Adjustment device for vehicle seats

Description

[0001] The invention relates to an adjustment device for vehicles, in particular electric wheelchairs or rehabilitation vehicles, reclining systems and nursing beds, comprising at least one mounting plate and a support plate with a lifting device, which includes at least three or four scissor fittings arranged on the longitudinal side edge or in each corner area of ​​the mounting or support plate and adjustable in height via a drive means, wherein each scissor fitting is designed as a double scissor and has a first lower scissor element and a second upper scissor element, which are connected at one end via a common axis of rotation and the lower scissor element is connected at the other end to the mounting plate and the upper scissor element at the other end to the support plate via fastening means.

[0002] Vehicles of various designs are used for passenger transport, construction, and agriculture. In addition, there are electric wheelchairs and rehabilitation vehicles, some of which are designed to carry significant loads. For example, construction vehicles or agricultural vehicles such as tractors used in hilly terrain are equipped with seats that can be adjusted to a horizontal position using pneumatic cylinders. This feature facilitates work.

[0003] For electric wheelchairs or other vehicles designed to transport people with disabilities, a special seat adjustment may be necessary in individual cases, even on level ground. This might be due to physical anomalies or medical conditions that require the seat to be tilted or set at a specific angle to relieve pressure or perform certain tasks. Typical conditions with a significant risk of pressure ulcers include spinal cord injuries such as tetraplegia, ALS (amyotrophic lateral sclerosis), MS (multiple sclerosis), myopathies, neurological disorders, and traumatic brain injuries. An adjustable seat mechanism is intended to provide at least partial relief for these individuals. In some of these cases, the spontaneous movements necessary for pressure relief are impaired.The highly dynamic process of sitting is simulated by the movement of the adjustment mechanism. This protects users from pain and the resulting damage caused by static sitting.

[0004] An adjustment mechanism intended for an electric wheelchair must meet certain criteria. Firstly, the overall height must not exceed a certain limit, otherwise barrier-free access to the vehicle, for example, would be impossible. Secondly, the electric wheelchairs themselves must not exceed a certain height, as users typically require a table for work or personal activities, under which the wheelchair must be able to maneuver. Therefore, electric wheelchairs or rehabilitation vehicles must be able to assume different, adjustable positions while also fulfilling the aforementioned requirements.

[0005] US patent application 2002 / 0149168 A1 discloses an adjustment device for a wheelchair, consisting of a double scissor mechanism. The seat height can be adjusted using this double scissor mechanism, wherein a first scissor mechanism is directly coupled to a second scissor mechanism, and the free ends of each scissor mechanism are connected to other components of the wheelchair.

[0006] From EP 2 907 694 B1, an adjustment device for vehicle seats is known, which goes back to the same applicant. This application discloses the use of a mounting plate for the seat and a support plate with a lifting device, which comprises at least two scissor fittings arranged on the longitudinal side edge or in a corner area of ​​the mounting or support plate and adjustable in height via a drive mechanism. The scissor fittings are height-adjustable independently of each other. This adjustment device makes it possible to adjust the height of an existing seat surface, which is directly connected to the mounting plate, and also to raise it at the front and rear, so that the user of a wheelchair can reach a resting position or be made able to stand up more easily.Furthermore, the adjustment mechanism allows for lateral tilting of the seat surface, for example to compensate for typical symptoms of muscular dystrophy. However, the known adjustment device does not allow for diagonal tilting, which is also desirable in certain cases.

[0007] US patent 2,982,336 discloses a trolley with a seat and backrest, the height of which is adjustable via a double scissor mechanism. A hand crank is provided for adjustment, which, by means of a threaded spindle and a bushing with an internal thread, enables adjustment of the scissor mechanism.

[0008] US patent 5,613,255 discloses a mobile couch with height adjustment in which a double scissor fitting with the upper ends of the scissors can slide back and forth in a guide rail, this compensating movement serving to move the upper ends of the scissor fitting towards each other or away from each other.

[0009] US patent 3,522,922 discloses a treatment chair with a height adjustment mechanism in which the height adjustment is achieved by means of a double scissor fitting and the upper ends of the scissor fitting are each equipped with a sliding element which can slide back and forth on a guide rod.

[0010] The present invention is based on the objective of improving a known adjustment device with lifting device for vehicles in such a way that a diagonal tilting of the seat surface is possible.

[0011] To solve the problem, an adjustment device for vehicle seats with the features of the main claim is provided. Preferred embodiments are described in the dependent claims.

