Counterweight assembly

A counterweight assembly for a working machine comprising a counterweight having a mass for counterbalancing a working arm of the working machine, the counterweight comprising a mounting arrangement for the mounting of a heat exchanger thereon and defining an air flow path having an inlet and an outlet to permit air to flow through the heat exchanger when mounted thereon.

FIELD OF THE INVENTION

The present invention relates to a counterweight assembly for a working machine and to a method of manufacturing a counterweight assembly for a working machine.

BACKGROUND OF THE INVENTION

Various types of working machines are known. Such machines are used typically for soil-shifting operations (e.g. trenching, grading, and loading) and materials handling (e.g. depositing aggregate in trenches, lifting materials and placing them on an elevated platform).

Such machines are typically manufactured from a set of subassemblies designed specifically for one type of machine, although certain components such as engines, gearboxes, hydraulic pumps and counterweights may be shared across different machine types.

The working machines typically include a working arm arrangement for manipulating an attachment, such as a bucket, and a counterweight to balance the working machine when the working arm is in use.

Working machines typically include an operator cab unit and an air conditioning unit for the cab unit. Typically, the air conditioning unit is mounted onto the roof or the back of the operator cab unit which is problematic as it may increase the overall height of the working machine, impact on the visibility of the operator or overhang the rotational envelope of a machine, where it may become susceptible to damage.

The present invention seeks to overcome or at least mitigate the problems of the prior art.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a counterweight assembly for a working machine comprising a counterweight having a mass for counterbalancing a working arm of the working machine, the counterweight comprising a mounting arrangement for the mounting of a heat exchanger thereon and defining an air flow path having an inlet and an outlet to permit air to flow through the heat exchanger when mounted thereon.

Advantageously, this provides a compact packaging of the heat exchanger. This arrangement may decrease the overall height of the working machine. Further, this arrangement minimizes the impact on visibility and may minimize the amount of machine overhang. It may additional protect the heat exchanger from impact damage.

In one embodiment, a heat exchanger is mounted to the mounting arrangement.

In one embodiment, the mounting arrangement is configured such that the heat exchanger is enclosed on four sides.

Advantageously, this further provides protection of the heat exchanger unit from damage. Further, this may enhance air flow through the heat exchanger by virtue of convection effects.

In one embodiment, the counterweight is configured to define an air flow path in the form of a duct therethrough.

In one embodiment, a fan is mounted in conjunction with the heat exchanger.

In one embodiment, the counterweight comprises a top surface, a bottom surface and at least one side surface.

In one embodiment, the mounting arrangement is located proximate the bottom surface.

In one embodiment, the counterweight assembly further comprises a grill, wherein the grille is mounted proximate the top surface.

Advantageously, this may prevent and debris from falling into the duct.

In one embodiment, the mounting arrangement is located proximate the top surface of the counterweight assembly.

In one embodiment, the mounting arrangement is located proximate a side surface of the counterweight assembly.

In one embodiment, the mounting arrangement comprises a plurality of threaded bores.

In one embodiment, the duct is configured to define at least one mounting surface which includes the plurality of threaded bores.

In one embodiment, when the heat exchanger is mounted to the mounting assembly the heat exchanger abuts against the or each mounting surface.

In one embodiment, the counterweight is formed as a single unitary component, for example a cast iron or steel component.

In one embodiment, the heat exchanger is a condenser of an air conditioning system.

In one embodiment, the fan is configured to drive air through the inlet, through the condenser to the outlet.

A second aspect of the invention provides a working machine comprising a working arm configured so as to be capable of performing working operations, and a counterweight assembly according to the first aspect.

Advantageously, this provides a compact packaging of the heat exchanger. This arrangement may decrease the overall height of the working machine. Further, this arrangement minimizes the impact on visibility and may minimize the amount of machine overhang. It may additional protect the heat exchanger from impact damage.

In one embodiment, the working machine further comprises an operator cab and wherein the heat exchanger is a condenser of an air conditioning unit for the operator cab.

A further aspect of the invention provides a method of manufacturing a counterweight with a heat exchanger mounted therein, comprising the steps of: producing a counterweight comprising an air flow path and a mounting arrangement; and mounting a heat exchanger to mounting arrangement.

In one embodiment, the heat exchanger is a condenser of an air conditioning unit.

In one embodiment, the air flow path defines a duct.

In one embodiment, the method further comprises the step of securing a fan to the condenser.

In one embodiment, the method further comprises the step of securing a grille to the fan.

