Cut-to-length logging harvester vehicle and harvester head, and operating method for a cut-to-length logging harvester vehicle

Abstract

The invention relates to a cut-to-length logging harvester vehicle (100), comprising: a vehicle frame (110) having a propulsion arrangement, a harvester head (130) having a bar saw (140) operable in a log-cutting mode, said bar saw (140) having a saw bar (142), a saw chain (144), and a saw bar positioner (146) configured to control a position of the bar saw, a log-feeding device (160) operable in a log-feeding mode; and a first hydraulic actuator (150) configured to mechanically drive the saw chain (142); an articulated crane (120) connected at its base side to the vehicle frame and connected at its tip side to the harvester head (130); a first hydraulic pump (180) arranged at the base side and configured, when in the log-cutting mode, to control a speed of the saw chain (142) towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, F1, to the first hydraulic actuator (150) via a first hydraulic conduit (190) extending between the base side and the tip side; wherein the speed of the saw chain has, when in the log-cutting mode, a proportional dependency on the regulated first hydraulic flow, F1.

Description

[0001] CUT-TO-LENGTH LOGGING HARVESTER VEHICLE AND HARVESTER

[0002] HEAD, AND OPERATING METHOD FOR A CUT-TO-LENGTH LOGGING

[0003] HARVESTER VEHICLE

[0004] Field of the invention

[0005] The present invention relates to a cut-to-length logging harvester vehicle, cut-to-length logging harvester head, and an operating method for a cut-to-length logging harvester vehicle.

[0006] Technical background

[0007] Cut-to-length forestry vehicles are an important part in modern forestry operations, performing the tasks of felling, delimbing, and bucking trees into predetermined lengths. Despite their advanced capabilities, several challenges persist in optimizing their operation, particularly concerning energy efficiency.

[0008] Forestry operations demand high levels of power and precision, typically provided by hydraulic systems that drive various components of cut- to-length logging harvester vehicles, for example saws, delimbing knives, and components for controlling the harvester head and the crane. However, these hydraulic systems often suffer from significant energy losses. For example, frictional losses within the hydraulic lines, heat generation during fluid compression and expansion, and leakage all contribute to reduced energy efficiency. These inefficiencies not only increase fuel consumption but also limit the overall operational productivity of the forestry vehicle.

[0009] There is still a strong need to address these issues to improve the performance of cut-to-length logging harvester vehicles. Innovations aimed at reducing hydraulic energy losses, optimizing energy recovery mechanisms, optimizing the design and usage of the hydraulic systems, and improving the control of hydraulic actuators can lead to substantial

[0010] General - No protection improvements in the energy efficiency and effectiveness of forestry operations. Consequently, there remains a significant need for advancements in hydraulic system design and control within the field of forestry vehicles.

[0011] Summary

[0012] It would be advantageous to provide cut-to-length logging harvester vehicle, cut-to-length logging harvester head and an operating method for a harvester vehicle, that at least is alleviating some of the above- mentioned drawbacks. To better address one or more of these concerns a cut-to-length logging harvester vehicle, a cut-to-length logging harvester head and a cut-to-length logging harvester vehicle operating method are presented. Preferred embodiments of the harvester vehicle, the harvester head and the method are defined in the dependent claims.

[0013] Hence, according to a first aspect of the present invention, there is provided a cut-to-length logging harvester vehicle, comprising: a vehicle frame having a propulsion arrangement and a harvester head. The harvester head comprises a bar saw operable in a log-cutting mode, said bar saw having a saw bar, a saw chain, and a saw bar positioner configured to control a position of the bar saw. The harvester head further comprises a log-feeding device operable in a log-feeding mode and a first hydraulic actuator configured to mechanically drive the saw chain. The cut-to-length logging harvester vehicle further comprises an articulated crane connected at its base side to the vehicle frame and connected at its tip side to the harvester head. The cut-to-length logging harvester vehicle further comprises a first hydraulic pump arranged at the base side and configured, when in the log-cutting mode, to control a speed of the saw chain towards a predetermined logcutting speed by outputting a regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit extending between the base side and the tip side. Further, the speed of the saw chain has, when in the

[0014] General - No protection log-cutting mode, a proportional dependency on the regulated first hydraulic flow, F1.

[0015] According to a second aspect of the present invention a cut-to- length logging harvester head is provided. The cut-to-length logging harvester head comprises a bar saw operable in a log-cutting mode, said bar saw having a saw bar, a saw chain, a saw bar positioner configured to control a position of the bar saw. The cut-to-length logging harvester head further comprises a log-feeding device operable in a log-feeding mode, a first hydraulic actuator arranged to receive a regulated first hydraulic flow, F1 , via a first hydraulic conduit and configured, when the bar saw is in log-cutting mode, to mechanically drive the saw chain by the regulated first hydraulic flow, F1 , a first hydraulic interface configured to connect to a cut-to-length logging harvester vehicle and to receive the regulated first hydraulic flow from a first hydraulic pump, wherein a speed of the saw chain has, when in the logcutting mode, a proportional dependency on the first flow.

[0016] The cut-to-length logging harvester head is adapted to be part of the cut-to-length logging harvester vehicle as discussed in the first aspect of the present invention. The first and second hydraulic interface may be referred to as the initial point of connection between a hydraulic system of a harvester vehicle, such as the cut-to-length logging harvester vehicle as discussed in the first aspect of the present invention, and the hydraulic mechanisms within the harvester head. The first hydraulic interface may be configured to transfer hydraulic power from the vehicle's hydraulic system to the components in the harvester head, enabling their operation. The hydraulic interface may be configured to be an engagement site, e.g., for a tube / hose forming part of the first hydraulic conduit or a tube / hose forming part of the second hydraulic conduit as previously discussed.

[0017] According to a third aspect of the present invention a cut-to- length logging harvester vehicle operating method is provided. The cut-to- length logging harvester vehicle comprises a vehicle frame comprising a propulsion arrangement, a cut-to-length logging harvester head having a bar

[0018] General - No protection saw operable in a log-cutting mode, said bar saw having a saw bar, a saw chain, and a saw bar positioner configured to control a position of the bar saw. The cut-to-length logging harvester head further comprises a log-feeding device operable in a log-feeding mode, and a first hydraulic actuator configured to mechanically drive the saw chain, cut-to-length logging harvester vehicle further comprises an articulated crane connected at its base side to the vehicle frame and connected at its tip side to the harvester head, a first hydraulic pump arranged at the base side and configured, when in the log-cutting mode, to control a speed of the saw chain towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit extending between the base side and the tip side, and at least one second hydraulic actuator configured to mechanically drive the log-feeding device. The method comprises operating the cut-to-length logging harvester vehicle in the logcutting mode or the log-feeding mode, wherein in the log-cutting mode the following is performed: controlling a speed of the saw chain by the first hydraulic pump via the regulated first hydraulic flow, F1 , based on a proportional dependency on the regulated first flow towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, F1 , by the first hydraulic pump, and providing, the regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit to drive the saw chain.

[0019] Thus, the present invention is based on the common concept or idea of providing a cut-to-length solution that provides an improved design and / or control of one or more parts of the cut-to-length system / methodology. The present invention allows control of a speed of the saw chain using a first hydraulic pump, configured to control a speed of the saw chain towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, such that the speed of the saw chain has a proportional dependency on the regulated first hydraulic flow. This removes the need for mechanical throttling

[0020] General - No protection means, such as valves, to control the flow and thereby the saw chain speed, which in turn reduces heat losses and improves energy efficiency.

[0021] Accordingly, the present invention is advantageous in that outputting a regulated first hydraulic flow, F1 , may be performed on the base side, e.g., on the vehicle frame. In other words, regulating the first hydraulic flow may be performed on the base side / vehicle side, i.e. , not on the tip side / crane side. Hence, it is to be understood that the cut-to-length logging harvester vehicle may be configured to regulate the output of the first hydraulic flow, F1 , on the base side. In other words, the cut-to-length logging harvester vehicle is configured to regulate the regulated first hydraulic flow on the base side, e.g., on the vehicle / vehicle frame.

[0022] It will be appreciated that the cut-to-length logging harvester vehicle allows direct control of the saw chain by controlling the generation of the hydraulic flow driving the chain. In other words, the speed of the saw chain may be controlled based on a proportional dependency between the hydraulic flow generation of the first hydraulic pump and the speed of the saw chain. A proportional dependency between the hydraulic flow generated by the first hydraulic pump and the speed of the saw chain means that as the hydraulic pump increases its flow rate, the speed of the saw chain increases correspondingly. Conversely, reducing the pump's flow rate decreases the saw chain's speed. The saw chain speed is directly linked to the amount of hydraulic fluid supplied by the pump.

[0023] It will be further appreciated that the present inventions allows controlling of the speed of the saw chain in an improved manner without using valves, e.g., throttle valves. This results in improved energy efficiency, since a common problem of regulating flows with valves is the heat losses that occur, e.g., during throttling.

[0024] It will be further appreciated that the present invention allows a more energy efficient control of a speed of a saw chain while still providing precise control of the speed of the saw chain.

[0025] General - No protection

[0026] The articulated crane may have one boom / segment, or multiple booms / segments connected at pivot points, allowing it to extend, retract, and bend in various directions. The articulated crane, and one or more of its functions, may be powered by hydraulic systems and / or electric systems. An articulated crane may perform precise lifting and placement tasks.

[0027] The vehicle frame is a structural foundation of a vehicle, providing support and stability. It serves as the foundation to which other components, such as the engine, transmission, suspension, wheels, and the crane, are attached. The frame should be strong enough to handle the stresses and loads encountered during operation, ensuring safety and performance. There are various types of vehicle frames, including ladder frames, unibody frames, and space frames, each designed to meet specific requirements of different vehicles. In this case, the vehicle frame may be a cut-to-length logging harvester vehicle frame capable of handling the stress of driving and operating in rough terrain.

[0028] The harvester head comprises a bar saw with a saw chain, and a first hydraulic actuator configured to mechanically drive the saw chain. The bar saw, and hence the first hydraulic actuator, is operable in a log-cutting mode. A bar saw may comprise a bar, e.g., long and flat, that guides a saw chain with sharp teeth. The bar saw may be driven by an actuator that in turn may be powered by a hydraulic flow generated by a pump / motor, and / or may be powered by an electric machine and / or motor. The bar saw may be used in forestry, logging and woodworking for tasks such as felling trees and cutting logs. The bar saw may be referred to as a chain saw.

[0029] By “log-cutting mode” it is here meant an operating mode for cutting logs, i.e. , a mode in which the saw chain is running and configured for cutting a tree. In an example, during the “log-cutting mode” a log may be held in place relative the harvester head such that the place of the cut may be controlled. Further, the bar saw, or the bar of the bar saw, may be configured to move relative the log, e.g., in a plane going through a log held in the harvester head, such that the saw chain guided by the bar may cut through

[0030] General - No protection the log during log-cutting mode. The log-feeding device may be configured to move / position the log to / at a desired cutting position, and may at least partially hold the log in the cutting position during log-cutting mode.