[0012] Lifting the rear scissor hinges of the mounting plate tilts the support plate forward. Lifting the front scissor hinges tilts the plate backward. It is also possible to lift either the left or right scissor hinges, tilting the seat to the right or left, respectively. If only height adjustment is desired, all scissor hinges are moved to approximately the same height. The aforementioned adjustments can also be made using three scissor hinges.

[0013] By equipping the adjustment mechanism with a fastening element in the form of a bracket connected to the support plate and a mounting unit axially movable relative to the bracket, to which the ends of the upper scissor element or the parallel scissor elements are rotatably attached, it is also possible to tilt the mechanism along the diagonal axis of the support plate. For this, it is necessary, for example, to leave the front right scissor fitting almost in the lowered position, while the rear left scissor fitting is raised almost completely, and the two remaining scissor fittings, rear right and front left, are only partially raised. Alternatively, tilting relative to the second diagonal axis can be achieved in a similar manner. The bracket and the mounting unit ensure that the mounting points of the upper scissor elements are aligned longitudinally.The vehicle's direction of travel is adjustable. This adjustment prevents the individual scissor hinges from becoming jammed in the event of diagonal tilting, thus ensuring the adjustment mechanism functions correctly without impairment. The longitudinal movement of the mounting unit relative to the console compensates for the different movements of the individual scissor hinges.

[0014] Medical considerations are crucial when determining whether a seat can be tilted or inclined. Typical conditions that necessitate this adjustment include muscular dystrophy, cerebral palsy (CP), and spina bifida. A 20° lateral tilt relieves pressure on the spine and ischial tuberosities in cases of scoliosis (an S-shaped, lateral curvature of the spine). The seat must be tilted to the side as needed until the shoulder girdle is horizontal. This allows for a natural head posture and improved perception. Users can usually determine the duration of the tilt themselves, thus providing targeted relief. A 40° backward tilt reduces pressure on the ischial tuberosities, which are prone to pressure ulcers (decubitus prophylaxis), by approximately 70 to 80% and is therefore also referred to as medical positioning. Eye contact is limited in this position.When used on a wheelchair, the additional forward tilt of the seat further balances the center of gravity, eliminating the risk of tipping backward caused by tilting the seat back. A 20° to 30° tilt provides a comfortable resting or relaxing position for the user. A 20° to 25° tilt combined with a 15° to 20° lateral tilt (diagonal tilt) results in up to 90% pressure relief (decubitus prophylaxis) for the right or left ischial tuberosity. Unrestricted eye contact with the immediate surroundings of the seat is maintained.

[0015] This can help patients with the typical clinical pictures of a significant risk of pressure ulcers due to spinal cord injuries, such as ALS, MS, myopathies, neurological diseases and stroke.

[0016] The integrated indication, for example, ensures that a 20 cm seat lift allows for easy access to higher objects and simple eye contact. A 20 cm seat lift combined with a simultaneous or subsequent forward tilt of up to 40° supports active standing for people with limited mobility or reduced muscle strength. When used on a wheelchair, the additional forward shift of the seat provides a clear standing area, unobstructed by the front wheelchair wheels.

[0017] With a 20° lateral tilt and variable stroke, it is possible to perform a simple, sideways sliding transfer, for example, onto toilets, beds, chairs, or changing tables. A sliding board can further assist the gliding function. Independent or lightly assisted transfers are essential for people who are reliant on an electric wheelchair due to significant mobility limitations, enabling them to live self-determined lives.

[0018] The extended adjustment mechanism allows for further positioning of the support plate, which is equivalent to adjusting the seat tilt – specifically, diagonal tilting. This allows for advantageous adjustment to the desired position a person with a disability needs, for example, to sit comfortably and perform their tasks without pain. Diagonal tilting simulates active sitting (micro-positioning). Tilting the support plate forward, for instance, facilitates getting on and off, while tilting it backward allows for a resting position. The adjustable height of the support plate / seat surface enables adaptation to existing table heights, allowing the user to position the front of the vehicle underneath a table.Driving on inclined surfaces is compensated for by a gyroscopic control, ensuring the person always remains in the desired seat angle. The particular advantage of this adjustment mechanism, thanks to the use of scissor hinges, is its extremely compact design, allowing for retrofitting to existing vehicles. With a total height of no more than 13 cm, it can be easily integrated into both existing and new vehicles.

[0019] Each scissor hinge consists of a double scissor mechanism, ensuring sufficient stability of the mounting plate and a high load-bearing capacity. The scissor elements of each hinge are offset within a single plane in such a way that they do not touch. This prevents jamming and allows for independent height adjustment.

