Lifting device for vehicles and vehicle with such a lifting device

Abstract

Lifting device (10) for vehicles (100, 100'), in particular wheelchair lift, with - a frame (12) that can be mounted on a vehicle (100, 100'), - a platform (14) guided on the frame (12), which can be moved back and forth between a retracted position (S1) and an extended position (S2), and - a lifting device (16) which is configured to move the platform (14) in its extended position (S2), relative to a height level (H) defined by the frame (12), between a raised position (P1) and a lowered position (P2), wherein the lifting device (16) has a lifting mechanism (20) which comprises at least one support arm (22, 22') for implementing a lifting movement on the platform (14), wherein the support arm (22, 22') is provided with at least one drive means (24, 24') for generating the lifting movement (S H) of the platform (14) between the raised and lowered positions (P1, P2), characterized in that the drive means (24, 24') has at least one multiple piston cylinder arrangement (42, 42').

Description

[0001] The invention relates to a lifting device for vehicles, in particular a wheelchair lift, comprising a frame that can be mounted on a vehicle, a platform guided on the frame which is movable back and forth between a retracted position and an extended position, and a lifting device which is configured to move the platform in its extended position, relative to a height level defined by the frame, between a raised position and a lowered position, wherein the lifting device has a lifting mechanism which includes at least one support arm for implementing a lifting movement on the platform, wherein at least one drive means for generating the lifting movement of the platform between the raised and the lowered position is assigned to the support arm.Furthermore, the invention relates to a vehicle, in particular a vehicle for passenger transport, with a vehicle chassis and a lifting device mounted on the vehicle chassis.

[0002] Lifting devices mounted on vehicles have long been known and serve to transport objects or people from inside the vehicle to the outside or from the outside into the vehicle. Such lifting devices are particularly useful when there is a difference in height between the vehicle interior and the point where the objects or people are to be placed using the lifting device, or when a gap or space needs to be bridged. Such lifting devices are especially suitable for vehicles used to transport wheelchair users. A lifting device of this type, developed by the applicant, is known, for example, from EP 2 436 555 B1.

[0003] The known lifting devices, also called cassette lifts, consist of a frame that can be mounted on a vehicle, a platform guided by the frame that can be moved back and forth between a retracted and an extended position, and a lifting mechanism by which the platform, in its extended position, is moved between a raised and a lowered position relative to a height level defined by the frame. The raised position is usually defined by the frame, which is fixed to the vehicle. The height difference to be overcome between the raised and lowered positions often varies depending on the height level at the point that the platform of the lifting device has to reach.The lifting device known from EP 2 436 555 B1 comprises a lifting mechanism with at least one support arm used to transfer the lifting movement of the platform, relative to the frame in the vertical direction. A drive element designed as a lifting cylinder interacts with the support arm to generate the lifting movement of the platform. Due to their compact design and integration into the vehicle floor, the lifting devices, which are to be mounted in the floor area of ​​the vehicle, already require a comparatively small installation space. With the advent of e-mobility, the space requirements of components to be installed on the vehicle are playing an increasingly important role, as these components compete for available installation space with the battery modules, which are often also mounted in the vehicle floor area.

[0004] Therefore, the invention was based on the objective of providing a lifting device for vehicles which, on the one hand, is further improved in terms of its compact design and thus has a further reduced space requirement, and by means of which, despite everything, a safe and effective transfer of an object or a person from the interior of the vehicle to the outside of the vehicle and in the opposite direction is possible.

[0005] The invention solves the present problem in a vehicle lift, in particular a wheelchair lift, with the features of claim 1. In particular, it is provided that the drive element comprises at least a multi-piston cylinder arrangement. By designing the drive element as a multi-piston cylinder arrangement, the invention pursues the approach of further reducing the dimensions of the drive element, which typically contributes significantly to the overall dimensions of the lift, especially its height, compared to known solutions.This allows the required installation space on a lift device designed according to the invention with such a multi-piston cylinder arrangement to be further reduced, thus making the lift device according to the invention significantly more compact, which further simplifies the integration of a lift device designed according to the invention into the vehicle floor of a vehicle even in confined spaces.

