Telescopic column with separate transmission shaft

Abstract

The invention relates to a telescopic column (10) having three column elements (12, 14, 16) arranged at least partially inside one another according to a predetermined sequence, a first gear mechanism (18), and a first threaded spindle (20) which can be rotatably driven by means of the first gear mechanism (18) and is axially fixed relative to an outermost column element (12) of the three column elements (12, 14, 16). Furthermore, the telescopic column (10) has a transmission shaft (22), which is formed separately from the first threaded spindle (20) and is arranged at a distance from and substantially parallel to the first threaded spindle (20) and which can be rotatably driven by means of the first gear mechanism (18) and is axially fixed relative to the outermost column element (12). Moreover, a second gear mechanism (24) is provided, which can be driven by means of the transmission shaft (22) and which is linearly movable along a lifting direction (26) of the telescopic column (10). In addition, a second threaded spindle (28) is provided, which can be rotatably driven by means of the second gear mechanism (24) and is axially fixed relative to a central column element (14).

Description

[0001] Telescopic column with separate transmission shaft

[0002] The invention relates to a telescopic column and a method for operating the telescopic column.

[0003] Telescopic columns for lifting loads are already known, typically comprising two or more nested column elements arranged like boxes. Using these column elements and an internal mechanism, heavy loads can be lifted, lowered, or lifted in or against the direction of travel of the telescopic column. Such telescopic columns have also proven particularly effective for lifting and moving eccentric loads. In its retracted state, the column elements are usually nested within each other to minimize the overall height of the telescopic column. To achieve a long stroke, the mechanism often incorporates one or more threaded spindles or cable pulley systems coupled with a screw thread. This allows the column elements to be extended or retracted simultaneously.If the mechanism has two threaded spindles, these are often arranged parallel to each other and coupled in such a way that different column elements can be actuated with each spindle. However, this means that a load acting on the upper threaded spindle, as well as dynamic forces, must be absorbed by a threaded spindle located below it. This can lead to high wear, thus reducing the service life of such a telescopic column. Furthermore, the maximum load-bearing capacity of the telescopic column may be limited for this reason. Moreover, the design of such a telescopic column is very complex.

[0004] The invention is based on the objective of providing an improved telescopic column. In particular, it is an objective of the invention to provide a telescopic column with improved load-bearing capacity, which is preferably inexpensive to manufacture.

[0005] This problem is solved by a telescopic column having the features of independent claim 1. Furthermore, the present invention is based on the objective of providing a method for operating the telescopic column.

[0006] This problem is solved by a method with the features of a subordinate method claim.

[0007] Advantageous further training courses are each the subject of dependent sub-claims.

[0008] The telescopic column according to the invention comprises three column elements arranged at least partially within one another in a predetermined sequence. Furthermore, the telescopic column according to the invention comprises a first gearbox and a first threaded spindle. This first threaded spindle is rotatably driven by means of the first gearbox. The first threaded spindle is axially fixed relative to an outermost column element of the three aforementioned column elements. The telescopic column also comprises a transmission shaft. This transmission shaft is separate from the first threaded spindle. Furthermore, the transmission shaft is spaced apart from the first threaded spindle and arranged substantially parallel to it. In particular, a longitudinal direction of the transmission shaft is arranged substantially parallel to a longitudinal direction of the separately designed first threaded spindle.Preferably, a longitudinal axis of the first threaded spindle and a longitudinal axis of the transmission shaft are arranged essentially parallel to each other and at a predetermined distance from each other. Furthermore, the transmission shaft is axially fixed relative to the outermost column element of the three column elements. A second gearbox is also provided, which can be driven by the transmission shaft and is linearly movable along a stroke direction of the telescopic column by means of the first threaded spindle. In addition, the telescopic column has a second threaded spindle, which can be driven rotationally by means of the second gearbox. This second threaded spindle is axially fixed relative to a central column element of the three column elements, which is arranged between an outermost and an innermost column element. Advantageously, the second threaded spindle is designed separately from the transmission shaft and the first threaded spindle.Preferably, the second threaded spindle is arranged essentially parallel to the transmission shaft and / or the first threaded spindle.

