Lifting column

Abstract

The present invention relates to a lifting column (2) comprising five column elements (4, 6, 8, 10, 12) arranged at least partially nested, as well as a first threaded drive (20) for moving the three innermost column elements (8, 10, 12) relative to each other and a second threaded drive (30) for moving the three outermost column elements (4, 6, 8) relative to each other. Furthermore, a coupling tube arrangement (40) is provided which operatively connects the first threaded drive (20) with the second threaded drive (30).

Description

[0001] The present invention relates to a lifting column.

[0002] Lifting columns are known for lifting loads; they typically comprise two or more column elements arranged in a box-like manner. To telescopize the lifting column, i.e., to move the column elements relative to one another, at least one motor is typically provided inside the lifting column. This motor typically drives a helical gear consisting of a threaded spindle and a spindle nut. The stroke of the lifting column is limited by the stroke of the spindle nut on the threaded spindle. To extend the stroke, telescopic threaded spindles or cable pull systems coupled to the helical gear can be used. Alternatively, two helical gears, each driven by a motor, are also used.

[0003] It is an object of the invention to provide an improved lifting column. In particular, it is an object of the invention to provide a lifting column that has a large stroke, is easy to assemble, and has synchronously movable column elements.

[0004] This task is solved by a lifting column according to the independent claim.

[0005] Preferred embodiments are subject of the dependent claims and the following description.

[0006] A first aspect of the invention relates to a lifting column comprising five column elements arranged at least partially in a nested manner, as well as a first screw drive for moving the three innermost column elements relative to one another and a second screw drive for moving the three outermost column elements relative to one another. Furthermore, a coupling tube arrangement is provided which operatively connects the first screw drive to the second screw drive.

[0007] An operative connection within the meaning of the invention is preferably a coupling, in particular a mechanical one. The coupling tube arrangement is therefore at least part of an operative connection between the first and second screw drives, i.e., the first and second screw drives are operatively connected to one another via the coupling tube arrangement. An operative connection is expediently also present when a gear and / or a drive arrangement is interposed, i.e., when, for example, a drive drives one of the screw drives and the coupling tube arrangement directly or indirectly, for example, via (each) a coupling gear.

[0008] A screw drive within the meaning of the invention is preferably an assembly for converting a rotational movement into a translational movement. A screw drive is also referred to as a helical gear and expediently has at least one threaded spindle and a threaded spindle nut that runs on an external thread of the threaded spindle. The threaded spindle is preferably screwed directly into the threaded spindle nut. Alternatively, a screw drive can also be a ball screw drive or a planetary screw drive, in which rolling elements such as balls or planetary rollers roll between the threaded spindle and the threaded spindle nut. A screw drive within the meaning of the invention can alternatively or additionally also have a hollow spindle and a corresponding hollow spindle nut.

[0009] One aspect of the invention is based on the approach of synchronizing two screw drives of a lifting column, each of which serves to generate a relative movement of three column elements, using a coupling tube arrangement. This means that only a single drive arrangement is required to extend or retract the lifting column. Accordingly, the lifting column can be designed more simply than lifting columns with a cable pull system. Furthermore, damping of the column elements can be omitted. In particular, this allows for savings in components. This not only simplifies production but also reduces costs.

[0010] Furthermore, a flexible design of the lifting column is possible. The drive assembly can, for example, be operatively connected to the first or second screw drive or to the coupling tube assembly. Thus, the drive assembly can be arranged in any of the column elements, in particular in the outermost, second-outermost, middle, or second-innermost column element, as required.

[0011] An arrangement in a specific column element within the meaning of the invention is preferably an arrangement on a floor or ceiling of the corresponding column element. An arrangement in a column element is therefore, in particular, an arrangement in this column element in every operating state. For example, a drive arrangement arranged in the innermost column element can, in the retracted state of the lifting column, also be arranged—literally—in the outermost column elements at the same time; however, in the extended state, this drive arrangement is then arranged only in the innermost column element.

