WO2010061165A1

WO2010061165A1 - Coupler with coupling status sensors

Info

Publication number: WO2010061165A1
Application number: PCT/GB2009/002602
Authority: WO
Inventors: Gary Miller; Ronald Keith Miller; Doreen Jacqueline Miller
Original assignee: Miller International Limited
Priority date: 2008-11-03
Filing date: 2009-11-03
Publication date: 2010-06-03
Also published as: CN102224303A; GB2464988A; EP2350396A1; GB2464988B; GB0820116D0; GB2464988B8; CN102224303B; US20110313625A1

Abstract

A coupler (24) for coupling an accessory (28) to an excavator arm (12) of an excavator (10), the coupler comprising a first jaw (30) that points in a generally longitudinal direction relative to the frame of the coupler (24), the jaw (30) being for receiving a first attachment pin of an accessory (28) and having a first sensor (40) for detecting the presence of an attachment pin therein, the coupler (24) further having a second jaw (32), or a latch (34), longitudinally spaced from the first jaw (30), and being for receiving a second attachment pin of the accessory (28), and having a second sensor (42) for detecting the presence of an attachment pin therein. The sensors (40, 42) transmit or send signals to a receiver (46, 48) for notifying the driver of the coupling status of the coupler (24) with respect to the accessory (28).

Description

COUPLER WITH COUPLING STATUS SENSORS

The present invention relates to a coupler for remotely attaching accessories, such as buckets, to an excavator arm of an excavator, e.g. from the cab of the excavator, the coupler being provided with coupling status sensors.

Couplers for remotely attaching accessories to an excavator arm of an excavator are well known per se. However, few such couplers have sensors built into them. Nevertheless, such couplers, with sensors, are known, and one such coupler is disclosed in EP 1318242, to Geith Patents Limited. That document discloses a coupler with a sensor for detecting when the coupler has been moved into a crowd position (i.e. a fully curled position), and control electronics for permitting the coupler to commence a decoupling procedure only while the coupler is in that crowd position. That crowd position is deemed to be a safe position for decoupling procedures since in that crowd position, the coupler is arranged such that its front jaw is pointing at least partially upwards, whereby an accessory to be attached, or detached, which coupler will already have an attachment pin located within that front jaw, cannot fall off the coupler even if all other retaining mechanisms for that accessory are released.

Another prior art coupling system is disclosed in US2004/0244575. It likewise looks for the occurrence of the crowd position. However, it does so by monitoring for a full extension of one of the excavator arm's hydraulic rams, i.e. the ram that causes the crowd position to occur.

Despite the prior art teachings, however, there is still a possibility that a user will misuse couplers by using them, for example, for transporting accessories without a proper coupling of the accessory onto the coupler, e.g. by just hooking an attachment pin of an accessory onto that front jaw without completing the coupling procedure (i.e. by engaging/locking the second attachment pin of the accessory into the rear jaw of the coupler). Such improper uses can give rise to dangerous situations since the attachment can often be shaken out of that front jaw, or it can be accidentally released from that front jaw if the arm and coupler are uncurled. This danger is particularly prevalent given that it is not always immediately apparent whether the accessory is properly attached to the coupler, e.g. upon a user returning to the excavator after a lunch break, and since the accessories are often extremely heavy and large, especially in the mining industries, whereby an accidental decoupling can present a serious risk of serious injury to the user and bystanders alike.

The present invention, therefore, seeks to provide a mechanism for preventing or dissuading a user from engaging in such improper uses of couplers.

According to the present there is provided a coupler comprising a first jaw that points in a generally longitudinal direction relative to the frame of the coupler, the jaw being for receiving a first attachment pin of an accessory, wherein a sensor is provided for that jaw for detecting the presence of an attachment pin therein.

The sensor may be adapted to output a signal to signify the presence of an attachment pin in the jaw. Alternatively, or in addition, the sensor may be adapted to output a signal to signify no detected presence of an attachment pin in the jaw.

The sensor's signal may be transmitted or sent to a receiving unit, or to a transmitter, for allowing an indication of the sensed information to be passed to a user. The transmission may be along a wire, or it may be wireless, for example a radio transmission. Such wireless transmitting technologies are well known in the automobile arts. See, for example, keyless entry systems, tire pressure monitoring systems, and Bluetooth® systems for linking mobile telephones to the vehicle's audio system.

