GB2463298A

GB2463298A - A coupler for an excavator

Info

Publication number: GB2463298A
Application number: GB0816495A
Authority: GB
Inventors: Gary Miller
Original assignee: Miller UK Ltd
Current assignee: Miller UK Ltd
Priority date: 2008-09-09
Filing date: 2008-09-09
Publication date: 2010-03-10
Anticipated expiration: 2028-09-09
Also published as: GB2463298B; GB0816495D0

Abstract

A quick coupler 10 for attaching a tool to an excavator arm comprising a frame 18, a first latch 38 to close a first jaw 24 and a second latch 26 driven relative to the frame 18 to close a second jaw 22, in which as the second latch 26 moves to open the second jaw 22, it contactingly moves the first latch 34 to close or further close the first jaw 24, the two latches not being joined or linked. Methods for attaching or removing the tool from the coupler with the coupler in the normal rather than inverted position, in which the second latch 26 is moved to a fully extended position when there is no pin in a second jaw 22 to allow the pin in the first jaw 24 to be removed. The first latch 34 may be gravity operated, it may not block movement of the second latch 26, and it may comprise two components, one 36 to close the first jaw 24 and one 38 to interact with the second latch 26.

Description

A COUPLER FOR AN EXCAVATOR

The present invention relates to couplers for attaching an accessory, such as an excavator bucket, to an excavator arm of an excavator.

Many couplers have been developed in the art. Some are part automatic and part manual, requiring many or most operations for coupling and decoupling of an accessory to or from the coupler to be carried out from within the cab (and thereby being part automatic), but with one or more operations needing to be done instead at the coupler itself (thereby being part manual), whereas others are fully automatic, i.e. fully operable from within the cab of the excavator for both coupling and decoupling of an accessory to or from the coupler.

A part automatic and part manual coupler is disclosed in GB2359062. The coupler is attached remotely, i.e. "automatically" to the accessory, i.e. from within the cab of the excavator, via a multi-step connection process. The first step is to hook a front jaw of the coupler onto a front attachment pin of the coupler (the first part of the connection). The second step is then to drop a rear jaw of the coupler onto a rear attachment pin of the accessory. The third step is then to secure that second pin within that rear jaw by using a pivoting latching hook (the second part of the connection). Then the final, manual, securement step is taken. This final step is to secure that connection using a safety pin -the safety pin is manually inserted into a position in front of the pivoting latching hook for blocking/preventing the release of that latching hook from its latching position.

A fully automatic coupler, on the other hand, is disclosed in GB2330570. That coupler similarly has a multi-step connection process, with a similar first and second part connection between the accessory and the coupler. However, in place of the manually insertable safety pin, this fully automatic coupler uses a gravity operated blocking bar for providing the final securement step -the gravity operated blocking bar is arranged to fall in front of the rear latching hook whenever the coupler is in a normal, in-use, generally upright, and locked orientation in such a way that it cannot be lifted again purely by the forces that are able to be applied by the pivoting latching hook -the blocking bar therefore falls "over-centre" relative to the blocking bar's pivot point and the latching hook's point of engagement with the blocking bar. That blocking bar therefore provides the same blocking function as the safety pin of the coupler disclosed in GB2359062. As a result, during normal use of an accessory attached to the coupler, the latching hook of the coupler is prevented from being released from a latching position by the presence of the blocking bar in front of it.

The fully automatic coupler also allows a fully automatic release of an attachment: the blocking bar can be remotely lifted from its blocking position, i.e. from within the cab, by a separate hydraulic piston in one embodiment, or more usually by using gravity: by inverting the coupler from within the cab, e.g. by manipulation of the excavator arm, the blocking bar can fall out of its blocking position.

There are also many other couplers that are either fully automatic or part automatic and part manual. See, for example, Australian Patent AU557890, German Utility Model DE2O1 19092U, European Patent Application EP1318242, GB Patent GB2332417, US Patents US5692325, US6132131 and US7306395, and PCT Publications W099/42670 and W008/0291 12.

The present invention, however, seeks to provide a new coupler of the fully automatic type. Further, the coupler is to be specifically for coupling attachments to an excavator arm of an excavator, rather than to a front end loader of an excavator, or a bulldozer.

This latter distinction is important since the two different locations require different coupler designs, and those designs are generally are not freely interchangeable. This can be due to 1. their different relative sizes, 2. the different relative spacings of the various attachment points thereof, and 3. the different loading characteristics applied thereto -the different loading characteristics lead to different locations for the high stress points within their respective frames, and thus different structural design requirements for the frames of the couplers.

Some fully automatic couplers, such as those of W008/0291 12 and GB2330570, have a distinct advantage over other fully automatic couplers -they comprise very few complex components (i.e. multi-part components). Instead they predominantly consist of simple mechanical members or components, such as levers or fixed members, which may only require the occasional application of grease to keep any movable joints serviceable.

Indeed, in some couplers the only complex component is the hydraulic cylinder that is provided for driving the latching hook forwards or backwards. Such couplers include the above mentioned coupler with the gravity operated blocking bar. However, a difficulty can occur with gravity operated couplers, since it is not always possible to invert a coupler during its use. That is because, to invert a coupler, it is generally necessary for a part of the excavator arm to be extended above the roof of the cab, e.g. when the arm is folded, and the coupler is rotated, into the crowd position. Therefore such inversions might not be possible when ceiling height constraints occur around the excavator, e.g. in tunnels, or inside buildings. As a result, it would be desirable to provide a fully automatic coupler that addresses this problem, but without adding to the coupler any additional complex moving parts or components, such as additional second hydraulic rams or the like..

