Method for controlling a winch assembly of a piste caterpillar, piste caterpillar with device for carrying out said method

Abstract

A method and device for controlling a winch assembly (1) of a snow groomer (2), wherein the winch assembly comprises a winch cable and a winch arm (4) guiding the winch cable (3), which is rotatably mounted about a vehicle vertical axis (FH), is disclosed. The method comprises the following steps: - detecting a change in the cable tension of the winch cable during winch operation of the winch assembly, - specifying a setpoint range for the operational cable tension, - specifying a limit value for the change in cable tension, - comparing the detected change in cable tension of the winch cable with the specified limit value, and - controlling a rotary drive associated with the winch arm, taking the comparison into account, such that if the limit value for the change in cable tension is undershot, the operational cable tension is at least largely approximated to the specified setpoint range by an active compensatory rotary movement of the winch arm.

Description

SCOPE OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a method for controlling a winch arrangement of a snow groomer, wherein the winch arrangement comprises a winch cable and a winch arm guiding the winch cable, which is rotatably mounted about a vehicle vertical axis.The invention further relates to a snow groomer with a device for carrying out such a method comprising: a winch arrangement with a winding device for storing and winding the winch cable, which can be anchored at a free end area facing away from the winding device with a stationary anchor point; a drive device associated with the winding device for introducing tensile forces onto the winch cable; a winch arm for feeding the winch cable to the winding device, wherein the winch arm is rotatably mounted about a vehicle vertical axis, and a rotary drive associated with the winch arm for generating active rotary movements of the winch arm about the vehicle vertical axis; and a control device for controlling the rotary drive of the winch arm.

[0002] A device described above is known from the applicant's product range and is used for snow groomers marketed by the applicant under the brand name "Pistenbully" for maintaining and preparing steep ski slopes. The known device comprises a winch assembly rotatably mounted on the snow groomer's chassis about a vertical axis and includes a winding device designed as a cable drum. A drive unit for a winch cable is associated with the winding device, enabling the cable to be wound onto or unwound from the cable drum.In the known winch arrangement, a steel cable is used as the flexible winch cable. A locking device, designed as a hook similar to a crane hook and secured with a snap lock, is attached to one of the free ends of the steel cable, which faces away from the winding device. The winch arrangement is equipped with a guide device, typically designed as a boom or winch arm with cable guides, which is intended for feeding the winch cable to the drive unit. The winch arm allows the winch cable to be guided from the winding device over the cab of the snow groomer, so that the snow groomer operator has the winch cable in their field of vision, at least during the main operating conditions when the snow groomer is facing uphill.Furthermore, the winch arm can be designed to guide the winch cable in a predetermined direction relative to the snow groomer, thus ensuring optimal application of the tensile forces transmitted by the winch cable to the snow groomer. For this purpose, the winch assembly incorporates a rotary drive to position the winch arm laterally and / or to actively improve the vehicle's steering response through a rotational movement.

[0003] For traversing and grooming steep snow-covered terrain, the winch cable is unwound from the winding mechanism and anchored or fixed to a stationary anchor point in an upper area of ​​the terrain. The snow groomer then traverses the slope with traction assistance provided by the taut winch cable, which is wound and unwound by the winding mechanism and its drive system, depending on the groomer's position and speed. This traction-assisted operation of the snow groomer is referred to as winch operation. Among other things, winch operation enables the groomer to prepare steep terrain that would otherwise be inaccessible.

[0004] During winch operation of the snow groomer, it can happen that the winch cable temporarily becomes temporarily fixed to a terrain contour or a surface on the ski slope, such as a hilltop or snowdrift, with a lateral offset from the direct uphill alignment or track of the snow groomer towards the stationary anchor point. This situation can occur, for example, if a different track is chosen for the ascent than for the descent. In this situation, the winch arm, due to its floating, rotating bearing, is deflected to the side or in the direction of the temporary fixation point. This results in enormous tension in the winch cable. If the frictional force between the winch cable and the surface at the temporary fixation point becomes sufficiently low, e.g.,Because the snow groomer is moving uphill towards the anchor point, or due to a lateral movement, the winch cable suddenly springs free from its temporary fixation, moving directly between the snow groomer and the stationary anchor point. This is often referred to as cable slap. When the winch cable springs free, extreme stresses occur in the cable due to its high static tension. This results in high dynamic inertial forces, particularly longitudinal and transverse forces, which are transmitted through the winch cable to the snow groomer's winch assembly, thus shortening the service life of both the winch cable and the winch assembly, especially the winch arm. Furthermore, there is a risk of negative forces acting on the snow groomer itself, potentially compromising safe operation.Furthermore, the difficulty can arise that, due to a sudden drop in winch cable tension, the unstretched winch cable lies on the ground or ski slope in front of the snow groomer and is run over by the snow groomer.