The user to whom the sensed information is passed, preferably sees, hears or feels the indication while he is within a cab of the excavator to which the coupler is attached. That receiving unit, or a display/indicator mechanism therefor, may therefore be integrated into the excavator's dashboard. In another arrangement, the receiving unit, or a display/indicator mechanism therefor, may be provided as one or more separate components for fitting onto or into the excavator, again preferably within the cab of the excavator. The user, while in the cab, can thus be notified whether an attachment pin is positioned in that first jaw. The sensor may be a strain sensor. This could detect the presence of an attachment pin within the jaw since accessories, and excavator arms, are generally very heavy. Therefore, even if the accessory is resting on the ground, the weight of the accessory, or the weight of the arm, will usually cause a force to be applied to the jaw by the accessory's attachment pin. That force will stress the jaw, thereby creating a detectable strain, perhaps in the throat of the jaw. Therefore, a strain gauge located at or in the jaw would be able to detect the presence of an attachment pin within that jaw.

Other possible sensors might be contact sensors, e.g. PTM (push-to-make) switches. Yet further possible sensors might be magnetic sensors - the attachment pin is usually made of steel. The skilled person will appreciate, however, that numerous different sensors, or combinations thereof, could be used for detecting the presence, or not, of an attachment pin within the jaw. The advantage of a strain sensor, however, is that it will detect the presence of the attachment pin irrespective of where the pin bears against the jaw, since the stain will be distributed around the throat of the j aw.

The coupler may also comprise a second jaw, longitudinally spaced from the first jaw with respect to the frame of the coupler. That second jaw is preferably facing substantially downwards, i.e. approximately perpendicularly to the first jaw, and away from the end of the arm of the excavator that is attached to the coupler. The second jaw is for receiving a second attachment pin of the accessory, and it is preferably associated with a pivoting or sliding latch for locking that second attachment pin within that second jaw. In some known couplers, however, just the pivoting or sliding latch is provided — the jaw is omitted.

Preferably a sensor is associated with that second jaw, or the pivoting or sliding latch. That second sensor can be instead of the first sensor, or in addition to the first sensor.

The second sensor is preferably also for detecting the presence of, or the absence of, an attachment pin. However, that detection is for the second jaw, or for the pivoting or sliding latch, instead of the first jaw. Preferably the second sensor is mounted directly onto or into to the pivoting or sliding latch, or onto or into that second jaw's alternative locking mechanism. Locating it into or onto a pivoting or sliding latch, however, is most preferred since most commercial couplers feature either a pivoting hook or a sliding plate for providing such a locking function.

Preferably the second sensor is a strain gauge. However, any suitable sensor could be provided, as for the first sensor.

The second sensor may have similar or identical features to the first sensor. However, upon transmitting the signals to the receiving unit, the source of the signals, i.e. with respect to which sensor they came from, is preferably discernable by the receiving unit. For transmissions made wirelessly, this can easily be achieved by using ID codes in the transmitted signals, or even by using a single transmitter for transmitting both sensors' signals in receiver-recognisable manner. Such coding technologies are well known in radio transmitting arts, such as tyre pressure monitors.

It should also be observed that sensors and transmitters can readily be made suitably tough to cope with the environments to which couplers are exposed by using designs developed for tyre pressure monitors. After all, such prior art systems are designed to cope with high speed tyre environments, and the associated forces encountered therein. Therefore, a further discussion of the specific design of suitable sensors and transmitters is not required herein.

The indicator unit for indicating the sensed information to the user is preferably in the cab of the excavator. It preferably has visual indicators. They preferably separately provide an indication of the coupling status of the first and second jaws, i.e. whether there is an attachment pin in the respective jaw. In a simple embodiment, that may be by means of a light for each jaw. For example, the light for a jaw could be illuminated when an attachment pin is located within the relevant jaw, or perhaps when an attachment pin is not located within the relevant jaw. The user can therefore instantly determine the accessory engagement status of the coupler. In a preferred embodiment, a green light signifies safety and a red light signifies danger. Therefore, when both jaws are correctly engaged against a pin, i.e. the front jaw's sensor senses the presence of a pin, and the rear latch's sensor also senses the presence of a pin, two green lights can show on the indicator unit. This indicates a safe mounting of an accessory on the coupler. However, if only one pin is sensed, a red light could be illuminated. That would indicate an unsafe mounting condition.

An alternative arrangement would have a green light show when the first jaw is correctly engaging a pin, but with a red light showing for the second jaw until that second jaw is correctly engaged with the second pin.

