EP0757656A4

EP0757656A4 - Compaction assembly

Info

Publication number: EP0757656A4
Application number: EP94913454A
Authority: EP
Inventors: Stephen Wayne Holtom
Original assignee: Wastech Developments Pty Ltd
Current assignee: Wastech Developments Pty Ltd
Priority date: 1993-04-22
Filing date: 1994-04-22
Publication date: 1997-05-07
Also published as: WO1994024025A1; EP0757656A1

Abstract

A compaction assembly (10) for use in conjunction with a guide (11) whereby refuse material and the like is urged along the guide (11) into a container (12) and compacted into the container (12); the compaction assembly (10) comprising primary motive means (31) adapted to drive the working face (16, 17) of a paddle (15) along the guide (11); the compaction assembly further including secondary motive means (19) adapted to provide additional motive power to the working face (16, 17) of the paddle during its traverse through at least a portion of its travel. The arrangement broadly provides a system for matching available power from a power source to required power of one or more cyclic power consuming components over at least most of their operating cycles most of the time; the system includes at least two power consuming components acting to achieve a common task; one of the components (31) is rated to deliver low power over an entire operational cycle; the other of the components (19) is adapted to deliver higher power but over only a portion of the operational cycle whereby maximum power demand for the entire system can be limited by controlling when the other component (19) comes into operation and the speed at which the other component (19) operates.

Description

COMPACTION ASSEMBLY TECHNICAL FIELD

The present invention relates to a compaction assembly and, more particularly, to such an assembly particularly suited for refuse compaction. BACKGROUND ART

In order to make the most efficient use of the volume of a mobile refuse container, it is usual for the container to include some form of compacting ram arrangement which performs the dual function of urging refuse material from a loading section into an inlet of the refuse container and also of compacting the refuse within the container.

The power to weight ratios of prior art devices are reasonable but the market continues to require improvements in this regard.

A further problem of the prior art is that mobile refuse containers now typically incorporate other power drawing equipment such as loading arms. The total power requirement for all of the equipment can be quite large to the extent that not all power drawing equipment can be operated at the one time.

An ancilliary problem is that as total power draw increases, typically the noise of the equipment increases as well. It is no longer acceptable in many societies for noise levels of mobile refuse containers and the like to exceed predetermined levels. DISCLOSURE OF INVENTION

It is an object of the present invention to address this market requirement, particularly where the amount of power available to the compaction assembly either is limited or it is desired that it be limited.

According to one aspect of the invention there is provided a compaction assembly for use in conjunction with a guide whereby refuse material and the like is urged along said guide into a container and compacted into said container; said compaction assembly comprising primary motive means adapted to drive the working face of a compactor blade along said guide; said compaction assembly further including secondary motive means adapted to provide additional motive power to said working face of said blade during its traverse through at least a portion of its travel. The secondary motive means may comprise a linear actuating ram.

The primary and secondary motive means may be hydraulically activated.

The primary motive means may comprise a source of rotary mechanical movement.

According to a further aspect of the invention there is provided a mechanism for providing an order of magnitude variation in torque exerted by a hydraulic system on a shaft at approximately constant hydraulic pressure comprising a rotary or semi-rotary actuator adapted to provide a base torque to said shaft combined with a linear actuator acting through a mechanical linkage upon said shaft adapted to provide a much higher torque than said base torque, but at reduced rotational velocity of said shaft such that hydraulic fluid pressure requirements of a common hydraulic fluid supply to both said hydraulic motor and said linear actuator are approximately the same. In a further broad form of the invention there is provided a mechanism which^'provides an order of magnitude variation in torque exerted by a hydraulic system on a shaft comprising a rotary or semi-rotary actuator adapted to provide a base torque to said shaft combined with a linear actuator acting through a mechanical linkage upon said shaft adapted to provide a much higher torque than said base torque.

Preferably said mechanism is utilised to operate a compaction assembly. Preferably said mechanism further includes a loader arm acutated by hydraulic means which is fed from the same source of hydraulic pressure as said mechanism.

In yet a further broad form of the invention there is provided a system for matching available power from a power source to required power of one or more cyclic power consuming components over at least most of their operating cycles most of the time; said sytem comprising including at least two power consuming components acting to achieve a common task; one of said components rated to deliver low power over an entire operational cycle; the other of said components adapted to deliver higher power but over only a portion of the operational cycle; whereby maximum power demand for the entire system can be limited by controlling when said other component comes into operation and the speed at which said other component operates.

