WO1994024024A1

WO1994024024A1 - Loader arm assembly

Info

Publication number: WO1994024024A1
Application number: PCT/AU1994/000212
Authority: WO
Inventors: Stephen Wayne Holtom
Original assignee: Wastech Developments Pty. Limited
Priority date: 1993-04-22
Filing date: 1994-04-22
Publication date: 1994-10-27
Also published as: EP0715595A4; EP0715595A1

Abstract

A loader arm assembly (10) adapted for connection to a mobile container (14), the loader arm assembly (10) comprising a reach mechanism (11, 20, 23) operably connected to a lift mechanism (27, 31) and further adapted to accept a container retaining mechanism (32) whereby a refuse container (33) can be held by the container retaining mechanism (32), lifted by the lift mechanism, retracted towards the mobile container (14) by the reach mechanism and then the contents thereof dumped into the mobile refuse container by further operation of the lift mechanism. The assembly (10) includes systems for maintaining the level and orientation of the refuse container during rearch and lift operations.

Description

LOADER ARM ASSEMBLY TECHNICAL FIELD

The present invention relates to a loader arm assembly and, more particularly, a loader arm assembly particularly suited for picking up garbage bins from the curb side, discharging the contents into a mobile container and returning the container to the curb side. BACKGROUND ART

Loader arm assemblies for use in association with curbside garbage collection vehicles are known. For example Australian Patent No. 562,478 to Zoller-Kipper GbmH discloses a simple parallelogram link structure for hoisting a garbage bin through an arc from the curbside to adjacent a garbage collection vehicle.

New Zealand Patent Application No. 239,118 discloses a loader arm capable of significant extension from the side of a refuse collecting vehicle. The arrangement of NZ 239,118 utilises a primary arm to extend the parallelogram linkage out from the side of the vehicle.

Neither of these arrangements permits smooth, predictable, linear extension of the arm assembly to an extended position in such a way that the part of the arm assembly adapted for grabbing the curb side garbage bin moves in a level path from adjacent the mobile container to the garbage bin.

In addition to these specific problems it is also a general requirement of the industry that the loader arm assembly be capable of compact storage adjacent or within the mobile container so that it does not foul other street mounted equipment or pedestrians when the vehicle to which it is attached is in motion.

It is an object of the present invention to address or ameliorate at least some of the abovementioned disadvantages. DISCLOSURE OF INVENTION

Accordingly, in one broad form of the invention, there is provided a loader arm assembly adapted for connection to a mobile container, said loader arm assembly comprising a reach mechanism operably connected to a lift mechanism and further adapted to accept a container retaining mechanism whereby a container can be held by said container retaining mechanism, lifted by said lift mechanism, retracted towards said mobile container by said reach mechanism and the contents thereof dumped into said mobile refuse container by further operation of said lift mechanism.

Preferably said reach mechanism comprises a primary arm, a reach linkage and a secondary arm pivotally interconnected so that under the influence of a linear actuator pivotally connected to said primary arm a far end of said secondary arm is caused to traverse a shallow arc between a retracted position adjacent said mobile container and an extended position located away from said mobile container.

Preferably said primary arm is pivotally supported at a position between a near end and a far end thereof from said mobile container. Preferably said secondary arm is pivotally supported by a far end of said primary arm between and near end and a far end thereof.

Preferably a near end of said reach linkage is pivotally supported from said mobile container whilst a far end thereof is pivotally connected to said near end of said secondary arm.

Preferably the pivotal interconnection of said far end of said primary arm with said secondary arm is located at a point nearer the near end of said secondary arm than said far end of said secondary arm.

Preferably the length of said reach linkage is less than that of said primary arm.

Preferably the point of pivot interconnection of said primary arm to said mobile container is located closer to said near end of said primary arm than to said far end of said primary arm.

Preferably said lift mechanism comprises a lift arm pivotally connected by a near end thereof to said far end of said secondary arm and having a drop arm pivotally extending from a far end thereof.

Preferably said drop arm supports a container retaining mechanism.

Preferably the pivotal interconnection of said secondary arm of said reach mechanism with said lift arm of said lift mechanism subtends an angle therebetween which is controlled by a semi-rotary actuator. Preferably said far end of said lift arm, when said subtended angle is of the order of 180°, follows a substantially level path as said reach mechanism extends from a retracted position to an extended position.

In a particular preferred form said container retaining mechanism comprises a comb onto which specified refuse containers locate.

Said container retaining mechanism in an alternative preferred form comprises a grab assembly which, by means of pressure sensing fingers, changes shape to suit various kinds of refuse container.

In a further broad form of the invention there is provided a lift assembly for a refuse container or the like comprising a lift arm freely pivotally connected at a far end thereof to a drop arm.

