EP3981287A1 - Raising column for furniture - Google Patents

Abstract

The present application relates to a lifting column for a piece of furniture, in particular for a table. The lifting column includes a first element and a second element. The second element is at least partially inserted into the first element. The first member has a spindle extending along the longitudinal axis of the first member and at least partially protruding into the second member. The second element has a rotatably mounted rotor in it, which has at least one roller which engages in a thread of the spindle. A rotation of the rotor relative to the spindle results in a linear movement of the second element relative to the first element. The second element also has a detent which, in a first state, blocks the rotation of the rotor relative to the spindle and in a second state releases the rotation of the rotor relative to the spindle. At least one torsion spring is clamped between the rotor and a fastening element, which is fastened to the second element, so that it exerts a prestressing force on the rotor.

Description

technical field

The present invention relates to a lifting column for a piece of furniture, in particular for a table, which has a compensation for the weight of the piece of furniture. Furthermore, the invention relates to a piece of furniture, in particular a table with at least one lifting column with compensation for the weight of the piece of furniture.

State of the art

Different lifting columns or height-adjustable legs for furniture, in particular for tables, are known in the prior art. The length of the lifting column or the leg can be adjusted by motor or manually. In the case of manual adjustment in particular, it is advantageous if the lifting column or the height-adjustable leg has means with which the weight of the piece of furniture, in particular the weight of a tabletop, can be compensated.

the U.S. 7,658,359 discloses, for example, table height adjustment devices. The table leg comprises a first, outer column element and a second, inner column element, a weight compensation device, a locking device and rollers which are arranged on the inner column element and which interact with raceways in the outer column element. The counterbalancing device includes, among other things, a spring, a worm wheel for compensating for the variable spring force and a cable which interacts with the worm wheel and is fastened to the inside of the outer column element. The pretension of a compression spring acting on the bearing of the rope can be adjusted by means of a spool that can be actuated with a button.

Presentation of the invention

The object of the invention is to create a lifting column that belongs to the technical field mentioned at the outset, which is of simple construction and has a weight force compensation.

The solution to the problem is defined by the features of claim 1. According to the invention, the lifting column includes a first element and a second element. The second element is at least partially inserted into the first element. The first member has a spindle extending along the longitudinal axis of the first member and at least partially protruding into the second member. The second element has a rotatably mounted rotor in it, which has at least one roller which engages in a thread of the spindle. A rotation of the rotor relative to the spindle results in a linear movement of the second element relative to the first element. The second element also has a detent which, in a first state, blocks the rotation of the rotor relative to the spindle and in a second state releases the rotation of the rotor relative to the spindle. At least one torsion spring is clamped between the rotor and a fastening element, which is fastened to the second element, so that it exerts a prestressing force on the rotor.

The weight of a piece of furniture connected to the lifting column can be at least partially compensated for by the prestressing force of the at least one torsion spring. The use of at least one torsion spring also simplifies the construction of the lifting column. In addition, the construction of the lifting column according to the invention requires very little maintenance.

In the present application, a lifting column is understood to mean a device which can be placed on a base, in particular on a floor, and connected to a piece of furniture, with the length of the device being variable for the purpose of adjusting the height of the piece of furniture.

The lifting column according to the invention is used in particular for a table. In this case, the lifting column is preferably connected to a tabletop. A table preferably has one, two or else four lifting columns according to the invention.

The first and the second element are designed as hollow bodies, with both elements having the same shape in cross section. So that the second element can be inserted into the first element, the latter has slightly smaller dimensions in cross section. Preferably, the dimensions of the cross-section of the first and second elements are chosen such that when the second element is inserted into the first element, there is a gap of a few millimeters between the elements, but in particular a gap of less than 1 cm. The second element is inserted concentrically in the first element, which means that the longitudinal axis of the first element coincides with the longitudinal axis of the second element.