[0012] A reliable and space-saving operative connection between the first and second screw drives is achieved by arranging a coupling tube in the coupling tube assembly parallel to the first and second screw drives. The coupling tube is conveniently mounted for rotation within the lifting column, for example, on the third column element.

[0013] The coupling tube arrangement is expediently provided for transmitting torque from one column element to another column element, in particular across at least one of the column elements, for example the middle column element. This means that a torque can be transmitted to the coupling tube at one of the column elements, for example the second innermost column element, and is made available in another of the column elements, for example the second outermost column element. This is expediently possible regardless of how far the lifting column is telescoped, i.e. how far the column elements are displaced relative to one another. The coupling tube arrangement thus enables an operative connection between the first and second screw drive to be realized with a particularly small number of components and is mechanically robust.

[0014] Preferred embodiments of the invention and further developments thereof are described below, which, unless expressly excluded, can be combined with one another as desired and with the aspects of the invention described below.

[0015] A space-saving design can be achieved by having the first and second screw drives each have a telescopic spindle with an internal threaded spindle and an external hollow spindle. A threaded spindle is preferably a shaft with an external thread or helical grooves for guiding rolling elements. Accordingly, a hollow spindle is preferably a hollow shaft with an external thread or helical grooves for guiding rolling elements.

[0016] In addition to the space-saving design of the first and second screw drive, this also enables a very reliable and very precise movement of the innermost and outermost column elements relative to each other.

[0017] For the synchronous movement of the three outermost and innermost column elements relative to one another, a first hollow spindle of the first screw drive is preferably pivotally mounted on the second innermost column element. Alternatively or additionally, a second hollow spindle of the second screw drive is pivotally mounted on the second outermost column element. The hollow spindles are expediently operatively connected via the coupling tube arrangement. This means that a rotation of the first hollow spindle can be transferred to the second hollow spindle via the coupling tube arrangement, or vice versa. The synchronous movement of the column elements relative to one another achieved in this way is perceived as aesthetically pleasing by users.

[0018] A rotary bearing of the hollow spindles on the second innermost or second outermost column element preferably comprises an axial fixing of the hollow spindles on the corresponding column element.

[0019] With such a rotary bearing of the hollow spindles, the respective threaded spindle can be extended or retracted by the hollow spindles each having an internal threaded spindle nut. The threaded spindle nuts can be mounted on the hollow spindles in a rotationally fixed manner or formed integrally with them. The threaded spindle nuts are expediently operatively connected to the respective threaded spindle, for example by engagement of corresponding threads or via corresponding rolling elements. The threaded spindles are expediently arranged so as to be rotatable relative to the respective hollow spindle (and the threaded spindle nut connected to it in a rotationally fixed manner), for example so as to be rotationally fixed to the middle column element or to the outermost column element. The threaded spindles are expediently fixed axially to the middle or outermost column element, for example rigidly connected to it.This has the advantage that the power transmission from the screw drives to the column elements does not have to be carried out via bearings for the screw drive components, especially the hollow spindles and threaded spindles. As a result, small rolling or even plain bearings can also be used for the rotary support of the screw drive components.

[0020] However, it is also conceivable to mount the threaded spindles rotatably on the middle and outermost column elements. In this case, the screw drives preferably each have a spindle driver, expediently for transmitting torque between the hollow spindles and threaded spindles. For example, a spindle driver can be mounted on each of the threaded spindles in a rotationally fixed manner. The hollow spindles expediently have internal spindle profiles on which the spindle drivers are mounted in a rotationally fixed and axially movable manner.

[0021] A profile within the meaning of the invention is preferably a configuration of a surface of a substantially cylindrical body that prevents circumferential movement of a component complementary to the surface and at least partially in contact with the surface, but permits axial movement. In principle, an arrangement on the outside or inside of the body is conceivable. Accordingly, it can be referred to as an outer or inner profile.

[0022] Using the spindle drivers, similar to the coupling tube arrangement, torque can be transmitted from one column element to another. For example, it is conceivable to drive the second threaded spindle, which is rotatably mounted on the outermost column element, using the drive assembly and to transfer the corresponding torque to the second hollow spindle, which is rotatably mounted on the second outermost column element, using the associated spindle driver. The operative connection of the screw drives via the coupling tube arrangement allows the torque to be further transmitted to the first threaded spindle, which is rotatably mounted on the middle column element, and then to the first hollow spindle, using the associated spindle driver.