Preferably said drop arm includes a container retainer mechanism.

Preferably said lift arm includes a rotary actuator at a near end thereof for raising and lowering the far end of said lift arm and, in consequence, said drop arm.

In a particular preferred form the loader arm assembly incorporates level maintenance means within said reach mechanism and in conjunction with said lift mechanism whereby said container retaining mechanism follows an approximately level path from adjacent said mobile container during a reach action of said reach mechanism between a fully retracted and a fully extended position thereof. Preferably said reach mechanism comprises a primary arm, a secondary arm and a reach linkage.

Preferably said reach mechanism is actuable by an actuator connected between said mobile container and said reach mechanism.

In an alternative preferred form said assembly is actuable by an actuator located at the join of said primary arm and said secondary arm.

Preferably said actuator is a rotary actuator.

In an alternative preferred form said actuator is a linear actuator having a first end pivotally connected to a pivotal join of said primary arm to said secondary arm and having its other end acting through a link which is pivotable on said primary arm, said link pivotally connected to said reach linkage.

Preferably said lift mechanism is adapted to perform a lift operation followed by a dump operation of the contents of said container.

Preferably said lift operation is performed by actuation of a first stage of a linear actuator and said dump operation is performed by actuation of a second stage of said linear actuator.

Preferably said lift operation and said dump operation are effected by a first single stage linear actuator and a second single stage linear actuator respectively.

In an alternative preferred form said lift operation and said dump operation are performed by the operation of a semi-rotary actuator or a rotary actuator; said lift operation effected by said actuator moving through a first arc of movement to a limit of movement of a first pair of limbs; said dump operation effected by movement of said actuator through a second arc of movement following on from said first arc of movement about a pivot point which is distinct from the pivot point about which said lift operation is effected.

Preferably said container retaining mechanism is suspended so as to be freely pivotable so as to maintain a predetermined orientation by the action of gravity on said assembly.

Preferably a grab comprising said container retaining mechanism is suspended freely pivotally from a drop arm.

Preferably said container retaining mechanism incorporates a projection extending from said grab adapted for engagement with a trip located on said mobile container which instigates a bin tilt and dump operation.

Preferably the assembly incorporates slave and level cylinders interconnected so as to sense the included angle between said primary arm and said secondary arm and to make corresponding levelling adjustments of the orientation of said container retaining mechanism in accordance therewith.

Preferably said container retaining mechanism is supported from a crank limb of said lift mechanism which is shaped so that said container is locatable beneath said mobile container in a fully retracted position of said reach mechanism. In a particular preferred form said assembly incorporates means to sense the degree of extension of said container retaining mechanism from said mobile container and to adjust the maximum lifting force which can be applied to said container retaining mechanism by said loader arm assembly in accordance therewith so as to limit torque exerted on said mobile container by said loader arm assembly to a safe value.

Preferably said means comprises a pressure regulator adapted to vary the maximum hydraulic pressure available to a hydraulic lift actuator to smaller values the further said container retaining mechanism is located from said mobile container. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described with reference to the drawings wherein:-

Fig. 1 is a perspective view of the loader arm assembly according to a first embodiment of the invention in an extended position attached to the side of a mobile refuse container; Fig. 2 is a side view of the assembly of Fig. 1, Fig. 3 is a top plan view of the assembly of Fig.

1, Fig. 4 is a perspective view of the assembly of

Fig. 1 in a retracted position. Fig. 5 is a perspective view of the assembly of Fig. 1 in a dump position, Fig. 6 is a top perspective view of the assembly of Fig. 1 in a dump position, Fig. 7 is a side section, time series view of the arm assembly of Fig. 1 moving from an extended position to a dump position, Fig. 8 is a side section, time series view of the arm assembly of Fig. 1 moving from a retracted position to a dump position. Fig. 9 is a side view of a loader arm assembly according to a second embodiment of the invention in an extended position, Fig. 10 is a side view of the arm of Fig. 9 in a partially retracted position. Fig. 11 is a side view of an arm assembly according to a third embodiment of the invention in an extended position, Fig. 12 is a side view of the arm of Fig. 11 in a partially retracted position, Fig. 13 is a side view of the arm of Fig. 11 in a fully retracted position, Fig. 14 is a side view of the arm of Fig. 11 in a fully retracted and partially raised position. Fig. 15 is a side view of an arm assembly according to a fourth embodiment of the invention whereby the pivot point between the primary arm and the secondary arm breaks downwardly. Fig. 16 is a side view of the arm of Fig. 15 in a partially retracted position, Fig. 17 is a side view of the arm of Fig. 15 in a fully retracted position, Fig. 18 is a side view of the arm of Fig. 15 in a fully retracted, partially raised position, Fig. 19 is a side view of the arm of Fig. 15 in a fully retracted raised position, Fig. 20 is a side view of the arm of Fig. 15 in a fully retracted dump position, Fig. 21 is a side view of an arm according to a fifth embodiment of the invention in a partially retracted position wherein the joint between the primary and secondary arms breaks downwardly and a rotary actuator is utilised for the raise operation, Fig. 22 is a side view of the arm of Fig. 21 in a dump position, Fig. 23 is a hydraulic circuit diagram for use in conjunction with a loader arm assembly of various embodiments of the invention, and Fig. 24 illustrates a pressure switch adapted to sense degree of loader arm extension for use as feedback means in the hydraulic circuit of Fig. 23, Fig. 25 is a side view of an arm assembly according to sixth embodiment of the invention in a retracted position, Fig. 26 is a side view of the arm assembly of Fig.

