Lifting column for a piece of furniture

Abstract

The present application relates to a lifting column for a piece of furniture, in particular for a table. The lifting column comprises a first element and also a second element. The second element is introduced at least some way into the first element. The first element has a spindle, which extends along the longitudinal axis of the first element and projects at least some way into the second element. The second element has a rotor, which is mounted in a rotatable manner in it and has at least one rolling body, which runs in or on a thread helix of the spindle. A rotation of the rotor relative to the spindle gives rise to a linear movement of the second element relative to the first element. The second element also has an arresting device, which, in a first state, blocks the rotation of the rotor relative to the spindle and, in a second state, frees the rotation of the rotor relative to the spindle. At least one leg spring is clamped in between the rotor and a fastening element, which is fastened on the second element, and this leg spring therefore subjects the rotor to a prestressing force.

Claims

1. A lifting column for a piece of furniture comprising: a first element and a second element, which is introduced at least partially into the first element, wherein the first element has a spindle, which extends along the longitudinal axis of the first element and projects at least some way into the second element, and wherein the second element has a rotor, which is mounted in a rotatable manner in the second element and has at least one rolling body, which runs in or on a thread helix of the spindle, wherein a rotation of the rotor relative to the spindle gives rise to a linear movement of the second element relative to the first element, wherein the second element has an arresting device, which, in a first state, blocks the rotation of the rotor relative to the spindle and, in a second state, frees the rotation of the rotor relative to the spindle, wherein at least one leg spring is clamped in between the rotor and a fastening element, which is fastened on the second element, the at least one leg spring subjecting the rotor to a prestressing force.

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

3. The lifting column according to claim 1, wherein for the purpose of setting the prestressing force of the at least one leg spring, the fastening element can be moved in the form of an arc of a circle around the longitudinal axis of the leg spring.

4. The lifting column according to claim 3, wherein the fastening element is arranged on a worm wheel, which may be rotated by means of a worm connected in a rotationally fixed manner to the second element.

5. The lifting column according to claim 1, wherein the first element and the second element have a round cross section, and wherein the second element has a smaller diameter than the first element.

6. The lifting column according to claim 1, wherein the second element is guided in a linearly movable manner within the first element by at least one linear guide.

7. The lifting column according to claim 6, wherein the second element has at least one rolling bearing, and wherein an outer ring of the rolling bearing is introduced into a groove of the first element in order to form the at least one linear guide.

8. The lifting column according to claim 1, wherein the rotor is connected to a hollow shaft which extends within the second element, coaxially in relation to the same, to a second end of the second element, this second end not being introduced into the first element, and wherein the hollow shaft has a toothing formation in the region of the second end of the second element.

9. The lifting column according to claim 1, wherein the thread helix of the spindle has a variable pitch.

10. The lifting column according to claim 1, wherein the at least one rolling body is a cylindrical roller, tapered roller or barrel roller configured in the form of a rolling bearing, and wherein an outer ring of the rolling bearing forms the cylindrical roller, tapered roller or barrel roller and runs in or on the thread helix of the spindle.

11. The lifting column according to claim 1, wherein a plurality of leg springs are clamped in in a parallel state between the rotor and fastening element.

12. A piece of furniture having at least one lifting column comprising: a first element and a second element introduced at least partially into the first element; the second element being fastened to a furniture element; the first element having a spindle extending along a longitudinal axis of the first element and projecting at least partially into the second element; the second element having a rotor mounted in a rotatable manner in the second element and having at least one rolling body, which runs in or on a thread helix of the spindle; wherein a rotation of the rotor relative to the spindle gives rise to a linear movement of the second element relative to the first element; the second element having an arresting device, which, in a first state, blocks rotation of the rotor relative to the spindle and, in a second state, frees rotation of the rotor relative to the spindle, and at least one leg spring being clamped in between the rotor and a fastening element, which is fastened on the second element, the at least one leg spring subjecting the rotor to a prestressing force.

13. The piece of furniture according to claim 12, wherein a shaft is fitted on the furniture element, the shaft having a bevel wheel engaging with a toothing formation of a hollow shaft of the at least one lifting column in the region of the second end of the second element, the rotor being connected to the hollow shaft which extends within the second element, coaxially in relation to the same, to a second end of the second element, the second end not being introduced into the first element.

14. The piece of furniture according to claim 13, wherein the shaft is fitted on the furniture element by means of a holder, and wherein the holder has a double wrap spring brake which acts on the shaft.