[0031] The harvester head further comprises a log-feeding device, and at least one second hydraulic actuator configured to mechanically drive the log-feeding device. The log feeding device is operable in a log-feeding mode.

[0032] By “log-feeding mode” it is here meant an operating mode for feeding logs, i.e. , a mode in which no cutting is performed and the first hydraulic actuator driving the saw chain may be unpowered. In the logfeeding mode, the harvester head holds and feeds / moves the log to be cut to a position, relative the bar saw, where it is to be cut.

[0033] The log-feeding device may be a device / apparatus / mechanism that can grip and move the log through the harvester head for processing and / or positioning. It may drive the log forward or backward, allowing the harvester head to cut, delimb, and / or measure the log accurately and efficiently.

[0034] The cut-to-length logging harvester vehicle further comprises a first hydraulic pump arranged in the vehicle frame. A hydraulic pump may be any device capable of creating a flow in a hydraulic liquid, suitable for driving actuators on a harvester vehicle, such as a bar saw. The pump is configured to drive the saw chain by feeding a first a hydraulic flow to the first hydraulic actuator via a first hydraulic conduit. A hydraulic conduit may be a passage or channel, such as a pipe, hose, or tube, through which hydraulic fluid flows to transmit power within a hydraulic system. For example, from a pump to an actuator.

[0035] The first hydraulic pump is configured to control a speed of the saw chain by the first hydraulic flow, and is configured during log-cutting mode to drive the saw chain exclusively. By driving exclusively during logcutting mode, it is here meant that the pump, i.e., the hydraulic flow it generates, only drives the saw chain, and no other actuators or consumers. It

[0036] General - No protection is to be understood that the first hydraulic actuator exclusively drives the saw chain of the bar saw.

[0037] The log-feeding device, during-log feeding mode, is powered by at least one of the first hydraulic pump and a hydraulic power unit. The hydraulic power unit may be a self-contained system that includes one or more hydraulic system components, to control / provide / generate fluid flow and pressure. It may generate and supply hydraulic power to drive hydraulic machinery and equipment. The hydraulic power unit may convert e.g. mechanical energy into hydraulic energy, enabling the operation of hydraulic cylinders, motors, and / or other hydraulic actuators.

[0038] The hydraulic power unit is configured to, if the log-feeding device is in log-feeding mode, to power the log-feeding device, by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit.

[0039] Throughout the application, the term “harvester vehicle” may be interchangeably used with “cut-to-length logging harvester vehicle”. Note that this is for conciseness, and not to diminish the meaning of a cut-to-length logging harvester vehicle, which is different from other harvester vehicles such as feller-bunchers, while-tree chippers and skidders. Similarly, the term “harvester head” may be interchangeably used with “cut-to-length logging harvester head”.

[0040] In an embodiment of the present invention, the cut-to-length logging harvester vehicle, when in the log-cutting mode, is configured to convey the regulated first hydraulic flow, F1 , unthrottled from the first hydraulic pump to the first hydraulic actuator. Here, "convey" refers to the process of moving or transporting hydraulic fluid from one part of the system to another. This typically involves the use of pumps, conduits / hoses, and valves to direct the flow of fluid, enabling the transfer of energy to actuate components such as cylinders, motors, or other hydraulic devices. Conveying

[0041] General - No protection fluid in a hydraulic system in an unthrottled manner means that the hydraulic fluid flows freely without restriction or pressure control by adjustable throttles, such as valves. By conveying the first flow unthrottled from the first hydraulic pump to the first hydraulic actuator, the fluid may be transferred directly through conduits / pipes / hoses, allowing it to move at its natural generated pressure and flow rate, resulting in reduced energy loss and more efficient operation.

[0042] In an embodiment of the present invention, the harvester head comprises at least one second hydraulic actuator configured to mechanically drive the log-feeding device, and wherein the log-feeding device, when in the log-feeding mode, is powered by at least one of the first hydraulic pump and a hydraulic power unit, wherein the hydraulic power unit is configured, when in log-feeding mode, to power the log-feeding device, by outputting a second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit. Hence, the cut-to-length logging harvester vehicle may comprise a second hydraulic actuator, different from the first hydraulic actuator, which is configured to drive the log-feeding device. The second hydraulic actuator may be powered by the first hydraulic pump in the logfeeding mode. The cut-to-length logging harvester vehicle may be configured such that the first hydraulic pump power the first hydraulic actuator in logcutting mode, and power the second hydraulic actuator in the log-feeding mode. It is to be understood that powering an actuator with a pump means that the hydraulic pump supplies pressurized hydraulic fluid to the actuator, i.e. the pump generates the necessary pressure and / or flow rate, while the actuator uses this pressure to create motion or force. The present embodiment is advantageous in that different functions of the harvester vehicle may be powered by different components / pumps / power units depending on the operating requirements, such that in one situation the first hydraulic pump may be used to drive the saw chain in log-cutting mode, and power the log-feeding device in log-feeding mode, and in another situation the

[0043] General - No protection log-feeding device may be powered by a hydraulic power unit and not the first hydraulic pump. Hence, the present embodiment provides an increased versatility and adaptability. Furthermore, the present embodiment may provide increased energy efficiency, since it may be more efficient to use the first hydraulic pump and its flow generation capabilities in one scenario, and the hydraulic power unit and its flow generation capabilities in another scenario, wherein the flow generation capabilities are different for the first hydraulic pump and the hydraulic power unit.

[0044] In an embodiment of the present invention, the hydraulic power unit comprises a second hydraulic pump arranged at the base side, and wherein the harvester head comprises at least one of: a harvester head rotator, harvester head clamps, and a harvester head filter. The at least one second hydraulic actuator is configured to mechanically drive at least one of the harvester head rotator, the harvester head clamp means, the harvester head filter, and the saw bar positioner. The second hydraulic pump is configured, when in log-cutting mode, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head filter and the saw bar positioner by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit extending between the base side and the tip side

[0045] The harvester head rotator is configured to rotate the harvester head around one or more axis. It is to be understood that the harvester head may comprise one or more rotators configured to rotate around a certain axis respectively. For example, the harvester head rotator may comprise a mechanism that allows the harvester head to rotate around its vertical axis. The harvester head filter is configured to tilt the harvester head. By tilting the harvester head the vertical axis of the harvester head may be tilted. The harvester head may comprise a mechanism that allows the harvester head to be tilted or adjusted in various angles. The ability to rotate and / or tilt the harvester head enhances the machine's capability to handle trees of different

[0046] General - No protection sizes and orientations, as well as to operate effectively on uneven terrain. These functions are especially important in forestry operations where precision and adaptability can significantly impact productivity and the quality of the work performed. The filter and / or rotator can be controlled hydraulically and / or electrically, allowing the operator to adjust the angle of the harvester head as needed during operation. The harvester head clamps are configured to provide a gripping force on a log, i.e. the harvester head clamps are configure to bias a log in the harvester head clamps, for example by engaging a log with two clamp components, arranged on opposite sides of the log, and apply a force in a direction towards the log, such that the log is clamped / gripped / held by the harvester head clamps. The harvester head clamps may comprise mechanical components configured to securely grip and / or hold the tree or log during the harvesting and / or cutting process. These clamps may ensure that the tree or log remains stable and under control while it is being cut, delimbed, and / or processed. The saw bar positioner may be configured control and / or adjust the saw bar's position, e.g. during cutting operations. The saw bar positioner may allow the operator to adjust the angle and position of the saw bar, ensuring precise cuts and reducing the risk of incorrect cuts that could damage the tree or the equipment. By positioning the saw bar correctly, the positioner helps in achieving efficient and smooth cuts, enhancing the overall productivity of the harvester head.

[0047] The present embodiment is advantageous in that the cut-to- length logging harvester vehicle may provide a first flow driving the saw chain with the first pump, while providing a separate second flow to drive at least one of the x, y, z and q, by the second hydraulic pump. This allows the harvester vehicle to control the speed of a saw chain by only controlling generation of the first flow of the first pump, while also controlling other functions of the harvester head, e.g. the positioning / adjustment of the harvester head and / or the bar saw. Hence, the present embodiment provides

[0048] General - No protection a more efficient vehicle for cut-to-length-logging operation, in terms of energy and / or operating time, while also providing higher quality cutting of the logs.

[0049] In an embodiment of the present invention, the hydraulic power unit comprises at least one hydraulic accumulator arranged on the tip side. Furthermore, the harvester head comprises at least one of: a harvester head rotator, a harvester head clamp means, and a harvester head filter. The at least one second hydraulic actuator is configured to mechanically drive at least one of the harvester head rotator, the harvester head clamps, the harvester head filter and the saw bar positioner. The at least one hydraulic accumulator is configured, when in log-cutting mode, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head filter, and the saw bar positioner, by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit, and wherein the at least one hydraulic accumulator is configured to be pressurized by the first hydraulic pump.

[0050] The at least one hydraulic accumulator may be a device used in hydraulic systems to store energy in the form of pressurized hydraulic fluid. It may consist of a cylinder containing hydraulic fluid and a compressible gas (e.g. nitrogen) separated by a piston, bladder, or diaphragm. The stored energy, in form of pressurized hydraulic fluid, may then be used to drive one or more actuators in the harvester vehicle. The hydraulic accumulator may be pressurized, charged up on energy, by a hydraulic pump, such as the first hydraulic pump.

[0051] The present embodiment is advantageous in that one pump, e.g. the first hydraulic pump, may both be used to drive the saw chain during logcutting mode, but also to be pressurize and store energy in the hydraulic accumulator while not in log-cutting mode, e.g. during log-feeding mode. Since the hydraulic accumulator may then be used to drive other actuators during log-cutting mode, this allows the first hydraulic pump to provide the power needed for both driving and controlling the saw chain, and also

[0052] General - No protection indirectly, via the hydraulic accumulator, other actuators configured to move the crane and / or harvester head during log-cutting mode.

[0053] In an embodiment of the present invention, the cut-to-length logging harvester vehicle further comprises a first confluence valve configured, when in the log-feeding mode, to couple the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and harvester head filter.

[0054] The first confluence valve may be configured to join and disconnect two separate flows, i.e. couple and decouple, such that e.g. the first regulated flow may be increased by the second hydraulic flow, or at least a part of the second hydraulic flow. In other words, the confluence valve may be configured to combine / merge / couple the flow from two or more sources into a single flow. It may be used in hydraulic systems to optimize the efficiency and performance of machinery by managing and directing hydraulic fluid flows according to the system's needs.

[0055] The present embodiment is advantageous in that the flow provided to at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and the harvester head filter, may be adjusted according to the operating needs, e.g. increased without adding more pumps to the hydraulic system. Furthermore, the present embodiment allows the parts of the system that generate the flows, e.g. the pump(s), to be downsized. Hence, the cut-to-length logging harvester vehicle may be smaller and / or lighter, which may result in a more efficient overall operation of the harvester vehicle.