[0005] A method disclosed in German patent application DE 10 2007 061 110 A1 provides for the arrangement of a mechanical and / or hydraulic compensator at a stationary anchor point for attaching the winch cable of a snow groomer. The compensator dampens longitudinal and transverse vibrations occurring in the winch cable and absorbs peak loads in the winch cable, i.e., between the winch and the anchor point, and thus also the winch. Furthermore, a device is disclosed that is a mechanical and / or hydraulic compensator designed to absorb and dampen impact loads exceeding the normal load during slope operation caused by freely flapping cables. The compensator is arranged as a link between an anchoring device for the winch cable and the anchor point.

[0006] Patent EP 2 398 966 B1 discloses a snow groomer with a winch assembly for facilitating its handling on steep slopes. The snow groomer comprises a control unit and the winch assembly, which includes a rotatably mounted drum, a winch cable wound around the drum, an actuator assembly for rotating the drum, a first sensor for determining the drum's position, a roller rotated by the winch cable, and a second sensor for determining the roller's position. The control unit is configured to detect the drum's rotational speed and the roller's rotational speed and to control the actuator assembly as a function of the drum's rotational speed, the roller's rotational speed, the drum's position, and the geometry of the roller and drum, in order to control the winch cable tension.

[0007] The German patent application EP 1 118 580 A1 discloses a device for the automatic adjustment and control of the pulling force of the cable of a winch assembly for a snow groomer. The device comprises a control unit connected to a steerable winch drive, and an evaluation unit connected to sensor elements and to the control unit. The sensor elements are pressure sensors that detect the highest pressure present at a changeover valve located between the feed lines of right- and left-hand drives in a first direction of travel and in a direction opposite to the latter. The evaluation unit contains an algorithm that calculates a setpoint based on the pressure value obtained from the pressure sensors, which then controls the winch drive via the control unit.This setpoint is compared with an actual value measured by means of a force pin attached to the winch cable, and the control unit adjusts the pulling force to the setpoint. The system also includes a rotary encoder that determines the angle of the winch cable or winch arm relative to the vehicle's longitudinal axis, generating a signal proportional to the angle. This signal is then sent to the evaluation unit to calculate the maximum permissible pulling force.

[0008] A method and a snow groomer according to the preamble of claim 1 and 9 respectively are known from EP 2 554 750 A2. TASK AND SOLUTION

[0009] The object of the invention is to create a method, a device and a snow groomer of the type mentioned above that enable a high level of operational reliability.

[0010] This problem is solved for the method by the features of claim 1 and for the snow groomer by the features of claim 9. Advantageous further developments and / or embodiments of the invention are specified in the dependent claims, the wording of which is hereby incorporated into the description by reference. This includes, in particular, all embodiments of the invention that result from the combinations of features defined by the cross-references in the dependent claims.

[0011] The inventive method for controlling a winch arrangement of a snow groomer comprises the following steps: Detecting a change in the rope tension of the winch rope during winch operation of the winch arrangement, specifying a target value range for operational rope tension, specifying a limit value for the rope tension change, comparing the detected rope tension change of the winch rope with the specified limit value and controlling a rotary drive assigned to the winch arm, taking into account the comparison in such a way that, if the limit value for the rope tension change is undershot, the operational rope tension is at least as close as possible to the specified target value range by means of an active compensating rotary movement of the winch arm.

[0012] The inventive method allows for the early detection of cable slippage during winch operation of the snow groomer. Through an active compensating rotational movement of the winch arm, the operational cable tension can be at least largely restored or even nearly maintained. This minimizes the mechanical stress on the winch cable, the winch assembly, and the snow groomer, thereby increasing operational reliability.

[0013] When measuring the change in winch cable tension during winch operation, the rotary drive associated with the winch arm is initially passive or deactivated. With a passive rotary drive, the winch arm is positioned floating around the vehicle's vertical axis and thus freely rotatable. Measuring a change in winch cable tension requires time-dependent measurement of the cable tension using generally known methods. The change in winch cable tension serves as a control variable and can, for example, be defined by a change in the tensile force of the winch cable over a predetermined time period. Such a value is preferably determined empirically.

[0014] The specified target range for the operational rope tension defines a rope tension range within which, under the given operating conditions, the winch rope is taut and does not sag. The specified limit value for the rope tension change indicates a value below which a rope slap or a sudden decrease in winch rope tension is to be expected.

