GB2515262A - A coupler with an actuator arrangement for controlling front and rear latches - Google Patents

Abstract

A coupler comprises a first jaw 54 with a movable first latch 74, a second jaw 52 and hook latch 64 having a retracted position and at least one advanced position, and a blocking member 100. The coupler further comprising an actuator arrangement comprising two linked hydraulic actuators 78 & 80. The first of the actuators 78 is for selectively moving both the blocking member 100 and the first latch 74 and a second of the actuators 80 being for selectively moving the second latch 64, wherein the hydraulic link is such that activation of hydraulic pressure in the actuator arrangement in a manner intended for causing a retraction of the second actuator, for retracting the second latch towards the second latch's retracted position, also causes an actuation of the first actuator to extend that first actuator so as to move at least the first latch into its non-latching position.

Description

I

A COUPLER WITH AN ACTUATOR ARRANGEMENT FOR CONTROLLING

FRONT AND REAR. LATCHES The present invention relates to an actuator arrangement for a hydraulic coupler with front and rear latches for coupling a two-pin accessory to an excavator arm of an excavator. One such accessory could be an excavator bucket, The invention also relates to a coupler with such an actuator arrangement.

Couplers for coupling accessories to the excavator arm of an excavator are well known in the art, and many use hydraulic actuators to control at least one latch thereon. Indeed many prior art patents and patent applications describe such couplers. See, for example, GB2330570, GB2177674, EPU 184282, US200S 169703, T.JS6699001, W020 101059948, G82412361, G32463 158, GB2447809 and W02008/03 1590.

The couplers gcncrally comprise a top half that is connectable to an excavator arm using two attachment pins (via two pairs of holes provided for those attachment pins) and a bottom half for engaging two further attachment pins, on the accessory. For that latter purpose that bottom half typically comprises two jaws, rather than holes. Those jaws engage respective ones of those two further attachment pins of the accessory.

A common feature of many such excavator couplers is that one of the two jaws is usually referred to as a front jaw. Its opening (for receiving a first or front one of the two further attachment pins) is generally directed out of the front end of the coupler, i.e. generally parallel to an imaginary line joining the two pairs of holes in the top half of the coupler.

Sometimes it is angled slightly from that line, usually upwards, perhaps at an angle of tip to 15°.

The second law is then usually referred to as a rear jaw. It generally points downwardly, i.e. in a direction that is generally perpendicular to the front jaw, or the imaginary line between the two pairs of holes.

The rear jaw commonly has an associated latching member -usually a hook or plate.

The latching member can be slid or pivoted between a latched position and an unlatched position. In the latched position, the opening of rear jaw is at least paruaUy closed by the latching member. In the unlatched position, however, the latching member is usually thuly retracted out of the jaw so as to leave the jaWs opening open so that the attachment pin can be removed from the jaw downwardly. Sometime, however, it is enough just to retract it out of the way of the attachment pin.

Secondary locking devices are also often provided for these couplers. For example, the coupler in GR2330570 also features a blocking bar which is adapted to fall under the influcncc of gravity (when in normal, in-use, orientations of the coupler, i.e. non-inverted orientations) into a blocking position in front of the latching member -in this case a latching hook. In that blocking position, the blocking bar will resist the unlatching of the latching hook by blocking its path from its latching position into an unlatched position.

The blocking bar is pivotally mounted about a pivot. That pivot is positioned near the front jaw. The blocking bar therefore points generally towards the rear jaw from that pivot and is balanced about that pivot such that gravity will usually urge it towards its blocking position, i.e. while the coupler is in the normal, in-use, orientations, i.e. rather than upside down or partially inverted. Then, in order to unblock the latching hook (for decoupling the accessory from the coupler), either the coupler would need to be inverted or else sonic fomi of urging means would be provided for lifting the blocking bar from its blocking position into a non-blocking position. One such urging means could be a small hydraulic ram.

During ilooTtal LLSC, ic. when digging with a bucket, very high forces can he loadcd onto the latching hook by the attachment pins ci the accessory. Occasionally those forecs may be transferred, at least in part, onto the blocking bar. In order to cope with those forces, therefore, the blocking bar is usually a rather substantial element. This is to prevent the blocking bar from buckling tinder those occasional loads.

Other couplers are disclosed in 1JS6699001 and 0B2447809. Tn those documents, the rear pivoting latching hook is replaced by a sliding member, Further couplers are disclosed in GB2463 158 and W02008/03 1590. In those couplers, both jaws feature a pivotable latch, whereby two latching members arc provided.

The movement of the latches can be by a spring bias, or by a mechanical actuator (usually either a hydraulic rain or a large screwthrcad drive), or in sonic cases by gravity e.g. the front latch in GB243 1322. The movement of the blocking bar, where provided, can also be by actuator or gravity. For the actuator, it is typically a separate hydraulic ram to the ram for the rcar latch.

Due to the configuration of the elements of the various moveabic components in these couplei.'s, the latching and securing actions for attaching an accessory to the coupler (on the end of an arm of an excavator), and also the later detachmenVdisconncction actions for removing said attachment therefrom, typically have to he performed using a series of predefmed steps since the mechanisms such as thc latches for each jaw, and any blocking means provided therefor, are designed so as not to allow them all to be easily actuated together. This is important so as to prevent inadvertent detachment, or to ensure appropriate attachment -an inconect attachment can result in an unexpected detachnent, or damage to the components of the coupler. What would he desirable, however, would be to provide a coupler, or a system involving a coupler, in which both jaws arc able to secure a respective pin, and in which both jaws can be opened or closed through a simple set of prcdefincd steps, respectively for the detachment and attachment procedures According to the present invention there is provided a coupler for attaching an accessory to an excavator arm of an excavator, the coupler comprising a. first jaw with a movable first latch, a second latch having a retracted position and at least one advanccd position, and a blocking member for selcetiye interaction with the second latch via a movement between a non-blocking position and at least one blocking position, such selective interaction being such as to resist movement of the second latch fiom the appropriate at least one advanced position into the retracted position when the blocking member is in the appropriate at least one blocking position, the coupler further comprising an actuator arrangement comprising two linked hydraulic actuators for connection to a pair of hydraulic fluid feed or rctuin lines, a first of the actuators being for selectively moving both the blocking member and the first latch and a second of the actuators being for selcctivcly moving the second latch, wherein the link between the two hydraulic actuators is a hydraulic link such that activation of hydraulic prcssurc in the actuator arrangement in a manner intended for causing a retraction of the second actuator, for S retracting the second latch towards the second latch's retracted position, also causes an actuation of tIm first actuator to extend that first actuator so as to move at least the first latch into its non-latching position.

Preferably that activation of hydraulic pressure also moves the blocking member into non-blocking position.. However, that movement is subject to the blocking member not being otherwise prevented from such movement by a secondary blocking mechanism.

