The present invention relates to a pump and to a waste disposal truck. The invention also relates to a method for pumping a pumpable material into a pumpable material storage chamber of a waste disposal truck.

Waste disposal trucks are well known, and are typically used for collecting domestic waste material, and transporting the waste material to a suitable waste material disposal site, which may be a waste material disposal plant, an incinerator, or a landfill site. Typically, domestic waste for collection by a waste disposal truck is stored in a suitable bin, and on specific collection days, the bin along with other bins is placed on the footpath in a housing estate, or on a main road. A waste disposal truck is driven along the road or through the estate, and the domestic waste in the bins is sequentially emptied from the bins into the waste disposal truck. Typically, such waste disposal trucks comprise a solid matter storage chamber and a compactor, which is generally located rearwardly of the solid matter storage chamber for compacting the domestic waste prior to being transferred into the solid matter storage chamber. A lifting mechanism, in general, is located to the rear of the compactor for lifting and tipping a bin for discharging the domestic waste therein into the compactor. The compactor then compacts and transfers the domestic waste into the solid matter storage chamber.

With the ever increasing amount of domestic waste, and the environmental damage which results from disposal of domestic waste, householders are being urged to separate domestic waste into a number of categories in order to facilitate segregated waste collection. These categories include; recyclable materials for example cardboard, paper, plastic, glass, and the like; non-recyclable residual waste, for example, nappies, contaminated packaging, and other such non-recyclable waste; biodegradable garden waste, for example, yard trimmings, grass, leaves, and the like; and biodegradable household food and kitchen waste, for example, meat, eggs, dairy products, bread, fruit and vegetable waste. Such biodegradable household food and kitchen waste may comprise waste material resulting from food

preparation, such as fruit and vegetable skins, and other food which has deteriorated to a state where it becomes unusable. This biodegradable household food and kitchen waste has a relatively high moisture content, and due to its relatively high moisture content, in general, is of a pumpable consistency. On the more recent generation of waste disposal trucks a separate chamber for storing such pumpable material is provided. The pumpable material storage chamber may be located on the waste disposal truck above the solid matter storage chamber, or may be located on the bed of the truck between a driver's cab of the truck and the solid matter storage chamber. However, irrespective of the location of the pumpable material storage chamber, it is essential that the pumpable material be pumped into the pumpable material storage chamber. This, in general, requires mounting a pump on the waste disposal truck, which typically is located adjacent a side or to the rear of the truck. Such pumps, in general, suffer from a number of disadvantages, in that firstly, they tend to be unsuitable for pumping such domestic pumpable material, and secondly, in general, due to the nature of such pumps, pumpable waste material cannot be conveniently manually delivered into such pumps from a bin or other such container, for example, a bucket.

There is therefore a need for a pump which addresses at least some of the problems of prior art pumps. There is also a need for a waste disposal truck which addresses some of the problems of known waste disposal trucks. Further, there is a need for a method for pumping a pumpable material into a pumpable material storage chamber of a waste disposal truck.

The present invention is directed towards providing a pump. The invention is also directed towards providing a waste disposal truck, and further, the invention is directed towards providing a method for pumping a pumpable material into a pumpable material storage chamber of a waste disposal truck.

According to the invention there is provided a pump for pumping a pumpable material, the pump comprising a pump housing defining a pump chamber having an outlet port therefrom, a piston, one of the piston and the pump housing being moveable relative to the other one of the piston and the pump housing for sweeping the piston from a first state to a second state through the pump chamber for displacing pumpable material from the pump chamber through the outlet port therefrom, and an inlet port to the pump chamber for accommodating delivery of the pumpable material into the pump chamber, the inlet port being located intermediate the location of the piston in the first state and the location of the piston in the second state. Preferably, the inlet port is located closer to the location of the piston in the first state than to the location of the piston in the second state. Advantageously, the inlet port is located downstream from the location of the piston in the first state thereof.

In one aspect of the invention the inlet port is defined by the pump housing.

Preferably, the pump chamber comprises an elongated pump chamber.

Advantageously, the piston is swept longitudinally through the pump chamber.

In another aspect of the invention the piston is configured to be located externally of the pump chamber in the first state.

In another aspect of the invention the pump chamber defines an upstream end and a downstream end, and the piston is swept through the pump chamber from the upstream end to the downstream end for displacing the pumpable material through the outlet port. Preferably, the outlet port is located adjacent the downstream end of the pump chamber.

In another aspect of the invention the pump chamber terminates at the upstream end thereof in an open mouth. Preferably, the open mouth in which the pump chamber terminates at its upstream end faces in a direction towards the location of the piston in the first state.