The present invention therefore provides a coupler for attaching an accessory to an excavator arm of an excavator, the coupler comprising: a frame, a first moveable component that provides a latch that is associated with, and that is adapted to close, at least partially and selectively, a first jaw, the first jaw forming a first half of a first part of an accessory connection between an accessory and the coupler, a second movable component that forms a part of first half of a second part of the accessory connection, and a drive means for moving the second movable component relative to the frame between a latching position and a non-latching position, wherein the first movable component is interactable with the second movable component, such that movement of the second movable component from a latching position into a non-latching position causes movement of the latch, that movement of the latch either causing the closing of the jaw or causing a further closing of the first jaw; characterised in that: the first movable component can selectively bear against the second movable component at a point of contact for allowing that interactive movement to occur, but wherein the first movable component is not linked or joined to the second movable component at that point of contact.

For the first jaw to be referred to as "closed", the extent of closure of the first jaw by the latch needs to be such that an attachment pin of a preselected size (i.e. diameter) cannot pass into or out of the first jaw without first moving the latch.

Preferably the first movable component is gravity operated, whereby it is gravity that causes the first movable component to bear against the second movable component.

Preferably the geometry of the first movable component relative to the second movable component is such that the first movable component cannot jam against the second movable component in such a manner that the first movable component would block the movement of the second movable component. To assist with that, the first movable component preferably has a bevelled, rounded or smoothly profiled surface for engaging against the second movable member. The geometry of the respective components is also preferably such that there can be no over-centering orientation of the components, relative to any of their axes of rotation and themselves, during the ranges of motion experienced by them during use of the coupler. For that purpose, one or more rotation stop can be provided to limit the respective ranges of rotation or movement of either or both of the first and second movable components.

The first jaw may be formed in the frame of the coupler, or in a separate component welded to, or otherwise joined to, the frame of the coupler.

The first jaw is preferably formed from hardened steel.

The second movable component may be a pivoting latching hook. In an alternative embodiment the second movable component may be a sliding latch or plate.

The second movable component is preferably biasable or movable into a latching position by either a spring or a hydraulic ram. However, other drive mechanisms that are known in the art, for example a screwthread drive, could alternatively be provided for that purpose.

The second movable component may be associated with a second jaw.

Where the second movable component of the coupler is a hook, the coupler is for attaching to an accessory that has a pair of suitably spaced attachment pins, i.e. pins spaced to fit within the two jaws, when two jaws are provided. However, accessories can also be provided on which only a single attachment pin is provided. In such accessories, in place of the second attachment pin, one or more hooks, spaced from the single attachment pin, are usually provided. For coupling onto that style of accessory, the coupler's second movable component can be an attachment bar, or the like, for engaging the hook or hooks of the accessory.

In preferred embodiments, the second movable component is a pivoting latching hook; most accessory manufacturers adopt the dual, parallel, attachment pin, configuration.

Preferably the latching hook has a first (usually rearwardly facing) surface for engaging one of the attachment pins of the accessory.

The shape of the coupler's hook, and the shape of the hook's first surface, is preferably similar to that which was defined in GB2330569, the whole contents of which are incorporated herein by way of reference. Such an attachment hook has an upturned lip at its free end. The upturned lip resists the unintentional release of an attachment pin by the hook during, for example, a failure of the hook's biasing mechanism (e.g. the hydraulic ram). The hook, therefore, provides a security measure.

The first jaw of the coupler is spaced away from (usually forward of) the second movable component. Ii a preferred embodiment the first jaw points forwards relative to the frame, i.e. in a direction that is close to, or that is substantially along, the frame's longitudinal axis, and that is away from the second movable component.

Where a second jaw is provided, i.e. a jaw that is associated with the second movable component, the second jaw preferably points downwardly relative to the frame (i.e. its mouth is lowermost). Downwards refers to a direction that points generally transverse to the longitudinal axis of the frame, and generally away from the points at which the coupler is attached to the excavator arm of the excavator).

Where provided, the second jaw preferably has a mouth that is at least 50% wider than the mouth of the first jaw. The wider second jaw, when downwardly facing, allows a wide range of accessories to be connected to the coupler since the second jaw allows a wide range of pin spacings on the accessory to be accommodated -different accessories, e.g. from different manufacturers, or for different excavators, do not necessarily have the same pin spacing between their respective attachment pins.

The latch provided by the first movable component preferably comprises a first latch component and a second latch component. The first latch component is for selectively providing the at least partial closure of the first jaw -it can selectively extend at least part way across the mouth of the first jaw for preventing insertion or removal of an attachment pin into or from the jaw. (The extent of that closure is dependant upon the position, or orientation, of the first movable component relative to the frame.) With regard to the second latch component, it extends towards the second movable component, preferably from a pivot point located between the first and second latch components. The second latch component therefore is preferably the component of the first movable component that can selectively engage against the second movable component. That engagement is preferably a direct engagement, although the interaction with the second movable component might alternatively be through an intermediate member that likewise is not joined to or linked to the second movable component.

The two latch components of the first movable component may be unitarily formed, or they may be separately formed components that are connected together. Preferably they are pivotably connected together.

Preferably the first latch component extends generally downwards relative to the frame.

Preferably the second latch component extends generally rearwards relative to the frame.

Rearwards refers to a direction that is roughly opposite to the above-described forwards direction.

The latch formed by the first movable component may be mounted about a further pivot for pivotal rotation relative to the frame of the coupler. Preferably that further pivot is fixed relative to the frame, such as by a direct mounting of a pivot pin into the sides of the frame. The position of that further pivot is axially spaced from any pivot between the first and second latch components to allow rotation of the second latch component about that further pivot to cause movement of the first latch component about that further pivot.

Preferably the surface or surfaces of the first movable component that engage the second movable component, and the surface or surfaces of the second movable component that engage the first movable component, engage each other throughout the respective, in contact, ranges of motion of the two respective components such that any reaction force therebetween is directed so as not to cause an over-centering of the first movable component relative to its pivot point, whereby the first movable component will always respond to applied force from the second movable component by tending to rotate about its further pivot, rather than jamming against the second movable component.

Preferably the first jaw has a mouth and a widened interior (widened compared to the mouth of that first jaw). This provides a further security measure since it creates a resistance to accidental decoupling in the event of a failure of the second movable component. This feature is described in GB2433246, the whole contents of which are incorporated herein by way of reference.