[0006] According to a preferred embodiment of the lifting device, the multi-piston cylinder arrangement comprises at least two parallel-connected, preferably hydraulically actuated pistons. By connecting or actuating at least two pistons in parallel, and thus preferably at least halving the piston area of ​​each piston, the cross-sectional dimension of the pistons in the multi-piston cylinder arrangement can be reduced by a factor of approximately √2 compared to the cross-sectional dimension of a single lifting cylinder with only one piston area. This achieves the significant reduction in the vertical dimension of the lifting device according to the invention, which has a decisive effect on the required installation space of the lifting device.Preferably, the at least two pistons of the multi-piston cylinder arrangement are hydraulically actuated, which ensures that, despite the even more compact design of the lifting device, at least equally large loads can still be moved safely, in this case lifted or lowered.

[0007] According to a preferred embodiment, the at least two pistons of the multi-piston cylinder arrangement are arranged parallel to each other or in series one behind the other. These two different arrangements of the pistons relative to each other—parallel to each other or in series one behind the other—allow for simplified structural and design adaptation of the lifting device to vehicle-specific specifications or requirements. If a short stroke is crucial for integrating the lifting device according to the invention into a vehicle floor, the pistons are preferably arranged parallel to each other. However, if the dimensions transverse to the longitudinal axis of the piston are more critical for space-saving integration of the lifting device according to the invention than its overall length and the stroke achieved by means of the multi-piston cylinder arrangement, arranging the at least two pistons in series one behind the other is advantageous.

[0008] A possible further development of the lifting device involves integrating at least two pistons into a common cylinder housing, or arranging each of the at least two pistons in a separate cylinder housing. Integrating the two pistons into a common cylinder housing simplifies both the mounting of a single cylinder housing to the lifting device and the fluid connection to corresponding fluid lines coupled to the cylinder housing. Furthermore, the control of the at least two pistons integrated into a common cylinder housing is also improved. Specifically, two pistons arranged in series but controlled in parallel are integrated into a common cylinder housing, with two hydraulically separated cylinder chambers formed within the cylinder housing.The pistons arranged in series are, however, directly mechanically coupled or connected to each other, for example, by means of a piston rod. The provision of two or more separate cylinder housings, each to accommodate a single piston, is preferably implemented in conjunction with a parallel arrangement of the number of pistons used to design the multi-piston cylinder assembly, whereby the cylinder housings are then each individually connected to corresponding fluid lines for the necessary fluid control.

[0009] According to a preferred embodiment, a carriage is further provided that accommodates the lifting device and allows the platform to be moved in a plane relative to the frame. By means of the carriage according to the invention, the platform can be moved back and forth between the retracted and extended positions on the frame relatively easily and without significant effort. The carriage preferably has several roller elements, which are preferably movably mounted in several rail elements connected to the frame, which is fixed to the vehicle floor. The carriage supporting the platform is designed to be movable in a plane approximately parallel to the vehicle floor, which is essentially horizontal during operation of a lifting device according to the invention. A drive mechanism is provided on the carriage, by means of which the carriage is moved in the plane of travel.

[0010] According to a preferred embodiment, the at least one support arm is rotatably connected to the platform at a first end and pivotably connected to the frame at a second end arranged opposite to the first end, preferably to the carriage movably mounted on the frame. During operation, the support arm, which preferably couples the platform to the frame via the carriage, enables a structurally reliable force transmission from the lifting device according to the invention, in particular from the platform, through the connected frame into the vehicle floor that receives the frame. The support arm itself has a correspondingly high section modulus to reliably transmit the forces acting upon it from the platform towards the frame. When only one support arm is used, it interacts with the platform via only one connection point.Preferably, to reinforce such a one-sided connection area, a holding structure connected to the platform is provided, via which a uniform force transmission from the platform to the single support arm is effected.

[0011] In order to implement the necessary relative movements between the platform and the at least one support arm, and between the support arm and the carriage on the lifting device that accommodates the support arm, a preferred embodiment states that the at least one support arm is pivotally connected to the carriage by means of a pivot bearing, preferably attached to it. This ensures the necessary freedom of movement between the components that transmit the force is achieved in a simple manner both when lowering the platform from the raised position to the lowered position and when raising the platform from the lowered position to the raised position, so that the platform can maintain its preferably horizontal orientation.

