Patent Description:
A typical braking system for a machine includes a hydraulic circuit with valves fluidly connected to service brakes, which, when actuated, decelerate the machine. A pedal may be manually actuated by an operator to control one or more valves to increase the fluid pressure supplied to the brakes such that the brakes are actuated. Alternatively, a control system may control one or more additional valves to implement an automatic braking mode such as auto retarding, anti-skid braking or dynamic brake control. A brake system implementing both operator and automatic braking may have relatively increased costs, increased space requirements and high complexity of design due to the need for multiple valves for the automatic braking mode and multiple hydraulic and electrical lines for those valves.

<CIT>) discloses a hydraulic braking system comprising first and second brake valves acting upon first and second brake circuits. The first and second brake valves are arranged in a parallel configuration and are operable together by a foot pedal and individually by pilot pressure from respective, first and second control valves responsive to first and second control signals from an engine control unit.

The present invention provides a brake system comprising a control system, an operator input device and a plurality of brakes, and a brake valve assembly. The brake valve assembly comprising at least one channel including an operator brake valve controllable by the operator input device, an automatic brake valve controllable by the control system, and a control valve fluidly connected to at least one brake of the plurality of brakes and the operator and automatic brake valves. The control valve is configurable by the control system between an operator brake configuration for fluidly connecting the operator brake valve to the at least one brake and an automatic brake configuration for fluidly connecting the automatic brake valve to the at least one brake. The brake valve assembly is configurable in: an operator braking mode in which the control valve is in the operator brake configuration and the at least one brake is controllable by the operator brake valve in response to an input to the operator input device; and an automatic braking mode in which the control valve is in the automatic brake configuration and the at least one brake is controllable by the automatic brake valve in response to a control signal from the control system.

The present invention further provides a machine comprising such a brake system.

The present invention provides a method of operating a brake system, the brake system comprising a control system, an operator input device and a plurality of brakes, and a brake valve assembly comprising at least one channel. The at least one channel comprising an operator brake valve, an automatic brake valve and a control valve fluidly connected to at least one brake of the plurality of brakes and the operator and automatic brake valves. The method comprises determining, by the control system, whether to implement an operator braking mode or an automatic braking mode, and implementing the operator braking mode by: maintaining the control valve in an operator brake configuration to fluidly connect the operator brake valve to the at least one brake and receiving an input at the operator input device to control the operator brake valve and thereby control the at least one brake; or implementing the automatic braking mode by maintaining the control valve in an automatic brake configuration to fluidly connect the automatic brake valve to the at least one brake and automatically controlling, by the control system, the automatic brake valve and thereby control the at least one brake.

The present invention is described in conjunction with the appended figures.

In the appended figures, similar components and/or features may have the same reference label.

The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the invention.

Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that embodiments may be practised without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. A process is terminated when its operations are completed, but could have additional steps not included in the figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function. Moreover, as disclosed herein, the term "storage medium" may represent one or more devices for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices and/or other machine readable mediums for storing information. The term "computer-readable medium" includes, but is not limited to portable or fixed storage devices, optical storage devices, wireless channels and various other mediums capable of storing, containing or carrying instruction(s) and/or data.

Furthermore, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium such as storage medium. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc..

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present invention may repeat reference numerals and/or letters in the various examples. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

The present invention is generally directed towards a brake system for a machine. The brake system comprises a brake valve assembly comprising at least one channel, each channel comprising an operator brake valve, an automatic valve and a control valve. In each channel the control valve is fluidly connected to the automatic valve and operator brake valve. The control valve is controlled by a control system between operator and automatic brake configurations, which fluidly connect the operator or automatic brake valve respectively to at least one brake. The brake valve assembly is configurable in operator and automatic braking modes by changing the configuration of the control valve between the operator and automatic brake configurations respectively.

In the operator braking mode the operator can manually control the at least one brake by providing an input to an operator input device, which controls the operator brake valve and thus pressurised fluid supply to the at least one brake. In the automatic braking mode the control system automatically controls the at least one brake by providing a control signal to the automatic brake valve, which controls the pressurised fluid supply to the at least one brake. The control valve in each channel may enable the automatic control of the at least one brake independently of the operator input. The automatic control can thus override the operator input and advanced braking features, such as anti-lock braking, can be implemented.

<FIG> schematically illustrates a machine <NUM> comprising a brake system <NUM> in accordance with the present invention. <FIG> schematically illustrates a further machine <NUM> and brake system <NUM> of the present invention. <FIG> and <FIG> illustrate the same features with the same reference numerals.

The machine <NUM> may comprise wheels <NUM> driven by a power unit or engine (not illustrated) for enabling the machine <NUM> to travel over a terrain. The machine <NUM> may comprise tracks or the like driven by the wheels <NUM> and may be independently moveable across the terrain rather than on any rails or the like. The machine <NUM> may comprise a tractor unit attached to a trailer, which may comprise a tipping body. The tractor and trailer units may each comprise at least one pair of wheels <NUM>. The machine <NUM> may therefore comprise an articulated hauler, wheel loader or motor grader. However, the machine <NUM> may be a work machine and may be a hauling machine, such as a dump truck, on-highway truck or off-highway truck, and/or an earth-moving or material handling machine, such as a backhoe, wheel tractor scraper, loader, dozer, shovel, drilling machine, motor grader, forestry machine or excavator.