[0056] In an embodiment of the present invention, the first hydraulic conduit, when in the log-cutting mode, is separate from the second hydraulic conduit. In other words the first and second hydraulic conduits are separate conduits with separate pressurized hydraulic flows. By the formulation “the

[0057] General - No protection first hydraulic conduit is separate from the second hydraulic conduit” it is here meant that that the first and second conduit are to separate conduits, e.g. hoses, such that they can convey two different flows independent of each other, i.e. a first flow in the first conduit is independent from a second flow in the second conduit. In an example the two separate conduits may be coupled / connected using the first confluence valve.

[0058] The present embodiment is advantageous in that the hydraulic system has increased versatility in terms of what hydraulic flows it can provide to actuators.

[0059] In an embodiment of the present invention, the first hydraulic pump exclusively drives, when in the log-cutting mode, the saw chain. In other words, the first hydraulic pump only powers the first hydraulic actuator, and hence directly and exclusively drives the saw chain. It is advantageous that the first hydraulic pump exclusively drives the saw chain, because the speed of the saw chain may thus be controlled more precisely based on how the first hydraulic pump is operated. For example, by generating a hydraulic flow with a certain pressure and / or flow rate, the speed of the saw chain can be directly predicted / derived more precisely.

[0060] In other words, by exclusively driving the saw chain with the first hydraulic pump during log-cutting mode, the preciseness and reliability of the saw chain control may be improved. If the first hydraulic pump would drive other actuators at the same time, the control of the saw chain may thus be less precise and less reliable.

[0061] In an embodiment of the present invention, the harvester head comprises braking means configured to, when the bar saw is exiting the logcutting mode, reduce the speed of the saw chain. The braking means comprises at least one of: a throttle valve configured to throttle the regulated first hydraulic flow, F1 , and a bypass valve configured to allow the regulated first hydraulic flow, F1 , to bypass the first hydraulic actuator. The braking

[0062] General - No protection means is configured to be controlled based on at least one of: a quantity indicative of the current saw chain speed, a current position of the saw bar positioner, a current position of harvester head clamps, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head. Hence, the cut-to-length logging harvester vehicle may comprise braking means that can be used to stop operation in a hydraulic system to prevent problems by controlling the flow of hydraulic fluid. A bypass valve may be a type of valve used in hydraulic fluid systems to manage hydraulic fluid flow to ensure that actuators and other components receive the correct flow and pressure. It can help prevent overpressure situations, maintain efficient operation, and enable safe and effective maintenance procedures. A throttle valve may be a type of valve used to control the flow rate of a fluid within a hydraulic fluid system. By adjusting the opening of the valve, the amount of fluid passing through can be precisely regulate, thereby controlling the speed and performance of the downstream components.

[0063] The saw chain speed reduction provided by the braking means may be applied at any time to avoid over-speeding of the saw chain. For example, a saw chain speed exceeding a critical speed of 40 m / s should be avoided. Typically, speed reduction should be activated or begin to be activated, prior to approaching the critical speed, a value of which may vary depending on the specific bar saw used in the harvester head. The predetermined log-cutting speed of the saw chain is lower than the critical speed. Hence the predetermined log-cutting speed may be lower than 40 m / s.

[0064] It is to be understood that "a quantity indicative of the current saw chain speed" refers to a measurement or value that represents how fast the saw chain is moving at a given moment. This could be a direct speed measurement (like meters per second) or a related parameter, such as RPM of a motor running the first hydraulic pump, or a parameter related to the operation of the first hydraulic pump, which reflects the saw chain's operational speed.

[0065] General - No protection

[0066] The braking means may be arranged on the tip side of the harvester vehicle, e.g. on the articulated crane and / or on the harvester head. Consequently, the primary regulation of the first hydraulic flow, F1 , may be done on the base side, e.g. on the vehicle frame, and safety / braking regulation of the first hydraulic flow may be done on the tip side, e.g. on the articulated crane and / or the harvester head. In other words, the harvester vehicle is configured to regulate the outputted first hydraulic flow, F1 , on the base side. Further, the harvester vehicle is configured to regulate the already outputted first hydraulic flow by the braking means on the tip side.

[0067] The present embodiment is advantageous in that the breaking means allow the cut-to-length logging harvester vehicle to help manage the hydraulic system by providing controlled stopping / adjustment of the flow, e.g. to prevent / avoid sudden pressure spikes and / or mechanical stress, thereby reducing the risk of equipment damage and improving overall safety for the cut-to-length logging harvester vehicle.

[0068] In an embodiment of the present invention, the first hydraulic pump is configured to control the regulated first hydraulic flow, and wherein is the first hydraulic pump in turn is configured to be controlled by a control unit by controlling a setting of the first hydraulic pump and / or controlling a setting of a power source configured to power the first hydraulic pump. The control unit may be any component or device designed to not only manage and regulate operations within a machinery or system but also to analyze, interpret, and utilize data for decision-making and optimization. The control unit may be a processing circuitry and / or a computer. The control unit may be part of the cut-to-length logging harvester vehicle, i.e. be arranged on the cut- to-length logging harvester vehicle, e.g. in the vehicle frame. It is to be understood that the control unit may control other components and processes, such as any hydraulic pump, braking means and / or actuators of the cut-to-length logging harvester vehicle.

[0069] General - No protection

[0070] The power source may be any device capable of powering the first hydraulic pump. The power source may be an electric motor configured to power the first hydraulic pump.

[0071] Hence, the cut-to-length logging harvester vehicle may comprise a control unit configured to control the first hydraulic pump and / or the power source and thereby regulate the output of the first hydraulic flow, F1 . The control unit may thus be configured to control a speed of the saw chain by controlling the first hydraulic pump and / or the power source to generate a controlled regulated first hydraulic flow, F1 .

[0072] The present embodiment is advantageous in that the control of the first hydraulic flow, especially generating the first hydraulic flow, may be improved, which may result in better cutting result and more energy efficient cutting. The control unit may also allow at least parts of the control to be automized. For example, the control unit may receive input signals and / or data from various sources including sensors and external data feeds, and use this information to make decisions, adjust parameters, and optimize operations. This integration of data processing means, via the control unit, may enhance the cut-to-length logging harvester vehicle ability to monitor performance, to more precisely control an action and to adapt to changing conditions, e.g. operating conditions, thereby improving efficiency, reliability, and overall system performance.

[0073] In an embodiment of the present invention, the control unit is configured to control the first hydraulic pump and / or the power source and the regulated first hydraulic flow based on the proportional dependency. The present embodiment is advantageous in that the control of the speed of the saw chain may be further improved, e.g. in terms of energy efficiency.

[0074] In an embodiment of the present invention, the control unit is configured to control the regulated first hydraulic flow, F1 , using open-loop control. By using “open-loop control” it is here meant operating a hydraulic

[0075] General - No protection system and / or component without feedback to adjust its actions based on the output. In other words commands are sent, e.g. by a control unit or an operator, to the hydraulic components, e.g. the first hydraulic pump, based on predefined instructions or input signals, but it does not monitor or adjust based on the actual performance or status of the hydraulic components.

[0076] The present embodiment is advantageous in that the cut-to- length logging harvester vehicle allows for improved control of the first hydraulic flow, and as a result, of the speed of the saw chain. For example, by using open-loop control, the cut-to-length logging harvester vehicle may perform faster changes in the generation of the first hydraulic flow, and thus faster changes in saw chain speed may be performed. Compared to e.g. closed-loop control this is especially advantageous, because closed-loop control is too slow to handle faster changes. The present embodiment is further advantageous in that open-loop control may be simpler and less expensive than closed-loop systems because they do not require sensors or feedback mechanisms.

[0077] In an embodiment of the present invention, the speed of the saw chain, when in the log-cutting mode, is regulated based on at least one of a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of the harvester head clamp means, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head. For example, the first hydraulic pump, or a motor driving the pump, that drives the first hydraulic actuator and thereby the saw chain, may generate a flow based on predetermined information regarding at least one of a current position of the saw bar positioner, a current position of the harvester head clamp means, and a hydraulic pressure of the regulated first hydraulic flow, in order to better control the speed of the saw chain.

[0078] The present embodiment is advantageous in that control of the speed of the saw chain may be further improved, e.g. in terms of energy efficiency.

[0079] General - No protection

[0080] In an embodiment, a control unit is configured to control the regulated first hydraulic flow, F1 , using closed-loop control. In an example, the harvester vehicle may be configured to regulate the first hydraulic flow using both open-loop control and closed-loop control, such that primarily open-loop control is used for the log-cutting process in log-cutting mode, and closed-loop control is used for the end and / or start of the log-cutting process. Hence, more energy-efficient open-loop control may be used for the majority of the log-cutting process.

[0081] When using open-loop control, the regulation of the first hydraulic flow may be done with “open-loop drive”, i.e. that the recirculation of hydraulic fluid takes place without, or under low, pressure. An alternative embodiment is to use "closed-loop drive", i.e. that the cutting takes place with two (at the moment) dedicated pressure lines connected to the pump, one outgoing and one returning.

[0082] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises at least one flow sensor configured to determine at least one of a first hydraulic flow value and a first hydraulic pressure of at least one of the first hydraulic flow and the second hydraulic flow, wherein at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, is limited via limitation means when at least one of the first hydraulic flow value and the first hydraulic pressure reaches or exceeds a predetermined threshold.

[0083] The at least one flow sensor may be any device that measures the flow rate of the hydraulic fluid within a hydraulic system. It may provide real-time data on the amount of fluid moving through a particular section of the system. The limitation means may comprise relief valves, check valves, throttle valves, shut-off valves, and / or flow control valves. A control unit may be connected to the at least one flow sensor. The control unit may receive flow data indicating the first hydraulic flow rate and / or the first hydraulic pressure, and may be configured to send a command to limit and / or shut off

[0084] General - No protection the first hydraulic flow and / or the first hydraulic pump. The present embodiment is advantageous in that the cut-to-length logging harvester vehicle may detect a flow rate and / or pressure, which can indicate an error and / or faulty operation. Therefore, the present embodiment allows for a calibration to be made, and for an alert threshold to be monitored such that e.g. the system may be shut down when the pressure is too high.

[0085] In a further embodiment, the cut-to-length logging harvester vehicle may comprise a speed sensor configured to measure a speed of a power source. The power source may be, as described earlier, configured to power the first hydraulic pump. The speed sensor may be configured to determine a speed of the power source. The cut-to-length logging harvester vehicle may be configured to limit and / or shut off the operation of the first hydraulic pump and / or the first flow, for example if the speed reaches or exceeds a predetermined threshold.

[0086] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises at least one crane actuator configured to mechanically drive the crane, arranged in the vehicle frame and / or the articulated crane, and a third hydraulic pump configured to power the crane by feeding a third hydraulic flow, F3, to the at least one crane actuator via a third hydraulic conduit. The crane actuator is a mechanical device in a crane that converts hydraulic, pneumatic, or electrical energy into motion, enabling various parts of the crane to move. The at least one crane actuator may be responsible for controlling the crane's movements, such as lifting, lowering, extending, retracting, or rotating the boom or jib.