25 in a partially extended position, Fig. 27 is a side view of the arm assembly of Fig.

25 in an extended position with the grab assembly located around a bin, Fig. 28 is a side view of the arm assembly of Fig.

25 in an extended, bin partially raised position, Fig. 29 is a side view of the arm assembly of Fig.

25 in a retracted, partially bin raised position, Fig. 30 is a side view of the arm assembly of Fig.

25 in a retracted further raised position, Fig. 31 is a side view of the arm assembly of Fig.

25 in a retracted fully raised position, Fig. 32 is a side view of the arm assembly of Fig.

25 in a retracted, raised dump position, Fig. 33 is a side view, time series, of an arm assembly according to a seventh embodiment of the invention progressing through a reach movement. Fig. 34 is a side view of the arm assembly of Fig.

33 in a retracted, stored position, Fig. 35 is a side view of the arm assembly of Fig.

33 in a retracted, bin grabbing position, Fig. 36 is a side view of the arm assembly of Fig.

33 in a retracted partial lift position, Fig. 37 is a side view of the arm assembly of Fig.

33 in a retracted, half raised position, Fig. 38 is a side view of the arm assembly of Fig.

33 in a retracted fully raised position, Fig. 39 is a side view of the arm assembly of Fig.

33 in a retracted, fully raised trip position, Fig. 40 is a side view of an arm assembly according to an eight embodiment of the invention shown in a fully extended and a fully retracted (park) position, Fig. 41 is a side view, time series, of the arm assembly of Fig. 40 in a reach operation moving from a fully extended to a fully retracted position, Fig. 42 is a side view of the arm assembly of Fig.

40 in a retracted (park) position, Fig. 43 is a side view of the arm assembly of Fig.

40 in a retracted, bin engaging position, Fig. 44 is a side view of the arm assembly of Fig.

40 in a retracted, half raised position, Fig. 45 is a side view of the arm assembly of Fig.

40 in a retracted, fully raised position, Fig. 46 is a side view of the arm assembly of Fig.

40 in a retracted, fully raised trip position and Fig. 47 is a side view of the arm assembly of Fig. 40 in a retracted, fully raised dump position. BEST MODES FOR CARRYING OUT THE INVENTION

With reference to Fig. 1 a loader arm assembly 10 according to a first embodiment of the invention comprises, in series, a reach mechanism, a lift mechanism and a container retaining or grab mechanism.

The reach mechanism comprises a primary arm 11 pivoted at primary arm pivot point 12 about pivot pin 13. Pivot pin 13 is secured to a part of mobile refuse container 14.

The near end (that is the end nearest the mobile refuse container 14) of primary arm 11 is pivotally connected to linear reach actuator 15 at pivot point 16. The linear reach actuator 15 is mounted on the mobile refuse container 14 as well .

The ability of the reach mechanism to transport the lift mechanism (to be later described) from a retracted position adjacent the mobile refuse container 14 to an extended position away from the mobile refuse container 14 is based on the fact that the far end 18 of primary arm 11 moves from a retracted position towards an extended position as linear reach actuator 15 retracts near end 19 towards the mobile refuse container 14.

The far end 18 of primary arm 11 is pivotally connected to a secondary arm 20 at secondary arm pivot point 21.

The behaviour of far end 22 of secondary arm 20 is determined by the movement of far end 18 of primary arm 11 as controlled by reach linkage 23. The far end 24 of reach linkage 23 is pivotally connected to near end 25 of secondary arm 20. The near end 26 of reach linkage 23 is pivotally connected to the mobile refuse container 14.

The primary arm 11, the secondary arm 20 and the reach linkage 23, pivotally connected as described above, and as operated by linear reach actuator 15 form the reach mechanism.