[0012] A preferred embodiment of the lifting device provides that the at least one support arm is adjustable in a pivot plane, wherein, in the mounted state of the lifting device on a vehicle, the pivot plane runs essentially perpendicular to one longitudinal side of the vehicle. With the aid of the pivot plane of the support arm, which preferably runs perpendicular to the longitudinal side of the vehicle, the platform coupled to it can be moved relatively easily and safely along its length from the raised to the lowered position and from the lowered to the raised position, without the risk of unintentional contact with the longitudinal side of the vehicle. A person, particularly one being transported in a wheelchair, can be moved relatively easily from street level to the height of the vehicle interior in the easily accessible side area of ​​the vehicle.

[0013] Preferably, the at least one pivot bearing has a pivot axis that runs parallel to the travel plane of the slide, with the pivot axis being oriented transversely to one of the slide's travel directions. The targeted alignment of the pivot bearing allows for controlled lifting movement along the longitudinal side of the vehicle between the raised and lowered positions.

[0014] Preferably, the lifting device has two support arms, the pivot planes of which are preferably parallel to each other, with each support arm being connected at its first end to a longitudinal side of the platform. By providing two support arms, preferably arranged approximately parallel to the longitudinal sides of the platform, which is designed to be movable in the vertical direction, a structurally simple connection of the lifting mechanism to the lifting device according to the invention is achieved. The support arms, which engage both longitudinal sides of the platform, ensure a uniformly distributed force transmission from the platform, via the support arms, into the frame, which then transmits the forces into the vehicle floor.By using two support arms on the lifting device, these can be made smaller compared to a design with only one support arm, which further contributes to the compact design of the lifting device according to the invention. Furthermore, each individual connection area between a support arm and the platform, through which the relative movement between the support arms and the platform is ensured, can have reduced strength and correspondingly adapted dimensions compared to a single-sided connection area. In a preferred embodiment, each of the support arms connecting the platform to the carriage is assigned a drive element for generating the lifting movement of the platform. Preferably, each drive element coupled to a respective support arm has a multi-piston cylinder arrangement according to the invention with at least two parallel, preferably hydraulically actuated pistons.

[0015] According to a preferred embodiment of the lift device, the support arm has a straight profile section with a longitudinal axis, wherein a pivot bearing defining the pivot axis for the support arm has a lateral offset from the longitudinal axis on the profile section. The provision of a particularly straight profile section results in a structurally simple design of the support arm as a connection between the carriage, which moves along the frame, and the platform coupled to it. Furthermore, the straight course of the support arm further improves the preferably reduced design in the vertical direction of the lift device.

[0016] Preferably, the pivot bearing connecting the support arm to the carriage has a lateral offset from the longitudinal axis, so that, due to the leverage effect, an improved torque acting on the support arm can be generated by the drive element acting on the support arm to convert the lifting movement on the platform. This lateral offset from the longitudinal axis on the support arm creates an eccentric pivot point on the carriage, forming an efficiently driven lifting mechanism.

[0017] A possible further development of the lifting device provides for the drive mechanism to interact with a force application point formed on at least one of the support arms, which is laterally offset from the longitudinal axis, in particular from the pivot bearing, on the support arm. This force application point, laterally offset from the longitudinal axis, also results in an increased force torque and thus an improved force effect of the drive mechanism on the support arm when performing the lifting movement on the platform or when moving the platform between its raised and lowered positions. The force application point for the drive mechanism, which in this case is also designed as a type of pivot bearing, is preferably located near a longitudinal side of the support arm that defines its height.

[0018] In a preferred embodiment, the point of force application and the pivot bearing are arranged on opposite sides of the longitudinal axis of the support arm. Preferably, the pivot bearing for the support arm and the point of force application, which is preferably designed as a rotary bearing, are spaced as far apart as possible by the arrangement according to the invention. Thus, the maximum possible leverage is achieved with the drive element acting at the point of force application, simplifying the raising and lowering of the platform. The point of force application and the pivot bearing are preferably spaced as far apart as possible transversely to the longitudinal axis of the support arm and are each located in the region of the longitudinal sides of the support arm facing away from each other. In one embodiment, the point of force application and the pivot bearing are arranged approximately equidistant from the first end of the support arm in the longitudinal direction.