The first and second elements preferably have a round, rectangular or polygonal shape in cross section. The first and the second element are preferably formed from a metal or from a metal alloy, in particular from stainless steel or from aluminium. The two elements are preferably elongate, which means that their length is considerably greater than their cross section. Preferably, the first and the second element each have a length of at least 35 cm, in particular at least 45 cm. Their maximum dimension in cross section is preferably 3 cm, more preferably 5 cm.

The first element preferably has a closed surface at a first end, with which the first element can be placed on a base, in particular on a floor. The first element is open at the second end opposite the first end, so that a first end of the second element can be inserted into this second end of the first element. At the second end of the second element opposite the first end, this preferably has means for fastening the second element to a piece of furniture. These means are preferably designed as holes or elongated holes for screws or bolts.

By moving the second element in and out of the first element, a length adjustment of the lifting column can be achieved. This length adjustment allows the height of a piece of furniture connected to the lifting column to be adjusted. Depending on the length setting of the lifting column, the second element will thus be inserted into the first element over a longer or shorter section of its length. The spindle is preferably centrally located in the first member and extends from the first end to the second end of the first member. The spindle thus extends along the longitudinal axis of the first element. The spindle can extend along the entire length of the first element, ie from its first end to its second end. However, the spindle preferably only extends over part of the length of the first element.

The spindle preferably has a high-helix thread. In the following application, the term “helix thread” means a thread with a pitch (pitch) of at least 10 mm, preferably at least 20 mm. The spindle preferably has a thread. Alternatively, however, the spindle can also have more than one thread, in particular two threads.

The rotor is preferably rotatably mounted in the second element via a roller bearing, so that the rotor can rotate relative to the second element. The rotor is oriented such that it can rotate about the longitudinal axis of the second element. The at least one roller of the rotor is preferably arranged at an angle which corresponds to the pitch angle of the spindle. The rotor preferably has more than one roller, in particular three rollers, which are each arranged at an angle of 120° to one another in the circumferential direction of the rotor.

A rotation of the rotor causes it to be linearly displaced relative to the spindle, since the at least one roller engages in the thread turn of the spindle. Since the rotor is rotatably mounted on the second element, a displacement of the rotor relative to the spindle also leads to a linear displacement of the second element relative to the first element.

If the lock blocks the rotation of the rotor, unintentional length adjustment of the lifting column can be prevented. When the lifting column is attached to a piece of furniture, the locking mechanism remains in the first state and is only switched to the second state when the piece of furniture is to be adjusted in height. For switching between the first state and the second state (and back), the Locking preferably via an actuating element, in particular via a lever or a button, which can be operated by a person.

The length of the lifting column according to the invention is preferably adjusted manually. This means that a person achieves a length adjustment by pulling or pushing the second element out of or into the first element. If a piece of furniture is connected to the lifting column, the length of the lifting column and ultimately the height of the piece of furniture can be adjusted by pulling the piece of furniture up or down. In the first state, the lock blocks the rotation of the rotor and thus also the length adjustment of the lifting column or the height adjustment of a piece of furniture connected to the lifting column.

Alternatively, however, the rotor can be set in rotation with an electrical or electromechanical drive, with which an automatic length adjustment of the lifting column or an automatic height adjustment of a piece of furniture connected to the lifting column can be achieved.

The fastening element is preferably firmly connected to the second element, which means that the fastening element cannot rotate about the longitudinal axis of the second element. A first leg of the at least one leg spring is connected to the fastening element or bears against it, while a second leg is non-rotatably connected to the rotor.

A torsion spring has two legs between which there are a large number of coils of the spring. The at least one torsion spring is preferably arranged within the second element in such a way that the longitudinal axis of the torsion spring coincides with the longitudinal axis of the second element.