[0087] The present embodiment is advantageous in that the cut-to- length logging harvester vehicle may provide a hydraulic system that can power crane movement. More specifically, it is advantageous in that the cut- to-length logging harvester vehicle provides a hydraulic system that may control the speed of the saw chain in a more efficient manner, while also controlling the crane.

[0088] General - No protection

[0089] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises a confluence valve configured, when in the log-feeding mode, to, couple at least one of the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, to drive the crane. For example, the cut-to-length logging harvester vehicle may power the crane with the first hydraulic pump and / or the second hydraulic pump. The present embodiment is advantageous in that third flow, F3, may be increased according to the operating needs, by merging at least one of the first, F1 , and second hydraulic flow, F2, with the third hydraulic flow. Furthermore, the present embodiment allows the parts of the system that generate the flows, e.g. the pump(s) and / or accumulators, to be downsized. Hence, the cut-to-length logging harvester vehicle may be smaller and / or lighter, which may result in a more efficient overall operation of the harvester vehicle.

[0090] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises at least one electric motor arranged in the vehicle frame and powered by at least one of: an electric energy storage unit arranged in the vehicle frame, and an electric generator powered by an internal combustion engine, the electric generator and the internal combustion engine arranged in the vehicle frame, wherein at least one of the first hydraulic pump, the hydraulic power unit, and the third hydraulic pump is powered by the at least one electric motor.

[0091] The electric energy storage unit is a device / component / system that stores electrical energy for later use. These units capture produced energy and release it when desired / needed. The electric energy storage unit may comprise a battery and / or a capacitor.

[0092] The present embodiment is advantageous because using electric motors, and / or an electric energy storage unit, to drive pumps in a harvester vehicle offers significant advantages in terms of energy efficiency, precision,

[0093] General - No protection environmental impact, maintenance, and overall operational performance. For example, the control of the first hydraulic pump may be more precise and quicker to adjust. Hence, since the first hydraulic pump drives the saw chain during log-cutting mode, the speed of the saw chain may be controlled in a more precise and versatile manner.

[0094] In an embodiment of the present invention, the cut-to-length logging harvester head further comprises at least one second hydraulic actuator configured to mechanically drive the log-feeding device, and wherein the log-feeding device, when in the log-feeding mode, is powered by at least one of the first hydraulic pump and a hydraulic power unit, wherein the hydraulic power unit is configured, when in log-feeding mode, to power the log-feeding device, by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit.

[0095] In an embodiment of the present invention, the first hydraulic actuator is arranged to receive the regulated first hydraulic flow, F1 , from an external first hydraulic pump. The external first pump may be arranged on a vehicle frame of a cut-to-length logging harvester vehicle. The external first pump may be the first hydraulic pump discussed throughout the application.

[0096] The present embodiment is advantageous in that the first flow may be provided by a single pump, allowing improved control of the saw chain, e.g. in terms of more precise speed control.

[0097] In an embodiment of the present invention, the at least one second hydraulic actuator is arranged to receive the second hydraulic flow, F2, from an external second hydraulic pump. The external second pump may be arranged on a vehicle frame of a cut-to-length logging harvester vehicle. The external second pump may be the second hydraulic pump discussed throughout the application.

[0098] General - No protection

[0099] In an embodiment of the present invention, the hydraulic power unit comprises at least one hydraulic accumulator configured to be pressurized by the regulated first hydraulic flow, F1 , and wherein the at least one hydraulic accumulator is configured to power the at least one second hydraulic actuator.

[0100] In an embodiment of the present invention, the cut-to-length logging harvester head comprises at least one of a harvester head rotator, harvester head clamps, and a harvester head filter, wherein the at least one second hydraulic actuator is configured, if the bar saw is in log-cutting mode, to drive at least one of the harvester head rotator, the harvester head clamps, and the harvester head filter, by the second hydraulic flow, F2.

[0101] In an embodiment of the present invention, the cut-to-length logging harvester head comprises braking means configured to, when the bar saw is exiting log-cutting mode, reduce the speed of the saw chain, wherein the braking means comprises at least one of: a throttle valve configured to throttle the regulated first hydraulic flow, F1 , and a bypass valve configured to allow the regulated first hydraulic flow, F1 , to bypass the first hydraulic actuator, wherein the braking means is configured to be controlled based on at least one of: a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of harvester head clamps, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head

[0102] In an embodiment of the present invention, the log-feeding device comprises feed rollers. The feed rollers may comprise rotating cylindrical components used in forestry equipment, such as logging harvester vehicles, to grip and move logs through the machine. Positioned around the log, they apply pressure and rotate, feeding the log into the cutting or processing mechanisms. The feed rollers allow for more precise control and more

[0103] General - No protection consistent movement of the log during operations like delimbing or processing.

[0104] In an embodiment of the present invention, the cut-to-length logging harvester vehicle operating method comprises performing the following in the log-feeding mode:

[0105] -outputting a first hydraulic flow, F1 , by the first hydraulic pump, and

[0106] -providing the first hydraulic flow, F1 , to the at least one second hydraulic actuator via a second hydraulic conduit to power the log-feeding device, or

[0107] -outputting a second hydraulic flow, F2, by a hydraulic power unit, and

[0108] -providing the second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit to power the logfeeding device.

[0109] Put another way, the cut-to-length logging harvester vehicle operating method provides a hydraulic flow from the first hydraulic pump, or provides a hydraulic flow from a hydraulic power unit, and provides the hydraulic flow to at least one hydraulic actuator that drives the log-feeding device. Hence, the present embodiment provides a method for operating a cut-to-length logging harvester vehicle by operating the harvester in two separate modes, log-cutting mode and log-feeding mode. The present embodiment is advantageous in that a more versatile and precise operating method for a cut-to-length logging harvester vehicle is provided.

[0110] In an embodiment of the present invention, the hydraulic power unit comprises a second hydraulic pump arranged at the base side, and the harvester head comprises at least one of:

[0111] -a harvester head rotator,

[0112] General - No protection

[0113] -harvester head clamps, and -a harvester head tilter.

[0114] Furthermore, the operating method comprises the following in the log cutting mode:

[0115] -outputting the second hydraulic flow, F2, by the second hydraulic pump, and

[0116] -providing the second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit, extending between the base side and the tip side, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head tilt, and the saw bar positioner.

[0117] In an embodiment of the present invention, the hydraulic power unit is arranged in the harvester head and comprises at least one hydraulic accumulator configured to be pressurized by the first hydraulic pump, and the harvester head comprises at least one of:

[0118] -a harvester head rotator,

[0119] -harvester head clamps, and

[0120] -a harvester head tilter.

[0121] Furthermore, the operating method comprises the following in the log-cutting mode: outputting the second hydraulic flow, F2, by the at least one hydraulic accumulator, providing the second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit to power at least one of the harvester head rotator, the harvester head clamps, the harvester head tilter, and the saw bar positioner.

[0122] In an embodiment of the present invention, the operating method comprises reducing the speed of the saw chain when the bar saw is exiting log-cutting mode by at least one of

[0123] General - No protection

[0124] -throttling the first hydraulic flow, and

[0125] -bypassing the first hydraulic actuator such that the regulated first hydraulic flow bypasses the first hydraulic actuator, and wherein reducing the speed of the saw chain is based on at least one of: a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of harvester head clamps, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.

[0126] In an embodiment of the present invention the cut-to-length logging harvester vehicle comprises a first confluence valve, and the operating method comprises:

[0127] -receiving at least one operating condition,

[0128] -coupling, by the first confluence valve, the first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and the harvester head tilt, based on the at least one operating condition. The operating condition may be comprise any status and / or setting of the cut-to- length logging harvest vehicle, and / or any of its parts / components, that affects and / or puts a demand on the operation, e.g. the harvester head rotator, the harvester head clamps, the harvester head tilt, a log-feeding actuator and a delimbing actuator.

[0129] In an embodiment of the present invention, the at least one operating condition comprises at least one of an operating mode of the cut-to- length logging harvester vehicle and an actuator condition of the at least one second hydraulic actuator. The operating mode may be one of many modes that allows a cut-to-length logging harvester vehicle to perform different tasks efficiently. In a log-cutting mode, the saw system is activated to fell trees or buck logs into specific lengths. In a log-feeding mode logs are moved through the machine for delimbing, measuring, and cutting. During a delimbing mode,

[0130] General - No protection branches are removed from felled trees as they pass through the machine. A log handling mode involves the crane or grapple lifting, rotating, and positioning logs for processing or loading. In a travel mode, the vehicle moves to a new location with the drive system engaged while the processing mechanisms are inactive or active. A measuring mode involves sensors and measuring tools to determine log length, diameter, and volume during or after processing. In a standby mode, the vehicle is powered on but remains idle, with systems ready for activation. The actuator condition may be if an actuator is to be used in an open / pressurized condition, i.e. actively driving. The actuator condition may comprise one or more conditions for one or more actuators, e.g. the operating condition may comprise at least one actuator condition, such as one condition for a delimbing driving actuator, and one condition for a log-feeding driving actuator.

[0131] In an embodiment of the present invention the cut-to-length logging harvester vehicle comprises a third hydraulic pump arranged in the vehicle frame and at least one crane actuator configured to drive the crane, and the operating method comprises:

[0132] -outputting a third hydraulic flow, F3, by the third hydraulic pump, and

[0133] -providing the third hydraulic flow, F3, to the crane actuator via a third hydraulic conduit to power the crane.

[0134] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises a second confluence valve, and the operating method comprising:

[0135] -receiving at least one operating condition,

[0136] -coupling, by the second confluence valve, at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, to drive the crane, based on the at least one operating condition.

[0137] General - No protection

[0138] The second confluence valve may be configured to join and disconnect two separate flows, i.e. couple and decouple, such that e.g. the third regulated flow may be increased by the first and / or second hydraulic flow, or at least a part of the first / second hydraulic flow. In other words, the second confluence valve may be configured to combine / merge / couple the flow from two or more sources into a single flow. It may be used in hydraulic systems to optimize the efficiency and performance of machinery by managing and directing hydraulic fluid flows according to the system's needs.

[0139] The present embodiment is advantageous in that the flows may be redirected to adjust a flow according to the operating needs, e.g. increasing a flow without adding more pumps to the hydraulic system. Furthermore, the present embodiment allows the parts of the system that generate the flows, e.g. the pump(s), to be downsized. Hence, the cut-to- length logging harvester vehicle may be smaller and / or lighter, which may result in a more efficient overall operation of the harvester vehicle.

[0140] In an embodiment of the present invention, the cut-to-length logging harvester vehicle comprises a control unit, and the operating method further comprises controlling, with the control unit, at least one of:

[0141] -outputting the first hydraulic flow, F1 , by controlling the first hydraulic pump or controlling a power source configured to power the first hydraulic pump,

[0142] -outputting the second hydraulic flow, F2, by controlling the hydraulic power unit,

[0143] -outputting the third hydraulic flow, F3, by controlling the third hydraulic pump,

[0144] -coupling by the first confluence valve, and

[0145] -coupling by the second confluence valve.

