Ground transport tool and method for operating same

Abstract

The invention relates to a ground vehicle and a method for operating the same. The ground transport comprises: a vehicle body (12) having a longitudinal direction and a width direction; a crane (20) extending in a substantially vertical direction from the vehicle body (12); an active orientation adjustment system (22) designed to cause a relative movement of the crane (20) with respect to the vehicle body (12); at least one support element (28) extending between a first coupling point (24) at the vehicle body (12) and a second coupling point (26) at the crane (20); and a support element adaptation system (30) which is designed to adapt the length of the support element (28) when the crane (20) is moved relative to the vehicle body (12) in such a way that a resulting relative displacement of the second coupling point (26) relative to the first coupling point (24) is compensated. The invention also relates to a method for operating such a ground vehicle.

Description

Technical Field

[0001] The invention relates to a ground vehicle comprising: a vehicle body having a longitudinal direction and a width direction; a crane extending from the vehicle body in a substantially vertical direction; an active orientation adjustment system designed to: cause relative movement of the crane relative to the vehicle body, for example to damp vibrations of the crane or to compensate for bending of the crane when moving a load in or out; and at least one support element extending between a first connection point at the vehicle body and a second connection point at the crane. The invention also relates to a method for operating such a ground vehicle. Background Art

[0002] It is known from the prior art and in particular from DE 10 2020 116 337 A1, for example, to provide active systems in ground vehicles for preventing crane vibrations and for compensating for crane deformations. Such systems usually include a detection unit which detects the state of the vehicle and / or its surroundings, wherein actuators are operated based on this detection, which cause a crane of the vehicle to move relative to the vehicle body, for example in order to reactively or actively suppress crane vibrations.

[0003] It is also known to provide a support device in a ground vehicle, which extends between a fixing point on the vehicle body of a corresponding vehicle and another fixing point on a lifting frame of such a vehicle, so that an improved support and force transmission between the lifting frame and the vehicle body can be provided. For example, reference should be made in this context to EP 3 263 510 A1, in which such a support device is provided in a ground vehicle, and a device for reducing vibrations is also associated with the support device.

[0004] However, it has been found in practice that although the combination of the two systems, namely the active position control system of the crane and the support, can in principle be advantageous and desirable in order to be able to combine the mentioned advantages of the two systems, the problem that arises at the same time is that in the case of a rigid design of such a support device, a rotation about the vertical axis is additionally possible in the case of a deflection by the active position control system. Therefore, this rigid connection in turn leads to additional uncontrolled movements of the load carried by the crane. Therefore, although a less rigid connection of the crane via the corresponding support element can be advantageous from this point of view, this can result in a less efficient transmission of force or a connection of the crane to the vehicle body via two connection points.

[0005] It is therefore desirable to be able to implement a combination of an active position control system and at least one supporting element in a ground vehicle, wherein undesirable interactions between the two components mentioned are excluded and thus an active position control of the crane should be achieved while at the same time the crane is optimally supported on the vehicle body by the at least one supporting element. Summary of the invention

[0006] In order to achieve the above-mentioned objects and to eliminate the mentioned disadvantages of the prior art, it is proposed according to the invention that a corresponding ground vehicle of this type is additionally equipped with a support element adaptation system, which is designed to adapt the length of the support element when the lifting frame is moved relative to the vehicle body, so that a relative displacement of the second connection point relative to the first connection point is compensated. In this way, in the ground vehicle according to the invention, it is achieved that a dynamic length adaptation of the at least one support element is carried out, so that an optimal stability or an optimal force flux can be maintained at any time and in any state of the lifting frame. In other words, the movement of the second connection point provided at the lifting frame is supplemented by the fact that the slack length of the at least one support element towards the vehicle body is changed in a suitable manner.

[0007] At this point, it is first necessary to explain that the term "essentially vertically" aligned crane can be understood to mean that the vertical alignment of the crane is primarily present in its non-deflected static state, whereby optimal handling of the load etc. is achieved with the aid of a load receiving device associated with the crane that can be displaced in height. At the same time, however, the crane should be deflected in at least one degree of freedom relative to the vertical by means of an active position adjustment system, wherein the position adjustment system can be designed in particular to pivot the crane about an axis parallel to the longitudinal direction of the vehicle body.