Preferably said one component comprises a rotary or semi-rotary actuator. Preferably said other component comprises a linear actuator.

Preferably said system is applied to a mobile refuse vehicle which includes a compaction assembly operable by said at least two power consuming components together with a loader arm incorporating reach, lift and grab capabilities.

In yet a further broad form of the invention there is provided a system for reduction of overall power demand for a compaction assembly; said system including inclining upwardly the guide in which the working face of a compactor operates such that material urged by said working face is directed at an upwardly inclined angle into a container. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which : - Fig. 1 is a perspective view of a compaction assembly associated with a guide attached to a refuse container according to a first embodiment of the invention,

Fig. 2 is a side view of an entire truck mounted refuse container incorporating the compaction assembly and guide of Fig. 1 inclined so as to direct refuse upwardly into the refuse container, Fig. 3 is a side view of the compaction assembly of Fig. 2 with the guide cut away, Fig. 4 is a plan view of the compaction assembly of Fig. 3 showing its paddle in three different working positions, Fig. 5 is a hydraulic schematic diagram for the compaction assembly of either Fig. 1 or Fig. 2,

Fig. 6 is a perspective view of a compaction assembly attached to a refuse container according to a second embodiment of the invention, and Fig. 7 is a hydraulic schmatic circuit for a loader arm for use in conjunction with the hydraulic circuit of Fig. 5 and sharing a common source of hydraulic power. BEST MODES FOR CARRYING OUT THE INVENTION In Figure 1 there is shown a compaction assembly 10 according to a first embodiment of the invention associate with a guide in the form of a bowl 11 attached to a rear end of a storage volume 12 wherein refuse or like material can be urged from the guide bowl 11 into the interior of the storage volume 12 by means of a paddle assembly 13.

The paddle assembly 13 comprises a shaft 14 rotatably driven by a hydraulic motor (not shown) a paddle 15 including first working face 16 and second working face 17 extends perpenicularly from an end of the shaft 14.

In use shaft 14 is rotated by the hydraulic motor (not shown) in the form of a rotary or semi-rotary actuator constituting a primary motive means whereby either first working face 16 (if the shaft is rotated anti-clockwise) or second working face 17 (if the shaft is rotated clockwise) is caused to urge refuse or the like in the direction of and thence through aperture 18 of storage volume 12 whereby the refuse is compacted into storage volume 12. The rotational direction of shaft 14 is then reversed whereby paddle 15 returns to its rest position as generally shown in Fig. 1.

The compaction assembly 10 additionally includes a liner hydraulic actuator 19 having one end connected to bowl 11 and the other end connected to a stub 20 which extends generally perpendicularly from shaft 14 as illustrated in Fig. 1.

The linear hydraulic actuator 19 is adapted to exert a torque upon shaft 14 via stub 20, which torque can be used to supplement the torque exerted on shaft 14 by the hydraulic motor (not shown) .

The arrangement is such that the supplementary torque is exerted in that part of the working cycle of paddle assembly 13 where the load required to be exerted by the working faces 16, 17 is the greatest. This will usually be as the working faces 16, 17 approach and pass through aperture 18.

The torque which can be exerted by actuator 19 is significantly greater than that which can be exerted by t hydraulic motor. This matches with the torque requiremen experienced by the semi-rotary actuator during use in tha for the majority of its cycle, only a relatively low torq is required to move the actuator. In the relatively shor part of the cycle where very high compaction forces are required to be exerted, the linear hydraulic actuator 19 sized to exert the required torque.

In this manner, on average, lower hydraulic oil flow and pressure is required to operate the unit eg. 10 litre per minute and 200 bar pressure which equates to a power requirement of 4 kW to produce a six second cycle and 15 tonnes of compaction force.

The linear hydraulic actuator 19 can be brought into operation by two means. According to a first means actua torque required for shaft 14 to rotate is sensed (either directly or via hydraulic oil fluid pressure) and when th sensing arrangement indicates that higher pressure (ie. torque) is required then the linear hydraulic actuator 19 is energised by way of a solenoid valve directing hydraul fluid to the actuator.

An alternative means simply requires a limit switch t sense when, for example, stubb 20 has reached an angular position which, in normal use, will correspond to a high torque requirement for shaft 14. The limit switch operat a solenoid valve which, in turn, directs hydraulic fluid linear hydraulic actuator 19 so that the additional torqu provided by that actuator can be exerted upon shaft 14. Once the high power actuator has driven the paddle to the required position, it returns to the idle mode and the paddle reverses rotation.