15. The piece of furniture according to claim 13, wherein the fastening element is arranged on a worm wheel which may be rotated by means of a worm connected in a rotationally fixed manner to the second element, a crankshaft being fitted on the furniture element, and configured to drive the worm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) in the drawings, which are used for the purpose of explaining the exemplary embodiment:

(2) FIG. 1 shows a sectional illustration of one embodiment of a lifting column according to the invention;

(3) FIG. 2 shows a perspective view of the lifting column according to FIG. 1;

(4) FIG. 3 shows a detail-specific view of the second end of the second element;

(5) FIGS. 4a and 4b show detail-specific views of a second embodiment of a lifting column according to the invention, having rolling bodies designed in the form of balls; and

(6) FIGS. 5a and 5b show detail-specific views of a third embodiment of a lifting column according to the invention, having rolling bodies designed in the form of tapered rollers.

(7) In the figures, in principle, like parts are provided with like reference signs.

WAYS OF IMPLEMENTING THE INVENTION

(8) FIG. 1 shows a sectional illustration of one embodiment of a lifting column 1 according to the invention. The lifting column 1 comprises a first element 2, which has an encircling first wall 6, which encloses an interior space. A second element 3 with a second encircling wall 7 is introduced at least partially into the first element 2, that is to say into the interior space of the first element 2. A first end of the second element 3 is located within the first element 2, whereas a second end of the second element 3, this second end being located opposite the first end, projects out of the first element.

(9) In the case of the embodiment shown, the two elements 2, 3 have a round cross section, wherein the diameter of the second element 3 is smaller than the diameter of the first element 2. The second element 3 can be displaced linearly in the first element 2. This means that the second element 3 can be moved linearly in the first element along a longitudinal axis A of the first element. The second element 3 has the same longitudinal axis A as the first element 3.

(10) The second element 3 is mounted in a displaceable manner in the first element 2 via linear guides. On that side of the first wall 2 which is directed towards the interior space, the linear guides have grooves 19.1, 19.2, in which a respective outer ring of rolling bearings 18.1, 18.2, which are arranged at a first end of the second element 3, run. In the case of the embodiment shown, the first element has eight grooves 19.1, 19.2, of which FIG. 1 shows just two, which are distributed on the first wall 6 in a state in which they are offset in each case through 45° in relation to one another about the longitudinal axis A. The second element 3 also has three rolling bearings 18.1, 18.2, of which FIG. 1 shows just two. The first rolling bearing 18.1 and the second rolling bearing 18.2 are located at an angle of 135° in relation to one another about the longitudinal axis A, whereas the third rolling bearing (not visible here) is located in each case at an angle of 90° relative to the first rolling bearing 18.1 and to the second rolling bearing 18.2.

(11) The first element 2 also has a closed surface area 24 at its first end. The first element 2 can be positioned on a floor by means of this closed surface area 24. At this closed surface area 24, a spindle 4 is fastened centrally within the first element 2. The spindle 4 extends along the longitudinal axis A of the first element 2, but not all the way to the second end of the first element. This means that the spindle 4 does not project out of the interior space of the first element 2. The spindle 4 has a thread helix 5 of variable pitch. The pitch of the thread helix 5 decreases from the first end of the spindle 4 to the second end thereof.

(12) A rotor 8 is arranged in the region of the first end of the second element 3. The rotor 8 is mounted in a rotatable manner on the second element 3, and this allows the rotor to rotate freely about the longitudinal axis A, although it cannot be displaced relative to the second element 3. The rotor 8 has arranged on it three rolling bodies 9.1 (of which FIG. 1 shows just one), which are designed in the form of cylindrical rollers and engage in the thread helix 5 of the spindle 4. The rolling bodies 9.1 are fitted at an angle relative to the rotor 8, and the rolling bodies can therefore engage in an essentially play-free manner in the thread helix 5. As a result of the rolling bodies 9.1 engaging in the thread helix 5, a rotation of the rotor 8 causes the second element 3 to move linearly relative to the first element 2.

(13) In the region of the second end, the second element 3 has two fastening elements 15.1, 15.2. Two leg springs 14.1, 14.2 are clamped in between the fastening elements 15.1, 15.2 and the rotor 8. The leg springs 14.1, 14.2 are fastened in a rotationally fixed manner to the rotor 8 and also to the respective fastening element 15.1, 15.2. The leg springs 14.1, 14.2 subject the rotor 8 to a prestressing force. This prestressing force subjects the rotor 8 to a torque. The leg springs 14.1, 14.2 here are prestressed such that the torque rotates the rotor 8 in the direction which causes the second element 3 to move out of the first element 2. If the lifting column 1 is standing on a floor, the prestressing force therefore causes the length of the lifting column 1 to increase. The prestressing force, then, can compensate for the weight of a piece of furniture fastened on the lifting column 1. That is to say that the prestressing force is selected such that it corresponds essentially to the weight of the piece of furniture connected to the lifting column 1. This allows a person to set the height of the piece of furniture relatively straightforwardly and without any great amount of force being applied.

