WO2022152510A1

WO2022152510A1 - Lifting mechanism for a height-adjustable table, height-adjustable table, and method for operating a lifting mechanism for a height-adjustable table

Info

Publication number: WO2022152510A1
Application number: PCT/EP2021/086649
Authority: WO
Inventors: Marcus Albert; Julian KLOTZ; Andreas Nonnenmacher
Original assignee: Kesseböhmer Holding Kg
Priority date: 2021-01-15
Filing date: 2021-12-17
Publication date: 2022-07-21
Also published as: DE102021200357B3

Abstract

The invention relates to a lifting mechanism (2) for a height-adjustable table (1), comprising: a drive motor (6); a linear mechanism (7) which can be connected to the drive motor (6) and is designed to convert a rotation produced by the drive motor (6) and introduced into the linear mechanism (7) into a converted linear movement, and to convert a linear movement introduced into the linear mechanism (7) into a converted rotation; and a brake device (5) which is separate from the linear mechanism (7) and is designed to brake the converted rotation.

Description

Lifting mechanism for a height-adjustable table, height-adjustable table and method for operating a lifting mechanism for a height-adjustable table

The invention relates to a lifting mechanism for a height-adjustable table, a height-adjustable table and a method for operating a lifting mechanism for a height-adjustable table, in particular for a height-adjustable table with a drive motor.

Height-adjustable tables are currently known, the height of which is adjusted, for example, by means of a gas spring, a grid mechanism or electrically. An electrical lifting mechanism is usually made up of a drive motor, a gear and a linear mechanism.

In order to prevent an unintentional adjustment of a tabletop of the height-adjustable table, a spindle gear with a moving spindle is used in the known electric lifting mechanisms, the self-locking of which is so great that the lifting mechanism cannot be moved by external influences on the tabletop. This is necessary to prevent, for example, the height of a height-adjustable table from changing in a de-energized state or from being changed in height due to an external load on the tabletop.

However, the self-locking acts in both directions of movement of the linear mechanism, ie both when the linear mechanism is extended and when it is retracted. Due to the self-locking, which is defined in such a way that the lifting mechanism cannot be moved by external influences on the table top, the efficiency of the movement spindle built into the electric lifting mechanism drops below 50% in both directions, which means that only a fraction of the available electrical energy can be converted into mechanical lifting work. However, the extension of the linear mechanism, i.e. an upward movement of the table top, always takes place under a load, so that no self-locking is required in this direction. Increased energy consumption caused by self-locking in this direction is converted into heat and thus wasted.

However, if a lifting mechanism with a self-locking mechanism that only works in one direction of movement is used, the problem arises that, for example, the tabletop can be raised by external influences, which means that some applications for the lifting mechanism, such as overhead installation of the Lifting mechanism, prevented, since the lifting mechanism would otherwise move by itself.

In addition, due to the relatively low efficiency of the moving spindle, it is necessary to design both the motor and the motor controller for higher performance, which results in increased manufacturing costs.

The object of the invention is to eliminate the problems mentioned above and to provide a lifting mechanism, a height-adjustable table and a method that provide safe operation of the height-adjustable table in the different applications and thereby optimize a drive power to be used.

The object is achieved by a lifting mechanism according to claim 1, a height-adjustable table according to claim 14 and a method according to claim 15. Advantageous further developments of the invention are contained in the dependent claims.

According to one aspect of the invention, a lifting mechanism for a height-adjustable table has a drive motor, a linear mechanism that can be connected to the drive motor and is designed to convert a rotary motion generated by the drive motor that is introduced into the linear mechanism into a converted linear movement, and a linear movement that is introduced into the linear mechanism to convert a converted rotary motion, and one from the linear mechanism separate braking device, which is designed to perform a braking of the converted rotary motion on.

Since the linear mechanism is designed both to convert the rotational movement that has been introduced into the converted linear movement and to convert the linear movement that has been introduced into the converted rotary movement, the linear mechanism does not have a self-locking effect. It is therefore possible to convert both rotary motion into linear motion and linear motion into rotary motion without causing an excessive braking effect. This makes it possible to improve the efficiency of the movement spindle and thus of the linear mechanism.

In order to ensure security against an unintentional adjustment of a tabletop of the height-adjustable table, a braking device separate from the linear mechanism is provided, which brakes the converted rotary movement resulting from the introduced linear movement.

In an advantageous embodiment of the lifting mechanism, the linear mechanism has a spindle mechanism with a threaded spindle, and a thread of the threaded spindle has a pitch that is defined in such a way that there is a spindle mechanism without self-locking.

A fixed pitch of the threaded spindle in connection with an associated spindle nut, so that there is a moving spindle without self-locking, is easy to produce without causing additional costs compared to a moving spindle with self-locking.