Preferably the back of the front jaw defines a radiused throat. The radius of that throat is preferably selected to allow an attachment pin of an accessory to be accurately seated in the jaw to avoid "accessory rattle" during the use of the accessory (manufacturers tend to stick with a fixed attachment pin diameter for any given range of products intended for a particular excavator, whereby a suitable radius can readily be chosen for a given range of accessories).

To allow more than one range of products to be accommodated, the radiused throat of the first jaw may have two or more different, but distinct, radiused portions, whereby the coupler can accurately seat a wider selection of attachment pins, and thereby additional product ranges. This feature is also disclosed in GB2433246.

In a preferred embodiment, the two movable components are arranged such that they can directly contact each other for their interaction. However, as previously stated they are not linked together at that point of interaction. Further, it is preferred that that point of interaction is not a fixed point of interaction, or that it does not have a fixed pivot axis relative to the frame, and/or relative to the first movable component, and/or relative to the second movable component. Instead, during the range of motion that provides that interaction, it is preferred that the interacting surfaces of the two components slide relative to one another, perhaps with a relative pivoting action, but with the pivoting action having an axis that preferably moves together with the point of interaction. As such the connection is preferably a live connection that can exhibit degrees of sliding and relative pivoting, either both at the same time or separately, throughout the range of interactive motion of the two movable components.

The coupler of the present invention preferably has a top or first half for connecting to the excavator arm. That first half preferably has two spaced pairs of holes, formed in sideplates of the coupler. They are for receiving attachment pins of the excavator arm -i.e. the pins that would have otherwise attached an accessory to the excavator arm.

The coupler also preferably has a second or bottom half. The second half houses the or each jaw, and is the half to which an accessory, in use, is attached.

Preferably all moving parts of the coupler are positioned within the confines of the frame of the coupler, which confines include the areas contained within the jaws of the coupler.

As a result, external mechanical influences cannot easily cause an adverse operation of the coupler, other than by poking into the coupler.

In place of single first and second movable components, pairs of first and/or second movable components may be provided. Those pairs may be linked together such that they operate in unison, or they may operate independently.

Preferably the second movable component has a latching face that faces a first, or rearwards, direction. Where the second movable component is for engaging against an attachment pin of an accessory, that latching face is for bearing against that attachment pin. The second movable component then also has a second face that facing away from that latching face. Preferably the second face includes a curve against which an end of the first movable component may bear for sliding therealong during the respective movements of the first and second movable components.

The end of the first movable component that rests on that curved face is preferably itself smooth or rounded to facilitate the free sliding of that end along the curved surface. This further prevents jamming of the coupler's working mechanism.

There can be more than one point of contact between the first and second movable components. For example, during a preliminary range of interactive movements (i.e. from a latching position towards a non-latching position), there could be a first sliding point of contact. Then, during a later range of interactive movements towards that non-latching position, an alternative sliding point of contact may exist. A transition point will then occur during the range of interactive motion towards the non-latching position in which both sliding points of contact exist. A single, continuous, sliding point of contact, however, is preferred since it should reduce the possibility of impact-wear, as might occur at the transition point.

Preferably the second movable component is a pivotal member, mounted to the frame about a pivot pin. Preferably the member is a hook having a hook-like free end that extends generally rearwards relative to the frame for engaging the attachment pin in use.

The hook, however, preferably also includes, on its forwardly facing face (relative to the frame), a curved flange member that extends or curves generally forwards with respect to the frame. Preferably it curves forwards with respect to the frame from a straight arm section of the hook. Given this two-sided arrangement, the hook resembles a T-shaped, or anchor shaped, member.

That curved flange member preferably has an upturned nose to further enhance the resemblance of an anchor. In that regard it preferably has upturned, curved, free ends extending from both sides of its central shaft. The upturned nose on the forward facing side helps to ensure that the reaction force applied to the first movable component causes a positive lifting of the first movable component, rather than a jamming of the first movable component against the second movable component, even at the extremities of their respective ranges of interactive travel. For example, that upturned nose might be engaging an end of, or an area underneath, the first movable component at those extremes of travel.

Preferably the nose on the curved flange has a radiused tip, with a radius of at least 5mm, whereby it will smoothly slide against the first movable component.

Preferably the first movable component is a pivotal member, mounted to the frame about a second pivot pin -the further pivot, which pin is spaced from the second movable component. Preferably it is an arm that extends from that second pivot pin towards the second movable component for engaging thereagainst. Preferably the arm's free end has an underside with a contoured surface, i.e. a surface without sharp edges in a transverse plane, whereby the second movable component can smoothly slide in the longitudinal direction over the forward facing surface of the second movable component as the two components pivot about their respective pivot pins.

Preferably the contoured underside includes a depression for accommodating the nose of the second movable component during at least part of their respective ranges of interactive travel. Preferably that depression is concavely radiused, and preferably that radius has a minimum radius of at least twice the radius of the radiused tip of the nose.

The depression allows the first movable component, and specifically the arm thereof, to have a shorter range of rotation in response to the movements of the second movable component by having the radiused tip of the second movable component pass in or out of that depression at an end of its range of sliding interaction with the first movable component. That preferred features prevents the latch from traversing too far across the mouth of the jaw during its range of motion -to extend a long way across the mouth could make a lever arm that allows a failure to occur in the first jaw, unless the jaw and latch were suitable reinforced since a pin trying to exit past it from within the first jaw would generate larger lever forces on that lever arm if that lever arm is long, as compared to a shorter lever arm.

An additional benefit is that the reduced latch travel in response to movement of the second movable component increases the "gearing" between the latch and the second movable member, whereby the pin in the first jaw cannot force the latch upwards and out of its closed position, and whereby a reduced hydraulic force in the hydraulic ram is required to resist such movements, and similarly, to close the jaw.