In a further aspect of the invention the location of the piston in its first state is spaced apart from the open mouth in which the pump chamber terminates at its upstream end.

Preferably, the open mouth in which the pump chamber terminates is defined by the pump housing.

In one aspect of the invention the open mouth defines the inlet port.

Preferably, the piston is configured so that when the moveable one of the piston and the pump housing is moved relative to the other for urging the piston relative to the pump housing from the first state to the second state, the piston is urged into the pump chamber through the inlet port.

In one aspect of the invention the pump housing comprises a peripheral wall defining the pump chamber. Preferably, the inlet port is defined by the peripheral wall of the pump housing. Advantageously, the inlet port is defined by an upper edge of the peripheral wall of the pump housing.

Alternatively, the inlet port is defined between the pump housing and the piston when the piston is in the first state.

In another aspect of the invention a guide means is provided for guiding the piston from the first state into the pump chamber. Preferably, the guide means is configured to guide the piston from the first state through the inlet port into the pump chamber.

In another aspect of the invention the piston is resiliently urged into engagement with the guide means. Preferably, a resilient urging means is provided for urging the piston into engagement with the guide means.

In another aspect of the invention a chute is provided extending from the pump housing adjacent the inlet port for receiving and directing pumpable material into the pump chamber. Preferably, the chute is configured for directing pumpable material into the pump chamber through the inlet port. Advantageously, the chute is urgeable from a receiving state for receiving and directing pumpable material into the pump chamber, and a guide state co-operating with the piston for guiding the piston from the first state into the pump chamber.

In another aspect of the invention a drive means is provided for urging the piston from the first state to the second state.

Preferably, an anchorage is provided, and the drive means is operably connected between the anchorage and the moveable one of the piston and the pump housing.

In another aspect of the invention a sub-housing is provided extending from the pump housing. Preferably, the sub-housing extends from the pump housing adjacent the inlet port.

In another aspect of the invention the sub-housing defines an inlet opening, and the inlet opening communicates with the inlet port through the sub-housing. Preferably, the inlet opening is located in the sub-housing between the inlet port and the location of the piston in the first state.

Advantageously, the anchorage is formed in the sub-housing. Preferably, the drive means is located in the sub-housing.

Advantageously, the piston is located in the sub-housing in the first state.

In another aspect of the invention a disabling means is provided for preventing the drive means urging the piston from the first state to the second state until the chute is in the guide state. In one aspect of the invention the pump housing is configured so that the pump chamber extends substantially vertically in use, with the upstream end of the pump chamber located above the downstream end of the pump chamber. Preferably, the pump chamber is defined by an elongated bore extending through the pump housing. Advantageously, the bore extending through the pump chamber is closed at the downstream end thereof by an end cap. Ideally, the pump chamber is of circular transverse cross-section.

In another aspect of the invention the pump is configured for pumping food waste.

The invention also provides a waste disposal truck comprising a pumpable material storage chamber, and the pump according to the invention for pumping pumpable material into the pumpable material storage chamber.

Additionally the invention provides a waste disposal truck comprising a pumpable material storage chamber, and a pump for pumping the pumpable material into the pumpable material storage chamber.

In one aspect of the invention the pump is located at a level on the truck whereby a person carrying a container of pumpable material can discharge the pumpable material from the container into the pump chamber by manually tipping the container for discharging the pumpable material into the pump chamber.

In a further aspect of the invention the pump comprises an inlet port, and the pump is mounted on the truck with the inlet port at a level for receiving pumpable material from a container held by a person and manually tipped by the person for discharging the pumpable material from the container.

In one aspect of the invention the pump is mounted on the truck with the inlet port at a level above the ground not exceeding 1,500mm. Preferably, the pump is mounted on the truck with the inlet port located at a level above the ground lying in the range of 900mm to 1 ,500mm. Advantageously, the pump is mounted on the truck with the inlet port located at a level above the ground lying in the range of 1 ,000mm to 1 ,200mm. Ideally, the pump is mounted on the truck with the inlet port at a level above the ground of approximately 1 ,100mm. In another aspect of the invention a chute is provided from the pump for directing pumpable material into the pumping chamber through the inlet port, the pump being mounted on the truck with the chute at a level for receiving pumpable material from a container carried by a person and manually tipped by the person for discharging the pumpable material.

In another aspect of the invention the pump is mounted on the truck with the chute at a level above the ground not exceeding 1 ,500mm. Preferably, the pump is mounted on the truck with the chute located at a level above the ground lying in the range of 900mm to 1 ,500mm. Advantageously, the pump is mounted on the truck with the chute located at a level above the ground lying in the range of 1 ,000mm to

1 ,200mm. Ideally, the pump is mounted on the truck with the chute at a level above the ground of approximately 1 ,100mm. Preferably, the pump is located on the truck to the rear thereof. Advantageously, the pump is located to one side of the truck.

