Furniture lifting column

Abstract

To make a lifting / lowering strut that is simple in a structure and has weight compensation.SOLUTION: The application concerned is related to a lifting / lowering strut for furniture, particularly for a table. The lifting / lowering strut has a first element and a second element. The second element is introduced into the first element by at least some kind of a method. The first element has a spindle extended along a longitudinal axis line of the first element, and protruding into the second element by at least some kind of a method. The second element has a rotor mounted rotatably mounted therein, and having at least one rolling body running over or in a striped spiral of the spindle. The rotation of the rotor to the spindle raises linear-motion of the second element to the first element. The second element also has a restraint device for preventing the rotation of the rotor to the spindle in a first state, and releasing the rotation of the rotor to the spindle in a second state. At least one leg spring is clamped between the rotor and the fixing element fixed to the second element, and therefore this leg spring applies pre-stress force to the rotor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lifting column for furniture, in particular a table, which compensates for the weight of the furniture. The present invention also relates to a piece of furniture, in particular a table, having at least one lifting column which compensates for the weight of the furniture. [Background technology]

[0002] The prior art discloses various lifting columns and / or height-adjustable legs for furniture, in particular for tables. The length of the lifting columns and / or legs can be adjusted by a motor or manually. In particular in the case of manual adjustment, it is advantageous if the lifting columns and / or height-adjustable legs have means that make it possible to compensate for the weight of the furniture, in particular the weight of the tabletop.

[0003] U.S. Patent No. 7,658,359, for example, discloses a device for adjusting the height of a table. The table leg includes a first outer column element and a second inner column element, a weight compensation device, a blocking device, and a roller disposed on the inner column element and interacting with a track within the outer column element. The weight compensation device includes, among other things, a spring, a worm wheel for compensating for the variable spring force, and a cable that interacts with the worm wheel and is fixed inside the outer column element. The prestressing of the compression spring acting on the cable attachment can be set using a knob-operable spool. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 7,658,359 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the invention is to create a lifting column belonging to the technical field mentioned at the beginning, which is simple in construction and has weight compensation. [Means for solving the problem]

[0006] This object is achieved by the configuration defined in claim 1. According to the invention, a lifting column comprises a first element and a second element. The second element is at least partially inserted into the first element. The first element includes a spindle extending along the longitudinal axis of the first element and protruding at least partially into the second element. The second element includes a rotor rotatably mounted within the second element and including at least one rolling element running in or on the striated spiral of the spindle. Rotation of the rotor relative to the spindle causes linear movement of the second element relative to the first element. The second element further includes a restraining device that prevents rotation of the rotor relative to the spindle in a first state and releases (i.e., allows) rotation of the rotor relative to the spindle in a second state. At least one leg spring is clamped between the rotor and a fixed element fixed to the second element, and the leg spring applies a prestressing force to the rotor.

[0007] The prestressing force of the at least one leg spring can at least partially compensate for the weight of furniture connected to the lifting column. Furthermore, the use of the at least one leg spring simplifies the construction of the lifting column. Furthermore, the lifting column construction according to the invention requires very little maintenance.

[0008] A lifting column in the present application is understood to be a device that can be placed on the one hand on an underlying surface, in particular the floor, and on the other hand connected to a piece of furniture, the length of which can be changed in order to set the height of the furniture.

[0009] The lifting columns according to the invention are used in particular for tables, where the lifting columns are preferably connected to the table top, and the table preferably has one, two or four lifting columns according to the invention.

[0010] The first and second elements are configured in the form of hollow bodies, and the two elements have the same cross-sectional shape. To allow the second element to be inserted into the first element, the second element has a slightly smaller cross-sectional dimension. The cross-sectional dimensions of the first and second elements are preferably selected so that, when the second element is inserted into the first element, there is a gap of a few millimeters between the elements, in particular a gap of less than 1 cm. The second element is inserted concentrically into the first element, i.e., the longitudinal axis of the first element coincides with the longitudinal axis of the second element.