The second movable component is adapted to be moveable into a non-latching position, from a latching position, by powering it generally in the direction that its second face faces. In the non-latching position, the second part of the accessory connection can be disengaged from the path of the second movable component, or it can be disengaged from the jaw associated therewith (i.e. the attachment pin in the second jaw can be rotated out of the second jaw). However, when the second movable component is in that non-latching position, due to the interaction of the first and second movable components, the latch of the first movable component will be in a position that at least partially closes the mouth of the first jaw. Thus, even though one attachment pin is released, the other attachment pin, i.e. the first part of the accessory connection, cannot yet be disengaged from the first jaw. An accidental, or premature, release is thus prevented.

For disengaging that first part of the accessory connection, the coupler of the present invention must be further operated. This further operation is a further novel feature of the present invention: while the second part of the accessory connection is disengaged, the second movable component is powered back to, and beyond, its earlier latching position, i.e. in the opposite direction to its previous movement. Shortly beyond that earlier latching position, the second movable component reaches a super-extended position. That super-extended position is a position in which the interaction between the two movable components will have allowed the first movable component to have moved into a latch release position. That latch release position is a position in which the first movable component has moved sufficiently to cause the latch to open the first jaw to a sufficient extent to allow the first attachment pin to exit through the mouth of the first jaw. Therefore, only then can the first part of the accessory connection be disengaged for fully releasing the accessory from the coupler.

In preferred embodiments, upon full release of an accessory, the coupler is then left in that fully released condition so that the first jaw remains open for allowing an attachment pin of another accessory to be inserted into that first jaw.

In another embodiment of the present invention, however, a hinged gate, or the like, might also be provided for the latch for allowing an attachment pin to be freely inserted into that first jaw irrespective of the orientation of the first movable component. See, for example, GB0808 113.5 for an example of such a hinged gate or the like, the entire contents of which are incorporated herein by way of reference. As shown therein, the hinged gate is designed only to open inwards, whereby an inserted attachment pin cannot then be removed from the jaw through the gate other than by opening the jaw in the above described manner, i.e. it is still necessary first to retract the latch by using the second movable component's super-extended position.

The present invention, therefore, also provides a new method of attaching, or detaching, an accessory to a coupler on an excavator arm of an excavator. The method of attaching comprises: a) providing an excavator with a powered excavator arm, the arm having a coupler on an end thereof, the coupler comprising two latches and at least a first jaw, the first jaw being associated with a first of the latches, and the second latch being a powered latch, powered for movement between a non-latching position, a latching position and a super-extended position, the first latch being moveable into a latching position by the powered latch as the powered latch is retracted from a super-extended position, and the first latch being moveable from a latching position into a non-latching position to open the jaw by extending the powered latch beyond a normal latching position into the super-extended position while the coupler is in a normal, in use, substantially level, orientation; b) providing an accessory with two attachment pins thereon sized and spaced to fit onto the coupler by engagement of one pin with the first jaw of the coupler and the other pin with the powered latch of the coupler;

L

c) manipulating the coupler with the excavator arm to locate a first attachment pin of the accessory into the first jaw; d) curling the coupler relative to the partially engaged accessory with the excavator arm, for locating the second attachment pin into a position for engagement by the powered latch, and powering the powered latch towards a normal latching position to latch the second attachment pin with the powered latch.

The attachment is now attached securely to the coupler.

In accordance with a preferred embodiment, the method further comprises the step of powering the powered latch to extend it into the super-extended position to open the first jaw prior to locating the first attachment pin within that jaw, and the step of powering the powered latch to retract it from its super-extended position to at least partially close the first jaw with the first latch prior to locating the second attachment pin into a position for engagement by the powered latch.

The method of detaching comprises: a) providing an excavator with a powered excavator arm having a coupler on an end thereof, the coupler comprising two latches and at least a first jaw, the first jaw being associated with the first of the latches, and the second latch being a powered latch, powered for movement between a non-latching position, a latching position and a super- extended position, the first latch being moveable from a latching position into a non-latching position by the powered latch while the coupler is in a normal, in use, substantially level, orientation; b) providing an accessory that is connected to the coupler, the accessory having two attachment pins thereon that are sized and spaced such that a first pin is engaged with the first jaw of the coupler and the second pin is engaged by the powered latch of the coupler, the powered latch being in the latching position; c) powering the powered latch to retract the powered latch into a non-latching position to release the second pin from the powered latch; d) curling the coupler relative the accessory with the excavator arm to swing the second pin away from the path of powered latch; e) powering the powered latch beyond its previous latching position into the super-extended position, that extended movement of the powered latch into the super-extended position, while the coupler is in a normal, in use, orientation, causing the first latch to be moved from its latching position into a non-latching position in which the first jaw is open; and f) manipulating the coupler relative to the accessory using the excavator arm to remove the first attachment pin from the first jaw of the coupler.

The accessory is now removed from the coupler.

The coupler used for the above methods is preferably a coupler in accordance with the previous aspects of the invention.

These and other preferred features and embodiments of the present invention will now be described purely by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic illustration of a first embodiment of the present invention with a second movable component located in a super-extended position; Figure 2 is a schematic illustration of the embodiment of Figure 1 with an attachment pin located in a first or front jaw of the coupler; Figure 3 is a schematic illustration of the embodiment of Figure 1 with the second movable component in a retracted position for opening a second or rear jaw of the coupler; Figure 4 is a schematic illustration of the embodiment of Figure 1 with both pins of the accessory secured into their respective jaws of the coupler both jaws are closed; Figures 5 to 7 illustrate the coupler of Figure 1 conducting a decoupling procedure; and Figure 8 illustrates an alternative embodiment of the present invention with differently shaped first and second movable components.

Referring first of all to Figure 1, a coupler of the present invention comprises a working mechanism within it. The working mechanism, and the coupler, are shown schematically as a cut-away, side elevation. The coupler 10 has a first, or upper, portion 12 and a second, or lower, portion 14. The coupler also has a front 16 and a rear 18. In normal use the front 16 points towards the cab of an excavator (not shown), whereas the rear 18 points away from the cab. It is possible, however, also to reverse-mount the coupler onto an excavator arm of the excavator. Nevertheless, for simplicity, the terms front and rear will be used in the following description in reference to the front and rear of the coupler when it is in its normal, in-use, non-reversed, substantially level, orientation on a rear mounted excavator arm of an excavator, whereby the front 16 of the coupler 10 points towards the cab of the excavator, the rear 18 of the coupler 10 points away from the cab of the excavator, and wherein the upper portion 12 of the coupler 10 is located above the lower portion 14 of the coupler 10.