[0146] In other words, the control unit may be configured to control any of the components in the harvester vehicle.

[0147] General - No protection

[0148] Brief description of the drawings

[0149] The invention will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments, with reference to the appended drawings, in which:

[0150] Figure 1 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0151] Figure 2 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0152] Figure 3 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0153] Figure 4 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0154] Figure 5 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0155] Figure 6 schematically illustrates a system of the cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0156] Figure 7 schematically illustrates a side-view of a cut-to-length logging harvester vehicle according to an exemplifying embodiment of the invention.

[0157] Figure 8 schematically illustrates a side-view of a cut-to-length logging harvester head according to an exemplifying embodiment of the invention.

[0158] General - No protection

[0159] Figure 9 schematically illustrates a front-view of a cut-to-length logging harvester head according to an exemplifying embodiment of the invention.

[0160] Figure 10 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method according to exemplifying embodiments of the present invention.

[0161] Figure 11 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method according to exemplifying embodiments of the present invention.

[0162] Figure 12 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method according to exemplifying embodiments of the present invention.

[0163] All figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.

[0164] Detailed description of embodiments

[0165] It is to be understood that Figs. 1-6 schematically illustrates an overview of a hydraulic system of a harvester vehicle 100 with pumps, motors, actuators, valves and conduits, and also related components e.g. control units and sensors.

[0166] Fig. 1 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The harvester vehicle 100 comprises a vehicle frame 110 comprising a propulsion arrangement. The propulsion arrangement is not shown, and may typically be any arrangement configured to drive the harvester vehicle 100 using e.g. an electric motor or a combustion engine. The harvester vehicle 100 comprises an articulated crane 120 connected at its base side to the vehicle frame 110 and connected at its tip side to a harvester head 130. The harvester head 130 comprises a bar saw 140 and a log-feeding device 160, wherein the bar saw 140 is configured to operate in a

[0167] General - No protection log-cutting mode and the log-feeding device 160 is configured to operate in a log-feeding mode. The bar saw 140 comprises a saw bar, a saw chain and a saw bar positioner (all of which are not shown in Fig. 1 , but shown in Fig. 8 and Fig. 9).

[0168] The harvester vehicle 100 comprises a first hydraulic actuator 150 and a first hydraulic pump 180, wherein the first hydraulic pump 180 is configured to output a regulated first hydraulic flow, F1 , to the first hydraulic actuator 150, i.e. the first hydraulic pump 180 powers the first hydraulic actuator 150. The first hydraulic pump 180 is arranged on the base side of the articulated crane 120, here on the vehicle frame 110. It is to be understood that the first hydraulic pump 180 may be arranged on a part of the harvester vehicle 100 that is not part of the vehicle frame 110 but still on the base side of the articulated crane 120. For example, the hydraulic pump 180 may be arranged in the connecting region of the articulated crane 120 to the vehicle frame 110. The first hydraulic pump 180 is configured to, when in the logcutting mode, to control a speed of the saw chain towards a predetermined log-cutting speed, by the regulated first hydraulic flow, F1 . The first hydraulic actuator 150 is configured to drive the saw chain.

[0169] The first hydraulic pump 180 controls the speed of the saw chain by providing / outputting a hydraulic flow in a regulated manner to the first hydraulic actuator 150 via a first hydraulic conduit 190 extending between the hydraulic pump 180 on the base side and the first hydraulic actuator 150 on the tip side, i.e. by regulating / controlling the flow generation of the hydraulic pump 180 the speed of the saw chain is thereby regulated / controlled. The first hydraulic conduit 190 fluidly connects the first hydraulic pump 180 and the first hydraulic actuator 150 with e.g. a tube / hose going from the first hydraulic pump180, via the articulated crane 120, to the harvester head 130 and to the at least one second hydraulic actuator 170. It is to be understood that the first hydraulic actuator 150 is here arranged on the harvester head 130. The harvester vehicle 100 is configured to, during log-cutting mode, to

[0170] General - No protection control / regulate the speed of the saw chain with a proportional dependency on the regulated first hydraulic flow, F1.

[0171] Accordingly, the harvester vehicle 100 is operable in a log-cutting mode wherein the bar saw 140 is being used, and operable in a log-feeding mode wherein the log-feeding device 160 is being used. The log-cutting mode is generally distinct from the log-feeding mode, since it is beneficial to keep a log in position during cutting to perform a controlled and even cut at a desired length. Furthermore, when in the log-cutting mode, the harvester vehicle is configured to convey the regulated first hydraulic flow, F1 , in an unthrottled manner, from the first hydraulic pump 180 to the first hydraulic actuator 150. Hence, the speed of the saw chain is controlled by only controlling the first hydraulic pump 180 to generate a first flow that is regulated according to a desired predetermined saw chain speed. The first hydraulic pump 180 exclusively drives, when in the log-cutting mode, the saw chain, i.e. the harvester vehicle 100 is configured to exclusively drive the saw chain using the first flow, F1 , from the first hydraulic pump 180 during log-cutting, such that the speed of the saw chain is controlled directly by controlling the generation of the first flow, F1 , since the first hydraulic flow is not provided to any other actuators..

[0172] Furthermore, in Fig. 1 , the harvester vehicle 100 comprises a second hydraulic actuator 170 configured to drive the log-feeding device 160. The harvester vehicle 100 further comprises a hydraulic power unit 200 configured to power the log-feeding device 160. When in log-feeding mode, the hydraulic power unit 200 and / or the first hydraulic pump 180 powers the log-feeding device 160. The log-feeding device 160 is powered by outputting / providing a second hydraulic flow, F2, to the second hydraulic actuator 170 via a second hydraulic conduit 210. The second hydraulic conduit 210 extends at least between the hydraulic power unit 200 and the second hydraulic actuator 170. The second hydraulic conduit 210 fluidly connects the hydraulic power unit 200 and the second hydraulic actuator 170. The first hydraulic conduit 190 is separate from the second hydraulic conduit

[0173] General - No protection

[0174] 210, i.e. the two conduits may have two separate flows of different flow rates and pressure.

[0175] Figure 2 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The system comprises a hydraulic system of the harvester vehicle. It should be noted that the harvester vehicle 100 described in Fig. 2 has several features in common with the harvester vehicle 100 described in Fig. 1 , and it is hereby referred to Fig. 1 and the associated text for an increased understanding of some of the features and / or functions of the harvester vehicle 100. In Fig. 2 the harvester vehicle 100 comprises a plurality of second hydraulic actuators 170, i.e. the at least one second actuator 170 comprises a plurality of second hydraulic actuators 170. Here, the harvester head 130 comprises a log-feeding device 160, a harvester head rotator 132, harvester head clamps 134, and a harvester head filter 136. Each of these comprises at least one second hydraulic actuator 170 configured to power the respective component. It is to be understood that the harvester head 130 may comprise one or more of these components, and also other components used by the harvester vehicle 100.

[0176] In Fig. 2 the hydraulic power unit 200 comprises a second hydraulic pump 200a arranged at the base side. The second hydraulic pump 200a is configured, when in log-cutting mode, to power at least one of the logfeeding device 160, the harvester head rotator 132, the harvester head clamps 134, the harvester head filter 136 and the saw bar positioner 146 by feeding a second hydraulic flow, F2, to at least one of the plurality of second hydraulic actuator 170 via the second hydraulic conduit 210 extending between the base side and the tip side. The second hydraulic conduit 210 is configured to fluidly connect the second hydraulic pump 200a and the plurality of second actuators 170. The plurality of second hydraulic actuators 170 is configured to, respectively, mechanically drive the harvester head rotator, the harvester head clamp means, the harvester head filter, and the saw bar

[0177] General - No protection positioner. For example one second hydraulic actuator 170 for each of the components 160, 132, 134, 136, 146.

[0178] The harvester vehicle 100 comprises a control unit 270, wherein the control unit 270 is configured to control the first hydraulic pump 180 and / or a power source (not shown) configured to power the first hydraulic pump 180. The power source may be a motor / engine, e.g. an electric motor. The first hydraulic pump 180 is configured to control the regulated first hydraulic flow, F1 , and wherein the first hydraulic pump 180 in turn is configured to be controlled by the control unit 270. The control unit 270 is configured to control a setting of the first hydraulic pump 180 and / or control a setting of the power source configured to power the first hydraulic pump 180. Hence, the control unit 270 is configured to control the first hydraulic pump 180 and / or the power source and the regulated first hydraulic flow based on the proportional dependency.

[0179] The plurality of second hydraulic actuators 170 may be powered individually by the second hydraulic pump 200a, and it may be controlled e.g. by the control unit 270. The control unit 270 may be configured to e.g. control valves to allow the second hydraulic flow, F2, to reach the log-feeding device 160, the harvester head rotator 132, the harvester head clamps 134, the harvester head filter 136 and / or the saw bar positioner 146. The plurality of second hydraulic actuators 170 may be powered together without using valves to direct flow to certain second hydraulic actuators 170.

[0180] The control unit 270 is configured to control the first hydraulic pump 180, and / or power source powering the first hydraulic pump 180, such that the regulated first hydraulic flow is based on a proportional dependency between the first hydraulic pump 180 and the operation of the bar saw. The proportional dependency is based on the regulated first hydraulic flow. Here, the control unit 270 is configured to control the regulated first hydraulic flow, F1 , using open-loop control. By using open-loop control of the first hydraulic flow, F1 , the harvester vehicle 100, such as one shown in Figs. 1-6, can, adjust the speed of the saw chain without feedback. In other words

[0181] General - No protection commands are sent, e.g. by a control unit or an operator, to the hydraulic components, e.g. the first hydraulic pump 180 and / or its power source, based on predefined instructions or input signals, but it does not monitor or adjust based on the actual performance or status of the saw chain.

[0182] As an alternative, closed-loop control may be envisioned for at least parts of the operation of the saw chain. As an example, the control unit 270 may regulate the first hydraulic flow, F1 , based on a measurable metric related to cutting of the log by the bar saw 140, e.g. a resistance exerted by a log being cut by the saw chain. The resistance may be a current resistance, e.g. the electrical resistance within the saw's motor / actuator or electrical circuit that affects the flow of electric current. This resistance determines how much the current is opposed as it travels through the saw's components. In an example situation, a quick drop in resistance when cutting of a log is about to be completed needs to be addressed to avoid over-speeding of the saw chain, and an associated risk of saw chain breakage. In an example, a sensor detects a resistance, e.g. a current resistance during operation of the bar saw, which may indicate an operating condition of the bar saw during cutting of the tree which should be compensated for. The compensation may be performed by the control unit 270 by controlling the first hydraulic pump 180 and / or the power source configured to power the first hydraulic pump 180. Closed-loop operation may be used advantageously at an end phase (and possibly a start phase) of sawing through a log.