In a further advantageous embodiment of the lifting mechanism, the braking device has a housing, a drive shaft that can be connected to the drive motor, an output shaft that can be connected to the linear mechanism, a braking element with a through hole, at least one roller and a bearing device. In an assembled state of the braking device, the output shaft is designed to, by means of Bearing device to be rotatably mounted in the housing, the drive shaft and the output shaft are provided in alignment with one another in an axial direction, and the braking element is designed to be non-rotatable in the housing about an axis of the through hole arranged in alignment with the drive shaft and the output shaft, or by means of a predetermined torque to be rotated. The drive shaft is formed at least in a region of one end facing the output shaft as a hollow drive shaft with a tube wall and has in the region of the end facing the output shaft at least one inwardly directed elevation with a first driver contour and a recess penetrating the tube wall with a second driver contour on. The output shaft has at least one depression with a third driver contour on its circumference at one end facing the input shaft. The first driver contour and the third driver contour are designed to engage in one another with a predetermined play in the circumferential direction, and the second driver contour and the third driver contour are designed to accommodate the roller in such a way that the roller rotates when the third driver contour rotates relative to the second Driver contour moves in a radial direction. The second driver contour, the third driver contour and the roller are arranged in the axial direction in the through hole of the braking element in such a way that the braking device is designed so that, by rotating the third driver contour in a predetermined direction of rotation relative to the second driver contour, the braking or blocking is carried out by a non-positive connection between the braking element and the output shaft by jamming the roller between the through hole and the third driver contour, and that the roller is jammed by rotating the second driver contour in the predetermined direction of rotation relative to the third driver contour or is released by twisting the third driver contour against the predetermined direction of rotation to the second driver contour, the braking device being designed to transmit a torque from the drive shaft via the first driver contour and the third driver contour to the Ab to transmit the drive shaft when the jamming of the roller is released. This braking device can automatically brake the initiated linear movement, which has been converted into the converted rotary movement by the linear mechanism, in both directions.

The effect of the converted rotary motion via the output shaft is such that when the drive motor, and thus the drive shaft, is stationary, the third driver contour rotates in a predetermined direction of rotation relative to the second driver contour and the role between the braking element and the third driver contour of the output shaft is thereby increased gets stuck. This is done by abutting the roller in the circumferential direction against a wall of the penetrating recess of the second driver contour in the drive shaft, whereby, due to the indentation on the circumference of the output shaft, in this case a flat surface in the axial direction parallel to a tangent on the circumference, the roller rolls along the indentation during rotation and thus a distance between a point in the indentation at which the roller rests against the indentation and an inner wall of the through hole is reduced, so that the roller moves in the radial direction relative to the third driver contour or the second driver contour Moved direction and jamming occurs.

In order to enable the third driver contour to be rotated relative to the second driver contour, the first driver contour and the second driver contour engage with one another with the play predetermined in the circumferential direction. This means that the output shaft can move relative to the input shaft in an angular range of the predetermined play without the input shaft being moved as well.

The braking element is either non-rotatable or, in an alternative embodiment, rotatable by means of a predetermined torque about the axis of the through bore in the housing, which is aligned with the input shaft and the output shaft.

In a further advantageous embodiment of the lifting mechanism, the drive shaft has a plurality of inwardly directed elevations with the first driver contour and a plurality of recesses penetrating the tube wall with the second On driver contour, the output shaft has several recesses with the third driver contour and several roles are provided.

If several components are provided with the respective driver contours and several rollers, a greater braking torque can be generated without overloading the individual components provided and the individual roller.

In a further advantageous embodiment of the lifting mechanism, the braking device has a friction element and a preloading element, with the preloading element being arranged between the housing and the friction element, and the friction element being designed to be pressed against the braking element by means of the preloading element in such a way that a frictional force occurs between the friction element and the braking element in such a way that the braking element can be rotated by means of the predetermined torque.

The provision of the friction element and the pretensioning element makes it possible for the output shaft to be rotated by means of the predetermined torque when the roller jams between the braking element and the third driver contour and is not abruptly braked. Instead, even braking is possible without excessively stressing the components of the lifting mechanism and the table.

In a further advantageous embodiment of the lifting mechanism, the friction element is disk-shaped and is provided in the axial direction on a first side of the braking element so that it cannot rotate with respect to the housing, and another friction element is disk-shaped and is provided in the axial direction on a second side of the braking element , which is opposite to the first side with respect to the braking element, is provided non-rotatably with respect to the housing, the braking element is movable in the axial direction, and the prestressing element is designed to press the friction element against the braking element and the braking element against the further friction element by means of a prestressing force, so that the frictional force occurs. By providing two pairs of friction, namely between the first friction element and the braking element, and the braking element and the second friction element, the frictional force can be easily and precisely defined.

According to a further advantageous embodiment of the lifting mechanism, the braking element has an inner ring of a plain or roller bearing.

Such a braking element is easy and inexpensive to procure, with a rotatable radial bearing of the braking element being provided automatically, so that the production costs are further reduced.

In another advantageous embodiment of the lifting mechanism, the braking element has a ring with the through hole, the friction element is designed to be pressed against the ring, and the pretensioning element and the friction element are arranged radially to the braking element between the braking element and the housing.

With such an arrangement, the braking element can be supported radially by the pretensioning element and the friction element in order to press against the ring from the outside and to brake or block the ring. The provision of a further radial bearing of the braking element is thus unnecessary, the production costs can be reduced and a shorter length of the braking device in the axial direction can be achieved.

In a further advantageous embodiment of the lifting mechanism, an elastic element is provided which is designed to urge the roller or rollers radially outwards against the inner wall of the through hole.

By providing the elastic element, a defined position of the roller or rollers resting against the inner wall of the bore can be ensured, so that the jamming function is ensured and noise development due to existing play is prevented. According to a further advantageous embodiment of the lifting mechanism, the elastic element has an elastic O-ring.

The O-ring is easy and inexpensive to obtain and its position can be easily ensured by a dedicated circumferential groove in the output shaft.