It will be noted that the length of reach linkage 23 is only slightly less than the length of primary arm 11. The secondary arm pivot point 21 is located much closer to its near end 25 than to its far end 22. This arrangement and these dimensions allow far end 22 of secondary arm 20 to travel a shallow arcuate path in space from the retracted position to the extended position of the reach mechanism as perhaps best seen in Fig. 7.

The lift mechanism comprises a lift arm 27 which is rotatably connected at a near end 28 by a semi-rotary actuator 29 to far end 22 of secondary arm 20. The action of the semi-rotary actuator 29 is such that the far end 30 of lift arm 27 can be rotated through an arc of approximately 270° about far end 22 of secondary arm 20.

The lift mechanism is completed by a drop arm 31 which is pivotally connected to far end 30 of lift arm 27. In most circumstances this arm 31 is positioned by the action of gravity with respect to its pivotal connection with lift arm 27. The drop arm 31 supports a container retaining mechanism 32 as generally illustrated in Fig. 1. It can be seen that there are only two hydraulic power components, namely linear reach actuator 15 and semi-rotary actuator 29 forming the loader arm assembly according to a first embodiment of the invention. The container retaining mechanism 32 may or may not contain hydraulic components depending on the nature of the arrangement used to grab and release refuse container 33.

By appropriate operation of semi-rotary actuator 29 so that the angle subtended between the secondary arm 20 and the lift arm 27 is approximately 180° the path of far end 30 of lift arm 27 is smoothed to the point where it approximates a straight line (as best seen in Fig. 7). The path of the container retaining mechanism 32 is accordingly equally smoothed, thereby allowing an operator to predictably align the retaining mechanism with a container.

As also best seen in Fig. 7 the height of the container retaining mechanism 32 relative to bin 33 can be controlled by selection of the appropriate angle subtended between lift arm 27 and secondary arm 20 (as controlled by semi- rotary actuator 29).

A bin pick up and return operation usually commences with the loader arm assembly 10 in a retracted position as generally illustrated in Fig. 4.

When the vehicle approaches the refuse container, the operator simply drives the lift mechanism upwards by means of remote control joystick situated beside him in the cab. If the container is very close to the vehicle the grab fingers pass around each side of the container. If the container is a distance from the vehicle the operator simply extends the lowered grab mechanism out towards the container.

When the grab mechanism is close enough to the container, the operator depresses the grab rocker switch, situated on the top of the control joystick, and the grab fingers close around the container automatically changing shape to suit the size and shape of the object.

Once the container has been grabbed the operator drives the lift mechanism upward to lift the container clear of the ground and then retracts the reach mechanism back into the side of the leading hopper.

Once the reach arm has been fully retracted the lift arm is allowed to continue it's movement and tip the contents of the container into the compaction chamber.

Once the container is empty, the operator drives the loader down and out to the original pick-up point and releases the container, then retracts the lowered grab mechanism back to the side of the loading hopper.

The main features of this embodiment are:

1) simple construction and manufacture, thereby reducing costs.

2) low moving mass, thereby reducing shock load reactions and permitting lower strength construction techniques.

3) long reach distances can be achieved, thereby improving accessibility and production rates.

4) High range of pick-up heights due to the action of the lift mechanism, thereby improving accessibility and production rates. 5) Ease of operator use via logical arm behaviour.

Fig. 9 is a side view of a loader arm assembly according to a second embodiment of the invention in an extended position.

The loader arm assembly 210 of this second embodiment includes a primary arm 211, a secondary arm 212 and a reach linkage 213. A linear actuator 214 on plate 215 provides the motive means by which the primary arm (and hence the secondary arm via reach linkage 213) is extended away from refuse container 216 to which it is attached as illustrated in Fig. 9.

In this instance a second set of control linkages comprising first linkage 217 act to control the orientation of secondary arm 212 with respect to grab extension 219 and grab 220. Fig. 10 illustrates the manner of interaction of the components as the secondary arm 212 is retracted towards the refuse container 216.

In addition pivot linear actuator 221 permits the angle of grab 220 to be controlled. In particular grab 220 can be raised to a vertical park position when the loader arm 210 is in a fully retracted position (as illustrated in light outline in Fig. 9) .

Bin dumping is achieved through powered rotation of a rotary actuator at pivot point 222.

Fig. 10 is a side view of the arm of Fig. 9 in a partially retracted position,

Fig. 11 is a side view of an arm assembly according to a third embodiment of the invention in an extended position.

As for the first embodiment this arm assembly 310 comprises a primary arm 311, a secondary arm 312 and a reach linkage 313.

In this instance the reach motion is powered by a linear actuator 315 acting at the join, being pivot 314, between primary arm 311 and secondary arm 312. The linear actuator 315 between pivot point 314 and a pivot point 316 formed by the pivotal interconnection of links 317, 318. The other ends of links 317, 318 are pivotally connected respectively to pivot points 319, 320 at the respective ends of secondary arms 312 and primary arm 311 closest to pivot 314.

