GB2446138A

GB2446138A - Coupler for an excavator

Info

Publication number: GB2446138A
Application number: GB0702082A
Authority: GB
Inventors: Gary Miller; Ronald Keith Miller; Gary Pendleton; Howard Reay
Original assignee: Miller UK Ltd
Current assignee: Miller UK Ltd
Priority date: 2007-02-02
Filing date: 2007-02-02
Publication date: 2008-08-06
Also published as: GB0702082D0

Abstract

A coupler for attaching an accessory to an excavator arm comprises a jaw 26 for receiving an attachment pin of the accessory, a pivoting latching device 32 associated with the jaw 26, a pivot 54 for the latching device 32, a toggle 46 movable between an open position and a latch back-up position in which it serves to resist the pivoting of the latching device 32 from its latched position into an unlatched position by engaging with a non latching end 52 of latching device 32, on the opposite side of the latching device pivot from the latching end. The toggle 46 may be pivotable and gravity operated. The latching device 32 may be biased to the latched position by spring 68. A sprung ball detent (72 fig 26) may also be provided for holding the latching device 32 in a latched position until it is intentionally moved from that latched position, the sprung catch being located in the latching member 32 and engaging with a hole in a wall (76 fig 28) of the coupler.

Description

COUPLER

The present invention relates to a coupler for coupling an accessory to an excavator arm rfn eyi-',u,tj-,r fln ii4 Qrbr, nuIi-I}p in pyv2tnr hiir'kpt Couplers for coupling accessories to the excavator arm of an excavator are well known in the art. Indeed many prior art patents describe such couplers. See, for example, GB2330570, GB2177674, EP184282, US2005169703A1, US6699001 and EP1473467.

The coupler in GB2330570 comprises a top half that is connectable to an excavator arm using two attachment pins (via two pairs of holes provided for those attachment pins).

The bottom half of the coupler is then for engaging two further attachment pins, on the accessory. For that purpose that bottom half comprises two jaws, rather than holes.

Those jaws engage respective ones of those two further attachment pins of the accessory.

A first of the two jaws is usually referred to as a front jaw. Its opening (for receiving the first or front attachment pin) is directed generally 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 (or, more precisely, usually at an angle upwards from that line, perhaps at an angle of up to 15 ).

The second jaw is usually referred to as a rear jaw. It points downwardly, i.e. in a direction that is generally perpendicular to the front jaw.

The rear jaw has an associated latching hook. The latching hook can be pivoted between a latched position and an unlatched position. In the latched position, the opening of rear jaw is at least partially closed by the latching hook. In the unlatched position, however, the latching hook is usually fully retracted so as to leave the jaw's opening open so that the attachment pin can be removed from the jaw downwardly.

The coupler also features a blocking bar which is adapted to fall under the influence of gravity (during normal, in-use, orientations of the coupler) into a blocking position in front of the 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 normal, in-use, orientations, rather than upside down. 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 some form of urging means would be provided for lifting the blocking bar from its blocking position.

One such urging means could be a small hydraulic ram.

During normal use, i.e. when digging with a bucket, very high forces can be loaded onto the latching hook by the attachment pins of the accessory. Occasionally those forces 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 prevents the blocking bar from buckling under those loads.

A similar coupler is disclosed in US6699001. However, in that document, the latching hook of GB2330570 is replaced by a sliding plate and the locking arm serves the function of the blocking bar of GB2330570, that locking arm falling in front of the plate.

Another similar coupler is disclosed in EP1473467. In that coupler, latching bars are provided to function as the blocking bar of GB2330570. Further, rather than directly engaging in front of the latching hook, those latching bars instead engage behind pins that extend forwardly away from the latching hook, i.e. towards the front jaw.

In each of these couplers, therefore, there is one or more blocking bar, or the like, positioned between the front jaw and the rear jaw. Further, however, an actuator (usually either a hydraulic ram or a large screwthread), for moving the latching hooks or sliding plates, between their latched and unlatched positions, is also positioned in that same area of the couplers. The blocking bars, and the like, therefore, need to be positioned to one or both sides of that actuator. As a result, couplers featuring a blocking bar or the like to date have needed to be relatively large or wide. Therefore, blocking bar couplers can be difficult to make really small, whilst still reliable. It would be desirable, therefore, to provide a new design of coupler that can be made both small and narrow, but which coupler still features precautionary, effective, but generally redundant, latch back-up mechanisms.

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 half for connecting to the excavator arm and a second half for connecting to the accessory, the second half comprising: ajaw for receiving therein an attachment pin of the accessory; a pivoting latching device associated with the jaw; a pivot for the latching device about which the latching device is pivotable between a latched position and an unlatched position, and wherein, in the latched position, the jaw is at least partially closed by the latching device for holding the attachment pin within the jaw; and a gravity operable toggle movable between a latch back-up position and an open position, the toggle, when in its latch back-up position, serving to resist a pivoting motion of the latching device from its latched position into an unlatched position; wherein the latching device has a latch end and a non-latch end, the latch end extending away from the pivot in a first direction that extends generally towards the jaw whereby the latch end can at least partially close the jaw when the latching device is in its latched position, and the non-latch end extending away from the pivot in a second, different, direction, which direction is generally away from the jaw, the toggle serving to resist the pivoting of the latching device from its latched position into an unlatched position by having a surface that is adapted to engage against the non-latch end of the latching device.

Preferably the second direction, relative to the first direction, is rotated about the pivot by an angle of between 90 and 270 . Most preferably it is rotated by an angle of about 180 , i.e. the non-latch end extends from the pivot in a direction that is directly opposite to the direction that the latch end extends from the pivot. The angles, however, may be customised to suit any particular embodiment since the required angles will depend upon the geometry of the components of the coupler.