According to another advantageous embodiment of the lifting mechanism, the braking device has an armature disk that protrudes radially from a shaft connected to the linear mechanism, so that the armature disk can be rotated with the shaft, and also has a stationary electric holding magnet that is designed to operate without a power supply To generate magnetic force on the armature disk so that the armature disk is held by the electro-holding magnet to perform braking, and with the power supply to cancel the magnetic force and braking.

The braking device is connected to the linear device either directly or indirectly, for example via an interposed transmission.

Due to the magnetic force from the stationary electro-holding magnet on the armature disk, the armature disk is held by the electro-holding magnet and thus the shaft is prevented from rotating. Due to the principle of the electro-holding magnet, this magnetic force is present when the electro-holding magnet is not supplied with energy, so that, for example with a corresponding electrical coupling of the drive motor and the electro-holding magnet, a common supply of the drive motor and the electro - holding magnets or in the event of a power failure, it is automatically ensured that the shaft can no longer rotate or is braked.

In a further advantageous embodiment of the lifting mechanism, several armature disks are provided at an identical axial position of the shaft. The provision of several armature disks at an identical axial position enables a braking effect in a finer angular grid, so that a more precise position of the braked table top is possible.

In another advantageous embodiment of the lifting mechanism, the braking device has a friction disk that protrudes radially from a shaft connected to the linear mechanism, so that the friction disk can be rotated with the shaft. Furthermore, the braking device has a stationary actuator unit with an elastic element, a pressure element that can be pressed onto the friction disc in a pretensioning direction by means of the elastic element, an electromagnet which is designed to apply a release force to the pressure element in a release direction opposite to that when the electromagnet is supplied with energy Apply bias direction, and without power supply, no release force to exert on the pressure element.

Due to the pressure of the pressure element on the friction disk caused by the elastic element, the friction disk, and thus the shaft, is braked when the electromagnet is not supplied with energy. For example, when a common supply of the drive motor and the electromagnet is switched off or in the event of a power failure, this automatically ensures that the shaft is braked by the pressure element and the friction disk and can no longer rotate any further.

According to another aspect of the invention, a height-adjustable table has a lifting mechanism, a tabletop that is connected to the lifting mechanism, and a guide element that can be set up on a floor and that guides a movement of the tabletop (3) relative to the floor.

With this height-adjustable table, both rotary motion can be converted into linear motion and linear motion can be converted into rotary motion without excessive braking effect. This makes it possible to improve the efficiency of the threaded spindle and thus of the linear mechanism. In order to ensure security against an unintentional adjustment of the table top of the height-adjustable table, a braking device separate from the linear mechanism is provided, which brakes the converted rotary movement resulting from the introduced linear movement.

According to a further advantageous aspect of the invention, a method for operating a lifting mechanism has the following steps: introduction of a force by means of an introduced linear movement in the linear mechanism, conversion of the introduced force by the linear mechanism into a converted torque in the direction of a converted rotary movement, and application of a Counter-torque to the converted torque by the braking device separate from the linear mechanism, so that the converted rotational movement is braked.

This method makes it possible to convert rotary motion into linear motion as well as linear motion into rotary motion without causing an excessive braking effect. This makes it possible to improve the efficiency of the movement spindle and thus of the linear mechanism.

In an advantageous embodiment of the method, the converted rotational movement causes the output shaft to rotate in relation to the input shaft, with the roller becoming jammed between the inner wall of the through hole and the third driver contour as a result of the third driver contour being rotated in the predetermined direction of rotation relative to the second driver contour, so that the Counter-torque is applied, and the jamming is solved by twisting the second driver contour in the predetermined direction of rotation to the third driver contour or by twisting the third driver contour against the predetermined direction of rotation to the second driver contour. As a result of this method step, the linear movement that has been introduced and converted into the converted rotary movement by the linear mechanism can be braked and released automatically.

In another advantageous embodiment of the method, the counter-torque is generated by a magnetic force of the electro-holding magnet on the armature disk due to a lack of energy supply to the stationary electro-holding magnet.

In the case of the stationary electro-holding magnet, this magnetic force is present when the electro-holding magnet is not being supplied with energy, so that it is automatically ensured, for example when a common supply of the drive motor and the electro-holding magnet is switched off or in the event of a power failure, that the counter-torque is produced. In a further advantageous embodiment of the method, the counter-torque is generated by the pressure element pressed by the elastic element in the pretensioning direction onto the friction disc due to the lack of the release force due to the lack of energy supply to the electromagnet.

By the pressure of the pressure element caused by the elastic element on the friction disc, the friction disc, and thus the shaft, is braked when the electromagnet is not supplied with energy, so that, for example when a common supply of the drive motor and the electromagnet is switched off or when a Power failure automatically ensures that the shaft can no longer rotate.

The invention is explained below with the aid of embodiments with reference to the accompanying drawings.