[0011] The first and second elements preferably have a circular, rectangular or polygonal cross section. The first and second elements are preferably made of a metal or metal alloy, in particular stainless steel or aluminum. The two elements are preferably elongated, i.e., their length is significantly greater than their cross section. The first and second elements preferably each have a length of at least 35 cm, in particular at least 45 cm. The largest dimension of the two elements in cross section is preferably 3 cm, more preferably 5 cm.

[0012] The first element preferably has a closed surface area at its first end, allowing it to be placed on an underlying surface, in particular a floor. The first element is open at its second end, located opposite the first end, allowing the first end of the second element to be introduced into this second end of the first element. At the second end of the second element, located opposite the first end, the second element preferably has means for fastening the second element to a piece of furniture. These means are preferably in the form of holes or slots for screws or bolts.

[0013] The length adjustment of the lifting column can be achieved by moving the second element into and / or out of the first element. This length adjustment allows the height of the furniture connected to the lifting column to be set. Thus, depending on the length setting of the lifting column, the second element is introduced into the first element over a long or short part of its length.

[0014] The spindle is preferably centrally located on the first element and extends from the first end to the second end of the first element. Thus, the spindle extends along the longitudinal axis of the first element. The spindle may extend along the entire length of the first element, i.e., from its first end to its second end. However, the spindle preferably extends only a portion of the length of the first element.

[0015] The spindle preferably has a high-helix thread. In the following applications, the term "high-helix thread" is understood to mean a thread with a pitch (helix height) of at least 10 mm, preferably at least 20 mm. The spindle preferably has one helix. However, the spindle can alternatively have multiple helices, in particular two helices.

[0016] The rotor is preferably rotatably mounted to the second element via a rolling bearing, so that the rotor can rotate relative to the second element. The rotor is oriented so that it can rotate about the longitudinal axis of the second element. At least one rolling element of the rotor is preferably arranged at an angle corresponding to the pitch angle of the spindle. The rotor preferably has two or more rolling elements, in particular three rolling elements, each arranged at an angle of 120° relative to one another relative to the circumferential direction of the rotor.

[0017] Rotation of the rotor means that at least one rolling element travels in or on the streaky spiral of the spindle, causing a linear displacement of the rotor relative to the spindle. Since the rotor is rotatably mounted on a second element, displacement of the rotor relative to the spindle also causes a linear displacement of the second element relative to the first element.

[0018] When the restraining device prevents the rotor from rotating, it can prevent unintentional length adjustment of the lifting column. When the lifting column is fixed to the furniture, the restraining device remains in the first state and transitions to the second state only when the height of the furniture is adjusted. To switch between the first and second states (and vice versa), the restraining device preferably has an actuating element, in particular a lever or button, that can be operated by a person.

[0019] The length adjustment of the lifting column according to the present invention is preferably performed manually. This means that a person adjusts the length by pulling the second element out of the first element or pushing the second element into the first element. When a piece of furniture is connected to the lifting column, the action of pulling the furniture upward or pushing it downward adjusts the length of the lifting column and ultimately the height of the furniture. In the first state, the restraining device prevents the rotor from rotating, thus preventing the length adjustment of the lifting column and the height adjustment of the furniture connected to the lifting column.

[0020] However, alternatively, the rotor can be rotated by an electrical or electromechanical drive, thereby achieving automatic length adjustment of the lifting column and automatic height adjustment of furniture connected to the lifting column.

[0021] The fixed element is preferably fixed to the second element, i.e. it cannot rotate about the longitudinal axis of the second element, and a first leg of at least one leg spring is connected to or abuts against the fixed element, while a second leg is connected to the rotor in a rotationally fixed manner.

[0022] The leg spring has two legs with multiple windings of the spring disposed between them, and at least one leg spring is preferably disposed within the second element such that the longitudinal axis of the leg spring coincides with the longitudinal axis of the second element.