It is to be noted that link 318 continues past the point of connection to pivot 320 with its far end pivotally connected at pivot 321 to reach linkage 313 as illustrated. It is this arrangement which allows linear actuator 315 to act to change the angle of primary arm 311 with respect to refuse container 322.

In this embodiment a lift mechanism comprises an extension to secondary arm 312 comprising pivotally interconnected components limb 312A, linear actuator 312B, limb 312C and limb 312D as generally illustrated in Fig. 11.

Pivotally connected to a far end of the lift mechanism is a grab mechanism comprising pivot cylinder 323, actuation plate 324 and grab 325. Optionally the grab assembly can further include a hydraulically based grab levelling circuit which includes a slave cylinder 326 interconnected to a level cylinder 327 by hydraulic line 328. The manner in which these components act to maintain grab 325 in a level condition during a reach operation is further described with reference to hydraulic circuit diagram (Fig. 23) later in this specification.

Figs. 11 through to 14 illustrate positions of the arm assembly 310 starting from a fully extended position through to a fully retracted partly raised position.

The primary and secondary arms operate in the manner described in respect of the first embodiment to provide an essentially level path of travel for grab 325 as the included angle of the primary and secondary arms about pivot 314 varies from closed (assembly retracted) to fully open (assembly extended) . As will be appreciated the included angle of the primary and secondary arms about pivot 314 is smallest when cylinder 315 is in an extended position and is greatest when cylinder 315 is in a retracted position.

The lift mechanism comprising the extension of secondary arm 312 acts in two stages to lift the grab mechanism including grab 325 and then to move the grab mechanism over an entry chute to refuse container 322.

Firstly linear actuator 312B is extended with reference to secondary arm 312 thereby causing limb 312D to pivot about pivot 329 thereby causing the grab assembly which is attached to the far end thereof to also pivot upwardly with respect to pivot 329.

The pivoting motion about pivot 329 continues until limb 312D coextensively abuts limb 312C which causes limbs 312A, 312C and 312D to lock in the angular position illustrated in Fig. 14. During this period the length of limb 312C is fixed and forms part of a linkage which maintains the orientation of grab 325 relative to limb 312A.

Further extension of cylinder 312B causes the entire locked assembly of limbs 312A, 312C and 312D to pivot about pivot 330 thereby causing the grab assembly to move in an arc over the top of secondary arm 312 about pivot 330. Final tilt and dump of a bin held within grab 325 is effected by extension to the limit of travel of cylinder 312B causes grab 325 to further pivot about pivot 330. At this final tilted position comprising a bin emptying position is perhaps best seen in Fig. 20 (which illustrates corresponding components performing part of fourth embodiment of the invention as will now be described) .

An arm assembly according to a fourth embodiment of the invention operates essentially in the same manner and according to the same principles as have just been described in respect of the third embodiment. In this case the secondary arm is elongated with the lift mechanism freely pivoting from a far end thereof (in the manner of the first embodiment) thereby allowing the pivot point between the primary and secondary arms to break downwardly rather than upwardly during a retraction motion of the reach assembly. The linear actuator effecting the opening and closing of this join can therefore be mounted on top of the join rather than below it as for example illustrated in Fig. 15. In this fourth embodiment illustrated in Figs. 15 through to 20 corresponding components are numbered for the third embodiment so that the numbers are prefixed by a 4 (for the fourth embodiment) as opposed to a 3 (for the third embodiment). The operation is otherwise identical to that of the third embodiment and will not be described further.

In the fifth embodiment of the invention illustrated in Fig. 21 the arm assembly 510 is identical to that of the fourth embodiment save that a rotary actuator is utilized for the lift mechanism rather than corresponding linear actuator 412B to achieve lift. Once again corresponding components are labelled as for the third and fourth embodiments save that the leading digit is replaced by a 5 signifying the fifth embodiment.

In this instance a rotary actuator 532 is mounted to the end of secondary arm 512 and is pivotally connected to limbs 533, 534 as illustrated in Fig. 21. These limbs, in turn, are pivotally interconnected to crank limb 535 to a far end of which is mounted the grab assembly of the type described in respect of the third and fourth embodiments.

The principle operation to cause lift is much the same in that initial rotation of rotary actuator 532 causes limbs 533, 534 to move with respect to each other so as to cause crank limb 535 to form an acute angle therewith (refer Fig. 22). Movement of crank limb 535 with respect to limbs 533, 534 is arrested when limbs 533, 534 move to an abutting position. At this point further rotation of rotary actuator 532 causes the assembly of limbs 533, 534, 535 to rotate as a fixed pole with respect to secondary arm 512 thereby achieving a dump operation of a bin held by grab 525.