It is possible also to illuminate green lights when no pin is sensed, since the coupler would then not be attached to an accessory, whereby it is safe - there is no risk of an accessory falling off of the coupler. This is useful since couplers typically also feature a lifting eye, which can be used for lifting items with chains or ropes.

A third sensor, and a third light, might also be incorporated into the coupler at the hydraulic ram. It can sense the location of the latch mechanisms by determination of the state of the ram. That status information can also be transmitted to the receiver for analysis and evaluation. Likewise, a sensor could be provided for sensing the orientation of the coupler.

These and other sensors may be used together with other sensors to build a virtual picture of the condition of the coupler for analysis by a control system, which control system can provide suitable warnings to the user if dangerous conditions are encountered, or simply feedback to the user to assist with coupling or decoupling procedures since those procedures usually require a number of steps to be undertaken, and the control system could signal to the user when a particular step has been completed, e.g. retraction/advancement of the ram, or inversion of the coupler. See WO2008/029112 or GB0808113.5 for disclosures of various coupling and decoupling procedures. The sensing systems, or the receiver, can be linked to the hydraulic control system of the excavator. With such an arrangement, if an unsafe condition is sensed, the hydraulic system's output can be restricted. For example, the detection of just one attachment pin, e.g. in the first (front) jaw, could cause not just the illumination of a red light on the display unit for the second jaw's sensor, but also a restriction in the operability of the excavator arm. For example, lifting or swinging motions might be restricted, prevented or slowed. One such restriction might be the provision of a half throttle setting for the hydraulics, or rotation limits for swinging elements. These restrictions could prevent unsafe digging activities from being carried out, but without preventing dangerous situations from being recoverable using the hydraulics. A user would thus be prevented or discouraged for undertaking unsafe working practices with the excavator and coupler.

In addition to controlling or limiting the hydraulics usability, the excavator's manoeuvrability or engine power might also be linked to the sensing system, or to the receiver, whereby they might also be restricted if a dangerous or unsafe accessory condition is sensed. This could be useful since it could additionally prevent movements of the excavator around a worksite while an accessory is incorrectly mounted onto the coupler. That would further prevent or discourage improper operator practices, thereby further reducing the possibility for a user to expose himself, or others, to dangerous situations of his own making.

In one embodiment, an additional or separate sensor forms part of a work-tool recognition system. The work-tools for such a system are additionally provided with a readable or transmittable indicator. That indicator might be optically, magnetically, inductively or capacitively readable, or it might be a transmitted signal that can be received and read by the coupler's sensor. Such transmissions can be via wires or they can be wireless.

In preferred embodiments, the indicator is either a barcode (and the sensor on the coupler is a barcode reader) or an RF (radio-frequency) transmitted signal, which signal might be emitted in response to an interrogation by a sensor on the coupler, or in response to a circuit being completed by the coupling process. Such RF signals would preferably be in the form of a transmitted ID code, or in the form of a more informative signal containing an ID code and some other usable information.

The other usable information is preferably indicative or one or more of the following parameters: tool type (i.e. bucket, grabber or drill), tool weight or tool capacity (to allow the operator, or the excavator itself, to know/decide whether the excavator is man enough to handle to tool), tool serial number (to allow the specific tool to be tracked), tool age or duty cycle (to allow the operator, or the excavator itself, to know/decide whether the tool is still safe to use, or whether it is likely to suffer a fatigue failure), and tool configuration (e.g. attachment pin size or attachment pin spacing, to allow the coupler to know whether the tool is mountable onto the coupler).

Likewise, a sensor might be provided on the coupler to read information from the excavator or the excavator arm. For that purpose, the excavator and/or the excavator arm can be additionally provided with a readable indicator. Similar readable indicators as those that are disclosed above for the accessory could be suitable also for the excavator and/or the excavator arm.

Instead of mounting the additional sensors onto or into the coupler, the additional sensors might be mounted onto the accessory, or onto the excavator arm/excavator, with the coupler then having the readable/transmittable indicator(s).

With these additional sensors and indicators, couplers, excavators and accessories can be recognised, and thus known limitations of the accessories, couplers or excavators can be accommodated by the control electronics of the excavator. For example, if an accessory such as a drill is attached, the excavator might want to be limited as to how much lateral force gets applied to the accessory during drilling operations. With such a tool recognition system, such limitations can be imposed automatically by the excavator's control electronics, thereby reducing the likelihood of, or preventing, operator error causing severe damage to accessories. Preferably the sensed information is sent to the excavator's receiver for processing by the excavator's OEM ECU. That ECU preferably has a memory for storing use information for particular tools or accessories.