The upper portion 12 is for connecting onto the excavator arm of the excavator. For that purpose, two pairs of holes 20 are provided, although only hole one of each pair of holes is shown due to the view being an elevation. The upper portion is also shown to be displaced slightly forward relative to the lower portion 14.

Those pairs of holes 20 are provided in sidewalls of the coupler 10. They are therefore spaced apart and they allow the coupler 10 to be attached to the excavator arm of the excavator (not shown) by using a pair of attachment pins (not shown). Such an attachment is conventional in the art, and thus needs no further discussion.

The lower portion 14 of the coupler 10 is for coupling to an accessory, such as an excavator bucket. In this illustrated embodiment the lower portion 14 has a pair of jaws 22, 24 and a pair of movable components 26, 34 that together latch a pair of attachment pins 52, 54 of the accessory (not shown) into the jaws 22, 24 of the coupler. This type of connection is also conventional -the rear jaw 22 is a downwardly facing jaw and the front jaw 24 is a forwardly facing jaw, and the process of attachment involves the following steps: 1. Locate the first, or front, attachment pin 52 of the accessory within the front jaw 24 of the coupler.

2. Swing the second, or rear, attachment pin 54 of the accessory into the rear jaw 22 of the coupler from below.

3. Prevent that second pin 54 from swinging out of the rear jaw 22 by powering a powered latch (the second movable component 26) into a latching position at least partially across the mouth of rear jaw 22.

As is also conventional, the illustrated powered latch is a pivoting latching hook 26 that is mounted for pivotal rotation about a pivot pin 28. Further, that latching hook 26 is adapted to be driven into that latching position by a hydraulic ram 32. However, a pneumatic ram or a screwthread drive, or some other known drive device, might alternatively be provided for the same purpose.

Instead of a pivoting latching hook 26, it is also known to use a non-pivoting, sliding latch mechanism.

Although the above features are conventional, the illustrated embodiment of the present invention is distinguished over prior art couplers by the specific design of various elements, such as I. the non-pin-engaging surface of the pivoting latching hook 26, .2 the provision of a novel secondary latching mechanism -the first movable component 34, and 3. by the distinctive mode of interaction between the first movable component and the second movable component (the powered latch 26).

The interaction between the first and second movable components 34, 26 is designed to prevent inadvertent, or non-deliberate, or premature, disengagement of the accessory from the coupler 10, but while still allowing, without undue burden, a deliberate disengagement of the accessory from the coupler. The arrangement also is designed to prevent such an undesired disengagement even in the event of a failure of the hydraulic ram (whereupon the pivoting latching hook might release itself, but whereupon the first movable component 34 will still lock the accessory onto the coupler), or in the event of a failure of one of the jaws/latches (the other jaw will still hold onto the accessory).

The first movable component 34, in this illustrated embodiment, is another pivotable member. It is mounted for rotation about a further pivot -second pivot pin 40. Like the first pivot pin 28, the second pivot pin 40 is fixed relative to the frame of the coupler 10.

The first movable component 34 provides a latch for the front jaw 24. For that purpose it consists of two components: 1. A first latch component 36 is provided to selectively provide an at least partial closure of the front jaw 24 of the coupler 10. It does that by selectively extending at least part way across the mouth 30 of the front jaw 24. Its actual position across the mouth, however, depends upon the orientation of the first movable component 34 relative to the frame of the coupler 10.

2. The second component is a second latch component -the arm 38. It is provided to extend from the second pivot pin 40 towards the second movable component 26. It is long enough to bear against that second movable component 26 when the coupler is in a normal, non-inverted orientation. However, it is heavier than the first latch component, whereby in an inverted orientation, i.e. if the coupler 10 is inverted, it will cause the first movable component 34 to rotate into a position in which the latch is closed. Thus an accessory cannot be decoupled from the coupler 10 while the coupler is inverted -a further safety feature. However, in the normal, in-use, orientation, the coupler is not inverted. Thus the arm 38 will usually engage against the second movable component 26, as shown.

Whereas the first latch component 36 is shown to be a straight sided member that pivotally descends from the second latch component or arm 38, the arm 38 of this first embodiment is shown to have a more convoluted shape for its underside 56. That underside 58 has a depressed area 58, which cuts upwards relative to the frame. That depressed area 58 is shown to be radiused. The underside 58 also has a nib area 60 that is distal of the depressed area 58. It also drops down from the base of the depressed area 58. Finally, the underside 56 has a chamfered end area 62 that ascends again from the nib area 60. The chamfered end area 62 is angled to face approximately rearwardly, but also slightly downwardly, such that it faces towards the pivoting latching hook 26.

Transitions between these three areas 58, 60, 62 are also shown to be smooth, i.e. radiused (preferably with a radius of no less than 2mm). This allows for a smooth engagement between the first and second movable components 34, 26 as they move/pivot relative to one another during the operation of the working mechanism.

The pivoting latching hook, i.e. the second movable component 26, has a conventional pin-engaging surface 64 that faces away from the arm 38 of the first movable component 34. That pin-engaging surface 64, being conventional, will not be described further, other than to identify its preferred upturned nib 66 for providing added security. Its other, arm-facing, surface 68, however, will be described.

The arm-facing surface 68 of the pivoting latching hook 26 curves from a straight shank 70, through a curved region 72 to a further upturned nib 74. The further upturned nib 74 has a radiused tip. Preferably that tip has a radius of no less than 5mm. The depressed area 58 of the underside of the arm then has a preferred radius of no less than 10mm, i.e. twice the radius of the radiused tip of the further upturned nib 74.