[0020] Each scissor hinge consists of four pairs of scissor elements, each pair comprising a lower and an upper element. The lower and upper scissor elements, which have the same direction of inclination, are connected to a common pivot point via a pivot axis. This pivot axis ensures the articulation of the scissor elements, allowing them to pivot relative to the plane of the axis. The length of each scissor element determines the maximum stroke. Depending on the number of scissor elements used, their lengths must be matched or their spacing increased to prevent jamming. Alternatively, the scissor hinges can be offset laterally. With two scissor hinges positioned along the longitudinal edges of the mounting plate, sufficient space is available.However, if four scissor hinges are used, the length of the individual scissor elements must be dimensioned so that the hinges do not touch each other in their retracted position. Due to the paired arrangement of the scissor elements, which are rotationally fixed to each other via a shaft, both raising the mounting plate and adjusting its tilt are possible. When raising, the central axes of rotation of each scissor hinge remain in a horizontal position. As the hinges are raised, the axes of rotation move closer together, and as they are lowered, they move further apart.As far as an inclination is set, the raised axes of the actuated scissor fittings also remain in a horizontal position, while at the same time ensuring that the unactuated scissor fittings allow a pivoting movement through the upper scissor elements and that forward and backward tilting is possible.

[0021] For the assembly of the scissor fittings, it is provided that each scissor fitting has a first scissor element which is connected via a first pivot point to a console of the mounting plate or a box-shaped substructure and via a second central pivot point to a pivot axis, while the second scissor element is connected via a first pivot point to the support plate and the second central pivot point to the pivot axis of the first scissor element.

[0022] In this design, the free ends of each scissor fitting are connected to the mounting or support plate via a pivot point. The pivot axes arranged in the central area serve to support two lower and two upper scissor elements, so that they have a common pivot point and can perform synchronous movement via a threaded spindle.

[0023] The mounting plate is connected to the vehicle's undercarriage, while the support plate is designed for mounting the seat, with or without a backrest, forming the seat or, alternatively, a reclining surface. The scissor hinges are located between the mounting plate and the support plate.

[0024] In a further embodiment of the invention, it is provided that a bracket with fastening means is assigned to at least one longitudinal side of the upper scissor elements. This limits the longitudinal displacement of the bracket and fastening unit on one side of the adjustment device, while the opposing scissor elements are pivotally connected to the mounting plate, thus forming a fixed point that stabilizes the upper mounting plate but allows tilting due to the bracket and fastening unit.

[0025] The bracket is directly connected to the mounting plate, preferably by screws, and has a bore in which a guide rod of the mounting unit is received. The mounting unit itself consists of a base with two parallel legs, in which the bores are located to receive the guide rod, thus ensuring adjustability.

[0026] It should be noted that each scissor fitting consists of two parallel double scissor arms connected to the mounting unit. The scissor elements of the parallel scissor fittings are connected to each other via a pivot axis, while the adjacent scissor elements each have their own pivot point. Furthermore, the mounting unit may be pre-tensioned against the bracket by at least one spring resting on the guide rod. This spring assists in returning the mounting unit to the bracket.

[0027] Preferably, the fastening means with bracket and fastening unit are arranged on the longitudinal side of the adjustment device, which also allows for lateral displacement of the mounting plate.

[0028] The lateral displacement is already known from the applicant's earlier application, whereby in this case the upper pivot points are used with the axis of rotation to accommodate a sleeve which is pivotably and slidably mounted, the sleeve being connected to a bracket of the mounting plate via a radial extension. The bracket allows the extension to pivot so that the sleeve can be moved between the two pivot points, which essentially form a stop surface, depending on the position of the scissor fittings. The sleeve ensures that if the support plate tilts, for example, due to a lateral inclination to the left or right, no tension occurs within the scissor fittings and thus no blockage occurs.In this case, it is sufficient if the left- or right-hand scissor hinges on one long side are equipped with a movable sleeve, while the opposite hinges have a sleeve that is not slidably mounted on the axis of rotation. This ensures that any diagonal displacement relative to the scissor hinges can be compensated for during any lateral tilt, and that the total weight resting on the support plate is held securely and stably. Because the opposing scissor hinges do not have an axially movable sleeve along a long edge, unintentional lateral displacement of the support plate is prevented. The same applies to the resulting longitudinal movement, i.e.,in the direction of travel of the vehicle, whereby both the lateral and longitudinal displacement can be arranged on one side of the mounting plate, while the opposite side serves to fix the mounting plate. However, it is also entirely possible for the lateral and longitudinal displacement to be arranged on different longitudinal sides of the mounting plate.

