A working machine

Abstract

A working machine comprising: an undercarriage mounted to a ground engaging structure; a superstructure rotatably mounted to the undercarriage; a working arm pivotally mounted to the superstructure; a

Description

FIELD The invention relates to a working machine. BACKGROUND Off-highway vehicles / working machines are typically those used in construction industries (e.g. backhoe loaders, slew excavators, telescopic handlers, forklifts, skid-steer loaders, dump trucks, bulldozers, graders), agricultural industries (e.g. tractors, combine harvesters, wheeled loading shovels, telescopic handlers, self-propelled harvesters and sprayers), quarrying (e.g. excavators, wheeled loading shovels, aggregate crushing equipment), and forestry (e.g. timber harvesters, feller bunchers). Many working machines have a primary function of moving material using either a lifting arm (e.g. a pivoting boom) or a working arm (e.g. an excavator arm) and may be referred to as material handling machines. Conventionally, working machines of the type referred to above are generally powered by diesel internal combustion engines. However, there is a general need to reduce vehicle emissions in the face of global warming leading to working machine OEMs considering alternative prime movers. Proposed alternatives include battery, hydrogen fuel cells, hydrogen internal combustion engines and various hybrid options, etc. The present invention seeks to provide a storage solution for a gaseous fuel for a working machine comprising a prime mover. SUMMARY The present teachings provide a working machine according to the appended claims. An aspect of the teachings provides a working machine. The working machine may comprise an undercarriage mounted to a ground engaging structure; a superstructure rotatably mounted to the undercarriage; and / or a working arm pivotally mounted to the superstructure. The working machine may comprise a prime mover, e.g. a gas engine, configured to provide motive power to the ground engaging structure. The working machine may comprise at least one storage tank for supplying hydrogen to the prime mover. Advantageously, providing a working machine with a prime mover and a storage tank reduces vehicle emissions in the face of global warming, thereby improving the sustainability of the working machine. The working machine may comprise an operator cab mounted to the superstructure. The operator cab may be offset relative to a central longitudinal axis of the superstructure on a first side of the body. The at least one storage tank may comprise a first storage tank on a second side of the superstructure remote from the operator cab. Advantageously, providing the storage tank on the opposite side to the operator cab may provide a convenient location for storing hydrogen. The location of the at least one storage tank provides natural protection and does not interfere with operator visibility. The storage tank may be located fully within the footprint of the working machine, thereby improving space efficiency of the material handling machine. The working machine may comprise a pivotal connection configured to pivotally mount the working arm to the superstructure. The pivotal connection may be located adjacent the at least one storage tank. The pivotal connection may be interposed between the operator cab and the first storage tank. Advantageously, providing the pivotal connection between the operator cab and the first storage tank provides a space efficient arrangement and helps to inhibit the first storage tank from obstructing movement of the working arm. The first storage tank may be arranged substantially parallel to a central longitudinal axis of the working machine. Advantageously, providing the first storage tank parallel to the central longitudinal axis helps to increase a possible length of the first storage tank in the longitudinal direction. The first storage tank may be housed within the superstructure. Advantageously, housing the first storage tank within the superstructure provides protection to the first storage tank and may help to increase operator visibility. The working machine may comprise an access step arrangement located on the superstructure adjacent the operator cab. The first storage tank may be housed underneath the access step arrangement. Advantageously, providing the storage tank underneath the access step arrangement may provide a convenient location for storing hydrogen. The location of the storage tank underneath the access arrangement provides natural protection and does not interfere with operator visibility. The storage tank may be located fully within the footprint of the working machine, thereby improving space efficiency of the material handling machine. The at least one storage tank may comprise the first storage tank and a second storage tank. The first storage tank may be stacked vertically on top of the second storage tank underneath the access step arrangement. Advantageously, providing first and second storage tanks increases the storage capacity. Providing the first and second storage tanks underneath the access step arrangement provides natural protection to the first and second storage tanks, is space efficient and does not interfere with operator visibility. The access step arrangement may comprise at least two access steps. A first end of each of the first and second storage tanks is offset so as to conform to a shape of the access step arrangement. Advantageously, providing the first and second storage tanks corresponding to the shape of the access step arrangement helps to improve space efficiency of the superstructure. The first and second storage tanks each comprise the first end located towards a front of the working machine and a second end located towards a rear of the working machine. The second ends may be vertically aligned and the first end of the second storage tank extends longitudinally beyond the first end of the first storage tank. Advantageously, this arrangement helps to improve space efficiency of the superstructure and increase storage capacity of the first and second storage tanks. The second storage tank may extend along a majority of the longitudinal length of the working machine. Advantageously, this arrangement increases storage capacity of the seconds storage tank. The working machine may define a front and a rear. The prime mover may be located at the rear of the working machine. Advantageously, this arrangement provides space for the first and second storage tanks, and may improve weight distribution of the working machine. The at least one storage tank may comprise one or more transverse tanks extending transversely with respect to a longitudinal axis of the working machine. Advantageously, providing transverse tanks may decrease space occupied by the storage tanks in a longitudinal direction. Additionally, providing transverse tanks enables the width of the machine to be utilised for storage, thereby increasing potential storage capacity. The one or more transverse tank may extend transversely across a majority of the working machine with respect to the longitudinal axis of the working machine. Advantageously, this arrangement increases the storage capacity of the transverse storage tanks. The one or more transverse storage tanks may comprise a plurality of transverse storage tanks. The plurality of transverse storage tanks may be arranged in a stacked configuration. Advantageously, this arrangement increases the storage capacity of the transverse storage tanks. The stacked configuration may improve space efficiency of the transverse storage tanks. The plurality of transverse storage tanks may occupy a majority of a height of the superstructure. Advantageously, this arrangement increases storage capacity of the transverse storage tanks and uses otherwise redundant space of the superstructure, thereby increasing space efficiency. The one or more transverse tanks may be arranged on the superstructure to be located in front of the prime mover. The working machine may comprise a counterweight mounted to a rear of the superstructure. The prime mover may be arranged in between, for example interposed between, the one or more transverse tank and the counterweight. Advantageously, this arrangement may help to improve airflow to the prime mover, noise and heat distribution, weight distribution and access to components for maintenance. The counterweight may have a recessed front face, and the prime mover may be arranged in the recess. Advantageously, this arrangement provides space between the prime mover and the operator, and enable isolation of the prime mover and storage tanks. The one or more transverse tanks may be located towards a rear of the working machine. An entirety of the prime mover may be located in front of the one or more transverse tank. The working machine may comprise an operator cab mounted to the superstructure. The prime mover may be located between the one or more transverse storage tanks and the operator cab when the working machine is viewed in side view. The prime mover may be longitudinally offset from the operator cab. The superstructure may comprise a prime mover housing. The at least one storage tank may comprise one or more housing storage tanks mounted above the prime mover