In particular shows

1 shows a schematic representation of a side view of a height-adjustable table; 2 shows a sectional representation of a braking device according to a first embodiment and a schematic representation of a drive motor and a linear mechanism;

FIG. 3 shows an exploded view of the braking device according to FIG. 2;

4a shows a situation in which the braking device according to the first embodiment is in a “zero position”;

4b shows a first and third driver contour of the braking device according to the first embodiment in the situation according to FIG. 4a;

5a shows a situation in which the braking device according to the first embodiment is in a situation in which the output shaft is braked;

FIG. 5b shows the first and third driver contour of the braking device according to the first embodiment in the situation according to FIG. 5a;

6a shows a situation in which the braking device according to the first embodiment is in a situation in which braking is just being released;

FIG. 6b shows the first and third carrier contour of the braking device according to the first embodiment in the situation according to FIG. 6a;

7a shows a situation in which the braking device according to the first embodiment is in a situation in which the braking is released;

FIG. 7b shows the first and third carrier contour of the braking device according to the first embodiment in the situation according to FIG. 7a; 8 shows an exploded view of a braking device according to a second embodiment; and

9 shows a representation of a braking device according to a third embodiment.

1 shows a schematic representation of a side view of a height-adjustable table 1 . The height-adjustable table 1 has a lifting mechanism 2 for the height-adjustable table 1 and a table top 3 which is connected to the lifting mechanism 2 .

The table 1 also has two lifting columns 4 as a guide element, in each of which one of the lifting mechanisms 2 is arranged.

In alternative embodiments, depending on the application, a different number of lifting mechanisms 2, either only one lifting mechanism 2 or more than two lifting mechanisms 2, is provided and/or a guide element other than lifting columns, for example a linear guide with a guide of a fixed length, is provided.

Fig. 2 shows a sectional view of a braking device 5 according to a first embodiment and a schematic representation of a drive motor 6 and a linear mechanism 7. The lifting mechanism 2 of the height-adjustable table 1 has the drive motor 6, the linear mechanism 7 that can be connected to the drive motor 6 and the linear mechanism 7 separate braking device 5 on.

The drive motor 6 is connected to the linear mechanism 7 via the braking device 5 . In alternative embodiments, the drive motor 6 is connected directly to the linear mechanism 7 and the separate braking device 5 acts on a motor shaft 8 of the drive motor 6.

The drive motor 6 is an electric drive motor and is intended to generate a rotational movement with a predetermined torque. In alternatives Embodiments, the drive motor 6 can also be formed, for example, by a pneumatic drive motor.

The linear mechanism 7 has a spindle gear which has a threaded spindle 9 and a spindle nut 10 . A thread of the threaded spindle 9 has a pitch that is set so that the spindle thread forms a spindle gear without self-locking. This means that the linear mechanism 7 converts both the rotary movement generated by the drive motor 6 into a converted linear movement and also converts a linear movement introduced into the linear mechanism into a converted rotary movement. In contrast, a linear mechanism that has self-locking is able to convert the rotational movement introduced into the linear mechanism into a converted linear movement, but due to the self-locking, the linear mechanism cannot convert the linear movement introduced into the converted rotational movement.

In an alternative embodiment, the linear mechanism 7 is not designed as a spindle gear but, for example, as a worm gear with a pinion and a toothed rack, with the linear mechanism 7, in particular the worm gear, not having any self-locking here either.

The braking device 5 brakes the converted rotational movement. This means that the braking device 5 brakes the linear movement introduced into the linear mechanism 7, which is caused, for example, by placing the additional mass on the table top 3 and is converted by the linear mechanism 7 into the converted rotary movement.

Fig. 3 shows an exploded view of the braking device 5 according to the first embodiment of the braking device 5 shown in Fig. 2.

The braking device 5 according to the first embodiment has a housing 11 , a drive shaft 12 which can be connected to the drive motor 6 and an output shaft 13 which can be connected to the linear mechanism 7 . Furthermore, the braking device 5 a braking element 14 with a through hole 15, three rollers 16 and a storage device 17 on.

In an assembled state of the braking device 5 shown in FIG. 2 , the output shaft 13 is rotatably mounted in the housing 11 by means of the bearing device 17 . Further, the input shaft 12 and the output shaft 13 are provided in alignment with each other in an axial direction. The braking element 14 can be rotated in the housing 11 about an axis 18 of the drive shaft 12 and the output shaft 13 by means of a predetermined torque.

In order to set the predetermined torque, the braking device 5 has a friction element 19 and a further friction element 20 . The friction member 19 is formed in a disc shape and is provided in the axial direction on a first side of the brake member 14 non-rotatably to the housing 11 . For this purpose, the friction element 19, as shown in FIG. The further friction element 20 is also formed in a disk shape and is provided in the axial direction on a second side of the braking element 14 so as to be non-rotatable with respect to the housing 11 . For this purpose, the further rotary element 20 has a contour on the circumference that enables a positive connection with the housing 11 . The braking member 14 is movable in the axial direction, and further three compression springs are provided as biasing members 21 to press the friction member 19 to the braking member 14 by means of a biasing force and to press the braking member 14 to the other friction member 20 so that a friction force occurs and the predetermined torque can be adjusted.

In alternative embodiments, the further friction element 20 is not provided, but only the friction element 19 is used, in which case the braking element 14 is not movable in the axial direction and the frictional force occurs only between the friction element 19 and the braking element 14 . Furthermore, as an alternative, not three compression springs are provided as the pretensioning elements 21, but a different number is provided, with at least one pretensioning element 21 having to be provided, which, however, is not necessarily designed as a compression spring. In further alternative embodiments, the braking element 14 is formed as an inner ring of a sliding or roller bearing, or the braking element 14 is formed as a ring, and the pretensioning element and the friction element are arranged radially to the braking element 14 between the braking element 14 and the housing 11. In another alternative embodiment, none of the friction elements 19, 20 is provided, but the braking element 14 is provided in the housing 11 in a non-rotatable manner, for example via a form fit.