Torque is exerted on the rotor by the prestressing force of the torsion spring. This torque rotates the rotor in one direction, provided that the rotor rotation is released by the detent. The torsion spring is arranged in such a way that the prestressing force exerts a torque on the rotor, which causes the second element to move out of the first element, ie leads to an extension of the lifting column. Here acts on the second element in the corresponding direction directed force. When the lifting column is used as intended, the first element stands on a base, in particular on a floor, with the longitudinal axis of the first and of the second element being perpendicular to the base. The longitudinal axes of the first and of the second element are accordingly aligned essentially parallel to the effective direction of gravity. The force acting on the second element is therefore directed essentially vertically upwards. As a result, this force counteracts the weight of a piece of furniture connected to the lifting column. As a result, the weight of the piece of furniture can be at least partially compensated, which in particular facilitates the extension of the lifting column or the raising of the piece of furniture. By appropriately adjusting the prestressing force of the torsion spring, the weight of a piece of furniture connected to the lifting column can also be fully compensated. In this case, the height of the piece of furniture is not adjusted without an external force, even if the locking device is in the second state, since the weight and the force acting on the second element cancel each other out.

In order to adjust the prestressing force of the at least one leg spring, the fastening element can preferably be moved in the shape of a circular arc around the longitudinal axis of the leg spring.

The prestressing force of the torsion spring, which corresponds to the spring force, can be adjusted by the circular movement of the fastening element. In this case, the fastening element has means with which the rotation of the fastening element can be blocked. As a result, a set preload force can be maintained. In particular, the means have a lever or handle that can be operated by one person. Furthermore, the second element preferably has adjusting means with which the fastening element can be set in motion in a circular manner about the longitudinal axis of the torsion spring.

The fastening element is preferably arranged on a worm wheel, which can be set into a rotational movement by means of a worm connected in a rotationally fixed manner to the second element.

This achieves a particularly simple embodiment of a fastening element that can be moved in a circular manner about the longitudinal axis of the torsion spring. In addition, due to the self-locking inherent in worm gears, additional means for blocking the circular movement of the fastening element about the longitudinal axis of the torsion spring can be dispensed with.

Preferably, the first element and the second element have a round cross-section, with the second element having a smaller diameter than the first element.

The second element is preferably guided in a linearly movable manner within the first element by at least one linear guide. The linear guide can prevent the second element from twisting within the first element. The second element is preferably guided by more than one linear guide within the first element, in particular by two, three or four linear guides. The linear guide can be designed, for example, as a pin running in a groove or as a roller guide.

The second element preferably has at least one roller bearing, with an outer ring of the roller bearing being inserted into a groove of the first element in order to form the at least one linear guide. As a result, a linear guide with a very low resistance can be implemented in a simple manner, which is also space-saving.

A ball bearing is preferably used as the roller bearing. Alternatively, however, a cylindrical roller bearing or a needle bearing can also be used. Preferably, the second element has a plurality of rolling bearings distributed around its circumference, which are inserted in a corresponding number of grooves of the first element.

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

In a further preferred embodiment, two of the three roller bearings are arranged at an angle of 90° relative to one another, these two roller bearings each being arranged at an angle of 135° to the third roller bearing around the longitudinal axis of the second element. In this embodiment, the first member preferably has 8 grooves each arranged at an angle of 45° relative to each other about the longitudinal axis of the first member. This allows the second element to be inserted into the first element in 8 different angular positions.

The rotor is preferably connected to a hollow shaft which extends within the second element coaxially thereto to a second end of the second element which is not inserted into the first element, the hollow shaft in the region of the second end of the second element having a interlocking.

In the first state, the locking device preferably engages in the toothing with a toothed rack fastened to the second element or with a gear wheel which is non-rotatably connected to the second element. As a result, the rotary shaft and thus also the rotor connected to it cannot rotate. In the second state, the rotation of the hollow shaft and the rotor can be released by lifting, pushing away or pivoting the toothed rack or the gearwheel away from the toothing.

Furthermore, the length adjustment of several lifting columns can be synchronized by means of the toothing, in that they are connected by means of at least one shaft, which engage in the toothing of the respective lifting columns with toothed or bevel gears.

The thread of the spindle preferably has a variable pitch. As a result, the spring force of the torsion spring, which varies depending on the insertion depth of the second element into the first element, can be compensated.