The blocking member and the first latch arc arranged preferably to be moved together.

Alternatively they might he weighted or otherwise biased to move in turn.

Preferably the first actuator is associated with a check valve such that the first latch will lock into a non-latching position when hydraulically moved thereto by that activation of hydraulic pressure.

Preferably the cheek valve is mounted on a hydraulic manifold of the second activator, the manifold then also preferably has a port for connection of a third hydraulic fluid feed and return line for connecting the first actuator thereto, Preferably the check valve is hydraulically connected to the actuator assembly such that activation at' hydraulic pressure in the actuator anangcment in a manner intended for causing an extension of lie second actuator will release or hold open the check valve such that the first actuator is free to retract, e.g. under a biasing force such as a spring therefor. This then allows the first latch and the blocking bar to default to a latching and blocking position, respectively, i.e. for them not to be held in lifted positions by the check valve.

Preferably the first actuator connects to only a single hydraulic fluid feed and return line, i.e. the third hydraulic fluid feed and return line. Fluid thus flows in either direction through that line -as a feed to the fast actuator when extending that actuator, and as a return when the lust actuator is retracting.

Preferably the manifold also has connection points for the pair of hydraulic fluid feed or return lines. Preferably the manifold then also has a pair of hydraulic fluid connection pipes extending to a head manifold of the second actuator.

Preferably the head manifold comprises a check valve of the second actuatol; the second actuator then being otherwise a conventional dual-action hydraulic cylinder as commonly found in excavator couplers, thus allowing hydraulically powered extension via a hydraulic fluid pressure feed from a first of two hydraulic fluid connection pipes, rjth expelled fluid from the cylinder then returning through the other of the connection pipes, and a hydraulically powered retraction through the other of the connection pipes being the pressure feed and the first Pipe then instead being the return pipe. Preferably these connection pipes arc the ones to the hydraulic mani Ibid described above.

Preferably the hydraulic flow path to the second actuator for extending the second actuator ha.s a greater resistance to fluid flow than the hydraulic connection thereto for the check-valve of the first actuator such that the check valve for the first actuator will open before the second actuator starts to extend, This might be provided by a narrow fluid pathway in the hydraulic manifold at the point that it connects to one of the connection pipes, or by a restriction or narrow pipe elsewhere along that fluid pathway to the second actuator.

Preferably either or both of the blocking member and the first latch are arranged to move prior to the movement of the second latch into its retracted position.

The blocking member provides a first precautionary and effective, but otherwise generally redundant, latch back-up mechanism that can prevent inadvertent detachment upon a failure of an element within the coupler, such as the actuator for the second latch -a free-swinging second latch cannot retract to release its attachment pin. since the blocking member will typically lie in the path of such a retraction.

The first latch provides a second precautionary and effectivc, but otherwise generally redundant, latch buck-up mechanism that can prevent inadvertent detachment upon a thilure of an element within the coupler, such as the second latch -should the second latch fail, i.e. if the attachment pin fails to he secured by it, then the other attachment pin S within the first jaw), will be retained in that first jaw by the first latch.

Preferably the coupler comprises a third precautionary and effective, but otherwise generally redundant, latch back-up mechanism that can prevent inadvertent detachment upon a failure of an element within the coupler. This third latch back-up mechanism may he the shape of one or both latches. For example, the second latch may he in accordance with the hook defined in GB2330569, the whole contents of which are incorporated herein by reference, Preferably the hook's nose is thus upturned to resist an inadvertent release of an accessory pin from the hook in the event of a main actuator failure. After all, that will allow thc hook to resist the exiting of a pin from the hook if that hook becomes free to rotate about its pivot.

Alternatively, or additionally, the third (fourth, ete) back-up mechanism may be a secondary blocking member ari.anged selectively to resist movements of the blocking member from one or each of the at least one blocking positions into its non-blocking position.

Preferably the secondary blocking member is a free-swinging hook, attached to the blocking bar, and adapted to selectively catch. on a pin of the frame as disclosed in GB24825 15, the,x,rhoIe contents of which are incorporated herein by way of reference.

Alternatively it might be a flee-swinging member mounted to the frame that can engage the upper side of the blocking bar as disclosed in GB 1220135.6, the whole contents of which are also incorporated herein by way of reference. As such, it might assume one of a plurality of blocking positions, depending upon which of the at least one blocking positions is assumed by the blocking member. These positions may be determined or acquired by virtue of stepped surfaces on either the blocking member or the secondary blocking member, or both.

Preferably the lirst jaw is the front jaw, the first latch is the front latch and the second latch is the rear latch.

Preferably the first jaw has an opening that faces along a generally longitudinal axis ol the coupler.

Preferably the second latch is associated with a second jaw. Preferably the second jaw faces a direction that is peipendicular to that of the first jaw, e.g. it may he generally downwards facing, compared to a forwards facing first jaw, Preferably the first and second jaws have openings for receiving the attachment pins and the opening of the second jaw, when measured perpendicular to the direction of entry into the jaw, is at least 1.5 times wider than the opening of the first jaw.

Preferably the two latches are not opened simultaneously, but instead one alter the other.

Preferably the first latch is pivotable between its latching position and its non-latching position.

Preferably the first latch at least partially closes its associated jaw when in its latching position.

Preferably the second latch at Icast partially closes an associated second jaw when in its advanced position.

Prelei-ably the accessory couples to the coupler by a two-pin attachment, wherein the first jaw engagcs a first one of those two pins aiid the second latch engages the second of those two pins, the second latch cooperating with the frame and the first jaw to provide the engagement force for retaining the first pin in the first jaw and the second pin against the second latch.

Preferably the mode of attachment includes first engaging the first pin in the first jaw, and then engaging the second pin with the second latch Preferably the second jaw faces a diffcrent direction to the first jaw. Preferably the second jaw faces a direction that perpeiicutar to the direction of the first jaw.

Preferably the second jaw has a wider opening than the first jaw -this allows for accessories from different manutheturers to be accommodated -pin diameters of the attachment pins, for a given application/machine load rating, tend to be generally similar, i.e. rarely differing by more than 5%, bitt pin centre spacings can vary wore than that, e.g. often by up to 1 5% between manufacturers.

The first and second latches may he pcrmanently or selectively biased towards their latching positions, as might be the blocking member -towards its one or more blocking positions, and the secondary blocking member likewise, although preferably it is only the first latch and blocking member that ale so biased. For that purpose the first actuator ire1eiably comprises a spring for biasing it towards a retracted state. The second actuator may instead have such a spring, but instead biasing the second latch/second actuator into the advanced/elongated state.

With the spring for the first actuator, that spring not only biases the first latch into a latching position -it also biases the blocking member towards its one or more blocking positions.