[0009] In this way, a stable and robust telescopic column can be provided for lifting and / or holding loads. The separate transmission shaft reduces the load on the first threaded spindle. Furthermore, dynamic loads can be distributed across two threaded spindles. In the preferred application, this can halve the dynamic load acting on the threaded spindles, resulting in a long service life for the telescopic column. A wide variety of lifting speeds can also be achieved. Additionally, a telescopic column can be provided that, despite a long stroke, has a low height in its retracted position. Moreover, manufacturing can be simplified. For example, the use of hollow shafts in the production of the threaded spindle and / or the transmission shaft can be eliminated.Furthermore, it is possible to forgo multiple teeth and / or internal teeth.

[0010] Furthermore, the telescopic column according to the invention provides an external motor, which is arranged outside the outermost column element and is operatively connected to the first gearbox. The motor and the outermost column element can remain stationary relative to the other column elements. The outermost column element and the external motor can be arranged side by side on a first side of a mounting section. The outermost column element and the external motor can be arranged on two opposite sides of a mounting section. The mounting section can include the first gearbox. The external motor is preferably aligned parallel to an axis in the feed direction of the telescopic column.

[0011] An externally mounted motor eliminates the need to route the motor inside the telescopic column. Likewise, the associated cable routing is unnecessary. Furthermore, the column sections can be designed independently of the motor's size. Additionally, the external motor allows for easy maintenance without affecting other components of the telescopic column.

[0012] An advantageous further development provides that the transmission shaft has an axially extending groove for the purpose of transmitting torque from the first gearbox to the second gearbox. Advantageously, the axial direction extends along the longitudinal direction of the transmission shaft. This enables reliable torque transmission. Furthermore, it allows for precise and reliable linear guidance of the second gearbox along the transmission shaft. Alternatively or additionally, the transmission shaft can have a bulge, a web, or a spring for the purpose of torque transmission.

[0013] An advantageous embodiment provides that the aforementioned groove forms part of an axial linear guide. Preferably, the linear guide includes a linear ball bearing whose balls are accommodated in the aforementioned groove or in several such grooves. Particularly preferably, the second gearbox is connected to the aforementioned linear ball bearing. Alternatively, a tongue-and-groove connection can be provided as the linear guide. In this case, the transmission shaft can have either the groove or the spring. Particularly preferably, the spring is configured to engage in the aforementioned groove and be guided slidably along it.

[0014] Another advantageous improvement involves using a ball screw for the first and / or second threaded spindle. This allows for high positioning and / or repeatability accuracy. Furthermore, it results in very little play in the telescopic column, thus enabling precise and easy positioning of objects using the telescopic column.

[0015] In a preferred embodiment, the first and second threaded spindles have at least partially identical dimensions. In particular, they have the same nominal diameter and / or the same pitch. This allows for a simple design of the telescopic column. Furthermore, the computational effort required for the design and / or dimensioning of the telescopic column can be minimized.

[0016] Furthermore, an advantageous embodiment provides that the first gearbox and / or the second gearbox are each designed as a traction drive. Preferably, a belt drive is used as the traction drive. Alternatively, a chain drive can be used. In this way, compact and space-saving gearboxes can be used. Furthermore, this allows the weight of the telescopic column to be kept low.

[0017] In a preferred embodiment, the transmission shaft and / or the first threaded spindle are each connected to a pulley of the first gearbox. Furthermore, it can be provided that the first threaded spindle and / or the second threaded spindle are each connected to a pulley of the second gearbox. This enables a cost-effective and reliable drive system.

[0018] In a further advantageous embodiment, a first threaded nut is provided, operatively connected to the first threaded spindle. By means of this first threaded nut, the middle column element of the three column elements is linearly movably connected to the first threaded spindle. Advantageously, the first threaded nut is axially fixed to the middle column element. A rotational movement of the first threaded spindle thus allows the middle column element to move linearly along the longitudinal direction of the first threaded spindle. This enables the middle column element to be moved relative to the outermost column element. In the event of extension of the telescopic column, this ensures high stability and load-bearing capacity. Furthermore, this arrangement protects any mechanism located within the column elements from external influences.

[0019] An advantageous embodiment provides that the second gearbox is movable linearly along the transmission shaft by means of the first threaded nut. The first threaded nut is expediently connected to the second gearbox. By means of a rotary movement of the first threaded spindle, the second gearbox can be moved linearly along both the longitudinal direction of the first threaded spindle and the transmission shaft. This ensures reliable and precise linear guidance of the second gearbox. High torques and / or eccentric loads acting externally on the telescopic column can therefore be reliably and safely absorbed by the second gearbox.