In another aspect of the invention a solid matter storage camber is located on the truck, and the pump is located to the rear and to one side of the solid matter storage chamber. In a further aspect of the invention the truck comprises a compactor located rearwardly of the solid matter storage chamber, and the pump is located rearwardly and to one side of the compactor.

In one embodiment of the invention the pumpable material storage chamber is located on top of the solid matter storage chamber.

In an alternative aspect of the invention the pumpable material storage chamber is located to one of the front and rear of the solid matter storage chamber. Preferably, the pumpable material storage chamber is located in front of the solid matter storage chamber.

In another aspect of the invention a driver's cab is provided. In a further aspect of the invention the pumpable material storage chamber is located intermediate the driver's cab and the solid matter storage chamber.

Advantageously, the pump comprises a pump according to the invention.

Further the invention provides a method for pumping a pumpable material into a pumpable material storage chamber of a waste disposal truck, the method comprising providing a pump onjthe waste disposal truck, delivering the pumpable material into a pump chamber of the pump through an inlet port thereof, and urging a piston from a first state to the second state to sweep the piston through the pump chamber for displacing the pumpable material from the pump chamber to the pumpable material storage chamber.

Preferably, the pump is located at a level on the truck whereby a person carrying a container of pumpable material can discharge the pumpable material from the container into the pump chamber by manually tipping the container for discharging the pumpable material into the pump chamber.

The advantages of the invention are many. The pump according to the invention has many advantages. The pump according to the invention is of relatively simple construction, with a minimum number of components, and in particular a minimum number of moving parts, and requires no valves. Accordingly, the pump according to the invention is sturdy and operates substantially trouble free over long periods of time, and of most importance is reliable. Furthermore, the pump is particularly suitable for mounting on a waste disposal truck for pumping pumpable material into a pumpable material storage chamber of a waste disposal truck. In particular, the pump is particularly suitable for receiving pumpable domestic waste from a bin or a container, for example, a bucket carried by a person and manually tipped by the person for discharging the waste material from the bin or container into the pump. Due to the arrangement of the inlet port, a hopper is not required to direct the pumpable waste material into the pump chamber, and furthermore, the piston enters the pump chamber through the inlet port from the first state without having to cut through the pumpable waste material which in some cases may contain solid matter, which could damage the piston. By virtue of the fact that the drive means for urging the piston from the first state to the second state is disabled until the chute is in the guide state, there is little or no risk of injury to an operator as the piston is being urged from the first state to the second state to discharge pumpable waste material from the pump chamber, since the piston is inaccessible, due to the chute being in the guide state.

The waste disposal truck according to the invention has many advantages. A particularly important advantage of the waste disposal truck is that the pump on the waste disposal truck is located with the inlet port of the pump at a level which is suitable for receiving pumpable waste material from a bin or a container, for example, a bucket carried by a person and containing such domestic pumpable waste material, and manually tipped by the person for discharging the waste material from the bin or container into the pump. Additionally, the pump may be readily mounted in any convenient position where it can be readily accessed by an operator at a location adjacent where the operator normally works. This, thus, reduces the distance an operator has to carry the bin or container containing the pumpable waste material, thus reducing the workload of the operator and increasing the productivity of the operator.

The method according to the invention for pumping a pumpable material into a pumpable material storage chamber provides similar advantages to those discussed in connection with the pump and the waste disposal truck. The invention will be more clearly understood from the following description of some preferred embodiments thereof, which are given by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a pump according to the invention,

Fig. 2 is a perspective view of the pump of Fig. 1 with a portion of the pump in a different state to that of Fig. 1 , Fig. 3 is a cutaway perspective view of the pump of Fig. 1 ,

Fig 4 is a cutaway perspective view of the pump of Fig. 1 with a portion of the pump in a further different state to that of Fig. 3,

Fig 5. is another perspective view of the pump of Fig. 1 ,

Fig. 6 is a rear elevational view of the pump of Fig. 1 , Fig. 7 is a side elevational view of the pump of Fig. 1 ,

Fig. 8 is a side elevational view of the pump of Fig. 1 from the opposite side to that of Fig. 7,

Fig. 9 is a cross-sectional side elevational view of the pump of Fig. 1 on the line IX-IX of Fig. 6,

Fig. 10 is a side elevational view of the pump of Fig. 1 with a portion of the pump in a different state to that of Fig. 9,

Fig. 11 is a cross-sectional side elevational view of the pump of Fig. 1 from the other side to that of Fig. 10,