Likewise, preferably an ECU is located in the coupler, also with a memory, whereby information as to which accessories and which excavators have been attached to the coupler can be stored, or even to allow the coupler to have its own intelligence for enabling it to refuse to couple to accessories that fall outside the achievable capacities of that coupler, i.e. accessories that are too heavy.

Additional sensors might also be provided in the coupler to sense the loading applied to the coupler during use of an accessory. Those sensors could be the above-mentioned strain gauges. These could be used to sense overload conditions in the coupler during such use. Those overload conditions might be overloading of the coupler, e.g. the jaws or the latching hook, or of the lifting eye, or they might be overloading of the accessory, e.g. where the coupler has recognised the accessory to have a maximum loading capacity, or a maximum digging/drilling force capacity. The coupler could then emit a warning to the operator to inform the operator of that overload condition, or it may signal that condition instead to the excavator's receiver/ECU, whereby the excavator can impose operational restrictions automatically.

Sensors might also be provided in the coupler, or in the accessory, or in the excavator, to provide coupler/accessory/excavator tracking capacity, e.g. by the use of GPS sensors, and memorising the identity and location of each accessory/excavator/coupler coupling combination. Then, that stored information might be used to locate specific products in the future, or for tracking the movement of specific products. This allows the movements of a company's fleet and assets to be tracked. Further it can assist in the tracking down of stolen accessories or couplers.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 schematically illustrates an excavator fitted with a coupler in accordance with the present invention; and

Figure 2 schematically illustrates details of that coupler.

Referring first to Figure 1, there is shown an excavator 10 comprising an excavator arm 12, a cab 14, an engine area 16, tracks 18 and hydraulic rams 20 for controlling the operation of the excavator arm 12.

A coupler 24 in accordance with the present invention is attached to the free end 22 of the excavator arm 12. For that purpose, two attachment points 26 (see Figure 2) are provided on the coupler 24, and two attachment pins (not shown) extend through those attachment points 26 for making the attachment. This type of attachment system is conventional in the art.

An accessory 28 is then attached to that coupler 24. As a result, the excavator 10, via its excavator arm 12 and hydraulic rams 20, can be used to perform operations with the accessory 28.

In this embodiment, the accessory 28 is a bucket, so normal operations will be digging.

Referring now to Figure 2, additional details of the coupler 24 will be described.

The two arm attachment points 26 are positioned in a top portion of the coupler 24. The bottom portion of the coupler 24 then has the accessory attachment components. They include a front jaw 30 and a rear jaw 32, each of which will engage attachment pins, but this time on the accessory 28. For that purpose, the front jaw 30 points substantially longitudinally relative to the main axis of the coupler 24 (i.e. towards the cab in Figure

1), whereas the rear jaw 32 points downwardly, i.e. towards the main body of the accessory. As such, the front or first jaw 30 can pick up the accessory by hooking onto a first attachment pin of the accessory, and the second attachment pin of the accessory can then be swung into the open mouth of the rear or second jaw 32. Then, via a pivoting latching hook 34, the rear jaw 32 can be closed for securing the second attachment pin as well. The accessory 28 is thus fully coupled onto the coupler 24.

The pivoting latching hook 34 is driven into its pin-engaging position by the coupler's own hydraulic ram 36, i.e. a hydraulic ram 36 that is contained within the coupler 24.

The above features of the coupler are also all conventional. They are also interchangeable with alternative mechanisms known in the art. For example, additional securement mechanisms can be incorporated into the coupler, such as in GB2330570 or WO2008/029112. Further, instead of a pivoting latching hook 34, a sliding latching plate might be preferred. Likewise, instead of the hydraulic ram 36, a screwthread drive, or merely a lever-releasable spring could be provided for moving the pivoting or sliding latch 34.

The rear of the coupler 24 is also provided with a lifting eye 38. This allows items to be safely hoisted using ropes or chains.

All of the above elements of the illustrated coupler are known or conventional in the art. Therefore, their respective uses and applications should not need to be discussed further. It should be appreciated, however, that these couplers can be provided in a wide range of sizes, i.e. in sized that are suitable for use with a range of excavators.

The inventive features of the present invention are the additional elements disclosed in the following passages:

The coupler is adapted to include sensing and communication technologies. They serve to provide information to the excavator driver in the cab via a display, although the information might be presented elsewhere if preferred. The presentation of the information, however, allows the status of the coupler, or of any coupling/decoupling procedure, i.e. "work tool attachment status" to be communicated to the driver. Likewise it can be reported to a control system in the excavator for providing automated interlocks, which once implemented can prevent certain undesirable or unsafe actions from being carried out by the operator until an appropriate verification of the coupler's condition or status is achieved by the system.

