Patent Grant
11812852
This application is a U.S. National Stage of PCT/HU2020/050037, filed Aug. 6, 2020, which claims priority to Hungarian Application No. P1900293, filed Aug. 15, 2019, each of which is incorporated herein by reference.
The present invention relates to an actuator system for a table with at least two table legs of variable length and a table top held by the table legs.
The invention further relates to a multifunctional table having at least two table legs of variable length and a table top held by the table legs and comprising an actuator system according to the invention.
Tables are used in many different environments for different purposes. The tables are mostly used by seated persons and can serve as a room divider, workstation or dining table, for example. However, tables are used not only for sitting activities, but also for standing receptions or standing people, for example. Where tables are used for multiple purposes, ideally the tables are designed so that their height should be ergonomically appropriate for the purpose. For example, the height of a typical table top designed for a seated user is approx. 70-76 cm, while for tables designed for standing purposes, this value is approx. 100-115 cm. In order to avoid having to use different tables for tasks requiring different table heights, height-adjustable tables have been created, the height of which can be adjusted according to the way it is used. Most height-adjustable tables in the prior art have telescopic legs that have some kind of counterweight mechanism. The simplest such mechanisms include springs, such as those disclosed in U.S. Pat. No. 3,140,559 or 4,981,085. In U.S. Pat. No. 4,559,879, the height of the table is adjusted by means of pulleys and cables, but there are also solutions using air springs arranged in the table legs. The disadvantage of the solutions presented above is that the user has to move the table himself, which can be especially problematic with a higher weight packed on the table. Although counterbalanced mechanics provide a solution to this problem, they either increase the weight of the table or are expensive due to their complex design. The other disadvantage is that when moving manually, the previous height settings are lost, i.e. the user has to set the desired heights again and again.
The above disadvantages are partially eliminated by the solutions in which the movement is done by electric motors. Such an electrically adjustable height table is also described, for example, in U.S. Pat. No. 6,546,880, the essence of which is that in both legs of the table there is a complex moving mechanism comprising gears and a chain, which are driven by an electric motor through a shaft. The advantage of electric movement is that the user can comfortably adjust the height even when more weight is placed on the table. However, the disadvantage is that the even movement of the table legs can be ensured only with the help of complicated mechanics or electronic motion control devices, and the storage of the already set heights is not solved here either.
There is a need for actuator system that can easily and reliably adjust the height of the table legs without complicated mechanics and electronic motion control devices, i.e. that ensures that the displacements and movement speeds of the table legs are the same during height adjustment.
It has been found that using at least two master cylinders operated by a drive unit and mechanically connected to each other, and using slave cylinders connected to the master cylinders by means of conduits ensuring fluid flow, the simultaneous and continuous adjustment of the table legs can be provided easier and in a more efficient way compared to the known solutions.
It has also been found that using a central IT unit which is electronically connected to the drive unit and which is capable of controlling the drive unit, the user-set table height values can be stored and thus easily restore them as required.
It has also been found that if the central IT unit is provided with a communication module for establishing a wireless data connection, preferably a Bluetooth connection, with an external device and if the central IT unit is configured to be controlled via the wireless data connection, a table can be created whose height can be adjusted remotely using an external device (such as a smartphone).
The objects of the invention are to provide an actuator system and a multifunctional table comprising such an actuator system, which are free from the disadvantages of the prior art solutions, i.e. by means of which the table legs can be adjusted simultaneously without the use of complicated mechanics and motion control electronics.
These objects are achieved by an actuator system according to claim 1.
These objects are further achieved by a multifunctional table according to claim 13.
Further advantageous embodiments of the invention are defined in the attached dependent claims.
Further details of the invention will be explained by way of exemplary embodiments with reference to the figures.
The system 100 according to the invention comprises at least two master cylinders 10 having a cylinder 10a and a piston 10b movable in the cylinder 10a and a piston rod 10c for moving the piston 10b. In the context of the present invention, the master cylinder 10 is an energy conversion device that converts the linear kinetic energy of the piston 10b into the compressive energy of a fluid 30 pressed from the cylinder 10b by the piston 10b, as is known to those skilled in the art. The fluid 30 may be, for example, compressed air (i.e., gaseous) or hydraulic oil (or other fluid). The fluid 30 is in a cylinder space 11 defined by the inner surface of the cylinder 10a and the side of the piston 10b opposite the piston rod 10c. Preferably, there is a seal and a slip ring between the piston 10b and the cylinder 10a, as will be apparent to those skilled in the art. The cylinder space 11 is provided with an opening 12 of a diameter smaller than that of the cylinder 10a, which allows the fluid 30 to flow in and out of the master cylinder 10.