The drive shaft 12 is formed as a hollow drive shaft with a tubular wall 22 in a region of one end facing the output shaft 13 and has three inwardly directed elevations (Ref. 25; Fig. 4b, 5b, 6b, 7b), explained later, with a first driver contour on. Furthermore, in the region of the end 3 facing the output shaft 13 , the drive shaft 12 has recesses 23 penetrating the tube wall 22 with a second driver contour. The output shaft 13 has at least one recess 24 with a third driver contour on one end facing the drive shaft 12 on its circumference.

In this embodiment, the recess 23 with the second driver contour is arranged in such a way that it is open towards the end of the drive shaft 12 . Furthermore, the depression 24 with the third driver contour is designed as a flat surface in the axial direction parallel to a tangent on the circumference of the output shaft 13 . In alternative embodiments, the recess 23 with the second driver contour is arranged in the drive shaft 12 in the region of the end facing the output shaft 13 , but the recess 23 is not open at the end of the drive shaft 12 . Furthermore, in alternative embodiments, the indentation 24 with the third driver contour is not designed as a flat surface parallel to a tangent on the circumference of the output shaft 13, but has a suitable curvature. In addition, three inwardly directed elevations (Ref. 25; Fig. 4b, 5b, 6b, 7b) with the first driver contour, three recesses 23 penetrating the tube wall 22 with the second driver contour and three depressions 24 with the third driver contour are alternatively not provided , but a different number, each with at least one inside directed increase (Bzz. 25; Fig. 4b, 5b, 6b, 7b), a recess 23 and a recess 24 must be provided.

The second driver contour of the recesses 23, the third driver contour of the depressions 24 and the roller 16 are arranged in the axial direction in the through hole 15 of the braking element 14.

Furthermore, the braking device 5 has an elastic O-ring as an elastic element 26 . The elastic element 26 presses the rollers 16 radially outwards against an inner wall of the through hole 15. In alternative embodiments, the elastic element 26 is formed by another element, for example a spring washer made of steel, or no elastic element is provided.

4a and 4b show a situation in which the braking device 5 according to the first embodiment is in a so-called “zero position”.

Fig. 4a shows a partial section of the braking device 5 viewed in the direction of the axis 18 and Fig. 4b shows the first driver contour of the elevation 25 of the drive shaft 12 and the third driver contour of the depression 24 of the output shaft 13 of the braking device 5 in the situation according to Fig. 4a, It can be seen here that the output shaft 13 can rotate relative to the input shaft 12 without the input shaft 12 also rotating. The drive shaft 12 with the second driver contour of the recess 23 and the output shaft 13 with the third driver contour of the recess 24 are in the so-called “zero position”, in which the output shaft 13 is not braked. This means that there is at least a small gap between the roller 16 and the inner wall of the through hole 15 and the recess 24, so that the roller 16 is not jammed between the inner wall of the through hole 15 and the recess 24, and the output shaft 13 opposite the brake element 14 is rotatable. Fig. 4b shows the first driver contour of the elevation 25 of the drive shaft 12 and the third driver contour of the depression 24 of the output shaft 13 of the braking device 5 in the situation according to FIG it can be seen that the output shaft 13 can rotate relative to the input shaft 12 without the input shaft 12 also rotating.

The ridge 25 is shown as having a triangular cross-section with flat faces. In alternative embodiments, the cross section is not necessarily triangular and has flat surfaces, but is convex, for example.

Fig. 5a and Fig. 5b show a situation in which the braking device 5 is in a situation in which the output shaft 13 is being braked.

5a and 5b differ from FIGS. 4a and 4b in that the output shaft 13 has rotated counterclockwise by 10° relative to the braking element 14 . Since the second cam contour of the recess 23, the third cam contour of the recess 24 and the roller 16 are arranged in the axial direction in the through hole 15 of the brake member 14, and the roller 16 is pushed radially outward due to the elastic member 26, it rolls slightly along the inner wall of the through bore 15 and is then clamped between the inner wall of the through bore 15 and the depression 24 with the third driver contour, as a result of which the output shaft 13 is braked in relation to the braking element 14 and thus in relation to the housing 11. In this state, the drive shaft 12 has rotated counterclockwise by 4°. The drive shaft 12 is twisted by the elevation 25 with the first driver contour resting against the depression 25 with the third driver contour. This twisting is possible because the drive shaft 12 is not braked by the drive motor 6 .

The second driver contour and the third driver contour are thus designed to accommodate the roller 16 in such a way that the roller 16 moves in a radial direction when the third driver contour rotates relative to the second driver contour. By twisting the third driver contour in a predetermined direction of rotation to the second driver contour, counterclockwise in the figures, braking is achieved by a non-positive connection between the braking element 14 and the output shaft 13 by jamming the Roller 16 performed between the through hole 15 and the third driver contour.

Figures 6a and 6b differ from Figures 5a and 5b in that they show a situation in which the braking device 5 is in a situation in which braking is about to be released.

As shown in FIGS. 5a and 5b, the output shaft 13 is in the braked situation due to the anti-clockwise rotation by 10°, since the roller 16 is jammed. The drive shaft 12 was rotated in the transition from the situation in Fig. 5a and Fig. 5b to the situation in Fig. 6a and Fig. 6b by the drive motor 6 counterclockwise so that with a rotation of 9 ° of the drive shaft 12 relative to the "Zero position" the roller 16 rests against a wall of the recess 23. As can be seen in FIG. 6b, the output shaft 13 is not rotated via the first driver contour of the elevation 25 of the drive shaft 12 and the third driver contour of the recess 24 of the output shaft 13.