[0023] The prestressing force of the leg springs exerts a torque on the rotor. This torque causes the rotor to rotate in one direction when the rotor's rotation is released by the restraining device. The leg springs are arranged so that the prestressing force exerts a torque on the rotor, resulting in the second element moving away from the first element, i.e., increasing the length of the lifting column. The second element is subjected to a force directed in a corresponding direction. When the lifting column is used as intended, the first element rests on an underlying surface, particularly a floor, with the longitudinal axes of the first and second elements perpendicular to the underlying surface. Thus, the longitudinal axes of the first and second elements are oriented essentially parallel to the direction of gravity. Thus, the force acting on the second element is directed essentially vertically upward. This force counteracts the weight of furniture connected to the lifting column. This allows for at least partial compensation for the weight of the furniture, particularly facilitating the lengthening of the lifting column and the height of the furniture. Therefore, by properly setting the prestressing force of the leg springs, it is possible to fully compensate for the weight of the furniture connected to the lifting column. In this case, even when the restraining device is in the second state, the weight and the force acting on the second element cancel each other out, so that the height of the furniture without the action of an external force is not adjusted.

[0024] The at least one rolling element is preferably configured in the form of a ball, a cylindrical roller, a tapered roller or a barrel roller.

[0025] If the at least one rolling element is configured in the form of a ball or a cylindrical roller, the at least one rolling element runs within or engages with the corrugated spiral. If the at least one rolling element is configured in the form of a tapered roller or a barrel roller, the at least one rolling element preferably runs on the corrugated spiral of the spindle.

[0026] The fixing element is preferably movable in the form of an arc around the longitudinal axis of the leg spring for the purpose of setting the prestress force of the at least one leg spring.

[0027] The circular movement of the fixing element allows the prestress force of the leg spring, which corresponds to the spring force, to be set. The fixing element here has a means for preventing the fixing element from rotating, thereby maintaining the set prestress force. This means in particular comprises a lever or handle that can be operated by a person. Furthermore, the second element preferably has a setting means for moving the fixing element in a circular manner around the longitudinal axis of the leg spring.

[0028] The fixed element is preferably arranged on a worm wheel which can be rotated by a worm which is connected in a rotationally fixed manner to the second element.

[0029] This results in a particularly simple embodiment of the fixing element, which can move in a circular manner around the longitudinal axis of the leg spring. Furthermore, due to the self-locking action inherent in the worm gear, it is possible to dispense with additional measures aimed at preventing the circular movement of the fixing element around the longitudinal axis of the leg spring.

[0030] The first and second elements preferably have circular cross sections, with the second element having a smaller diameter than the first element.

[0031] The second element is preferably guided linearly within the first element by at least one linear guide, which may prevent the second element from rotating within the first element. The second element is preferably guided within the first element by two or more linear guides, in particular by two, three, or four linear guides. The linear guides may be, for example, in the form of pins running in grooves or in the form of roller guides.

[0032] The second element preferably has at least one rolling bearing, the outer ring of which is introduced into the groove of the first element to form at least one linear guide, thereby providing a space-saving linear guide with very low resistance in a simple manner.

[0033] The rolling bearings used are preferably ball bearings, although cylindrical roller bearings or needle bearings can alternatively be used. The second element preferably has a plurality of circumferentially distributed rolling bearings, which are introduced into a corresponding number of grooves in the first element.

[0034] In a preferred embodiment, the first element has three rolling bearings, each arranged at an angle of 120° relative to one another around the longitudinal axis of the second element.

[0035] In a further preferred embodiment, two of the three rolling bearings are arranged at an angle of 90° to each other, and these two rolling bearings are each arranged at an angle of 135° to the third rolling bearing around the longitudinal axis of the second element. In this embodiment, the first element preferably has eight grooves, each arranged at an angle of 45° to each other around the longitudinal axis of the first element. This allows the second element to be introduced into the first element at eight different angular positions.

[0036] The rotor is preferably connected within the second element to a hollow shaft which extends coaxially to the second element up to a second end of the second element, this second end not being introduced into the first element, the hollow shaft having a toothed arrangement in the region of the second end of the second element.

[0037] In the first state, the arresting device preferably engages the toothed arrangement via a rack fixed to the second element or a gear connected in a rotationally fixed manner to the second element. This means that the rotating shaft, and therefore the rotor connected to the rotating shaft, cannot rotate. In the second state, the rack or gear can be lifted, pushed, or pivoted away from the toothed arrangement, thereby releasing the rotation of the hollow shaft and rotor.