Fig. 12 is a cross-sectional side elevational view similar to that of Fig. 9 of the pump of Fig. 1 with a portion of the pump of Fig. 1 in a different state to that of Fig. 9,

Fig. 13 is a side elevational view of a waste disposal truck according the invention comprising the pump of Fig.1 ,

Fig. 14 is a rear end elevational view of the waste disposal truck of Fig. 13,

Fig. 15 illustrates a portion of an hydraulic circuit of the truck of Fig. 13, Fig. 16 is a cross-sectional front elevational view of a pump according to another embodiment of the invention,

Fig. 17 is a front elevational view of the pump of Fig. 16 illustrating a portion of the pump in a different state,

Fig. 18 is a front elevational view of the pump of Fig. 16 with a portion of the pump in a further different state, and Fig. 9 is a side elevational view of a waste disposal truck according to another embodiment of the invention comprising the pump of Fig. 1.

Referring to the drawings and initially to Figs. 1 to 15 thereof, there is illustrated a waste disposal truck according to the invention indicated generally by the reference numeral 1 , see in particular Figs. 13 and 14, for collecting solid matter waste material such as, for example, domestic recyclable waste materials, for example, paper, plastic, glass, and other such recyclable materials; non-recyclable residual waste, for example, nappies, contaminated packaging, and for collecting pumpable material, such as, for example, biodegradable household food and kitchen waste of the type hereinabove described.

The waste disposal truck 1 comprises a chassis 2 supported on ground engaging wheels 3. A driver's cab 5 is mounted on the chassis 2, and a solid matter storage chamber 6 is located on the chassis 2 to the rear of the driver's cab 5 for storing the solid matter waste material. A compactor 7 is located to the rear of the solid matter storage chamber 6 for compacting solid matter waste material. The compactor 7 communicates with the solid matter storage chamber 6 for delivering the compacted solid matter waste material into the solid matter storage chamber 6. A pumpable material storage chamber 9 is located on top of the solid matter storage chamber 6 for storing the pumpable material. A pump also according to the invention and indicated generally by the reference numeral 10 is mounted to the rear of the truck 1 and to one side thereof on the compactor 7 for pumping pumpable material to the pumpable material storage chamber 9. A conduit 12 extending from the pump 10 to the pumpable material storage chamber 9 delivers pumpable waste material pumped by the pump 10 up to the pumpable material storage chamber 9. Referring now in particular to Figs. 1 to 12, the pump 10, which will now be described, comprises a pump housing 15 which defines an elongated pump chamber 16 of a constant circular transverse cross-section which is adapted to extend vertically from a lower downstream end 17 to an upper upstream end 18. The pump housing 15 comprises a cylindrical peripheral wall 19 which defines the pump chamber 16 as a cylindrical pump chamber, and an end cap 20 which closes the lower downstream end 17 of the pump chamber 16. An outlet port 21 from the pump chamber 16 extends from the peripheral wall 19 adjacent the lower

downstream end 17 of the pump chamber 16. The conduit 12 connects the outlet port 21 to the pumpable material storage chamber 9. The pump chamber 16 terminates at its upstream end 18 in an upwardly facing open mouth 22 of circular shape which is defined by an upper edge 23 of the peripheral wall 19, and which forms an inlet port 24 to the pump chamber 16.

A sub-housing 25 extending upwardly from the pump housing 15 comprises a pair of side walls 26 and 27 which are joined by front and rear walls 28 and 29, respectively. The side walls 26 and 27 and the front and rear walls 28 and 29 extend upwardly from the pump housing 15, and terminate in an anchorage 31. The anchorage 31 comprises a pair of anchor brackets 32 extending upwardly from the respective side walls 26 and 27.

A drive means comprising a double-acting hydraulic ram 33 is pivotally connected to the anchorage 31 , and carries a piston 35 for urging the piston 35 to sweep through the pump chamber 16 for displacing pumpable material therefrom, and for delivering the pumpable material through the outlet port 21 to the pumpable material storage chamber 9. The hydraulic ram 33 is located in the sub-housing 25 and comprises a cylinder 36 to which the piston 35 is mounted adjacent a lower end thereof. A piston rod 37 extending from the cylinder 36 of the hydraulic ram 33 terminates in a pivot mounting bracket 40 which is pivotally carried on a pivot pin 41 extending between and carried on the anchor brackets 32. The pivot pin 41 defines a transversely extending pivot axis 42 about which the hydraulic ram 33 is pivotal for facilitating pivoting of the piston 35 about the pivot axis 42 forwardly and rearwardly within the sub-housing 25 as will be described below.