[0020] In another advantageous embodiment, a platform is provided to which the second gearbox and the first threaded nut are connected, and which is linearly movable along the transmission shaft by means of the first threaded nut. This further increases the stability and load-bearing capacity of the telescopic column. Furthermore, it allows for a simple and essentially parallel arrangement of the first threaded spindle and the transmission shaft, even under high torsional loads.

[0021] In a particular embodiment, the platform is connected to the central column element of the three column elements in such a way that the central column element is movable linearly along the transmission shaft by means of the first threaded spindle. Preferably, the platform is axially fixed to the central column element. This allows for cost-effective manufacturing and / or assembly of the telescopic column. The design complexity of the telescopic column can be easily reduced.

[0022] Another advantageous embodiment provides a second threaded nut, which is operatively connected to the second threaded spindle. The innermost column element of the three column elements is also linearly movably connected by means of the second threaded nut. Preferably, the second threaded nut is axially fixed to the innermost column element. This allows the innermost column element to be moved linearly along the longitudinal direction of the second threaded spindle. In this way, an additional increase in the load-bearing capacity and stability of the telescopic column can be achieved.

[0023] Furthermore, the invention provides a method by which the telescopic column according to the invention can be operated. In the method according to the invention, the first threaded spindle and the transmission shaft of the telescopic column according to the invention, which is designed separately and spaced apart and arranged essentially parallel to it, are driven separately by means of the first gearbox of the telescopic column. This allows for a high-performance guide mechanism. Furthermore, it enables rapid extension and retraction. In addition, it allows for a large stroke length with a low height of the telescopic column in a retracted state, while minimizing effort. Finally, it provides a reliable and dependable method for operating the telescopic column.Preferably, the first threaded spindle and the spaced-apart and essentially parallel transmission shaft are driven simultaneously by the first gearbox of the telescopic column. In this way, two threaded spindles can be driven simultaneously by one motor.

[0024] An advantageous further development of the method provides that two of the three column elements of the aforementioned telescopic column are extended or retracted simultaneously relative to a stationary column element. In this way, rapid extension and / or retraction of the column elements can be achieved. Preferably, the two column elements are extended or retracted simultaneously relative to the stationary column element by means of the first threaded spindle, the transmission shaft, and the second threaded spindle. Several column elements of the telescopic column can thus be extended or retracted concurrently.

[0025] In a preferred embodiment, the outermost column element of the telescopic column according to the invention is provided as a stationary column element. With respect to the stationary column element, the remaining two column elements are designed to be extendable and / or retractable in the lifting direction.

[0026] The invention will now be explained in more detail with reference to the figures. Where expedient, elements with the same effect are designated with the same reference numerals. The invention is not limited to the embodiments shown in the figures or their variations – not even with regard to functional features. The preceding description as well as the subsequent description of the figures contains numerous features, some of which are summarized in the dependent subclaims. However, those skilled in the art will also consider these features, as well as all other features disclosed above and in the subsequent description of the figures, individually and combine them into meaningful further combinations. In particular, all the aforementioned features can be combined individually and in any suitable combination with the method and / or the device according to the invention. The figures are schematic drawings not to scale.

[0027] They show:

[0028] FIG 1 shows an embodiment of a telescopic column according to the invention;

[0029] FIG 2 shows a detailed view of a second gearbox of the embodiment of the telescopic column according to the invention shown in connection with Figure 1;

[0030] FIG 3 shows an embodiment of a linear guide along a transmission shaft of the embodiment of the telescopic column according to the invention;

[0031] FIG 4 is an illustration of an example of the method according to the invention.

[0032] Figure 1 shows a schematic representation of an embodiment of a telescopic column 10 in which three column elements 12, 14, 16 can be extended and retracted simultaneously by means of two complementary threaded spindles 20, 28. For clarity, exemplary housing parts and the column elements 12, 14, 16 are shown with dashed lines in Figure 1. Furthermore, Figure 1 illustrates an example of a method 100 for operating the illustrated embodiment of the telescopic column 10.