Preferably the non-latch end of the latching device comprises a fiat bearing surface against which the surface of the toggle can bear for resisting the pivoting of the latching device from its latched position into an unlatched position. Preferably that bearing surface is provided on a flange that defines the non-latch end. Preferably the bearing surface extends more radially than circumferentially relative to the pivot.

Preferably the latching device is a hook.

Preferably the toggle is an elongate member.

Preferably the accessory couples to the coupler by a two-point attachment, the jaw being the first one of those two points. Preferably the jaw is a first jaw and the second point is a second jaw. Preferably the second jaw faces a different direction to the first jaw.

Preferably the second jaw faces a direction that is perpendicular to the direction of the first jaw.

The second jaw is preferably always open. However, it might alternatively be provided with a second latching device. That second latching device may be power-operated, spring biased or gravity operated.

An imaginary line extending between the two points of attachment extends in a longitudinal direction of the coupler, i.e. lengthwise. A forward facing jaw faces that longitudinal direction.

The attachment pin's axis, when that pin is secured in the first jaw, defines the transverse direction of the coupler, i.e. the width of the coupler.

The height of the coupler is the dimension of the coupler that extends through both the first and the second halves of the coupler. The first half of the coupler is known as the top half of the coupler (i.e. even when the coupler is inverted). The second half is known as the bottom half (also even when inverted). A downward facing jaw, therefore, extends out of the bottom of the second half of the coupler.

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

Preferably the second jaw, where provided, faces substantially forwards or generally longitudinally, i.e. neither significantly towards the first half of the coupler, nor significantly towards the second half of the coupler. Preferably the opening also faces generally longitudinally. The jaw, and its opening, may point at a slightly upwards angle from that longitudinal direction, but preferably by no more than 150 from that forwards direction, i.e. relative to the longitudinal/transverse plane of the coupler.

The or each jaw may consist of a solid, one-piece jaw with a generally constant transverse cross section, although a variance from that constant cross section might be provided to accommodate a or the latching device for that jaw.

In an alternatively design, the or each jaw has a non-constant transverse cross section, perhaps being formed from a pair ofjaw parts, with a first jaw part being on one side of the coupler and the other jaw part being on the other side of the coupler (for example formed in the sideplates of the coupler).

The latching device for the first jaw will usually be positioned substantially in the middle of the jaw, i.e. between the two jaw parts. However, the latching device may feature two hooks each positioned either side of the middle.

The or each jaw, or jaw part, will usually be provided with a reinforced or hardened steel insert to provide additional strength for the jaw. That additional strength assists the jaw to accommodate the heavy loading that will be applied to it during the use of the coupler.

Preferably the accessory is an excavator bucket.

Preferably the toggle will disengage from its latch back-up position into an open position under the influence of gravity if the coupler is inverted such that the second half of the coupler is physically, directly and wholly above the first half of the coupler, i.e. such that the longitudinal direction of the coupler is horizontal. The required angle of inversion, however, can be governed or controlled by the chosen orientation of the toggle within the coupler.

Preferably the toggle is a pivoting toggle, mounted for rotation about a second pivot, that second pivot being spaced from the first pivot (of the latching device). The relative positions of the second pivot, the toggle and the toggles's centre of gravity, and their positions relative to the non-latch end of the latching device, define the orientations of the coupler at which gravity would act upon the toggle so as to cause it to rotate into and out of its latch back-up position.

As the toggle is merely a generally redundant back-up mechanism for the latching device of the coupler, in its latch back-up position, the toggle is unlikely actually to engage against the non-latch end of the latching device. Instead it simply sits or rests next to it.

Preferably the disengagement of the toggle from its latch back-up position can occur, under the influence of gravity, through a range of angles of inversion, i.e. through an arc of rotation of at least 20 degrees. Preferably that range of angles extends at least 100 either side of a direct inversion (i.e. an orientation of the coupler in which the second half of the coupler is directly and fully above the first half of the coupler). More preferably the range of angles extends at least 20 either side of a direct inversion. The range might even extend up to 35 or even 45 either side of a direct inversion.

In preferred embodiments, the gravity-influenced disengagement occur through a range of angles of inversion that is not symmetrically arranged either side of a direct inversion.

For example, the range of angles may extend up to 45 in one direction (but more preferably to no more than 35 in that direction), but even further in the other direction, e.g. to 90 in the other direction, or even beyond that, for example up to as much as 135 in that other direction. Preferably, however, the range is limited by the geometry or arrangement of the components to an angle of no more than 125 in that other direction.

It can be observed that at angles beyond 9 0 from a direct inversion, the coupler is no longer actually in a state of inversion.

The latching device is preferably hiasable towards its latched position by a biasing device such as a spring (e.g. a coil spring, a compression spring or a plate spring).

Alternatively, or additionally, the latching device may be biased into that position by gravity (e.g. when the coupler is in a non-inverted condition, such as a level, non-inverted, state of orientation. A further arrangement may have a power actuator (e.g. a hydraulic ram or a screwtbread) for biasing the latching device towards its latched position.

Preferably the biasing device for the latching device is located in a position lying generally between the two points of attachment of the coupler, such as in GB233 0570, i.e. generally between the first jaw and the second jaw. However, no blocking bar will be positioned between the first jaw and the second jaw. Instead, the toggle of the present invention is provided, that toggle being positioned in its novel position -away from the biasing device. That avoids any overcrowding of that space between the first jaw and the second jaw, whereby the coupler can be made smaller or narrower.

Preferably the toggle is positioned on a rearward side of, or above, the first jaw. The second point of attachment (e.g. the second jaw) then lies on a forward side of that jaw.

This works where the first jaw is a rear jaw.

Where the toggle is a pivoting toggle, its pivot, i.e. the second pivot, is located further rearward in the coupler, and lower in the coupler, than the pivot for the latching device.