[0029] The particular advantage of the present invention lies in the fact that, with the aid of at least two scissor hinges, preferably three or four scissor hinges, individual adjustment of the support surface for a seat is made possible. Each individual scissor hinge, with four lower and four upper scissor elements arranged in parallel pairs, exhibits extremely high stability, enabling even heavy loads, such as heavy individuals, to be moved vertically. Furthermore, four scissor hinges allow for individual adjustment of the seat tilt, specifically by tilting the seat forward or backward, or to the right or left.Furthermore, the additional mounting hardware, consisting of a bracket and a fastening unit, allows for adjustment in the direction of travel, which is necessary for diagonally tilting the mounting plate with the seat surface. The bracket and fastening unit ensure that no position of the mounting plate causes any tension on the individual scissor hinges, allowing them to be easily returned to their original position. The low-profile design, made possible by the scissor hinges, is particularly noteworthy, facilitating retrofitting in existing vehicles.Thanks to optimized control electronics and at least one, preferably several, position sensors, the seat position can be automatically detected and maintained in a predefined position, for example, when the vehicle is driven on a slope. Regardless of the terrain, the seat is maintained in the preselected position by adjusting the scissor mechanism. The scissor mechanism's actuators compensate for uneven terrain, especially on steep slopes, allowing the user to maintain an optimal seating position even during extended journeys. Furthermore, the seat position can be individually adjusted at any time to prevent uneven strain.

[0030] The invention will be explained again below with reference to the drawing figures.

[0031] It shows Fig. 1 in a perspective view of a vehicle with an adjustment device for an existing seat, Fig. 2 in a side view of the Figure 1 known vehicle, Fig. 3 in a side view the vehicle according to Figure 1 with a seat surface pushed forward, Fig. 4 in a perspective view the vehicle with a seat surface tilted backwards, Fig. 5 in a side view a vehicle with adjustment device and longitudinal displacement relative to the mounting plate, Fig. 6 in a side view the vehicle with adjustment device in a position in which the mounting plate has been raised to the maximum height and Fig. 7 in a side view the vehicle with adjustment device in a diagonal tilt.

[0032] Figure 1Figure 1 shows a perspective view of a vehicle 1 with an adjustment device 2, in this case, for example, a very robust electric wheelchair. The adjustment device 2 consists of a mounting plate 3 and a support plate 4, between which the lifting device 5 is arranged. Below the mounting plate 3 is the vehicle chassis 6, which in this case consists of a box-shaped housing 7 for accommodating the electronics and

[0033] Batteries are provided. Two large drive wheels 8 are attached to the housing 7 via a shaft with motors. In this case, the drive wheels 8 are not designed to be steerable, but indirect steering is achieved via the two independent motors, which can be driven at different speeds. Two further, smaller wheels 9 are mounted in a fork-shaped receptacle 10 by means of a pivot axle, with the two wheels 9 being connected to each other via a pendulum axle 11, and the pendulum axle 11 being screwed to the box-shaped housing 7. The vehicle 1 shown is thus steered by the drive wheels 8, with the necessary controls being integrated, for example, into the armrests 12.

[0034] The support plate 4 has a seat 13 and a backrest 14, the inclination of which can be adjusted via an adjustment unit 15. For this purpose, the backrest 14 is pivotally mounted via a pivot point 16. Armrests 12 are located on both sides of the seat 13. The robust design of the vehicle 1 already indicates that this type of vehicle is suitable for off-road use and also for heavier individuals. The lifting device 5 is located between the mounting plate 3 and the support plate 4. In the illustrated embodiment, this device consists of four scissor hinges 20 arranged in the corner areas. The construction of the scissor hinges 20 is shown in the following figures.

[0035] Figure 2 shows in a side view the from Figure 1The known vehicle 1 with the adjusting device 2, which is arranged between the mounting plate 3 and the support plate 4, shows that the drive wheels 8 are each driven by a motor connected to the housing 7. The other, rear wheels 9 are attached to a bracket 17 mounted on the housing 7 via a pendulum axle 11.

[0036] Figure 3 shows a side view of vehicle 1 according to Figure 1 , whereas in contrast to the Figure 2 The seat surface 13 with backrest 14 is additionally shifted forward in the direction of the front drive wheels 8. In this case, the seat position is adjusted, for example, by a linear actuator located below the mounting plate 3.