[0183] Figure 3 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The system comprises a hydraulic system of the harvester vehicle. It should be noted that the harvester vehicle 100 described in Fig. 3 has several features in common with the harvester vehicle 100 described in Figs. 1 and 2, and it is hereby referred to Fig. 1 and 2 and the associated

[0184] General - No protection texts for an increased understanding of some of the features and / or functions of the harvester vehicle 100.

[0185] In Fig. 3, the harvester vehicle 100 comprises at least one hydraulic accumulator 200b arranged on the tip side. Furthermore, the harvester head 130 comprises a log-feeding device 160, a harvester head rotator 132, a harvester head clamp means 134, a harvester head filter 136 and a saw bar positioner 146. Furthermore, the harvester head 130 comprises a plurality of second hydraulic actuators 170 configured to respectively drive the log-feeding device 160, the harvester head rotator 132, the harvester head clamps 134, the harvester head filter 136 and the saw bar positioner 146. The at least one hydraulic accumulator 200b is configured, when in log-cutting mode, to power at least one of the harvester head rotator 132, the harvester head clamps 134, the harvester head filter 136, and the saw bar positioner 146, by feeding a second hydraulic flow, F2, to the plurality of second hydraulic actuators 170 via the second hydraulic conduit. The at least one hydraulic accumulator 200b is configured to be pressurized before driving any of the second hydraulic actuators, which here is performed by the first hydraulic pump 180.

[0186] Figure 4 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The system comprises a hydraulic system of the harvester vehicle. It should be noted that the harvester vehicle 100 described in Fig. 4 has several features in common with the harvester vehicle 100 described in Figs. 1-3, and it is hereby referred to Figs. 1-3 and the associated texts for an increased understanding of some of the features and / or functions of the harvester vehicle 100.

[0187] In Fig. 4 the harvester vehicle 100 comprises a first confluence valve 250 configured, when in the log-feeding mode, to couple the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device 160, the harvester head rotator 132, the harvester

[0188] General - No protection head clamp means 134, and the harvester head tilter 136. The confluence valve 250 allows the flow generated by the first hydraulic pump 180 and the second hydraulic pump 200a to be combined, such that a flow greater than either one of the first flow, F1 , and the second flow, F2, can be created, and be used to power for example the log-feeding device 160. The log-feeding device 160 may need extra power to feed logs in certain arrangements of the harvester head 130 such that the log-feeding device 160 needs to counteract the gravitational force to a larger extent, and it may also need extra power when feeding larger / heavier logs. Further, the typical flow required to drive the operation of the log-feeding device 160 is greater than the flow required to drive the operation of the saw chain of the bar saw 140.

[0189] The harvester vehicle 100 further comprises braking means 260 configured to reduce the speed of the saw chain when the bar saw is exiting the log-cutting mode. The braking means 260 comprises a throttle valve and / or a bypass valve, arranged in the harvester head 130, in connection with the first hydraulic actuator 150. The throttle valve is configured to throttle the regulated first hydraulic flow, F1 , and the bypass valve is configured to allow the regulated first hydraulic flow, F1 , to bypass the first hydraulic actuator 150. The breaking means 260 thus stop the flow going to the first hydraulic actuator 150, and thereby stopping the drive of the saw chain of the bar saw 140. The braking means 260 is configured to be controlled based on at least one of: a quantity indicative of the current saw chain speed, a current position of the saw bar positioner 146, a current position of harvester head clamps 134, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head 130. The quantity indicative of the current saw chain speed may be a measured speed of the saw chain, e.g. measured by a speed sensor. A control unit 270 may be configured to control the breaking means 260 accordingly.

[0190] The harvester vehicle 100 further comprises a first flow sensor 280a arranged in the harvester head 130 and in connection with the first hydraulic conduit 190. The first flow sensor 280a is configured to determine at

[0191] General - No protection least one of a first hydraulic flow value and a first hydraulic pressure of the first hydraulic flow. A hydraulic flow value may be a flow rate, e.g. measured in volume of hydraulic fluid passing a cross section of a conduit during a unit of time.

[0192] The harvester vehicle 100 further comprises a second flow sensor 280b arranged in the harvester head 130 and in connection with the second hydraulic conduit 210. The second flow sensor 280b is configured to determine at least one of a second hydraulic flow value and a second hydraulic pressure of the second hydraulic flow. It is to be understood that the second flow sensor 280b may be configured to determine at least one of a third hydraulic flow value and a third hydraulic pressure of the second hydraulic flow. The third hydraulic flow value and the third hydraulic pressure may indicate a flow value and a hydraulic pressure indicative of a coupled flow consisting of at least a part of the first flow, F1 , and the second flow, F2, by the confluence valve 250. The harvester vehicle 100 is configured to limit, e.g. by the control unit 270, at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, when at least one of the first hydraulic flow value and the first hydraulic pressure reaches or exceeds a predetermined threshold. For example, in order to shut down the flow if an overpressure is detected, to avoid damage to the harvester vehicle 100. The control unit 270 may receive flow data from the flow sensors 280. It is to be understood that the flow sensors 280 may be arranged on other parts of the first hydraulic conduit 190 and the second hydraulic conduit 210.

[0193] Figure 5 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The system comprises a hydraulic system of the harvester vehicle. It should be noted that the harvester vehicle 100 described in Fig. 5 has several features in common with the harvester vehicle 100 described in Figs. 1-4, and it is hereby referred to Figs. 1-4 and the associated texts for an

[0194] General - No protection increased understanding of some of the features and / or functions of the harvester vehicle 100.

[0195] In Fig. 5, the harvester vehicle 100 comprises a third hydraulic pump 300 and a crane actuator 290. The crane actuator 290 is arranged in the vehicle frame and is configured to mechanically drive the articulated crane 120 and control a movement and / or an action of the articulated crane 120. The third hydraulic pump 300 is configured to power the crane by generating and feeding a third hydraulic flow, F3, to the at least one crane actuator via a third hydraulic conduit 310. The third hydraulic pump 300 is arranged on the vehicle frame 110.

[0196] The harvester vehicle 100 comprises a second confluence valve 320 configured to couple at least one of the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, when the harvester vehicle 100 is operating in the log-feeding mode, to drive the crane. For example, the crane actuator 290 may require more power which the first hydraulic pump 180 and / or the second hydraulic pump 200a may provide. In an example, the combination of the first flow, F1 , and the third flow, F3, is sufficient to power the crane actuator 290 and drive the crane 120. This my be the case for example if the crane 120 needs to be operated in log-feeding mode, while no cutting is performed. Likewise, the second flow, F2, may be combined with the third hydraulic flow, F3, during log-cutting mode.

[0197] Figure 6 schematically illustrates a system of the cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The system comprises a hydraulic system of the harvester vehicle. It should be noted that the harvester vehicle 100 described in Fig. 6 has several features in common with the harvester vehicle 100 described in Figs. 1-5, and it is hereby referred to Figs. 1-5 and the associated texts for an increased understanding of some of the features and / or functions of the harvester vehicle 100.

[0198] General - No protection

[0199] In Fig. 6, the harvester vehicle comprises a third hydraulic pump 300 that exclusively provides a third flow, F3, to a crane actuator 290.

[0200] In Fig. 6, the harvester vehicle comprises a motor 330 arranged in the vehicle frame 110. The motor 330 is powered by at least one of an electric energy storage unit 340 arranged in the vehicle frame 110, and an electric generator 350. Hence, the motor 330 is an electric motor. The electric generator 350 and the internal combustion engine 360 are arranged in the vehicle frame 110. The electric generator 350 is powered by an internal combustion engine 360. At least one of the first hydraulic pump 180, the hydraulic power unit 200, and the third hydraulic pump 300 is powered by the at least one electric motor 330.

[0201] Figure 7 schematically illustrates a side-view of a cut-to-length logging harvester vehicle 100 according to an exemplifying embodiment of the invention. The harvester vehicle 100 comprises a vehicle frame 110, here a chassis, and an articulated crane 120 rotatably mounted on the vehicle frame 110 at its base side. The harvester vehicle further comprises a first hydraulic pump 180 and a second hydraulic pump 200a, arranged on the vehicle frame 110. The harvester vehicle 100 comprises a harvester head 130 mounted on the tip side of the articulated crane 120. The harvester vehicle 100 comprises a first conduit 190 and a second conduit 210 which extend from first and second hydraulic pump 180, 200a respectively. Here the first conduit 190 and the second conduit 210 comprises a respective hose that conveys the hydraulic flows to a respective hydraulic interface 410, 420. The first conduit 190 connects to the harvester head 130 at a first hydraulic interface 410, and the second conduit 210 connects to the harvester head 130 at a second hydraulic interface 420. The harvester head 130 comprises a bar saw (not shown) and a log-feeding device (not shown), and the harvester head functions are powered by the first and second hydraulic flow generated by the first hydraulic pump 180 and the second hydraulic pump 200a.

[0202] General - No protection

[0203] Figure 8 schematically illustrates a side-view of a cut-to-length logging harvester head 130 according to an exemplifying embodiment of the invention. It should be noted that the harvester head 130 described in Fig. 8 has several features in common with the harvester head 130 described in Figs. 1-7, and it is hereby referred to Figs. 1-7 and the associated texts for an increased understanding of some of the features and / or functions of the harvester head 130. The harvester head 130 comprises a bar saw 140 operable in a log-cutting mode, a log-feeding device 160 operable in a logfeeding mode. The log-feeding device comprises feed rollers 530, configured to move a log through the harvester head 130 into position for cutting / sawing, such that the cut is performed at a desired location along the log. Furthermore, the harvester head 130 comprises a harvester head rotator 132 arranged on a top part of the harvester head, in the interface between the articulated crane 120 and the harvester head 130, configured to rotate the harvester head around a second axis. The harvester head 130 comprises harvester head clamp means 134, here comprising a set of harvester head clamps 134 configured to clamp onto a log and hold it in place. The harvester head 130 comprises a harvester head tilt 136 configured to tilt the harvester head 130, i.e. rotate at least a part of the harvester head 130 around a third axis.

[0204] The harvester head 130 comprises a first actuator 150 configured to drive the bar saw 140. The harvester head 130 comprises a plurality of second hydraulic accumulators 170 that mechanically drive the functions of the harvester head rotator 132, the harvester head clamp means 134, the harvester head tilt 136, the log-feeding device 160 and the saw bar positioner (not shown) of the bar saw 140. The harvester head 130 comprises a first hydraulic interface 410 configured to receive a first hydraulic flow, F1 , from an external first hydraulic pump (not shown). The external first hydraulic pump may be the first hydraulic pump 180 as described in Figs. 1-6.

