work attachment or implement from the coupler assembly (31);
the forward lock actuator (93) is operated to move the forward locking member
(91) from its extended position to its retracted position,
the rear lock actuator (53) is operated to move the rear locking member (51)
from
its extended position to its retracted position,
and when the rear locking member (51) is in its retracted position, the slide
assembly actuator (43) is operated to move the slide assembly (39) out of
engagement with a rear pin (95) of the work attachment,
and when the forward locking member (91) is retracted and the rear pin (95) is
no
longer engaged within the slide assembly (39), the forward pin (97) of the
work
attachment is disengaged from the body (33).
With the coupler assembly (31), the method of disengaging also includes an
automatic
operation of the forward lock actuator (93) to move the forward locking member
(91)
from the retracted position to the extended position a pre-determined time
period after the
operation of;
the forward lock actuator (93),
the rear lock actuator (53), or
the slide assembly actuator (43),
to disengage the coupler (31) from an implement.
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SECOND EXAMPLE
With reference to Figures 23 to 26, a second example of a coupler assembly
(161) will
now be described. The operation of the coupler assembly (161) is similar to
that of the
first example of a coupler assembly (31), and the only significant difference
between the
first and second examples is the configuration of a forward locking assembly
(163).
In this second example, a forward lock actuator (165) of the forward locking
assembly
(163) is pivotally connected at its aft end to a hydraulic manifold block
(167) of the
coupler assembly (164 In this way the forward lock actuator (165) is supported
by the
hydraulic manifold block (167). The hydraulic manifold block (167) routes
fluid for a
slide actuator (169) and a rear lock actuator (171), and also routes hydraulic
fluid directly
to the forward lock actuator (165).
A pivot pin (173) connects an aft end of the forward lock actuator (165) to
the hydraulic
manifold block (167). A first passage (175) within the hydraulic manifold
block (167)
communicates with a second passage (177) within the pivot pin (173). The
second
passage (177) communicates with the hydraulic cylinder (179) of the forward
lock
actuator (165) via a third passageway (181) in an end fitting (183) of the
forward lock
actuator (165).
In this way, hydraulic fluid can be directed to or from the forward lock
actuator (165) to
extend or retract a forward locking member (185). As can be seen in Figure 26,
the
forward lock actuator (165) is a single acting actuator with a spring return
mechanism.
For this reason the forward lock actuator (165) only requires a single
hydraulic supply.
This configuration eliminates the need for an external hydraulic connection to
the forward
lock actuator (165), while at the same time allowing the forward lock actuator
(165) to
pivot as it moves the forward locking member (185). This allows a compact
configuration of the forward locking assembly (163), and the configuration is
expected to
have a high reliability.
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VARIATIONS
To those skilled in the art to which the invention relates, many changes in
construction
and widely differing embodiments and applications of the invention will
suggest
themselves without departing from the scope of the invention as defined in the
appended
claims. The disclosures and the description herein are purely illustrative and
are not
intended to be in any sense limiting.
In the examples described above, the slide assembly actuator, the rear lock
actuator and
the forward lock actuator are all hydraulic actuators. However it is envisaged
that
alternative actuators could be used, for example electrically operated linear
actuators.
DEFINITIONS
Throughout this specification the word "comprise" and variations of that word,
such as
"comprises" and "comprising", are not intended to exclude other additives,
components,
integers or steps.
ADVANTAGES
Thus it can be seen that at least the preferred form of the invention provides
a coupler
which provides a high level of safety. The rear locking member locks the aft
connecting
pin positively within the aft recess and the arrangement of the rear lock
actuator and its
connection to the rear locking member provides a positive and robust lock of
the rear
locking member in its extended position. The configuration of the locks is
relatively
simple and not excessively prone to interference from dirt or other foreign
matter that may
accumulate around the components.
The coupler assembly can be controlled using only two hydraulic lines which is
advantageous as it eliminates the need for additional lines where two are
already
available.
Also, the hydraulic actuators for the slide assembly, for the forward lock and
the rear lock
are all isolated from one another, meaning that in the event of a failure of
one of the
actuators, the other two will continue to provide their safety locking
features. In addition,
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each actuator includes a biasing means in the form of a spring which biases
each actuator
toward a fail-safe configuration, that is, a configuration which retains the
pins of the
implements within the coupler.