DETAILED DESCRIPTION

With reference toFIG. 1, there is illustrated in somewhat simplified form a working machine10according to an embodiment of the present invention, in this case a wheeled slew excavator. The machine comprises an undercarriage12and a superstructure14linked by a slewing mechanism in the form of a slew ring16. The slew ring16permits unrestricted rotation of the superstructure14relative to the undercarriage12in this embodiment. A working arm arrangement40is rotatably mounted to the superstructure14and provided for performing material handling operations.

The undercarriage is connected to a ground engaging structure, comprising four wheels19a,19b,19c,19d.The wheels19a,19b,19c,19d,are typically provided with off-road pneumatic tires.

A dozer blade arrangement22is pivotally secured to one end of the undercarriage12, which may be raised and lowered by hydraulic cylinders21using a known arrangement, and also act as a stabilizer for the machine, by lifting the adjacent wheels19a,19boff the ground when excavating.

A stabilizer leg arrangement24is pivotally mounted to an opposite end of the undercarriage12to the dozer blade assembly22, which also may be raised and lowered by hydraulic cylinders23using a known arrangement.

The superstructure14comprises a structural platform26mounted on the slew ring16. As can be seen in the Figure, the slew ring16is substantially central to the undercarriage12so as to mount the superstructure14central to the undercarriage. The slew ring16permits rotation of the superstructure14relative to the undercarriage12.

The platform26mounts a cab30. The cab30houses the operator's seat and machine controls. The cab30is mounted forwards and to the left of the superstructure14in this embodiment and is fixed for rotation together with the superstructure. In plan view the cab30is substantially rectangular and has a substantially vertical rear wall36and right hand side wall (not visible).

The superstructure14further comprises a counterweight34to counterbalance the working arm arrangement40and positioned at an aft end of the superstructure opposite to the working arm40to optimize the counterbalance effect.

In this embodiment a prime mover, main hydraulic pump, and transmission (not shown) for the working machine10are located in the undercarriage12, but in other embodiments the engine and main hydraulic pump are located in the superstructure14.

Referring toFIG. 2, the counterweight assembly150incorporating the counterweight34is illustrated in more detail. The counterweight34has an upper surface158and a lower surface160which are substantially parallel to each other, a vertical front surface162configured to be positioned against the rear wall36of the cab30, and an angled surface164at the point furthest from the cab. Consequently, the counterweight34is substantially a right angled trapezium in side view. The counterweight34defines a segment of a circle in plan view by virtue of the angled surface164also being curved.

This curved shape serves to minimize the overhang of the superstructure14relative to the undercarriage12across the full range of rotation of the superstructure such that the working machine may be considered to be a compact tail swing (CTS) or a zero tail swing (ZTS) excavator.

In this embodiment, the front surface162of the counterweight34is configured with a recess163for a compact fit against the rear of the cab30and the recess extends substantially half of the width of the counterweight34and the recess of the counterweight is shown positioned against a cab in the Figure. The counterweight34protrudes upwardly from the platform26by a distance that is ¼ to ⅓ of the height of the cab30. Such a height has been found to have limited impedance on an operator's line of sight across a range of operating modes. That is, an operator's line of sight is improved when looking over their shoulder.

In this embodiment, the counterweight34is cast a single component and is produced to define an air flow path172therethrough and a mounting arrangement178by using a suitable core as part of the casting process. The counterweight assembly150comprises a counterweight34, a condenser152of an air conditioning unit, a twin electric fan154and a fan mounting frame156. In alternative embodiments the fan154may be hydraulically powered.

In this embodiment, the air flow path defines a duct172formed through the counterweight34defining an inlet and an outlet. The duct172defines two regions through the counterweight34, the first174is substantially rectangular in shape at the inlet to conform to the shape of the condenser152, and the second176is narrower than the first so as to provide the mounting surface178. In this embodiment, the mounting surface is provided in the form of a ledge178at the interface between the regions which extends around all four internal side of the duct. The first region174extends substantially perpendicular to the lower surface160and extends a distance which is substantially equal to the height of the condenser152, fan154and mount156system.

In this embodiment, the ledge178comprises four threaded bores180located in the four corners of the ledge for mounting the condenser152thereon. The condenser152further comprises four bores155located in the four corners defined by the rectangular shape of the condenser. The mounting frame156further comprises four bores157which are configured to align with the bores155of the condenser152when the condenser and frame are assembled.

Assembly of the counterweight assembly may be as follows: the electric fan154is secured to the mounting frame156and the fan and frame arrangement is then the condenser152is inserted into the frame so as to align the bores157of the mounting frame156with the bores155of the condenser154. The mounting frame156and condenser152are then secured to the threaded bores180of the ledge178via four elastomer mounts184.