The further upturned nib 74 is adapted to be borne against by the underside 56 of the arm 38 of the first movable component 34. As such, it is important that the two bearing surfaces have no inter-engageable sharp edges, whereby they can slide relative to one another without jamming.

During respective pivoting of the two movable components 34, 26 between a super- extended position of the pivoting latching member 26 (as shown in Figure 1) and a non-latching position of the pivoting latching member 26 (as shown in Figure 3, albeit for a later part of the accessory attachment sequence), the further upturned nib 74 will follow the following three-stage path along the underside 56 of the arm 38: Stage 1. The further upturned nib 74 of the second movable component will initially be engaging the chamfered end area 62 of the arm 38, whereby first latch component 36 is in its most raised position relative to the first haw 24 (see Figure 1).

This position for the second movable component 26 is called the super-extended position since it is a position beyond which an attachment pin would be secured within the rear jaw 22.

The angle of the chamfer on the chamfered end area 62 of the arm 38 provides two functions. First it is such that any reaction force applied to that arm 38, at that end area 62, by the further upturned nib 74, is directed to pass above the pivot pin 40 of the first movable member 34. As a result the second movable component 26 can lift the arm 38 as the second movable component 26 moves further forwardly, i.e. away from its super-extended position, towards a normal latching position (see Figure 4, albeit again an illustration of a later part of the accessory attachment sequence). Secondly the chamfer allows a rapid sliding of the upturned nib 74 along the chamfered end area 62 (rapid relative to the degree of motion of the second movable component 26), whereupon the arm 38 will be lifted quickly, and the first latch component 36 will thus be rapidly extended at least partially across the mouth of the front jaw 24 for closing it.

Stage 2. Eventually the further upturned nib 74 will pass off the chamfered end area 62 of the arm 38 and onto the nib area 60 of the arm 38. That nib area 60 is angled almost perpendicular to the chamfered end area 62 (preferably an included angle of approximately 110°). As a result, further forward movement of the second movable component 26 (towards the non-latching position of Figure 3) will cause a slower rate of upward movement of the arm 38 than before. However, the front jaw has already been closed following the earlier movement of the arm 38, whereby this slow-down does not affect the closed status of the front jaw 24 (the rapid initial closure, therefore, is advantageous).

This slowing down of the movement of the arm 38 in response to further movement of the second movable component 26 has the added benefit also of preventing any attempt to lift the first latch component 36 (e.g. by a pin 52 attempting to exit the front jaw 24) from resulting in a sufficient force being transferred to the second movable component 26, via the arm 38, for allowing such a lifting of the first latch component 36 to occur.

This "gearing" effect is particularly desirable since it gives yet another safety mechanism to the coupler.

Stage 3. Next, the upturned nib 74 passes from the nib area 60 into engagement with the depressed area 58. At this point of the movement of the second movable component 26, the further movements of that second movable component 26 have a large upwards component. Therefore, to prevent that from resulting in a correspondingly large upwards movement of the arm 38, the depressed area 58 is provided in the underside 56 of the arm 38 to accommodate that upward movement of the nib 74. That therefore permits a further length of travel for the second movable member 26 than would otherwise be achievable. That in turn result a wider range of pin spacings (on the accessories) to be accommodated by the coupler.

As explained above, therefore, the engagement of the arm 38 of the first movable component 34 against the second movable component 26 allows the movementirotation of the first movable component 34 to be controlled by the movementlrotation of the second movable component 26. The second movable component 26 is thus operably associatable with latch for the front jaw 24 both for selectively closing the front jaw 24 for securing an attachment pin 52 within that front jaw 24, and for selectively opening the front jaw 24 for releasing an attachment pin 52 from within that front jaw 24. The opening of the front jaw 24, however, is only achieved, as described above, by locating the second movable component 26 into its super-extended position.

In an variation (not shown) the nib area 60, and the depressed area 58, can have a combined shape, or orientation, that in that position of the arm 38 shown, for instance, in Figure 4), either approximately follows the arc of rotation defined by the further upturned nib 74, or lies substantially tangential thereto, whereby, briefly, or for that remaining extent of travel of the second movable component 26, the further rotation of the second movable member 26 will cause only a very slight, or no, movement of the arm 38. The illustrated embodiment, however, is oriented more forwardly than that (relative to the frame), such that further upward movement of the arm 38 will still continue in response to the movement of the second movable component 26 during the second and third stages of the relative, interactive movements, albeit only at the slowed rate.

From the above it will be apparent that for coupling an accessory onto the coupler, the following procedure is carried out, as illustrated by the sequence of Figures 1 to 4: The second movable component 26 is moved into its super-extended position to open the front jaw 24. The coupler 10 is then manipulated with the excavator arm to locate a first attachment pin of the accessory into the first jaw. The coupler is then curled relative to the partially engaged accessory, using the excavator arm, to locate the second attachment pin into the rear jaw 22 of the coupler. The second movable component 26 is then powered into its normal latching position to latch the second attachment pin with the rear jaw 22. The attachment is now attached securely to the coupler.

The method of detaching that attachment from the coupler is then substantially a reversed procedure, as illustrated by the sequence of Figures 5 to 7: The second movable component 26 is powered to move it into a non-latching position for releasing the attachment pin located within the rear jaw. The coupler is then curled relative the accessory, using the excavator arm, to swing the attachment pin out of the rear jaw 22.

The second movable member is then powered in the opposite direction into its super-extended position, a position lying beyond its previous latching position, while the coupler is maintained in a normal, in use, orientation, whereby the latch for the first or front jaw 24 is moved from its latching position into a non-latching position (in which position the first jaw 24 is "open". The coupler is then manipulated relative to the accessory, using the excavator arm, to remove the first attachment pin from the first jaw 24 through the mouth of the first jaw 24. The accessory is now removed from the coupler.

Referring finally to Figure 8, alternative designs for both the second movable component 126 and the first movable component 134, are illustrated. The operation of the coupler, however, is identical.