Preferably the latching device's pivot is located above and rearward of the latch end of the latching device, and positioned relative to the jaw such that the latch end has to rotate downwardly and rearwardly, relative to the body of the coupler, in order to find a latching position against an attachment pin within the jaw. Preferably that location for the pivot is directly above the jaw.

Preferably the toggle is an elongate member that sits, in its latch back-up position, at an angle of approximately 45 upwards and forwards from its pivot relative to the longitudinal/transverse plane of the coupler, and at a steeper angle when it is instead in an open position, That steeper angle may perhaps be an angle of about 60 . Alternative toggle designs, however, might have a latch back-up position angled at between 300 and 60 from the horizontal, i.e. relative to the longitudinal/transverse plane of the coupler.

Preferably the latching device has a hole in it for receiving a latch disengagement bar therein, whereby, with the latch disengagement bar, the latching device can be forced to rotate about its pivot by overcoming its biasing force. That will allow the latching device to be disengaged manually from its latched position into an unlatched position. However, before that can be done it is first necessary to move the toggle from its latch back-up position into an open position. That may be done with the end of the latch disengagement bar or by hand. This is particularly useful for small and inexpensive couplers where their size allows the manual manipulation of their components, i.e. they are not too large or heavy for manual manipulation, and where those cost restrictions do not permit the provision of a hydraulic rain or a screwthread within the coupler for automating the movement of the latching device.

In a preferred embodiment, the body of the toggle covers at least part of the hole in the hook. Then, as the latch disengagement bar is put into the hole, the toggle will automatically be raised or moved by its engagement by the latch disengagement bar.

That raising or moving of the toggle preferably is sufficient to free the toggle from its latch back-up position so as to allow rotation of the hook.

The toggle's surface is an engagement surface that preferably will directly engage the latching device if it ever needs to resist the rotation of the latching device. An intermediary element, however, might be present, whereby the toggle will not directly engage with the latching device, but instead it will engage the intermediary element, which will in turn will engage the latching device.

More than one engagement surface may be provided on the toggle, e.g. a stepped arrangement, whereby the toggle may serve to resist the rotation of the latching device from two or more different latched positions. Conversely, the flange of the latching device may have more than one bearing surface, whereby a single engagement surface of the toggle can resist the rotation of the latching device from two or more different latched positions. These features provide an element of adjustability for the toggle's effect, which allows the coupler to be used with a variety of accessories, such as ones having different pin spacings, without reducing the capability of, or rendering ineffective, the redundant latch back-up mechanisms.

Preferably the toggle can rely purely upon gravity for its movements, relying simply on rotation of the coupler from one orientation into another orientation, for example by the excavator arm's hydraulics, for affecting its range of motion. As such it will have no mechanical biasing devices associated to it, and can be operated without direct manual intervention. A spring bias, however, may be provided for the toggle for altering slightly the range of angles of inversion necessary for affecting those motions of the toggle. For example, with a light spring bias into the latch back-up position, a more complete inversion of the coupler might be required to move the toggle into an open position since only then would gravity overcome the biasing force provided by the spring.

Preferably the pivoting latching device has a wall for opposing a fixed wall of the coupler when the latching device is in a latched position, those two walls comprising a sprung catch and an opposing hole, the sprung catch being adapted to engage with the hole when the latching device is in a latched position, and wherein, upon movement of the pivoting latching device from that latched position into an unlatched position, the sprung catch is adapted to disengage from the hole.

Preferably the sprung catch is in the pivoting latching device and the hole is in the fixed wall of the coupler. Alternatively, however, the sprung catch may be in the fixed wall of the coupler and the hole may be in the pivoting latching device.

Multiple holes might be provided for providing multiple different latched positions.

The sprung catch and hole arrangement provides a further latch mechanism for the pivoting latching device. It helps to hold the pivoting latching device in its latched position until it is desired to retract it into a non latched position. With this additional feature, to retract the latching device, the bias of the spring of the catch has to be overcome by an applied unlatching force, such as that provided by a hydraulic ram, or by a latch disengagement bar.

According to a second aspect of the present invention there is provided a coupler for attaching an accessory to an excavator arm of an excavator, the coupler comprising a first half for connecting to the excavator arm and a second half for connecting to the accessory, the second half comprising: a jaw for receiving therein an attachment pin of the accessory; a latching device associated with the jaw, the latching device being moveable between a latched position, in which the jaw is at least partially closed by the latching device for holding the attachment pin within the jaw, and an unlatched position, in which the attachment pin of the accessory can be removed from the jaw; wherein the latching device has a wall for opposing a fixed wall of the coupler when the latching device is in a latched position, the t%vo walls comprising a sprung catch and an opposing hole, the sprung catch being adapted to engage with the hole when the latching device is in a latched position, and wherein, upon movement of the latching device from that latched position into an unlatched position, the sprung catch is adapted to disengage with the hole.

Preferably the catch contains a compressed coil spring. The spring provides a bias that has to be overcome in order to disengage the sprung catch from the hole.

Preferably the hole is in the fixed wall of the coupler and the sprung catch is in the wall of the latching device. Alternatively, however, the hole may be in wall of the latching device and the sprung catch may be in the fixed wall of the coupler.

Preferably the two walls are substantially flat and parallel to each other.

Preferably the latching device is a pivoting latching device, and most preferably the latching device is a pivoting hook. In an alternative arrangement, the latching device is a sliding latching device.

Preferably the sprung catch comprises a ball bearing, a spring and a sleeve. Preferably the sleeve has a closed end wall and a partially occluded open end at its opposite end.

Preferably the ball bearing and the spring are contained within the sleeve such that the spring bears against the closed end wall and the ball bearing extends partially out of the open end of the sleeve. The partial occlusion of the open end may be by means of a formed or rolled flange, the resulting opening having a smaller diameter than the ball bearing.