housing. Advantageously, providing the one or more housing storage tanks above the prime mover housing helps to prevent the one or more housing storage tanks from obstructing / interfering with components located within the prime mover housing. The superstructure may comprise a tank housing for housing the one or more housing storage tanks. The tank housing may be mounted to an uppermost surface of the prime mover housing. Advantageously, the tank housing provides protection to the housing storage tanks. Additionally, the housing storage tanks and the tank housing can be provided as a subassembly, thereby improving ease of assembly. The one or more housing storage tank may be located rearward of the operator cab. Advantageously, providing the housing storage tank rearward of the operator cab may provide a convenient location for storing hydrogen. The housing storage tank may be located fully within the footprint of the working machine, thereby improving space efficiency of the material handling machine. The one or more housing tanks may not extend beyond an uppermost extent of the operator cab. Advantageously, this arrangement helps to improve operator visibility. The working machine may comprise a longitudinal axis. The one or more housing tanks may extend transversely across the superstructure with respect to the longitudinal axis. The one or more housing storage tanks may extend transversely across a majority of the superstructure with respect to the longitudinal axis. The one or more housing storage tanks may extend transversely across substantially an entirety of the superstructure with respect to the longitudinal axis. The one or more housing tanks may comprise two or more housing storage tanks, for example at least three housing storage tanks, and the two or more housing storage tanks may extend substantially parallel to one another. Advantageously, providing more than one tank on the working machine increases the storage capability of gaseous fuel on the working machine. Providing parallel storage tanks improves packing and space efficiency. The ground engaging structure may comprise a pair of tracks configured to move the working machine over a ground surface. The pair of tracks may be mounted to the undercarriage. The at least one storage tank may comprise one or more undercarriage storge tank mounted to the undercarriage. Advantageously, providing the undercarriage storage tank mounted to the undercarriage may provide a convenient location for storing hydrogen. The location of the undercarriage storage tank in the undercarriage provides natural protection and does not interfere with operator visibility. The undercarriage storage tank may be located fully within the footprint of the working machine, thereby improving space efficiency of the working machine. The one or more undercarriage storage tanks may comprise a first undercarriage storage tank extending longitudinally along a first side of the undercarriage, and / or a second undercarriage storage tank extending longitudinally along an opposing second side of the underca rriage. Advantageously, providing more than one undercarriage storage tank on the working machine increases the storage capability of hydrogen on the working machine. Providing the undercarriage storage tanks on opposing sides improves weight distribution of the undercarriage. A first of the pair of tracks may surround the first undercarriage storage tank. A second of the pair of tracks may surround the second undercarriage storage tank. The one or more undercarriage storage tanks may extend longitudinally with respect to a central longitudinal axis of the working machine. Advantageously, providing the one or more undercarriage storage tanks extending longitudinally may increase the storage capability of the one or more undercarriage storage tanks by corresponding to the longest dimension of the undercarriage. The one or more undercarriage storage tanks may be located substantially centrally with respect to an elongate length of the undercarriage. Advantageously, this arrangement may improve weight distribution of the undercarriage. The working machine may comprise an operator cab comprising a cab roof. The at least one storage tank may comprise one or more cab storage tanks mounted to the cab roof. Advantageously, the location of the roof storage tanks provides potential for a large amount of gaseous storage, thereby extending the duration of use between refuelling operations. The one or more cab storage tanks may be arranged longitudinally with respect to a longitudinal axis of the working machine. The one or more cab storage tanks may comprise two or more cab storage tanks. Advantageously, providing two or more cab storage tanks increases the storage capacity of gaseous fuel on the working machine. The one or more cab storage tanks may occupy a majority of a surface area of the cab roof. The one or more cab storage tanks may occupy substantially an entirety of the surface area of the cab roof. Advantageously, this arrangement increases storage capacity of gaseous fuel on the working machine. The one or more cab storage tanks may extend longitudinally beyond a front edge and / or a rear edge and / or a side edge of the cab roof. Advantageously, this arrangement increases storage capacity of gaseous fuel on the working machine. The cab roof may comprise a mounting frame to which the one or more cab storage tanks are mounted. The one or more cab storage tanks may each comprise an elongate cylinder having a neck portion at either end thereof. Each of the one or more cab storage tanks may be attached to the mounting frame via the neck portion. The mounting frame may comprise first and second neck attachments for attaching to respective neck portions at either end of the one or more cab storage tanks. The cab roof may comprise a mounting frame to which one or more cab storage tanks are mounted. The cab storage tanks may be attached to the mounting frame by a strap arrangement. The at least one storage tank may comprise one or more arm storage tanks mounted to the working arm. The working arm may comprise a first end coupled to the body and a second end remote form the body. The at least one storage tank may comprise a first storage tank mounted towards the first end of the working arm and / or a second storage tank mounted towards the second end of the working arm. The working arm may comprise a boom pivotally attached to the superstructure at a first end thereof and a dipper arm pivotally connected to a second end of the boom. The one or more storage tanks may be mounted to the boom and / or to the dipper arm. The working machine may comprise a rotary joint located at the connection between the undercarriage and the superstructure. The at least one storage tank may comprise a rotary joint storage tank extending through the rotary joint. The working machine may be an excavator. BRIEF DESCRIPTION OF DRAWINGS Embodiments will now be described by way of example only with reference to the accompanying figures, in which: Figure 1 is a left-side view of a working machine according to an embodiment of the present teachings; Figure 2 is a plan view of the working machine of Figure 1; Figure 3 is a right-side view of a working machine according to the present teachings; Figure 4 is a plan view of the working machine of Figure 3; Figure 5 is a right-side view of a working machine according to an embodiment of the present teachings; Figure 6 is a plan view of the working machine of Figure 5; Figure 7 is a right-side view of a working machine according to an embodiment of the present teachings; Figure 8 is a plan view of the working machine of Figure 7; Figure 9 is a right-side view of the working machine of Figure 7 with a tank housing removed; Figure 10 is a plan view of the working machine of Figure 9; Figure 11 is a left-side view of a working machine according to the present teachings; Figure 12 is a base view of an undercarriage of the working machine of any of Figure 11; Figure 13 is an isometric view of an undercarriage of a working machine according to the present teachings; and Figure 14 is an isometric view of an alternative embodiment of a working machine according to the present teachings. DETAILED DESCRIPTION In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and the teachings. However, those skilled in the art will understand that: the present teachings may be practiced without these specific details or with known equivalents of these specific details; that the present teachings are not limited to the described embodiments; and, that the present teachings may be practiced in a variety of alternative embodiments. It will also be appreciated that well known methods, procedures, components, and systems may not have been described in detail. References to vertical and horizontal in the present disclosure should be understood to be in relation to the machine when stood on horizontal ground in a non-working condition. The terms axial and longitudinal are generally used in relation to the longitudinal axis of the machine. The term width is generally used in relation to the longitudinal length, that is, transverse to the length. With reference to Figures 1 to 13, a working machine according to an embodiment of the present teaching is indicated generally at 10. The working machine 