[0008] It should also be pointed out that the active positioning control system of the vehicle according to the invention can include at least one sensor for detecting the state of the vehicle and / or its surroundings, at least one actuator for triggering a relative movement of the crane relative to the vehicle body, a control unit for processing the data provided by the at least one sensor and for actuating the at least one actuator and, if necessary, a prediction unit, which is for example integrated with the control unit and for this purpose is able to predict future foreseeable disturbances from the detected current spatial and movement state of the vehicle and the knowledge about its surroundings and to perform active actuation of the at least one actuator in order to prevent or at least reduce predicted or expected vibrations or other disturbances of the crane. Similarly, bending of the frame can be compensated by the means mentioned when moving in and out a load, provided that such bending is detected by suitable sensors.

[0009] Furthermore, in order to ensure a constant force flux relative to the at least one supporting element during all possible operating states of the ground vehicle according to the invention, the ground vehicle can first be adjusted in a suitable manner with respect to its neutral position before commissioning of the ground vehicle, so that in the non-deflected neutral position of the crane a desired behavior of the supporting element with respect to absorption and transmission of forces is achieved. Furthermore, in this way, deflections of the crane relative to the vehicle body are compensated in a suitable manner by the supporting element and the supporting element adaptation system, so that a force transmission or retention that is as constant as possible can be ensured in all states of the crane.

[0010] In principle, different embodiments of the support element and the support element adaptation system are conceivable in the underground vehicle according to the invention in order to be able to achieve desired properties or a predefined mode of operation.

[0011] In a first conceivable variant, at least one support element can include a rigid first section and a second support section of variable length relative to the first connection point, and the support element adaptation system includes a mechanical coupling between the lifting frame and the second section. The term "variable length" second section is to be understood here as such that the distance between the end of the first section adjacent to the second section and the first connection point is also achieved, for example, by a suitable pivoting of a lever, which can be understood as the second section of the support element, or by providing an eccentric disk. Thus, in general, the second section is a component by means of which a change in the length of the support element between two connection points can be brought about in a general manner. Another example of this is a so-called "support-integrated" second section, which can be designed as a variable length element arranged at any position along the length of the support element, for example by a telescopic section, a variable length actuator, etc., so that the length of the support element at this location away from its two connection points can be adapted.

[0012] With regard to the aforementioned variants of the mechanical coupling of the support element adapter system, a number of specific embodiments are also conceivable, for example, the mechanical coupling can be formed by means of a connecting rod, which causes a change in the length of the support element by means of a connection to the lifting frame via a pivotable element. Thus, such an embodiment can be formed by means of a simple and rigid connection between corresponding pivotable joints or, for example, also via a bent lever with a corresponding swivel joint.

[0013] Another embodiment of such a mechanical coupling of the support element adapter system can be implemented by means of a Bowden cable, which, when the lift is moved relative to the vehicle body, causes a change in the length of the support element by being coupled to the lift. In such an embodiment, the second variable-length section of the support element is designed such that a shortening and lengthening of the second section is achieved by force transmission by means of the Bowden cable, so that any movement of the lift relative to the vehicle body can be converted in a suitable manner into a lengthening or shortening of the support element.

[0014] Furthermore, it is also conceivable that the mechanical coupling of the support element adapter system is formed by means of a cardan shaft, a spindle drive, a chain drive or a belt drive, wherein when the lifting frame is moved relative to the vehicle body, a rotational movement of the corresponding drive is triggered by the coupling to the lifting frame, which causes the second section of the support element to pivot in order to change the length of the support element. In this case, depending on the specific design, the corresponding second section of the support element can be formed, for example, as an eccentric disk or as a joint or hinge with a suitable lever ratio in order to convert the rotational movement transmitted by the corresponding drive into a corresponding change in the length of the second section of the support element.