[0023] A particularly efficient, particularly easy-to-install and space-saving arrangement of the coupling tube assembly in the lifting column can be achieved by rotatably mounting the coupling tube on the central column element. This enables a mechanical, essentially axial play-free and backlash-free connection between the first and second screw drives across the central column element.

[0024] It is also conceivable to couple two similar screw drives. This allows for further effort and cost savings if the first and second screw drives are identical in design. The hollow and threaded spindles of the screw drives can thus both be right-handed.

[0025] Alternatively or additionally, the coupling tube can also have an inner tube profile on which an inner tube driver is mounted in a rotationally fixed and axially movable manner. The inner tube driver expediently serves to transmit torque between the coupling tube and the second threaded drive, in particular the second hollow spindle, or between the coupling tube and a motor-driven shaft. If the coupling tube is motor-driven, its rotation can be transmitted to the second hollow spindle. If, however, the shaft or the second threaded spindle is motor-driven, the rotation of the second hollow spindle or the shaft can be transmitted to the coupling tube.

[0026] The motor-driven shaft is expediently part of the coupling tube assembly. It is preferably mounted axially movably in the coupling tube by means of the inner tube driver and is connected to the coupling tube in a rotationally fixed manner. The inner tube driver is preferably mounted to the shaft in a rotationally fixed manner. Alternatively, the inner tube driver can also be formed integrally with the shaft. It is particularly conceivable for the shaft to have, at least in sections, an outer shaft profile that complements the inner profile of the tube.

[0027] Preferably, the shaft is rotatably mounted in a column element different from the middle one, for example, in the second-outermost column element. Accordingly, in this case, the drive arrangement is preferably also arranged in the second-outermost column element.

[0028] The provision of the shaft allows for the creation of a telescopic coupling tube arrangement. This eliminates the need for the coupling tube to be arranged concentrically with the second screw drive, particularly the second hollow spindle. This allows a certain degree of freedom in the arrangement of the first and second screw drives, as well as the coupling tube arrangement, in the lifting column.

[0029] Alternatively, the second screw drive, in particular the second hollow spindle, can also be operatively connected, in particular rotationally fixed, to the coupling tube via the inner tube driver. The inner tube driver can be mounted rotationally fixed to the second hollow spindle. The coupling tube is expediently arranged coaxially with the second screw drive, in particular the second hollow spindle. This allows for a particularly space-saving arrangement of the coupling tube assembly.

[0030] The same advantage can be achieved if, in an alternative embodiment, the inner pipe driver is part of the second screw drive, in particular the second hollow spindle. The inner pipe driver and the second hollow spindle are expediently formed as a single piece. In particular, the hollow spindle can have, at least in sections, a hollow spindle outer profile complementary to the pipe inner profile.

[0031] To enable the transmission of a rotational movement by means of the coupling tube arrangement across a column element, in particular from the second outermost to the second innermost column element, the coupling tube preferably has a tube outer profile on which an outer tube driver is mounted in a rotationally fixed and axially movable manner. The outer tube driver is expediently part of the coupling tube arrangement and is preferably operatively connected to the first screw drive, in particular the first hollow spindle or the first threaded spindle.

[0032] A second aspect of the invention relates to an X-ray system comprising an X-ray source, an X-ray detector, and a lifting column according to the first aspect of the invention. The X-ray source or the X-ray detector is expediently mounted on the lifting column. The lifting column allows components of the system to be positioned at a short distance from a ceiling or floor. The components can thus be precisely moved relative to one another, regardless of whether they are pulled or pushed for positioning purposes.

[0033] As an alternative to use in an X-ray system, the lifting column according to the first aspect of the invention can also be used in automation systems, i.e., as part of one or more robots. It is also conceivable to use the lifting column in a, possibly mobile, goods or passenger lift.