The hydraulic ram 33 is operable between a retracted state and an extended state for urging the piston 35 between a first state illustrated in Figs. 9 and 11 and a second state illustrated in Figs. 4 and 12. In the first state the piston 35 is located in a first location, which in this embodiment of the invention is within the sub-housing 25 and externally of and spaced apart from the pump chamber 16 above the inlet port 24. In the second state the piston 35 is located at a second location adjacent the downstream end 17 of the pump chamber 16. As the piston 35 is urged from the first location to the second location, the piston 35 is urged through the inlet port 24 and into the pump chamber 16, where it is swept through the pump chamber 16 from the upstream end 18 to the downstream end 17 for displacing pumpable material from the pump chamber 16 through the outlet port 21. The conduit 12 is coupled to the outlet port 21 of the pump 10 so that on the piston 35 being swept through the pump chamber 16 from the upstream end 18 to the downstream end 17 pumpable material displaced from the pump chamber 16 by the piston 35 is urged through the conduit 12 and in turn into the pumpable material storage chamber 9.

An inlet opening 45 is defined in the sub-housing 25 between the side walls 26 and 27 and a lower edge 46 of the front wall 28 of the sub-housing 25 and a portion of the upper edge 23 of the peripheral wall 19 of the pump housing 15. The inlet opening 45 communicates with the inlet port 24 through the sub-housing 25 for accommodating pumpable material into the pump chamber 6 through the inlet port 24 when the piston 35 is in the first state spaced apart above the inlet port 24.

A chute 47 which is pivotally coupled to the side walls 26 and 27 of the sub-housing 25 on a pivot shaft 48 extending between the side walls 26 and 27 receives pumpable material and directs the pumpable material into the pump chamber 16 through the inlet opening 45 and in turn through the inlet port 24. The chute 47 is in the form of a tray 49 comprising a base 50, a pair of side walls 51 extending upwardly from the base 50, and a front end wall 52 extending upwardly from the base 50 between the side walls 51. The side walls 26 and 27 of the sub-housing 25 are configured adjacent the chute 47 to define a pair of arcuate elements 53 which co-operate with inner ends 54 of the side walls 51 of the tray 49 to sealably engage the side walls 51 of the chute 47. The pivot shaft 48 is pivotally carried on the arcuate elements 53. The chute 47 is pivotal from a receiving state illustrated in Fig. 1 , 5, 10 and 11 for receiving and directing pumpable material into the pump chamber 16, and a guide state illustrated in Figs. 2 to 4 and 7 to 9 for closing the inlet opening 45 and for guiding the piston 35 as will be described below.

A handle 55 mounted on the base 50 of the tray 49 of the chute 47 is provided for urging the chute 47 between the receiving state and the guide state. The handle 55 terminates in latches 56 and is pivotally coupled to the base 50 of the chute 47 for selectively engaging and disengaging the latches 56 in corresponding receivers 57 and 58 in the arcuate elements 53 for retaining the chute 47 in the receiving state and the guide state, respectively.

A guide means, which in this embodiment of the invention comprises a guide wall 60 located in the sub-housing 25 opposite the inlet opening 45, and formed by a lower inwardly downwardly inclined portion of the rear wall 29 of the sub-housing 25, guides the piston 35 from the first state into the pump chamber 16 through the inlet port 24. The guide wall 60 is of arcuate shape in plan view as well as inclining inwardly downwardly towards the inlet port 24 and co-operates with the piston 35 for guiding the piston 35 from the first state into the pump chamber 16 through the inlet port 24. Additionally, the base 50 of the tray 49 of the chute 47 when in the guide state is also engageable with the piston 35 as the piston 35 is being urged into the inlet port 24, and co-operates with the guide wall 60 to act as a guide means for guiding the piston 35 into the inlet port 24 as the piston 35 is being urged from the first state into the pump chamber 16.

A resilient urging means, in this embodiment of the invention a torsion spring 62 located around the pivot pin 41 and acting between the hydraulic ram 33 and the anchor brackets 32 of the sub-housing 25 urges the piston 35 about the pivot axis 42 into engagement with the guide wall 60 while the piston 35 is in the first state, and also as the piston 35 is being urged between the first state and the inlet port 24 of the pump chamber 16. Referring now to Fig. 15 there is illustrated an hydraulic circuit 63 through which the hydraulic ram 33 is powered for in turn operating the piston 35 between the first and second states. The hydraulic circuit 63 comprises an hydraulic control circuit 64 which comprises a series of valves (not shown) for selectively and alternately applying pressurised hydraulic fluid to ports 65 of the hydraulic ram 33. The construction of such hydraulic control circuits as the hydraulic control circuit 64 will be known to those skilled in the art. A pressurised hydraulic fluid source 66 is provided on the waste disposal truck 1 for providing hydraulic fluid to the hydraulic ram 33 through the control circuit 64. The pressurised hydraulic fluid source 66 powers other hydraulic equipment of the waste disposal truck 1 as will be