Figures 7a and 7b differ from Figures 6a and 6b in that they show a situation in which the braking of the braking device according to the first embodiment is released.

As already shown in FIGS. 5a, 5b, 6a, 6b, the output shaft 13 is still rotated counterclockwise by 10°. However, compared to the situation of Fig. 6a and Fig. 6b, the drive shaft 12 was rotated counterclockwise by a further 7° to 16°, so that the wall of the recess 23 moves the roller 16 in the counterclockwise direction and thus jamming the roller 16 solves.

If the counterclockwise rotation of the output shaft 13 shown in Fig. 5a and Fig. 5b is caused by the converted rotary movement from the introduced linear movement, which is caused by moving the table top 3 downwards, the 6b, 7a, 7b carried out a further movement of the table top 3 down. If the table top 3 is to be moved upwards from the situation shown in Fig. 5a and Fig. 5b, the drive shaft 12 is moved in a clockwise direction, so that the jamming of the roller 16 is released and the output shaft 13 via the first driver contour and the third driver contour is moved clockwise by the drive shaft 12 .

The jamming of roller 16 is thus released by rotating the second driver contour of recess 23 in the predetermined direction of rotation relative to the third driver contour of recess 24 or by rotating the third driver contour of recess 24 counter to the predetermined direction of rotation relative to the second driver contour of recess 23.

In comparison to the positions of the drive shaft 12 relative to the output shaft 13 shown in FIGS. 4°) can be rotated without the output shaft 13 also rotating. For this purpose, the first driver contour of the drive shaft 12 and the third driver contour of the output shaft 13 are designed to engage in one another with a play that is predetermined in the circumferential direction.

The angles and directions of rotation only serve to explain the function and can change in the braking device according to the first embodiment due to elasticity or tolerances of the components of the components. In alternative embodiments, other predetermined angles are possible.

FIG. 8 shows an exploded view of a braking device 5 according to a second embodiment.

The braking device 5 according to the second embodiment has a shaft 30 which is connected to the linear mechanism 7 . Two armature disks 31 protruding radially from the shaft 30 are attached to the shaft 30 at an identical axial position of the shaft 30 so that the armature disks 31 are rotatable with the shaft 30 . The braking device 5 has a housing 33, which is only shown in principle. The shaft 30 is mounted in the housing 33 via a bearing element 34 .

Furthermore, this braking device 5 has a stationary electric holding magnet 32, which generates a magnetic field without a power supply. When the shaft 30 with the armature disks 31 is in a corresponding position, the electro-holding magnet 32 generates a magnetic force on the armature disks 31 in such a way that a respective armature disk 31 is held in place by the electro-holding magnet 32 . As a result, the shaft 30 and thus the rotational movement converted by the linear mechanism 7 are braked.

When the electric holding magnet 32 is supplied with the appropriate energy, the magnetic field is disturbed or eliminated and the magnetic force on the armature disk 31 is eliminated.

The electric holding magnet 32 is mounted in the housing 33 in the lifting column 4 in such a way that it cannot rotate with the shaft 30 . In alternative embodiments, the electric holding magnet is not mounted in the lifting column 4, a separate housing 33 is not provided and/or a number other than two anchor plates 31 is provided and/or several electric holding magnets 32 are provided.

FIG. 9 shows a representation of a braking device 5 according to a third embodiment.

The third embodiment of the braking device 5 has a shaft 40 which is connected to the linear mechanism 7 . A friction disc 41 protruding radially from the shaft 40 is attached to the shaft 40 such that the friction disc 41 is rotatable with the shaft 40 .

Furthermore, this braking device 5 has two stationary actuator units 42 . Each stationary actuator unit 42 has an elastic element 43 and a pressure element 44 and an electromagnet 45 . In alternative embodiments, there is a different number of actuator units 42, either just one or more than two Actuator units 42 are provided. In a further alternative embodiment only one actuator unit 42 is provided and the actuator unit 42 and the pressure element 44 are aligned concentrically to the shaft 40 .

The elastic member 43 presses the pressing member 44 on the friction disk 41 in a biasing direction to thereby generate a frictional force between the stationary actuator unit 42 and the friction disk 41 so that the friction disk 41 is held by the actuator unit 42 via the pressing member 44 . As a result, the shaft 40 and thus the rotational movement converted by the linear mechanism 7 are braked.

The electromagnet 45 is designed to apply a release force to the pressure element 44 counter to the pretensioning direction when the electromagnet 45 is supplied with energy. The pressure element 44 is lifted off the friction disk 41 by this release force and the frictional force is eliminated so that the shaft 40 is no longer braked.

Without an energy supply, the electromagnet 45 does not exert any release force on the pressure element 44, so that the pressure element 44 is pressed against the friction disc 41 by the elastic element 43 and the shaft 40 brakes.

The actuator unit 42 is mounted in the lifting column 4 in such a way that it cannot rotate with the shaft 40 . In alternative embodiments, the actuator unit 42 is not mounted in the lifting column 4 .