The brake system <NUM> comprises a plurality of brakes <NUM>, <NUM>, <NUM>, <NUM>, a control system <NUM>, an operator input device <NUM> and a brake valve assembly <NUM>. The brake system <NUM> may comprise a fluid system <NUM> comprising the brake valve assembly <NUM> fluidly connected to the brakes <NUM>, <NUM>, <NUM>, <NUM>. The control system <NUM> and operator input device <NUM> are configured to selectively control the brake valve assembly <NUM> to control the application of the brakes <NUM>, <NUM>, <NUM>, <NUM>. In particular, the brake valve assembly <NUM> may control the transfer of pressurised hydraulic fluid to the at least one brake <NUM>, <NUM>, <NUM>, <NUM> for selective actuation thereof.

In the present invention, the term "fluidly connected" means that components are connected by fluid lines (illustrated as lines in <FIG> and <FIG>) and ports such that fluid can be transferred between the components. The fluid may be hydraulic fluid, which may be substantially incompressible, and may be maintained under pressure by at least one fluid source <NUM>, <NUM>, such as at least one accumulator and/or hydraulic pump (discussed further below). In the present invention the brake valve assembly <NUM> is for distributing fluid pressure to the respective components of the brake system <NUM> and, as is known in the art, may not include a circulating flow of pressurised fluid. Terms relating to the control, flow, communication, transfer or the like of the fluid may instead refer to the control of the application of fluid pressure in which there may be little or no flow of the pressurised fluid, for example, by means of directional control valves.

The brakes <NUM>, <NUM>, <NUM>, <NUM> may be configured to selectively apply a braking force to the wheels <NUM> to decelerate and/or control the angular velocity of the wheels <NUM>. The brakes <NUM>, <NUM>, <NUM>, <NUM> may be hydraulic brakes, friction brakes and/or service brakes. The brakes <NUM>, <NUM>, <NUM>, <NUM> may comprise four brakes <NUM>, <NUM>, <NUM>, <NUM>, each associated with a wheel <NUM>, as illustrated in <FIG> and <FIG>.

The operator input device <NUM> may be operably connected to and be for actuating the brake valve assembly <NUM>. The operator input device <NUM> may be a manual input device and may require a manual input from an operator in order to actuate the brake valve assembly <NUM>. The operator input device <NUM> may comprise a foot pedal, treadle and/or hand operated lever and may be operably connected to the brake valve assembly <NUM> by a mechanical connection as illustrated in <FIG>. Alternatively, the operator input device <NUM> may be operably connected to the brake valve assembly <NUM> by the control system <NUM> or another electrical system. The operator input device <NUM> may alternatively comprise a lever, a button, a touch screen or the like.

The brake valve assembly <NUM> comprises at least one channel <NUM>, <NUM>, <NUM>, <NUM>, each comprising an operator brake valve <NUM>, <NUM>, <NUM>, <NUM>, an automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> and a control valve <NUM>, <NUM>, <NUM>, <NUM> fluidly connected to the operator and automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. The at least one channel <NUM>, <NUM>, <NUM>, <NUM>, particularly the control valve <NUM>, <NUM>, <NUM>, <NUM> thereof, controls and is in fluid communication with at least one of the brakes <NUM>, <NUM>, <NUM>, <NUM>.

<FIG> illustrates a two channel brake system <NUM> in accordance with the present invention. The brake valve assembly <NUM> may comprise at least two channels <NUM>, <NUM>, <NUM>, <NUM> and may comprise first and second channels <NUM>, <NUM>. The first channel <NUM> comprises a first operator brake valve <NUM>, a first automatic brake valve <NUM> and a first control valve <NUM> fluidly connected to the first operator brake valve <NUM> and first automatic brake valve <NUM>. The second channel <NUM> comprises a second operator brake valve <NUM>, a second automatic brake valve <NUM> and a second control valve <NUM> fluidly connected to the second operator brake valve <NUM> and the second automatic brake valve <NUM>.

<FIG> illustrates a four channel brake system <NUM> in accordance with the present invention.