Manual overrides might be provided. However, it would be preferable if they could be avoided to ensure that no improper uses can occur.

The provision of such interlocks, or "limp modes", such as reduces throttles, or restricted movement ranges, or reduces hydraulic power, will greatly improve workplace safety by preventing or averting dangerous operations of the excavator, or by minimising or eliminating misuse opportunities.

The sensing and communication technologies, in the illustrated embodiment, comprise a selection of sensors, any one of which can provide a useful and advantageous function in its own right. The first sensor 40 is a sensor provided for the first jaw 30. It is for detecting whether an attachment pin is located within that front jaw 30. This could be a proximity sensor, a touch or push actuated sensor or a parameter measuring sensor — e.g. a stress or strain measurement or sensing device. It is shown, to be located at the throat of the front jaw 30. This is where an attachment pin will typically sit, whereby it will usually be the optimum position. However, it is possible that more than one sensor, in different positions on that jaw 30, will be necessary to ensure that any attachment pin within that jaw can be sensed. This would be of particular value in front jaws having dual-radiused throats (see, for example, Registered Community Design No. 000452271.0003). That is because a second sensor in the wall of the larger radiused portion of the jaw would allow a large diameter attachment pin, i.e. one which would not fit into the back of the throat of the j aw 30, also to be sensed.

The optional second, or further sensor 42 is provided for the second or rear jaw 32. In this embodiment it is located in the pivoting latching hook 34. This second sensor 42 can be identical to the first sensor, in that it is also for detecting the presence of an attachment pin in its associated jaw - the rear jaw 32. By positioning it in the hook, it will only detect the attachment pin upon the engagement of that attachment pin by the pivoting latching hook 34. This prevents a false detection of an unsecured attachment pin. However, if a separate sensor detects the location of the hook, that same level of detection could be achieved with the second sensor being located in the throat of the second jaw.

Again more than one sensor might be provided since different attachment pins might engage against different parts of the jaw, or against different parts of the hook, especially where the two attachment pins are from an accessory that has a different centre-to-centre pin spacing.

The coupler of this exemplary embodiment also has a third sensor 44, which sensor is located within or upon the hydraulic ram 36. It might likewise be located within the ram's hydraulic supply-line. This sensor serves to detect either or both hydraulic pressure or hydraulic ram extension status. Such data can serve to allow an even better picture of the coupler's status to be determined. For example, it allows the position of the pivoting latching hook 34 to be checked, or it can identify a hydraulic fluid leak.

Other sensors, not shown, can include orientation sensors, for determining whether the coupler has been inverted, or perhaps to what degree it has been inverted. These can be helpful in ensuring that a decoupling procedure is not commenced while the accessory 28 is in an unsafe position relative to the coupler 24, i.e. such that it could fall from the coupler if the rear jaw was opened.

Yet further sensors might be provided to identify information from the accessory themselves, for example from a transponder in the accessory, for detecting accessory type or accessory capacities, which information can also be of potential use to a central control unit. That information could be stored in the transponder within the accessory.

In the illustrated embodiment, the various sensor components are shown to be integrated into the components of the couplers. As such, the coupler is bespoke fabricated with the sensors built therein. It should be appreciated, however, that sensors will be incorporatable into existing couplers, or known coupler designs, by way of retrofits. Likewise, the associated control electronics, such as those that will be found in the coupler's central control unit 46 in Figure 2, can be either pre-built onto or into the coupler's frame as an integrated part of the coupler 24, or they might be an aftermarket addition.

In the illustrated embodiment, the first two sensors 40, 42 are adapted to sense the presence of an attachment pin in their respective jaw or hook, and the third sensor 44 serves to detect the hydraulic pressure within the hydraulic ram 36. That sensed data is then either intermittently or continuously sent to the associated control electronics for analysis, or for transmission to further control electronics such as a receiver 48 in the cab. The resulting status information about the coupler is then displayed to the user, or else (or in addition) the data is acted upon by the excavator's own control electronics in the appropriate manner, such as by allowing excavator operations, or by implementing appropriate "limp modes" for the detected coupler status. Numerous possible actions in that regard are possible. For example, the display could have lights signifying good or bad conditions for each sensor, such as a green light for a good sensed condition and red for a bad sensed condition, with the display showing all green lights when an accessory is fully coupled to the coupler, and at least one red light when an accessory is detected to be incorrectly coupled to the coupler. A limp mode for the excavator would be likely to be implemented whenever such a red light is indicated.