A grille182is secured to the upper surface158of the counterweight150to prevent debris from falling into the duct172but configured to enable a sufficient air flow therethrough. In this embodiment, the electric fan154configured so as to drive air to flow through the inlet located proximate the lower surface160and flow through the condenser152and duct172and through the outlet located on the upper surface158of the counterweight34.

Referring toFIGS. 3, 4, 5, and 6, simplified schematic diagrams of alternative embodiments of the counterweight assembly are shown.

FIG. 3illustrates a counterweight where the condenser, fan and fan mount (not shown) are to be mounted into the upper surface258of the counterweight, corresponding components of this figure are labeled100higher with respect toFIGS. 1 and 2. Only differences are discussed in more detail. A duct272is formed through the counterweight134, having two regions. The first274is substantially rectangular in shape, and the second276is narrower so as to define a ledge278at the interface between the regions. A grille (not shown) may also be mounted over the counterweight for protection.

FIG. 4illustrates a counterweight where the condenser, fan and fan mount are to be mounted into the angled and curved surface of the counterweight, corresponding components of this figure are labeled100higher with respect toFIG. 3. Only differences are discussed in more detail. A duct372is formed through the counterweight234, having two regions. The first region374is substantially rectangular in shape, and the second region376is narrower so as to define a ledge378at the interface between the regions. The first region374extends substantially perpendicular to the curved surface364. The duct372extends into the angled surface364counterweight234and is configured to extending a general L-shape through the counterweight and provide an outlet on the upper surface358of the counterweight.

FIG. 5illustrates a counterweight according to an alternative embodiment of the present invention, corresponding components of this figure are labeled100higher with respect toFIG. 4. The counterweight334is generally a U-shape in plan view so as to define a channel488on one side of the counterweight, rather than an enclosed duct of the previous embodiments. In this embodiment, the condenser (not shown) will be surrounded by three sides of the counterweight334. In this embodiment the mounting arrangement478is provided in the form of a ledge extending around the three internal faces channel488. The condenser is then able to be mounted to the underside of the ledge478. The top and/or open side of the channel488may be covered by a grille (not shown). A protective plate (not shown) may be secured to the counterweight to protect the condenser etc. from impact damage.

FIG. 6illustrates a counterweight assembly according to an alternative embodiment of the present invention, corresponding components of this figure are labeled100higher with respect toFIG. 5. The arrangement is similar toFIG. 5except that the mounting arrangement578is provided by recesses586in two opposing sides of the channel588. In this embodiment, the condenser (not shown) are inserted into the counterweight434substantially horizontally and may be suitably retained with fasteners (not shown).

In an alternative embodiment, in which like parts are labeled by like numerals with the addition of the suffix ′, as illustrated inFIG. 7, the cab30′ is rotatably mounted to the superstructure14′. In this embodiment, the counterweight34′ has a curved profile in a region nearest the cab. The front38′ and rear36′ of the cab30′ each have a curved profile that is complimentary to the curved profile of the counterweight34′ to allow for rotation of the cab. The complimentary curved profiles accommodate rotation of the cab30′ relative to the superstructure14′ in a particularly compact manner. The rotation of the cab30′ relative to the superstructure14′ allows the working machine10′ to switch between a straight dig position where the counterweight34′ is behind the cab and a roading position where the counterweight assembly is in front of the cab. As shown in the Figure, the rear of the cab30′ extends over the upper surface158′ of the counterweight34′, and so in this embodiment the outlet of the duct172′ is located in the curved surface164′ of the counterweight. A grille182′ may further be mounted to the curved surface164′ of the counterweight to cover the outlet of the duct172′.

In other embodiments the counterweight may be formed via a plurality of complimentary sections which, when stacked and secured together, form a counterweight defining an air flow path therethrough and a mounting arrangement.

In the present invention the working machine may be considered to be a midi excavator. In other embodiments, the counterweight assembly may be fitted to other working machines for example a telehandler, a loader or a crane.

In other embodiments, a different form a heat exchanger, such as a radiator for cooling the engine, transmission, steering or hydraulic system for example, may be secured to the counterweight. Further, more than one heat exchanger may be mounted to the counterweight.

In other embodiments, the mounting arrangement may be in a different form, such as providing a ledge on two opposing sides of the duct with two threaded bores located in each ledge, or providing a protruding surface in each of the four corners of the duct with each ledge comprising a threaded bore therein.