10 of the described embodiment is a material handling machine 10 in the form of an excavator. The excavator may be a slew excavator, a wheeled excavator, a tracked excavator, a crawler excavator or a compact excavator, by way of example. The working machine 10 is powered by a gaseous fuel. The gaseous fuel may be any suitable fuel such as compressed natural gas, hydrogen, landfill gas or biomass, for example, all of which are known in the art. However, it will be appreciated that the present disclosure may be applicable to other working machines which comprise a prime mover which is operable using a gaseous fuel. In the illustrated embodiment, the working machine 10 is an excavator having an undercarriage 12 mounted to a ground engaging structure 14a, 14b. The ground engaging structure 14a, 14b is provided in the form of a pair of tracks 14a, 14b configured to move the working machine 10 over a ground surface. In particular, the ground engaging structure 14a, 14b includes first and second tracks 14a, 14b located on opposing sides of the working machine 10. However, in alternative embodiments, an alternative ground engaging structure may be provided, for example a pair of front and rear wheels configured to move the working machine 10 over the ground surface, or any suitable number of wheels. The working machine 10 includes a front 10a, a rear 10b, a first side 10c (also referred to as a left side) and a second side lOd (also referred to as a right side or cab side) opposing the first side 10c. The left side 10c is taken to mean the side which is closest to the viewer when the working machine 10 is viewed from the left, and the right side lOd is taken to mean the side which is closest to the viewer when the vehicle 10 is viewed from the right. The working machine 10 includes a superstructure 16 rotatably mounted to the undercarriage 12 and a working arm 18, also known as a boom 18, pivotally mounted to the superstructure 16. The working machine 10 includes an operator cab 22 mounted to the superstructure 16. The operator cab 22 is offset relative to a central longitudinal axis a-a of the working machine 10 on the second side or right side lOd of the working machine 10. It shall be appreciated that in alternative embodiments, the operator cab 22 may be located substantially centrally relative to the central longitudinal axis a-a of the working machine 10. The operator cab 22 includes a cab roof 22a. The cab roof 22a may be understood to be an upper member of the operator cab 22 which provides a canopy under which an operator is located when operating the working machine 10. The operator cab 22 includes an operator seat and suitable controls for operating the working machine 10. Thus, there may be provided one or more of: a steering device, such as a steering wheel, lever or joystick for example, input devices for operating the working arm 18, such as a lever or joystick for example, speed control devices for controlling the movement of the working machine 10 over a ground surface, such as one or more foot controls (e.g. accelerator, brake), lever or joystick; a throttle control; one or more output devices for providing the operator with information pertaining to the operating state of the machine which may be visual (e.g. a display screen, warning lights) or audible (e.g. buzzer, speaker or other alarm); and, one or more input devices for configuring or operating various aspects of the machine (e.g. switches, levers, touch screen display, joysticks, touch buttons). The working machine 10 includes an access arrangement 24a, 24b, illustrated in Figure 1, located on the superstructure 16 adjacent the operator cab 22. It shall be appreciated that in some embodiments, for example when the excavator is a compact excavator, the access arrangement 24a, 24b may be omitted. The access arrangement 24a, 24b includes access steps 24a, 24b configured to provide access to the prime mover 15' and / or storage tanks of the working machine 10. In some embodiments, the access arrangement 24a, 24b may provide access to the operator cab 22. In the embodiment shown in the Figures, the access arrangement 24a, 24b includes two access steps 24a, 24b, however in alternative embodiments any suitable number of steps may be provided, for example at least one access step or at least two access steps 24a, 24b. The first access step 24a is an upper access step 24a and the second access step 24b is a lower access step 24b. The first and second access steps 24a, 24b are vertically offset. Put another way, the first and second access steps 24a, 24b each define a first end located towards the front 10a of the working machine 10, and the first end of the lower access step 24b is located closer to the front 10a of the working machine 10 than the first end of the upper access step 24a. In some embodiments, the first and second access steps 24a, 24b may be horizontally offset. One of the first or second access step 24a, 24b may be located closer to the central longitudinal axis a-a than the other of the first or second access step 24a, 24b. The working arm 18 is attached to the front 10a of the superstructure 16. The working machine 10 includes a pivotal connection 19 configured to pivotally mount the working arm B18 to the superstructure 16. The operator cab 22 is located adjacent the working arm 18. In the illustrated embodiments, the working arm 18 is centrally positioned. It shall be appreciated that in alternative embodiments, the working arm 18 may be mounted to the superstructure 16 towards the first side 10c or the second side lOd. The working arm 18 includes a boom 18a, illustrated in Figure 12, pivotally attached to the front 10a of the superstructure 16 at a first end of the working arm 18. The working arm 18 also includes a dipper arm 18b pivotally attached to the boom 18a and an implement, also known as an attachment, (not shown) pivotally attached to the dipper arm 18b (i.e. connected to a free end or second end of the working arm 18). In alternative embodiments, different configurations of the working arm B18 may be used. In some embodiments, the working arm 18 may be a triple-articulated boom (orTAB boom) comprising a boom, and a plurality of dipper arm sections pivotally attached between the boom and the implement. In some embodiments, the working arm 18 may include a boom and the dipper arm may be omitted. In some embodiments, the implement may be a bucket, which is used for material-shifting or materials handing operations (e.g. trenching, grading and loading) and / or material handling (e.g. depositing aggregate in trenches, lifting materials, and placing them on an elevated platform). It shall be appreciated that any alternative implements may be used. A boom actuator (not shown) is provided to move the boom in an ascending direction and a descending direction. The boom actuator is provided in the form of a boom actuator body defining a bore (not shown), a piston (not shown) configured for reciprocating movement within the bore, and a rod (not shown) connected to the piston and extending through the boom actuator body. The working machine 10 also includes a dipper actuator (not shown) similar to the boom actuator, for pivoting the dipper arm with respect to the boom, and an implement actuator, for example a bucket actuator, similar to the boom actuator, for pivoting the implement with respect to the dipper arm. In some embodiments, the working machine 10 may include a dozer blade (not shown) attached to the front of the working machine 10, as is known in the art. Furthermore, the working machine 10 may be used for towing operations, and may include a towing attachment (not shown). The working machine 10 includes a hydraulic system for controlling operations of the working machine 10. For example, the hydraulic system may control the boom actuator, dipper actuator, bucket actuator and other hydraulic functions of the working machine 10. The hydraulic system includes a hydraulic tank and a hydraulic pump or hydraulic pumps. The hydraulic pump may be used to drive hydraulic actuators used for operation of the lifting arm or some other hydraulic service or services. The hydraulic tank is operably connected to the working arm 18 via a series of control valves, rotary couplings, hoses and / or pipes. The control valves are controllable by an operator via controls to provide hydraulic fluid to the respective actuators of the working arm 18. Although not shown, in the illustrated embodiment, the hydraulic tank is mounted to the superstructure 16. However, it shall be appreciated that in alternative embodiments, the hydraulic tank may be mounted in a different position. In the illustrated embodiments, the working machine 10 is a slew excavator. Thus, the undercarriage 12 is connected to the superstructure 16 by a swivel, slew or rotary joint 23. The rotary joint may be used in conjunction with a slew ring configured to enable slewing, for example restricted slewing, of the superstructure 16. The working machine 10 includes an electric slew motor configured to control slewing of the superstructure 16. The electric slew motor may be located centrally within the undercarriage 12. It shall be appreciated that in alternative embodiments, the electric slew motor may be located at any suitable location on the working machine 10. The