Movement of the second member relative to the first member rotates the rotor about the spindle. This means that the spiral spring is more or less tensioned depending on the position of the second element relative to the first element, which means that the spring force exerted on the rotor or the torque caused by this varies. By varying the pitch of the thread accordingly, the goal can be achieved in spite of this fact, namely that a constant force is generated by the torsion spring is exerted on the rotor and thus on the second element. In areas in which the torsion spring is less tensioned and therefore a lower spring force is exerted, the pitch of the thread is smaller than in areas in which the torsion spring has a higher tension and thus a higher spring force.

The at least one roller is preferably designed as a roller bearing, in which an outer ring engages in the thread of the spindle. This arrangement makes it possible to achieve a simple, low-maintenance configuration of the at least one roller, which also has a very low rolling resistance.

A ball bearing is preferably used as the roller bearing. Alternatively, however, a cylindrical roller bearing or a needle bearing can also be used. Preferably, the outer ring of the roller bearing has a bulge surrounding it, which is complementary to the profile of the thread. This achieves a particularly good engagement of the at least one roller in the thread of the spindle.

A plurality of torsion springs, in particular two torsion springs, are preferably clamped in parallel between the rotor and the fastening element. This means that all of these multiple torsion springs are fastened to the rotor with one leg, while the other leg rests on the fastening element or is connected to it.

With this arrangement, the force exerted on the rotor by the prestressing force generated by the torsion springs can be increased.

The present invention also relates to a piece of furniture with at least one lifting column described above and at least one furniture element which is attached to the at least one lifting column. The furniture is preferably a table, in which case the furniture element to which the at least one lifting column is attached is a table top.

The piece of furniture preferably has more than one lifting column, in particular two or four lifting columns. For example, the piece of furniture can be a height-adjustable desk that has two lifting columns that are attached to a rectangular tabletop.

A shaft is preferably attached to the furniture element, which has a bevel gear which engages in the toothing of the hollow shaft of the at least one lifting column.

This shaft can be used to synchronize the rotation of rotors from a number of lifting columns attached to the furniture element. The shaft preferably has a bevel gear at both ends, so that the rotation of rotors of two lifting columns attached to the furniture element can be synchronized by means of the shaft. If more than two lifting columns are attached to the furniture element, several shafts with two bevel gears are used accordingly.

The shaft is preferably attached to the furniture element by means of a holder, the holder having a double wrap spring brake which acts on the shaft. The double wrap spring brake acts as a detent, since it can block and release the rotation of the hollow shaft and thus of the rotor connected to it. The holder preferably has an actuating element, for example a lever, with which the braking effect of the double wrap-spring brake on the shaft can be released.

Further advantageous embodiments and combinations of features of the invention result from the following detailed description and the entirety of the patent claims.

Brief description of the drawings

Fig. 1

ein Schnittbild einer Ausführungsform einer erfindungsgemässen Hubsäule;

Fig. 2

die Hubsäule gemäss Fig. 1 in einer perspektivischen Sicht;

Fig. 3

eine Detailansicht des zweiten Endes des zweiten Elements.

The drawings used to explain the embodiment show:

1

a sectional view of an embodiment of a lifting column according to the invention;

2

the lifting column according to 1 in a perspective view;

3

a detailed view of the second end of the second element.

In principle, the same parts are provided with the same reference symbols in the figures.

Ways to carry out the invention

the 1 shows a sectional view of an embodiment of a lifting column 1 according to the invention. The lifting column 1 comprises a first element 2 which has a peripheral first wall 6 which encloses an interior space. A second element 3 with a second peripheral wall 7 is partially inserted into the first element 2, ie into the interior of the first element 2. A first end of the second element 3 is located inside the first element 2, while a second end of the second element 3, which is opposite to the first end, protrudes therefrom.

In the embodiment shown, both elements 2, 3 have a round 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 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 thereof. The second element 3 has the same longitudinal axis A as the first element 3.