The brake system <NUM> of <FIG> comprises first and second channels <NUM>, <NUM> in a similar manner to the brake system <NUM> of <FIG>. In <FIG> the brake valve assembly <NUM> further comprises a third channel <NUM> comprising a third operator brake valve <NUM>, a third automatic brake valve <NUM> and a third control valve <NUM> fluidly connected to the third operator brake valve <NUM> and third automatic brake valve <NUM>. In <FIG> the brake valve assembly <NUM> further comprises a fourth channel <NUM> comprising a fourth operator brake valve <NUM>, a fourth automatic brake valve <NUM> and a fourth control valve <NUM> fluidly connected to the fourth operator brake valve <NUM> and fourth automatic brake valve <NUM>. Each channel <NUM>, <NUM>, <NUM>, <NUM> controls and is fluidly connected to at least one of the plurality of brakes <NUM>, <NUM>, <NUM>, <NUM>. As in <FIG>, the or each channel <NUM>, <NUM> may be fluidly connected to at least two brakes <NUM>, <NUM>, <NUM>, <NUM>. In particular, the first channel <NUM> and first control valve <NUM> may control and be in fluid communication with at least one, or two as illustrated, first brakes <NUM>, <NUM>. The second channel <NUM> and second control valve <NUM> may control and be in fluid communication with the at least one, or two as illustrated, second brakes <NUM>, <NUM>. Alternatively, as in <FIG>, each channel <NUM>, <NUM>, <NUM>, <NUM> may be fluidly connected to one brake <NUM>, <NUM>, <NUM>, <NUM>. In particular, the first, second, third and fourth channels <NUM>, <NUM>, <NUM>, <NUM> and respective first, second, third and fourth control valves <NUM>, <NUM>, <NUM>, <NUM> may control and be in fluid communication with the respective the first, second, third and fourth brakes <NUM>, <NUM>, <NUM>, <NUM>. Although not illustrated, the brake system <NUM> may comprise channels <NUM>, <NUM>, <NUM>, <NUM> in fluid communication with different numbers of brakes <NUM>, <NUM>, <NUM>, <NUM>. For example, one or more channels <NUM>, <NUM>, <NUM>, <NUM> may be fluidly connected to one brake <NUM>, <NUM>, <NUM>, <NUM> and one or more other channels <NUM>, <NUM>, <NUM>, <NUM> may be fluidly connected to at least two brakes <NUM>, <NUM>, <NUM>, <NUM>.

The fluid system <NUM> may comprise at least one fluid source <NUM>, <NUM> for supplying hydraulic fluid to the brake valve assembly <NUM> and/or at least one of the brakes <NUM>, <NUM>, <NUM>, <NUM>. The at least one fluid source <NUM>, <NUM> may comprise separate, first and second tanks or accumulators <NUM>, <NUM> as shown, each storing and supplying pressurised fluid to the rest of the fluid system <NUM>. The at least one fluid source <NUM>, <NUM> may be fluidly connected to, and supply pressurised fluid to, the operator brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> and automatic brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> as illustrated in <FIG> and <FIG>.

The fluid system <NUM> may comprise a fluid drain <NUM> for receiving hydraulic fluid from the brake valve assembly <NUM>, for example from leak lines as illustrated. The fluid drain <NUM> may be fluidly connected to the at least one fluid source <NUM>, <NUM>, for example by a further hydraulic circuit (not illustrated), for recirculating fluid back through the brake valve assembly <NUM>. The fluid drain <NUM> may be fluidly connected to, and receive fluid from, the operator brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> and automatic brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> as illustrated in <FIG> and <FIG>. The fluid drain <NUM> may also be fluidly connected to the operator brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> and/or operator input device <NUM> by a check valve <NUM> such that fluid exiting at the connection between the operator brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> and operator input device <NUM> can return to the fluid drain <NUM>.

The following disclosure generally describes an operator brake valve <NUM>, <NUM>, <NUM>, <NUM>, an automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> and a control valve <NUM>, <NUM>, <NUM>, <NUM> of one channel <NUM>, <NUM>, <NUM>, <NUM>. However, as discussed above, the brake system <NUM> may comprise at least two channels <NUM>, <NUM>, <NUM>, <NUM> and each channel <NUM>, <NUM>, <NUM>, <NUM> may include the same features and functionality. As a result, the following description may be read to describe the operator brake valve <NUM>, <NUM>, <NUM>, <NUM>, automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> and control valve <NUM>, <NUM>, <NUM>, <NUM> of each channel <NUM>, <NUM>, <NUM>, <NUM>.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> is operably connected to and controllable by the operator input device <NUM>. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be in fluid communication with the at least one fluid source <NUM>, <NUM>, the fluid drain <NUM> and/or a control valve <NUM>, <NUM>, <NUM>, <NUM> and may be configured to direct fluid therebetween.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may comprise a pressure inlet <NUM> connected to the at least one fluid source <NUM>, <NUM> for receiving fluid therefrom, a leak outlet <NUM> connected to the fluid drain <NUM> for supplying excess fluid thereto and/or a control port <NUM> for supplying pressurised fluid to the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. For the sake of clarity reference numerals indicating the features of only the first operator brake valve <NUM> are illustrated in <FIG>, although the other operator brake valve <NUM>, <NUM>, <NUM> may comprise the same features as illustrated.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be actuated by, and may be directly responsive to, an input by an operator of the machine <NUM> to the operator input device <NUM>. As illustrated in <FIG>, the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be responsive to an input in the form of actuation of a foot pedal <NUM> by an operator of the machine <NUM>. Actuation of the foot pedal <NUM> may compress springs <NUM>, which may actuate the operator brake valve <NUM>, <NUM>, <NUM>, <NUM>. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may alternatively be responsive to an input or braking signal by other suitable mechanisms, such as a solenoid actuated by an engine control unit in response to an operator pressing a brake pedal.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configurable or actuatable between a first operator brake valve position <NUM>, a second operator brake valve position <NUM> and/or a third operator brake valve position <NUM>, for example by actuation of a valve slide therein. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may comprise a <NUM>-way <NUM>-position valve. Alternatively, the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may only be configurable in the first and third operator brake valve positions <NUM>, <NUM> and the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may comprise a <NUM>-way <NUM>-position valve.