[0038] Furthermore, the toothed arrangement can be used to synchronize the length adjustment of several lifting columns, the latter in each case using gears or bevel gears, in each case connected by at least one shaft that engages with the toothed arrangement of the respective lifting column.

[0039] The thread helix of the spindle preferably has a variable pitch, which makes it possible to compensate for different leg spring forces depending on the depth to which the second element is inserted into the first element.

[0040] The movement of the second element relative to the first element rotates the rotor around the spindle. This means that depending on the position of the second element relative to the first element, the helical spring is more or less stressed, which results in a variation in the spring force experienced by the rotor, or the torque caused thereby. Despite this fact, the force exerted by the leg spring on the rotor, and therefore the second element, can be made constant by using a corresponding change in the pitch of the corrugated helix. In areas where the leg spring is less stressed and therefore the applied spring force is low, the pitch of the corrugated helix is ​​smaller than in areas where the level of stress on the leg spring is higher, and therefore the spring force is higher.

[0041] The at least one rolling element is preferably a cylindrical, tapered or barrel roller configured in the form of a rolling bearing, in which case the outer ring forms a cylindrical, tapered or barrel roller and runs in or on the streaky spiral of the spindle. This arrangement makes it possible to realize a simple, low-maintenance configuration of the at least one rolling element with very low rolling resistance.

[0042] In this embodiment, the outer ring of the rolling bearing thus forms the rolling elements that run in or on the spiral of the spindle. The rolling elements, designed in the form of a rolling bearing, can thus be connected to the rotor via their inner ring. The outer ring has a shape that corresponds to the shape of the rolling elements.

[0043] The rolling bearings used are preferably ball bearings, although cylindrical roller bearings or needle bearings can alternatively be used. The outer ring of the rolling bearing preferably has a convex surface running therearound that complements the profile of the spiral, so that at least one rolling element engages particularly effectively with the spiral of the spindle.

[0044] The leg springs, in particular two leg springs, are preferably clamped in a parallel state between the rotor and the fixed element, meaning that all of the leg springs have one leg fixed to the rotor while the other leg abuts or is connected to the fixed element.

[0045] This arrangement makes it possible to increase the prestressing force that the rotor is subjected to by the leg springs.

[0046] The present invention also relates to a piece of furniture comprising at least one lifting column as described above and having at least one furniture element fixed to the at least one lifting column, preferably a table, in which case the furniture element to which the at least one lifting column is fixed is a tabletop.

[0047] The furniture preferably has two or more lifting columns, in particular two or four lifting columns, for example, the furniture may be a height-adjustable desk with two lifting columns fixed to a rectangular top.

[0048] The shaft is preferably attached to the furniture element, the shaft having a bevel gear which engages in a tooth formation on the hollow shaft of at least one lifting column.

[0049] This shaft can synchronize the rotation of the rotors of several lifting columns fixed to the furniture element. The shaft preferably has bevel gears on both ends, so that the shaft can synchronize the rotation of the rotors of two lifting columns fixed to the furniture element. If three or more lifting columns are fixed to the furniture element, multiple shafts with two bevel gears are also used accordingly.

[0050] The shaft is preferably attached to the furniture element by a holder, which has a double-wrap spring brake acting on the shaft, which functions as a restraining device since it can prevent and release rotation of the hollow shaft and thus of the rotor connected to it. The holder preferably has an actuating element, for example a lever, which can release the braking action that the shaft receives from the double-wrap spring brake.

[0051] The crankshaft is preferably attached to the furniture element, and the crankshaft can drive the worm, which simplifies height adjustment of the at least one furniture element, as this can be achieved by rotation of the crankshaft.

[0052] Further advantageous embodiments and configuration combinations of the invention can be gleaned from the following detailed description and the entire claims.