[0015] The time-dependent change in winch rope tension is compared to the predefined limit value. If the rope tension falls below the limit value, the rotary drive associated with the winch arm is activated. This drive initiates a compensatory rotation of the winch arm, ensuring that the actual value of the operational rope tension is at least as close as possible to, or even reaches, the predefined target value. The actual value of the operational rope tension is also recorded during this compensatory rotation. This compensatory rotation of the winch arm is actively initiated by the rotary drive of the winch assembly or winch arm and is therefore also referred to as an active compensatory rotation. In contrast, a passive (floating) rotation of the winch arm occurs when the rotary drive is deactivated and the freely rotatable winch arm is, for example, not mounted on a bearing.The winch arm is rotated by a tensile force applied to it. The winch arm can be mounted separately to rotate or mounted to rotate together with a support structure of the winch assembly.

[0016] The inventive method for controlling a winch arrangement of a snow groomer is particularly advantageous for maintaining and preparing steep ski slopes using winch operation.

[0017] In a further development of the invention, the method comprises the following additional steps: Detecting a change in the rotational position of the winch arm during winch operation of the winch arrangement, specifying a limit value for the change in rotational position, comparing the detected change in rotational position of the winch arm with the specified limit value, and controlling the rotary drive assigned to the winch arm, taking this comparison into additional consideration, such that if the limit value for the change in rotational position is exceeded by the active compensating rotary movement of the winch arm, the operational rope tension is at least as close as possible to the specified target value range.

[0018] One advantage of this design is that a rope slap or a sudden decrease in rope tension can be detected even earlier and more reliably. The change in the rotational position of the winch arm can be caused by a rope slap, i.e., by the winch rope suddenly snapping out of its temporary fixation on a slope being prepared.

[0019] Detecting a change in the winch arm's rotational position during winch operation occurs simultaneously with detecting a change in cable tension, so the rotary drive is initially deactivated. Consequently, the winch arm is freely rotatable around the vehicle's vertical axis. Detecting a change in the winch arm's rotational position also requires time-dependent measurement of the arm's position using generally known methods. The change in the winch arm's rotational position can be defined as a change in its angle of rotation relative to a vehicle's longitudinal axis over a predefined time interval. This change can be measured as either the angular velocity or the angular acceleration. The predefined limit value for the change in rotational position specifies a value beyond which a cable slap or a sudden decrease in winch cable tension is assumed.It is possible to specify multiple limit values ​​for a corresponding angular velocity and / or a corresponding angular acceleration.

[0020] The time-dependent change in the rotational position of the winch arm is compared with the predefined limit value for the change in rotational position. This comparison is considered in addition to the comparison of the recorded change in winch cable tension with the predefined limit value for the change in cable tension, as described above. This means that the rotary drive associated with the winch arm is only activated to compensate for the change in rotational position by means of a rotary movement of the winch arm, thereby approximating the actual value of the operational cable tension to the predefined target value range as closely as possible, if both the limit value for the change in rotational position and the limit value for the change in cable tension are exceeded, particularly simultaneously.If several limit values ​​are specified for the angular velocity and the angular acceleration, the rotary drive is preferably activated when a first limit value is exceeded.

[0021] In one embodiment of the invention, the active compensating rotational movement of the winch arm occurs in the same or opposite direction to the change in the winch arm's rotational position. The change in the winch arm's rotational position is a passive rotational movement and can occur in a specific direction depending on the winch arm's rotational position and the direction of travel of the snow groomer. The active compensating rotational movement of the winch arm then occurs either in the same or opposite direction to this rotational movement.

[0022] If the active compensation rotation movement is in the opposite direction to the change in the rotational position of the winch arm, the passive rotation movement of the winch arm is slowed and / or stopped by controlling the rotary drive and then rotated in the opposite direction until the actual value of the operational rope tension is within the specified target value range or at least approaches it as closely as possible.

[0023] If the active compensation rotation movement occurs in the same direction, then the passive rotation movement of the winch arm caused by the decrease in the winch rope tension is not initially slowed or stopped by activating the rotary drive, but is rotated further in the same direction until the actual value of the operational rope tension is within the specified target value range or at least approaches it as closely as possible.

[0024] In one embodiment of the invention, the angle of rotation of the winch arm relative to a longitudinal axis of the vehicle is detected, and this angle is taken into account when detecting the change in the rotational position of the winch arm during winch operation of the winch assembly. The detection of the angle of rotation of the winch arm can be carried out using generally known measuring methods.

[0025] In a further development of the invention, a tensile force on the winch assembly is measured over time to detect the change in rope tension of the winch rope during winch operation. The tensile force on the winch assembly can be measured at a front end region of the winch arm using generally known measuring methods.