superstructure 16 includes a counterweight 28 provided at the rear of the superstructure 16. The counterweight 28 counterbalances the weight of the working arm 18 and any implement mounted thereto. As shown in Figure 2, the counterweight 28 spans laterally across the rear of the superstructure 16 and conforms to the shape of the working machine 10. In the illustrated embodiment, the counterweight 28 includes a metal casing (typically steel) filled with an aggregate material (typically concrete). However, in alternative embodiments, alternative types of counterweight may be used. The counterweight may be a bolt on counterweight, and additional counterweights or balances may be used. The superstructure 16 includes an internal volume 17 between the front 10a and the rear 10b of the working machine 10. In a typical equivalent diesel-powered machine, the internal volume 17 would ordinarily house the internal combustion engine (ICE), and may house its associated ancillary components include but not limited to fuel components and tanks, air inductions systems and / or exhaust system components. In the illustrated embodiments, the internal volume 17 housing various components of the hydrogen powered working machine 10. The housing of the superstructure 16 defining the internal volume 17 may therefore be referred to as prime mover housing, for example an engine housing 21 in embodiments where a gas engine 20 is provided, as well as a fuel storage housing 21. The working machine 10 includes a prime mover 20. The prime mover 20 may be a gas engine 20 configured to provide motive power to the ground engaging structure 14a, 14b and or to the hydraulic pump of the hydraulic system. In particular, the gas engine 20 is an internal combustion engine (ICE). It shall be appreciated that in alternative embodiments, the prime mover may be a fuel cell or any alternative prime mover. As such, the term "prime mover" is intended to cover fuel cells as well as gas engines. The drivetrain may include a hydraulically powered gearbox, a powershift gearbox, hydraulic travel motors and / or direct drive gearboxes, as is known in the art. In alternative embodiments, other prime movers and drivetrain types such as hydrostatic transmission and combinations thereof may be possible. The prime mover 20 is housed within the superstructure 16, for example in the engine housing 21. It shall be appreciated that in alternative embodiments, the prime mover 20 may be mounted to the undercarriage 12. The working machine 10 includes one or more storage tanks 26a-o in which gaseous fuel may be received and stored for use by the gas engine 20. The location of the storage tanks 26a-o may be anywhere suitable on the working machine 10, as will be described in more detail below. The storage tanks 26a-o are each generally torpedo shaped having a cylindrical central body with first and second hemispherical ends. The storage tanks 26a o are elongate. Each of the storage tanks 26a-o has a diameter in the range 200mm to 600mm, for example a diameter in the range 300mm to 500mm. In some embodiments, the storage tanks 26a-o have a longitudinal axis lying horizontal and transverse to the longitudinal axis a-a of the working machine 10. In other words, the storage tanks 26a-o may lie width-wise across the working machine 10 and perpendicular to the length of the working machine 10. In some embodiments, the storage tanks 26a-o have a longitudinal axis lying parallel to the longitudinal axis a-a of the working machine 10. In some embodiments, the storage tanks 26a-o have a longitudinal axis extending vertically and transverse to the longitudinal axis a-a of the working machine 10. In other words, the storage tanks 26a-o lie height-wise along the working machine 10 and perpendicular to the length of the working machine 10. In some embodiments, a combination of the above orientations may be used, and / or the storage tanks 26a-o may be arranged diagonally. An embodiment of the location of the at least one storage tank 26a, 26b is illustrated in Figures 1 and 2. In the embodiments of Figures 1 and 2, the at least one storage tank 26a, 26b is located on the first side 10c of the working machine 10 (or superstructure 16) remote from the operator cab 22. In the embodiment of Figures 1 and 2, two storage tanks 26a, 26b are provided. It shall be appreciated that in alternative embodiments, any suitable number of storage tanks 26a, 26b may be provided, for example one storage tank, three storage tanks or four storage tanks. Providing the first and second storage tanks 26a, 26b on the opposite side to the operator cab 22 provides a convenient location for storing hydrogen. The location of the at least one storage tank provides natural protection and does not interfere with operator visibility. The storage tank may be located fully within the footprint of the working machine 10, thereby improving space efficiency of the working machine 10. The first and second storage tanks 26a, 26b may have a storage capacity greater than 5kg, for example greater than 9kg, for example greater than 12kg. As will be appreciated, the first and second storage tanks 26a, 26b may use one or more gas lines (not shown) for filling and discharging gaseous fuel. Further, the first and second storage tanks 26a, 26b may include one or more valves 27a, 27b to control the flow of gas into and out of the storage tanks 26a, 26b. The gas lines may be referred to as conduits or pipework and may generally include an external cylindrical wall which defines a passageway to provide fluid communication for pressurised gas between various parts of the first and second storage tanks 26a, 26b and other parts of the working machine 10. In the embodiments of the present teachings, the first and seconds storage tanks 26a, 26b are each provided with an on-tank valve 27a, 27b, illustrated in Figure 2. The on-tank valve 27a, 27b, which may be referred to as a tank valve 27a, 27b, may be fitted to the first ends of the first and second storage tanks 26a, 26b. Providing the tank valves 27a, 27b in such a location provides convenient access for maintenance and the like. Providing the tank valves 27a, 27b adjacent one another is advantageous for providing easier installation and maintenance. The working machine 10 may include any suitable arrangement of access doors, access hatches, openable steps and / or access panels for providing access to the storage tanks 26a, 26b for maintenance. The first and second storage tanks 26a, 26b may be connected in series flow communication such that the first storage tank 26a includes an outlet in flow communication with the inlet of the second storage tank 26b. The first storage tank 26a may include a filling inlet valve which is in fluid communication with a filling nozzle inlet such that the first and second storage tanks 26a, 26b may be filled via the series connection. The filling nozzle may be configured to receive a corresponding nozzle of a refuelling device (not shown), as is well known in the art. The first and second storage tanks 26a, 26b may each include a pressure relief valve, such as a thermal pressure relief valve which is configured to open when the internal and / or external temperature of the first and / or second storage tanks 26a, 26b passes a preset temperature. The pressure relief valves from the first and second storge tanks 26a, 26b may be connected to a tank vent line. The pressure relief valves are configured to open in the event of increased pressure, or as a result of increased temperature from a fire. Once triggered, the pressurised content of the storage tanks 26a, 26b is rapidly discharged down the vent lines. It shall be appreciated that the above teachings relating to gas lines, tank valves 27a, 27b, series flow communication and pressure relief valves are applicable to each of the embodiments of Figures 1 to 14. As illustrated in Figure 2, the pivotal connection 19 for connecting the working arm 18 to the superstructure 16 is interposed between the operator cab 22 and the first and second storage tanks 26a, 26b. The first and second storage tanks 26a, 26b are arranged substantially parallel to the central longitudinal axis a-a of the working machine 10, i.e. longitudinally. As illustrated in Figures 1 and 2, the first and second storge tanks 26a, 26b are housed within the superstructure 16. In particular, the first and second storage tanks 26a, 26b are housed underneath the access step arrangement 24a, 24b. The first and seconds storage tanks 26a, 26b may therefore be referred to as access step storage tanks 26a, 26b. Providing the first and second storage tanks 26a, 26b housed underneath the access step arrangement 24a, 24b provides natural protection and does not interfere with operator visibility. The first storage tank 26a is vertically stacked on top of the second storage tank 26b underneath the access step arrangement 24a, 24b. As such, the first storage tank 26a may be referred to as the upper step storage tank 26a and the second storage tank 26b may be referred to as the lower step storage tank 26b. It shall be appreciated that the number of storage tanks 26a, 26b may correspond to the number of access steps 24a, 24b. For example, in embodiments where there are three access steps, there may be provided three storage tanks located