The first operator brake valve position <NUM> may be for applying the at least one brake <NUM>, <NUM>, <NUM>, <NUM> attached to the channel <NUM>, <NUM>, <NUM>, <NUM> of the operator brake valve <NUM>, <NUM>, <NUM>, <NUM>. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured in the first operator brake valve position <NUM> in response to an input to the operator input device <NUM> and when the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is in the process of being applied. In the first operator brake valve position <NUM> pressurised fluid may be communicated by the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> to the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>, for example from the at least one fluid source <NUM>, <NUM> as illustrated. In particular, the pressure inlet <NUM> may be fluidly connected to the control port <NUM> to allow pressurised fluid to communicate therethrough.

The second operator brake valve position <NUM> may also be for applying the at least one brake <NUM>, <NUM>, <NUM>, <NUM> attached to the channel <NUM>, <NUM>, <NUM>, <NUM> of the operator brake valve <NUM>, <NUM>, <NUM>, <NUM>. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured into the second operator brake valve position <NUM> when the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is applied. The second operator brake valve position <NUM> may be configured to hold the at least one brake <NUM>, <NUM>, <NUM>, <NUM> in an applied state. In the second operator brake valve position <NUM> fluid may not be communicated through the operator brake valve <NUM>, <NUM>, <NUM>, <NUM>, for example by the pressure inlet <NUM>, leak outlet <NUM> and control port <NUM> of each operator brake valve <NUM>, <NUM>, <NUM>, <NUM> being fluidly disconnected with one another.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured into the third operator brake valve positions <NUM> when no application of the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is demanded by the operator. In the third operator brake valve position <NUM> fluid may be communicated from the control valve <NUM>, <NUM>, <NUM>, <NUM> to the fluid drain <NUM>, for example by the control port <NUM> being in fluid communication with the leak outlet <NUM>. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be biased from the first operator brake valve position <NUM> towards the third operator brake valve position <NUM>.

The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be a load-sensing valve, which may provide a smoother operator experience of the application of the brakes <NUM>, <NUM>, <NUM>, <NUM>. An orifice <NUM> may be provided at the control port <NUM> and may be provided internally to the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> to provide such load-sensing functionality.

If the brake valve assembly <NUM> comprises a plurality of channels <NUM>, <NUM>, <NUM>, <NUM>, the operator brake valves <NUM>, <NUM>, <NUM>, <NUM> may be arranged in a parallel configuration as illustrated. The operator brake valves <NUM>, <NUM>, <NUM>, <NUM> may control a plurality of the brakes <NUM>, <NUM>, <NUM>, <NUM>, optionally all of the brakes <NUM>, <NUM>, <NUM>, <NUM> simultaneously and the brake valve assembly <NUM> may be configured such that the operator brake valves <NUM>, <NUM>, <NUM>, <NUM> cannot control individual brakes <NUM>,<NUM>, <NUM>, <NUM> independently. An input to the operator input device <NUM> may actuate the operator brake valves <NUM>, <NUM>, <NUM>, <NUM> simultaneously such that all operator brake valves <NUM>, <NUM>, <NUM>, <NUM> move to the first and/or second operator brake valve position <NUM>, <NUM> and pressurised fluid is supplied via the control valves <NUM>, <NUM>, <NUM>, <NUM> to the brakes <NUM>, <NUM>, <NUM>, <NUM>.

The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> is operably connected to and controllable by the control system <NUM>. The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> is in fluid communication with the at least one fluid source <NUM>, <NUM>, the fluid drain <NUM> and/or control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM> and may be configured to direct fluid therebetween.

The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may comprise a pressure inlet <NUM> connected to the at least one fluid source <NUM>, <NUM> for receiving fluid therefrom, a leak outlet <NUM> connected to the fluid drain <NUM> for supplying excess fluid thereto and/or a control port <NUM> for supplying pressurised fluid to the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. For the sake of clarity, reference numerals indicating the features of only the first automatic brake valve <NUM> are illustrated in <FIG>, although the other automatic brake valves <NUM>, <NUM>, <NUM> may comprise the same features as illustrated.

The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> is actuated by, and is directly responsive to, a control or braking signal from the control system <NUM>. If the brake valve assembly <NUM> comprises a plurality of channels <NUM>, <NUM>, <NUM>, <NUM>, the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> of each channel <NUM>, <NUM>, <NUM>, <NUM> may be independently controllable such that each channel <NUM>, <NUM>, <NUM>, <NUM> can independently control the at least one brake <NUM>, <NUM>, <NUM>, <NUM> they are fluidly connected to.