As indicated above, it will be appreciated that the jaws' sensors should be designed to detect a variety of different attachment pins, such as pins with different radiuses, or different centre-to-centre pin spacings. This is because an excavatore will frequently be used with a variety of different accessories, and not all necessarily from the¹ same manufacturer - such different accessories often have different pin spacings, or different pin radiuses. Further, attachment pins can become worn, whereby the pin spacing between the two pins of an accessory can vary over time.

It will also be appreciated that the sensors should be capable of handling, or at least be protected from, the various harsh environmental conditions that a coupler is likely to be exposed to, such as temperature extremes, regular exposures to abrasive materials such as stones, rocks and mud, rough handling, and also immersion in sea water, fresh water or mud. Such toughened sensor technologies are already available, such as from neighbouring fields like tyre pressure monitors. In one preferred embodiment, the pin sensors 40, 42 in the front and rear jaws 30, 32 are stress or strain sensing sensors. The can detect the presence of an attachment pin within a jaw since accessories are generally very heavy, whereby the jaws will be exposed to significant loading under the weight of an attached accessory. Such stress or strain sensors could therefor detect the presence of an attachment pin by the detection of such forces. Further, since those forces will be experienced around the jaw, rather than just at a specific location on the jaw (i.e. the contact location between the pin and the jaw), the location of the sensor is less significant in determining the ability of the sensor to achieve its function.

Instead of stress or stain sensors for the first and second sensors, however, proximity sensors might be provided. They could detect the proximity of an attachment pin within the jaws.

In the illustrated embodiment, the three illustrated sensors 40, 42, 44 are connected to the central control unit 46 either with wires or wirelessly - the sensors can be wired to the central control unit 46, or they can have their own radio transmitters built into them. That central control unit 46 therefore receives the sensed signals from those sensors and can compile that information ready for transmission to the receiver 48 in the cab 14 as intermittent databursts. That receiver 48 is shown to be within the cab of the excavator 10, but it could be elsewhere, with it instead being connected to a display.

The receiver therefore receives the transmissions through a wireless transmission such that the receiver can process the sensor data and cause the display or the excavator's control system to act appropriately. The present invention therefore allows the coupler to transmit its own coupler status information reliably to the driver in the cab of the excavator.

It will be appreciated that transmission and receiver technologies suitable for such transmissions are well developed in various arts, including tyre pressure monitors. Further, any necessary coding or pairing systems for such transmission/receiver pairs are well developed in those arts. A further discussion of them here is therefore not necessary.

In place of a wireless transmission to the cab, a wired system could be used to transfer the data. This has the advantage of no local power being needed at the coupler — the sensors could be powered by the excavator's own power system. However, wireless transmissions are preferred since they are easier to incorporate into existing excavators and couplers — they need minimal setting up, and can readily allow couplers to be removed from the excavator for servicing.

To power the wireless transmitters, preferably an onboard power system is provided on the coupler. That could simply be a battery within the central control unit 46. However, a generator might be alternatively be provided on the coupler for generating the required power through kinetic energy recovery - couplers experience a great deal of shaking when they are in use.

Where a battery is provided, a further sensor might be provided to monitor battery power. The sensor system could therefore also provide a low battery power signal in its transmission when a low battery status is detected to alert the operator of that fact.

The display or man-machine interface (MMI) in the cab (for indicating the sensor information, or coupler status information) can be programmed to provide its information in a number of ways, or just such that it interacts with the excavator's controls in a number of different ways.

In one system, the signals are translated into visual indicia such as lights or coupler status representations, such that a display can guide the operator through an accessory coupling or decoupling procedure by providing graphical indications when certain individual steps of that coupling or decoupling process have been achieved. This can be helpful since that information is not always possible to see from within the cab (e.g. the position of the pivoting latching hook). Alternatively, or additionally, the interface can provide excavator functionality lockouts (i.e. "limp modes") in response to certain detected situations, such as an incomplete coupling of an accessory to the coupler (e.g. just in the front jaw). In this regard, specific excavator or excavator arm movements can be restricted or disabled until the coupling procedure has been completed. Alternatively, engine or hydraulic power may be reduced, whereby digging or manoeuvring is made more difficult. That should dissuade the driver from commencing or continuing an improper use of the coupler/excavator.