[0034] The invention is explained in more detail below with reference to figures. Where appropriate, elements with the same function are provided with the same reference numerals. The invention is not limited to the exemplary embodiments illustrated in the figures - not even with regard to functional features. The previous description as well as the following description of the figures contain numerous features, some of which are summarized in the dependent claims. However, a person skilled in the art will also consider these features, as well as all other features disclosed above and in the following description of the figures, individually and combine them to form further useful combinations. In particular, all of the features mentioned can be combined individually and in any suitable combination with the lifting column according to the first aspect of the invention and the X-ray system according to the second aspect of the invention.

[0035] They show, at least partly schematically: Fig. 1 a first example of a lifting column; Fig. 2 a second example of a lifting column; Fig. 3 a third example of a lifting column; and Fig. 4 an example of an X-ray system.

[0036] Fig. 1 shows a first example of a lifting column 2 with five column elements 4, 6, 8, 10, 12 arranged at least partially nested. In particular, a second outermost column element 6 is arranged at least partially in an outermost column element 4, a middle column element 8 is arranged at least partially in the second outermost column element 6, a second innermost column element 10 is arranged at least partially in the middle column element 8, and an innermost column element 12 is arranged at least partially in the second innermost column element 10. The column elements 4, 6, 8, 10, 12 are rotationally fixed relative to one another.

[0037] The column elements 4, 6, 8, 10, 12 can be moved axially relative to one another by means of a first screw drive 20 and a second screw drive 30. The two screw drives 20, 30 advantageously operate complementarily. This means that the first screw drive 20 can move the three innermost column elements 8, 10, 12, and the second screw drive 30 can move the three outermost column elements 4, 6, 8 relative to one another. This makes it possible to increase the stroke compared to conventional lifting columns or at least achieve a comparable stroke with a significantly more robust design.

[0038] A coupling tube arrangement 40 operatively connects the first screw drive 20 to the second screw drive 30. This means that the coupling tube arrangement 40 is part of an operative connection between the first and second screw drives 20, 30. In the present example, this operative connection additionally comprises a drive arrangement 50. The drive arrangement 50 has a motor 52 and optionally a first and / or second gear 54, 56 for transmitting a torque generated by the motor 52 to the first screw drive 20 or the coupling tube arrangement 40.

[0039] The first screw drive 20 has a first hollow spindle 22 and a first threaded spindle 24 arranged at least partially therein. The first hollow spindle 22 can be driven directly by the motor 52, in particular via the first gear 54. Internally, the first hollow spindle 22 has a first threaded spindle nut 26 into which the first threaded spindle 24 is screwed.

[0040] The second screw drive 30 is essentially structurally identical to the first screw drive 20. It has a second hollow spindle 32 and a second threaded spindle 34 arranged at least partially therein. The second hollow spindle can be driven indirectly by the motor 52, namely via the coupling tube arrangement 40. If necessary, the coupling tube arrangement 40 can be operatively connected to the motor 52 via a second gear 56. Internally, the second hollow spindle 32 has a second threaded spindle nut 36 into which the second threaded spindle 34 is screwed.

[0041] For the synchronous movement of the three innermost column elements 8, 10, 12 relative to one another, the first hollow spindle 22 is pivotally mounted on the second innermost column element 10 and axially fixed thereto. The first threaded spindle 24 is non-rotatably mounted on the middle column element 8. A first hollow spindle nut 28 is non-rotatably mounted on the innermost column element 12, into which the first hollow spindle 22 is screwed with an external thread 22a.

[0042] As a result, the first hollow spindle nut 28 - and thus the innermost column element 12 - moves axially along the first hollow spindle 22 - and thus relative to the second innermost column element 10 - when the first hollow spindle 22 rotates as driven by the motor 52, while the first threaded spindle 24 moves out of or into the first hollow spindle 22 - and thereby moves the middle column element 8 relative to the second innermost column element 10.