[0053] The following drawings are used to explain exemplary embodiments. [Brief explanation of the drawings]

[0054] [Figure 1] 1 shows a cross-sectional view of one embodiment of a lifting column according to the present invention. [Figure 2] 2 shows a perspective view of the lifting column according to FIG. 1; [Figure 3] FIG. 10 shows a detailed specific view of the second end of the second element. [Figure 4a] 1 shows a detailed specific view of a second embodiment of a lifting column according to the invention, with rolling elements designed in the form of balls. [Figure 4b] 1 shows a detailed specific view of a second embodiment of a lifting column according to the invention, with rolling elements designed in the form of balls. [Figure 5a] 1 shows a detailed specific view of a third embodiment of a lifting column according to the invention, with rolling elements designed in the form of tapered rollers. [Figure 5b] 1 shows a detailed specific view of a third embodiment of a lifting column according to the invention, with rolling elements designed in the form of tapered rollers. DETAILED DESCRIPTION OF THE INVENTION

[0055] In the figures, like parts are generally provided with like reference symbols.

[0056] 1 shows a cross-sectional view of one embodiment of a lifting column 1 according to the invention. The lifting column 1 comprises a first element 2 surrounding a first wall 6 which encloses an interior space. A second element 3 having a second enclosing wall 7 is at least partially introduced into the first element 2, i.e., into the interior space of the first element 2. A first end of the second element 3 is arranged within the first element 2, and a second end of the second element 3 is arranged opposite the first end and protrudes from the first element.

[0057] In the embodiment shown, the two elements 2, 3 have a circular cross section, with the diameter of the second element 3 being smaller than the diameter of the first element 2. The second element 3 can be linearly displaced in the first element 2. This means that the second element 3 can move linearly within the first element along the longitudinal axis A of the first element. The second element 3 has the same longitudinal axis A as the first element 3.

[0058] The second element 3 is displaceably mounted on the first element 2 via a linear guide. On the side of the first wall 2 facing the interior space, the linear guide has grooves 19.1, 19.2 in which run the outer rings of the rolling bearings 18.1, 18.2 located at the first end of the second element 3. In the illustrated embodiment, the first element has eight grooves 19.1, 19.2, only two of which are shown in FIG. 1, which are distributed on the first wall 6 offset by 45° from each other around the longitudinal axis A. The second element 3 also has three rolling bearings 18.1, 18.2, only two of which are shown in FIG. 1. The first and second rolling bearings 18.1, 18.2 are arranged at an angle of 135° from each other around the longitudinal axis A. Meanwhile, a third rolling bearing (not shown here) is in each case arranged at an angle of 90° to the first rolling bearing 18.1 and the second rolling bearing 18.2.

[0059] The first element 2 also has a closed surface area 24 at its first end. This closed surface area 24 allows the first element 2 to be placed on the floor. A spindle 4 is fixed centrally within this closed surface area 24. The spindle 4 extends along the longitudinal axis A of the first element 2, but does not extend completely to the second end of the first element. This means that the spindle 4 does not protrude from the interior space of the first element 2. The spindle 4 has a variable-pitch rib helix 5. The pitch of the rib helix 5 decreases from the first end of the spindle 4 to its second end.

[0060] A rotor 8 is arranged in the region of the first end of the second element 3. The rotor 8 is rotatably mounted on the second element 3, so that it cannot be displaced relative to the second element 3 but can rotate freely about its longitudinal axis A. The rotor 8 has arranged thereon three rolling elements 9.1 (only one is shown in FIG. 1 ) designed in the form of cylindrical rollers and engaging in the corrugation spiral 5 of the spindle 4. The rolling elements 9.1 are mounted at an angle to the rotor 8, so that they can engage in the corrugation spiral 5 essentially without play. As a result of the engagement of the rolling elements 9.1 in the corrugation spiral 5, rotation of the rotor 8 causes the second element 3 to move linearly relative to the first element 2.