A slave cylinder 20 having a cylinder 20a and a piston 20b movable in the cylinder 20a for changing the length of the table leg 210 is connected to each of the master cylinders 10 by means of a conduit 40 allowing fluid 30 flow between the master cylinder 10 and the slave cylinder 20. The slave cylinder 20 has a piston rod 20c which is similar to or identical to the master cylinder 10 and which is optionally attached to the piston 20b. In a preferred embodiment, in which the fluid 30 is a liquid, the piston rod 20c is indirectly connected to the piston 20b by means of a locking element 23, i.e. the piston rod 20c is not fixedly attached to the piston 20b. The locking element 23 is fixed to the piston rod 20c, for example by welding or screwing, but optionally parts of the piston rod 20c and the locking element 23 can also be formed as a single element. The locking element 23 is formed as to prevent the piston rod 20c from being removed from the piston 20b and to allow it to be moved towards the piston 20b. An exemplary embodiment of the locking element 23 is shown in
The inner surface of the cylinder 20a and the piston 20b define a cylinder space 21 filled with fluid 30. The cylinder space 21 is provided with an opening 22 having a diameter smaller than that of the cylinder 20a to allow the fluid 30 to flow in and out of the master cylinder 20. In the context of the present invention, the connection of the master cylinder 10 and the slave cylinder 20 means that a fluid flow is provided between the cylinder spaces 11, 21 by means of the conduit 40 by connecting the ends of the conduit 40 to the openings 12, 22. In this way, the fluid 30 can flow from one cylinder space 11, 21 to the other cylinder space 21, 11 as a result of the displacement of the piston 10b. In a preferred embodiment, the master cylinders 10 and the slave cylinders 20 are hydraulic cylinders, preferably single-acting hydraulic cylinders. In this case, the fluid 30 is in a liquid state, such as hydraulic oil, and the fluid 30 is present only on one side of the pistons 10b, 20b. The conduit 40 may be a rigid or, optionally, flexible wall conduit suitable for conveying fluid 30.
The piston rods 10c of the master cylinders 10 according to the invention are mechanically connected to each other by means of a rigid connecting element 45, such as a metal rod, so that the pistons 10b can only be moved together and only simultaneously within the cylinders 10a. The master cylinders 10 are preferably arranged directly next to each other, for example as shown in
In a particularly preferred embodiment shown in
The movable part 56b is connected to the second end 51a″ via a freewheel 55 which closes when the ball screw 51a rotates in one axial direction and which opens when the ball screw 51a rotates about the other axial direction. The freewheel 55 is configured to break the torque connection between the second end 51a″ and the movable part 56b″ in the direction of rotation of the ball screw 51a required to raise the table top 220. In this case the second end 51a″ can rotate freely without transmitting torque to the movable part 56b. On the other hand, in the direction of rotation required to lower the table top 220, the freewheel 55 closes, i.e. a torque connection is provided between the second end 51a″ and the movable part 56b.
There is a frictional connection between the movable part 56b and the stationary part 56a, i.e. the movable part 56b can only be rotated at a non-negligible torque with respect to the stationary part 56a due to the frictional forces between the stationary part 56a and the movable part 56b. The frictional connection is preferably provided by means of a brake disc 57 fixed to the freewheel 55 and pressed against the stationary part 56a. On each side of the brake disc 57 there are friction elements 57a preferably made of plastic. In a particularly preferred embodiment, the clutch 56 comprises clamping bolts 59, preferably spring clamping bolts 59, screwed into the stationary part 56a, pressing the brake disc 57 to the stationary part 56a, by means of which the strength of the frictional connection between the stationary part 56a and the movable part 56b can be adjusted to the desired value.