One preferred feature, however, is that when no attachment pin is detected, full functionality for the excavator is allowed. That is because the coupler is usually fitted with a lifting eye 38, which is often used for lifting items on a chain or rope. To disable that function would be a significant inconvenience. Further, without such freedom to move in an uncoupled condition, manoeuvring the coupler and excavator to align the front jaw with a first attachment pin of a new accessory for coupling thereto would also be is made more difficult, which would also obviously be undesirable.

With regard to the limp modes, one such mode could be a low power mode in which the throttle is limited to a maximum of a quarter throttle. That could be for either the excavator's engine or just for the hydraulic pump.

It will also be observed that the sensor 44 for the hydraulic ram 36 could provide an additional overriding control, whereby in the event of the detection of a failure in that hydraulic system, that alone would be enough to cause a limp mode to be effected.

Certain additionally optional features are as follows:

To enable wireless transmissions to be recognised by the receiver 48, transmissions can be coded with unique identity information that can be transmitted for identifying the coupler/sensors from which the transmission had originated. Transmissions could perhaps also include details of the accessory that is connected to the coupler, e.g. accessory type information. That would be detectable by a sensor on the coupler that can read information from a transceiver on the accessory.

Duty cycle information, such as hours used or cycle completed, might be monitored by the control system, either at the coupler or at the receiver. That information could be logged at the coupler and transmitted to the receiver, or logged at the receiver, whereby accessories having a finite duty life can be tracked and repaired or replaced as and when necessary.

Likewise, other sensed information can be logged or transmitted, such as work-tool recognition information, excavator recognition information, pairing information, tool suitability information (e.g. tool capacities, types, or sizes), tool or coupler use information (e.g. current loading information), and tracking information (e.g. GPS positioning information) for allowing fleet or asset tracking to be automatically carried out, or for it to be discernable at a later date from stored information.

From the above disclosure, therefore, the present invention provides a coupler for coupling an accessory to an excavator arm of an excavator, the coupler comprising a first jaw that points in a generally longitudinal direction relative to the frame of the coupler, the jaw being for receiving a first attachment pin of an accessory and having a first sensor for detecting the presence of an attachment pin therein, the coupler further having a second jaw, or a latch, longitudinally spaced from the first jaw, and being for receiving a second attachment pin of the accessory, and having a second sensor for detecting the presence of an attachment pin therein. Other features may then be added to it as described above.

It will also be appreciated that this disclosure also provides for further embodiments in which the additional sensors replace one or the other, or both, of the first two sensors. In the most preferred embodiments, however, the sensors of the coupler, or a central transmitter, are adapted to transmit or send signals to a receiver for notifying the driver or operator regarding the coupling status of the coupler, or the loading status of the coupler, so as to keep the driver informed as to that status, or in more advanced embodiments, to allow the excavator to apply operational limitations to the control electronics/hydraulics when problems are identified.

Although the present invention has been described above purely by way of an illustrated example, and by way of possible alternative or additional features, it will be appreciated that modifications in detail may be made to the invention within the scope of the claims as appended hereto.

Claims

1. A coupler for coupling an accessory to an excavator arm of an excavator, the coupler comprising a first jaw that points in a generally longitudinal direction relative to the frame of the coupler, the jaw being for receiving a first attachment pin of an accessory, wherein a sensor is provided for that jaw for detecting the presence of an attachment pin in that jaw.

2. The coupler of claim 1, wherein the sensor is adapted to output a signal to signify the presence of an attachment pin in the j aw.

3. The coupler of claim 1 or claim 2, wherein the sensor is adapted to output a signal to signify no detected presence of an attachment pin in the jaw.

4. The coupler of any one of the preceding claims, in combination with a receiving unit or a transmitter, wherein the sensor's signal is transmitted or sent to the receiving unit, or to the transmitter, for allowing an indication of the sensed information to be passed to a user.

5. The coupler of claim 4, wherein the signals are transmitted or sent along a wire.

6. The coupler of claim 4, wherein the signals are transmitted or sent wirelessly.

7. The coupler of any one of the preceding claims, in combination with a display, the display, in use, being located within a cab of the excavator to whose arm the coupler is attached, wherein the sensed information from the sensor is displayed on the display

8. The coupler of claim 7, wherein the display is integrated into or onto an excavator's dashboard.

9. The coupler of any one of the preceding claims, wherein the sensor is one of, or a combination of one or more of, a strain sensor, a PTM (push-to-make) switch, a magnetic sensor, an optical sensor and a capacitance sensor.