[0019] A preferred embodiment of the lifting device provides that the multi-piston cylinder assembly is connected to the point of force application on the lifting mechanism via at least one connecting element, in particular a strut structure, which is preferably curved or inclined at an angle α to the central axis of a piston on the assembly. The connecting element, which movably couples the drive element to the lifting mechanism, provides a comparatively simple yet structurally stable coupling between the multi-piston cylinder assembly and, in particular, the support arm of the lifting mechanism. Furthermore, the connecting element, which is preferably designed as a type of strut structure, ensures the reliable transmission of the adjustment movement generated by the drive element to the support arm and the resulting lifting movement to the platform coupled to the support arm.The connecting element, in particular the strut structure rigidly connected to the cylinder housing, is curved in the direction of extension with respect to a central axis of the at least one piston guided in the cylinder housing, or the connecting element, which is essentially straight, is inclined at an angle α to the central axis of the piston. This allows the multi-piston cylinder assembly, preferably mounted symmetrically on the carriage in the vertical direction of the lift device, to be connected to the force application point located off-center on the support arm for the longest possible lever arm, without requiring additional installation space in the vertical direction. The connecting element formed on the cylinder housing of the assembly has, in particular, two parallel connecting struts, each with a connection point for coupling to the support arm.Preferably, the connecting struts are connected to each other via at least one stiffening strut running transversely to them, which is further attached to the end face of the cylinder housing.

[0020] According to a preferred embodiment, the multiple piston-cylinder assembly is movably mounted on the slide and coupled to the lifting mechanism. The movable coupling of the drive element to the slide, and preferably also to the lifting mechanism via the connecting element, ensures the smooth execution of the platform's lifting movement between its raised and lowered positions. In particular, the pivoting support arm mounted on the slide causes a relative movement of the drive element, specifically a pivoting movement of the drive element relative to the slide, when the platform is lowered from the raised to the lowered position. This relative movement is made possible by the movable coupling of the drive element to the slide, which in one embodiment is achieved by incorporating a rotary bearing at the piston ends of the multiple piston-cylinder assembly.

[0021] In another aspect, the present invention relates to a vehicle, in particular a vehicle for passenger transport, comprising a vehicle chassis and a lifting device mounted on the vehicle chassis.

[0022] The invention solves the problem underlying the lifting device in a vehicle by designing the lifting device according to one of the preferred embodiments described above. By means of the inventive design of the drive element as a multiple-piston-cylinder arrangement, wherein the multiple-piston-cylinder arrangement preferably comprises at least two parallel-connected, preferably hydraulically actuated pistons, the overall dimensions of the lifting device, in particular the vertical dimensions, can be reduced such that the lifting device, designed as a cassette lift, has a reduced installation space and the space required for the lifting device in a vehicle floor is reduced to a minimum.Specifically, the drive mechanism that implements the movement, especially the lifting movement of the platform, by means of which a comparatively high force must be applied and which is often decisive for the dimension in the vertical direction, can, in relation to its cross-sectional dimension, be reduced by a factor of about √2 compared to a conventionally designed drive mechanism.

[0023] The invention utilizes the same advantages in the second aspect as the lifting device according to the first aspect. Preferred embodiments or further developments of the first aspect, such as the design of the piston, the design and connection of the support arm, or the connection of the drive element to the carriage and the support arm, are also preferred embodiments or further developments of the vehicle according to the second aspect. Therefore, to avoid repetition, reference is made to the above descriptions of the lifting device.

[0024] Another aspect of the present invention relates to a lifting device for vehicles, in particular a wheelchair lift, according to the preamble of claim 1.

[0025] The invention solves the problem underlying the lifting device according to the first aspect in a lifting device according to the third aspect by providing the drive element with at least one multi-spindle drive arrangement. Using the multi-spindle drive arrangement, the overall vertical dimension of the lifting device can be significantly reduced in a nearly identical manner compared to lifting devices known in the prior art. This simplifies the assembly or integration of such a lifting device designed according to the invention into a vehicle floor, for example, of an electric vehicle, which typically has one or more battery modules in the area of ​​the vehicle floor.