understood by those skilled in the art. A disabling means, in this embodiment of the invention a plunger operated normally closed hydraulic isolating valve 67 is located in an hydraulic fluid line between the hydraulic control circuit 64 and the port 65a of the hydraulic ram 33 for selectively isolating the port 65a from the hydraulic control circuit 64 in order to disable the hydraulic ram 33, and in turn to prevent the hydraulic ram 33 urging the piston 35 between the first and second states. The isolating valve 67 comprises a plunger 68 for operating the isolating valve 67 from the normally closed state to the open state. Depression of the plunger 68 in the direction of the arrow X operates the isolating valve 67 from the normally closed state to the open state.

The isolating valve 67 is mounted on the front wall 28 of the sub-housing 25 adjacent and just above the inlet opening 45, so that the plunger 68 of the isolating valve 67 is engaged and depressed in the direction of the arrow X by the chute 47 when the chute 47 is in the guide state, in order to operate the isolating valve 67, in the open state to thereby allow the flow of hydraulic fluid between the control circuit 64 and the hydraulic ram 33 to operate the piston 35 between the first and second states. Accordingly, for so long as the chute 47 is not in the guide state, the isolating valve 67 remains in the normally closed state thereby preventing operation of the piston 35 between the first and second states. Once the chute 47 is urged into the guide state, the chute 47 engages and depresses the plunger 68 in the direction of the arrow X, thereby operating the isolating valve 67 from the normally closed state to the open state, to permit the flow of hydraulic fluid between the control circuit 64 and ram 33, for in turn urging the piston 35 between the first and second states. The provision of the isolating valve 67 avoids any danger of the piston 35 being operated when the chute 47 is not in the guide state closing the inlet opening 45 in order to avoid any risk of injury to an operator. Returning now to the waste disposal truck 1 , the pump 10 is mounted to the rear and to one side of the truck 1 on the compactor 7 with the pump chamber 16 extending in a generally vertical direction and with the upstream end 18 thereof above the downstream end 17 thereof. The inlet opening 45 of the pump 10 faces generally rearwardly, and the chute 47 in the receiving state extends from the pump 10 in a generally rearwardly direction from the truck 1. Additionally, the pump 10 is mounted on the compactor 7 at a level so that the chute 47 when in the receiving state is at a level at which a container, for example, a bin or a bucket type container being carried by a person and containing pumpable material, for example, food waste can be discharged onto the chute 47 by manually tipping the bin or bucket type container to direct the pumpable material onto the chute 47. In this embodiment of the invention the chute 47 when in the receiving state is at a level not greater than 1 ,500mm above the ground. Providing the chute 47 when in the receiving state at a level no greater than 1 ,500mm above the ground allows a person carrying a typical bucket type waste container comprising food waste by its handle to raise and tip the container in order to discharge the food waste onto the chute 47. However, it is envisaged that the pump 10 may be mounted on the truck, with the chute 47 when in the receiving state at a level above the ground in the range of 900mm to 1 ,500mm, although ideally, the chute 47 when in the receiving state should be at a level above the ground in the range of 1 ,000mm to 1 ,200mm. It has been found that mounting the pump 10 on the waste disposal truck 1 with the chute 47 when in the receiving state at a level of approximately 1 ,100mm above the ground provides the chute 47 at a particularly comfortable level for a person of average height to manually lift a typical bucket type waste container, by its handle, containing household food and kitchen waste, and to manually tip the container to discharge the household food and kitchen waste onto the chute 47.

The level above the ground at which the chute 47 in the receiving state can be located is largely a compromise between the vertical length of the pump chamber between the upstream and downstream ends, which essentially determines the volume of the pump chamber, and the ideal level at which the chute 47 in the receiving state should be above the ground. As discussed above, the outlet port 21 is coupled to the conduit 12 for

accommodating the pumpable material pumped from the pump 10 to the pumpable material storage chamber 9. The hydraulic ram 33 is powered by the hydraulic system of the truck 1. In use, with the pump 10 mounted on the waste disposal truck 1 and with the outlet port 21 of the pump 0 connected by the conduit 12 to the pumpable material storage chamber 9, and with the hydraulic ram 33 connected to the hydraulic system of the truck 1 , the waste disposal truck 1 is ready for use. Solid waste is delivered into the compactor 7 in conventional manner, and is compacted by the compactor 7, and the compacted solid matter is then transferred by the compactor 7 into the solid matter storage chamber 6.