[0026] In a further development of the invention, the active compensating rotational movement of the winch arm relative to a plane defined by the vehicle's vertical axis and a stationary anchor point of the winch cable occurs within an angular range of 0° to 90°. This means that the active compensating rotational movement relative to the defined plane occurs within an angular range of -90° to +90°. In the plane defined by the vehicle's vertical axis and the stationary anchor point of the winch cable, there is a straight and therefore direct connection between the winch arm and the stationary anchor point. If the winch arm lies in this plane, then the winch cable anchored to the stationary anchor point also lies in this plane.

[0027] In a further development of the invention, the method after the active compensation rotational movement of the winch arm includes the following additional step: Controlling the rotary drive in such a way that the winch arm aligns itself towards a plane defined by the vehicle's vertical axis and a stationary anchor point of the winch cable through an active return movement, taking into account the target value range for the operational cable tension.

[0028] Actuating the rotary drive is equivalent to reversing its direction of rotation, as the active return movement of the winch arm is opposite to its active compensating rotation. By adjusting the snow groomer's travel speed and / or the winch cable winding speed, the cable tension can be further controlled and preferably maintained within the target range for the operational cable tension. After the active return movement of the winch arm, both the tensioned winch cable and the winch arm itself lie in the aforementioned tensioned plane and thus in direct alignment with the stationary anchor point.

[0029] In one embodiment of the invention, the method includes the following further step after the active return movement of the winch arm: Controlling the rotary drive in such a way that it releases the rotation of the winch arm.

[0030] Actuating the rotary drive here is equivalent to deactivating it. While the rotary drive preferably remains mechanically connected to the winch arm, it is switched to a virtually pressureless rotation. This means that after this step, the winch arm is again freely rotatable, in particular with essentially no resistance, and aligns itself depending on the tensile force acting on the winch cable between the anchor point and the winch arm.

[0031] The snow groomer according to the invention, with a device for carrying out the method, is provided with sensors for detecting changes in the winch cable tension during winch operation. Furthermore, an electronic data processing system is provided, which includes a data storage unit containing the target value range for operational cable tension and the limit value for cable tension changes. This system is coupled to the sensors to control the rotary drive's control unit when the cable tension falls below the limit value. This control unit then uses an active compensating rotary movement of the winch arm to bring the operational cable tension at least as close as possible to the specified target value range.

[0032] The sensors for detecting changes in winch cable tension are designed for time-dependent measurement of the cable tension. For this purpose, the sensors may include or be associated with a time recording unit. The sensors, particularly the time recording unit, allow the recorded data to be assigned to different points in time or time periods. This enables the calculation of a cable lash pattern in relation to corresponding changes in winch cable tension. By extrapolating this pattern into the future, a predictive model for cable lash can be derived. The data processing system has access to the data stored in the data memory, including the target value range for operational cable tension and the limit value, which is then compared with the data recorded by the sensors.

[0033] The solution according to the invention is suitable for winch arrangements in which the winch arm is fixed to the winch assembly. In such a design, the winch arm, together with the winch assembly or the winding device, is rotatably mounted on the snow groomer. However, the solution according to the invention can also be used in winch arrangements in which the winding device for the winch cable is fixed to the vehicle. In these winch arrangements, the winch arm itself is rotatably mounted relative to the vehicle-fixed winding device.

[0034] In a further development of the invention, the device is equipped with additional sensors for detecting changes in the rotational position of the winch arm during winch operation. Furthermore, the data processing system includes a data storage unit in which the limit value for the change in rotational position is stored and is coupled to the additional sensors. When this limit value is exceeded, the control unit of the rotary drive is activated in such a way that the operational rope tension is brought at least as close as possible to the specified target value range by means of the active compensating rotational movement of the winch arm. This represents a structurally and functionally advantageous implementation of the device.

[0035] The additional sensors for detecting changes in the winch arm's rotational position are designed for time-dependent detection of the winch arm's rotational position. These additional sensors can include, or be associated with, a time-detection unit as described above. The data acquired by these sensors can also be considered in the predictive model for a rope strike. The data processing system has access to the data stored in the data memory regarding the target value range for operational rope tension and the limit value, which is then compared with the data acquired by the additional sensors.

[0036] In a further development of the invention, the additional sensor system for detecting the rotational position of the winch arm includes a rotation angle sensor, which is designed to detect a rotation angle of the winch arm relative to a longitudinal axis of the vehicle.

[0037] In a further development of the invention, the sensor system for detecting the rope tension of the winch rope is arranged in the winch arm, in particular at a front end region of the winch arm, and / or has a tensile force sensor for detecting a tensile force on the winch assembly.