The sleeve may have an adjustable length. By shortening the sleeve, a greater biasing force against the ball bearing can be provided, whereupon a greater latching device retention capability can be provided with the hole -a larger force will be required for moving the latching device from its latched position into an unlatched position.

Preferably the closed end wall features a cap that screws on to a cylindrical side wall of the sleeve to close the second end of that cylinder. The rotational adjustment of that cap can adjust the length of the sleeve.

Multiple holes may be provided to allow a plurality of different accessories, each having different attachment pin spacings, to be accommodated by the coupler. Each hole can define an alternative latched position.

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figures 1-9 illustrate a preferred method for coupling an accessory onto a coupler of the present invention; Figure 10 illustrates the coupler in an inverted orientation and in which the toggle is in a latch back-up position; Figures 11-17 illustrate a preferred method of manually disengaging the accessory from the coupler; Figures 18-21 are cut-away perspective views of a preferred embodiment of the present invention, having a hydraulic ram for actuating the latching device; Figures 22-25 are cut-away perspective views of that embodiment, but in which the hydraulic ram has been removed; and Figures 26-31 show a modified arrangement for the pivoting latching device in which a ball detent feature is provided.

Referring first of all to Figure 1, a coupler 10 in accordance with a first embodiment of the present invention is shown. Also, two attachment pins 14, 28 of an accessory are illustrated. The rest of the accessory, which may be a bucket such as that disclosed in GB2362371A, is not shown simply for clarity.

The coupler 10 has a first half 16 (the top half) and a second half 18 (the bottom half).

The first half 16 has a pair of sideplates 22 (one shown), each having two holes 20, 21 for attaching the coupler 10 to an excavator arm (not shown) of an excavator by using two attachment pins (not show). The holes 20, 21 in the sideplates 22 are a front hole 20 and a back hole 21.The attachment pins are passed through the holes 20, 21 and through a pair of correspondingly aligned holes in the attachment arm, whereby the coupler 10 is then coupled to the excavator arm by the attachment pins.

The second half 18 of the coupler 10 is for attaching to the accessory using the two illustrated attachment pins 14, 28. However, instead of the two holes 20, 21 of the first half of the coupler, there is a pair ofjaws 24, 26 for that purpose. The first jaw is a front jaw 24 and the other jaw is a rear jaw 26. They will usually be used to engage the front attachment pin 14 and the rear attachment pin 28 of the accessory, respectively.

However, the accessory can usually be connected to the coupler 10 the other way around, i.e. front-to-back.

The front jaw features an opening 23, between a lower jaw 25 and an upper jaw 27. The lower jaw has an upwardly projecting lip 29 for partially occluding the opening. That is to catch an attachment pin 14 if it was to start to slip out of the front jaw 24, as explained in greater detail in GB0617394.2, the disclosures of which are incorporated herein by way of reference. That lower jaw, in this preferred embodiment, also projects further forwards than the upper jaw. This gives the jaw a wider opening to counteract the effect of the occluding lip 29.

An imaginary line extending between the centres of the two holes (20, 21) in the sideplates 22 defines the longitudinal direction of the coupler 10, i.e. the coupler's length. The axes of the holes, however, extend transversely across the coupler, i.e. across the width of the coupler. Those lines together define a longitudinal/transverse plane of the coupler 10. In the following description, when the coupler 10 is said to be in a level orientation, that plane is horizontal. Further, deviations from that level orientation will be indicated in terms of the angle that the coupler has been rotated about those axes from that level orientation, with the rear end lifting being a clockwise rotation and the front end lifting being an anti-clockwise rotation.

In Figure 1 (and in Figure 2), the coupler 10 has been rotated clockwise through an angle of about 35 from the level orientation. Therefore it is in a non-level orientation. That reorientation, however, has reoriented the opening 23 into a substantially vertical arrangement, thus providing a widest possible opening in the vertical plane. This is not essential. However, it will help a driver of the excavator to align and mount the front jaw 24 onto the front attachment pin 14 of the accessory. That is usually done by bringing the coupler 10 forward and down 12 towards the front attachment pin 14 of the accessory until it finally reaches the position of Figure 2, with the attachment pin 14 resting tightly against the back 31 of the front jaw 24.

Although the coupler has been shown to be reoriented by an angle of approximately 35 , other angles such as angles in the range of 5 to 50 would also allow the coupler to engage with that front attachment pin 14.

Once the front jaw 24 has been engaged with the front attachment pin 14, as shown in Figure 2, the operator will then commence an anti-clockwise rotation 30 of the coupler 10, to bring the rear jaw 26 of the coupler 10 down towards the rear attachment pin 28 of the accessory.

Eventually, as shown in Fiaure 3, the rear pin 2X will contact the coupler. The contact will be against a pivoting latching hook 32 that is provided for the rear jaw 26. The pivoting latching hook 32, by default,is biased by a spring into a position in which it partially closes the rear jaw 26. That position is referred to as a latched position since an attachment within the jaw 26 would be latched within that jaw 26 when the hook 32 is in that latched position.

In that latched position, at the opening of the rear jaw 26 (a downwardly facing jaw), the latching hook 32 has an outside, lower surface 34. It is that lower surface 34 that will bear against the rear attachment pin 28 once the rear of the coupler 10 has been lowered sufficiently.

Since the rear attachment pin of a bucket is usually at a different height to the front attachment pin of a bucket, the two pins 14, 28 are shown at different heights.

In the illustrated embodiment, due to the different heights of the pins 14, 28, the coupler 10 will be substantially level at this first point of contact.

Next, as shown in Figure 4, the coupler 10 and the accessory are lifted 36 by the excavator. The coupler 10 is also further rotated 38 anticlockwise. In Figure 4, the angle of rotation is about 45 anti-clockwise from a level orientation. In that orientation, the weight of the accessory will cause a significant force 40 to be imposed against the lower surface 34 of the latching hook 32.

