Abstract: An electro-hydraulic steering system comprises a hydraulic steering actuator and a hydro-mechanical steering unit for actuating the hydraulic steering actuator in response to a steering demand. An electronically controllable steering supply valve arrangement is able to supply fluid to the actuator independently of or in combination with hydro-mechanical steering unit. The hydro-mechanical steering unit is specified to provide a maximum volume flow rate of fluid to the actuator which is above that required to provide an emergency steering function but is less than that required for full steering functionality under normal operating conditions. In normal use, the steering supply valve arrangement is used to amplify the fluid flow from the hydro-mechanical steering unit to ensure full steering capability. In an emergency steering situation, the hydro-mechanical steering unit is able to provide sufficient fluid flow to maintain a limited steering capability.

Abstract: A control system for hydraulic supply system on a tractor includes an electronic load sensing (E-LS) system. The control system is configured to limit the pump supply pressure PSP so that the load sensing pressure LSP reported by at least one valve (CMV, RMV, IMV) does not exceed a pre-defined upper limit of LSP assigned to that valve. Since the LSP reported by a valve is indicative of the pressure at a working port of the valve, monitoring the LSP and limiting the PSP in dependence on LSP can be used to ensure the pressure at the working port does not exceed a permitted value. In an embodiment, the system monitors pressure signals indicative of LSP from a number of valves whilst increasing the PSP to meet a hydraulic demand and stops increasing the PSP if the LSP of any of the valves exceeds a respective pre-defined upper limit.

Abstract: A system for controlling a hydraulic supply on a mobile machine comprises electronic load sensing and is configured to enter a predictive mode of control in which the pump supply pressure PSP is increased following a determination that a hydraulic consumer has been actuated irrespective of the reported hydraulic load at the time. The control system is arranged to monitor the load sensing pressure while operative in a predictive mode of control and to revert to a load-sensing-based control of the pump supply in dependence on the value and/or rate of change of the load sensing pressure. A corresponding method of controlling a hydraulic system on a mobile machine is also disclosed.

Abstract: A mobile machine such as a tractor has an engine and hydraulic supply system including a pump supply with a pump (MP) driven by the engine to provide a pressurized fluid at a pump supply pressure PSP. The hydraulic supply system has an electronic load sensing system (E-LS) to regulate the pump supply pressure. The E-LS is arranged to increase a stand-by pressure differential of the pump supply once the engine is determined to be running following start-up. This enables the hydraulic supply system to be configured with a reduced hydro-mechanically defined stand-by pressure differential so that it places a reduced load on the engine when it is started. The E-LS may be arranged to inhibit LS control of the pump supply when the engine is started, with LS functionality only commenced once the engine is running. Reduced load on the engine during start-up can improve cold starting.

Abstract: A mobile machine such as a tractor has an engine and hydraulic supply system including a pump supply with a pump (MP) driven by the engine to provide a pressurized fluid at a pump supply pressure PSP. The hydraulic supply system has an electronic load sensing system (E-LS) to regulate the pump supply pressure. The E-LS is arranged to increase a stand-by pressure differential of the pump supply once the engine is determined to be running following start-up. This enables the hydraulic supply system to be configured with a reduced hydro-mechanically defined stand-by pressure differential so that it places a reduced load on the engine when it is started. The E-LS may be arranged to inhibit LS control of the pump supply when the engine is started, with LS functionality only commenced once the engine is running. Reduced load on the engine during start-up can improve cold starting.

Abstract: An assembly system for components of a pressurized fluid supply system for an agricultural vehicle includes a body having at least one fluid duct connectable at one end to a pressurized fluid supply and having a socket at the other end. A detachable component such as an accumulator or oil filter is connectable in releasable mechanical engagement with the body to receive pressurized fluid from the at least one fluid duct. The engagement results from insertion of at least a portion of the component into the socket and rotation of the component to a locked position. The body has at least one discharge duct extending therethrough. In a partially rotated position of the component portion within the socket, the component remains mechanically attached to the body and the fluid duct and discharge duct are in fluidic connection, discharging accumulated pressure in the fluid duct.

Abstract: An assembly system for components of a pressurized fluid supply system for an agricultural vehicle includes a body having at least one fluid duct connectable at one end to a pressurized fluid supply and having a socket at the other end. A detachable component such as an accumulator or oil filter is connectable in releasable mechanical engagement with the body to receive pressurized fluid from the at least one fluid duct. The engagement results from insertion of at least a portion of the component into the socket and rotation of the component to a locked position. The body has at least one discharge duct extending therethrough. In a partially rotated position of the component portion within the socket, the component remains mechanically attached to the body and the fluid duct and discharge duct are in fluidic connection, discharging accumulated pressure in the fluid duct.

Abstract: A method of manufacturing cracker roller discs comprises forming a disc blanks and machining to produce the final form. The disc blank has an axial bore through the centre, a first portion radially outward of the centre of substantially constant thickness, a second portion radially outward of the first portion which second portion tapers towards the periphery of the disc blank, and a plurality of upstanding ridges extending radially outward across the second portion on opposed faces of the disc. Machining, suitably by turning on a lathe, removes the top part of each ridge and leaves at least one sharp edge extending along it, with all ridges on a face being machined in a single operation.

Abstract: A pressurised fluid supply system for an agricultural vehicle (100) includes a main supply circuit (MC) including a variable displacement pump (RP) providing a first source of pressurised fluid to a steering system (SS) of the vehicle and to consumers (WH) connected with the vehicle. A steering supply circuit (SC) includes a fixed displacement pump (LHP) supplying pressurised fluid to the steering system (SS). A pilot pressure circuit (PPC), connectable to supply a second source of pressurised fluid to consumers connected with the vehicle, receives pressurised fluid from the main supply circuit (MC).