[0061] In the region of the second end, the second element 3 has two fixing elements 15.1, 15.2. Two leg springs 14.1, 14.2 are fastened between the fixing elements 15.1, 15.2 and the rotor 8. The leg springs 14.1, 14.2 are rotationally fixed and secured to the rotor 8 and their respective fixing elements 15.1, 15.2. The leg springs 14.1, 14.2 apply a prestressing force to the rotor 8. This prestressing force imparts a torque to the rotor 8. The leg springs 14.1, 14.2 are prestressed here such that the torque rotates the rotor 8 in a direction that moves the second element 3 away from the first element 2. Therefore, when the lifting column 1 is standing on the floor, the prestressing force increases the length of the lifting column 1. This prestressing force can therefore compensate for the weight of furniture attached to the lifting column 1. That is, the prestressing force is selected to essentially correspond to the weight of the furniture connected to the lifting column 1. This allows a person to set the height of the furniture relatively easily without exerting a great deal of force.

[0062] Since the leg springs 14.1, 14.2 are rotated more or less from their rest position by the rotation of the rotor 8, the prestressing force that the rotor 8 is subjected to by the leg springs 14.1, 14.2 varies depending on the position of the rotor 8 along the spindle 4. In order that the prestressing force that the second element 3 is subjected to by the rotor 8 remains essentially constant at any position of the rotor 8 along the length of the spindle 4, the spindle 4 has the aforementioned variable striation helix pitch.

[0063] The worm wheel 16 is arranged in the region of the second end of the second element 3 and has fixing elements 15.1, 15.2 connected to it. The worm wheel 16 can be rotated by rotating the worm 15 (see FIG. 3). This rotation causes the fixing elements 15.1, 15.2 to rotate simultaneously, so that the prestressing forces of the leg springs 14.1, 14.2 can be changed.

[0064] The rotor 8 is connected to a hollow shaft 12 that extends toward the second end of the second element 3 within the windings of the leg springs 14.1, 14.2. The hollow shaft 12 has a toothed arrangement 13 in the region of the second end of the second element 3. A bevel gear 11 is engaged with this toothed arrangement 13. The bevel gear 11 and the toothed arrangement 13 together form a restraining device 10 that prevents rotation of the rotor 8 relative to the spindle 4 in a first state and releases this rotation in a second state. In the first state, rotation of the bevel gear 11 is prevented, and in the second state, rotation of the bevel gear 11 is released. This can be achieved by providing a suitable mechanism. For example, the bevel gear 11 can be connected to a shaft (not shown) with which a double-wound spring brake interacts.

[0065] A fastening element 21 is arranged at the second end of the second element 3, by means of which the lifting column 1 can be fastened to a piece of furniture, in particular to a tabletop. Furthermore, a flange is arranged in the region of the second end of the first element 2.

[0066] 2 shows a perspective view of the lifting column according to FIG. 1, with the first wall 6 and the second wall 7 omitted for illustrative reasons. This view clearly shows the arrangement of the three rolling bearings 18.1, 18.2, 18.3 which, together with the grooves 19.1, 19.2 of the first element 2, form a linear guide. It also clearly shows the inclined arrangement of the rolling elements 9.1, 9.2 of the rotor 8, which are designed in the form of cylindrical rollers and engage in the ribs 5 of the spindle 4.

[0067] 2, in contrast to the cross-sectional view of Figure 1, more effectively shows the worm wheel 16. The worm 17 is held rotationally fixed relative to the second element 3 by a holder 22.

[0068] Figure 3 shows a detailed perspective view of the second end of the second element 3. This figure clearly shows the worm 17 engaged with the worm wheel 16. The worm wheel 17 has a hexagonal socket drive 25 via which the worm 17 can be rotated via a hexagonal key.

[0069] Bevel gear 11 is rotatably mounted within cover 23 and engages tooth formation 13 on hollow shaft 12. Bevel gear 11 has a central bore 26 that allows bevel gear 17 to engage a shaft (not shown).

[0070] 4a and 4b show detailed views of a second embodiment of a lifting column 1 according to the invention, in which the rolling elements 9.1-9.3 are designed in the form of balls. FIG. 4a shows a perspective view of a spindle 4 with three rib spirals 5.1-5.3, through which each rolling element 9.1-9.3, each designed in the form of a ball, runs. It can be seen that the three rolling elements 9.1-9.3 are in each case arranged at an angle of 120° to one another, which is clearly shown in the cross-section of FIG. 4b. The rib spirals 5.1-5.3 of the spindle 4 are round in cross section, so that the rolling elements 9.1-9.3, designed in the form of balls, can run through them with as little play as possible.