[0033] The exemplary embodiment of the telescopic column 10 described here has an external motor 40. A first gearbox 18 is operatively connected to the motor 40. For example, a belt drive is provided as the first gearbox 18. A first threaded spindle 20 can be rotatably driven by this first gearbox 18. For this purpose, the first threaded spindle 20 is, for example, fixed to a pulley of the first gearbox 18. In this way, the first threaded spindle 20 is axially fixed relative to an outermost column element 12 of the three column elements 12, 14, 16 in the present exemplary embodiment. Furthermore, the first threaded spindle 20 is designed as a ball screw spindle in this example.

[0034] In the outermost column element 12, a middle column element 14 is arranged, within which in turn an innermost column element 16 is arranged. In the retracted, basic position of the telescopic column, the three column elements 12, 14, 16 are arranged within one another such that a minimum height in the stroke direction 26 is achieved. Immediately adjacent column elements of the three column elements 12, 14, 16 are movably connected relative to each other by means of a guide device 44. To prevent one of the column elements 12, 14, 16 from fully extending out of an immediately adjacent column element 12, 14, 16, limiting elements 42 are provided, for example. This ensures that the three column elements 12, 14, 16 are always at least partially enclosed within one another. This provides a high degree of operational safety and reliability.

[0035] Furthermore, a transmission shaft 22 is rotatably connected to the first gearbox 18. For example, the transmission shaft 22 is connected to another pulley of the first gearbox 18. This transmission shaft 22 is separate from the first threaded spindle 20. Moreover, this transmission shaft 22 is spaced apart and arranged essentially parallel to the first threaded spindle 20. In addition, the transmission shaft 22 is axially fixed relative to the outermost column element 12 of the three column elements 12, 14, 16 due to its connection with the other pulley of the first gearbox 18.

[0036] Furthermore, the telescopic column 10 has a second gearbox 24, which in this case is designed as a further belt drive. This second gearbox 24 can be driven by the transmission shaft 22 and is linearly movable along the stroke direction 26 of the telescopic column 10 by means of the first threaded spindle 20. In a preferred embodiment of the telescopic column 10, a platform 36 is provided to which the second gearbox 24 is connected. The platform 36 also has a first threaded nut 32, which is operatively connected to the first threaded spindle 20. The platform 36 is also fixed to the central column element 14. A rotational movement of the first threaded spindle 20 thus causes a linear movement of the central column element 14 and of the second gearbox 24 along the stroke direction 26.In this way, the second gearbox 24 is reliably and stably guided linearly by means of the first threaded spindle 20 along a longitudinal extension direction of the transmission shaft 22 as well as along a longitudinal extension direction of the first threaded spindle 20.

[0037] Figure 2 shows a detailed view of the second gearbox 24 and the first threaded nut 32. For clarity, this detailed view is shown without the platform 36.

[0038] The second threaded spindle 28 is fixed to a pulley of the second gearbox 24. For the purpose of transmitting torque from the first gearbox 18 to the second gearbox 24, the transmission shaft 22 has an axially extending groove 30. This allows the second gearbox 24 to be guided along the longitudinal direction of the transmission shaft 22 and also enables the aforementioned torque to be transmitted to the second gearbox 24. This allows the second threaded spindle 28 to be driven rotatably by the aforementioned motor 40 via the transmission shaft 22.

[0039] Figure 3 shows a further detailed view of a linear guide 38, by means of which the second gearbox 24 is guided along the transmission shaft 22 in the stroke direction 26. The further detailed view shows a plane that extends essentially perpendicular to said stroke direction 26. The transmission shaft 22 is not a hollow shaft. By way of example, four grooves 30 are provided along the circumference of the transmission shaft 22, each extending in the longitudinal direction of the transmission shaft 22. Balls of a linear ball bearing 46 are arranged in the grooves 30. This allows friction during movement of the second gearbox 24 along the transmission shaft 22 in the stroke direction 26 to be kept as low as possible. Furthermore, this allows for a reliable and precise telescopic column 10. Figure 1 also shows by way of example that a second threaded nut 34 is provided.This second threaded nut 34 is operatively connected to the second threaded spindle 28. Furthermore, the second threaded nut 34 is fixed to the innermost column element 16 of the three column elements 12, 14, 16. In this way, the innermost column element 16 is movable linearly in the stroke direction 26 by means of the second threaded spindle 28.