With the chute 47 secured in the receiving state by the latches 56 engaging the receivers 57 in the arcuate elements 53, and with the hydraulic ram 33 in the retracted state, and in turn with the piston 35 in the first state, the pumpable material, for example, food waste in a bin or other suitable container carried by a person, is tipped from the bin or container onto the chute 47. The food waste is then directed by the chute 47 through the inlet opening 45 in the sub-housing 25, and in turn through the inlet port 24 into the pump chamber 16.

When the pump chamber 16 has been fully charged with the pumpable waste material, the chute 47 is pivoted from the receiving state to the guide state and is secured in the guide state by the latches 56 engaging the receivers 58 of the arcuate elements 53. With the chute 47 in the guide state, the isolating valve 67 is operated into the open state, and the hydraulic ram 33 is then operated from the retracted state to the extended state for urging the piston 35 from the first state through the inlet port 24, and in turn into the pump chamber 16. As the hydraulic ram 33 continues to urge the piston 35 into the pump chamber 16, the piston 35 is swept through the pump chamber 16 to the second state for, in turn, displacing the pumpable material from the pump chamber 16 through the outlet port 21 , and in turn through the conduit 12 to the pumpable material storage chamber 9. With the chute 47 still in the guide state and holding the isolating valve 67 in the open state, the hydraulic ram 33 is then retracted to return the piston 35 from the second state to the first state. The chute 47 is pivoted from the guide state to the receiving state and is secured in the receiving state by engaging the latches 56 in the receivers 57 in the arcuate elements 53. With the chute 47 in the receiving state the isolating valve 67 is in the normally closed state, thereby preventing operation of the hydraulic ram 33, and in turn the piston 35. The pump 10 is then ready to receive the next batch of pumpable material.

Referring now to Figs. 16 to 18 there is illustrated a pump according to another embodiment of the invention indicated generally by the reference numeral 70. The pump 70 is substantially similar to the pump 10 and similar components are identified by the same reference numerals. The pump 70 is also suitable for mounting on the waste disposal truck 1 for pumping pumpable material up to the pumpable material storage chamber 9.

In this embodiment of the invention the pump housing 15 comprises a peripheral wall 19 which is closed at its lower downstream end 17 by an end cap 20, and defines the pump chamber 16. An upper edge 23 of the peripheral wall 19 defines an upwardly facing open mouth 22 which forms the inlet port 24 to the pump chamber 16. A piston 35 is connected by a cylindrical housing 71 to a pair of anchorages 72. However, in this embodiment of the invention the piston 35 is retained stationary by the anchorages 72, and the pump housing 15 is moveable between a first state illustrated in Fig. 16 and a second state illustrated in Fig. 17. In the first state the piston 35 is spaced apart above the inlet port 24 and defines with the upper edge 23 of the peripheral wall 19 of the pump housing 15 an inlet opening 45 through which pumpable material is delivered through the inlet port 24, and in turn into the pump chamber 16. In this embodiment of the invention an outlet port 74 is located in the piston 35 and communicates with the pump chamber 16 through the piston 35. The outlet port 74 is connected to the pumpable material storage chamber (not shown) by a conduit 12 extending from the outlet port 74.

A pair of spaced apart double acting hydraulic rams 75 are operably coupled between the pump housing 15 and the pair of anchorages 72 and are operable between an extended state illustrated in Fig. 16 with the pump housing 15 in the first state, and a retracted state illustrated in Fig. 17 with the pump housing 15 in the second state for urging the piston 35 through the inlet port 24 and for sweeping the piston 35 through the pump chamber 16 from the first state to the second state, for in turn displacing pumpable material from the pump chamber 16 through the outlet port 74 in the piston 35.

In use, with the pump 70 mounted on the truck 1 and secured to the compactor 7 to the rear, and to one side thereof with the inlet port 24 facing upwardly, and with the outlet port 74 connected by the conduit 12 to the pumpable material storage chamber, and with the hydraulic rams 75 connected to the hydraulic system of the truck 1 , the truck 1 with the pump 70 mounted thereon is ready for use. With the hydraulic rams 75 in the extended state, and in turn, with the pump housing 15 in the first state, pumpable material is delivered into the pump chamber 16 through the inlet opening 45 and in turn through the inlet port 24. When the pump chamber 16 is fully charged with pumpable material, the hydraulic rams 75 are operated from the extended state to the retracted state for urging the pump housing 5 from the first state to the second state for in turn urging the piston 35 into the pump chamber 16 through the inlet port 24, and for in turn sweeping the piston 35 through the pump chamber 16 in order to displace the pumpable material from the pump chamber 16 through the outlet port 74 in the piston 35, and in turn through the conduit 12 to the pumpable material storage chamber. When the pumpable material has been fully discharged from the pump chamber 16 to the pumpable material storage chamber, the hydraulic rams 75 are operated from the retracted state to the extended state for in turn urging the pump housing 15 from the second state to the first state so that the pump 70 is ready to receive the next batch of pumpable material. It is envisaged that a chute similar to the chute 47 may be provided for directing and delivering pumpable material into the pump chamber 16 through the inlet opening 45 and in turn through the inlet port 24.