[0043] For the synchronous movement of the three outermost column elements 4, 6, 8 relative to one another, the coupling tube arrangement 40 has a coupling tube 42 arranged coaxially with the second screw drive 30, in particular the second hollow spindle 32. The coupling tube 42 has an outer tube profile 42a on which an outer tube driver 44 is mounted in a rotationally fixed and axially movable manner. The outer tube driver 44 thus allows the transmission of torque to the coupling tube 42. The outer tube driver 44 is operatively connected to the motor 52, in particular via the second gear 56.

[0044] The coupling tube 42 also has an inner tube profile 42b, on which an inner tube driver 46 is mounted in a rotationally fixed and axially movable manner. The inner tube driver 46 is mounted in a rotationally fixed manner on the second hollow spindle 32. As a result, the coupling tube 42 can transmit a rotation driven by the motor 52 to the second hollow spindle 32.

[0045] The coupling tube 42 is pivotally mounted on the middle column element 8, while the second hollow spindle 32 is pivotally mounted on the second outermost column element 6. The coupling tube arrangement 40 thus serves to transmit torque from the second innermost column element 10 via the middle column element 8 to the second outermost column element 6.

[0046] A second hollow spindle nut 38 is non-rotatably mounted on the middle column element 8, into which the second hollow spindle 32 is screwed with an external thread 32a. The second threaded spindle 34 is non-rotatably mounted on the outermost column element 4.

[0047] As a result, the second hollow spindle nut 38 - and thus the middle column element 8 - moves axially along the second hollow spindle 32 - and thus relative to the second outermost column element 6 - during a rotation of the second hollow spindle 32 driven by the motor 52 and transmitted by the coupling tube arrangement 40, while the second threaded spindle 34 moves out of or in from the second hollow spindle 34 - and thereby moves the outermost column element 4 relative to the second outermost column element 6.

[0048] As an alternative to the illustrated arrangement of the drive assembly 50 in the second innermost column element 10, an arrangement in the second outermost column element 6 is also conceivable. The motor 52, optionally via the first gear 54, is then operatively connected directly to the second hollow spindle 32. The second hollow spindle 32 can transmit a torque thereby generated via the inner tube driver 46 and the coupling tube 42 to the outer tube driver 44. The outer tube driver 44 is expediently operatively connected to the first hollow spindle 22, for example, via the second gear 56.

[0049] The pipe outer profile 42a and / or the pipe inner profile 42b can be formed by a non-circular outer or inner contour of the coupling pipe 42 in the circumferential direction. The coupling pipe 42 expediently has this non-circular outer contour at least over a large part of its length. Expediently, the coupling pipe 42 does not have a non-circular outer contour in the region of its pivot bearing on the central column element 8. A non-circular inner or outer contour can be formed, for example, by an outer or inner shape of the coupling pipe 42 that is oval or angular in cross-section. Alternatively, axially extending grooves or webs, in or on which complementary webs or grooves of the pipe drivers 44, 46 sit or engage, are conceivable. In principle, however, other configurations are also conceivable.

[0050] The lifting column 2 can carry a load (not shown). Fig. In the lifting column 2 shown in Figure 1, it proves advantageous that the load is not supported via the bearings for supporting the components of the first and second screw drives 20, 30 and the coupling tube arrangement 40. Instead, a force flow caused by such a load is supported exclusively via the first and second hollow spindles 22, 32, the first and second threaded spindles 24, 34, and the nuts 26, 28, 36, 38.

[0051] Fig. 2 shows a second example of a lifting column 2 with five column elements 4, 6, 8, 10, 12 which are arranged at least partially in a nested manner and are axially movable relative to one another by means of a first and second screw drive 20, 30. The lifting column 2 differs from the one in Fig. 1 in that the drive arrangement 50 is arranged in the second outermost column element 6 and the coupling tube arrangement 40, in particular the coupling tube 42, is not arranged coaxially with the second screw drive 30.

[0052] Instead, the coupling tube arrangement 40 is arranged separately from the first and second screw drives 20, 30 and is operatively connected to them via the first and second gears 54, 56.