[0038] A snow groomer according to the invention exhibits a significantly increased operational reliability in winch operation, both with regard to the driving function and the winch function, as well as the functions of the attachments.

[0039] A preferred embodiment of the invention is shown in the drawings. This and further embodiments of the invention are explained in more detail below. The drawings show: Fig. 1 schematically shows a snow groomer in a side view with a device for controlling a winch arrangement; Fig. 2 schematically shows the snow groomer in a side view according to the Fig. 1 In winch operation with a winch arm aligned with a stationary anchor point and an anchored winch cable, Figs. 3A and 3B schematically in a top view the snow groomer according to the Fig. 2 with different directions of travel of the snow groomer relative to the anchor point, Fig. 4 schematically in a side view the snow groomer according to the Fig. 2 with a temporary fixing point of the winch cable and Fig. 5A to 5D schematically in a top view the temporal sequence of the inventive method for controlling the winch arrangement of the snow groomer.

[0040] A snow groomer 2 after Fig. 1 The snow groomer 2 features a tracked undercarriage 18, which is assigned to a chassis not further specified, in a generally known manner. The chassis carries a driver's cab 19 at the front. A snowplow blade 20 is provided as a front attachment. A rear-mounted rotary tiller 21 is provided as a rear attachment, which is adjustable and detachably held on the chassis of the snow groomer 2 via a rear implement carrier not further specified.

[0041] The snow groomer 2 further comprises a device for controlling a winch assembly 1 of the snow groomer 2. The winch assembly 1 is rotatably mounted on the chassis of the snow groomer 2 about a vehicle vertical axis FH, preferably via a ball-bearing slewing ring, and comprises a winding device 6 to which a drive unit 8 for a winch cable 3 is assigned for applying a tensile force FZ to the winch cable 3, wherein the winch cable 3 can be wound onto or unwound from the winding device 6. The winch cable 3 has an unspecified locking device, preferably a hook, at a free end region 7 facing away from the winding device 6, by means of which the winch cable 3 can be anchored to a stationary anchor point A, as is shown in particular in the Fig. 2 The winch assembly 1 further comprises a winch arm 4 for feeding the winch cable 3 to the winding device 6. The winch arm 4 enables the winch cable 3 to be guided over a driver's cab 19 of the snow groomer 2, so that a driver of the snow groomer 2 has the winch cable 3 in their field of vision, at least when the snow groomer 2 is oriented uphill, as shown in the Fig. 2 The winch assembly 1 further comprises a rotary drive 5 for generating active rotary movements of the winch assembly 1 or the winch arm 4 about the vehicle's vertical axis FH. In this case, the rotary drive 5 is preferably designed as an electric or hydraulic motor. The snow groomer 2 has a control unit 9 for controlling the rotary drive 5 of the winch assembly 1 or the winch arm 4, wherein the rotary drive 5 preferably acts via a pinion on a toothed section provided on the winch assembly 1, which is at least partially rotating. This enables an active rotary movement of the winch assembly 1 or the winch arm 4. The toothed section is coplanar to a plane of the slewing ring. The slewing ring is preferably located in a horizontal plane.

[0042] The snow groomer 2, or rather the device for controlling the winch assembly 1 of the snow groomer 2, further comprises a sensor 10 for detecting a change in the rope tension of the winch rope 3 during winch operation of the winch assembly 1. In addition, an electronic data processing system 11 is provided, which includes a data storage device 12 in which the data of a target value range for an operational rope tension and a limit value for the rope tension change are stored. The electronic data processing system 11 is coupled to the sensor 10 in order to instruct the control unit 9 of the rotary drive 5, if the limit value for the rope tension change is undershot, such that the operational rope tension is brought as close as possible to a predetermined target value range by means of an active compensatory rotary movement of the winch assembly 1 or the winch arm 4.

[0043] In the Fig. 2 The snow groomer 2 is shown on a steep ski slope P in winch operation, traveling uphill (FR). In winch operation, the snow groomer 2 is anchored to the stationary anchor point A at the free end 7 of the winch cable 3, which is opposite the winding device 6. This allows the snow groomer 2 to traverse the slope with traction provided by the tensioned winch cable 3. The stationary anchor point A is a post anchored in the ground and is located above the ski slope P.

