CABIN SUSPENSION SYSTEM

Abstract

A cabin suspension system, adapted to be used in a forestry vehicle, comprising an operator cabin, adapted to control the forest vehicle, spring dampers, mountable between the operator cabin and a vehicle frame, magnetorheological dampers, mountable between the operator cabin and a vehicle frame, sensors, adapted to detect velocity and/or acceleration and/or movement of the cabin, of the vehicle frame and a dampening coefficient of the magnetorheological dampers, and a controlling unit.

Claims

1. A cabin suspension system, adapted to be used in a forestry vehicle, the cabin suspension system comprising: an operator cabin adapted to control the forestry vehicle; a spring damper coupled to the operator cabin and a vehicle frame; a magnetorheological damper coupled to the operator cabin and the vehicle frame; a sensor adapted to detect at least one of a velocity, an acceleration, or a movement of at least one of the cabin or the vehicle frame and a dampening coefficient of the magnetorheological damper; and a controlling unit adapted for receiving and evaluating the sensor data; wherein the spring damper and the magnetorheological damper are adapted for acting in parallel between the vehicle frame and the operator cabin, and the controlling unit is adapted to monitor and regulate parameters of the magnetorheological damper so that movement, velocity, or acceleration of the operator cabin are controlled within a selectable parameter.

2. The cabin suspension system according to claim 1, wherein the operator cabin comprises a linkage so that the operator cabin movement is guided in an angular direction or a vertical direction.

3. The cabin suspension system according to claim 1, further comprising a roll over protection system that protects the operator cabin in case of a roll over situation of the forestry vehicle.

4. The cabin suspension system according to claim 1, wherein the magnetorheological damper and the spring damper have a travel length of 5 to 15 cm.

5. The cabin suspension system according to claim 1, wherein the parameters of the magnetorheological damper and the spring damper enable an angular movement of the operator cabin in relation to the vehicle frame of 2 to 5 degrees.

6. The cabin suspension system according to claim 1, wherein the roll over protection system enables transfer of forces from the operator cabin to the vehicle chassis during a roll over event.

7. The cabin suspension system according to claim 1, wherein the controlling unit controls power supply to the magnetorheological damper so that the dampening coefficient of the magnetorheological damper is adapted according to the measured sensor data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The detailed description of the drawings refers to the accompanying figures in which:

[0023] FIG. 1 depicts a forestry vehicle;

[0024] FIG. 2 shows an embodiment of the invention in a side view; and

[0025] FIG. 3 depicts an embodiment of the invention in a front view. Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Further embodiments of the invention may include any combination of features from one or more dependent claims, and such features may be incorporated, collectively or separately, into any independent claim.

DETAILED DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a forestry vehicle with an operator cabin 10. The vehicle comprises a front and rear chassis, which are rotatably connected. The front chassis usually carries the operator cabin 10 and a crane. The rear chassis carries the engine and power components. The operator cabin 10 is movably connected to the front chassis, so that the cabin 10 can rotate around a vertical axis and is able to be angled towards the ground to allow an upright operator position when the vehicle is positioned on slopes or generally steep off-road terrain.

[0027] The vehicle is used in off-road applications, moving over uneven ground with an irregular surface. Forest ground usually comprises of roots, rocks, hills, so that movement of the vehicle results in swinging movement of the vehicle in all directions. Bumpy terrain can also lead to larger amplitude of vibration and stronger movement.

[0028] The crane can be used to operate a harvesting head, for felling and cutting trees into logs. The operation of the crane involves grabbing a tree, cutting of the stem, bringing the tree in a horizontal orientation, so that the stem can be cut into pieces. All these operations involve different tasks with the crane and result in a change of the temporary center of gravity of the vehicle. These changes lead to tilt movement and swinging of the vehicle in a variable amount and at various times.

[0029] In another example, not shown here, a forwarder is used to transport the log pieces out of the forest area to the closest road system. The vehicle comprises two chassis parts with the operator cabin being on the front chassis and a load bunk being on a rear chassis. The vehicle comprises a crane for grabbing and loading the logs on the load space or bunk. The loading and unloading involves various changes to the center of gravity and lead to excitation, tilt movement and swinging movement of the vehicle.

[0030] The invention is therefore used to reduce all movements of the operator cabin that are transferred from the chassis to the cabin. With less movement and vibration, the operator is supported in safely controlling the vehicle. The operator is less exposed to the shocks so that operator fatigue and stress is also reduced resulting in better work environment.

[0031] FIG. 2 shows an embodiment in a side view. The cabin suspension system is mainly integrated in the cabin 10. The cabin 10 usually comprises doors for entering and front, rear and side windows. Inside the cabin 10, the operator uses control surfaces to control the operation of the vehicle. Below the cabin 10 are linkages 70, to enable a movable and rotatable connection to the chassis 30. The linkages 70 do not carry the weight of the cabin 10 but provide a guidance for the movement of the cabin 10 relative to the chassis 30.