Since that lower surface 34 is angled or rounded, that force 40 in turn provides a force component on the hook 32 that will tend to bias the hook 32 out of its latched position into an unlatched position by rotating the hook about its pivot 54. However, in the orientation of Figure 4, such rotation of the latching hook 32 is resisted by a toggle 46.

Further, that rotation is countered by the bias from the spring.

In order to overcome the bias from the spring, the coupler is further rotated 44 anti-clockwise, for example to the orientation of Figure 5 (rotated through an anti-clockwise angle of about 75 from the level orientation). That further rotation 44 of the coupler 10 increases the force 40 against the hook 32, and further it allows the toggle 46 to go over-centre and therefore to fall away from its first position, a latch back-up position, into a new position, an open position, as disclosed in further detail below.

That continued rotation 44 will also eventually increase the force 40 acting on the hook sufficiently so as to overcome the bias of the spring, thereby causing the hook 32 to rotate out of its latching position. If the weight of the coupler is insufficient alone to cause the spring bias to be overcome, then the operator might jar the coupler 10 and the accessory together slightly, such as by rapidly curling and uncurling the coupler 10 a small amount. Although effective for overcoming that bias, that jarring action is not shown.

Once the force 40 against the hook 32 has exceeded the biasing force of the spring, the latching hook 32 will rotate out of its latching position to clear the opening of the rear jaw 26, whereupon the rear attachment pin 28 will enter the rear jaw 26. This is shown in sequence in Figures 6 and 7. Figure 6 shows the hook passing the nose of the latching hook and Figure 7 shows the attachment pin 28 fully within the jaw 26, with the sprung latching hook 32 closed back, by its sprung bias, into the latching position. In that position, the attachment pin 28 is secured within the jaw 26 by the latching hook 32.

At that point, the coupler can then be rotated 56 in a clockwise direction back towards the level orientation and the accessory is then ready to be used.

As it is being rotated 56 back towards the level orientation, the coupler once again becomes oriented such that the toggle will again go over-centre, as shown in sequence in Figures 8 and 9. In Figure 8, the angle of rotation of the coupler 10 is about 15 anti-clockwise from the level orientation. At that point, the toggle extends vertically above its pivot 48. Then, any further significant clockwise rotation would take the toggle 46 over-centre, whereupon, as shown in Figure 9, it falls back down into a latch back-up position. The toggle 46 then will serve to resist inadvertent rotation of the latching hook 32 out of its latching position.

The tnuole i n e1nnoite member 46 th2t i nivAth1e under the influien'p Af mavit, or ---a----------. --:--. ------------.-----.--. a-j, by hand, about its pivot 48. It can pivot between a latch back-up position, as shown in Figures 1 to 4 and an open position, as shown in Figures 5 to 8. That pivotal movement, when occurring under the influence of gravity, only occurs when the toggle 46 has been rotated (by rotation of the coupler 10, e.g. by the excavator arm) sufficiently over-centre for gravity to provide a sufficient moment to overcome any resistance to the pivotal movement.

Whilst in its latch back-up position, as shown in Figures 1 to 4, 9 and 10, the end 50 of the toggle 46 is located closely adjacent to a flange 52 that extends away from the pivot 54 of the latching hook 32. That flange 52, which defines a non-latch end of the hook 32, extends in the opposite direction to the latch end of the latching hook 32, i.e. generally away from the rear jaw 26.

As a result of that position of the end 50 of the toggle 46, the toggle will serve to resist any significant rotation of the latching hook 32 from its latched position.

The toggle 46, when the coupler 10 is in its level orientation, and when it is in its latch back-up position, as shown in Figure 3, lies at an angle of about 50 from the level orientation. It thus points upwards and forwards. Its design, i.e. its position and orientation relative to the coupler, the flange 52 of the latching hook 32, the pivot 54 of the latching hook 32 and its own pivot 48, provides an efficient means for preventing inadvertent rotation of the latching hook 32 from a latched position into an unlatched position during normal orientations of use of the coupler, especially those orientations ranging from a 45 clockwise rotation, as in Figure 1, to a 45 anti-clockwise rotation, as in Figure 4. Indeed, it will provide its function through even an extended range of clockwise rotations, including angles at which an attached bucket would be being emptied, such as that shown in Figure 10, i.e. where the angle of rotation is about 120 . It can even function at greater angles than that, e.g. to an angle of about 140 . The function of resisting rotations of the latching hook, however, is not so widely provided for rotations of the coupler in an anti-clockwise direction. Nevertheless, the illustrated maximum effective angle of about 45 in that direction, however, is sufficient since further rotations in that direction place the accessory and the coupler 10 into a crowd flflitiAfl whit4i nnfir,n}, nn r1r9(.t 21,ic r.tIisr thsn (lflrincy tr2nc,-2fIc,r, Piirfhr in t---.

that crowd position, the weight of the accessory holds the accessory onto the coupler anyway since the front jaw points vertically upwards. Thus the coupler of the present invention serves to secure an accessory onto an excavator in a secure and reliable maimer, and provides a coupler that is simple to use to that effect.

Referring now to Figures 11 to 17, the decoupling of the accessory from the coupler 10 is shown using a latch disengagement bar. In other embodiments, however, a power operated actuator 70 might be provided for powering the latching hook 32, whereby that latching hook can be power driven (i.e. pulled) from its latched position to an unlatched position, rather than needing the manual operation affected by the latch disengagement bar.

The decoupling procedure for this embodiment of the invention is a substantially manual procedure. It uses both the latch disengagement bar 58 for manipulating the working mechanism of the coupler 10 and the excavator/excavator arm for rotating or lifting the coupler 10. The use of the excavator/excavator arm is preferred since couplers are usually too heavy to manipulate relative to the accessory by hand.