[0026] In yet another aspect, the invention relates to the use of a multiple piston-cylinder arrangement, in particular a double piston cylinder, or a multiple spindle drive arrangement for moving a platform between a raised and a lowered position on a vehicle lift device according to one of the preferred embodiments described above. The use of a multiple piston-cylinder arrangement or a multiple spindle drive arrangement designed according to the invention allows for a more compact overall design of the lift device. Furthermore, the significantly reduced overall height dimension of the lift device reduces the space required within a vehicle floor, thus facilitating the simplified integration of such a lift device into the floor of a vehicle, particularly a passenger vehicle.

[0027] The use according to the invention also takes advantage of the same benefits as all of the aforementioned aspects of the present invention, wherein the preferred embodiments or further developments described for the drive means, the lifting mechanism, in particular the support arms and for connecting the drive means to the lifting mechanism according to the aforementioned aspects are also preferred embodiments and further developments of at least the use according to the invention, which is why, to avoid repetition, reference is also made here to the above statements on the aforementioned aspects of the invention.

[0028] Further advantages and examples of implementation are described in more detail with reference to the accompanying figures. These show: Fig. 1: a perspective view of a vehicle according to the invention with an embodiment of a lifting device according to the invention; Fig. 2: a top view of the lift device according to Fig. 1; Fig. 3: a sectional view of the lifting device according to the invention with its platform located at least partially in the lowered position; Fig. 4: a perspective partial view of the lifting device according to the invention; Fig. 5 and Fig. 6: Perspective views of a drive means according to the invention used on the lift device, and Fig. 7: a perspective view of an alternative embodiment of a drive means according to the invention in partial section.

[0029] Fig. Figure 1 shows a vehicle 100, which has a schematically represented vehicle chassis 102 and several wheels 104 that support the vehicle chassis 102. A lifting device 10 is arranged on the vehicle 100, which is in particular a vehicle 100' for transporting persons, especially on its vehicle chassis 102, by means of which objects or persons can be transported from the interior of the vehicle to the outside or from the outside into the interior of the vehicle.

[0030] The lifting device 10 comprises a frame 12 attached to the vehicle 100, a platform 14 movably guided on the frame 12, and a lifting device 16. The platform 14 is moved back and forth on the frame between a retracted position S1 and an extended position S2 by means of a drive unit 18. The lifting device 16 is configured to move the platform 14 in the extended position S2, relative to a height level H defined by the frame 12, between a raised position P1 and a lowered position P2.

[0031] As from Fig. 1 in conjunction with Fig. As can be seen in Figure 2, the lifting device 16 has a lifting mechanism 20 with at least one support arm 22, 22'. The lifting mechanism 20, with its at least one, or in the embodiment shown, two support arms 22, 22', serves to implement the lifting movement on the platform 14, wherein the lifting device 16 further comprises at least one drive means 24 coupled to the support arms for generating the lifting movement S H which has platform 14.

[0032] at least one support arm 22 or the support arms 22, 22' are in a pivot plane E S adjustable, which, in the mounted state of the lifting device 10 on the vehicle 100, runs essentially perpendicular to a longitudinal side 106 of the vehicle 100. As further described, Fig. 1 and Fig. 2. The pivot planes E run S The support arms 22, 22' preferably parallel to each other.

[0033] Each support arm 22, 22' is rotatably coupled to the platform 14 at a first end 26 and at least pivotably coupled to the frame 12, in particular to the carriage 30 which is movable along the frame 12, at a second end 28 arranged opposite to the first end 26.

[0034] The carriage 30 is actively moved by means of the traverse drive 18 within the frame 12 in the direction of travel R. F moved. The sled 30 shows how Fig. 2 and Fig. Figure 4 illustrates several roller elements 32, 32' by means of which the carriage 30 moves in guide rails 34, 34' of the frame 12 ( Fig. 1) is recorded while moving.

[0035] Furthermore, the carriage 30 is designed to accommodate the lifting device 16 with the lifting mechanism 20 and the platform 14 which can be raised and lowered by means of the lifting mechanism 20, and to move it back and forth between the retracted and extended positions S1, S2.