[0015] Furthermore, the mechanical coupling of the support element adapter system can also be designed by means of a toothed rack, by means of which a displacement of the lift relative to the vehicle body is converted into a change in the length of the second section of the support element. In this case, a parallel displacement of the second section of the support element can be achieved in comparison with a deflection of the lift relative to the vehicle body, wherein suitable lever ratios can be provided between the support element and the lift in order to achieve different angles of the support element relative to the vehicle body, for example.

[0016] As an alternative to the variant with a mechanical coupling, the support element adaptation system can also include a hydraulic coupling between the lifting frame and the support element, wherein the slave element is coupled to the lifting frame and the variable-length master element is coupled to the support element and a movement of the lifting frame relative to the vehicle body is converted into a change in the length of the support element. In this case, the corresponding master element can be designed, for example, directly as a master cylinder, which can function as a second variable-length section of the support element, but more complex designs can also be provided, in which, for example, a telescopic change in the length of the support element is provided and the corresponding master element then causes the drive of the corresponding extension and extension movement of the telescopic system.

[0017] A similar, for example direct or telescopic, change in length of the support element can also be achieved in that the support element adaptation system comprises an electronic coupling between the lift and the support element, wherein a detection unit is associated with the lift and a variable-length adjustment unit is associated with the support element, and a movement of the lift relative to the vehicle body is detected by a control unit of the support element adaptation system and a change in length of the adjustment unit is caused based thereon. In this case, the detection unit can also be directly integrated with the active position control system, so that a corresponding actuation of the adjustment unit can be carried out in a coordinated manner by means of at least one actuator that actuates the position control system. Correspondingly, the expected deflection of the lift can be evaluated by the actuation of the position control system and applied directly to the adjustment unit, so that a suitable coordination of the two systems can be achieved. In this context, the corresponding adjustment unit can be designed in a manner known per se as an electromechanical adjustment drive, for example as a linear drive or a rotary adjustment motor with a suitable transmission unit for converting into a linear movement, which corresponds to a change in length of the adjustment unit and can thus cause an adaptation of the length of the support element.

[0018] Although it is also conceivable in principle to provide only a single support element on the ground vehicle according to the invention, wherein the support element extends between the first and second connection points mentioned on the vehicle body and the lift, it can be advantageous for improving the force absorption relative to the width direction of the ground vehicle to provide a plurality of support elements, i.e., for example two support elements, whose respective second connection points are spaced apart from one another in the width direction of the ground vehicle. Obviously, the first connection points can also be spaced apart from one another in a similar manner in the width direction of the lift, wherein the specific positioning of the individual connection points depends on the overall geometry of the respective ground vehicle and can be oriented, for example, according to the width of the vehicle body and the lift.

[0019] Furthermore, the ground vehicle according to the invention can be designed in particular as a narrow-aisle forklift and a vertically displaceable driver's seat support can be associated with the lift, so that the corresponding vehicle can be designed as a so-called "man-up vehicle". It has been found that the operating efficiency and the comfort of the driver can be significantly impaired by the resulting lift vibrations, because when the load receiving means or the driver's seat support is extended far, the prevailing lever ratios cause a strong deflection and a significant acceleration thereof relative to the ground.

[0020] According to a second aspect, the invention also relates to a method for operating such a ground vehicle, comprising: detecting vibrations of the lift and / or bending of the lift by means of at least one sensor unit of the position control system and / or predicting vibrations of the lift by means of a prediction unit of the position control system; actuating at least one actuator of the position control system to suppress the detected and / or predicted vibrations or to compensate for the detected bending of the lift by causing a movement of the lift relative to the vehicle body; and adapting the length of at least one support element in such a way that a resulting relative displacement of a second connection point relative to a first connection point of the at least one support element is compensated. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other advantages and features of the present invention become apparent from the following description of a possible embodiment thereof if the possible embodiment is considered in conjunction with the attached drawings. The drawings show in detail:

[0022] Figure 1 shows a schematic side view of an embodiment of a ground vehicle according to the invention, which embodiment can be combined with different variants of the support element adaptation system shown in the subsequent figures;

[0023] Figure 2a to Figure 2g A specific embodiment of a support element adaptation system having a mechanical coupling is shown;

[0024] Figure 3a and Figure 3b An embodiment of a support element adaptation system with a mechanical coupling and support-integrated length variation is shown;