For the secondary blocking member a bias into a blocking state may he achieved or provided by gravity, e.g. when the coupler is appropriately oriented (e.g. with the rear jaw pointing downwardly), Jn another arrangement the bias may be permanent, such as by a spring.

The two actuators are in the form of hydraulic rams Preferably the first or front latch can be opened independent of movement of the blocking bar -e.g. to "click-on" a first pin of an accessory into the first or front jaw, even when the blocking bar is down in a blocking state for the second or rear latch.

Preferably the ram for the firsL latch and blocking member has a selectively operable oil circuit bypass, thereby allowing the front latch to be opened independent of movement of tile blocking bar e.g. to "click-on" a first pin of an accessory into the front jaw.

Preferably the rear jaw points directly away from the first (top) half of the coupler, i.e. it is a downwardly facing jaw.

Preferably the front jaw faces substantially forwards or generally longitudinally, i.e. generally along the long-axis of the coupler (or generally parallel to an imaginary line 1 0 extending between the centres of the two attachment pins of the accessory -once correctly mounted onto the coupler), The front jaw in further arrangements may face slightly off that longitudinal line, preferably upwards, but preferably by no more than From that line.

Preferably the accessory is an excavator bucket.

Preferably the first latch is merely a generally redundant back-up mechanism for the coupler, the second latch and first jaw providing the primary latching mechanism for the accessory to the coupler. As a redundant back-up mechanism, the first latch selves to secure the accessory to the coupler in the event of a failure in the primary latching mechanism, such as if the second latch bends or breaks off. As such, the first latch is unlikely actually to engage against an attachment pin that might be engaged within the first jaw, even though it latches that pin within that jaw.

Preferably the first latch ha.s a first pivot pin or pivot axis about which it can rotate, that pivot pin or pivot axis extending in a lateral direction relative to the.ftame of the coupler.

Preferably the first latch has a second pivot pin or pivot axis about which the first actuator can pivot as the actuator extends oa' retracts, or as the first latch rotates relative to the frame. Preferably the second pivot phi or pivot axis is non-coaxial but parallel to the first pivot pin or pivot axis.

Preferably the blocking member is mounted relative to the frame about a third pivot pin or pivot axis, whereby it pivots between its blocking and non blocking positions.

Preferably that pin or axis extends in a lateral direction relative to the flame of the coupler.

Preferably the blocking member has a fourth pivot pi or pivot axis about which the first actuator can pivot as the actuator extends or retracts, or as the blocking member rotates relative to the frame. Preferably the fourth pivot pin or pivot axis is non-coaxial but parallel to the third pivot pin or pivot axis.

Preferably the first actuator is attached to the blocking member and the first latch at its ends, by the second and fourth pivot pins or pivot axes, Preferably the second actuator is mounted relative to the frame at a first end thereof by a fifth pivot pin or axis, and a second end thereof is mounted to the second latch at a sixth pivot pin or axis.

Preferably the fifth pivot pin or axis is coaxial or common to the third pivot pin or axis, i.e. there may be a single pin defining both the third and fifth axes -a common axis, Preferably the second latch is mounted relative to the frame via a seventh pivot phi or pivot axis.

Preferably the seventh, pivot pin or pivot axis is directly above the rear jaw when that rear jaw is facing the downwards direction.

Preferably the upper wall of that jaw (with respect to that orientation) is convexly curved with a centre of rotation aligned with the seventh pivot pin or pivot axis.

The words first, second, third, fourth, ete, with respect to these pivot pins and axes are not intended in the limiting sense, i.e. there could be just two pivot pins or pivot axes, e.g. the first and third mentioned above, or the second and fourth, etc.. For example, sliding members, rather than pivoting latches, may remove the need for some of these pivot axes, Preferably there are at least till-ce spaced pivot pins or pivot axes extending through, and interacting with, both sidewalls of the frame of the coupler. The at least three spaced pivot pins or pivot axes are provided such that there is one for each latch and one for (lie blocking member and/or second actuator. Preferably there are at least three additional pivot pins a. pivot axes within the frame of the coupler, hut which do not interact with the sidewalls of the frame of the coupler -two being for the first actuator and one being for the second actuator.

Preferably the first latch is adapted for facilitating the click-on insertion of an attaclunent pin past the end thereof, e.g. past the end of its nose portion, in the event that the end is not fully moved into a non-latching position at the time of insertion of thc attachment 1 5 pin, For this purpose, the cnd may present an outwardly facing angled surface, or a rounded surface, angled with respect to the contact point thereof with the pin to allow the pin to force the end upwards due to the resulting angle of the reaction force generated thereby. Conversely, the internal facing surface of that first latch is arranged to impart a reaction force, upon engagement by a pin trying to exit the first jaw, that causes the first latch to be biased into ajaw closing position.

Preferably the rear end of the frame has a lifting eye on it, which lifting eye is advantageously ccntrally located. It may instead he aligned with a side plate, especially if the coupler is fabricated rather than cast.

PreI'erahly the Irame is a cast steel frame, rather than a fabricated frame (die latter typically meaning that it is one made from plate steel). however, a fabricated flame is also possible, especially on large capacity couplers, or low volume or customer specific products.

The front jaw may have a cut-out in its lower lip, the cut-out extending across the fill extent of the jaw, The tnit-out is to accommodate an attachment pin to provide a further resistance to a pin exiting the front jaw -due to the outer lip formed thereby.

The present invention also provides an excavator conipnsing such a coupler.

The invention also provides a method of using the coupler or excavator as herein described, comprising powering (lie actuator arrangement for extending the second actuator, whereupon the front latch adopts a latching state and the blocking bar drops to a blocking state. This is preferably achieved through a biasing force for the first actuator, that biasing force contracting the first actuator. Preferably the biasing force is provided by a spring. In preferred arrangements, the spring may be within or around th.e first actuator.

The invention also provides a method of using the coupler or excavator as herein described, comprising powering the actuator arrangement for retracting the second actuator, whereupon the front latch adopts a non-latching state and the blocking bar lifts to a non-blocking state. This is achieved through a hydraulic bias from the first actuator, that biasing frrce extending the first actuator.

-The present invention also provides an actuator arrangement for an excavator coupler, the actuator arrangement comprising two linked hydraulic actuators for connection to a pair of hydraulic fluid feed or return lines, a first of the actuators being for selectively moving both a blocking member and a fIrst latch of the coupler and a second of the actuators being for selectively moving a second latch of the coupler, wherein the lin.k between the two hydraulic actuators is a hydraulic link such that activation of hydraulic pressure in the actuator arrangement in a manner intended for causing a retraction of the sccond actuator, for retracting the second latch towards a latch retracted position, also causes an actuation of tile first actuator to extend that first actuator so as to move at least (lie first latch into a non-latching position.

The present invention also provides a coupler and a method of use thereof, comprising the above actuator arrangement.