[0036] The support arms 22, 22' are each connected at their first ends 26 to a longitudinal side 36, 36' of the platform 14, in particular in a pivoting manner. As the Fig. As illustrated in Figures 1 to 4, the support arms 22, 22' are designed as a straight-extending profile section 38 with a longitudinal axis L. A pivot bearing 40, by means of which the second end 28 of the support arms 22, 22' is pivotably connected to the slide 30, defines a pivot axis X on each support arm 22, 22', which has a lateral offset A1 to the longitudinal axis L. Each support arm 22, 22' thus has a pivot bearing 40 that defines a pivot point 40' formed off-center to the longitudinal axis L on the profile section 38.

[0037] The pivot axis X defined by the pivot bearing 40 runs in particular parallel to the axis defined by the direction of travel R. F defined travel plane E Fof the slide 30. In addition, in the embodiment shown here, the pivot axis X is transverse to the direction of travel R. F of the sled 30 aligned.

[0038] How Fig. As shown in Figures 4 to 6, the drive means 24 used to generate the lifting motion on the platform 14 comprises at least one multi-piston cylinder arrangement 42. The multi-piston cylinder arrangement 42 has two parallel-connected, preferably hydraulically actuated pistons 44, 44'. In an embodiment not shown in detail, the multi-piston cylinder arrangement 42 can also have more than two, in particular three or even four pistons 44, 44'.

[0039] In the embodiment shown here, the two pistons 44, 44' of the multiple-piston cylinder assembly 42 are arranged parallel to one another. The drive element 24, designed as a multiple-piston cylinder assembly 42, interacts with a force application point 46, which is located in the region of the second end 28 on at least one of the support arms 22, 22', or, in the embodiment shown here, on both support arms 22, 22'. The force application point 46 has a lateral offset A2 both relative to the pivot bearing 40 and to the longitudinal axis L on the support arm 22, 22'.

[0040] In the embodiment shown here, the force application point 46 and the pivot bearing 40 and the pivot point 40' defined thereby are arranged on opposite sides of the longitudinal axis L on the support arms 22, 22'. The pivot bearing 40 and the force application point 46 are arranged on opposite longitudinal sides 48, 48' of the profile section, which in particular has a rectangular cross-section, thus defining the longest possible lever arm between the force application point 46 and the pivot point 40'.

[0041] The multiple piston cylinder arrangement 42 is as shown in the diagram. Fig. 4 and Fig. As can be seen in Figure 5, the connecting element 50 is connected via at least one connecting element 50, in particular a strut structure 50', to the force application point 46 on the lifting mechanism 20, in particular to the second end 28 on the support arms 22, 22'. The connecting element 50 has such a stable or rigid structure that a drive force generated by the drive means 24 is reliably transmitted to the lifting mechanism 20 of the lifting device 16 to generate the lifting movement on the platform 14.

[0042] The pistons 44, 44' each have a central axis M that runs parallel to each other. The connecting element 50 is curved relative to a central axis M of the piston on the arrangement 42 or is inclined at an angle α to the central axis M of the pistons 44, 44'.

[0043] How the Fig. As can be seen from Figures 4 to 6, the free ends 52 of the pistons 44, 44', together with a bearing element 54 formed on the slide 30, define a rotary bearing 56 by means of which the multiple piston-cylinder assembly 42 is movably arranged on the slide 30. When the lifting movement is implemented on the platform 14, a relative movement of the drive element 24, designed as a multiple piston-cylinder assembly 42, relative to the slide 30 and the lifting mechanism 20, which is also movably coupled to the drive element 24, is thus possible.

[0044] The two pistons 44, 44' of the multi-piston cylinder arrangement 42 are integrated in the embodiment shown here within a common cylinder housing 58 with several cylinder chambers 60, 60'. A fluid connection 62 is provided on the cylinder housing 58 to actuate the pistons 44, 44', which are movably mounted within it. Pressure increases and decreases in the cylinder chambers 60, 60' are effected through this connection. The cylinder chambers 60, 60' are fluid-conductingly connected to each other via a connecting line 64.

[0045] In an embodiment not shown in detail, instead of a single cylinder housing 58, several separate cylinder housings can be provided, each containing a single piston movably mounted in it. The correspondingly separately designed cylinder housings are then each supplied with the working fluid, which is designed in particular as a hydraulic fluid, for driving the pistons via their own fluid connections.