[0025] Figure 4 One embodiment of a support element adapter system having a hydraulic coupling is shown;

[0026] Figure 5 One embodiment of a support element adapter system having an electronic coupler is shown; and

[0027] Figure 6 Show Figure 2d Detailed view of a variant of the support element adaptation system in FIG. DETAILED DESCRIPTION

[0028] exist Figure 1 In the figure, a test bench for a ground vehicle according to the invention is first shown. Here, the ground vehicle is generally indicated by the reference numeral 10 and is designed as a narrow-aisle forklift. The ground vehicle comprises a vehicle body 12 with a pair of front wheels 14, which are arranged on corresponding longitudinal supports 16, and driven and steered rear wheels 18, by means of which the vehicle 10 stands on the driving surface U.

[0029] Here, the rotation axes of the front wheels 14 and the rear wheels 18 extend in the width direction of the vehicle 10, respectively, and the straight-line running direction of the vehicle 10 is referred to as the longitudinal direction. Between the two axes of the front wheels 14 and the rear wheels 18 in the longitudinal direction of the vehicle 10, the lifting frame 20 extends in a substantially vertical direction. Figure 1 In the illustrated embodiment, the cab 20a is connected to the lifting frame 20 in a vertically displaceable manner.

[0030] The ground vehicle 10 shown here is mainly suitable for use in logistics devices due to its configuration with a lifting frame 20 arranged between the axes of the front wheels 14 and the rear wheels 18, in which narrow passages are provided only between the high racks, in which the goods are stored and can be picked up by an operator in the driver's cab 20a. It is understood that in alternative variants, the ground vehicle 10 can also be configured with a driver's cab fixedly arranged on the vehicle body 12 or can also be configured as an unmanned vehicle and can thus be operated autonomously or in a remotely controlled manner, wherein in this variant, the driver's cab is replaced by a corresponding structure. In addition, it is understood that the vehicle 10 can also include many other components that are common to such vehicles, such as a hydraulic system that can supply some of the actuators described below.

[0031] Furthermore, the vehicle 10 comprises an active position control system 22, which is only schematically shown, and is designed to cause a relative movement of the lift 20 relative to the vehicle body 12 in order to damp vibrations of the lift 20 and / or to compensate for bending of the lift 20 when a load is moved in or out. For this purpose, the position control system 22 can have components (not shown here), such as sensor units, actuator units, control units and prediction units, which evaluate the current state of the vehicle and / or its surroundings in a known manner and trigger a corresponding relative movement of the lift 20 relative to the vehicle body 12 in order to damp vibrations of the lift 12.

[0032] Furthermore, the vehicle comprises a support element 28 which extends in the form of a slack piece between the first connection point 24 at the vehicle body 12 and the second connection point 26 at the lifting frame 20 and serves to transmit forces between the lifting frame 20 and the vehicle body 12 and thus to support the lifting frame 20. It should be noted here that: Figure 1 Although only a single support element 28 is shown in FIG, variants of the vehicle 10 according to the invention are also conceivable which have two or more support elements 28 which can be designed and / or operated in the same manner.

[0033] In order to be able to compensate for changes in the distance between the connection points 24 and 26 in the event of a relative movement of the crane 20 relative to the vehicle body 12 triggered by the active position control system 22, the ground vehicle also includes Figure 1 The support element adaptation system 30 is shown only schematically in the figure and is designed to adapt the length of the support element 24 when the lifting frame 20 is moved relative to the vehicle body 12. Different embodiments of the support element adaptation system 30 are conceivable and are explained below with reference to the other figures.

[0034] In this document, respective embodiments of the vehicle according to the invention are shown, which are distinguished substantially by the respective design of their support element adapter system. Therefore, in order to avoid unnecessary repeated explanation of certain identical or equivalent components, these components are respectively provided with the same or similar reference numerals, each of which is increased by 100 and is referred to in the Figure 1 For example, the corresponding lifting frames are respectively provided with reference numerals 120, 220, 320, etc., while the vehicle bodies are provided with reference numerals 112, 212, 312, etc., and their corresponding descriptions are omitted. Figure 2a to Figure 2g , Figure 3a and Figure 3b They are shown in Figure 1 A variant of the support element adapter system with a mechanical coupling between the lift 20 and the support element 28 of the vehicle 10 in FIG. In all the figures described below, the corresponding movement of the individual components when the corresponding lift is moved is also indicated by means of arrows.