Referring first of all to Figure 11, a coupler 10 is shown having the attachment pins 14, 28 of an accessory coupled into the jaws 24, 26 of the coupler 10. Further, the toggle 46 is in a latch back-up position, i.e. behind the flange 52 of the latching hook 32. Although not shown, the coupler 10 is also preferably oriented either such that the accessory (for example a bucket) is sitting on the floor with its base flat on the ground such that when the accessory is released from the coupler 10, it will not move on the ground.

Alternatively the accessory ca be slightly raised from the floor, whereby the rear pin 28 can readily disengage itself once the latching hook is released into a non-latching position. Preferably, the coupler's orientation is such that the coupler 10 is angled approximately 8 anti-clockwise from a level orientation.

Before the latching hook 32 can be unlatched from the rear attachment pin 28, the toggle 46 first needs to be moved into an open position. That is done manually using the latch disengagement bar 58 -a long bar having an end that is adapted to fit within an aperture that is provided in the latch end of the pivoting latching hook 32 In moving the toggle 46, that aperture 60 in the latch end of the pivoting latching hook 32 is also uncovered to provide access to the aperture 60. In this arrangement, the toggle 46 also serves to keep the aperture 60 clear of dirt and mud during the use of the coupler 10 since the aperture 60 is covered by the toggle.

The movement of the toggle, as illustrated, is a vertical or pivoting movement.

However, in an alternative embodiment it might be a sideways movement, e.g. by sliding it along its pivot 48, perhaps against the bias of a spring (not shown). Such a movement could also move the toggle into an open position.

Another alternative arrangement might involve a hole (not shown) in the toggle 46 for providing access to the aperture 60 in the latching hook, the hole perhaps only being in registration with the aperture once the toggle has been moved into an open position.

Whichever of the above alternatives is used, however, access to the aperture 60 in the hook is needed for the bar 58, as is the movement of the toggle 46 into an open position.

As illustrated, the toggle is pivoted out of its latch back-up position into a position it might take up if the coupler had been inverted. The end of the bar 58 can then be positioned into the aperture 60 of the latching hook.

Next, as shown in Figure 13, the latch disengagement bar 58 is rotated 62 downwardly to rotate the latching hook 32 about its pivot 54 into an unlatched position. Once in that position, if the bucket is not already lifted, the excavator is operated to lift the coupler and accessory slightly. As shown in Figure 14, that causes the rear attachment pin 28 to move out of the rear jaw 26 due to the centre of gravity of the accessory causing a relative rotation of the accessory about its still captured front attachment pin 14. If the coupler and bucket had already been lifted, however, the rear pin 28 would have simply dropped free of the rear jaw 26.

Instead of lifting the coupler, it would alternatively be possible just to rotate the coupler clockwise relative to the accessory. That would have the same effect of removing the rear pin 28 from the jaw 26. Such a rotation of the coupler would be provided by the excavator.

Once the rear attachment pin 28 has been released from the rear jaw 26, the latch disengagement bar 58 can be removed from the aperture 60 of the latching hook 32 and out of the coupler 10, as shown in Figure 15. That will result in the latching hook 32 simultaneously returning to a latching position (either under the effect of gravity or under the effect of the biasing force provided by the spring -e.g. see Figure 22). The weight of the accessory can then be rested against the floor, if not already done.

Next the front attachment pin 14 is disengaged from the front jaw 24. That can be done by further rotating 66 the coupler 10 anti-clockwise in combination with a rearward movement 67 of the coupler 10 relative to the accessory, as shown in Figure 16. Again the excavator is operated for these manipulations of the coupler 10 relative to the accessory.

The result, then is that the coupler 10 has been decoupled from the accessory, as shown in Figure 17.

Referring now to Figures 18 to 21, an alternative embodiment of coupler 10 is shown. It has the same features as the coupler 10 of Figures 1 to 17. However, the biasing spring 68 for the latching hook is shown. Also, however, the latching hook 32 has a hydraulic piston 70 for power operation of the latching hook 32 into and out of its latched position.

The aperture 60 is again shown for use of a latch disengagement bar 58. However, its use is optional, rather than preferred. The aperture 60 might even be omitted, although it might be useful in the event of a hydraulic piston failure, since its presence will allow the coupler 10 still to be decoupled from an accessory.

Referring next to Figures 22 to 25, another coupler is shown, but this time without a hydraulic piston 70. This design operates in the manner disclosed above in relation to Figures 1 to 17 and is well suited for smaller and low-cost couplers due to the simple, purely mechanical design.

Referring finally to Figures 26 to 31, a modified version of the coupler is disclosed. It has a ball detent feature fitted to it. As shown in Figure 26, that ball detent feature comprises a sprung catch 72 in a side wall 74 of the hook 32 that opposes and engages with a hole in a fixed wall 76 of the coupler 10 for providing an additional latching force forthehook32.

In this embodiment, the side wall 74 of the hook 32 is a flat side wall that runs parallel to a fixed wall 76 of the coupler 10. That fixed wall 76 is also flat, at least in that region of the coupler. See Figure 28, 29 and 30.

The fixed wall 76 has a hole 78 in it. That hole 78 is open towards the side wall 74 of the hook 32. Similarly, the hook 32 is provided with a hole 80 for receiving the ball detent feature 72 as shown in Figure 31. The two holes extend transversely across the coupler.

The sprung catch 72 may comprises a cap 82 having a slot therein for adjusting the position of the sprung catch within its hole 80 with a screwdriver (not shown). The sprung catch 72 would then also comprise a cylinder 84 onto which the cap 82 is attached (for example by means of a screw thread, not shown).

The cylinder 84, at its opposite end, has a formed or rolled flange 86 that partially occludes the open end of the cylinder. That flange 86 retains a ball bearing 88 within the cylinder 84. The ball bearing 88 forms a ball catch and is for locating within the hole 78 in the fixed wall of the coupler to provide the additional latching force for the hook 32.