These and other features of the present invention rjll now be described, by way of example only, wit.h reference to the accompanying drawings in which: Figure I shows a cut-away perspective view of a coupler incorporating the system of the present invention from a forward perspective (viewed generally from the front), The coupler is in a typical latching condition, although pins of an accessory are not shown; Figure 2 shows the coupler of Figure 1, in the same condition thereof, but as a side elevation. It illustrates the relative positions of the various components of this embodiment of coupler; Figure 3 shows a further cut-away perspective of the coupler of Figure 1, still in the same condition, hut now from a rearward perspective (viewed generally from the rear); Figure 4 shows the same coupler as before but in a first "rcar-latch-blocked" condition, wherein an actuator for the rear latch has powered up for retracting that latch, hut that latch has engaged a free end of a blocking bar, that blocking bat itself being blocked by a locking hook member depending therefrom and catching a peg on the frame of the coupler; Figure 5 shows a similar arrangement to Figure 4, but in which only the locking hook member is catching the peg; the rear hook has not retracted. This condition may occur upon inversion of the coupler in a non-crowding direction, if the weight of the blocking bar can cause it to lift; by inverting it in a non crowding direction, the locking hook rncmbcr will catch the peg, rather than rotate away from it.

Figure 6 shows another condition of the coupler, hut where the coupler was inverted into a crowd position before the actuator arrangement was powered into a frilly latch open condition. The coupler has then been reoriented ready to hook the front jaw onto an accessory -two pins (and the top -dotted lines) of which are shown schematically; both latches are open and the blocking bar is lifted; the crowd rotation displaced the locking hook member to allow lifting of the blocking bar; Figure 7 shows yet another condition of the coupler, where the latches are in their latching states, hut in which the rear latch is extended ifirther rearwardl.y than in Figure 2, it thus being in the position it might adopt for latching an accessory with a wider pin spacing than when in the condition of Figure 2. Again the pins are not shown, hut they will be similar to that of Figure 6; Figure 8 shows all embodiment of hydrau ic ram for use in the coupler of the preceding Figures; Figure 9 is a top plan view of that hydraulic Tam; Figure 10 is a side elevation of that tam with internal components and fluid pathways indicated in broken lines; Figure 11 is a rear elevation -viewed from the rear end -the end attached to the rear latch.

Figure 12 illustrates a hydraulic manifold, in front elevation, that in use is provided oil top of the tam, but shown here as a separate component to illustrate more clearly the apertures and fluid passageways located therein (the latter in broken lines); Figure 13 is sectional view X-X from Figure 12; Figure 14 is sectional view Y-Y from Figure 12; Figure 15 is a top plan view of the hydraulic manifold illustrating the apertures and fluid passageways located therein (the latter in broken lines); Figure 16 is a right side elevation of the hydraulic manifold illustrating the apertures and fluid passageways located therein (the latter in broken lines); Figure 17 is a rear elevation of the hydraulic manifold illustrating the apertures and fluid passageways located therein (the latter in broken lines); and Figure 18 is sectional view Z from Figure 17.

Referring first of all to Figure 19, an excavator 20 is shown. This excavator 20 has a cab 22 and an excavator arm 24 comprising a boom arm 26 and a dipper arm 28. The boom arm 26 is controlled by two primary hydraulic cylinders 30, each in this embodiment being mounted to the sides of the boom arm 26. Some excavators may have only one such cylinder, or more than two such cylinders.

Both primary hydraulic cylinders are provided to provide the main raising and lowering thnction for the arm, including lifting the dipper arm and thus also a coupler 32 and an accessory 34 (here in the form of an excavator bucket) coupled to the end of the dipper ann 28.

Movement of the dipper arm 28 relative to the boom arm 26 is controlled by a dipper aim cylinder 36, the extension and refraction of which rotates the dipper arm 28 relative tothehoomarm26.

Rotation of the coupler 32, and thus the accessory mountcd thereon, is controlled by a linkage arrangement 38 and a rotator cylinder 40.

The above features of the excavator are all fairly conventional and alternative excavator arrangements, in particular alternative geometries for the boom aim, the dipper arm and the linkage arrangement, are also well known in the art. The present invention can be used with any of these excavator arrangements.

To use the excavator, an operator sits in the cab 22 and operates controls therein. These controls include a coupler control unit 42. This coupler control unit 42 is linked to pressure sensors 44, or other sensors, for sensing the status of the primary hydraulic cylinders or the boom ann. In particular, in this embodiment they are for sensing whether the boom arm is in a condition that would be appropriate for allowing a coupling or decoupling procedure to be carried out with the coupler 32, via the coupler control unit 42. The coupler control unit 42 in this embodiment is additionally connected to an accelerometer 46 or tilt switch (or both), here in the dipper ann 28, which is designed to sense the status of the dipper arm 28. For example, the accelerometer or tilt switch can sense when the dipper arm is in a vertical orientation, i.e. 900 to the ground, and if the boom ann 26 is also suitably sensed to he not carrying the load of the dipper ann, coupler and accessory (such as by having the accessory on the ground), it is deemed that the excavator arm has been positioned into a condition ready for coupling or decoupling procedures. These featurcs are disclosed in further detail in GB 1220135.6, the whole contents of which are incorporated herein by way of reference, Referring next to Figures 1 to 7, another embodiment of coupler 32 is shown. It has a cast frame, with variable thicknesses in the frame members for providing a more lightweight design, whereas that of Figure 19 might he cast or fabricated.

This coupler 32, as is conventional, comprises a frame 48 with a top half 50 and a bottom half 52. The top half is for attaching to the excavator aim -through the linkage &rangeinent 38 of the dippcr aim 36 using attachment pins as shown in Figure 1. The 1 5 bottom half 52 is then for attaching to an accessory such as a bucket, as also shown in Figure 1.

For the attachment to the accessory, the bottom half features a first jaw -here the front jaw 54, and second jaw -here a rear jaw 56 (see Figure 2). The front jaw 54 opens generally along or parallel to the longitudinal axis 58 of the coupler 32, although it may instead be arranged at an angle thereto -typically no more than t5° therefrom, and usually pointing upwardly to minimise the likelihood of an accessory attachment pin 60 from accidentally falling out of that front jaw 54. The rear jaw 56 instead opens downwardly, or transverse to that longitudinal axis SR. This rear jaw is for a second attachment pin 62.

In use, the first attachment pin 60 will be the first pin to be captured by the coupler 32 (in the front jaw), with the second attachment pin 62 then being engaged up and into the rear jaw 56 by dropping the rear jaw down onto the second pin (when the latch is open-see Figure 6), prior to it then being engaged by the coupler's rear latch 64 as shown in Figure 2.