[0032] The cabin 10 is further held with spring dampers 20 and magnetorheological dampers 40. The spring dampers 20 surround the magnetorheological dampers 40, but can also be provided in another manner, to have both kinds acting in parallel.

[0033] The spring dampers 20 have a fixed spring rate and a fixed dampening coefficient C. The magnetorheological dampers 40 allow the manipulation of the dampening coefficient C by setting a provided current to different levels. All dampers 20, 40 are provided at the front and rear of the cabin 10, preferably at all four corners. It is also possible to provide the dampers 20, 40 in different sizes, so that a reduced number of dampers 20, 40 can be provided. Such a setup could have to smaller spring dampers 20 and magnetorheological dampers 40 in the front, and one set of larger dampers in the back of the cabin 10.

[0034] The cabin 10 is also provided with sensors 50 which provide a feedback measurement of the movement of the cabin 10, such as linear and angular velocity and acceleration. The embodiment encloses one sensor 50 in the cabin 10, it is also possible to have multiple sensors 50 distributed in the cabin 10, such as in the front area and rear area of the cabin 10. This allows for measuring the values with more accuracy.

[0035] The cabin 10 is placed and connected on the vehicle chassis 30. In the present embodiment, the vehicle chassis 30 comprises of a connection platform and a roll over protection system 80. The roll over protection system 80 provides a pin, which limits the movement of the cabin in case of a roll over of the vehicle. More so the roll over protection system 80 prevents the cabin 10 from separating from the vehicle chassis 30. Another sensor 50 is provided on the vehicle chassis 30 to measure linear and angular velocity or acceleration.

[0036] Another sensor 50 may be provided on the magnetorheological dampers 40. This sensor 50 provides the angular and linear movement of the dampers 40, so that a feedback loop is created with the control unit 60. The control unit 60 is connected to all established sensors 50. The sensors 50 provide the local acceleration, velocity and movement. The control unit 60 processes the value data and determines a localized damping coefficient C for the magnetorheological dampers 40. In a next step, the control unit 60 sets a current resulting from the calculations and transmits the current to the magnetorheological dampers 40 so that the dampening coefficient C is adjusted. In response, the dampers 40 are providing an optimized dampening behavior for the situation of the vehicle and the movement of the cabin 10 to establish less movement and swinging of the operator.

[0037] FIG. 3 shows an embodiment in a front view of the cabin 10. FIG. 3 corresponds to FIG. 2 in that all features are disclosed in the front view. In addition to FIG. 2 it is shown that linkages 70 are also provided in a front and rear part of the cabin 10 to provide support on the vehicle chassis 30. Spring dampers 20 and magnetorheological dampers 40 are movably attached in a front section of the cabin 10 and the vehicle chassis 30 so that these can extend and compress without strain or bending. The roll over protection system 80 is provided under the cabin 10 on the vehicle chassis 30.

[0038] The sensors 50 are shown to be placed on the cabin 10 in a central area, yet, these can be placed also in a front and back area of the cabin, so as to receive multiple values for the control unit 60. Sensors 50 are also placed in front of the cabin 10 on the chassis 30. These as well can be place on multiple area on the chassis 30 so that more data is available for detecting the cabin 10 and chassis 30 movement and to control the magnetorheological dampers 40. The sensors 50 for the dampers 40 can be provided on one damper 40 alone or on multiple or all magnetorheological dampers 40. This enables a more accurate controllability of the dampening of the cabin 10.

[0039] The control unit 60 can be provided in the cabin 10, it may also be placed outside the cabin 10 or even on the chassis 30 to allow maintenance access from outside the vehicle. The control unit 60 is connected to the vehicle control unit so as to be controllable via the vehicle control surfaces, such as a touch panel or keyboard. The visualization is available by a screen for the operator. The operator can further make adjustments to the responsiveness of the suspension control system, so as to select the stiffness of the dampening control. This influences the control parameters of the dampening. The operator can also set the suspension control to automatic mode which provides a presetting for the suspension control for a wide range of terrain and work modes. The control unit 60 may be freely programmable to enable nonlinear behavior of the magnetorheological dampers 40. This would allow to change the dampening parameter during compression so as to realize a higher coefficient C at the beginning of a movement, which then further increases or the opposite so as to enable a unique and comfortable dampening behavior.

[0040] The suspension system is enabled by a controllable dampening coefficient C which avoid the provision of cameras so as to detect the terrain condition. The invention is highly adaptable and provides a suspension which has a low maintenance requirement. The avoidance of cameras which are susceptible to failure due to high vibration and the off road environment enable the use of the suspension in all conditions and temperatures.