The ball bearing is biased towards the open end of the cylinder 84 by a spring 90, also retained within the cylinder 84. The spring 90 (a compression coil spring in this embodiment) bears against the cap 82 and the ball bearing 88, whereas the ball bearing 88 bears against the spring 90 and the end flange 86 of the cylinder.

Due to the size of the open end of the cylinder, as compared to the size of the ball bearing 88, the ball bearing 88 will only partially extend out of the open end of the cylinder 84 and will be biased into that position by the spring 90. A stiffer spring (or a more compressed spring, such as by shortening the cylinder) will create a greater bias force for the ball bearing. As a result, the ball catch will provide a stronger latching force for the hook 32 within the hole 78.

In an alternative arrangement to the two piece construction for the sprung catch 72 described above, the cap and cylinder can be unitary, with the formed or rolled flange 86 being formed after the ball bearing 88 and spring 90 have been inserted into that unitary sleeve.

The sprung catch 72 may be either press-fitted or screwed into the hole 80 of the hook 32. Preferably, however, the depth of that insertion is adjustable, whereby the effectiveness of the ball detent feature can be adjusted by moving the sprung catch longitudinally within the hole 80 -the further in it goes, the less retention is provided, whereas if it is too far out, it may jam against the fixed wall of the coupler.

Figure 26 shows the sprung catch 72 extending slightly out from the side wall 74 of the hook 32. Figure 27 is then the same view of that arrangement. However, the hook 32 has been removed for clarifying the shape of that sprung catch 72. Figure 28 similarly shows that same arrangement, and again the hook has been removed for clarity. Its view, from below, clearly shows the sprung latch 72 in engagement with the fixed wall 76 of the coupler. Figure 29 also shows that same view, but as a close-up. Figure 30, however, also excludes the sprung catch 72, whereupon the hole 78 in the fixed wall 76 of the coupler can also be seen clearly. Finally, Figure 31 shows a section through the sprung catch 72 and the hole 78. This allows the spring 90, the open end, the flange 86 and the ball bearing 88 to be seen most clearly, all in their latched positions.

Instead of having the holes 80, 78 extend through the full width of the hook and the side wall of the coupler 10, they holes may be more shallow. For example, the hole 78 in the fixed wall 76 of the coupler 10 may simply be a small dimple, i.e. one suitable to fit with the ball bearing 88. The hole 80 for receiving the sprung catch 72, however, is usefully extending across the full width of the hook 32 since it allows access to the slot in the end cap 82 by a screwdriver for the above-mentioned adjustment. Nevertheless, that is not essential.

In use, the ball detent feature allows the hook 32 to be additionally latched in its latched position by the ball bearing 88 of the sprung catch 72 being retained in the hole or dimple 78 by the bias provided by the spring 90. That, therefore provides a positive retention of the hook in a latched position.

The spring bias for the ball bearing 88 may be arranged to be sufficient to provide a retention force sufficient for preventing hook movement from a latched position under mere inherent forces, such as gravity or mere jarring of the coupler. That would enable the ball detent feature to function as a latch for the hook in its own right.

It should be appreciated that the invention has been described above purely by way of example. However, modifications in detail may be made to the invention as limited purely by the claims appended hereto.