[0205] Here, the harvester head 130 comprises a hydraulic accumulator 200b that is configured to power the plurality of second hydraulic actuators

[0206] General - No protection

[0207] 170 by providing a second hydraulic flow, F2, to the second hydraulic actuators 170. The hydraulic accumulator 200b may be powered, i.e. pressurized, by the first hydraulic flow, F1 , entering the harvester head 130 via the hydraulic interface 410. The at least one second hydraulic actuator 170 is configured, if the bar saw 140 is in log-cutting mode, to drive at least one of the harvester head rotator 132, the harvester head clamps 134, the saw bar positioner (now shown), the log-feeding device 160, and the harvester head filter 136, by the second hydraulic flow, F2. In an example, the second hydraulic actuators 170 may receive a second hydraulic flow, F2, from an external second hydraulic pump, e.g. via a hose / conduit connected to the hydraulic interface 410. The external second hydraulic pump may be the second hydraulic pump 200a as described in Figs. 1-6

[0208] Figure 9 schematically illustrates a front-view of a cut-to-length logging harvester head 130 according to an exemplifying embodiment of the invention. It should be noted that the harvester head 130 described in Fig. 9 has several features in common with the harvester head 130 described in Figs. 1-8, and it is hereby referred to Fig. 1-8 and the associated texts for an increased understanding of some of the features and / or functions of the harvester head 130.

[0209] In Fig. 9, a bar saw 140 of the harvester head 130 can be more clearly viewed. The bar saw 140 comprises a saw bar 132, upon which a saw chain 144 is arranged, such that the saw chain 134 rotates around the saw bar 132 during log-cutting mode, at a saw chain speed. The bar saw 140 is positioned by a saw bar positioner 146 arranged in connection with the saw bar 142 in thar harvester head 130. The saw bar positioner 146 is configured to control a position of the bar saw 142 and thereby the perform a cutting motion through the log being cut, while the saw chain 144 is rotating, such that the bar saw 142 may saw and pass through the log.

[0210] The saw bar positioner 146 is configured to rotate the saw bar 142 around an axis which is parallel with the longitudinal axis of the harvester

[0211] General - No protection head 130 and the longitudinal axis of the log to be cut, specifically around a pivot point located at an end of the saw bar 142, such that a cross-sectional cut of a log may be performed by the bar saw 140. The cutting motion of the bar saw 142 is performed in a cutting direction, Vi , of the bar saw 142 illustrated by the dashed arrow in Fig. 9.

[0212] Figure 10 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method 600 according to exemplifying embodiments of the present invention. The cut-to-length logging harvester vehicle operating method 600 is used for operating a harvester vehicle 100 as described throughout the application and Figs. 1-9.

[0213] The operating method 600 comprises operating a cut-to-length logging harvester vehicle in the log-cutting mode or the log-feeding mode. The operating method 600 may comprise determining an operating mode 800, either automatically or manually. For example, the process of cutting a log in a cut-to-length logging harvester vehicle may be performed in a fully automatic manner, or partially automatic, or fully manual, wherein any manual input may be input by an operator of the harvester vehicle. In the log-cutting mode the following is performed according to the operating method 600: controlling 630 a speed of the saw chain by the first hydraulic pump via the regulated first hydraulic flow, F1 , based on a proportional dependency on the regulated first flow, towards a predetermined log-cutting speed. This is at least partially achieved by outputting 610 a regulated first hydraulic flow, F1 , by the first hydraulic pump, and providing 620, the regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit to drive the saw chain. The operating method 600 controls the speed of the saw chain 630, during log-cutting mode, by providing an unthrottled first hydraulic flow exclusively to the first hydraulic actuator configured to mechanically drive the saw chain. Hence, the speed of the saw chain may be controlled directly by controlling the flow generation of the first hydraulic pump and / or by controlling a motor that powers the first hydraulic pump.

[0214] General - No protection

[0215] The operating method 600 comprises performing the following in log-feeding mode: outputting 640 a first hydraulic flow, F1 , by the first hydraulic pump, and providing 650 the first hydraulic flow, F1 , to the at least one second hydraulic actuator via a second hydraulic conduit to power the log-feeding device.

[0216] Figure 11 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method 600 according to exemplifying embodiments of the present invention. It should be noted that the operating method 600 described in Fig. 10 has several features in common with the operating method 600 described in Fig. 9, and it is hereby referred to Fig. 9 and the associated text for an increased understanding of some of the features and / or functions of the operating method 600.

[0217] The operating method 600 also comprises, in log-feeding mode, the following option: outputting 660 a second hydraulic flow, F2, by a hydraulic power unit, and providing 670 the second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit to power the log-feeding device. Hence, the method may comprise outputting a hydraulic flow from

[0218] The operating method 600 comprises at least one of outputting 665 the second hydraulic flow, F2, by the second hydraulic pump, and outputting 667 the second hydraulic flow, F2, by the at least one hydraulic accumulator. Further, the operating method 600 comprises providing 680 the second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head tilt, and the saw bar positioner.

[0219] Furthermore, the operating method 600 comprises reducing 690 the speed of the saw chain when the bar saw is exiting log-cutting mode. Reducing 690 the speed of the saw chain can be done by throttling 692 the first hydraulic flow, and / or bypassing 694 the first hydraulic actuator such that

[0220] General - No protection the regulated first hydraulic flow bypasses the first hydraulic actuator. Reducing 690 the speed of the saw chain is based on at least one of: a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of harvester head clamps, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.

[0221] The cut-to-length logging harvester vehicle comprises a first confluence valve, and the operating method may comprise receiving 700 at least one operating condition, and coupling 710, by the first confluence valve, the first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and the harvester head tilt, based on the at least one operating condition. The at least one operating condition comprises at least one of an operating mode of the cut-to-length logging harvester vehicle and an actuator condition of the at least one second hydraulic actuator.

[0222] Figure 12 schematically illustrates various steps of a cut-to-length logging harvester vehicle operating method 600 according to exemplifying embodiments of the present invention.

[0223] In the embodiment described in Fig. 12, the cut-to-length logging harvester vehicle comprises a third hydraulic pump arranged in the vehicle frame and at least one crane actuator configured to drive the crane. The operating method further comprises outputting 720 a third hydraulic flow, F3, by the third hydraulic pump, and providing 730 the third hydraulic flow, F3, to the crane actuator via a third hydraulic conduit to power the crane. The harvester vehicle may also comprise a second confluence valve, and then the operating method further comprises receiving 740 at least one operating condition, and coupling 750, by the second confluence valve, at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, to drive the crane, based on the at least one operating condition.

[0224] General - No protection

[0225] Further, the harvester vehicle may comprise a control unit, wherein the operating method further comprises, controlling 900, with the control unit, the first hydraulic pump, the hydraulic power unit (i.e. the second hydraulic pump and / or the hydraulic accumulator), and the third hydraulic pump. Hence, controlling 900 may comprise control of the outputting of the first hydraulic flow, F1 , and / or control of the outputting the second hydraulic flow, F2, and / or control of the outputting the third hydraulic flow, F3. Furthermore, the controlling 900 may comprise controlling the coupling by the first confluence valve, and / or the coupling by the second confluence valve.

[0226] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. The skilled person understands that many modifications, variations, and alterations are conceivable within the scope as defined in the appended claims.

[0227] Additionally, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.

[0228] General - No protection

Claims

47Claims1 . A cut-to-length logging harvester vehicle (100), comprising: a vehicle frame (110) having a propulsion arrangement; a harvester head (130) having a bar saw (140) operable in a log-cutting mode, said bar saw (140) having a saw bar (142), a saw chain (144), and a saw bar positioner (146) configured to control a position of the bar saw, a log-feeding device (160) operable in a log-feeding mode; and a first hydraulic actuator (150) configured to mechanically drive the saw chain (142); an articulated crane (120) connected at its base side to the vehicle frame and connected at its tip side to the harvester head (130); a first hydraulic pump (180) arranged at the base side and configured, when in the log-cutting mode, to control a speed of the saw chain (142) towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, F1 , to the first hydraulic actuator (150) via a first hydraulic conduit (190) extending between the base side and the tip side; wherein the speed of the saw chain has, when in the log-cutting mode, a proportional dependency on the regulated first hydraulic flow, F1 .

2. The cut-to-length logging harvester vehicle according to claim 1 , when in the log-cutting mode, is configured to convey the regulated first hydraulic flow, F1 , unthrottled from the first hydraulic pump (180) to the first hydraulic actuator (150).

3. The cut-to-length logging harvester vehicle according to claim 1 or 2, wherein the harvester head comprises at least one second hydraulic actuator (170) configured to mechanically drive the log-feeding device, and wherein the log-feeding device, when in the log-feeding mode, is powered by at least one of the first hydraulic pump and a hydraulic power unit (200), wherein the hydraulic power unit is configured, when in log-feeding mode,General - No protection48 to power the log-feeding device, by outputting a second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit (210).

4. The cut-to-length logging harvester vehicle according to claim 3, wherein the hydraulic power unit comprises a second hydraulic pump (200a) arranged at the base side, and wherein the harvester head comprises at least one of: a harvester head rotator (132), harvester head clamps (134), and a harvester head filter (136), wherein the at least one second hydraulic actuator is configured to mechanically drive at least one of the harvester head rotator, the harvester head clamp means, the harvester head filter, and the saw bar positioner, and wherein the second hydraulic pump is configured, when in log-cutting mode, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head filter and the saw bar positioner by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit extending between the base side and the tip side.

5. The cut-to-length logging harvester vehicle according to claim 3, wherein the hydraulic power unit comprises at least one hydraulic accumulator (200b) arranged on the tip side, wherein the harvester head comprises: at least one of: a harvester head rotator (132), and a harvester head clamp means (134), harvester head tilt (136), wherein the at least one second hydraulic actuator is configured to mechanically drive at least one of the harvester head rotator, the harvester head clamps, the harvester head filter and the saw bar positioner,General - No protection49 wherein the at least one hydraulic accumulator is configured, when in logcutting mode, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head filter, and the saw bar positioner, by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit, and wherein the at least one hydraulic accumulator is configured to be pressurized by the first hydraulic pump.

6. The cut-to-length logging harvester vehicle according to any one of claims 3 to 5, further comprising a first confluence valve (250) configured, when in the log-feeding mode, to couple the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and the harvester head filter.

7. The cut-to-length logging harvester vehicle according to any one of claims 3 to 6, wherein the first hydraulic conduit, when in the log-cutting mode, is separate from the second hydraulic conduit.

8. The cut-to-length logging harvester vehicle according to any one of the preceding claims, wherein the first hydraulic pump exclusively drives, when in the log-cutting mode, the saw chain.

9. The cut-to-length logging harvester vehicle according to any one of the preceding claims, wherein the harvester head comprises braking means (260) configured to, when the bar saw is exiting the log-cutting mode, reduce the speed of the saw chain, wherein the braking means comprises at least one of: a throttle valve configured to throttle the regulated first hydraulic flow, F1 , and a bypass valve configured to allow the regulated first hydraulic flow, F1 , to bypass the first hydraulic actuator,General - No protection50 wherein the braking means is configured to be controlled based on at least one of: a quantity indicative of the current saw chain speed, a current position of the saw bar positioner, a current position of harvester head clamps, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.