[0044] The Fig. 3A und 3B Figure 2 shows a top view of the snow groomer 2 with different directions of travel FR of the snow groomer 2 relative to the stationary anchor point A. The rotation of the winch assembly 1 or the winch arm 4 of the snow groomer 2 is enabled by the rotary drive 5. This means that the rotary drive 5 remains mechanically connected to the winch arm 4, but is switched to a virtually pressureless rotation. Therefore, due to its free, essentially resistance-free rotation, the winch arm 4 aligns itself in the direction of a tensile force FZ of the winch cable 3 or towards the stationary anchor point A. The winch arm 4 lies in a plane E defined by the vehicle's vertical axis FH and the stationary anchor point A of the winch cable 3. Fig. 3A The direction of travel FR, or a direct track of the snow groomer 2, aligns with the stationary anchor point A. In this situation, the winch assembly 1, or rather the winch arm 4 of the snow groomer 2, is in its neutral position. This means that the winch arm 4 runs along the longitudinal axis FL of the vehicle, or in the direction of travel FR of the snow groomer 2. Fig. 3B The stationary anchor point A is laterally offset to the direction of travel FR or the direct track of the snow groomer 2. In this situation, the winch assembly 1 or the winch arm 4 of the snow groomer 2 aligns itself with the laterally offset anchor point A and rotates relative to the zero position or the vehicle's longitudinal axis FL by the angle of rotation α. Fig. 4 Figure 1 shows a side view of plane E, defined by the vertical axis FH of the snow groomer 2 and the stationary anchor point A of the winch cable 3. A straight line connects the winch arm 4 (or the vertical axis FH) and the stationary anchor point A within plane E.

[0045] In the Fig. 4 A temporary fixing point T of the winch cable 3 is also shown. The temporary fixing point T of the winch cable 3 arises in particular when the winch cable 3 is temporarily fixed to a terrain contour or a snow surface elevation of a ski slope P with a lateral offset to the direct alignment or plane E of the snow groomer 2, as is also shown in the Fig. 5A As can be seen, the winch assembly 1, or rather the winch arm 4, is deflected to the side or in the direction of the temporary fixing point T due to the rotatable bearing. If the winch cable 3 releases from its temporary fixing point T, it snaps abruptly in a direct direction between the snow groomer 2 and the stationary anchor point A, or in the direction of the plane E, due to static pretension forces on the winch cable 3, as shown in the figure. Fig. 5B This is evident. This will also be referred to as the rope lay in the following. The winch arm 3 rotates with the winch rope 3 in this direct direction.

[0046] The Fig. 5A bis 5D The figures show in a top view the temporal sequence of the inventive method for controlling the winch arrangement 1 of the snow groomer 2. In the example shown, the stationary anchor point A is not in line with the vehicle's longitudinal axis FL or the direction of travel FR of the snow groomer 2, so that the vehicle's longitudinal axis FL does not lie in the plane E, as is particularly evident in the Fig. 5A This is evident. Furthermore, as already mentioned, the temporary fixing point T is neither aligned with the vehicle's longitudinal axis FL or the direction of travel FR of the snow groomer 2, nor with the plane E.

[0047] If a rope lash occurs during winch operation of the winch assembly 1, this leads to a change in the rope tension of the winch rope 3. This change in rope tension of the winch rope 3 is detected by the sensor 10. The electronic data processing system 11 specifies a target value range for operational rope tension and a limit value for the rope tension change, with this data being stored on a data storage device 12. The data processing system 11 compares the detected rope tension change of the winch rope 3 with the specified limit value. If the detected rope tension change of the winch rope 3 falls below the limit value, the data processing system 11 instructs the control unit 9 of the rotary drive 5 such that an active compensating rotary movement of the winch assembly 1 or the drive unit 5 is initiated.of the winch arm 4, the operational rope tension approximates at least as closely as possible to a specified target value range.

[0048] In an advantageous embodiment, the device for controlling the winch assembly 1 of the snow groomer 2 includes further sensors 13 for detecting a change in the rotational position of the winch arm 4 during winch operation of the winch assembly 1. This is because, as described above, during a cable pull, the freely rotatable winch arm 4 is turned in the direction of plane E, as shown in the Fig. 5B As can be seen, the data processing system 11 specifies a limit value for the change in rotational position, which is stored in an assigned data memory 14. For this purpose, the data processing system 11 is coupled with the additional sensor system 13. The data processing system 11 compares the detected change in rotational position of the winch arm 4 with the specified limit value. This comparison is taken into account in addition to the previously mentioned comparison of the detected change in rope tension of the winch rope 3 with the specified limit value.

[0049] In other words: If the detected change in rope tension of the winch rope 3 falls below the specified limit value and the change in rotational position of the winch arm 4 exceeds the specified limit value, then the data processing system 11 instructs the control unit 9 of the rotary drive 5 such that, through an active compensating rotational movement of the winch assembly 1 or the winch arm 4, the operational rope tension approaches a specified target value range as closely as possible. In the example shown, the operational rope tension has reached the specified target value range. The winch rope 3 is in a tensioned state between the winch arm 4 and the stationary anchor point A, as shown in the Fig. 5C as is evident.