The second element 3 is displaceably mounted in the first element 2 via linear guides. The linear guides have two grooves 19.1, 19.2 on the side of the first wall oriented towards the interior, in each of which an outer ring of roller bearings 18.1, 18.2, which are arranged at a first end of the second element 3, run. In the embodiment shown, the first element has eight grooves 19.1, 19.2, of which in FIG 1 only two are visible, which are offset by 45 ° to each other about the longitudinal axis A on the first wall 6 are distributed. Furthermore, the second element 3 has three roller bearings 18.1, 18.2, of which in the 1 only two are visible. The first roller bearing 18.1 and the second roller bearing 18.2 are at an angle of 135° to one another around the longitudinal axis A, while the third roller bearing, not visible here, is at an angle of 90° relative to the first roller bearing 18.1 and the second roller bearing 18.2.

The first element 2 also has a closed surface 24 at its first end. The first element 2 can be placed on a floor by means of this closed surface 24 . A spindle 4 is fastened centrally within the first element 2 to this closed surface 24 . The spindle 4 extends along the longitudinal axis A of the first element 2 not quite to its second end. This means that the spindle 4 does not protrude from the interior of the first element 2. The spindle 4 has a thread 5 with a variable pitch. The pitch of the thread 5 decreases from the first end of the spindle 4 to its second end.

A rotor 8 is arranged in the second element 3 in the region of its first end. The rotor 8 is rotatably mounted on the second element 3 so that it can rotate freely about the longitudinal axis A, but cannot be displaced relative to the second element 3 . Three rollers 9.1 are arranged on the rotor 8 (of which in 1 only one is visible), which engage in the thread 5 of the spindle 4. The rollers 9.1 are attached at an angle relative to the rotor 8, so that they can engage in the thread 5 essentially without play. A rotation of the rotor 8 causes the second element 3 to move linearly relative to the first element 2 via the engagement of the rollers 9.1 in the thread 5.

In the area of the second end, the second element 3 has two fastening elements 15.1, 15.2. Two torsion springs 14.1, 14.2 are clamped between the fastening elements 15.1, 15.2 and the rotor 8. The torsion springs 14.1, 14.2 are fixed against rotation with the rotor 8 and the respective fastening element 15.1, 15.2. The torsion springs 14.1, 14.2 exert a pretensioning force on the rotor 8. This biasing force generates a torque on the rotor 8 . The torsion springs 14.1, 14.2 are prestressed in such a way that the torque rotates the rotor 8 in the direction that generates a movement of the second element 3 from the first element 2. If the lifting column 1 stands on a floor, the prestressing force thus causes an extension of the lifting column 1. The weight of a piece of furniture fastened to the lifting column 1 can now be compensated for by the prestressing force. This means that the prestressing force is selected in such a way that it essentially corresponds to the weight of the piece of furniture connected to the lifting column 1 . This means that one person can adjust the height of the furniture relatively easily and without great effort.

The prestressing force that the torsion springs 14.1, 14.2 exert on the rotor 8 varies depending on the position of the rotor 8 along the spindle 4, since the torsion springs 14.1, 14.2 are twisted more or less out of their rest position by the rotation of the rotor 8. In order to keep the prestressing force acting from the rotor 8 on the second element 3 essentially constant in every position of the rotor 8 along the length of the spindle 4, the spindle 4 has the above-mentioned variable pitch of the thread pitch.

In the area of the second end of the second element 3, a worm wheel 16 is arranged, with which the fastening elements 15.1, 15.2 are connected. By turning a snail 15 (see 3 ) the worm wheel 16 can be turned. This rotation allows the prestressing force of the torsion springs 14.1, 14.2 to be varied, since the fastening elements 15.1, 15.2 are rotated at the same time.

The rotor 8 is connected to a hollow shaft 12 which extends in the direction of the second end of the second element 3 within the windings of the torsion springs 14.1, 14.2. In the area of the second end of the second element 3 , the hollow shaft 12 has teeth 13 . A bevel gear 11 engages in this toothing 13 . The bevel gear 11 and the toothing 13 together form a detent 10, with which the rotation of the rotor 8 relative to the spindle 4 is blocked in a first state and released in a second state. The rotation of the bevel gear 11 is blocked in the first state and released in the second state. This can be achieved by providing an appropriate mechanism. For example, the bevel gear 11 can be connected to a shaft (not shown) with which a double wrap spring brake interacts.