Some of the advantages of this embodiment of the invention are as follows.*-

(i) low flow requirement, thereby reducing power demand, (ii) low mass, thereby increasing mass/load ratio of compactor, (ϋi) simple construction, thereby reducing cost of manufacture, and Fig. 2 illustrates the compaction assembly 10 of Fig. 1 and storage volume 12 mounted on a truck chassis 30. Like components are numbered as for Fig. 1. In this instance the compaction assembly 10 including bowl 11 is mounted so as to be inclined with respect to the storage volume 12 such that refuse urged by a working face of paddle 15 through aperture 18 is urged in an upwardly inclined direction into the interior of storage volume 12. This arrangement also permits aperture 18 to be located higher up the storage volume 12 with the attendant advantage that refuse material within storage volume 12 will only block aperture 18 when storage volume 12 is significantly filled with refuse. Fig. 3 illustrates the inclined compaction assembly and bowl of Fig. 2 in greater detail.

In Fig. 3 the semi-rotary actuator 31 comprising the primary motive means for paddle assembly 13 is shown as in mounted aligned with the line of actuation of linear hydraulic actuator 19.

Fig. 4 illustrates the compaction assembly 10 with paddle assembly 13 in both a home position with linear actuator 19 retracted and in symmetrical positions requiring high urging force where linear actuator 19 is extended and operates to urge stubb 20 so as to apply additional torque to shaft 14.

Fig. 5 is a hydraulic schematic diagram illustrating the logic and hydraulic oil flow by which both semi-rotary actuator 31 and linear hydraulic actuator 19 are driven.

Linear actuator 19 is forcibly driven by hydraulic oil pressure only when pressure switch 32 senses that hydrauli pressure requirements are above a predetermined pressure (correlating to a load on paddle 15 above that which can b handled by semi-rotary actuator 31 alone) .

In normal low pressure demand operation hydraulic flui from source P passes through valve assembly 34 following actuation of a solenoid connected to an operator control i the cab of truck chassis 30 whereby semi-rotary actuator 3 is caused to rotate from a home position as sensed by proximity switch PI to a paddle extended position as sense by proximity switch P2.

Linear hydraulic actuator 19 simply "free wheels" recirculating hydraulic oil through cartridges 35, 36. However should pressure switch 32 sense a large hydraulic load above a predetermined level then pilot valv 37 on cartridge 36 is operated to close the cartridge causing hydraulic oil to bypass through check valve 38 int chamber 33 of linear actuator 19. Linear actuator 19 thereby provides a power assist stroke to the rotation of semi-rotary actuator 31 via stub 20. Shuttle valves 39, 40 provide a load sensing recirculation system whereby oil provided at a high flow rate (for example 200 litres per minute from source P) is diverted so that an oil supply at a much lower rate, for example, 4 litres per minute, is supplied to the actuators In Figure 6 there is shown a second embodiment of the compaction assembly 21 in which the axis of the assembly runs generally across the width of the aperture 22 through which refuse is to be urged into storage volume 23.

The primary motive means is provided by a hydraulic motor 24 which urges paddle 25 in the direction of apertur 22 by rotatably urging connecting rod 26 via stub connectors 27.

As paddle 25 approaches closely to aperture 22 where a relatively large force is required in order to compact refuse as it passes through aperture 22, then hydraulic linear actuators 28, 29 are brought into operation. These actuators each have one end connected to storage volume 23 with their other ends rotatably connected to connecting ro 26 as illustrated in Fig. 6. By this means the large forces required over only a small part of the working cycle of the load responsive compaction assembly according to a second embodiment can b provided. As for the first embodiment the time when and -l i ¬

the duration over which the actuators 28, 29 are to be activated can be determined either by direct load sensing or via position sensing.

According to a third embodiment of the invention a control system is provided which allows matching of the hydraulic pressure requirements of competing hydraulic loads.

For example the compaction assembly previously described may be utilised, in conjunction with a hydraulically actuated loader arm on a refuse collection vehicle. In this situation it is desirable that hydraulic fluid pressure supplied to both the loader arm hydraulics and to the compaction assembly hydraulics be of the same order of magnitude. This can be achieved by matching the operational hydraulic fluid pressure requirement of the loader arm to the hydraulic fluid pressure requirement of the primary motive means of the compaction assembly. This is specifically achieved by appropriate selection of the parameters of the hydraulic motor of the compaction assembly, sized for refuse movement duty (but not refuse compaction duty) .