[0046] Fig. Figure 7 shows an alternative embodiment of a drive means 24' according to the invention as a multiple piston cylinder arrangement 42', which has several pistons 66, 66' connected in parallel from a fluid-conducting point of view, but instead of being arranged side by side in a row one behind the other.

[0047] The multi-piston cylinder arrangement 42' has a common cylinder housing 68 for each of the pistons 66, 66' arranged in series. The cylinder housing 68 comprises cylinder chambers 70, 70', which are arranged one behind the other in the longitudinal direction of the cylinder housing and each has its own fluid connection 72. The pistons 66, 66', which are movable in the cylinder chambers 70, 70', are fluidly separated from each other, with the piston 66 being force-transmittingly coupled to the piston 66' arranged downstream by means of its piston rod 74, 74', so that the pistons 66, 66' arranged in series together define a single piston 76.

[0048] With the parallel arrangement of pistons 44, 44' and 66, 66', as well as the arrangement arranged in series, the same forces can be transmitted despite the pistons having nearly identical cross-sectional areas. The pistons 44, 44' arranged side by side require more installation space in the width direction, whereas the pistons 66, 66' arranged in series in arrangement 42' require more installation space in the longitudinal direction of the drive element.

[0049] In an embodiment not shown in detail, a drive means is used to implement the lifting movement on platform 14, which has at least a multi-spindle drive arrangement.

[0050] Identical or similar components are marked with the same reference symbols. Reference symbol list 10 Lifting device 12 frame 14 Platform 16 Lifting device 18 Traction drive 20 Lifting mechanism 22, 22' support arm 24, 24' propulsion system 26 first end 28 second end 30 sleds 32, 32' roller elements 34, 34' guide rail 36, 36' long side 38 Profile part 40 swivel bearings 40' pivot point 42, 42' Multi-piston cylinder arrangement 44, 44' piston 46 Force application point 48, 48' long side 50 connecting element 50' strut structure 52 free ending 54 Bearing part 56 swivel bearings 58 cylinder housings 60, 60' cylinder chamber 62 Fluid connection 64 Connecting line 66, 66' piston 68 cylinder housings 70, 70' cylinder chamber 72 Fluid connection 74, 74' piston rods 76 individual pistons 100, 100' vehicle 102 vehicle chassis 104 wheels 106 Long side α angle A1, A2 lateral offset E F Travel plane E S pivot plane H Altitude L Longitudinal axis M center axis P1 raised position P2 lowered position R F Direction of travel S1 retracted position S2 extended position S H Lifting movement X swivel axis QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 436 555 B1 [0002, 0003]