A fastening element 21 is arranged at the second end of the second element 3, with which the lifting column 1 can be fastened to a piece of furniture, in particular to a tabletop. A flange is also arranged in the area of the second end of the first element 2 .

the 2 shows the lifting column according to 1 in a perspective view with the first wall 6 and the second wall 7 omitted for illustrative purposes. The arrangement of the three roller 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, is clearly visible in this illustration. The inclined arrangement of the rollers 9.1, 9.2 of the rotor 8, which engage in the thread 5 of the spindle 4, is also clearly visible.

In contrast to the sectional view according to 1 is the worm wheel 16 in the perspective view according to 2 better to recognize. The worm 17 is held non-rotatably relative to the second element 3 by a holder 22 .

the 3 Figure 3 is a detailed view of the second end of the second element 3 in a perspective view. The worm 17, which is in engagement with the worm wheel 16, is clearly visible. The worm wheel 17 has a hexagon socket drive 25. This hexagon socket drive 25 can be used to rotate the worm 17 with a hexagon wrench.

The bevel gear 11 is rotatably mounted in the cover 23 and is in engagement with the teeth 13 of the hollow shaft 12 . The bevel gear 11 has a central bore 26 with which the bevel gear 17 can be brought into engagement with a shaft (not shown).

Claims (14)

Lifting column for a piece of furniture, in particular for a table, comprising a first element and a second element which is at least partially inserted into the first element, the first element having a spindle which extends along the longitudinal axis of the first element and at least partially protrudes into the second element, and wherein the second element has a rotatably mounted rotor in it, which has at least one roller which engages in a thread turn of the spindle, with a rotation of the rotor relative to the spindle causing a linear movement of the second element relative takes place to the first element, wherein the second element has a lock which blocks the rotation of the rotor relative to the spindle in a first state and releases the rotation of the rotor relative to the spindle in a second state, characterized in that between the rotor and a fastening element , which is attached to the second element, at least s a torsion spring is clamped so that it exerts a prestressing force on the rotor. Lifting column according to Claim 1, characterized in that in order to adjust the prestressing force of the at least one leg spring, the fastening element can be moved in the shape of a circular arc around the longitudinal axis of the leg spring. Lifting column according to Claim 2, characterized in that the fastening element is arranged on a worm wheel which can be set in rotary motion by means of a worm which is non-rotatably connected to the second element. Lifting column according to one of Claims 1 to 3, 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. Lifting column according to Claims 1 to 4, characterized in that the second element is guided in a linearly movable manner by at least one linear guide within the first element. Lifting column according to Claim 5, characterized in that the second element has at least one roller bearing, an outer ring of the roller bearing being inserted into a groove of the first element in order to form the at least one linear guide. Lifting column according to any one of claims 1 to 6, characterized in that the rotor is connected to a hollow shaft which extends inside the second element coaxially thereto towards a second end of the second element which is not inserted into the first element, wherein the hollow shaft has teeth in the region of the second end of the second element. Lifting column according to one of Claims 1 to 7, characterized in that the thread of the spindle has a variable pitch. Lifting column according to one of Claims 1 to 8, characterized in that the at least one roller is designed as a roller bearing, in which an outer ring engages in the thread of the spindle. Lifting column according to one of Claims 1 to 9, characterized in that a plurality of torsion springs, in particular two torsion springs, are clamped in parallel between the rotor and the fastening element. Furniture, in particular a table, with at least one lifting column according to one of Claims 1 to 9 and a furniture element, in particular a table top, to which the second element of the lifting column is attached. Furniture according to claim 11 and 7, characterized in that a shaft is attached to the furniture element, which has a bevel gear which engages in the toothing of the hollow shaft of the at least one lifting column. Furniture according to Claim 12, characterized in that the shaft is attached to the furniture element by means of a holder, the holder having a double coil spring brake which acts on the shaft. Furniture according to Claim 12 or 13 and 3, characterized in that a crankshaft is attached to the furniture element, with which the worm can be driven.

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