In this alternative embodiment, the arm 138 of the first movable component 134 has a different underside 156 to that of the embodiment of Figure 1. The underside 156 has a flatter profile, and no distinct depressed area. Further, the arm-facing surface 168 of the second movable component 126 has a longer, flatter curvature. It does still end, however, at a nib 174 for engaging the underside 156 of the arm 138.

During the range of interactive motion of the respective first and second movable components 134, 126, the point of contact between the arm 138 and the arm-facing surface 168 is not always the nib 174. Instead, at a certain point of that range of motion (not illustrated), the point of contact transfers between the nib 174 of the second movable component 126 to the nib 176 provided at the end of the underside 156 of the arm 138. It will be readily apparent, however, that this second embodiment otherwise operates in the same manner as the first embodiment. For example is still requires the use of the super-extended position for the second movable component 126 for opening the front jaw 24.

Various aspects of the present invention have therefore been described above. Those aspects are described above, however, purely by way of example. Modifications in detail, however, can still be made within the scope of the invention as defined in the claims appended hereto. In particular, elements of one aspect or embodiment might be combined with elements of the other aspects or embodiments, and vice versa, as would be appreciated by a skilled person.

Claims

CLAIMSI. A coupler for attaching an accessory to an excavator arm of an excavator, the coupler comprising: a frame, a first moveable component that provides a latch that is associated with, and that is adapted to close, at least partially and selectively, a first jaw, the jaw forming a first half of a first part of an accessory connection between an accessory and the coupler, a second movable component that forms a part of a first half of a second part of the accessory connection, and a drive means for moving the second movable component relative to the frame between a latching position and a non-latching position, wherein the first movable component is interactable with the second movable component, such that movement of the second movable component from a latching position into a non-latching position causes movement of the latch, that movement of the latch either causing the closing of the jaw or causing a further closing of the first jaw; characterised in that: the first movable component can selectively bear against the second movable component at a point of contact for allowing that interactive movement to occur, but wherein the first movable component is not linked or joined to the second movable component at that point of contact.
2. The coupler of claim 1, wherein the first movable component is gravity operated, whereby it is gravity that causes the first movable component to bear against the second movable component.
3. The coupler of claim I or claim 2, wherein the geometry of the first movable component relative to the second movable component is such that the first movable* component will not jam against the second movable component in such a manner that the first movable component would block the movement of the second movable component.
4. The coupler of any one of the preceding claims, wherein the first movable component has bevelled, rounded or smoothly profiled surfaces that can maintain engagement against the second movable member throughout the full range of interactive movement therebetween.
5. The coupler of any one of the preceding claims, wherein the geometry of the respective movable components is such that there can be no over-centering orientation of the components, relative to any of their axes of rotation and themselves, during the ranges of interactive motion experienced by them during use of the coupler.
6. The coupler of any one of the preceding claims, wherein one or more rotation stop is provided to limit the respective ranges of rotation or movement of either or both of the first or the second movable components.
7. The coupler of any one of the preceding claims, wherein the first jaw is formed in the frame of the coupler.
8. The coupler of any one of claims I to 7, wherein the first jaw is formed as a separate component and it is welded to, or otherwise joined to, the frame of the coupler.
9. The coupler of any one of the preceding claims, wherein the first jaw is formed from hardened steel.
10. The coupler of any one of the preceding claims, wherein the second movable component is biasable or movable into a latching position by a hydraulic ram.
11. The coupler of any one of the preceding claims, wherein the second movable component is associated with a second jaw.
12. The coupler of any one of the preceding claims, wherein the second movable component is a pivoting latching hook.
13. The coupler of any one of claims 1 to 11, wherein the second movable component is a sliding latch or plate.
14. The coupler of claim 12, wherein the pivoting latching hook has a first, rearwardly-facing, surface for engaging an attachment pin of the accessory.
15. The coupler of claim 12 or claim 14, wherein the hook has an upturned lip at its free end.
16. The coupler of any one of the preceding claims, wherein the first jaw of the coupler is spaced away from the second movable component and it points forwards relative to the frame.
17. The coupler of any one of the preceding claims, wherein a second jaw is provided, that is associated with the second movable component, the second jaw pointing downwardly relative to the frame.
18. The coupler of claim 17, wherein the second jaw has a mouth that is at least 50% wider than the mouth of the first jaw.
19. The coupler of any one of the preceding claims, wherein the latch formed by the first movable component comprises a first latch component and a second latch component, the first latch component being for providing the at least partial closure of the first jaw, and the second latch component extending towards the second movable component.
20. The coupler of claim 19, wherein the second latch component extends towards the second movable component from a pivot point located between the first and second latch components.
21. The coupler of claim 19 or claim 20, wherein the second latch component is the component of the first movable component that can selectively engage against the second movable component.
22. The coupler of claim 21, wherein the engagement is a direct engagement.23. The coupler of any one of claims 19 to 22, wherein the two latch components are unitarily formed.
23. The coupler of any one of claims 19 to 22, wherein the two latch components are separately formed components that are connected together.
24. The coupler of claim 23, wherein the two latch components are pivotably connected together.
25. The coupler of any one of claims 19 to 24, wherein the first latch component extends generally downwards relative to the frame.
26. The coupler of any one of claims 19 to 24, wherein the second latch component extends generally rearwards relative to the frame.
27. The coupler of any one of the preceding claims, wherein the latch formed by the first movable component is mounted about a pivot for pivotal rotation relative to the frame of the coupler.
28. The coupler of claim 27, wherein the pivot is fixed relative to the frame.
29. The coupler of any one of the preceding claims, wherein the surface or surfaces of the first movable component that engage the second movable component, and the surface or surfaces of the second movable component that engage the first movable component, engage each other throughout the ranges of interactive motion of the two respective components such that any reaction force therebetween is directed above a pivot axis of the first movable member so as not to cause an over-centering of the first movable component relative to its pivot point, whereby the first movable component will always respond to applied force from the second movable component by tending to rotate about its pivot point, rather than jamming against the second movable component.
30. The coupler of any one of the preceding claims, wherein the first jaw has a mouth, and a widened interior compared to the mouth of the jaw.