The shaft 30 and the shaft 40 in the second and third exemplary embodiment are each separate shafts of the braking device 5 which are connected or can be connected to the linear mechanism 7 and the drive motor 6 . In alternative embodiments, either a common shaft of the drive motor 6, the braking device 5 and the linear mechanism 7 is provided, or the shaft 30 and/or the shaft 40 are provided either integrally with the shaft of the drive motor 6 or the shaft of the linear mechanism 7. Furthermore, the braking device 5 alternatively arranged within a motor housing or on an opposite side of the linear mechanism 7 with respect to the drive motor 6 .

In addition, in further alternative embodiments, a gear is provided in order to convert a speed and a torque of the drive motor 6 in such a way that they are suitable for the linear mechanism 7 . The braking device 5 is then provided either between the drive motor 6 and the gear or between the gear and the linear mechanism 7 . As already mentioned above, the braking device 5 according to the second and third embodiment can also be integrated into the drive motor 6 or can be provided on an opposite side of the linear mechanism 7 with respect to the drive motor 6 .

In operation, a method for operating the lifting mechanism 2 is carried out with the following steps. In the first step, a force is introduced into the linear mechanism 7 in the direction or in the opposite direction to the converted linear movement. This force is caused either only by the weight of the table top 3, or by placing an additional mass on the table top 3, supporting a person on the table top 3 or lifting the table top 3.

In the next step, the force introduced is converted by the linear mechanism 7 into a converted torque in the direction of the converted rotational movement.

In a further step, a counter-torque to the converted torque is applied by the braking device 5, which is separate from the linear mechanism 7, so that the converted rotational movement is braked. Depending on the embodiment of the braking device 5, the counter-torque is applied by the jamming of the roller 16 between the braking element 14 and the depression 24 of the output shaft 13, by the magnetic force of the electro-holding magnet 32 on the armature disks 31 or by the frictional force of the pressure element 44 the friction disk 41 generates. In the case of the braking device 5 according to the first embodiment, the converted torque causes the output shaft 13 to rotate relative to the drive shaft 12 and the roller 16 is jammed by the rotation of the third driver contour in the predetermined direction of rotation relative to the second driver contour between the through bore 15 of the braking element 14 and the third driver contour so that the counter-torque is applied.

By twisting the second driver contour in the predetermined direction of rotation to the third driver contour or by twisting the third driver contour against the predetermined direction of rotation to the second driver contour, the jamming is released, so that subsequent rotation of the output shaft 13 is possible.

In the case of the braking device 5 according to the second embodiment, the counter-torque is generated by a magnetic force of the electro-holding magnet on the armature disk 31 when there is no energy supply to the stationary electro-holding magnet 32 .

In the case of the braking device 5 according to the third embodiment, the counter-torque is generated by the pressure element 44 pressed by the elastic element 43 in the pretensioning direction on the friction disk 41 when the release force is absent due to the lack of power supply to the electromagnet 45 .

All of the features presented in the description, the following claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims

25 patent claims

1 . Lifting mechanism (2) for a height-adjustable table (1), with a drive motor (6), a linear mechanism (7) which can be connected to the drive motor (6) and is designed to transmit a force generated by the drive motor (6) into the linear mechanism (7 ) to convert a rotary movement introduced into a converted linear movement and to convert a linear movement introduced into the linear mechanism (7) into a converted rotary movement, and a braking device (5) which is separate from the linear mechanism (7) and is designed to brake the converted rotary movement.

2. lifting mechanism (2) according to claim 1, wherein the linear mechanism (7) has a spindle gear with a threaded spindle, and a thread of the threaded spindle has a pitch that is set so that there is a spindle gear without self-locking.

3. Lifting mechanism (2) according to claim 1 or 2, wherein the braking device (5) has: a housing, a drive shaft (12) which can be connected to the drive motor (6), an output shaft (13) which is connected to the linear mechanism ( 7) can be connected, a braking element (14) with a through hole (15), at least one roller (16), and a bearing device (17), wherein, in an assembled state of the braking device (5), the output shaft (13) is designed for this purpose is, by means of the storage device

(17) to be rotatably supported in the housing (11), the input shaft (12) and the output shaft@13) are provided in alignment with each other in an axial direction, the braking element (14) is designed to be in the housing (11). an axis (18) aligned with the input shaft (12) and the output shaft (13). arranged through hole (15) to be non-rotatable or to be rotatable by means of a predetermined torque, the drive shaft (12) is formed as a hollow drive shaft with a tubular wall (22) at least in a region of one end facing the output shaft (13), the drive shaft bracket 12) in the area of the end facing the output shaft (13) has at least one inwardly directed elevation (25) with a first driver contour, the drive shaft (12) in the area of the end facing the output shaft (13) has at least one ridge penetrating the tube wall (22). has a recess (23) with a second driver contour, the output shaft (13) has at least one depression (24) with a third driver contour on its circumference at one end facing the drive shaft (12), the first driver contour and the third driver contour are designed for this purpose, engage with one another with a predetermined play in the circumferential direction, and the second driver con ture and the third driver contour are designed to receive the roller (16) in such a way that the roller (16) moves in a radial direction when the third driver contour rotates relative to the second driver contour, with the second driver contour, the third driver contour and the Roller (16) are arranged in the axial direction in the through hole (15) of the braking element (14) in such a way that the braking device (5) is designed such that, by rotating the third driver contour in a predetermined direction of rotation relative to the second driver contour, the braking is carried out by a non-positive connection between the braking element (14) and the output shaft (13) by jamming the roller (16) between an inner wall of the through hole (15) and the third driver contour, and that the jamming of the roller (16) by twisting the second driver contour in the predetermined direction of rotation relative to the third driver contour or by twisting en the third driver contour is released counter to the predetermined direction of rotation to the second driver contour, and wherein the braking device (5) is designed to transmit a torque from the drive shaft (12) via the first driver contour and the third driver contour to the output shaft (13) when the jamming of the roller (16) is released.