Claims

I. A coupler for attaching an accessory to an excavator arm of an excavator, the coupicr comprising a first half for connecting to the excavator arm and a second half for connecting to the accessory, the second half comprising: ajaw for receiving therein an attachment pin of the accessory; a pivoting latching device associated with the jaw; a pivot for the latching device about which the latching device is pivotable between a latched position and an unlatched position, wherein in the latched position the jaw is at least partially closed by the latching device for holding the attachment pin within the jaw; and a toggle movable between a latch back-up position and an open position, the toggle, when in its latch back-up position, serving to resist a pivoting motion of the latching device from its latched position into an unlatched position; wherein the latching device has a latch end and a non-latch end, the latch end extending away from the pivot in a first direction that extends generally towards the jaw whereby the latch end can at least partially close the jaw when the latching device is in its latched position, and the non-latch end extending away from the pivot in a second, different, direction, which direction is generally away from the jaw, the toggle serving to resist the pivoting of the latching device from its latched position into an unlatched position by having a surface that is adapted to engage against the non-latch end of the latching device.
2. The coupler of claim 1, wherein the second direction, relative to the first direction, is rotated about the pivot by an angle of between 90 and 270 .
3. The coupler of claim 1 or claim 2, wherein the non-latch end of the latching device comprises a flat bearing surface on a flange against which the surface of the toggle can bear for resisting the pivoting of the latching device from its latched position into an unlatched position.
4. The coupler of claim 3, wherein the bearing surface extends more radially than circumferentially relative to the pivot.
5. The coupler of any one of the preceding claims, wherein the latching device is a hook.
6. The coupler of any one of the preceding claims, wherein the toggle is an elongate member.
7. The coupler of any one of the preceding claims, wherein the accessory couples to the coupler by a two-point attachment, the jaw being the first one of those two points.
8. The coupler of claim 7, wherein the jaw is a first jaw and the second point is a second jaw.
9. The coupler of claim 8, wherein the second jaw faces a direction that is perpendicular to the direction of the first jaw.
10. The coupler of claim 8 or claim 9, wherein the second jaw is provided with a second latching device.
11. The coupler of any one of the preceding claims, wherein the first jaw points directly away from the first half of the coupler.
12. The coupler of any one of the preceding claims, when dependent upon claim 8, wherein the second jaw faces generally longitudinally, neither significantly towards the first half of the coupler, nor significantly towards the second half of the coupler.
13. The coupler of any one of the preceding claims, wherein the toggle is gravity operable, whereby it can disengage from its latch back-up position into an open position under the influence of gravity if the coupler is inverted such that the second half of the coupler is physically, directly and wholly above the first half of the coupler, i.e. such that the longitudinal direction of the coupler is horizontal, and can be reengaged into its blocking position by reverting the coupler to a level, upright orientation.
14. The coupler of any one of the preceding claims, wherein the toggle is a pivoting toggle mounted for rotation about a second pivot, the second pivot being spaced from the first nivot.
15. The coupler of claim 14, wherein the second pivot and the centre of gravity of the toggle are positioned relative to the non-latch end of the latching device such that the toggle is adapted to disengage from its latch back-up position, under the influence of gravity, through a range of angles of inversion by rotation about the coupler's transverse axis from a level, upright, orientation, that range of angles being from at least 350 in one direction and up to at least 90 in the other direction, the first direction being where the front end of the coupler lifts, and the other direction being where the rear end of the coupler lifts.
16. The coupler of any one of the preceding claims, wherein the latching device is biased towards its latched position by a mechanical biasing device.
17. The coupler of any one of the preceding claims, when dependent upon claim 7, wherein a mechanical biasing device for the latching device is located in a position lying generally between the two points of attachment of the coupler.
18. The coupler of claim 17, wherein the toggle is located away from the area of location of the mechanical biasing device to avoid overcrowding that area.
19. The coupler of any one of the preceding claims, wherein the toggle is positioned on a first side of, or above, the first jaw, and a mechanical biasing device for the latching device lies on a different side of that jaw to the blocking device.
20. The coupler of any one of the preceding claims, when dependent upon claim 14, wherein the second pivot is located further rearward in the coupler, and lower in the coupler, than the pivot for the latching device.
21. The coupler of any one of the preceding claims, wherein the latching device's pivot is located above and rearward of the latch end of the latching device, and positioned relative to the jaw such that the latch end has to rotate downwardly and rearwardlv in order to find a latching position.
22. The coupler of any one of the preceding claims, wherein the toggle is an elongate member that sits, in its latch back-up position, at an angle of approximately 45 upwards and forwards from its pivot relative to the longitudinal/transverse plane of the coupler.
23. The coupler of claim 22, wherein the toggle assumes a steeper angle, not exceeding 900, relative to the longitudinal/transverse plane of the coupler when it is in an open position.
24. The coupler of any one of the preceding claims, wherein the latching device has a hole in it for receiving a latch disengagement bar therein, whereby, with the latch disengagement bar, the latching device can be forced to rotate about its pivot.
25. The coupler of any one of the preceding claims, wherein at least a second surface for engaging the latching device is provided on the toggle, whereby the toggle may resist rotation of the latching device from at least two different latching positions.
26. The coupler of any one of claims 1 to 24, wherein the non-latch end of the latching device has more than one toggle bearing surface, whereby the toggle may resist rotation of the latching device from at least two different latching positions.
27. The coupler of any one of the preceding claims, wherein the toggle does not have any mechanical biasing means associated with it.
28. The coupler of any one of the preceding claims, wherein the pivoting latching device has a wall for opposing a fixed wall of the coupler when the latching device is in a latched position, those two walls featuring a sprung catch and an opposing hole, the sprung catch being adapted to engage with the hole in the other wall when the latching device is in a latched position, and wherein, upon movement of the pivoting latching device from that latched position into an unlatched position, the sprung catch is adapted to disengage from the hole.
29 The coupler of claim 2R wherein the sprung catch is in the pivoting latching device and the hole is in the fixed wall of the coupler.
30. The coupler of claim 28 or 29, wherein multiple holes are provided in one of the walls for providing multiple different positions for the sprung catch to engage with.
31. A coupler for attaching an accessory to an excavator arm of an excavator, the coupler comprising a first half for connecting to the excavator arm and a second half for connecting to the accessory, the second half comprising: a jaw for receiving therein an attachment pin of the accessory; a latching device associated with the jaw, the latching device being moveable between a latched position, in which the jaw is at least partially closed by the latching device for holding the attachment pin within the jaw, and an unlatched position, in which the attachment pin of the accessory can be removed from the jaw; wherein the latching device has a wall for opposing a fixed wall of the coupler when the latching device is in a latched position, the two walls featuring a sprung catch and an opposing hole, the sprung catch being adapted to engage with the hole in the other wall when the latching device is in a latched position, and wherein, upon movement of the latching device from that latched position into an unlatched position, the sprung catch is adapted to disengage from the hole.
32. The coupler of claim 31, wherein the catch contains a compressed coil spring, a ball bearing and a sleeve, the sleeve having a closed first end and a open second end, the second end being partially occluded by a flange.
33. The coupler of claim 31 or 32, wherein the hole is in the fixed wall of the coupler and the sprung catch is in the wall of the latching device.
34 The coupler of any one of claims 31 to 33, wherein the latching device is a pivoting latching device.
35. The coupler of any one of claims 31 to 33, wherein the latching device is a sliding latching device.
36. The coupler of any one of claims 31 to 35, wherein multiple holes are provided in the other wall for the sprung catch to engage with to define a plurality of latched positions for the latching device to allow a plurality of different accessories, each having different attachment pin spacings, to be coupled securely to the coupler.
37. A coupler substantially as hereinbefore described with reference to any one of Figures ito 17.
38. A coupler substantially as hereinbefore described with reference to any one of Figures 18 to 21.
39. A coupler substantially as hereinbefore described with reference to any one of Figures 22 to 25.
40. A coupler substantially as hereinbefore described with reference to any one of Figures26to3l.
41. A method of coupling an accessory onto an excavator arm of an excavator substantially as hereinbefore described with reference to Figures 1 to 9.
42. A method of decoupling an accessory from an excavator arm of an excavator substantially as hereinbefore described with reference to Figures 11 to 17.