The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configurable or actuatable between a variable control configuration <NUM> and an off configuration <NUM>, for example by actuation of a valve slide therein. The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may comprise an adjustable, solenoid, proportional and/or <NUM>-way <NUM>-position valve. The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may be biased towards the off configuration <NUM>.

The variable control configuration <NUM> may be for applying the at least one brake <NUM>, <NUM>, <NUM>, <NUM> and the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured in the variable control configuration <NUM> in response to an electrical braking signal from the control system <NUM>. In the variable control configuration <NUM>, pressurised fluid may be communicated by the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> to the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>, for example from the at least one fluid source <NUM>, <NUM> as illustrated. In particular, the pressure inlet <NUM> may be fluidly connected to the control port <NUM> to allow pressurised fluid to communicate therethrough.

The automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured into the off configuration <NUM> when no application of the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is demanded by the control system <NUM>. In the off configuration <NUM> fluid may be communicated from the or each control valve <NUM>, <NUM>, <NUM>, <NUM> to the fluid drain <NUM>, for example by the control port <NUM> being in fluid communication with the leak outlet <NUM>, as illustrated. Alternatively, in the off configuration <NUM> the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> may not communicate fluid therethrough.

The control valve <NUM>, <NUM>, <NUM>, <NUM> is operably connected to and controllable by the control system <NUM>. The control valve <NUM>, <NUM>, <NUM>, <NUM> is fluidly connected to the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> and the automatic brake valve <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. The control valve <NUM>, <NUM>, <NUM>, <NUM> is configured to control whether the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> or the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM> is fluidly connected with at least one brake <NUM>, <NUM>, <NUM>, <NUM> associated with the channel <NUM>, <NUM>, <NUM>, <NUM>. The control valve <NUM>, <NUM>, <NUM>, <NUM> may be actuated by, and may be directly responsive to, a control signal from the control system <NUM>.

The control valve <NUM>, <NUM>, <NUM>, <NUM> may comprise a first control valve port <NUM> fluidly connected to the respective operator brake valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>, a second control valve port <NUM> fluidly connected to the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM> and a third control valve port <NUM> fluidly connected to at least one brake <NUM>, <NUM>, <NUM>, <NUM>. For the sake of clarity, reference numerals indicating the features of only the first control valve <NUM> are illustrated in <FIG>, although the other control valves <NUM>, <NUM>, <NUM> may comprise the same features as illustrated.

The control valve <NUM>, <NUM>, <NUM>, <NUM> is controllable by the control system <NUM> between an operator brake configuration <NUM> and an automatic brake configuration <NUM>, for example by actuation of a valve slide therein. The control valve <NUM>, <NUM>, <NUM>, <NUM> may comprise may comprise an adjustable, solenoid, proportional, on-off and/or <NUM>-way <NUM>-position valve. The control valve <NUM>, <NUM>, <NUM>, <NUM> may be biased towards the operator brake configuration <NUM>. The control valve <NUM>, <NUM>, <NUM>, <NUM> may only be configurable in the operator and automatic brake configurations <NUM>, <NUM> and in no other configurations.

In the operator brake configuration <NUM>, the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> is fluidly connected with the at least one brake <NUM>, <NUM>, <NUM>, <NUM> via the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. Thus the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is controllable by the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> in response to an input to the operator input device <NUM>. The first control valve port <NUM> may be fluidly connected to the third control valve port <NUM>.

In the automatic brake configuration <NUM>, the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> is fluidly connected with the at least one brake <NUM>, <NUM>, <NUM>, <NUM> via the control valve <NUM>, <NUM>, <NUM>, <NUM> of the same channel <NUM>, <NUM>, <NUM>, <NUM>. The at least one brake <NUM>, <NUM>, <NUM>, <NUM> is controllable by the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> in response to a control signal from the control system <NUM>. The second control valve port <NUM> may be fluidly connected to the third control valve port <NUM>.

The control system <NUM> is configured to control the control and automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in order to control the brakes <NUM>, <NUM>, <NUM>, <NUM>. The control system <NUM> may comprise a controller communicatively connected (via a wired or wireless connection) to the control and automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The controller may be of any suitable known type and the control system <NUM> may be an engine control unit (ECU), part of an ECU or independent of an ECU. The controller may comprise a storage medium, which may store instructions or algorithms in the form of data, and a processing unit, which may be configured to perform operations based upon the instructions. The storage medium may comprise any suitable computer-accessible or non-transitory storage medium for storing computer program instructions, such as RAM, SDRAM, DDR SDRAM, RDRAM, SRAM, ROM, magnetic media, optical media and the like. The processing unit may comprise any suitable processor capable of executing memory-stored instructions, such as a microprocessor, uniprocessor, a multiprocessor and the like. The controller may further comprise a graphics processing unit for rendering objects for viewing on a display.