[0053] In particular, the coupling tube arrangement 40 has a shaft 48 that is rotatably mounted on the second outermost column element 6. The shaft 48 is driven by the motor 52 and is operatively connected to the second hollow spindle 32 via the first gear 54. The inner tube driver 46 is non-rotatably mounted on the shaft 48 or formed integrally therewith, so that a rotation of the shaft 48 driven by the motor 52 is transmitted to the coupling tube 42. The outer tube driver 44 is operatively connected to the first hollow spindle 22, in particular via the second gear 56. As a result, a torque can be transmitted from the second outermost column element 6 via the middle column element 8 to the second innermost column element 10.

[0054] The separate arrangement of the coupling tube assembly 40 enables a particularly efficient arrangement of the coupling tube assembly 40 together with the first and second screw drives 20, 30 within the lifting column 2. The first and second screw drives 20, 30 and the coupling tube assembly 40 can, for example, be mounted in a particularly space-saving triangular arrangement.

[0055] In this variant, too, a load is not supported by the bearings for the screw drives 20, 30.

[0056] Fig. 3 shows a third example of a lifting column 2 with five column elements 4, 6, 8, 10, 12 which are arranged at least partially in a nested manner and are movable relative to one another by means of a first and second screw drive 20, 30. In contrast to the column elements 4, 6, 8, 10, 12 shown in Fig. 1 and Fig. In the examples shown in Figure 2, the threaded spindles 24, 34 each have a spindle driver 24a, 34a, which can be mounted on the threaded spindles 24, 34 in a rotationally fixed manner or formed integrally therewith. The spindle drivers 24a, 34a are mounted on an inner spindle profile 22b, 32b of the first and second hollow spindles 22, 32 in a rotationally fixed and axially movable manner. Therefore, the hollow spindles 22, 32 are not operatively connected, in particular rotationally fixed, to the respective threaded spindle 24, 34 via a threaded spindle nut arranged internally therein, mounted in a rotationally fixed manner, or formed integrally therewith, but rather via the spindle drivers 24a, 34a.

[0057] The threaded spindles 24, 34 are rotatably mounted on the middle and outermost column elements 8, 4, respectively. The second threaded spindle 34 is directly connected to the drive assembly 50, which is also arranged in the outermost column element 4.

[0058] The first threaded spindle 24 is operatively connected to the coupling tube 42 in the central column element 8 via a first gear 54. Since both the first threaded spindle 24 and the coupling tube 42 are pivotally mounted on the central column element 8—and thus axially fixed—an external tube driver is not necessary.

[0059] For the synchronous movement of the column elements 4, 6, 8, 10, 12 relative to one another, the threaded spindles 24, 34 are screwed into threaded spindle nuts 26, 36 mounted in a rotationally fixed manner on the second innermost and second outermost column elements 10, 6. When the threaded spindles 24, 34 rotate, the second innermost column element 10 is moved relative to the middle column element 8, and the second outermost column element 6 is moved relative to the outermost column element 4.

[0060] The hollow spindles 22, 32 are screwed into hollow spindle nuts 28, 38 mounted on the middle or innermost column element 8, 12 in a rotationally fixed manner, so that upon rotation of the hollow spindles 22, 32 the innermost column element 12 is moved relative to the second innermost column element 10 and the middle column element 8 is moved relative to the second outermost column element 6.

[0061] The torque introduced by the motor 52 is consequently transmitted by means of the second screw drive 30 from the outermost column element 4 to the second outermost column element 6, by means of the coupling tube arrangement 40 from the second outermost column element 6 to the middle column element 8 and by means of the first screw drive 20 from the middle column element 8 to the second innermost column element 10.

[0062] In Fig. In the example shown in Figure 3, the flow of force is in contrast to the Fig. 1 and Fig. 2, by the bearings of the hollow spindles 22, 32 and threaded spindles 24, 34. For this purpose, the drive arrangement 50, in particular the motor 52, can be arranged in the outermost column element 4. This can facilitate the assembly of the lifting column 2 and / or the power supply of the motor 52, for example, when the lifting column 2 is used as a floor or ceiling stand and the outermost column element 4 stands on the floor or the outermost column element 4 is attached to the ceiling.