[0050] In an advantageous embodiment, as in the example shown, the active compensating rotational movement of the winch arm 4 occurs in the opposite direction to the change in the rotational position of the winch arm 4. In the Fig. 5B A passive rotational movement of the winch arm 4 in a direction of rotation DR is shown. In this embodiment, the direction of rotation DR of the passive rotational movement of the winch arm 4 corresponds to a counterclockwise direction. The passive rotational movement of the winch arm 4 is braked or stopped by actuating or activating the rotary drive 5 and then rotated in the opposite direction. The counterclockwise rotational movement of the winch arm 4 preferably tensions the winch cable 3. Thus, in the example shown, the active compensating rotational movement of the winch arm 4 is clockwise.

[0051] In alternative versions, the active compensation rotational movement of the winch arm 4 is in the same direction as the change in the rotational position of the winch arm 4.

[0052] In advantageous embodiments, a rotation angle α of the winch arm 4 relative to a vehicle longitudinal axis FL is detected, as shown in the Fig. 3B The rotation angle α is taken into account when detecting the change in the rotational position of the winch arm 4 during winch operation of the winch arrangement 1. For this purpose, the additional sensor 13 for detecting the rotational position of the winch arm 4 includes a rotation angle sensor 15, which is designed to detect a rotation angle α of the winch arrangement 1 or of the winch arm 4 relative to a longitudinal axis FL of the vehicle.

[0053] In an advantageous embodiment, the tensile force FZ on the winch assembly 1 is detected over time and taken into account when detecting the change in tension of the winch cable 3 during winch operation. For this purpose, the sensor 10 for detecting the tension of the winch cable 3 is arranged in the winch arm 4, particularly at a front end region 16 of the winch arm 4, and / or includes a tensile force sensor 17 for detecting the tensile force FZ on the winch assembly 1. In the illustrated embodiment, the tensile force sensor 17 is arranged on a deflection pulley 22 at the front end region 16 of the winch arm 4, as shown in the Fig. 1 As can be seen, a further deflection pulley 23 is arranged downstream of the deflection pulley 22, starting from the winch arrangement 1 and extending towards the front end region 16, so that the detection of the tractive force FZ takes place at the second deflection pulley 22 of the winch arm 4, as seen from the front end region 16 of the winch arm 4.

[0054] In further advantageous embodiments, the active compensation rotational movement of the winch arm 4 relative to the plane E defined by the vehicle's vertical axis FH and the stationary anchor point A of the winch cable 3 takes place within an angular range β between 0° and 90°. That is, the active compensation rotational movement of the winch arm 4 takes place relative to the defined plane E within an angular range of -90° to +90°, as shown in the Fig. 5A as is evident.

[0055] In an advantageous implementation, after the active compensation rotation of the winch arm 4, the rotary drive 5 of the winch arrangement 1 or of the winch arm 4 is controlled such that the winch arm 4 aligns itself towards the plane E by means of an active return movement, taking into account the setpoint range for the operational rope tension, as shown in the Fig. 5DThis is evident. By adjusting or reducing the travel speed of the snow groomer 2 and / or by adjusting or increasing the winding speed or rotation speed of the winding device 6 of the winch cable 3, the cable tension can be maintained within the target range for the operational cable tension of the winch cable 3. After the active return movement of the winch arm 4, both the tensioned winch cable 3 and the winch arm 4 itself lie in plane E and thus in direct alignment with the stationary anchor point A. Since the stationary anchor point A is not in line with the longitudinal axis FL of the snow groomer 2, the winch arm 4 is slightly rotated relative to the longitudinal axis FL.

[0056] In advantageous embodiments, after the active return movement of the winch arm 4, the rotary drive 5 of the winch assembly 1 or of the winch arm 4 is controlled such that it releases the rotatability of the winch arm 4. The winch assembly 1 or of the winch arm 4 is then freely rotatable again.

Claims

1. A method for controlling a winch assembly (1) of a snow groomer (2), wherein the winch assembly (1) has a winch cable (3) and a winch arm (4) guiding said winch cable (3) and mounted rotatably about a vertical vehicle axis (FH), with the following steps: - Detecting a change in a cable tension of the winch cable (3) in a winching operation of the winch assembly (1), - Presetting a set value range for an operational cable tension, characterized by the steps: - Presetting a limit value for the cable tension change, - Comparing the detected cable tension change of the winch cable (3) with the set limit value and - Controlling a rotary drive (5) associated with the winch arm (4), taking the comparison into account, such that if the limit value for the cable tension change is not reached, the operational cable tension is brought at least largely close to the preset set value range by an active compensatory rotary movement of the winch arm (4).