[0071] 5a and 5b show detailed views of a third embodiment of a lifting column 1 according to the invention, in which the rolling elements 9.1-9.3 are designed in the form of tapered rollers. Fig. 5a shows a perspective view of the spindle 4 with the rolling elements 9.1-9.3, while Fig. 5b shows a cross-sectional view. These rolling elements 9.1-9.3 operate in the spirals 5.1-5.3 of the spindle 4, which are in the form of areas on the surface of the spindle 4. Each rolling element 9.1-9.3, designed in the form of a tapered roller, has a pin 27.1-27.3, via which the rolling elements 9.1-9.3 are connected to the rotor 8.

Claims

1. A lifting column for furniture, comprising: a first element; and a second element at least partially introduced into the first element, the first element having a spindle extending along a longitudinal axis of the first element and protruding at least partially into the second element; the second element having a rotor rotatably mounted on the second element and having at least one rolling element running in or on a serrated spiral of the spindle, rotation of the rotor relative to the spindle causing linear movement of the second element relative to the first element; the second element having a constraint device that prevents rotation of the rotor relative to the spindle in a first state and allows rotation of the rotor relative to the spindle in a second state; A lifting column, characterized in that at least one leg spring is attached between the rotor and a fixed element fixed to the second element, the leg spring applying a prestressing force in the form of a torque to the rotor.

2. 2. The lifting column according to claim 1, wherein the at least one rolling element is configured in the form of a ball, a cylindrical roller, a tapered roller, or a barrel roller.

3. 3. A lifting column according to claim 1 or 2, characterized in that, for the purpose of setting the prestress force of the at least one leg spring, the fixing element is movable in an arc around the longitudinal axis of the leg spring.

4. 4. A lifting column according to claim 3, characterized in that the fixed element is arranged on a worm wheel, the worm wheel being rotatable by a worm fixedly connected to the second element.

5. 5. A lifting column according to any one of claims 1 to 4, characterized in that the first element and the second element have a round cross section, the second element having a smaller diameter than the first element.

6. 6. A lifting column according to any one of claims 1 to 5, characterized in that the second element is linearly movably guided within the first element by at least one linear guide.

7. 7. A lifting column according to claim 6, characterized in that the second element has at least one rolling bearing, the outer ring of which is introduced into a groove of the first element to form the at least one linear guide.

8. 8. A lifting column according to claim 1, characterized in that the rotor is connected to a hollow shaft which extends within the second element, coaxially relative to the second element, to a second end of the second element, the second end not being introduced into the first element, and the hollow shaft has a toothed arrangement in the region of the second end of the second element.

9. 9. A lifting column according to any one of claims 1 to 8, characterized in that the sinuous spiral of the spindle has a variable pitch.

10. 10. A lifting column according to any one of claims 1 to 9, characterized in that the at least one rolling element is a cylindrical roller, a tapered roller or a barrel roller configured in the form of a rolling bearing, and the outer ring of the rolling bearing forms a cylindrical roller, a tapered roller or a barrel roller and runs within or on the corrugated spiral of the spindle.

11. 11. A lifting column according to any one of claims 1 to 10, characterized in that several leg springs, in particular two leg springs, are clamped in parallel between the rotor and a fixed element.

12. 12. A piece of furniture comprising at least one lifting column according to any one of claims 1 to 11 and a furniture element to which the second element of the lifting column is fixed.

13. 13. Furniture according to claim 12, when dependent on claim 8, characterized in that the furniture element is fitted with a shaft, said shaft having a bevel gear which engages with the toothed arrangement of the hollow shaft of at least one lifting column.

14. 14. Furniture according to claim 13, characterized in that the shaft is attached to the furniture element by a holder, the holder having a double-wound spring brake acting on the shaft.

15. 15. Furniture according to claim 13 or 14, when dependent on claim 4, characterized in that a crankshaft is attached to the furniture element, said crankshaft being able to drive said worm.

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