Claims

[1] Lifting device (10) for vehicles (100, 100'), in particular wheelchair lift, with - a frame (12) that can be mounted on a vehicle (100, 100'), - a platform (14) guided on the frame (12), which can be moved back and forth between a retracted position (S1) and an extended position (S2), and - a lifting device (16) which is configured to move the platform (14) in its extended position (S2), relative to a height level (H) defined by the frame (12), between a raised position (P1) and a lowered position (P2), wherein the lifting device (16) has a lifting mechanism (20) which comprises at least one support arm (22, 22') for implementing a lifting movement on the platform (14), wherein the support arm (22, 22') is provided with at least one drive means (24, 24') for generating the lifting movement (S H) of the platform (14) between the raised and lowered positions (P1, P2), characterized by , that the propulsion means (24, 24') has at least a multi-piston cylinder arrangement (42, 42'). [2] Lifting device (10) according to claim 1, characterized by , that the multiple piston cylinder arrangement (42, 42') comprises at least two parallel connected, preferably hydraulically actuated pistons (44, 44', 66, 66'). [3] Lifting device (10) according to claim 2, characterized by , that at least two pistons (44, 44', 66, 66') of the multiple piston cylinder arrangement (42, 42') are arranged parallel to each other or in a row behind each other. [4] Lifting device (10) according to one of claims 2 or 3, characterized by , that the at least two pistons (44, 44', 66, 66') are integrated in a common cylinder housing (58, 68) or each of the at least two pistons (44, 44', 66, 66') is arranged in separate cylinder housings. [5] Lifting device (10) according to any one of claims 1 to 4, characterized by a lifting device (16) accommodating the platform (14) in a plane relative to the frame (12) (E F ) movable receiving sled (30). [6] Lifting device (10) according to one of the preceding claims, characterized by , that the at least one support arm (22, 22') is rotatably connected to the platform (14) at a first end (26) and at least pivotably connected to the frame (12) at a second end (28) arranged opposite to the first end (26), preferably to the movable carriage (30). [7] Lifting device (10) according to one of the preceding claims, characterized by , that the support arm (22, 22') is pivotally connected to the slide (30) by means of a pivot bearing (40), preferably attached to it. [8] Lifting device (10) according to one of the preceding claims, characterized by, that at least one support arm (22, 22') is in each pivot plane (E S ) is adjustable, wherein the pivot plane (E S ) in the mounted state of the lifting device (10) on a vehicle (100) runs essentially perpendicular to a longitudinal side (106) of the vehicle (100). [9] Lifting device (10) according to claim 7 or 8, characterized by , that the pivot bearing (40) has a pivot axis (X) which is parallel to the travel plane (E) F ) of the slide (30) runs and preferably transversely to a direction of travel (R F ) of the sled (30) is aligned. [10] Lifting device (10) according to one of the preceding claims, characterized by , that the lifting device (10) has two support arms (22, 22') wherein the pivot planes (E S) of the support arms (22, 22') preferably run parallel to each other, wherein the support arms (22, 22') are each connected with their first ends (26) to a longitudinal side (48, 48') of the platform (14). [11] Lifting device (10) according to one of the preceding claims, characterized by , that the support arm (22, 22') has a straight-extending profile section (38) with a longitudinal axis (L), wherein a pivot bearing (40) defining the pivot axis (X) for the support arm (22, 22') has a lateral offset (A1) to the longitudinal axis (L). [12] Lifting device (10) according to one of the preceding claims, characterized by , that the drive means (24, 24') interacts with a force application point (46) formed on at least one of the support arms (22, 22'), which is arranged with a lateral offset (A2) to the pivot bearing (40) on the support arm (22, 22'). [13] Lifting device (10) according to claim 12, characterized by, that the point of force application (46) and the pivot bearing (40), with respect to the longitudinal axis (L) of the support arm (22, 22'), are arranged on opposite sides of the longitudinal axis (L). [14] Lifting device (10) according to claim 12 or 13, characterized by , that the multiple piston cylinder arrangement (42, 42') is connected via at least one connecting element (50), in particular strut structure (50'), to the point of force application (46) on the lifting mechanism (20), which is preferably curved or inclined at an angle (α) to the central axis (M) of a piston (44, 44', 66, 66') of the arrangement (42, 42'). [15] Lifting device (10) according to any one of claims 4 to 14, characterized by , that the multiple piston cylinder arrangement (42, 42') is each movably mounted on the slide (30) and coupled to the lifting mechanism (20). [16] Vehicle (100), in particular vehicle (100') for the transport of persons, with - a vehicle chassis (102), and - a lifting device (10) mounted on the vehicle chassis (102), wherein the lifting device (10) is designed according to one of claims 1 to 15. [17] Lifting device for vehicles (100), in particular wheelchair lift, with - a frame (12) that can be mounted on a vehicle (100), - a platform (14) guided on the frame (12), which can be moved back and forth between a retracted and an extended position (S1, S2), and - a lifting device which is configured to move the platform (14) in its extended position (S2), relative to a height level (H) defined by the frame (12), between a raised position (P1) and a lowered position (P2), wherein the lifting device has a lifting mechanism which includes at least one support arm (22, 22') for implementing a lifting movement on the platform (14), wherein the support arm (22, 22') has at least one drive means for generating the lifting movement (S H ) of the platform (14) between the raised and lowered positions, characterized by that the drive means has at least a multi-spindle drive arrangement. [18] Use of a multiple piston cylinder arrangement (42, 42'), in particular a double piston cylinder, or a multiple spindle drive arrangement for moving a platform (14) between a raised and a lowered position (P1, P2) on a vehicle lift device (10) (100) according to any one of claims 1 to 15 or 17.

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