With this arrangement the secondary motive means comprising linear hydraulic actuator 19, 28, 29 is adapted to provide increased linear force at reduced speed for the same (or approximately the same) hydraulic fluid pressure. In this way relatively stable hydraulic fluid pressure requirements can be maintained in the system whilst providing the capability for increasing the force to be applied to refuse (when compaction is taking place) by up to 30 times the base force requirements.

For efficient operation of the hydraulic system within these parameters it is desirable that both position sensing and hydraulic pressure sensing be utilised in order to determine when to bring the secondary motive means into operation. That is, the control logic required is that the secondary motive means comes into operation only when the compaction assembly is in a position where it is expected that high compaction force will be required (position sensing) and sensing of hydraulic pressure indicates that a heavy load indicative of compaction is actually being experienced (pressure sensing) . Fig. 7 illustrates a hydraulic diagram for hydraulic actuators associated with a refuse container lifting and dumping arm incorporating reach, lift and grab capabilities. This circuit can be supplied from the same hydraulic oil source P that supplies the compaction assembly 13 due to the relatively constant and relatively low oil flow and oil pressure requirements of the compaction assembly 13 throughout most of its operational cycle during most cycles.

The hydraulic circuit of Fig. 7 is suitable for hydraulic actuation of refuse loader arms of the type, for example, to be found in NZ Patent Application No. 239,118 (assigned to the present applicant) . Such loader arm assemblies are often of significant size and draw significant amounts of hydraulic power accordingly. For example hydraulic oil requirements for a reach operation can be of the order of 15 litres per minute at 1,500 to 2,000 psi. Lift operations can require of the order of 40 litres per minute at 1,500 to 2,000 psi. Grab operations can require 10 litres per minute at 1,500 to 2,000 psi. These oil requirements equate typically to an engine horsepower draw on the mobile vehicle of the order of 20 horsepower. Ideally it is preferred that this power draw be available when the engine is idling. Typically diesel engines can provide this power at idle speeds of the order of 700 rpm. However this leaves little power over to operate other hydraulic equipment such as, for example, compaction assemblies of the type disclosed in the present application.

In terms of priority of operation it is desirable that the loader arm assembly never be power limited otherwise this can lead to delays in picking up and replacing garbag bins on the side of the road. Equally it is desirable tha the compaction assembly not be required to cease operation altogether for lack of available power. However reduction in operating speed is acceptable although it is preferred that such reductions in operational speed be restricted to only portions of the compaction assembly operational cycle (for example only when very high power is required for compaction as opposed to mere urging of refuse across a surface) . The compaction assembly 10 of the first embodiment operated by the hydraulic circuit of Fig. 5 combined with loader arm assembly having reach, lift and grab facilities operated by a hydraulic circuit of the type illustrated in Fig. 7 can achieve this desired result.

With reference to Fig. 7 a hydraulic pump 41 supplies hydraulic oil through restrictor 32 to three solenoid valv assemblies, a reach solenoid valve assembly 43, a lift solenoid valve assembly 44 and a grab solenoid valve assembly 45. The solenoid valves 43, 44, 45 are operated via operator controls located in the cab of the mobile refuse vehicle so as to achieve grabbing, lifting and dumping of refuse containers and, where appropriate, reaching in order to grab refuse containers. In addition, hydraulic line 46 supplies hydraulic flui to source P of the compaction assembly hydraulic circuit illustrated in Fig. 5. Finally, a load sensing circuit comprising shuttle valves 39, 40 from the compaction assembly circuit together with shuttle valves 47, 48, 49 from the loader arm hydraulic circuit of Fig. 7 provide a hydraulic fluid flow feedback signal to pump 41 to ensure that pump 41 supplies hydraulic fluid at the rate required by the various hydraulic components making up the complete hydraulic circuit. The nominal design flow requirement for hydraulic line