[0037] Figure 4 shows vehicle 1 in a perspective rear view according to Figure 1with the lower vehicle undercarriage 6 and the seat surface 13 with backrest 14, wherein the support plate 4 was raised relative to the mounting plate 3 in the front area by means of the lifting device 5. The lifting device 5 consists of a total of four scissor fittings 20, each consisting of four lower double-paired scissor elements 21 and four upper double-paired scissor elements 22. Double-paired in this case means two individual scissor elements 21 arranged side by side and one behind the other. The lower scissor elements 21 are connected to the mounting plate 3 at two lower pivot points 23 and to the second scissor elements 22 at two pivot points 24 at their other ends. The second scissor elements 22 are connected to the support plate 4 at two upper pivot points 25.The scissor elements 21 and 22 are connected at pivot point 24 via two pivot axes 27 and 28. Two lower pairs of scissor elements 21 are pivotable forward and connected to one pivot axis 27, while the other two pairs of scissor elements 21 are pivotable backward and connected to another pivot axis 28. The upper scissor elements 22 are also connected at pivot point 24 to the first pivot axis 27, allowing them to pivot forward. The other two pairs of scissor elements 22 are pivotable backward and connected to another pivot axis 28. Both pivot axes 27 and 28 are equipped with a spindle holder in the central area, into which a threaded spindle 26 is screwed.The threaded spindle 26 has opposing thread sections at its two ends, one left-handed and one right-handed, so that when the threaded spindle 26 is rotated, the two axes of rotation 27, 28 at the pivot point 24 are moved away from each other or towards each other. From the . Figure 4It can be seen here that the scissor hinges 20 in the front area of ​​the vehicle 1 are extended to such an extent that the seat surface 13 is raised at the front. The two pivot axes 27, 28 of the pivot point 24 are arranged close together, so that the lower scissor elements 21 are in an almost vertical position. The upper scissor elements 22 are tilted slightly backwards. In contrast, the rear scissor hinges 20 are shown in their lowest position, in which the two pivot axes 27, 28 of the scissor hinges 20 are widely spaced. Due to the seat tilt, which corresponds to the tilt of the support plate 4, the upper scissor elements 22 of the rear scissor hinges 20 are pivoted and adjust to the position of the support plate 4. This position is further illustrated in the Figure 5 to be taken again.

[0038] Figure 5Figure 1 shows a side view of a slightly modified vehicle 1' with an adjustment device 2. The vehicle 1' consists of a vehicle chassis 6 with a housing 7 and a console 18, which is designed to accommodate the steerable rear wheel 9. The front wheels 8, however, are not steerable. A mounting plate 3 is located on the vehicle chassis 6, which is designed for mounting the adjustment device 2. The adjustment device 2 consists of the lifting devices 5, i.e., the corresponding drive motors, which drive the spindles 26. The spindles 26 have two opposing threaded sections, so that the scissor fittings 20, which are designed as double scissor fittings, can be moved vertically. The scissor fittings 20 each consist of a lower scissor element 21 and an upper scissor element 22.The scissor fittings 20 are arranged in pairs, one behind the other. However, the length of the individual scissor elements 21, 22 ensures that adjustment is possible independently of the adjacent scissor fittings 20. The lower scissor elements 21 are connected to the mounting plate at a pivot point (not shown) and have a pivot axis 27, 28 at their other ends, which connects them to the upper scissor element 22. Both the lower scissor elements 21 and the upper scissor elements 22 are connected to each other in pairs and can be moved vertically by the drive motor via a threaded bracket that moves back and forth on the threaded spindle.

[0039] In the illustrated embodiment, the upper scissor elements 22 are connected to a mounting unit 30 at a pivot point 25, with each upper scissor element 20 being connected at a separate pivot point 25. The mounting unit 30 consists of a base 31, which has two parallel legs 32, 33 at its ends. A guide rod 34 is arranged between the legs 32, 33 and is fixed between them to prevent rotation. The guide rod 34 rests in a bore in a bracket 35, which is screwed or otherwise fastened to the mounting plate. The mounting unit 30 and the bracket 35 allow the mounting unit 30 to slide relative to the support plate 4, thus enabling compensatory movement when adjusting individual scissor fittings 20.This compensating movement prevents the scissor fittings 20 from jamming even in extreme positions, for example when the support plate 4 is tilted diagonally. Figure 5 The support plate 4 is shown in a slightly raised position, without any tilting.