underneath each of the three access steps. There may be provided any suitable number of storage tanks 26a, 26b, for example two or more upper step storage tanks 26a and two or more lower step storage tanks 26b. The number of storage tanks 26a, 26b may not correspond to the number of access steps 24a, 24b. The first and second storage tanks 26a, 26b are offset so as to conform to the shape of the access step arrangement 24a, 24b as illustrated in Figure 1. In particular, the first ends of each of the first and second storage tanks 26a, 26b are offset so as to conform to the shape of the access step arrangement 24a, 24b. The first ends of the first and second storage tanks 26a, 26b are located towards the front 10a of the working machine 10. The first and second storage tanks 26a, 26b each include a second end opposing the first end and located towards the rear 10b of the working machine 10. The second ends are vertically aligned (i.e. located the same distance from the rear 10b of the working machine 10), and the first end of the second storage tank 26b extends longitudinally beyond the first end of the first storage tank 26a. In some embodiments, the seconds ends are not vertically aligned, The second storage tank 26b extends along a majority of a longitudinal length of the working machine 10. The first storage tank 26a extends along approximately half, or less than half, of the longitudinal length of the working machine 10. It shall be appreciated that in alternative embodiments, the first and second storage tanks 26a, 26b may extend along any suitable length of the working machine 10. Each of the first and second storage tanks 26a, 26b define a longitudinal axis, and the longitudinal axes of the first and second storage tanks 26a, 26b are aligned with respect to a vertical plane extending parallel to the longitudinal axis a-a of the working machine 10. The prime mover 20 is located at the rear 10b of the working machine 10. Put another way, the prime mover 20 is located closer to the rear 10b than the front 10a of the working machine 10. As illustrated in Figure 2, the prime mover 20 is located in a rear third of the working machine 10 with respect to the longitudinal axis a-a. The prime mover 20 is located substantially centrally with respect to the transverse direction of the working machine 10. In particular, the prime mover 20 is located within the superstructure 16, i.e. housed within the engine housing 21. As illustrated in Figure 2, the prime mover 20 is located frontward of the counterweight 28. It shall be appreciated that in alternative embodiments, the prime mover 20 may be located at any suitable location on the working machine 10, for example rearward of the operator cab 22. In some embodiments, the prime mover 20 may be located in the undercarriage 12 of the working machine 10. An alternative embodiment in which the at least one storage tank 26c-g extends transversely with respect to the longitudinal axis a-a of the working machine 10 is illustrated in Figure 3 to 6. The storage tanks 26c-g shown in Figures 3 to 6 may therefore be referred to as transverse storage tanks 26c-g. In the embodiments of Figures 3 to 6, the gas engine 20 is longitudinally offset from the operator cab 22. The gas engine 20 is located substantially centrally with respect to the transverse direction (i.e. a centre of the gas engine 20 is equidistant from the first and second sides 10c, lOd). The gas engine 20 is housed within the superstructure 16, i.e. within the engine housing 21 in the interior volume 17. The gas engine 20 may be located in the undercarriage 12 of the working machine 10. In the embodiments illustrated in Figures 3 to 6, five transverse storage tanks 26c-g are provided. It shall be appreciated that in alternative embodiments, any suitable number of transverse storage tanks 26c-g may be provided, for example four transverse storage tanks or more than five transverse storage tanks. The transverse storage tanks may have a storage capacity of greater than 5kg, for example greater than 9kg, for example greater than 12kg . In the embodiment of Figures 3 and 4, the transverse storage tanks 26c-g are arranged on the superstructure 16 to be located in front of the gas engine 20. A majority of the transverse storage tanks 26c-g are located in front of the gas engine 20, for example an entirety of the transverse storage tanks 26c-g. The gas engine 20 is arranged between, for example interposed between, the transverse storage tanks 26c-g and the counterweight 28. As illustrated in Figure 4, the counterweight 28 includes a recessed front face 28a, and the gas engine 20 is arranged in the recessed front face 28a. This helps to provide a space efficient arrangement of the gas engine 20 and the storage tanks 26c-g. In the embodiment of Figures 5 and 6, the transverse storage tanks 26c-g are located towards the rear 10b of the working machine 10, and the gas engine 20 is located in front of the transverse storage tanks 26c-g. In particular, a majority of the gas engine 20, for example an entirety of the gas engine 20, is located in front of the transverse storage tanks 26c-g. The gas engine 20 is located between the transverse storage tanks 26c-g and the operator cab 22 when the working machine 10 is viewed in side view (i.e. in Figure 5). It shall be appreciated that although the transverse storage tanks 26c-g of Figures 3 and 4 are located in a different location with respect to the gas engine 20 to the embodiment of Figures 5 and 6, the transverse storage tanks 26c-g of Figures 3 and 4 are of substantially the same configured to the transverse storage tanks 26c-g of Figure 5 and 6. Accordingly, the teachings relating to the transverse storage tanks 26c-g are applicable to the embodiments of Figures 3 to 6. As illustrated in Figures 4 and 6, the transverse storage tanks 26c-g extend transversely across a majority of the working machine 10 with respect to the longitudinal axis a-a of the working machine 10. This helps to maximise storage capability of the transverse storage tanks 26c-g, and may improve weight distribution. It shall be appreciated that the transverse storage tanks 26c-g may not be able to occupy an entirety of the working machine 10. Instead, a clearance may be specified between the first and second sides 10c, lOd of the working machine 10 and the respective ends of the transverse storage tanks 26c-g. However, the transverse storage tanks 26c-g may occupy a maximum distance of the working machine 10 in the transverse direction whilst allowing for clearance for fitness and clearance from other components o the working machine 10. As such, the transverse storage tanks 26c-g may extend transversely across substantially an entirety of the working machine 10, where substantially an entirety includes extending across the maximum transverse distance of the working machine 10 possible whilst complying with the standard. The transverse storage tanks 26c-g are located substantially centrally with respect to the transverse direction of the working machine 10. Put another way, opposing first and second ends of the transverse storage tanks 26c-g are spaced apart equidistantly between the respective first and second sides 10c, lOd of the working machine 10, as illustrated in Figures 4 and 6. The plurality of transverse storage tanks 26c-g, for example the five storage tanks 26c-g illustrated in Figures 3 to 6, are arranged in a stacked configuration or stacked array. Longitudinal axis of each of the transverse storage tanks 26c-g extend substantially parallel. As illustrated in Figures 3 and 5, the stacked configuration may include an upper row including two transverse storage tanks 26c, 26d, a lower row including two transverse storage tanks 26f, 26g and an intermediate row located between the upper row and the lower row and including one transverse storage tank 26e. The transverse storage tank 26e of the intermediate row may be vertically offset from the transverse storage tanks 26c, 26d, 26f, 26g of the upper and / or lower rows. The transverse storage tanks 26c, 26d, 26f, 26g of the upper and lower rows may be vertically aligned. As such, the longitudinal axis of the transverse storage tank 26e of the intermediate row may be located equidistantly from the longitudinal axes of each of the transverse storage tanks 26c, 26d, 26f, 26g of the upper and lower rows. This arrangement helps to reduce a total height of the transverse storage tanks 26c-g. It shall be appreciated that the stacked configuration of Figures 3 to 6 is one of many possible arrangements of transverse storage tanks 26c-g. For example, the transverse storage tanks 26c-g may include the same number of storage tanks in each row, and include any suitable number of rows. The transverse storage tanks 26c-g occupy a majority of a height of the superstructure 16. This helps to increase the storage capacity of the transverse storage tanks 26c-g for a given footprint. An alternative embodiment of the at least one storage tank 26h-j is illustrated in Figures 7 to 10. It shall be appreciated that the embodiment of Figures 7 to 10 may be combined with any of the embodiments of Figures 1 to 6 in order to increase the storage capacity of the storage tanks 26a-g. The teachings described in relation to Figures 1 to 6 are therefore applicable to the