[0040] In the embodiment of the telescopic column 10 described here, the first threaded spindle 20 and the separate transmission shaft 22, arranged substantially parallel to it, are each driven separately by the first gearbox 18 102. The middle column element 14 is extended or retracted in the stroke direction 26 by means of the first threaded spindle 20 104. The innermost column element 16 is simultaneously extended or retracted by means of the transmission shaft 22, the second gearbox 24, and the second threaded spindle 28 connected to it 104. The outermost column element 12 and the motor 40, on the other hand, remain stationary relative to the other column elements 14, 16. This allows two of the three column elements 14, 16 to be extended or retracted simultaneously relative to the stationary column element 12 104. In the retracted state, a low height of the telescopic column 10 can thus be achieved.Nevertheless, a large stroke length can be provided by means of the two parallel threaded spindles 20, 28. In addition, rapid extension and retraction 104 of the telescopic column 10 can be achieved.

[0041] Figure 4 illustrates the previously described example of a method 100 for operating the telescopic column 10 by means of a schematic flowchart. List of reference symbols

[0042] Telescopic column outermost column element middle column element innermost column element first gearbox first threaded spindle transmission shaft second gearbox stroke direction second threaded spindle groove first threaded nut second threaded nut platform

[0043] Linear guide

[0044] Motor

[0045] Limiting element guide device linear ball bearing

[0046] Proceedings

[0047] Driving simultaneous extension or retraction

Claims

Patent claims 1. Telescopic column (10) comprising: - three column elements (12, 14, 16) arranged at least partially inside each other in a predetermined sequence; - a first gearbox (18); - a first threaded spindle (20) which can be driven rotatably by means of the first gear (18) and which is axially fixed relative to an outermost column element (12) of the three column elements (12, 14, 16); - a transmission shaft (22), which is formed separately from the first threaded spindle (20) and spaced apart and arranged essentially parallel to the first threaded spindle (20), which can be driven rotatably by means of the first gear (18) and which is axially fixed relative to the outermost column element (12) of the three column elements (12, 14, 16); - a second gearbox (24) which can be driven by means of the transmission shaft (22) and which is linearly movable along a stroke direction (26) of the telescopic column (10) by means of the first threaded spindle (20); - a second threaded spindle (28) which can be driven rotatably by means of the second gear (24) and which is axially fixed relative to a middle column element (14) of the three column elements (12, 14, 16) arranged between the outermost and an innermost column element (12, 16); - an external motor (40) which is arranged outside the outermost column element (12) and is operatively connected to the first gearbox (18).

2. Telescopic column (10) according to claim 1 , characterized in that the transmission shaft (22) has an axially extending groove (30) for the purpose of transmitting a torque from the first gearbox (18) to the second gearbox (24).

3. Telescopic column (10) according to claim 1 or 2, characterized in that the first threaded spindle (20) and / or the second threaded spindle (28) is designed as a ball screw spindle.

4. Telescopic column (10) according to one of the preceding claims, characterized in that the first transmission (18) and / or the second transmission (24) is each designed as a traction transmission, preferably as a belt drive.

5. Telescopic column (10) according to one of the preceding claims, characterized in that a first threaded nut (32) operatively connected to the first threaded spindle (20) is provided, by means of which the middle column element (14) of the three column elements (12, 14, 16) is linearly movably connected to the first threaded spindle (20).

6. Telescopic column (10) according to claim 5, characterized in that the second gear (24) is movable linearly along the transmission shaft (22) by means of the first threaded nut (32).

7. Telescopic column (10) according to claim 5 or 6, characterized in that a platform (36) is provided with which the second gearbox (24) and the said first threaded nut (32) are connected and which is linearly movable along the transmission shaft (22) by means of the first threaded nut (32).

8. Telescopic column (10) according to one of the preceding claims, characterized in that a second threaded nut (34) is provided which is operatively connected to the second threaded spindle (28) and by means of which the innermost column element (16) of the three column elements (12, 14, 16) is linearly movably connected to the second threaded spindle (28).

9. Method (100) for operating the telescopic column (10) according to one of the preceding claims, in which the first threaded spindle (20) and the transmission shaft (22) of the telescopic column (10), which is formed separately from the first threaded spindle (20) and spaced apart and substantially parallel thereto, are driven separately by means of the first gearbox (18) of the telescopic column (10) (102).

10. Method (100) according to claim 9, in which two of the three column elements (12, 14, 16) of said telescopic column (10) are extended or retracted simultaneously relative to a stationary column element (12) of the three column elements (12, 14, 16) (104).

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