[0035] The first example of this is in Figure 2a 100 is shown in the figure, wherein the support element 128 includes a first section 128a and a second section 128b, and the support element 128 is only realized by the second section 128b, and the second section is configured as a rotatable element, which can compensate for the different distances between the first connection point 124 and the second connection point 126 of the support element 128 according to the angular position.

[0036] For this purpose, the support element adaptation system 100 comprises a connecting rod 130 which can convert a relative movement of the lifting frame 120 with respect to the vehicle body 112 into a corresponding pivoting movement of the second section 128 b of the support element 128, so that its length is adapted in a suitable manner to the deflection of the lifting frame 120. Thus, the correct length of the support element 128 is ensured in each deflection state of the lifting frame 120, wherein a corresponding design of the second section 128 b of the support element 128 and of the lever ratio of the connecting rod 130 can be coordinated with the specific prevailing geometric conditions of the vehicle 10 and can be achieved by Figure 1 The arrows shown in are used to track the specific movement of the connecting rod 130 and the second section 128 b of the support element 128.

[0037] In a similar way, in Figure 2b , shows an embodiment in which a toggle lever 230 is provided in the support element adapter system 200, which can also cause a pivoting of the second section 228b of the support element 228 and thus a change in its length. This variant is characterized by the fact that only a swivel joint and simple components are required, but the joint cannot be completely de-tensioned and the connecting rod used must be adjustable.

[0038] exist Figure 2c , a further variant is shown in which a collection of a Bowden cable 330 together with a corresponding second section 328 b of a support element 328 is used, the second section being variable in length in two directions due to the action of the Bowden cable 330 in accordance with a matching element 330 a associated with the lifting frame 320, that is to say, being extendable and shortened, so that all corresponding movements of the lifting frame 320 relative to the vehicle body 312 can be compensated.

[0039] exist Figure 2d Another variant of the support element adapter system 400 is shown in FIG. 1 , in which a cardan shaft 430 is provided, which is connected to the support element adapter system 400. Figure 2a and Figure 2b In a similar manner to the embodiment shown in , the second section 428b of the support element 428 is caused to twist, and the length of the second section is changed when the lifting frame 420 is deflected. It is shown here that in this embodiment, a high force transmission and an almost rigid connection are possible due to the provided cardan shaft 430, and a large flexibility in terms of its length is also achieved. However, this solution is relatively complex in terms of construction, since intermediate storage is required and the space requirement is increased. In addition, it is necessary to enter and exit the transmission in order to convert the initial linear movement of the lifting frame 420 relative to the vehicle body 412 into a rotational movement, which can then be converted again into a pivoting movement of the second section 428b of the support element 428.

[0040] exist Figure 2e Another variant is shown in FIG. 5 , in which a spindle drive 530 is used in the support element adaptation system 500 . Figure 2d In contrast to the embodiment with the cardan shaft 430, a completely rigid connection can be used and the corresponding spindle drive can be designed to be self-locking. Although high force transmission is also possible in this embodiment, at the same time, a precise support of the rotation axis of the spindle drive 530 is required, and increased manufacturing costs can be expected in this variant.

[0041] Figure 2fAn embodiment with a chain or belt drive is now shown, in which the support element adaptation system 600 is mechanically coupled by coupling the lifting frame 620 to a rotating disk of the chain or belt drive 630, and the second section 628b of the support element 628 is configured as an eccentric wheel, which produces a change in the length of the support element 628 when the rotation is triggered by the chain or belt drive 630.

[0042] exist Figure 2b , a further variant with a mechanical coupling is shown as a support element adapter system 700 with a rack unit 730, which can trigger a movement of the lifting frame 720 relative to the vehicle body 712 directly into a parallel movement of the second section 728b of the support element 728 relative to a corresponding displacement element at the lifting frame 720. This variant also enables an almost rigid connection and the possibility of high force transmission, but requires precise support of the corresponding shaft.