Fig. 23 illustrates a hydraulic circuit suited to control the various hydraulic actuators of the first to fifth embodiments.

The circuit comprises a hydraulic pump 40 supplying hydraulic fluid under pressure to reach hydraulic actuator 41, lift hydraulic actuator 42 and grab hydraulic actuator 43 via respective solenoid valves reach valve 44, lift valve 45 and grab valve 46.

Shuttle valves 47, 48, 49 form part of a hydraulic pressure demand circuit to allow pump 40 to deliver only the hydraulic oil which is required at the rate it is required.

Typically the solenoid valves 44, 45, 46 are actuated from controls located within the drivers cabin of a mobile refuse collection vehicle to which the arm assembly of the various embodiments is attached.

With reference to Fig. 24 a cam operated regulator can be fitted to the arm assembly in order to regulate the maximum hydraulic power available to lift actuator 42 in proportion to the extent to which the primary and secondary arms are extended from the side of the refuse collection vehicle. In this example a cam disc 47 is applied to the primary arm 11 incorporating a profile such that a plunger actuator 48 of pressure regulator valve 49 moves with respect to the regulator valve 49 in proportion to the angular orientation of primary arm 11. And the arrangement is such that as the angular orientation of primary arm 11 corresponds to the arm assembly extending further from the vehicle to which the arm assembly is mounted the pressure

» available through regulator valve 49 is decreased thereby correspondingly decreasing the maximum lifting pressure which lift actuator 42 can exert on a bin. This arrangement is designed to ensure that an operator of the arm assembly does not inadvertently cause the vehicle to which the assembly is attached to list or capsize by picking up a bin which is too heavy relative to its distance from the vehicle.

In the case of embodiments of the invention which incorporate a pivot linear actuator 221, 323, 423, 523 the pivot actuator can be connected to the hydraulic system in the manner ill-ustrated in Fig. 23 whereby a pivot action is caused to take place in sequence following a grab action and vice versa by appropriate selection of the settings of sequence valves 50, 51.

In addition optional slave actuator 326 and level actuator 327 can be utilised to maintain the level of grab 325 (refer Fig. 11 for an example of their mounting) so as to maintain grab 325 level during a reach operation thereby maintaining the grab in a horizontal position. The arrangement between the slave actuator 326 and level actuator 327 stay simple closed hydraulic circuit joined by hydraulic line 328 (but with provision for topping up from the pivot actuator circuit as illustrated in Fig. 23).

As the included angle between the primary and secondary arms closes the slave actuator 326 is compressed so as to force hydraulic oil into level actuator 327 in such a way as to counteract the tilt from level of grab 325 which would otherwise take place as the included angle between the primary and secondary arms varies.

The sixth embodiment of the invention comprising arm assembly 610 is illustrated in Figs. 25 through to 32. The primary arm 611 and secondary arm 612 are interconnected and actuated by a linear actuator 615 in the same manner as the primary arm and secondary arm of the fourth and fifth embodiments previously described. Corresponding components are numbered in like fashion prefixed with the sixth embodiment prefix 6.

As previously the interconnection of primary arm 611, secondary arm 612 and reach linkage 613 provides an arm assembly which can perform a reach movement wherein grab 625 moves level or in a shallow arc between the fully extended and fully retracted positions with respect to the truck or refuse container 622 to which the arm assembly 610 is attached as illustrated.

In this instance rotary actuators are used entirely for the lift and grab mechanisms comprising lift rotary actuator 640 and grab tilt rotary actuator 641 as for the first embodiment of the invention a drop arm 631 pivots freely from pivot 642 at the end of lift arm 627.

Whilst rotary actuators are inherently more expensive power actuation components than linear actuators the resulting arm assembly 610 contains very few components and its manner of operation is clearly evident from the side views of the arm in various positions in Figs. 25 through to 32.

Not shown in any of the figures of this embodiment is the park facility available for the grab 625. With reference to Fig. 25 grab 625 can be moved to a park position when the arm assembly 610 is in a fully retracted position by rotation of rotary actuator 641 so that grab 625 adopts a vertical position. It will be understood that in this position the arm assembly 610 does not project in any significant way from a side of the refuse container.

With reference to Figs. 33 through to 39 a seventh embodiment of the arm assembly 710 is illustrated in various positions of operation.

As for the second embodiment, a linear actuator (not shown) acts via primary arm 711 to effect a reach motion generally in the same manner and having the same characteristics as in respect of embodiments; particularly the second embodiment.