The fi'ont jaw 54 is providccl with a dual radiused throat -best seen in Fig land 4-such that. a normal aLtachment pin 60, as shown, can sit at the very real' of that throat, whereas a slightly larger attachment pin (e.g. ror a different manulactumr, or a different type of tool, or a tool with a higher load capacity) would instead also be able to be accommodated in the front jaw 54, but it would instead sit on the second radiused pai't 66 of that throat. This ensures compatibility with a wider range of accessories.

The rear jaw 56, on the other hand, is considerably wider than the diameter of the second attachment pin 62 in this embodiment. As can be seen in Figure 6, its opening is greater than twice the diameter of that attachment pin 62. This wider rear jaw is to allow a plurality of different attachment pin spacings, as occurs between different brands of accessory, to he accommodated by the coupler. Compare Figure 2 with Figures 4 and 7, In this embodiment, the rearjaw also has a radiused upper wall, which radius has a radial centre aligned with the axis of rotation 68 of the rear latch 64, Tn this embodiment, the rear latch 64 is a pivotal hook, with an elongated tip, and with an upturned nose at the end of the tip. This hook is designed to fit with a wide range of pin diameters, and with the radiused upper wall, it also so fits with a wide range of pin spacings.

Other embodiments may instead have a sliding latch. For those couplers, the radiused upper wall 70 is of less consequence, and thus it may instead be straight or fiat, The coupler may also have a lifting eye 72 as shown. In the preferred embodiment, this lifting eye is east onto the frame as an integral component thereof so as not to have a weld line a.s a line of weakness. By being cast, it is easily located on. the frame such that it is centred along the central vertical plane of the coupler, at the rear of the coupler, so as to allow lifts using the lifting eye 72 to impart a minimal sideways bending moment on the coupler and excavator arm.

The flame, instead of being cast, may instead be fabricated fiom plate steel, However, if fabricated, it is more likely that the lifting eye will instead he part of a side wall of the coupler so that again it can he integral to a part of the frame. This is an easier arrangement to fabricate, whej-eas with casting it can be readily mounted in the central vertical plane In addition to the rear latch 64, a front latch 74 is provided. The front latch or ABS TM also mounted for rotation about a pivotal axis 76 and its rotation is controlled by a hydraulic cylinder 73. The rotation of the rear latch 64 is instead controlled by a check valve operated hydraulic cylinder 80, the cheek valve 79 in this embodiment being screwed into a hole 81 in an end of a head manifold 83 of that cylinder 78, See Figures 1, 3 and 8. That check valve operated hydraulic cylinder 80 provides the main bias for the rear latch 64 to maintain it against the second attachment pin 62, as shown in Figure 2. The pressurised engagement of that rear latch 64 against that second attachment pin 62 retains the accessory in a firmly locked condition on the coupler 32, which is important to ensure there is minimal raffle of the accessory 34 rclativc to the coupler 32, since any such rattle will cause wear on the lear latch 64, and the two jaws 54, 56, which wear can ultimately cause an improper mounting of the accessory 34011 the coupler 32.

The check valve prevents the pressure loss, whereby the rear aw remains clamped shut by the rear latch even if there is a failure in the hydraulic supply lines.

The check valve operated hydraulic cylinder 80 is shown to he mounted at one end to a pivot axle 84 that is connected to the flame 48 of the coupler 32. This pivot axle 84, together with the pivot axis 76 for the front latch and the pivot pin forming the axis of the rotation 6. for the rear latch 64 together define three pivot axes for components within thc couplcr 34 that are mounted directly on the frame 48 of the coupler 32.

The other end of the check valve operated hydraulic cylinder 80 is connected to the rear latch 64 at a fiirthcr pivot 86. For that purpose, a pivot pin (not shown) would be inserted through the rear latch 64 to connect to a hub on the end of the piston rod 88 of the check valve operated hydraulic cylinder 80, thus allowing extension and retraction of that piston rod 88 to pushlpull the rear latch 64 between a position of engagement against the second attachment pin 62 (or a position of advancement in the event of a pin not being present in the jaw), as shown in Figure 2, and the position of non latching wherein the rear latch 64 is retracted away from the second attachment pin 62, or filly out of the rear jaw 56, as shown in Figures 4 and 6, respectively. As this occurs, the cylinder 80 may rotate about its pivot axle 84 relative to the frame and about the further pivot 86 relative to the rear latch. For a sliding latch, however, there may not be such pivoting, depending upon the geometry of' the chosen arrangement.

As for the front latch 74, and its hydraulic cylinder, it has a cylinder body and a piston rod 96. Ju this embodiment, the cylinder body is mounted at it s first end to the front latch 74 on a flange 90 that is ananged to extend away from the front latch's hinge axis approximately 700 from the plane of the leading surface 92 of the front latch 74. See Figure 5. DifFerent angles arc usable as well relative to the pivot axis 76 of the front latch 74 hut by mounting it at an angle such as 7Q0 (or greater), the locus of the cylinder pivot pin 94 becomes located above the pivot axis 76 so as to ensure that upon extending the cylinder 78 and its piston rod 96, as sjiown in Fignrc 6, the front latch 74 call be caused automatically to open the front jaw 54, rather than jamming that front latch 74 in a locked and latched condition (the latter resulting from an ovcreentrc arrangement -a non-desired arrangement).

From the other end of the cylinder body, the piston rod 96 extends and that piston rod has a free end which is mounted to a thrther component, again with a pivotal connection 98. That additional component is a blocking member 1 00 for the rear latch 64. The blocking member 100, as shown in Figure 4, is adapted upon retraction of the piston rod 96 olthe hydraulic cylinder 78 to be in a dropped or blocking position relative to the rear latch 64. lii thus blocking position, the rear latch 64 vill be prevented from frilly retracting away from the second attacluneni pin 62, even if driven by the check valve operated hydraulic cylinder 80 since a nib 102 on the rear o.1 the rear latch 64 will engage a free end 104 of the blocking bar or blocking member 100.

The blocking member 100, in this embodiment, is also mounted on. the same pivot axle 84 as the check valve operated hydraulic cylinder 80. This reduces the component count for the coupler and allows just the three frame mounted pivot axles 68, 84, 76 to he used for pivotally mounting four separate key components of the coupler.

In addition to that, three additional pivot axles are provided -86, 98 and 94. These, however, are free to move relative to the frame 48 by being instead located on the movable components within the coupler 32.

A final component of this coupler 32 is a secondary blocking member, and it could take the fonn of a drop finger as disclosed in GB1220135.6, the whole contents of which are inooqorated herein by way of reference. However, in this embodiment, a locking hook member 110 similar to that disclosed in GB2482515 is instead provided. The whole contents of that other case is also incorporated herein by way of reference. This locking hook member 110 is mounted about a pivot 112 via a slot in this embodiment such. that the hook has a variable length. This facilitates hooking and unhooking of a pin 113 on the frame by the hooked end thereof.