(14) Depending on the position of the rotor 8 along the spindle 4, the prestressing force to which the rotor 8 is subjected by the leg springs 14.1, 14.2 differs, since the leg springs 14.1. 14.2 are rotated out of their rest position to a greater or lesser extent by the rotation of the rotor 8. In order for the prestressing force to which the second element 3 is subjected by the rotor 8 to be kept essentially constant in any position of the rotor 8 along the length of the spindle 4, the spindle 4 has the aforementioned variable thread-helix pitch.

(15) A worm wheel 16 is arranged in the region of the second end of the second element 3 and has the fastening elements 15.1, 15.2 connected to it. The worm wheel 16 can be rotated by virtue of a worm 15 (see FIG. 3) being rotated. This rotation makes it possible to vary the prestressing force of the leg springs 14.1, 14.2, since the fastening elements 15.1, 15.2 are rotated at the same time.

(16) The rotor 8 is connected to a hollow shaft 12, which extends, within the windings of the leg springs 14.1, 14.2, in the direction of the second end of the second element 3. The hollow shaft 12 has a toothing formation 13 in the region of the second end of the second element 3. A bevel wheel 11 engages in this toothing formation 13. The bevel wheel 11 and the toothing formation 13 together form an arresting device 10, which, in a first state, blocks the rotation of the rotor 8 relative to the spindle 4 and, in a second state, frees this rotation. In the first state, the rotation of the bevel wheel 11 is blocked and, in the second state, it is freed. This can be achieved by a suitable mechanism being provided. For example, the bevel wheel 11 can be connected to a shaft (not shown) with which a double wrap spring brake interacts.

(17) A fastening element 21 is arranged at the second end of the second element 3, it being possible for this fastening element to be used to fasten the lifting column 1 on a piece of furniture, in particular on a table top. Furthermore, a flange is arranged in the region of the second end of the first element 2.

(18) FIG. 2 shows a perspective view of the lifting column according to FIG. 1, wherein the first wall 6 and the second wall 7 have been omitted for illustrative reasons. This illustration dearly 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 the linear guides. Also clear to see is the inclined arrangement of the rolling bodies 9.1, 9.2 of the rotor 8, said rolling bodies being designed in the form of cylindrical rollers and engaging in the thread helix 5 of the spindle 4.

(19) In contrast to the sectional illustration according to FIG. 1, the perspective view according to FIG. 2 shows the worm wheel 16 to better effect. The worm 17 is retained in a rotationally fixed manner relative to the second element 3 by a holder 22.

(20) FIG. 3 shows a perspective, detail-specific view of the second end of the second element 3. It clearly shows the worm 17, which is in engagement with the worm wheel 16. The worm wheel 17 has a hexagon-socket drive 25. Via this hexagon-socket drive 25, the worm 17 can be made to rotate by way of a hexagon key.

(21) The bevel wheel 11 is mounted in a rotatable manner in the cover 23 and is in engagement with the toothing formation 13 of the hollow shaft 12. The bevel wheel 11 has a central bore 26, by means of which the bevel wheel 17 can be brought into engagement with a shaft not shown).

(22) FIGS. 4a and 4b show detail-specific views of a second embodiment of a lifting column 1 according to the invention, in the case of which the rolling bodies 9.1-9.3 are designed in the form of bails. FIG. 4a shows a perspective view of the spindle 4, which has three thread helixes 5.1-5.3, in which a respective rolling body 9.1-9.3 designed in the form of a ball runs. The three rolling bodies 9.1-9.3 are arranged in each case at an angle of 120° in relation to one another, which can be seen to good effect in the sectional illustration of FIG. 4b. The thread helixes 5.1-5.3 of the spindle 4 have a round cross section, and therefore the rolling bodies 9.1-9.3, which are designed in the form of balls, can run therein with as little play as possible.

(23) FIGS. 5a and 5b show detail-specific views of a third embodiment of a lifting column 1 according to the invention, in the case of which the rolling bodies 9.1-9.3 are designed in the form of tapered rollers. FIG. 5a illustrates a perspective view of the spindle 4 with the rolling bodies 9.1-9.3, whereas FIG. 5b is a sectional illustration. These rolling bodies 9.1-9.3 run on the thread helixes 5.1-5.3 of the spindle 4, these thread helixes being in the form of areas on the surface of the spindle 4. Each of the rolling bodies 9.1-9.3 which are designed in the form of tapered rollers, has a pins 27.1-27.3, by way of which the rolling bodies 9.1-9.3 connected to the rotor 8.