Referring now to Fig. 19, there is illustrated a waste disposal truck according to another embodiment of the invention indicated by the reference numeral 80. The truck 80 is substantially similar to the truck 1 and similar components are identified by the same reference numerals. The pump 10 which is described with reference to Figs. 1 to 12 is mounted on the truck and is secured to the compactor 7 to the rear of the compactor 7 and to one side thereof. The only difference between the truck 80 and the truck 1 is that the pumpable material storage chamber 9 instead of being mounted on top of the solid matter storage chamber 6 is located on the chassis 2 of the truck 80 between the driver's cab 5 and the solid matter storage chamber 6.

Otherwise, the waste disposal truck 80 and its use and operation are similar to the waste disposal truck 1.

While the drive means for urging the piston of the pump 10 between the first and second states, and while the drive means for urging the housing of the pump 70 between the first and second states have been described as comprising double acting hydraulic rams, it is envisaged that the rams may be single acting hydraulic rams with a spring return. Needless to say, the drive means could also be provided by pneumatic rams, either double acting or single acting. It will also be appreciated that any other suitable drive means besides hydraulic or pneumatic rams may be provided.

It will also be appreciated that the pumps 10 and 70 may be used for purposes other than mounting on a waste disposal truck, and needless to say, the pumps 10 and 70 are suitable for pumping any type of pumpable material, be it a liquid, a liquid slurry material, a mixture of liquid and solid matter or any other pumpable material.

Needless to say, the pumps 10 and 70 may be mounted on any other types of trucks for pumping any other type of material besides waste material. It is also envisaged that the pumps 10 and 70, as well as being provided for pumping pumpable material into a pumpable material storage chamber, may also be provided for pumping pumpable material from the pumpable material storage chamber, whether the pumpable material storage chamber is located on a truck or otherwise. While particular constructions of pumps have been described for use with a waste disposal truck, it is envisaged that in certain cases the waste disposal trucks may be provided with different types of pumps, which may not necessarily be pumps according to the invention. However, it is important that the pump be located so that an inlet port of the pump or a chute which delivers pumpable material to the inlet port of the pump is located at a level which is convenient for a person carrying a bin of pumpable material on his or her shoulder can by forwardly tipping the bin while on his or her shoulder can readily easily deliver the pumpable material from the bin onto a chute or through an inlet port of the pump. It is also envisaged that the inlet port may be defined between the piston and the pump housing. Further, it is envisaged that the inlet port may be formed in the pump housing, for example, in the peripheral wall of the pump housing adjacent the upstream end thereof. In which case, the piston would be urged from the first state adjacent the upstream end of the pump chamber past the inlet port to the second state to thereby sweep through the pump chamber for pumping the pumpable material from the pump chamber through the outlet port thereof.

It will also be appreciated that the chute 47 need not act as a guide means when in the guide state, rather, it is envisaged in such cases that the chute 47 could be pivoted from the receiving state to a closed state, whereby the chute would merely close the inlet opening.

While it is desirable, particularly, from a safety point of view, it is not essential that an isolating valve be provided to isolate the hydraulic ram from the hydraulic control circuit, in order to prevent operation of the piston between the first and second states when the chute is not in the guide state. However, where it is desired to disable the piston when the chute is not in the guide state, any other suitable disabling means may be provided. It will also be appreciated that other suitable isolating valves may be provided, for example, such an isolating valve could be hydraulically controlled by a pilot hydraulic circuit, which would be configured to detect when the chute is in the guide state, or alternatively, the isolating valve may be operable by a solenoid or other suitable electrically powered operating means, and in which case, a detecting circuit, for example, an electrical or an electronic circuit would be provided to detect the state of the chute, and in particular, to detect when the chute is in the guide state.

It is also envisaged that the hydraulic control circuit or another control circuit, for example, an electronic control circuit may be configured to activate the hydraulic ram to urge the piston from the first state to the second state to discharge the pumpable waste material from the pump chamber in response to the chute being urged into the guide state, and then to return the piston the first state.