The pivot 112 is provided on a part of the blocking member 100, and thus moves with the blocking member, whereas the pin 113, being on the frame, is fixed.

The locking hook member 110 is gravity operated for preventing movement of the blocking member 100 when it can engage the pin 113, as shown in Figure 5, hut will allow lifting of the blocking member 1 00 when it misses that pin 113 see Figure 6. To miss the pin 113, the coupler is inverted to a crowd position (tinder the arm of the excavator). Gravity thus holds the locking hook member 110 vertical, and thus the hook will miss the pin when the blocking bar is lifted by the first actuator 78, However, if inverted not to a crowd position, i.e. in the wrong direction of curl, the hook will fall against the pin as that rotation occurs, thus preventing it from missing the pin if the blocking bar is attcinpted to be lifted by the first actuator, For example, therefore, fi'orn condition shown in Figure 2, if the coupler was to be rotated clockwise about the front attachment hole 114 in the top half of the coupler, i.e. the hole usually used for aftachment of the coupler 32 to the dipper arm 28 of the excavator 20, as opposed to hoJe 115 for the linkage arrangement 38, that rotation being such as to lift the lifting eye 72 of the coupler 32 (and this direction of rotation being the conventional direction for not achieving a crowd position, i.e. it is a uncurl ing direction), the locking hook member 110, by being gravity operated, would try to maintain a generally fixed vertical orientation, but would inevitable hiL the pin 113, as shown, and thus it would be able to hook onto the pin, thus preventing the blocking member 100 from being liftable. As such, rotations of the coupler in that direction would cause the coupler not to be releasable -the blocking member 100 would be retained in a dropped position, as sl1own in Figure 2, whereby the rear latch 64 cannot be opened. This offers an added degree of safety since such rotations would be in a direction to allow (lie front pin 60 to fall out of the front jaw However, to rotate the coupler about the front attachment hole 114 in the anti clockwise direction, i.e. to lower the lifting eye 72 would instead t.esult in the locking hook member moving away from the pin 1 1 3, as 1 0 shown in Figure 7 whereupon the first actuator, cylinder 78, can he used to lift the blocking member, as shown in Figure 6. In this direction of rotation the front jaw would be pointing upwardly, whereby the front pin would not be able to automatically fall out of the front jaw in the event of the rear jaw being opened.

The front latch 74, as previously described, is adapted for rotation about a pivot axis 76.

This rotation is between a latching position, as shown in Figure 2, and a non latching position, as shown in Figure 6. In the latching position, the front latch 74 has its leading surface 92 extending partway across the opening of the front jaw 54, Here it descends across that opening by about a half of the width of that opening. The front latch may he arranged to extend frirther across the front jaw, e.g. by changing its orientation, or by extending its length. llowever, the orientation is provided at an angle to the opening to ensure a click-on engagement of the front pin is possible, and likewise the length is chosen so as to minimise the overhang of the fron.t of the coupler -the overhang moves the accessory relative to the dipper ann, and any such movement needs to be minirnised, or else the accessory's atl.achment pin locations may need to he altered to compensate -digging force and digging capability depends upon the correct geometry of the relative moving and powering components.

When the front latch 74 is instead moved into the non. latching position, as shown in Figure 6, the leading surface 92 of the front latch 74 is lifted up into the ceiling of the front jaw 54, and in this embodiment it is flush therewith. Moving it out of the way of the attachment pin would be sufficient, however.

The degree of rotation of the front latch 74 between it s latching and non latching positions is iii this embodiment controlled by rotation limits, Here the angle of rotation is about i 8°, although angles of between 15° and 45° are ire1crred.

During use of the coupler, in a fully attached condition, as shown in Figure 2, the first and second attachment pins 60, 62 arc engaged ill their respective jaws 54, 56 with the first attachment pin 60 being seated in the base of the front jaw 54, and with the second attachment 62 being engaged by the rear latch 64 -in a clamped condition. The front latch does not perform a positive latching function (i.e. a clamping function), hut is instead purely a secondary latch in the sense that it i there to catch the flout attachment pin 60 in the event that the securement by the rear latch fails.

Then, to release the accessory, a first stage of detachment is to lift the blocking member 100. This is done by powering the cylinder 7. so as to extend the piston rod 96 and thus lift the blocking member 100 as shown in Figure 3. For this to occur, however, the coupler, when fitted with the locking hook member 110, or a drop finger, needs to have that element oriented relative to the blocking member so as not resist such a lifting. As already mentioned, this can be achieved by locating the accessory and coupler into the crowd position (curled un.dei. the arm, towards the cab of the excavator).

Once in that crowd position, the cylinder 78 can he operated to open the front latch 74 and lift the blocking member 100, hut in the embodiment shown, and in accordance with the present invention, an actuator arrangement is provided to achieve this in an advantageous manner the control of both hydraulic rams 78, 80 maybe controlled by a single control system 42. This will he described below with reference to Figures 8 to 18.

As shown in Figure 8, a first part of the actuator arrangement is the hydraulic cylinder for the rear latch 64. It has the piston rod 88, plus the head manifold 83 with the check valve 79 therein. Hydraulic fluid for extending the ram 80 comes through a first connection pipe 117 and the cheek valve 79 prevents any retraction thereof To retract it, however, pressurised fluid is provided to the other of the connection pipes 119 and to a rear connection pipe 121, thus releasing the check valve for retraction of the cylinder, as is conventional. These connection pipes are rigid, as is also conventional. However, a hydraulic manifold 123 is provided between those connection pipes 117, 119 121 to allow control thereby of the hydraulic fluid supply and return pipe, and a check valve 125, for the other ram 78.

This hydraulic manifold comprises three ports for removable hydraulic pipes, and a hole for a further check valve 125 (see Figure 9) for the front latch's rain 78. The manifold is a single block mounted on the main rain 80, hut it could be separate therefrom, or it might be in multiple components, some or and some off that ram, or all off that ram, e.g. on the frame of the coupler. The connection pipes might then beneficially he flexible between the manifold parts an.d the ram 78, e.g. where relative motion will occur.

The three ports arc respectively for a pair of hydraulic fluid supply and return pipes 127, 129 from the excavator's hydraulic control system (holes 131 and 137) plus a third pipe being the third laich's actuator's hydraulic fluid supply or return pipe 135 (see Figures 1 and 8). Only a single pipe goes to that first actuator 78, providing either a fluid supply (for expanding the rain 78) or a return path for fluid (when the mini 78 is contracting, e.g. due to a spring or gravitational bias). l'hat pipe connects to a left-most hole 137 when viewed as in Figure 12. However, in Figures ito 7, that left-most hole is moved elsewhere in the hydraulic manifold 123 -to the non visible right side 139 of that manifoid, The hydraulic jnanifold 123 then additionally has the three connecting pipes 117, 119, 121 extending therefrom, for the puiposes described above.