embodiment of Figures 7 to 10. In Figures 7 to 10, the at least one storage tank 26h-j includes one or more tanks 26h-j mounted above the engine housing 21, for example in a tank housing 30 as will be described in more detail below. As such, the at least one storage tank 26h-j shown in Figures 7 to 10 may be referred to as housing storage tanks 26h-j. In the embodiment of Figures 7 to 10, the gas engine 20 is located within the engine housing 21 (i.e. within the superstructure 16), for example in any of the locations shown in Figures 1 to 6. Providing the housing storage tanks 26h-j above the engine housing 21 helps to prevent the one or more housing storage tanks 26h-j from obstructing components of the drive arrangement and hydraulic systems located within the engine housing 21. As illustrated in Figures 9 and 10, three housing storage tanks 26h-j are provided mounted above the engine housing 21. In particular, each of the housing storage tanks 26h-j is mounted to an uppermost surface 21a of the engine housing 21. The housing storage tanks 26h-j may have a storage capacity of greater than 5kg, for example greater than 9kg, for example greater than 12kg, for example greater than 15kg. It shall be appreciated that in alternative embodiments, any suitable number of housing storage tanks 26h-j may be provided, for example two housing storage tanks or four storage tanks. The housing storage tanks 26h-j each include a longitudinal axis, and the longitudinal axes of the housing storage tanks 26h-j extend transversely across the superstructure 16 with respect to the longitudinal axis a-a. The housing storage tanks 26h-j are provided in a longitudinally distributed array so as to be located side-by-side and extending in a common transverse direction relative to the longitudinal axis a-a of the working machine 10. The housing storage tanks 26h-j extend transversely across a majority of the superstructure 16 with respect to the longitudinal axis a-a. In particular, the housing storage tank 26h-j extends transversely across an entirety of the superstructure 16 with respect to the longitudinal axis a-a. In alternative embodiments, the housing storage tanks 26h-j may extend longitudinally (i.e. parallel to the longitudinal axis a-a) or diagonally with respect to the longitudinal axis a-a. The superstructure 16 includes the tank housing 30, illustrated in Figures 7 and 8, for housing the housing storage tanks 26h-j. As illustrated in Figure 7, the tank housing 30 is mounted to the uppermost surface 21a of the engine housing 21. The tank housing 30 is located rearward of the operator cab 22, for example immediately behind the operator cab 22. The tank housing 30 is located between the operator cab 22 and the counterweight 28. In particular, the tank housing 30 is located in front of the counterweight 28. In the embodiment of Figures 7 to 10, the tank housing 30 is located closer to the operator cab 22 than to the counterweight 28. The tank housing 30 does not extend beyond an uppermost extent of the operator cab 22. This helps to improve operator visibility. The tank housing 30 conforms to a shape of the housing storage tanks 26h-j, and is arranged in an orientation corresponding to that of the housing storage tanks 26h-j. As such, in the embodiment of Figures 7 to 10, the tank housing 30 extends transversely with respect to the longitudinal axis a-a of the working machine 10. The tank housing 30 is substantially rectangular in cross-section. In the embodiment of Figures 7 to 10, the tank housing 30 completely encloses the housing storage tanks 26h-j. This helps to provide protections to the housing storage tanks 26h-j. In alternative embodiments, the tank housing 30 may be a frame 30 and may form a protective cover over the housing storage tanks 26h-j without completely enclosing the housing storage tanks 26h-j. It shall be appreciated that in alternative embodiments, more than one tank housing may be provided to house one or more housing storage tanks 26h-j. The housing storage tanks 26h-j are mounted to the tank housing 30 via a mounting arrangement. The mounting arrangement may include anti-vibration mounts, or any alternative mounting arrangement may be used. The housing storage tanks 26h-j, tank housing 30 and pipework arrangement may be provided as a sub-assembly which is fitted to the working machine 10 as a unit. Figure 11 shows an alternative embodiment of the at least one storage tank 26k-n. It shall be appreciated that the embodiments of Figures 1 to 10 may be combined with the embodiment of Figure 11 in order to increase the storage capacity of the storage tanks 26a-n on the working machine 10. The teachings described in relation to Figures 1 to 10 are therefore applicable to the embodiment of Figure 11. The storage tanks 26k-m are mounted to the working arm 18. As such, the gas engine 20 may be located within the superstructure 16, for example in any of the locations illustrated in Figure 1 to 6. The storage tanks 26k-m are referred to as arm storage tanks 26k-m. Mounting the arm storage tanks 26k-m to the working arm 18 may be particularly advantageous because the superstructure 16 of a traditional diesel-powered working machine 10 may be used, with minimal alterations to accommodate the storage tanks 26k-m. The arm storage tanks 26k-m may be mounted within a cavity of the working arm 18 so as to provide protection to the arm storage tanks 26k-m. For example, the arm storage tanks 26k-m may be located within welded sections of the working arm 18. The arm storage tanks 26k-m are fixedly mounted to the working arm 18 such that the arm storage tanks 26k-m move with the working arm 18. The arm storage tanks 26k-m may be cylindrical storage tanks 26k-m. The arm storage tanks 26k-m may be mounted to the working arm 18 using a frame (not shown), or any alternative mounting arrangement. The mounting arrangement may include anti-vibration mounts. The arm storage tanks 26k-m include a first arm storage tank 26k mounted towards the first end of the working arm 18, and a second arm storage tank 261 mounted toward the second end of the working arm 18. In particular, the first and second arm storage tanks 26k, 261 are mounted to the boom 18a. The first arm storage tanks 26k is mounted to the boom 18a adjacent the pivotal connection 19, and the second arm storage tank 261 is mounted to the boom adjacent the dipper arm 18b. The boom 18a includes a first section extending from and connected to the pivotal connection 19 and a second section connected to the dipper arm 18b. The second section is angled with respect to the first section. The first arm storage tanks 26k is located on the first section and the second arm storage tank 261 is located on the second section. The first and second arm storage tanks 26k, 261 extend substantially parallel to the respective first or second section such that the second arm storage tank 261 extends at an angle with respect to the first arm storage tank 26k. The arm storage tanks 26k-m include a third arm storage tank 26m mounted to the dipper arm 18b. As such, the third arm storage tank 26m is moveable with respect to the first and second arm storage tanks 26k, 261. The third arm storage tank 26m extends substantially parallel to the dipper arm 18b. It shall be appreciated that in alternative embodiments, any suitable number of arm storage tanks 26k-m may be mounted to the working arm 18. In the embodiment of Figure 11, at least one storage tank 26a-o includes one or more storage tanks 26n, 26o mounted to the undercarriage 12. As such, the storage tanks 26n, 26o may be referred to as undercarriage storage tanks 26n, 26o. It shall be appreciated that although the arm storage tanks 26k-m are shown in combination with the undercarriage storage tanks 26n, 26o in Figure 11, the arm storage tanks 26k-m may be provided independently of the undercarriage storage tanks 26n, 26o and vice versa. The undercarriage storage tanks 26n, 26o are shown in plan view in Figure 13. In the embodiment shown in Figure 12, two undercarriage storage tanks 26n, 26o are shown mounted to the undercarriage 12. It shall be appreciated that in alternative embodiments, any suitable number of undercarriage storage tanks 26n, 26o may be provided. The undercarriage storage tanks 26n, 26o may have a storage capacity of greater than 5kg, for example greater than 9kg, for example greater than 12kg. Providing the undercarriage storage tanks 26n, 26o mounted to the undercarriage 12 provides a convenient location for storing hydrogen. The location of the undercarriage storage tanks 26n, 26o provide natural protection and does not interfere with operator visibility. The undercarriage storage tanks 26n, 26o may be mounted to the undercarriage 12 using any suitable mounting arrangement. The mounting arrangement may include anti-vibrations mounts. The undercarriage storage tanks 26n, 26o include a first undercarriage storage tank 26n extending longitudinally along a first side of the undercarriage 12, and a second undercarriage storage tank 26o extending longitudinally along an opposing second side of the undercarriage 12. As illustrated in Figure 11, the first of the pair of tracks 14a surrounds the first undercarriage tank 26n. It shall be appreciated that the second of the pair of tracks 14b may also surround the second