The control system <NUM> may comprise at least one input and at least one sensor communicatively connected (via a wired or wireless connection) to the controller. The at least one input may comprise a user interface, switch, touch screen, button or the like. The at least one sensor may comprise a wheel speed sensor, a position sensor associated with the operator input device <NUM> and/or an engine speed sensor and may be for sensing a machine speed, actuation of the operator input device <NUM>, a machine engine speed and/or other operational parameters. The controller may be configured to receive data from the at least one input and/or at least one sensor and perform operations based upon instructions stored in the storage medium. The controller may generate and send signals, such as the control and/or braking signals, to the control and/or automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The control system <NUM> may automatically control the control and/or automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, by sending control signals thereto, in accordance with at least one advanced braking routine. Each advanced braking routine may be stored as instructions on the controller storage medium. The advanced braking routine may comprise auto retarding, electronic brake application, an anti-lock braking system (ABS) or anti-skid braking, dynamic stability control (DSC) or the like. Each advanced braking routine may at least partially controllable by an input from the operator to the at least one input (for example an input by an operator turning ABS on or off), but once implemented by the control system <NUM> the advanced braking routine may control the control and automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> independently of the operator.

The brake system <NUM>, and particularly the or each at least one channel <NUM>, <NUM>, <NUM>, <NUM>, is configurable in an operator braking mode <NUM> in which the control valve <NUM>, <NUM>, <NUM>, <NUM> is in the operator brake configuration <NUM> and the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is controllable by the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> in response to an input to the operator input device <NUM>. The brake system <NUM> is also configurable an automatic braking mode <NUM> in which the control valve <NUM>, <NUM>, <NUM>, <NUM> is in the automatic brake configuration <NUM> and the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is controllable by the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> in response to a control signal from the control system <NUM>. To swap between the operator and automatic braking modes <NUM>, <NUM>, the control system <NUM> actuates the control valve <NUM>, <NUM>, <NUM>, <NUM> between the operator brake configuration <NUM> and the automatic brake configuration <NUM> respectively.

An exemplary method <NUM> of operating the brake system <NUM> in accordance with the present invention is illustrated in <FIG>. The following description of the method <NUM> is in reference to the implementation of the operator and automatic braking modes <NUM>, <NUM> in one channel <NUM>, <NUM>, <NUM>, <NUM>.

In a determination step <NUM>, it is determined, for example at the control system <NUM>, whether to implement an operator braking mode <NUM> or an automatic braking mode <NUM>. The control system <NUM> may implement the automatic braking mode <NUM> if it determines that at least one advanced braking routine is required. The control system <NUM> may determine that an advanced braking routine is required based upon data received from the at least one input and/or at least one sensor. For example, the control system <NUM> may receive data from a wheel speed sensor showing that one or more wheels <NUM> have locked and thereby determine that anti-skid braking is required. The operator braking mode <NUM> may be implemented if the control system <NUM> does not determine that an advanced braking routine is required.

In the operator braking mode <NUM> the operator may selectively actuate the at least one brake <NUM>, <NUM>, <NUM>, <NUM> for slowing the wheels <NUM> and machine <NUM>. At step <NUM>, the operator braking mode <NUM> is implemented by maintaining the control valve <NUM>, <NUM>, <NUM>, <NUM> in the operator brake configuration <NUM> to fluidly connect the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> to the at least one brake <NUM>, <NUM>, <NUM>, <NUM>. For example, the control valve <NUM>, <NUM>, <NUM>, <NUM> may be biased to the operator brake configuration <NUM>. The operator braking mode <NUM> may be implemented unless the control system <NUM> actuates the control valve <NUM>, <NUM>, <NUM>, <NUM>.

At step <NUM> the operator provides an input to the operator input device <NUM>, such as by pressing on the foot pedal <NUM>. At step <NUM> the operator input device <NUM> controls the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> to actuate or control the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, such as by controlling the flow of pressurised fluid thereto. The operator input device <NUM> may actuate the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> by virtue of the operable connection therebetween and the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may move to the first operator brake valve position <NUM>. As a result, pressurised fluid may be transferred from the at least one fluid source <NUM>, <NUM> and may be transferred to the control valve <NUM>, <NUM> and onto the at least one brake <NUM>, <NUM>, <NUM>, <NUM>. Thus the at least one brake <NUM>, <NUM>, <NUM>, <NUM> may be applied. The pressure in first operator brake valve position <NUM> may vary in accordance with the input to the operator input device <NUM> (e.g. the travel of the foot pedal <NUM>), thereby controlling the fluid pressure at the at least one brake <NUM>, <NUM>, <NUM>, <NUM> such that applied braking force can also be varied. The operator input device <NUM> may actuate the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> by virtue of the operable connection therebetween and the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may move from the first operator brake valve position <NUM> to the second operator brake valve position <NUM> such that the at least one brake <NUM>, <NUM>, <NUM>, <NUM> may be held in an applied state.

If the operator does not provide an input to the operator input device <NUM> at step <NUM>, then at step <NUM> the at least one brake <NUM>, <NUM>, <NUM>, <NUM> may not be actuated. The operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may be configured, such as by being biased, into the third operator brake valve position <NUM>. Pressurised fluid may not be transferred to the at least one brake <NUM>, <NUM>, <NUM>, <NUM> from the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> such that the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is not actuated. Instead, in the third operator brake valve position <NUM>, fluid may return to the fluid drain <NUM> such that the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is not applied.