[0043] Figure 3a and Figure 3b Two variants 800 and 900 of the support element adapter system are now shown, in which the length variability of the support elements 828 and 928 is implemented in a "support-integrated" manner, i.e., the variable-length second section 828b or 928b of the support elements 828 and 928 is not arranged directly in the region of the first connection point 824, 924, but in a first section extending away from it relative to the length of the support element 828 or 928. In both variants, the respective first section 828a or 928a is therefore respectively designed in two parts and extends on both sides of the respective second section 828b or 928b.

[0044] In this case, in variant 800, a mechanical coupling 830 is provided, which first converts the movement of the lifting frame 820 into a rotational movement of the shaft, which in the region of the support element 828 converts the rotational movement into a linear movement again, which in the region of the second section 828b enables the extension and retraction of the support element 828. In contrast, in variant 900, a mechanical coupling 930 is used, which converts the movement of the lifting frame 930 relative to the vehicle body 912 into a telescopic movement of the support element 928 in a guided manner via a lever transmission through the forward and backward movement of the shaft.

[0045] In contrast to the previously discussed variants with mechanical couplings, Figure 4Now a variant of the support element adaptation system 1000 with a hydraulic coupling is shown, in which a hydraulic slave cylinder 1030 is first associated with the lifting frame 1020, while a master cylinder 1032, which functions as a second variable-length section 1028b, is associated with the support element 1028. In this case, a geometric relationship can be established by a suitable design of the two cylinders 1030 and 1032, which leads to a corresponding extension or shortening of the support element 1028 when the lifting frame 1020 is deflected relative to the vehicle body 1012. In particular, the slave cylinder 1030 hydraulically transmits a movement of the lifting frame 1020 in the same direction to the master cylinder 1032, and the corresponding hydraulic volumes of the two cylinders 1030 and 1032 can be adapted to the inclination of the support element 1028 relative to the vehicle body 1012.

[0046] exist Figure 5 1 shows an electronic support element adaptation system 1100 in a similar manner, in which an electronic coupling is provided between a lifting frame 1120 and a support element 1128, wherein a detection unit 1130 is associated with the lifting frame 1120 and a variable-length adjustment unit 1132 is associated with the support element 1128, and a movement of the lifting frame 1120 relative to the vehicle body 1112 is detected by a control unit 1134 of the support element adaptation system 1100 and, on this basis, a change in the length of the adjustment unit 1132 is caused. In this case, the adjustment unit 1132 can directly function as a variable-length second section 1128b of the support element 1128 or, for example, drive a telescopic section of the support element 1128 to move out and in. In addition, it should be pointed out that the detection unit 1130 or its control unit 1134 can also be directly integrated with a control unit of the orientation control system 1122, which is not further shown, and the control unit 1132 can be controlled in a collaborative manner based on detected data about the state of the vehicle 10 or its surroundings and the control of at least one actuator of the orientation control system 1122.

[0047] at last, Figure 6 Now show Figure 2d Detailed view of a variant travel in FIG. 4 , in which it becomes clear that the cardan shaft 430 acts on an eccentric 432, which in turn carries the first section 428a of the support element 428 and is correspondingly displaced by the rotation of the eccentric into a position corresponding to a different length of the corresponding support element 428, in order to compensate for the movement of the lifting frame 420, which firstly triggers the rotation of the cardan shaft 430. Thus, in this variant, the eccentric 432 corresponds exactly to the second variable-length section 428b of the support element 428.

Claims

1. A ground transportation tool (10), comprising: - a vehicle body (12) having a longitudinal direction and a width direction; - a lifting frame (20) extending from the vehicle body (12) in a substantially vertical direction; - an active position adjustment system (22), the position adjustment system being designed to cause a relative movement of the lifting frame (20) relative to the vehicle body (12); - at least one support element (28) extending between a first connection point (24) at the vehicle body (12) and a second connection point (26) at the lifting frame (20); and - a support element adaptation system (30) designed to adapt the length of the support element (28) when the lifting frame (20) is moved relative to the vehicle body (12) so as to compensate for the resulting relative displacement of the second connection point (26) relative to the first connection point (24).