undercarriage tank 26o. As illustrated in Figure 12, the undercarriage tanks 26n, 26o extend longitudinally with respect to a central longitudinal axis a-a o the working machine 10. Providing the undercarriage storage tanks 26n, 26o extending longitudinally may increase the storage capability of the track storage tanks 26n, 26o may increase the storage capability of the track storage tanks 26n, 26o by corresponding to the longest dimension of the undercarriage 12. The undercarriage storage tanks 26n, 26o are located substantially centrally with respect to an elongate length of the undercarriage 12. Put another way, front and rear ends of each of the storage tanks 26n, 26o are located substantially the same distance front the respective front 10a or rear 10b of the undercarriage 12. This arrangement may help to improve weight distribution of the undercarriage 12. The undercarriage 12 may be provided with gussets in which the undercarriage storage tanks 26n, 26o are located. In addition or alternatively, the rotary joint may be configured to allow hydrogen gas to pass therethrough. The rotary joint may be configured to allow hydrogen gas to pass therethrough in 360° rotation, for example in 360° infinite rotation. Figure 13 shows an alternative embodiment where the at least one storage tank includes a storage tank mounted to the undercarriage 12. It shall be appreciated that the embodiments of Figures 1 to 12 may be combined with the embodiment of Figure 13 in order to increase the storage capacity of the storage tanks 26a-o on the working machine 10. The teachings described in relation to Figures 1 to 12 are therefore applicable to the embodiment of Figure 13. In the embodiment of Figure 13, the storage tank extends through the rotary joint 23. As such, the storage tank may be referred to as a rotary joint storage tank. In particular, the rotary joint storage tank extends through the slew ring of the rotary joint 23. The rotary joint storage tank may extend substantially vertically (i.e. perpendicular to the longitudinal and transverse directions). The rotary joint storage tanks defines a longitudinal axis, and the longitudinal axis may be parallel or coaxial with an axis of rotation of the rotary joint 23. In the embodiment of Figure 13, one rotary joint storage tank is provided, however in alternative embodiments, any suitable number of rotary joint storage tanks may be provided. The storage capacity of the rotary joint storage tank may be greater than 5kg, for example greater than 9kg, for example greater than 12kg. Figure 14 shows an alternative embodiment of a working machine 110 according to the present teachings. Like parts with the embodiments of Figures 1 to 13 are labelled with the prefix "1". An alternative embodiment of the at least one storage tank 126a-d is illustrated in Figure 14. It shall be appreciated that the location of storage tanks 126a-d in the embodiments of Figures 1 to 13, where applicable, may be combined with the embodiment of Figure 14 in order to increase the storage capacity of the storage tanks 126a-d on the working machine 110. The teachings described in relation to Figures 1 to 13 are therefore applicable to the embodiment of Figure 14. In the embodiment shown in Figure 14, the working arm (not shown) is mounted to a front of the working machine 110. The working arm is mounted to the front of the working machine 110 via a pivotal connection 119. In particular, the working arm is mounted substantially centrally with respect to a central longitudinal axis of the working machine 110. The operator cab 122 may be located substantially centrally with respect to the central longitudinal axis of the working machine 110. It shall be appreciated that the teachings relating to Figure 14 are applicable to the working machines of Figures 1 to 13. The storage tanks 126a-d are mounted to the operator cab roof 122a. As such, the storage tanks 126a-d may be referred to as roof storage tanks 126a-d. The location of the roof storage tanks 126a-d provides potential for a large amount of gaseous storage, thereby extending the duration of use between refuelling operations. The gas engine is located within the superstructure 116, for example towards a rear of the working machine 110. The gas engine may be located underneath an operator seat. In this embodiment, four roof storage tanks 126a-d are provided. It shall be appreciated that in alternative embodiments, any suitable number of roof storage tanks 126a-d may be provided, for example two roof storage tanks, three roof storage tanks or five roof storage tanks. The roof storage tanks 126a-d may have a storage capacity of greater than 5kg, for example greater than 9kg, for example greater than 12kg. The roof storage tanks 126a-d are arranged longitudinally with respect to the longitudinal axis a-a of the working machine 110. In alternative embodiments, the roof storage tanks 126a-d may be arranged substantially transversely to the longitudinal axis a-a of the working machine 110. The roof storage tanks 126a-d occupy a majority of a surface area of the cab roof 122a. In the embodiment illustrated in Figure 14, the roof storage tanks 126a-d occupy an entirety of the surface area of the cab roof 122a. The roof storage tanks 126a-d may extend longitudinally beyond a front edge and / or a rear edge of the cab roof 122a. Put another way, the roof storage tanks 126a-d may be configured to overhang the front and / or rear of the operator cab 122 in order to increase the storage capacity of the roof storage tanks 126a-d or to reduce a height of the roof storage tanks 126a-d or a height of the working machine 110. An overhang may be greater in a rearward direction than a frontward direction, in order to improve operator visibility, for example when using the working arm (not shown). The extent of the overhang may be less than 10% of a length of the roof storage tanks 126a-d, however the overhang may be greater in some embodiments. The roof storage tanks 126a-d may extend laterally or transversely beyond a side edge of the cab roof 122a. Put another way, the roof storage tanks 126a-d may be configured to overhang one or both sides of the operator cab 122 in order to increase the storage capacity of the roof storage tanks 126a-d.The extent of the overhang may be less than 10% of a length of the roof storage tanks 126a-d, however the overhang may be greater in some embodiments. The cab roof 122a includes a mounting frame (not shown) to which the roof storage tanks 126a-d are mounted. The roof storage tanks 126a-d include an elongate cylinder having a neck portion at either end thereof, and the roof storage tanks 126a-d may be attached to the mounting frame via the neck portion. In some embodiments, a strap arrangement may be used to strap the roof storage tanks 126a-d to the cab roof 122a. The neck portions at either end may be received by suitable mounting features provided on the mounting frame. The tank neck portions may include relatively short cylindrical bosses which extend axially and concentrically with the longitudinal axis of the respective roof storage tanks 126a-d. Thus, the mounting frame may include first and second neck attachments for receiving the respective neck portions at either end of the roof storage tanks 126a-d. The mounting frame may include one or more mounting members for receiving storage tanks 126a-d and any suitable arrangement of structural members for distributing the weight of the roof storage tanks 126a-d across the operator cab 122. For example, the mounting frame may include a framework of cross-members which extend transverse to the longitudinal axes of the roof storage tanks 126a-d and a plurality of interconnected longitudinal members to provide sufficient strength and rigidity. The mounting frame may be mounted to the operator cab 122 via one or more attachment members which are attached to one or more structural members of the operator cab 122. The mounting frame and the roof storage tanks 126a-d and associated valves and gas lines may be provided as a sub-assembly for loading on the operator cab 122 as a single unit. In doing so, there is provided a convenient way of assembling and testing a gas storage system for the working machine 110 prior to mounting to the working machine 110. The mounting frame may be attached to the structural framework of the operator cab 122 so to provide sufficient support. It shall be appreciated that any suitable alternative arrangement may be used to mount the roof storage tanks 126a-d to the cab roof 122a. For example, an alternative method of attaching the roof storage tanks 126a-d to the operator cab 122 may be with the use of tank straps which extend circumferentially around the tanks. The one or more embodiments are described above by way of example only and it will be appreciated that the various aspects and features may be variously modified. For example, although principally aimed towards material handling machines such as excavators, the disclosure may apply to other forms of working machine. These variations are possible without departing from the scope of protection afforded by the appended claims. The one or more embodiments are described above by way of example only and it will be appreciated that the variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