4. Lifting mechanism (2) according to claim 3, wherein the drive shaft (12) has several inwardly directed elevations (25) with the first driver contour and several recesses (23) penetrating the tube wall (22) with the second driver contour, the output shaft (13 ) has a plurality of depressions (24) with the third driver contour and a plurality of rollers (16) are provided.

5. lifting mechanism (2) according to claim 3 or 4, wherein the braking device (5) has a friction element (19) and a biasing element (21), wherein the biasing element (21) between the housing (11) and the friction element (19) is arranged and the friction element (19) is designed to be pressed against the braking element (14) by means of the pretensioning element (21) in such a way that a frictional force occurs between the friction element (19) and the braking element (14) in such a way that the braking element (14) can be rotated by means of the predetermined torque.

6. lifting mechanism (2) according to claim 5, wherein the friction element (19) is disc-shaped and is provided in the axial direction on a first side of the braking element (14) non-rotatably to the housing (11), another friction element (20) , which is formed in a disk shape and is provided in the axial direction on a second side of the brake member (14) opposite to the first side with respect to the brake member (14), non-rotatably to the housing (11), the brake member (14) in the is movable in the axial direction, and the prestressing element (21) is designed to press the friction element (19) against the braking element (14) and the braking element (14) against the further friction element (20) by means of a prestressing force, so that the frictional force occurs . 28

7. lifting mechanism (2) according to claim 5 or 6, wherein the braking element (14) has an inner ring of a plain or roller bearing.

8. lifting mechanism (2) according to claim 5, wherein the braking element (14) has a ring with the through hole (15), the friction element (19) is designed to be pressed against the ring, and the biasing element (21) and the Friction element (19) are arranged radially to the braking element (14) between the braking element (14) and the housing (11).

9. Lifting mechanism (2) according to one of Claims 3 to 8, in which an elastic element (26) is provided which is designed to press the roller (16) or rollers (16) radially outwards against the inner wall of the through hole (15 ) to urge.

10. lifting mechanism (2) according to claim 9, wherein the elastic element (26) comprises an elastic O-ring.

11 . Lifting mechanism according to claim 1 or 2, wherein the braking device (5) comprises: an armature disk (31) projecting radially from a shaft (30) connected to the linear mechanism (7) so that the armature disk (31) can rotate with the shaft (30). and a stationary electric holding magnet (32), which is designed to generate a magnetic force on the armature disk (31) without a power supply in such a way that the armature disc (31) is held in place by the electric holding magnet (32) in order to Perform braking, and cancel the magnetic force and braking with the power supply.

12. lifting mechanism (2) according to claim 11, wherein 29 a plurality of armature disks (31) are provided at an identical axial position of the shaft.

13. Lifting mechanism (2) according to claim 1 or 2, wherein the braking device (5) comprises: a radially connected to the linear mechanism (7) shaft (40) protruding friction disc (41), so that the friction disc (41) with the Shaft (40) is rotatable, a stationary actuator unit (42) with an elastic element (43), a pressure element (44) which can be pressed onto the friction disk (41) in a pretensioning direction by means of the elastic element (43), an electromagnet (45), which is designed to apply a release force to the pressure element (44) in a release direction opposite to the pretensioning direction when the electromagnet (45) is supplied with energy, and not to exert any release force on the pressure element (44) without the energy supply.

14. Height-adjustable table (1) with a lifting mechanism (2) according to one of the preceding claims, a table top (3) which is connected to the lifting mechanism (2), and a guide element which can be set up on a floor, and a movement the table top (3) leads to the floor.

15. Method for operating a lifting mechanism (2) according to one of the preceding claims, with the following steps:

Introduction of a force through the introduced linear movement in the linear mechanism (7);

Converting the force introduced by the linear mechanism (7) into a converted torque in the direction of a converted rotational movement; and 30

Application of a counter-torque to the converted torque by the braking device (5) separate from the linear mechanism (7), so that the converted rotational movement is braked.

16. The method according to claim 15 with a lifting mechanism (2) according to one of claims 3 to 10, wherein the converted rotational movement causes the output shaft (13) to rotate relative to the drive shaft (12) and the roller rotates by rotating the third driver contour in the predetermined direction of rotation to the second driver contour between the inner wall of the through hole (15) and the third driver contour, so that the counter-torque is applied, and the jamming by twisting the second driver contour in the predetermined direction of rotation to the third driver contour or by twisting the third Driver contour is released counter to the predetermined direction of rotation to the second driver contour.

17. The method according to claim 15 with a lifting mechanism (2) according to claim 11 or 12, wherein the counter-torque due to a lack of energy supply to the stationary electric holding magnet (32) by a magnetic force of the electric holding magnet (32) on the armature disk (31) is produced.

18. The method according to claim 15 with a lifting mechanism (2) according to claim 13, wherein the counter-torque by the means of the elastic element (43) in the biasing direction on the friction disc (41) pressed pressure element (44) due to the absence of the release force due to the absence the energy supply of the electromagnet (45) is generated.