[0040] Figure 6 shows in a side view the vehicle 1' with adjustment device 2, according to the design of the Figure 5 . In this case, the support plate 4 is shown in an elevated position, which makes it clear that the lifting device 5 is used to adjust the height of the scissor fittings 20, in this case a uniform height adjustment, so that the support plate 4 is raised parallel to the wheels 8, 9.

[0041] Figure 7The vehicle 1' with adjustment device 2 is shown in a position of the support plate 4, which exhibits a diagonal tilt. By means of the differently raised scissor hinges 20, the support plate 4 is tilted both forwards and to the side, resulting in a diagonal tilt. To prevent the scissor hinges 20 from locking against each other, a fastening device consisting of a fastening unit 30 and a bracket 35 is used. The bracket 35 is rigidly connected to the support plate 4 and accommodates the guide rod 34, which can move in the direction of travel, i.e., axially relative to the bracket 35. Thus, the fastening unit 30 is slidably mounted within a limited but sufficient range, preventing the scissor hinges 20 from jamming. The fastening unit 30 with the bracket 35 constitutes an additional component that allows for longitudinal movement.The mounting unit 30 with bracket 35 only needs to be provided on one longitudinal side of the mounting plate, while the opposite longitudinal side provides an axially fixed connection of the upper scissor elements 22 to the support plate 4. Only pivoting movement is required on the opposite longitudinal side. This ensures that the support plate 4 is fixed on one side and that unintentional longitudinal movement is not possible. The longitudinal movement provided by the mounting unit 30 and the bracket 35 is preferably provided on the longitudinal side of the support plate 4, where lateral displacement is also provided in accordance with the prior art. These two displacement options ensure movement of the scissor fittings 20 in every position, preventing them from jamming during diagonal tilting. Reference symbol list

[0042] 1, 1'Vehicle 2Adjustment device 3Mounting plate 4Support plate 5Lifting device 6Vehicle undercarriage 7Housing 8Drive wheel / Rear wheel 8Front wheel 9Rear wheel 10Receiver 11Pendulum axle 12Armrest 13Seat surface 14Backrest 15Adjustment device 16Pivot point 17Console 20Scissor fitting 21Scissor element 22Scissor element 23Pivot point 24Pivot point 25Pivot point 26Threaded spindle 27Axis of rotation 28Axis of rotation 30Fastening unit 31Base 32Leg 33Leg 34Guide rod 35Console

Claims

1. Adjustment device (2) for vehicles (1), in particular electric wheelchairs or rehabilitation vehicles, reclining systems and care beds, comprising at least one mounting plate (3) and a support plate (4) with a lifting mechanism (5), which comprises three or four scissor fittings (20), which are arranged on the longitudinal side edge or in a corner region of the mounting plate (3) or support plate (4) respectively and are height-adjustable by means of a drive mechanism, wherein each scissor fitting (20) is designed as a double scissor comprising a first lower scissor element (21) and a second, upper scissor element (22), which are connected at one end via a common axis of rotation, and the lower scissor element (21) is connected at the other end to the mounting plate (3) and the upper scissor element (22) is connected at the other end to the support plate (4) via fastening means, wherein at least one fastening means comprises a bracket (35) connected to the support plate (4) and a fastening unit (30) axially movable relative to the bracket (35), wherein the fastening unit (30) comprises a base (31) with two parallel legs (32, 33), in which there are bores for receiving a guide rod (34), wherein the two upper scissor elements (22) of a double scissor mechanism are pivotally mounted on the base (31) of the fastening unit (30), wherein the bracket (35) comprises a bore in which the guide rod (34) of the mounting unit (30) is received, which is mounted so as to be displaceable relative to the bracket (35) in the direction of travel of the vehicle (1) and to which the ends of the upper scissor elements (22) of at least one scissor fitting (20) are articulated, whereby the fastening means, consisting of the bracket (35) and the fastening unit (30), are arranged on the longitudinal side of the adjustment device (2), which also provides for transverse displacement of the upper scissor elements (22), or that the fastening means, consisting of the bracket (35) and a mounting unit (30) are arranged on the longitudinal side of the adjustment device (2) opposite the transverse displacement.

2. Adjustment device (2) according to claim 1, characterised in in that a bracket (35) with a fastening unit (30) is associated with the upper scissor elements (22) on at least one longitudinal side.

3. Adjustment device (2) according to one of claims 1 or 2, characterised in in that the scissor elements (21, 22) of a scissor fitting (20) are each arranged in an offset plane in such a way that they do not come into contact.

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