[0063] Fig.Figure 4 shows an example of an X-ray room in which an X-ray system 100 with an X-ray source 110 and two X-ray detectors 120, as well as two, in particular five-fold telescopic, lifting columns 2, are arranged. Here, one X-ray detector 120 is integrated into a patient table 130, while the other X-ray detector 120 is part of a grid wall unit and is height-adjustable by means of one of the lifting columns 2. The X-ray source 110 is also mounted so that its height is adjustable by means of the other lifting column 2.

[0064] The lifting columns 2 can generally be used as a tripod, namely in particular as a floor tripod and / or as a ceiling tripod. List of reference symbols 2 lifting columns 4 outermost column element 6 second outermost column element 8 middle column element 10 second innermost column element 12 innermost column element 20 first screw drive 22 first hollow spindle 22a external thread 22b Spindle inner profile 24 first threaded spindle 24a first spindle driver 26 first threaded spindle nut 28 first hollow spindle nut 30 second screw drive 32 second hollow spindle 32a external thread 32b spindle inner profile 34 second threaded spindle 34a second spindle driver 36 second threaded spindle nut 38 second hollow spindle nut 40 Coupling pipe arrangement 42 coupling tube 42a Pipe outer profile 42b Pipe inner profile 44 outer pipe driver 46 inner pipe driver 48 Wave 50 Drive arrangement 52 engine 54 first gearbox 56 second gearbox 100 X-ray system 110 X-ray source 120 X-ray detector 130 patient table

Claims

[1] Lifting column (2), comprising: - five column elements (4, 6, 8, 10, 12) arranged at least in sections in a nested manner; - a first screw drive (20) for moving the three innermost column elements (8, 10, 12) relative to one another; - a second screw drive (30) for moving the three outermost column elements (4, 6, 8) relative to each other; and - a coupling tube arrangement (40) which operatively connects the first screw drive (20) to the second screw drive (30). [2] Lifting column (2) according to claim 1, wherein the first and second screw drive (20, 30) each have a telescopic spindle with an internal threaded spindle (24, 34) and an external hollow spindle (22, 32). [3] Lifting column (2) according to claim 2, wherein a first hollow spindle (22) of the first screw drive (20) is rotatably mounted on the second innermost column element (10) and a second hollow spindle (32) of the second screw drive (30) is rotatably mounted on the second outermost column element (6). [4] Lifting column (2) according to one of claims 2 or 3, wherein the hollow spindles (22, 32) each have an internal threaded spindle nut (26, 36) which is in operative connection with the respective threaded spindle (24, 34). [5] Lifting column (2) according to one of claims 2 or 3, wherein the threaded spindles (24, 34) have a spindle driver (24a, 34a) and the hollow spindles (22, 32) have spindle inner profiles (22b, 32b) on which the spindle drivers (24a, 34a) are mounted in a rotationally fixed and axially movable manner. [6] Lifting column (2) according to one of the preceding claims, wherein a coupling tube (42) of the coupling tube arrangement (40) is rotatably mounted on the central column element (8). [7] Lifting column (2) according to one of the preceding claims, wherein the first screw drive (20) and the second screw drive (30) are identical in construction. [8] Lifting column (2) according to one of the preceding claims, wherein the coupling tube arrangement (40) has an inner tube driver (46) which is mounted on an inner tube profile (42b) of the coupling tube (42) in a rotationally fixed and axially movable manner. [9] Lifting column (2) according to claim 8, wherein the coupling tube arrangement (40) has a motor-driven shaft (48) which is mounted in the coupling tube (42) by means of the inner tube driver (46) for axial movement and is connected to the coupling tube (42) in a rotationally fixed manner. [10] Lifting column (2) according to claim 8, wherein the second screw drive (30) is operatively connected to the coupling tube (42) via the inner tube driver (46). [11] Lifting column (2) according to one of the preceding claims, wherein the coupling tube arrangement (40) has an outer tube driver (44) which is mounted on an outer tube profile (42a) of the coupling tube (42) in a rotationally fixed and axially movable manner.

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