46 is 4 litres per minute of hydraulic fluid at a pressure of 1,500 to 2,000 psi and which is sufficient to operate semi-rotary actuator 31 at normal speed throughout its entire operational cycle - unless the compaction assembly encounters a high compaction load as indicated by hydraulic pressure rising to above 2,500 psi and as sensed by pressure switch 32 (Fig. 5). At this point solenoid valve 48 is activated by pressure switch 32 causing pilot valve 37 to operate to allow hydraulic fluid to be pumped into chamber 33 of linear hydraulic actuator 19. If the loader arm assembly is working and is drawing significant amounts of hydraulic power then hydraulic fluid flow along hydraulic line 46 can be limited to 4 litres per minute in which case linear actuator 19 will operate but at reduced speed. If the loader arm is not consuming any significant amount of hydraulic power then the flow rate along line 46 can be increased in order to allow linear actuator 19 to move more quickly. In this particular instance a typical maximum design fluid flow rate would be of the order of 40 litres per minute at around 2 , 500 psi corresponding to a power draw from hydraulic pump 41 of the order of 20 horsepower. It will be appreciated that the design of the combined circuits of Fig. 5 and 7 is such that maximum power draw from pump 41 can be limited to the order of 20 horsepower without significantly affecting the operation of either the loader arm or the compaction assembly, other than that the operation of linear hydraulic actuator 19 is slowed (but not stopped) during periods of high power requirement from the loader circuit. This low speed limitation on linear actuator 19 is likely to occur relatively rarely throughout many operating cycles of the refuse vehicle as the condition is likely to arise only when a significant amount of refuse is already located within the container of the vehicle necessitating high compaction forces to be applied at a time when the loader arm is also operational .

It will further be appreciated that the entire assembly can remain operational with the refuse vehicle's engine operating at idle speed - revving of the engine will not be necessary and will not cause a significant change in operating behaviour of either the loader arm or compaction assembly in any event .

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.

For example the primary motive means can comprise almost any form of actuator. Similarly the secondary motive means can comprise almost any form of actuator. The overall requirement is that the secondary motive means is adapted to supply a greater amount of power than the primary motive means but over a more limited part of an operational cycle of the compaction assembly. INDUSTRIAL APPLICABILITY

The compaction assembly arrangement of the invention is particularly useful with bulk mobile refuse handling facilities. It has particular application in systems where available power to drive power consuming components is limited.

Claims

1. A compaction assembly for use in conjunction with a guide whereby refuse material and the like is urged along said guide into a container and compacted into said container; said compaction assembly comprising primary motive means adapted to drive the working face of a compactor along said guide; said compaction assembly further including secondary motive means adapted to provide additional motive power to said working face of said compactor during its traverse through at least a portion of its travel.

2. A compaction assembly according to claim 1 wherein said primary motive means comprises a source of rotary mechanical movement.

3. A compaction assembly according to claim 1 or claim 2 wherein said secondary motive means comprises a linear actuating arm.

4. A compaction assembly according to any one of the preceding claims wherein both said primary and said secondary motive means are hydraulically activated.

5. A mechanism for providing an order of magnitude variation in torque exerted by a hydraulic system on a shaft comprising a rotary or semi-rotary actuator adapted to provide a base torque to said shaft combined with a linear actuator acting through a mechanical linkage upon said shaft adapted to provide a much higher torque than said base torque. 6. The mechanism of claim 5 utilised to operate a compaction assembly.

7. The mechanism of claim 6 further including a loader ar acutated by hydraulic means which is fed from the same source of hydraulic pressure as said mechanism.

8. A system for matching available power from a power source to required power of one or more cyclic power consuming components over at least most of their operating cycles most of the time; said system including at least tw power consuming components acting to achieve a common task; one of said components rated to deliver low power over an entire operational cycle; the other of said components adapted to deliver higher power but over only a portion of the operational cycle; whereby maximum power demand for th entire system can be limited by controlling when said othe component comes into operation and the speed at which said other component operates.

9. The system of claim 8 wherein said one component comprises a rotary or semi-rotary actuator.

10. The system of claim 8 wherein said other component comprises a linear actuator.

11. The system of claim 8 applied to a mobile refuse vehicle which includes a compaction assembly operable by said at least two power consuming components together with a loader arm incorporating reach, lift and grab capabilities. 12. A system for reduction of overall power demand for a compaction assembly; said system including inclining upwardly the guide in which the working face of a compactor operates such that material urged by said working face is directed at an upwardly inclined angle into a container.

13. The system of claim 12 applied to a side-load or front- load container.

14. The system of claim 12 wherein said guide guides said material into an aperture located at mid height within the volume of the container.