The frictional forces provided by the friction elements 57a generate a frictional torque when the brake disc 57 begins to rotate as the stationary part 56a is stationary. In the case where the ball screw 51a rotates in a certain direction, i.e. the table top 220 rises, the brake disc 57 remains stationary because the freewheel 55 opens in this direction of rotation, i.e. the sleeve 13 formed in its bore can rotate freely with negligible rolling resistance. When the drive unit 52 is turned off, so that the table top 220 does not rise further, the ball screw 51a would start to rotate backward due to the constant gravitational force acting on the table top 220. At this direction of rotation, the freewheel 55 closes, i.e. a drive is formed. The friction elements 57a generate a determinable and adjustable frictional torque on the brake disk 57, thereby braking the ball screw 51a. The resulting frictional torque can be controlled and adjusted by tightening the clamping bolts 59 to the appropriate torque, selecting the material of the friction elements 57a, and selecting the working diameter of the brake disc 57. When it is necessary to lower the table top 220, the drive unit 52 rotates the ball screw 51a through the drive shaft 53. At this direction of rotation, the brake disc 57 also rotates, and the power of the drive unit 52 is required to move it, however this power is only a fraction of the power required to lift the table 200. This solution ensures that the ball screw 51a operates with high efficiency in the lifting direction, while the system is self-locking.
In another exemplary embodiment, the drive connection 50 is formed by a rack and the drive unit 52 rotates a gear which fits into the teeth of the rack (not shown in the figures). In addition to the above, of course, other known rigid drives are possible, as is apparent to those skilled in the art.
In a preferred embodiment, the drive unit 52 is provided with a transmitter 54 configured to determine the position of the pistons 10b of the master cylinders 10 within the cylinders 10a. The transmitter 54 may be any sensor known to those skilled in the art (e.g., laser, magnetic, inductive, potentiometer, etc.) that is capable of directly or indirectly determining the position of the rigid system formed by the pistons 10b, piston rods 10c, and connecting element 45. In one possible embodiment, the transmitter 54 is configured as an optical odometer, preferably arranged on the drive connection 50. An optical odometer is a device for constructing an optical, non-contact, incremental or, preferably, absolute measuring system comprising a plurality of scales with transparent and opaque divisions and a reading head, such as a photoelectric sensor, for detecting and processing the information on the scale.
In a particularly preferred embodiment, the system 100 includes a central IT unit 60 electronically connected to the drive unit 52 for controlling the drive unit 52, and which is preferably arranged in the table top 220. The central IT unit 60 is configured to operate the drive unit 52. The term central IT unit 60 is broadly understood herein to include all hardware devices suitable for data collection, processing, and control of the drive unit 52, such as a computer, SoC (System on a Chip), microcontroller, and the like. In a particularly preferred embodiment, the central IT unit 60 stores a plurality of control programs for setting the position of the connecting member 45, and thereby the position of the pistons 10b, and the central IT unit 60 is configured to execute the stored one or more control programs. In the context of the present invention, a control program is a sequence of instructions written in any programming language and executable by the central IT unit 60 and stored as a bit set, which determines the position of the pistons 10b within the cylinders 10a. That is, different control programs define different 45 connector positions.
In a preferred embodiment, the central IT unit 60 includes a communication module 62 for making a wireless data connection 400, preferably a Bluetooth connection, to an external device 300, and the central IT unit 60 is configured to be controlled via the wireless data connection 400. Note that in addition to Bluetooth, other wireless technologies, e.g. ZigBee, WIFI is also applicable, as is obvious to a person skilled in the art. The central IT unit 60 can be connected to a local or global network (e.g., the Internet) via the data connection 400, and the data received and processed by the central IT unit 60 can be retrieved remotely from the central IT unit 60 via the network, or the central IT unit 60 can be remotely controlled by the external device 300 (e.g., a smartphone or tablet) via the network. In this case, the operation of the drive unit 52, i.e. the position of the pistons 20b and 10b—indirectly connected by means of the conduit 40—(thus ultimately the dimensions of the table legs 210) can be controlled manually (e.g. by using a smartphone) or the control programs can be selected using the smartphone.
In a preferred embodiment, the system 100 includes a user interface 64 electronically connected to the central IT unit 60, as shown, for example, in
The invention further relates to a multifunctional table 200 having at least two table legs 210 of variable length and a table top 220 held by the table legs 210, the table 200 comprising an actuator system 100 according to the invention. In the following, together with the description of the table 200, the operation of the system 100 will be described.