The hydraulic manifold then additionally has some connecting pathways between these ports and holes and pipes, as follows: a) A connection between the hole 141 for the cheek valve's inner end and the hole 137 for the pipe to the front latch's actuator 78, This, as shown in cross section in Figure 18, can be a short length 143.

I) A connection between a first of the holes 131 for the pair of hydraulic fluid supply and return pipes 127, 1 29 **. the one for retracting the main ram 80 -to the second connection pipe 119 and the rear connection pipe 121. This, a.s shown in cross section in Figure 13 can be by a long drilling tinough the block of the rnanifrdd 123.

c) A further conncction from that of connection b) above into the distal end or the hole for the check valve. This is to allow fluid communication within this connection through the check valve between the pipe to the front latch's actuator 78 and the first of the holes 131 when the check valve is open. As shown in Figure 13, this can be a cross drilling-shown by the circle 145 in Figure 13 and the tube Jength 145 (same feature) in Figure 15.

d) A connection from the second of the holes 133 for the pair of hydraulic fluid supply and return pipes 127, 129 -the one for extending the main rain 80 to the first connecting pipe 117, This connection 147 can he a thin bore as shown in Figure 14, as that provides a restriction to the.11 uid flow through that passageway. This has a usc as described below since it ensures the check valve for the other ram 78 can he opened and closed at required conditions.

e) A connection from that second hole 133 to the first latch's actuator's check valve's control port for opening and closing the check valve. Thus when that second hole is fed pressurised hydraulic fluid; the check valve 135 will open, thus allowing the small ram 78 to release to a non expanded state thus closing the front latch and dropping the hlocldng bar prior to the main ram 80 being extended -due to the restricted flow in connection d) above, the check valve 135 is opened immediately upon the main ram 80 being powered to extend it -the restriction causes a build up in the hydraulic manifold before the pressure builds hi the main ram 80. This connection e) is shown by the cross drill hole 149 shown in Figure 14 and the upper pathway 149 (same feature) in Figure 15. It crosses above, not through, the crossing pipe 151 within the manifold 123 that extends between the holes for the two main ram 80 retraction feed pipes 119 and 121.

This connection may also have a reduced diameter compared to the other pipes, but a larger one than that of connection d. The sized ensure the pressure buildups occur in the colTect order for the check valve 135 correctly to operate.

Tn a single block anangemerit, these pathways can be created by appropriate drillings, as illustrated in the drawings, and will become operational once the relevant ends are either plugged or connected to the relevant pipes or check valve. Alternatively hcy can be provided by appropriate pipes between the relevant components of' the hydraulic manifold (Le. if not in a single block).

the blocking member and the II'cmt latch 74 may lift in either order, or together, but are preferably arranged such that the ram 78 lifts the blocking member first, since its lever arm relative to its axis of rotation and centre of gravity provides a rotation moment that is more favourable than a rotation moment created by the lever arm of the front latch relative to its axis of rotation and centre of gravity, l-Iowcvcr, the geometiy can he altered, or spring biases added/changed, to change that order, or to make them operate siinultaneou sly.

Only onee both are open, or potentially j usL once the blocking member is lifted, the rear latch 64 can also be powered into its retracted (open) condition by activation of the other ram 80. Thus, the "two-jaws-fullyopcn" condition of Figure 6 is arrived at, whereat the two attachment pins 60, 62 can be disengaged floni the coupler, or new ones can he inserted this condition is the preferred starting point of an attachment process). A "click-on" of a fi'ont pin into a closed front jaw, however, is typically possible, so this frilly open condition is not essential for an initiation of an attachment process.

Once a first affachnient pin 60 has been engaged into the front jaw 54, the coupler can be rotated to move the second attachment pin 62 into the rear jaw 56. At that point, the hydraulic eyliiders can he powered to extend the main ram 80 to move the rear latch hack into a latclung position, and at the same time the other acluatci' 78 will contract for moving the front latch and the blocking bar 100 into their default latched/blocking positions, as shown in Figure 2.

A spring bias is preferably provided within the front latch's hydraulic cylinder 78 to default the cylinder towards a contracted condition so as to draw the front latch into its latching position and the blocking member into its blocking position. Fui'ther, this ram may have a leaky valve to its hydraulics, thus allowing the hydraulic pressure to expand or contract the tam to overcome the spl.'ing, hut to allow the spring to contract the rain in the event that that the hydraulic pressure drops below a threshold. Thus, powercd operations can cause the rain to overcome the spring bias, but the spring bias overeoiiics the hydraulic pressure in the event that the hydraulic pressure is lowered below that threshold. It is preferred, however, that the actuator aiTangement is as shown in Figures 8to18.

In one arrangement, the front latch's ram. 78 is a displacement ram' with an internal spring -typically one with a high resilience, so as to bias the ram towards a retracted slate, Tins will thus hold the front latch and the blocking member in their 1 0 blocking/latching states. Further, the ram preferably has only a single hydraulic feed line. The component count is thus low, When the ram is activated, the feed line fills the ram with oil, thus extending the rod to release or lift the latch/blocking member -the pressure overcomes the spring bias.

Such a displacement ram is beneficial since it allows for misuse of the coupler. For example, consider the situation where the front latch and the blocking memler are both down (i.e. in th.e blocking/latching positions), hut with no accessory 34, such as a bucket, attached, and with the oilier ram extended to put the rear latch into its own advanced or latching position (normal practice on site, e.g. for lifting operations using the lifting eye, to eliminate any warning buzzer in the cab that might otherwise he sounded). If the operator was to pick up an attachment on the front jaw, the lack or insufficiency of pressure from the single feed line, or the spring, would barely resist this action, thereby allowing the front latch to open to receive the pin, with the small spring loaded ram cycling to an extended state as the fl-out latch opens. This would thus allow such an operation to occur without breaking the coupler's internal components (such as the latches or rams or hoses or manifolds). Further, due to die spring, the front latch would also automatically close when the pin was in the coupler's front jaw -the front latch thus also snaps shut. This is the click-on fi.mction, and secures the pin from slipping out of thejaw The non-blocked and spring biased front latch therefore offers two very good advantages: 1. It prevents pick and place being carried out unsafely -accessories such as buckets cannot be partially engaged in the front jaw (in which circumstance they risk skidding off thc flout jaw if manoeuvred by that front jaw, i.e. in circumstances where they are picked up by the front pin only. Instead they will fully click into the jaw in an engaged state. 2. The hunt latch mechanism is effectively damage proof during engagement procedures since it will open if forced.

A flarther redundant, but useftul precautionary feature is on the rear latch -that latch is shown to he a hook with an extended tip and an up-turned nose. This is also a beneficial hut non-essential feature, and as such it is often missing from prior art couplers. It is to prevent a force on the hook from releasing the pin, e.g if the rear latch's ram 80 fails.