2. The ground transportation vehicle (10) according to claim 1, The orientation adjustment system (22) is designed to enable the lifting frame (20) to pivot around an axis parallel to the longitudinal direction of the vehicle body (12).

3. A ground transportation vehicle (10) according to any one of claims 1 and 2, wherein the at least one support element (128, 828, 928) has a rigid first section (128a, 828a, 928a) and a second section (128b, 828b, 928b) of variable length relative to the first connection point (124, 824, 924), and The support element adapter system (100, 800, 900) includes a mechanical coupling between the lifting frame (120, 820, 920) and the second section (128b, 828b, 928b).

4. The ground transportation vehicle (10) according to claim 3, The mechanical coupling of the support element adaptation system (100, 200) is formed by means of a connecting rod (130, 230), which causes the second section (128b, 228b) of the support element (128, 228) to pivot to change the length of the support element (128, 228) by being connected to the lifting frame (120, 220) via a pivotable element.

5. The ground transportation vehicle (10) according to claim 3, The mechanical coupling of the support element adapter system (300) is formed by means of a Bowden cable (330), which, by being connected to the lifting frame (320), causes a change in the length of the support element (328) when the lifting frame (320) moves relative to the vehicle body (312).

6. The ground transportation vehicle (10) according to claim 3, The mechanical coupling of the support element adaptation system (400; 500; 600) is constructed by means of a universal joint (430), a spindle drive (530), a chain drive or a belt drive (630), wherein by being connected to the lifting frame (420; 520; 620), a corresponding drive (430; 530; 630) is triggered to rotate when the lifting frame (420; 520; 620) moves relative to the vehicle body (412; 512; 612), and the rotational movement causes the second section (428b; 528b; 628b) of the support element (428; 528; 628) to pivot to change the length of the support element (428; 528; 628).

7. The ground transportation vehicle (10) according to claim 3, The mechanical coupling of the support element adaptation system (700) is formed by means of a rack, by means of which a movement of the lifting frame (720) relative to the vehicle body (712) is converted into a change in the length of the second section (728b) of the support element (728).

8. A ground transportation vehicle (10) according to any one of claims 1 and 2, wherein the support element adaptation system (1000) comprises a hydraulic coupling between the lifting frame (1020) and the support element (1028), A slave element (1030) is associated with the lifting frame (1020), and a variable-length master element (1032) is associated with the support element (1028), and the movement of the lifting frame (1020) relative to the vehicle body (1012) is converted into a change in the length of the support element (1028).

9. A ground transportation vehicle (10) according to any one of claims 1 and 2, wherein the support element adaptation system comprises an electronic coupling (1130) between the lifting frame (1120) and the support element (1128), A detection unit (1130) is associated with the lifting frame (1020), and a variable-length adjustment unit (1132) is associated with the support element (1028), and a control unit (1134) of the support element adaptation system detects the movement of the lifting frame (1120) relative to the vehicle body (1112) and causes a change in the length of the adjustment unit (1132) based on the movement.

10. The ground vehicle (10) according to any of the preceding claims, comprising a plurality of support elements (28), the respective second connection points (26) of the support elements being preferably spaced apart from one another in the width direction of the ground vehicle (10).

11. A ground vehicle (10) according to any one of the preceding claims, The ground transport vehicle (10) is designed as a narrow-aisle forklift, and a driver's seat support (20a) that can be displaced in the vertical direction is associated with the lifting frame (20).

12. A method for operating a ground vehicle (10) according to any one of the preceding claims, comprising: - detecting vibrations of the crane (20) and / or bending of the crane (20) by means of at least one sensor unit of the position control system (22), and / or predicting vibrations of the crane (20) by means of a prediction unit of the position control system (22); - operating at least one actuator of the position adjustment system (22) to suppress detected and / or predicted vibrations or to compensate for detected bending of the crane (20) by causing a movement of the crane (20) relative to the vehicle body (12); and - The length of the at least one support element (28) is adapted in such a way that a resulting relative displacement of the second connection point (26) with respect to the first connection point (24) of the at least one support element (28) is compensated.

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