31. The coupler of any one of the preceding claims, wherein the back of the front jaw defines a radiused throat.
32. The coupler of claim 31, wherein the radiused throat of the first jaw has two or more different, but distinct, radiused portions for accurately seating two or more different attachment pins, the attachment pins having different radiuses.
33. The coupler of any one of the preceding claims, wherein the point of interaction between the two movable components is not a fixed point of interaction over the range of interactive motion of the two movable components.
34. The coupler of any one of the preceding claims, wherein the point of interaction between the two movable components does not have a fixed pivot axis relative to the frame over the range of interactive motion of the two movable components.
35. The coupler of any one of the preceding claims, wherein the point of interaction between the two movable components does not have a fixed pivot axis relative to the first movable component over the range of interactive motion of the two movable components.
36. The coupler of any one of the preceding claims, wherein the point of interaction between the two movable components does not have a fixed pivot axis relative to the second movable component over the range of interactive motion of the two movable components.
37. The coupler of any one of the preceding claims, wherein there is more than one point of contact between the first and second movable components during at least part of their full range of respective movements.
38. The coupler of any one of the preceding claims, wherein the second movable component has a latching face that faces a first direction, for engaging against an attachment pin of an accessory, and a second face that faces away from that latching face that faces towards the first movable component.
39. The coupler of claim 38, wherein the second face includes a curve against which an end of the first movable component may bear during at least part of the range of interactive motion of the two movable components, the curve being for sliding along during certain respective interactive movements of the first and second movable components.
40. The coupler of claim 38 or claim 39, wherein the second face has an upturned nose.
41. The coupler of any one of the preceding claims, wherein the first movable component is a pivotal member, mounted to the frame about a further pivot defined by a second pivot pin, which pin is spaced from the second movable component.
42. The coupler of claim 41, wherein an arm extends from the second pivot pin towards the second movable component for engaging against the second movable component.
43. The coupler of claim 42, wherein the arm's free end has an underside with a contoured surface against which the second movable component will bears during the interactive motion of the two movable components.
44. The coupler of claim 43, wherein the contoured underside includes a depression for accommodating an upturned nose of the second movable component during at least part of their respective interactive ranges of travel.
45. The coupler of any one of the preceding claims, wherein the second movable component is adapted to be moved beyond a normal latching position into a super-extended position, and wherein in the super-extended position, as a result of the interaction between the two movable components, the first movable component has moved into a latch release position in which the latch for the first jaw has opened sufficiently to allow an attachment pin to exit through the mouth of the first jaw.
46. The coupler of any one of the preceding claims, wherein a hinged gate is provided in the latch for allowing an attachment pin to be inserted into the first jaw, through the mouth, past the latch, when the jaw is closed by the latch.
47. A coupler substantially as hereinbefore described with reference to Figures 1 to 7.
48. A coupler substantially as hereinbefore described with reference to Figure 8.
49. A method of attaching an accessory to a coupler on an excavator arm of an excavator, the method comprising: a) providing an excavator with a powered excavator arm, the arm having a coupler on an end thereof, the coupler comprising two latches and at least a first jaw, the first jaw being associated with a first of the latches, and the second latch being a powered latch, powered for movement between a non-latching position, a latching position and a super-extended position, the first latch being moveable into a latching position by the powered latch as the powered latch is powered from a super-extended position, and the first latch being moveable from a latching position into a non-latching position to open the jaw by powering the powered latch beyond a normal latching position into the super-extended position while the coupler is in a normal, in use, substantially level, orientation; b) providing an accessory with two attachment pins thereon sized and spaced to fit onto the coupler by engagement of one pin with the first jaw of the coupler and the other pin with the powered latch of the coupler; c) manipulating the coupler with the excavator arm to locate a first attachment pin of the accessory into the first jaw; d) curling the coupler relative to the partially engaged accessory with the excavator arm for locating the second attachment pin into a position for engagement by-the powered latch, and powering the powered latch towards a normal latching position to latch the second attachment pin with the powered latch.
50. The method of claim 49, further comprising the step of powering the powered latch to move it into the super-extended position to open the first jaw prior to locating the first attachment pin within that jaw, and the step of powering the powered latch to move it from its super-extended position to at least partially close the first jaw with the first latch prior to locating the second attachment pin into a position for engagement by the powered latch.
51. The method of claim 49 or claim 50, carried out using the coupler of any one of claims 1 to 48.
52. A method of detaching an accessory from a coupler on an excavator arm of an excavator, the method comprising: a) providing an excavator with a powered excavator arm having a coupler on an end thereof, the coupler comprising two latches and at least a first jaw, the first jaw being associated with the first of the latches, and the second latch being a powered latch, powered for movement between a non-latching position, a latching position and a super- extended position, the first latch being inoveable from a latching position into a non-latching position by the powered latch while the coupler is in a normal, in use, substantially level, orientation; b) providing an accessory that is connected to the coupler, the accessory having two attachment pins thereon that are sized and spaced such that a first pin is engaged with the first jaw of the coupler and the second pin is engaged by the powered latch of the coupler, the powered latch being in the latching position; c) powering the powered latch to move the powered latch into a non-latching position to release the second pin from the powered latch; d) curling the coupler relative the accessory with the excavator arm to swing the second pin away from the path of powered latch; e) powering the powered latch beyond its previous latching position into the super-extended position, that extended movement of the powered latch into the super-extended position, while the coupler is in a normal, in use, orientation, causing the first latch to be moved from its latching position into a non-latching position in which the first jaw is open; and manipulating the coupler relative to the accessory using the excavator arm to remove the first attachment pin from the first jaw of the coupler.
53. The method of claim 52, carried out using the coupler of any one of claims 1 to 48.
54. A method of attaching an accessory to a coupler on an excavator arm of an excavator substantially as hereinbefore described with reference to the drawings.
55. A method of detaching an accessory from a coupler on an excavator arm of an excavator substantially as hereinbefore described with reference to the drawings.