10. The cut-to-length logging harvester vehicle according to any one of the preceding claims, wherein the first hydraulic pump is configured to control the regulated first hydraulic flow, and wherein is the first hydraulic pump in turn is configured to be controlled by a control unit (270) by controlling a setting of the first hydraulic pump and / or controlling a setting of a power source configured to power the first hydraulic pump.11 . The cut-to length logging harvester vehicle according to claim 10, wherein the control unit is configured to control the first hydraulic pump and / or the power source and the regulated first hydraulic flow based on the proportional dependency.

12. The cut-to-length logging harvester vehicle according to claim 10 or 11 , wherein the control unit is configured to control the regulated first hydraulic flow, F1 , using open-loop control.

13. The cut-to length logging harvester vehicle according to any one of the preceding claims, wherein the speed of the saw chain, when in the log-cutting mode, is regulated based on at least one of a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of the harvester head clamp means, and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.General - No protection14. The cut-to-length logging harvester vehicle according to any one of the preceding claims, comprising at least one flow sensor (280) configured to determine at least one of a first hydraulic flow value and a first hydraulic pressure of at least one of the first hydraulic flow and the second hydraulic flow, wherein at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, is limited via limitation means when at least one of the first hydraulic flow value and the first hydraulic pressure reaches or exceeds a predetermined threshold.

15. The cut-to-length logging harvester vehicle according to any one of the preceding claims, wherein the cut-to-length logging harvester vehicle comprises: at least one crane actuator (290) configured to mechanically drive the crane, arranged in the vehicle frame and / or the articulated crane, and a third hydraulic pump (300) configured to power the crane by feeding a third hydraulic flow, F3, to the at least one crane actuator via a third hydraulic conduit (310).

16. The cut-to-length logging harvester vehicle according to claim 15, comprising a second confluence valve (320) configured, when in the logfeeding mode, to, couple at least one of the regulated first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, to drive the crane.

17. The cut-to-length logging harvester vehicle according to any one of the preceding claims, comprising at least one electric motor (330) arranged in the vehicle frame and powered by at least one of: an electric energy storage unit (340) arranged in the vehicle frame, andGeneral - No protectionan electric generator (350) powered by an internal combustion engine (360), the electric generator and the internal combustion engine arranged in the vehicle frame, wherein at least one of the first hydraulic pump, the hydraulic power unit, and the third hydraulic pump is powered by the at least one electric motor.

18. A cut-to-length logging harvester head (130), comprising: a bar saw (140) operable in a log-cutting mode, said bar saw (140) having a saw bar (142), a saw chain (144), a saw bar positioner (146) configured to control a position of the bar saw, a log-feeding device (160) operable in a log-feeding mode, a first hydraulic actuator (150) arranged to receive a regulated first hydraulic flow, F1 , via a first hydraulic conduit (190) and configured, when the bar saw is in log-cutting mode, to mechanically drive the saw chain by the regulated first hydraulic flow, F1 , a first hydraulic interface (410) configured to connect to a cut-to- length logging harvester vehicle and to receive the regulated first hydraulic flow from a first hydraulic pump (180), wherein a speed of the saw chain has, when in the log-cutting mode, a proportional dependency on the first flow.

19. The cut-to-length logging harvester head according to claim 18, further comprising at least one second hydraulic actuator (170) configured to mechanically drive the log-feeding device, and wherein the log-feeding device, when in the log-feeding mode, is powered by at least one of the first hydraulic pump and a hydraulic power unit (200), wherein the hydraulic power unit is configured, when in log-feeding mode, to power the log-feeding device, by feeding a second hydraulic flow, F2, to the at least one second hydraulic actuator via a second hydraulic conduit (210).General - No protection5320. The cut-to-length logging harvester head according to claim 18 or 19, wherein the first hydraulic actuator is arranged to receive the regulated first hydraulic flow, F1 , from an external first hydraulic pump.21 . The cut-to-length logging harvester head according to any one of claims 19 to 20, wherein the at least one second hydraulic actuator is arranged to receive the second hydraulic flow, F2, from an external second hydraulic pump.

22. The cut-to-length logging harvester head according to any one of claims 19 to 21 , wherein the hydraulic power unit comprises at least one hydraulic accumulator (200b) configured to be pressurized by the regulated first hydraulic flow, F1 , and wherein the at least one hydraulic accumulator is configured to power the at least one second hydraulic actuator.

23. The cut-to-length logging harvester head according to any one of claims 19 to 22, comprising at least one of a harvester head rotator (132), harvester head clamps (134), and a harvester head filter (136), wherein the at least one second hydraulic actuator is configured, if the bar saw is in log-cutting mode, to drive at least one of the harvester head rotator, the harvester head clamps, and the harvester head filter, by the second hydraulic flow, F2.

24. The cut-to-length logging harvester head according to any one of claims 18 to 23, comprising braking means (260) configured to, when the bar saw is exiting log-cutting mode, reduce the speed of the saw chain, wherein the braking means comprises at least one of: a throttle valve configured to throttle the regulated first hydraulic flow, F1 , and a bypass valve configured to allow the regulated first hydraulic flow, F1 , to bypass the first hydraulic actuator, wherein the braking means is configured to be controlled based on atGeneral - No protection54 least one of: a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of harvester head clamps (134), and a hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.

25. The cut-to-length logging harvester head according to any one of claims 18 to 24, wherein the log-feeding device comprises feed rollers (530).

26. A cut-to-length logging harvester vehicle operating method (600), wherein the cut-to-length logging harvester vehicle comprises: a vehicle frame comprising a propulsion arrangement, a cut-to-length logging harvester head having a bar saw operable in a log-cutting mode, said bar saw having a saw bar, a saw chain, and a saw bar positioner configured to control a position of the bar saw, a log-feeding device operable in a log-feeding mode, and a first hydraulic actuator (150) configured to mechanically drive the saw chain (142), an articulated crane connected at its base side to the vehicle frame and connected at its tip side to the cut-to-length logging harvester head, a first hydraulic pump arranged at the base side and configured, when in the log-cutting mode, to control a speed of the saw chain towards a predetermined log-cutting speed by outputting a regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit extending between the base side and the tip side, and at least one second hydraulic actuator configured to mechanically drive the log-feeding device, the method comprising operating the cut-to-length logging harvester vehicle in the log-cutting mode or the log-feeding mode, wherein in the log-cutting mode the following is performed:General - No protection55 controlling (630) a speed of the saw chain by the first hydraulic pump via the regulated first hydraulic flow, F1 , based on a proportional dependency on the regulated first flow towards a predetermined log-cutting speed by outputting (610) a regulated first hydraulic flow, F1 , by the first hydraulic pump, and providing (620), the regulated first hydraulic flow, F1 , to the first hydraulic actuator via a first hydraulic conduit to drive the saw chain.

27. The cut-to-length logging harvester vehicle operating method according to claim 26, wherein the following is performed in the log-feeding mode: outputting (640) a first hydraulic flow, F1 , by a hydraulic power unit, and providing (650) the first hydraulic flow, F1 , to the at least one second hydraulic actuator via a second hydraulic conduit to power the log-feeding device.

28. The cut-to-length logging harvester vehicle operating method according to claim 27, wherein the hydraulic power unit comprises a second hydraulic pump arranged at the base side, and the harvester head comprises at least one of: a harvester head rotator, harvester head clamps, and a harvester head filter, and the operating method further comprises the following in the log cutting mode: outputting (665) the second hydraulic flow, F2, by the second hydraulic pump, and providing (680) the second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit, extendingGeneral - No protection56 between the base side and the tip side, to power at least one of the harvester head rotator, the harvester head clamps, the harvester head tilt, and the saw bar positioner.

29. The cut-to-length logging harvester vehicle operating method according to claim 27, wherein the hydraulic power unit is arranged in the harvester head and comprises at least one hydraulic accumulator configured to be pressurized by the first hydraulic pump, and the harvester head comprises at least one of: a harvester head rotator, harvester head clamps, and a harvester head filter, and the operating method further comprises the following in the log-cutting mode: outputting (667) the second hydraulic flow, F2, by the at least one hydraulic accumulator, providing (680) the second hydraulic flow, F2, to the at least one second hydraulic actuator via the second hydraulic conduit to power at least one of the harvester head rotator, the harvester head clamps, the harvester head filter, and the saw bar positioner.

30. The cut-to-length logging harvester vehicle operating method according to any one of claims 26 to 29, further comprising: reducing (690) the speed of the saw chain when the bar saw is exiting log-cutting mode by at least one of throttling (692) the first hydraulic flow, and bypassing (694) the first hydraulic actuator such that the regulated first hydraulic flow bypasses the first hydraulic actuator, and wherein reducing the speed of the saw chain is based on at least one of: a quantity indicative of the current saw chain speed; a current position of the saw bar positioner, a current position of harvester head clamps, and aGeneral - No protection57 hydraulic pressure of the regulated first hydraulic flow, F1 , in the harvester head.31 . The cut-to-length logging harvester vehicle operating method according to any one of claims 26 to 30, wherein the cut-to-length logging harvester vehicle comprises a first confluence valve, and the operating method further comprises: receiving (700) at least one operating condition, coupling (710), by the first confluence valve, the first hydraulic flow, F1 , and the second hydraulic flow, F2, to drive at least one of the log-feeding device, the harvester head rotator, the harvester head clamp means, and the harvester head tilt, based on the at least one operating condition.

32. The cut-to-length logging harvester vehicle operating method according to claim 31 , wherein the at least one operating condition comprises at least one of an operating mode of the cut-to-length logging harvester vehicle and an actuator condition of the at least one second hydraulic actuator.

33. The cut-to-length logging harvester vehicle operating method according to any one of claims 26 to 32, wherein the cut-to-length logging harvester vehicle comprises a third hydraulic pump arranged in the vehicle frame and at least one crane actuator configured to drive the crane, and the operating method further comprises: outputting (720) a third hydraulic flow, F3, by the third hydraulic pump, and providing (730) the third hydraulic flow, F3, to the crane actuator via a third hydraulic conduit to power the crane.

34. The cut-to-length logging harvester vehicle operating method according to any one of claims 26 to 33, wherein the cut-to-length logging harvesterGeneral - No protection58 vehicle comprises a second confluence valve, and the operating method further comprises: receiving (740) at least one operating condition, coupling (750), by the second confluence valve, at least one of the first hydraulic flow, F1 , and the second hydraulic flow, F2, with the third hydraulic flow, F3, to drive the crane, based on the at least one operating condition.

35. The cut-to-length logging harvester vehicle operating method according to any one of claims 26 to 34, wherein the cut-to-length logging harvester vehicle comprises a control unit, and the operating method further comprises, controlling (900), with the control unit, at least one of outputting the first hydraulic flow, F1 , by controlling the first hydraulic pump or controlling a power source configured to power the first hydraulic pump, outputting the second hydraulic flow, F2, by controlling the hydraulic power unit, outputting the third hydraulic flow, F3, by controlling the third hydraulic pump, coupling by the first confluence valve, and coupling by the second confluence valve.General - No protection

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