The upturned nose prevents a rotation of the hook into a release condition even if the ram br the hook has failed or burst since the pin, which will be supported on the hook clue to gravity, and as it engages that nose, any further rotation of the hook towards a release position will be resisted, thus tending to move the latch back towards a latching position.

As briefly mentioned above, the frames of the couplers will typically be cast, and this is preferred to he dine substantially in a single piece, although hardened steel inserts might he added/welded therein post casting, e.g. for the jaws and pin/pivot mounts.

Alternatively the flames can he fahmleated from plate steel using known cutting and welding techniques, as is conventional for many prior art designs.

The other components such as the latches and the blocking member(s) can also be east, although they nay instead he fabricated from plate steel using known cutting and welding techniques.

The present invention thererore provides an easily activatable, and an easily releasable, coupler that still offers the secured attachment of the prior art -with the numerous (more than one) redundant safety features, such as the blocking member for the rear latch, the front latch, the profiled nose on the rear jaw and the blocking member for the blocking member.

ft shou!d be appreciated that the invention has bccn described above purely by way of example. 1-Jowever, modificatioiis in detail may be made to the invention as lhiiited purely by the claims appended hereto.

S

Claims (26)

1. CLAIMS1. A coupler for attaching an accessory to an excavator arm of all excavator, the coupler comprising a first jaw with a movable first latch, a second latch having a retracted position and at least one advanced position, and a blocking member for selective interaction with the second latch via a movement between a non-blocking position and at least one blocking position, such selective interaction being such as to resist movement of the second latch from the appropriate at least one advanced position into the retracted position when tile blocking member is in the appropriate at least one hlocking position, the coupler further comprising an actuator arrangement comprising two linked hydraulic actuators for connection to a pair of hydraulic fluid fccd or return lines, a first of the actuators being for selectively moving both the blocking rnemhei and the first latch and a second of the actuators being for selectively moving the second latch, wherein the link between the two hydraulic actuators is a hydraulic link such that activation of hydraulic pressure in the actuator arrangement in a manner intended for causing a retraction of the second actuator, for retracting the second latch towards tile second latch's retracted position, also causes an actuation of the first actuator to extend that first actuator so as to move at least the first latch into its non-latching position.
2. 2. The coupler of claim 1, wherein that activation of hydraulic pressure also moves the blocking member into non-blocking position.
3. 3. The coupler of claim 1 or claim 2, wherein the blocking member and the first latch are arranged to be moved together.
4. 4. The coupler of claim 1 or claim 2, wherein the blocking member and the first latch are arranged to move in turn.
5. 5. The coupler of any preceding claim, wherein the fits! actuator is associated with a check valve such that the first latch will lock into a non-latching position when hydraulically moved thereto by that activation of hydraulic pressure.
6. 6. l'hc coupler of any preceding claim, whercin the check valve is mounted on a hydraulic manifold of the second activator.
7. 7, The coupler of claim 6, wherein the manifold has a port for connection of a third hydraulic fluid feed and return line for connecting the first actuator thereto.
8. 8. The coupler of any one of claims 5 to 7, wherein the check valve is hydraulically conncetcd to the actuator assembly such that activation of hydraulic pressure in the actuator arrangement in a manner intended for causing an extension of the second 1 0 actuator will release or hold open the check valve such that the first actuator is flee to retract.
9. 9. The coupler of any preceding claim, wherein the first actuator connects to only a single hydraulic fluid feed and return line.
10. 10. The coupler of any preceding claim, when dependent upon claim 6, wherein the manifold also has connection points for the pair of hydraulic fluid feed or return lines.
11. 11. The coupler of ciaim 1 0, the manifold also having a pair of hydraulic fluid connection pipes extending to a head manifold of the second actuator,
12. 12. The coupler of claim 10, wherein the head manifold comprises a check valve of the second actuator,
13. 13. The coupler of any preceding claim, wherein the hydraulic flow path to the second actuator for extending the second actuator has a greater resistance to fluid flow than the hydraulic connection thereto for the check-valve o.r the first actuator such that the check valve for the first actuator will open before the second actuator starts to extend.
14. 14, The coupler of claim 13, wherein the greater resistance is provided by a narrow fluid pathway in thc hydraulic manifold at the point that it connects to one of the connection pipcs, or by a restriction or narrow pipe elsewhere along that fluid pathway to the second actuator.
15. 15. The coupler of any preceding claim, wherein either or both of the blocking member and the first latch arc arranged to move prior to the movement of the second latch into its retracted position.
16. 1 6, The coupler of any one of the preceding claims, wherein the coupler comprises a third latch back-tip mechanism that can prevent inadvertent detachment upon a failure of 1 0 an element within the coupler, that latch back-up mechanism being the shape of one or both hitches,
17. 17. The coupler of claim 16, wherein the second latch is a hook with an upturned nose to resist an inadvertent release of an accessory pin from the hook in the event of a main actuator failure.
18. 18. The coupler of claim 17, wherein the hook is arranged to rotate about a pivot.
19. 19. The coupler of any one of the preceding claims, wherein the coupler comprises a latch back-up mechanism that can prevent inadvertent detachment upon a failure of an element within the coupler, that latch hack-up mechanism being a secondary blocking member arranged selectively to resist movements of the blocking member from a blocking position into a non-blocking position.
20. 20, The coupler of claim 19, wherein the secondary blocking member is a free-swinging hook, attached to the blocking bar, and adapted to selectively catch on a pin of the frame of the coupler.
21. 21. An actuator alTangelnent for an excavator coupler, the actuator aiTangement comprising two linked hydraulic actuators for connection to a pair of hydraulic fluid feed or return lines, a first of the actuators being for selectively moving both a blocking member an.d a fiTSt latch of the coupler and a second of the actuators being for selectively moving a second latch of the couplet, wherein the link between the two hydraulic actuators is a hydraulic link such that activation of hydraulic pressure in the actuator arrangement in a manner intended for causing a refraction of the secon.d actuator, for retracting the second latch towards a latch retracted position, also causes an actuation of the first actuator to extend that first actuator so as to move at least thc first latch into a non-latching position.
22. 22. A coupler comprising the actuator arrangement of claim 21.
23. 23. A coupler substantially as hereinbefore described with reference to any one of Figures Ito 18.
24. 24. An excavator comprising a coupler according to any one of claims I to 20, 22 or 23.
25. 25. A method of using the excavator of claim 24, comprising powering the actuator arrangement for extending the second actuator, whereupon the fl.tnt iatch adopts a latching state and the blocking bar drops to a blocking state.
26. 26. A method of using the excavator of claim 25, compr sing po'cvering the actuator anangemeit for retracting the second actuator, whereupon the front latch adopts a non-latching state and the hloekin.g bar lifts to a non-blocking state.