In this case the lift mechanism is achieved via a rotary actuator 732 mounted from secondary arm 712 and acting on limbs 733, 734 which in turn act on crank limb 735 in the same manner as described in respect of the fifth embodiment.

In this case the grab 725 is symmetrically, freely pivotally mounted by pivots 736 from a free end of crank limb 735 in the manner illustrated. In this case the crank limb 735 is in an elbow shape which, in the proportions selected, provides two important characteristics. Firstly when the arm assembly 710 is in a fully retracted position as illustrated in Fig. 34 the elbow causes the grab 725 to be positioned well under refuse container 722. Secondly the inside 737 of the elbow of the crank limb 735 allows a bin 738 held by grab 725 to remain freely pivoting from pivot 736 until the lift mechanism has lifted bin 738 well clear of the ground and the bin 738 is moving close to a dump position - refer Fig. 37. Only at this point does grab 725 foul inside 737 of the elbow which forces the bin 738 to move from the vertical and commence a tilt movement as rotary actuator 732 moves into its second phase of operation comprising a bin tilt operation.

With particular reference to Fig. 38 as rotary actuator 732 moves the far end of crank limb 735 through a vertical position a projection 739 on grab 725 engages with trip 740 which causes a pronounced final tilt of bin 738 as the end 741 of crank limb 735 moves beyond the vertical under the continued influence of rotary actuator 732 thereby causing the contents of bin 738 to be dumped into refuse container 722 as best illustrated in Fig. 39. It will be observed that this embodiment uses relatively few actuators and includes particular advantages of maintaining a bin 738 substantially level throughout a relatively large proportion of a reach and lift operation so as to minimise spillage.

The grab 725 can be of the type described in New Zealand patent application 239,118, but pivotally supported at pivot 736 from a position which allows the action of gravity alone to maintain the grab and consequently any bin held therein in a level condition until the high lift position illustrated in Fig. 37 and subsequently.

Figs. 40 through to 47 illustrate an eighth embodiment of an arm assembly 810.

Functionally the arm assembly 810 performs in substantially the same manner as arm assembly 710 of the seventh embodiment. In this case, however, the rotary actuator 732 is replaced by a combination of limbs and two linear actuators. Components performing the same functions as those in respect of the seventh embodiment are numbered as for the seventh embodiment except prefixed by the eighth embodiment numeral 8.

In this instance the primary arm 811 and secondary arm 812 are best adapted to be operated in conjunction with reach linkage 813 by means of a linear actuator (not shown) operating at the pivot point between the primary arm 811 and secondary arm 812 in the manner illustrated for example in the third embodiment (refer Figs. 11 and 12 in particular) . For clarity the linear actuator has not been shown in this instance.

The extension of secondary arm 812 operates according to similar principles described in respect of the secondar arm extension of the third embodiment wherein limbs 812A and 812C operate in conjunction with linear actuators 812B and 812D to effect a two stage lift operation. As best seen in Figs. 43 and 44 linear actuator 812D is utilised first to provide initial lift. When linear actuator 812D moves against limb 812C it is then necessary to bring linear actuator 812B into operation in order to cause a second phase of lift to occur about pivot 820 as best seen in Figs. 45 and 46 and 47. A trip operation takes place a described in respect of the seventh embodiment in the late stages of the dump operation.

The above describes only some embodiments of the present invention and modifications obvious to those skilled in the art can be made thereto without departing from the scope and spirit of the present invention. INDUSTRIAL APPLICABILITY

The arm assembly of various embodiments of the invention is particularly suited for mounting on mobile refuse collectors in order to provide fully automated retrieving, emptying and replacement of garbage bins located on the curbside.

Claims

1. A loader arm assembly adapted for connection to a mobile container, said loader arm assembly comprising a reach mechanism operably connected to a lift mechanism and further adapted to accept a container retaining mechanism whereby a container can be held by said container retaining mechanism, lifted by said lift mechanism, retracted towards said mobile container by said reach mechanism and the contents thereof dumped into said mobile refuse container by further operation of said lift mechanism.

2. The assembly of claim 1 wherein said reach mechanism comprises a primary arm, a reach linkage and a secondary arm pivotally interconnected so that under the influence of a linear actuator pivotally connected to said primary arm a far end of said secondary arm is caused to traverse a shallow arc between a retracted position adjacent said mobile container and an extended position located away from said mobile container.

3. The assembly of claim 1 wherein said primary arm is pivotally supported at a position between a near end and a far end thereof from said mobile container.

4. The assembly of claim 1 wherein said secondary arm is pivotally supported by a far end of said primary arm between a near end and a far end thereof.

5. The assembly of claim 4 wherein a near end of said reach linkage is pivotally supported from said mobile container whilst a far end thereof is pivotally connected to said near end of said secondary arm.