2. The method according to claim 1, further characterized in that the method has the following steps: - Detecting a change in a rotary position of the winch arm (4) during the winching operation of the winch assembly (1), - Presetting a limit value for the rotary position change, - Comparing the detected rotary position change of the winch arm (4) with the preset limit value and - Controlling the rotary drive (5) associated with the winch arm (4), additionally taking the comparison into account, such that if the limit value for the rotary position change is exceeded, the operational cable tension is brought at least largely close to the preset set value range by the active compensatory rotary movement of the winch arm (4).

3. The method according to claim 2, further characterized in that the active compensatory rotary movement of the winch arm (4) is in the same direction or the opposite direction to the rotary position change of the winch arm (4).

4. The method according to either of claims 2 or 3, further characterized in that a rotation angle (α) of the winch arm (4) relative to a longitudinal vehicle axis (FL) is detected and is taken into account when detecting the rotary position change of the winch arm (4) during the winching operation of the winch assembly (1).

5. The method according to any of the previous claims, further characterized in that a tensile force (FZ) is detected time-dependently at the winch assembly (1) for detecting the cable tension change in the winch cable (3) during the winching operation of the winch assembly (1).

6. The method according to any of the previous claims, further characterized in that the active compensatory rotary movement of the winch arm (4) relative to a plane (E) created by the vertical vehicle axis (FH) and by a stationary anchor point (A) of the winch cable (3) is performed in an angle range (β) of between 0° and 90°.

7. The method according to any of the previous claims, further characterized in that the method has, after the active compensatory rotary movement of the winch arm (4), the following further step: - Controlling the rotary drive (5) such that the winch arm (4) aligns itself, by an active rearward movement, taking into account the set value range for the operational cable tension, with a plane (E) created by the vertical vehicle axis (FH) and by a stationary anchor point (A) of the winch cable (3).

8. The method according to claim 7, further characterized in that the method has, after the active rearward movement of the winch arm, the following further step: - Controlling the rotary drive (5) such that it enables rotatability of the winch arm (4).

9. A snow groomer with a device for performing a method according to at least one of the previous claims 1 to 8, having: - a winch assembly (1) with - a winding device (6) for storing and winding up the winch cable (3), which cable is anchorable to a free end region (7), facing away from the winding device (6), with a stationary anchor point (A), - a drive device (8) associated with the winding device (6) for introducing tensile forces (FZ) onto the winch cable (3), - a winch arm (4) for feeding the winch cable (2) to the winding device (6), wherein the winch arm (4) is mounted rotatably about a vertical vehicle axis (FH) and - a rotary drive (5) associated with the winch arm (4) for generating active rotary movements of the winch arm (4) about the vertical vehicle axis (FH), and - a control device (9) for controlling the rotary drive (5) of the winch arm (4), wherein - a sensor system (10) is provided for detecting a cable tension change in the winch cable (3) during the winching operation of the winch assembly (1) and - an electronic data processing system (11) is provided that has a data memory (12) in which the data of the set value range for an operational cable tension and the limit value for the cable tension change are stored, and which is coupled to the sensor system (10) in order to control, if the limit value for the cable tension change is not reached, the control device (9) of the rotary drive (5) such that the operational cable tension is brought at least largely close to the preset set value range by an active compensatory rotary movement of the winch arm (4).

10. The snow groomer according to claim 9, further characterized in that - a further sensor system (13) is provided for detecting a rotary position change of the winch arm (4) during the winching operation of the winch assembly (1), and - the data processing system (11) has a data memory (14) in which the limit value for the rotary position change is stored and which is coupled to the further sensor system (13) in order to control, if the limit value for the rotary position change is exceeded, the control device (9) of the rotary drive (5) such that the operational cable tension is brought at least largely close to the preset set value range by an active compensatory rotary movement of the winch arm (4).

11. The snow groomer according to claim 10, further characterized in that the further sensor system (13) for detecting the rotary position of the winch arm (4) has a rotary angle sensor (15) designed to detect a rotary angle (α) of the winch arm (4) relative to a longitudinal vehicle axis (FL).

12. The snow groomer according to any of claims 9 to 11, further characterized in that the sensor system (10) for detecting the cable tension of the winch cable (3) is arranged in the winch arm (4), in particular on a front end region (16) of the winch arm (4), and / or has a tensile force sensor (17) for detecting a tensile force (FZ) at the winch assembly (1).

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