10. The coupler of any one of the preceding claims, further comprising a second jaw or a latch, longitudinally spaced from the first jaw with respect to the frame of the coupler, for receiving or securing a second attachment pin.

11. The coupler of claim 10, wherein the second jaw or latch includes a pivoting or sliding latch for locking an attachment pin onto the coupler.

12. The coupler of claim 10 or claim 11, wherein a second sensor is provided for detecting the presence of an attachment pin in that second jaw or latch.

13. The coupler of claim 12, wherein the second sensor is mounted directly onto or into to a pivoting or sliding latch.

14. The coupler of claim 12 or claim 13, wherein the sensor is one of, or a combination of one or more of, a strain sensor, a PTM (push-to-make) switch, a magnetic sensor, an optical sensor and a capacitance sensor.

15. The coupler of any one of the preceding claims, wherein signals from the or each sensor is transmittable to a receiving unit with a coding, whereby the source or sources of the transmitted signals, with respect to which sensor they came from, is discernable by the receiving unit.

16. The coupler of claim 15, wherein a central transmitter transmits, in a single transmission, signals from two or more sensors, the transmission being coded such that the receiving unit can discern both the individual signals and the sources of those signals.

17. The coupler of any one of the preceding claims, provided in combination with an indicator unit for indicating sensed information to the user from the coupler, the indicator unit having a visual indicator for illustrating sensed information.

18. The coupler of claim 17, wherein the indicator unit has a light for the first jaw, the light illuminating when an attachment pin is sensed within the first jaw.

19. The coupler of claim 17 or claim 18, when dependent upon claim 12, wherein the indicator unit has a light for the second jaw or the latch, the light illuminating when an attachment pin is sensed within the second jaw or the latch.

20. The coupler of claim 18 or claim 19, wherein the or each light is green or red.

21. The coupler of claim 18, claim 19 or claim 20, wherein the indicator also has a light for illuminating when an attachment pin is not sensed, wherein that light is a different colour to the other light.

22. The coupler of any one of the preceding claims, further comprising one or more additional sensor.

23. The coupler of claim 22, further comprising an actuator for operating the coupler's latching mechanism, wherein a third sensor is incorporated into or onto the actuator.

24. The coupler of claim 23, wherein the sensor senses the extension state of the actuator.

25. The coupler of claim 23 or claim 24, wherein the actuator is a hydraulic ram that is mounted within the frame of the coupler.

26. The coupler of claim 25, wherein a sensor in or on the coupler senses the hydraulic pressure within the ram.

27. The coupler of any one of the preceding claims. Further comprising a sensor of a work-tool recognition system for identifying information regarding an attached accessory.

28. The coupler of any one of the preceding claims, wherein a sensor is provided on the coupler for detecting, in use, a loading applied to an attached accessory.

29. The coupler of any one of the preceding claims, wherein a sensor is provided on the coupler for detecting, in use, a loading applied to a lifting eye of the coupler.

30. The coupler of any one of the preceding claims, further comprising a GPS position sensor, and means for storing or transmitting location information.

31. A method of notifying to a driver of an excavator the accessory engagement status of a coupler attached to an end of the excavator's arm, wherein the coupler is in accordance with any one of the preceding claims, comprising sensing the accessory engagement status of the coupler using the or each sensor and transmitting or sending that sensed information to a notification unit near the driver.

32. The method of claim 30, wherein a red light on the notification unit signifies an unsafe accessory engagement status.

33. The method of claim 30 or claim 31, wherein the sensor system or the notification system is linked to the hydraulic control system of the excavator, whereby if an unsafe accessory engagement status is sensed, the hydraulic system's output is restricted.

34. The method of any one of claims 30 to 33, wherein the sensor system or the notification system is linked to the engine management system of the excavator, whereby if an unsafe accessory engagement status is sensed, the engine's power is restricted.

35. The method of any one of claims 30 to 34, wherein the coupler is in accordance with any one of claims 1 to 29.

36. The method of any one of claims 30 to 35, wherein the coupler stores in a memory information regarding the accessories and/or excavators to which it is, and/or has been, attached.

37. The method of any one of claims 30 to 36, wherein the coupler stores in a memory information regarding the location or address at which accessories and/or excavators are being, and/or have been, attached thereto.

38. The method of any one of claims 30 to 37, wherein the coupler transmits information regarding the accessories and/or excavators to which it is, and/or has been, attached, for receipt by a receiver in or on an excavator.