6. The assembly of claim 5 wherein the pivotal interconnection of said far end of said primary arm with said secondary arm is located at a point nearer the near end of said secondary arm than said far end of said secondary arm.

7. The assembly of claim 6 wherein the length of said reach linkage is less than that of said primary arm.

8. The assembly of claim 7 wherein the point of pivot interconnection of said primary arm to said mobile container is located closer to said near end of said primary arm than to said far end of said primary arm.

9. The assembly of claim 8 wherein said lift mechanism comprises a lift arm pivotally connected by a near end thereof to said far end of said secondary arm and having a drop arm pivotally extending from a far end thereof.

10. The assembly of claim 9 wherein said drop arm supports a container retaining mechanism.

11. The assembly of claim 10 wherein the pivotal interconnection of said secondary arm of said reach mechanism with said lift arm of said lift mechanism subtends an angle therebetween which is controlled by a semi-rotary actuator.

12. The assembly of claim 11 wherein said far end of said lift arm, when said subtended angle is of the order of 180°, follows a substantially level path as said reach mechanism extends from a retracted position to an extended position.

13. The assembly of claim 1 wherein said container retaining mechanism comprises a comb onto which specified refuse containers locate.

14. The assembly of claim 1 wherein said retainer container mechanism comprises a grab assembly which, by means of pressure sensing fingers, changes shape to suit various kinds of refuse container.

15. The assembly of claim 1 wherein said lift arm includes a rotary actuator at a near end thereof for raising and lowering the far end of said lift arm and, in consequence, said drop arm.

16. The loader arm assembly of claim 1 incorporating level maintenance means within said reach mechanism and in conjunction with said lift mechanism whereby said container retaining mechanism follows an approximately level path from adjacent said mobile container during a reach action of said reach mechanism between a fully retracted and a fully extended position thereof.

17. The assembly of claim 16 wherein said reach mechanism comprises a primary arm, a secondary arm and a reach linkage.

18. The assembly of claim 17 wherein said reach mechanism is actuable by an actuator connected between said mobile container and said reach mechanism.

19. The assembly of claim 17 actuable by an actuator located at the join of said primary arm and said secondary arm.

20. The assembly of claim 19 wherein said actuator is a rotary actuator.

21. The assembly of claim 19 wherein said actuator is a linear actuator having a first end pivotally connected to a pivotal join of said primary arm to said secondary arm and having its other end acting through a link which is pivotable on said primary arm, said link pivotally connected to said reach linkage.

22. The assembly of claim 1 wherein said lift mechanism is adapted to perform a lift operation followed by a dump operation of the contents of said container.

23. The assembly of claim 22 wherein said lift operation is performed by actuation of a first stage of a linear actuator and said dump operation is performed by actuation of a second stage of said linear actuator.

24. The assembly of claim 22 wherein said lift operation and said dump operation are effected by a first single stage linear actuator and a second single stage linear actuator respectively.

25. The assembly of claim 22 wherein said lift operation and said dump operation are performed by the operation of a semi-rotary actuator or a rotary actuator; said lift operation effected by said actuator moving through a first arc of movement to a limit of movement of a first pair of limbs; said dump operation effected by movement of said actuator through a second arc of movement following on from said first arc of movement about a pivot point which is distinct from the pivot point about which said lift operation is effected.

26. The assembly of claim 1 wherein said container retaining mechanism is suspended so as to be freely pivotable so as to maintain a predetermined orientation by the action of gravity on said assembly.

27. The assembly of claim 26 wherein a grab comprising said container retaining mechanism is suspended freely pivotally from a drop arm.

28. The assembly of claim 26 wherein said container retaining mechanism incorporates a projection extending from said grab adapted for engagement with a trip located on said mobile container which instigates a bin tilt and dump operation.

29. The assembly of claim 26 incorporating slave and level cylinders interconnected so as to sense the included angle between said primary arm and said secondary arm and to make corresponding levelling adjustments of the orientation of said container retaining mechanism in accordance therewith.

30. The assembly of claim 1 wherein said container retaining mechanism is supported from a crank limb of said lift mechanism which is shaped so that said container is locatable beneath said mobile container in a fully retracted position of said reach mechanism.

31. The assembly of claim 1 incorporating means to sense the degree of extension of said container retaining mechanism from said mobile container and to adjust the maximum lifting force which can be applied to said container retaining mechanism by said loader arm assembly in accordance therewith so as to limit torque exerted on said mobile container by said loader arm assembly to a safe value.

32. The assembly of claim 31 wherein said means comprises a pressure regulator adapted to vary the maximum hydraulic pressure available to a hydraulic lift actuator to smaller values the further said container retaining mechanism is located from said mobile container.