In the automatic braking mode <NUM> the control system <NUM> may selectively actuate the at least one brake <NUM>, <NUM>, <NUM>, <NUM> for slowing the wheels <NUM> and machine <NUM>. At step <NUM>, the automatic braking mode <NUM> is implemented by maintaining the control valve <NUM>, <NUM>, <NUM>, <NUM> in the automatic brake configuration <NUM> to fluidly connect the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> to the at least one brake <NUM>, <NUM>, <NUM>, <NUM>. The control system <NUM> may actuate the control valve <NUM>, <NUM>, <NUM>, <NUM> into the automatic brake configuration <NUM>.

At step <NUM>, the control system <NUM> may determine whether to control the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> to actuate the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, for example based upon at least one advanced braking routine. At step <NUM>, the control system <NUM> automatically controls the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM>. The control system <NUM> may actuate the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> into the variable control configuration <NUM>. As a result, pressurised fluid may be transferred from the at least one fluid source <NUM>, <NUM> and may be transferred to the control valve <NUM>, <NUM>, <NUM>, <NUM> and onto the at least one brake <NUM>, <NUM>, <NUM>, <NUM>. Thus the at least one brake <NUM>, <NUM>, <NUM>, <NUM> may be applied.

The control system <NUM> may adjust the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> in accordance with an advanced braking routine. The control system <NUM> may adjust the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> in the variable control configuration <NUM> to vary the fluid pressure and thereby vary the braking force applied by the brakes <NUM>, <NUM>, <NUM>, <NUM>.

If at step <NUM> the control system <NUM> determines to not actuate the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, then at step <NUM> the control system <NUM> may actuate the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> into the off configuration <NUM>, or allow the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> to be biased into the off configuration <NUM>, such that fluid may return to the fluid drain <NUM> and the at least one brake <NUM>, <NUM>, <NUM>, <NUM> is not applied.

The control system <NUM> may implement the automatic braking mode <NUM> whilst the brake system <NUM> is in the operator braking mode <NUM> and an input is being received from the operator at the operator input device <NUM>. Therefore, the control system <NUM> may be configured to override the operator input and control the at least one brake <NUM>, <NUM>, <NUM>, <NUM> independently of the operator and in accordance with an advanced braking routine.

The method <NUM> described above with reference to <FIG> may be implemented in a plurality of channels <NUM>, <NUM>, <NUM>, <NUM>. In the determination step <NUM>, it may determined, for example at the control system <NUM>, whether to implement an operator braking mode <NUM> or an automatic braking mode <NUM> in one or more of the channels <NUM>, <NUM>, <NUM>, <NUM>. Subsequently, the operator or automatic braking modes <NUM>, <NUM> may be implemented in all of the channels <NUM>, <NUM>, <NUM>, <NUM>.

When a plurality of channels <NUM>, <NUM>, <NUM>, <NUM> are operated in the automatic braking mode <NUM>, the control system <NUM> may control (for example adjust the fluid pressure through or prevent fluid pressure through) the automatic brake valves <NUM>, <NUM>, <NUM>, <NUM> independently of each other. Therefore, the control system <NUM> may be operable to control the brakes <NUM>, <NUM>, <NUM>, <NUM> independently of one another. As a result, when a plurality of channels <NUM>, <NUM>, <NUM>, <NUM> are operated in the automatic braking mode <NUM>, different advanced braking routines may be implemented for different brakes <NUM>, <NUM>, <NUM>, <NUM>.

Alternatively, in the determination step <NUM> the control system <NUM> may determine that least one wheel <NUM> needs to be controlled by the operator and least one other wheel <NUM> by the control system <NUM>. The control system <NUM> may control the control valves <NUM>, <NUM>, <NUM>, <NUM> independently of one another. The operator braking mode <NUM> may be implemented in one or more channels <NUM>, <NUM>, <NUM>, <NUM> and the automatic braking mode <NUM> may be implemented in one or more other channels <NUM>, <NUM>, <NUM>, <NUM>. The operator may thus still have some control of the brakes <NUM>, <NUM>, <NUM>, <NUM> and the control system <NUM> may be able to implement an advanced braking routine in respect of only one or some of the brakes <NUM>, <NUM>, <NUM>, <NUM>. For example, if only one wheel <NUM> skids, anti-skid braking can be implemented only in respect of the associated brake <NUM>, <NUM>, <NUM>, <NUM>.

In a particular unclaimed aspect of the present disclosure, the advanced braking routine may be an anti-skid braking routine and method <NUM> may be implemented as follows. The plurality of channels <NUM>, <NUM>, <NUM>, <NUM> may be operated in the operator braking mode <NUM>. At determination step <NUM>, the control system <NUM> may determine that at least one wheel <NUM> associated with at least one brake <NUM>, <NUM>, <NUM>, <NUM> has locked and the machine <NUM> may be skidding, for example based upon data deceived from a wheel speed sensor attached to the at least one wheel <NUM>.