By means of the user interface 64 or the external device 300, the drive unit 52 is actuated, during which the connecting element 45 and the pistons 10b therewith are moved—depending on the direction of height adjustment—in the corresponding direction via the first drive connection 50. The drive unit 52 may be operated manually, for example, by pressing the appropriate buttons on the user interface 64 or the external device 300, or automatically by selecting a control program. For example, if the height of the table top 220 is to be increased, the cylinder spaces 11 of the master cylinders 10 are reduced by moving forward the connecting element 45, the piston rods 10c and the pistons 10b, thereby the fluid 30 in the cylinder spaces 11 flows into the cylinder spaces 21 of the slave cylinders 20 through the conduits 40 due to the increased pressure. Hence, the volume of the cylinder spaces 11 decreases, the volume of the cylinder spaces 21 increases (see
When the table 200 is lifted or transported, the pistons 20b are subjected to a pulling force due to the weight of the movable elements 212 and the center members 214, which tends to increase the volume of the cylinder spaces 21. If the fluid 30 is a liquid, the pressure in the cylinder space 21 decreases and a vacuum is created. In this case, the atmospheric pressure on the outer surface of the piston 20b will be higher than the vacuum in the cylinder space 21, so that the atmospheric pressure will create an inward compressive force, which is opposite to the tensile force. Due to the small diameter of the pistons 20a and therefore their small effective surface, the force generated by the atmospheric pressure is always overcome by the tensile force, i.e. even with a small tensile force the pistons 20b move, thus increasing the length of the cylinder 20. In practice, due to the above, when the table top 220 is lifted, the length of the table legs 210 increases as long as the structure allows. That is, the table 200 can only be lifted off the ground if the table top 220 is raised to the maximum height defined by the structure, and then the table legs 210 are already raised. This is both inconvenient and dangerous, as raising and lowering the table 200 can cause the table top 220 to fall if it is not lifted from the highest position. In the case of embodiments with locking elements 23, this problem does not arise, since the locking element 23 described above prevents the piston rod 20c from being removed from the piston 20b, i.e. increasing the length of the cylinders 20 and the table legs 210 by pulling.
In a preferred embodiment, the various user-set positions of the table 200 can be stored in the central IT unit 60 in the form of control programs. In this case, physical or virtual memory buttons are provided on the user interface 64 or the external device 300 to create and call up the particular control program. Thus, the given height setting (similar to memory car seats) can be assigned to the button, for example, by holding down the given memory button and the height can be retrieved automatically by pressing the button once.
In a preferred embodiment, the table 200 includes one or more sensors 65 in data communication with the central IT unit 60. Said one or more sensors 65 are selected from a group consisting of a humidity meter, a carbon dioxide sensor, a temperature gauge and an air pressure gauge. The data measured by the one or more sensors 65 is preferably transmitted to the external device 300 via the communication module 62 of the central IT unit 60 (e.g. via a Bluetooth connection). In this way, based on the measured data, the user is informed (e.g. by a mobile application running on the external device 300) about the current ambient air quality, temperature, etc., or the application may send an alert if e.g. the air quality is low.
In the embodiment shown in
Preferably, the table 200 further includes one or more built-in speakers 227, preferably a Bluetooth speaker and/or a built-in light source 228, preferably an LED light source. For example, the speakers 227 may be incorporated into the table top 220 and the light sources 228 into the table legs 210, as shown in
Preferably, the table 200 further comprises a preferably tiltable socket board 229 with a mains socket and a USB charging socket built into the table top 220, an exemplary embodiment of which is shown in
Various modifications to the above disclosed embodiments will be apparent to a person skilled in the art without departing from the scope of protection determined by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1900293 | Aug 2019 | HU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/HU2020/050037 | 8/6/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/028704 | 2/18/2021 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7270062 | Larson | Sep 2007 | B1 |
| 10561233 | Lin | Feb 2020 | B1 |
| 11497304 | Pan | Nov 2022 | B1 |
| 20200154881 | Applegate | May 2020 | A1 |
| 20220087410 | Stiefelmaier | Mar 2022 | A1 |
| Number | Date | Country |
|---|---|---|
| 10321319 | Dec 2004 | DE |
| Number | Date | Country | |
|---|---|---|---|
| 20220304462 A1 | Sep 2022 | US |