1. A working machine comprising:an undercarriage mounted to a ground engaging structure;a superstructure rotatably mounted to the undercarriage;a working arm pivotally mounted to the superstructure;an operator cab mounted to the superstructure, wherein the operator cab is offset relative to a central longitudinal axis of the superstructure on a first side of the body;a prime mover, e.g. a gas engine, configured to provide motive power to the ground engaging structure; andat least one storage tank for supplying hydrogen to the prime mover, wherein the at least one storage tank comprises a first storage tank housed in the superstructure on a second side of the superstructure remote from the operator cab.

2. The working machine according to claim 1, comprising an access step arrangement located on the superstructure adjacent the operator cab, and wherein the first storage tank is at least partially arranged underneath the access step arrangement.

3. The working machine according to claim 1 or claim 2, wherein the at least one storage tank comprises the first storage tank and a second storage tank, and wherein the first storage tank is stacked vertically on top of the second storage tank.

4. The working machine according to claims 2 and 3, wherein the first storage tank is stacked vertically on top of the second storage tank underneath the access step arrangement.

5. The working machine according to claim 4, wherein the access step arrangement comprises at least two access steps, and wherein a first end of each of the first and second storage tanks is offset so as to conform to a shape of the access step arrangement.

6. The working machine according to claim 5, wherein the first and second storage tanks each comprise the first end located towards a front of the working machine and a second end located towards a rear of the working machine, and wherein thesecond ends are vertically aligned and the first end of the second storage tank extends longitudinally beyond the first end of the first storage tank.

7. The working machine according to any one of claims 3 to 6, wherein the second storage tank extends along a majority of the longitudinal length of the working machine.

8. The working machine according to any preceding claim, wherein the first storage tank is arranged substantially parallel to a central longitudinal axis of the working machine.

9. The working machine according to any preceding claim, comprising a pivotal connection configured to pivotally mount the working arm to the superstructure, and wherein the pivotal connection is located adjacent the at least one storage tank, optionally wherein the pivotal connection is interposed between the operator cab and the first storage tank.

10. A working machine comprising:an undercarriage mounted to a ground engaging structure;a superstructure rotatably mounted to the undercarriage;a working arm pivotally mounted to the superstructure;a prime mover, e.g. a gas engine, configured to provide motive power to the ground engaging structure;wherein the working machine defines a front and a rear, and the prime mover is located at or towards the rear of the working machine; andat least one storage tank for supplying hydrogen to the prime mover, wherein the at least one storage tank comprises one or more transverse tanks extending transversely with respect to a longitudinal axis of the working machine.11.The working machine according to claim 10, wherein the one or more transverse tanks extend transversely across a majority of the working machine with respect to the longitudinal axis of the working machine.12.The working machine according to claim 10 or claim 11, wherein the one or more transverse storage tanks comprises a plurality of transverse storage tanks, optionally wherein the plurality of transverse storage tanks are arranged in a stacked configuration.13.The working machine according to claim 12, wherein the plurality of transverse storage tanks occupy a majority of a height of the superstructure.14.The working machine according to any one of claim 10 to claim 13, wherein the one or more transverse tanks are arranged on the superstructure to be located in front of the prime mover.15.The working machine according to claim 14, comprising a counterweight mounted to a rear of the superstructure, wherein the prime mover is arranged between, for example interposed between, the one or more transverse tanks and the counterweight.16.The working machine according to claim 15, wherein the counterweight has a recessed front face, and the prime mover is arranged in the recess.17.The working machine according to any one of claim 10 to claim 13, wherein the one or more transverse tanks are located towards a rear of the working machine, and wherein the prime mover is located in front of the one or more transverse tanks, optionally wherein an entirety of the prime mover is located in front of the one or more transverse tanks.18.The working machine according to claim 17, comprising an operator cab mounted to the superstructure, wherein the prime mover is located between the one or more transverse storage tanks and the operator cab when the working machine is viewed in side view.

19. A working machine comprising:an undercarriage mounted to a ground engaging structure;a superstructure rotatably mounted to the undercarriage;a working arm pivotally mounted to the superstructure;a prime mover, e.g. a gas engine, configured to provide motive power to the ground engaging structure;wherein the superstructure comprises a prime mover housing for housing the prime mover; andat least one storage tank for supplying hydrogen to the prime mover, wherein the at least one storage tank comprises one or more housing storage tanks mounted above the prime mover housing.20.The working machine according to claim 19, wherein the superstructure comprises a tank housing for housing the one or more housing storage tanks, and wherein the tank housing is mounted to an uppermost surface of the prime mover housing.21.The working machine according to claim 19 or claim 20, wherein the one or more housing storage tank is located rearward of the operator cab.22.The working machine according to any one of claim 19 to claim 21, wherein the one or more housing tanks do not extend beyond an uppermost extent of the operator cab.23.The working machine according to any one of claim 19 to claim 22, wherein the working machine comprises a longitudinal axis, and wherein the one or more housing tanks extend transversely across the superstructure with respect to the longitudinal axis.24.The working machine according to claim 23, wherein the one or more housing storage tanks extend transversely across a majority of the superstructure with respect to the longitudinal axis, optionally wherein the one or more housing storage tanks extend transversely across substantially an entirety of the superstructure with respect to the longitudinal axis.25.The working machine according to any preceding claim, wherein the working machine is an excavator.Application No:     GB2410291.5Examiner: Damien HuxleyClaims searched: 1 to 25Date of search: 5 November 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1, 3 &25 GB2615333 A (J. C. BAMFORD EXCAVATORS LIMITED) See the whole document A KR101179617B1 (HWANG) See the figures and the English language translation available from Google Patents at: httDs: / / Datents.gooele.com / Datent / KR101179617Bl / en?oq=KR10117961 7B1Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From B60K 0015 / 07 01 / 01 / 2006 B60K 0015 / 03 01 / 01 / 2006 B60K 0015 / 063 01 / 01 / 2006 B60K 0015 / 067 01 / 01 / 2006Application No:     GB2410291.5Examiner: Damien HuxleyClaims searched: 10 to 18 (& 25 in part)Date of search: 3 March 2025Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance v A X 10 to 13, 17, 18 &25 10 to 13, 17, 18 &25 GB2615333 A (J.C. BAMFORD EXCAVATORS LIMITED) See the text from line 24 of page 1 to line 21 of page 2, lines 1 to 35 of pare 21 and the figures KR101179617B1 (HWANG SEONG JO) See the figures and the English language translation available from Google Patents at: httDs: / / Datents.google.com / oatent / KR101179617Bl / en?oq=KR10117961 7B1Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From B60K 0015 / 07 01 / 01 / 2006 B60K 0015 / 03 01 / 01 / 2006 B60K 0015 / 063 01 / 01 / 2006 B60K 0015 / 067 01 / 01 / 2006Application No:     GB2410291.5Examiner: Damien HuxleyClaims searched: 19 to 24 (& 25 in part) Date of search: 3 March 2025Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance A GB2615333 A (J.C. BAMFORD EXCAVATORS LIMITED) See the text from line 24 of page 1 to line 21 of page 2, lines 1 to 35 of pare 21 and the figures A KR101179617B1 (HWANG SEONG JO) See the figures and the English language translation available from Google Patents at: httDs: / / Datents.google.com / patent / KR101179617Bl / en?oq=KR10117961 7B1 A WO2024 / 143326 Al (KUBOTA CORPORATION) See the figures and the English language translation available from Google Patents at: httDs: / / Datents.google.com / natent / W02024143326Al / en?oq=W020241 43326Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP. WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC____________ B60K___________________________________________________ The following online and other databases have been used in the preparation of this search report WPI, EPODOCInternational Classification:Subclass Subgroup Valid From B60K 0015 / 07 01 / 01 / 2006 B60K 0015 / 03 01 / 01 / 2006Subclass Subgroup Valid From B60K 0015 / 063 01 / 01 / 2006 B60K 0015 / 067 01 / 01 / 2006

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