At step <NUM>, the control system <NUM> may subsequently implement the automatic braking mode <NUM>, overriding the operator braking mode <NUM>, for all channels <NUM>, <NUM>, <NUM>, <NUM> or for at least the channel <NUM>, <NUM>, <NUM>, <NUM> fluidly connected to the at least one brake <NUM>, <NUM>, <NUM>, <NUM> associated with the at least one locked wheel <NUM>. The control system <NUM> may implement the automatic braking mode <NUM> by actuating the control valve(s) <NUM>, <NUM>, <NUM>, <NUM> to the automatic brake configuration <NUM>.

At step <NUM>, the control system <NUM> may determine that an advanced braking routine, particularly an anti-skid braking routine, should be implemented in all channels <NUM>, <NUM>, <NUM>, <NUM> or in at least the channel <NUM>, <NUM>, <NUM>, <NUM> fluidly connected to the at least one brake <NUM>, <NUM>, <NUM>, <NUM> associated with the at least one locked wheel <NUM>. As a result, at step <NUM> the control system <NUM> automatically controls the relevant automatic brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> in accordance with the anti-skid braking routine. For example, the control system <NUM> may control the automatic brake valve(s) <NUM>, <NUM>, <NUM>, <NUM> in the variable control configuration <NUM> and may control the fluid pressure supplied to, to control the braking force applied by, the at least one brake <NUM>, <NUM>, <NUM>, <NUM> associated with the at least one locked wheel <NUM> such that the wheel <NUM> is unlocked and able to rotate. The control system <NUM> may control the automatic brake valve <NUM>, <NUM>, <NUM>, <NUM> in the variable control configuration <NUM> and control the braking force applied by, the at least one brake <NUM>, <NUM>, <NUM>, <NUM> until the machine <NUM> comes to a halt.

The brake system <NUM> may be applicable to machines <NUM> where braking is required to be controlled manually and directly by the operator and also automatically and independently of the operator. The brake system <NUM> may reduce the number of valves required, and may thereby reduce manufacturing costs and may increase reliability due to requiring fewer components.

In particular, the same control valve <NUM>, <NUM>, <NUM>, <NUM> may be used to implement either the advanced braking routine or direct manual control by an operator. This may result in a significant cost reduction and much better machine integration.

The implementation of the control valve <NUM>, <NUM>, <NUM>, <NUM> may allow advanced braking features such as an anti-lock braking routine to be used. For an anti-lock braking routine, the input from the operator through the operator brake valve <NUM>, <NUM>, <NUM>, <NUM> may need to be blocked and the control valve <NUM>, <NUM>, <NUM>, <NUM> may allow this. In prior art designs, advanced braking features such as an anti-lock braking routine may not be implementable because the operator input may not be overridable.

The brake system <NUM> may also be modular in design by virtue of the ability to add or remove further channels <NUM>, <NUM>, <NUM>, <NUM> from the brake valve assembly <NUM>. Therefore, the brake system <NUM> may be effectively designed for and implemented in a wide variety of machines <NUM>.

By having multiple channels <NUM>, <NUM>, <NUM>, <NUM> with separate control, operator and automatic brake valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, the redundancy of the brake system <NUM> may be significantly increased. In particular, should failure in one channel <NUM>, <NUM>, <NUM>, <NUM> occur then it will not affect the braking ability of the other channel(s) <NUM>, <NUM>, <NUM>, <NUM>.

Claim 1:
A brake system (<NUM>) comprising:
a control system (<NUM>), an operator input device (<NUM>) and a plurality of brakes (<NUM>, <NUM>, <NUM>, <NUM>); and
a brake valve assembly (<NUM>) comprising at least one channel (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
an operator brake valve (<NUM>, <NUM>, <NUM>, <NUM>) controllable by the operator input device; and
an automatic brake valve (<NUM>, <NUM>, <NUM>, <NUM>) controllable by the control system (<NUM>);
characterised by a control valve (<NUM>, <NUM>, <NUM>, <NUM>) fluidly connected to at least one brake of the plurality of brakes (<NUM>, <NUM>, <NUM>, <NUM>) and the operator and automatic brake valves (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the control valve (<NUM>, <NUM>, <NUM>, <NUM>) is configurable by the control system (<NUM>) between an operator brake configuration for fluidly connecting the operator brake valve (<NUM>, <NUM>, <NUM>, <NUM>) to the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>) and an automatic brake configuration for fluidly connecting the automatic brake valve (<NUM>, <NUM>, <NUM>, <NUM>) to the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>);
wherein the brake valve assembly (<NUM>) is configurable in:
an operator braking mode in which the control valve (<NUM>, <NUM>, <NUM>, <NUM>) is in the operator brake configuration and the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>) is controllable by the operator brake valve (<NUM>, <NUM>, <NUM>, <NUM>) in response to an input to the operator input device (<NUM>); and
an automatic braking mode in which the control valve (<NUM>, <NUM>, <NUM>, <NUM>) is in the automatic brake configuration and the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>) is controllable by the automatic brake valve (<NUM>, <NUM>, <NUM>, <NUM>) in response to a control signal from the control system (<NUM>).