Sensor assembly, actuator, control system, electrically adjustable piece of furniture and method for operating an electrically adjustable piece of furniture
11662200 · 2023-05-30
Assignee
Inventors
Cpc classification
International classification
Abstract
A sensor assembly for an electrically adjustable piece of furniture having at least one actuator for adjusting a component and a control for the actuator comprises a light transmitter and a light receiver which are coupled to one another via an optical light path. An aperture element which is configured to at least partially cover the light path and which is mounted in a movable manner with respect to the light path in such a way that a change in a position of the aperture element results in a change in the covering of the light path. An evaluation circuit regulates a light quantity emitted by the light transmitter to a reference quantity by means of a control signal and generates a deformation signal based on the control signal or on a signal derived from the control signal. The aperture element converts a deformation or movement of the component into a change of position of the aperture element relative to the light path.
Claims
1. A sensor assembly for an electrically adjustable piece of furniture, which comprises at least one actuator that includes and is to be driven by an electric motor and that is adapted for adjusting an adjustable component of the piece of furniture and a control system for controlling the at least one actuator, the sensor assembly comprising: a light transmitter and a light receiver coupled to each other via an optical light path, wherein the light receiver is configured to provide a reception signal based on a received amount of light; an aperture element which is configured to at least partially cover the light path and which is mounted in a movable manner with respect to the light path in such a way that a change in a position of the aperture element results in a change in a covering of the light path; and an evaluation circuit configured to control an amount of light emitted from the light transmitter via a control signal that is generated based on minimizing a difference between the reception signal and a reference signal, and to generate a deformation signal based on the control signal or on a signal derived from the control signal; wherein the sensor assembly is configured to be mounted in the piece of furniture such that the aperture element is configured to convert a deformation or movement of the adjustable component of the piece of furniture into a change in the position of the aperture element relative to the light path.
2. The sensor assembly according to claim 1, wherein the evaluation circuit comprises a filter stage and is configured to generate the deformation signal by filtering the control signal or the signal derived from the control signal using the filter stage.
3. The sensor assembly according to claim 2, wherein the filter stage is designed as a low-pass filter stage and a differentiator is connected downstream of the low-pass filter stage, or wherein the filter stage is designed as a band-pass filter stage.
4. The sensor assembly according to claim 1, wherein the light path is shorter than 2 cm, in particular shorter than 1 cm.
5. The sensor assembly according to claim 1, wherein the light path is a direct optical connection for transmitting light from the light transmitter to the light receiver, in particular without a use of reflections.
6. The sensor assembly according to claim 1, wherein the aperture element has a shape of any one of the following: a cone; a truncated cone; a pyramid; a truncated pyramid; a cylinder; and a cuboid.
7. The sensor assembly according to claim 1, in which the aperture element comprises a cross-sectional area perpendicular to the light path which is at least partially formed by at least one of the following shapes: a rectangle; a triangle; a trapezoid; a circle segment; a ellipse segment.
8. The sensor assembly according to claim 1, wherein the aperture element is adapted to be fixedly mounted to the adjustable component for producing the change in position of the aperture element relative to the light path.
9. The sensor assembly according to claim 1, where the aperture element is mounted elastically in the sensor assembly and is arranged to produce the change in position of the aperture element relative to the light path via touching of the adjustable component.
10. The sensor assembly according to claim 1, wherein the light transmitter and the light receiver are arranged on a common printed circuit board.
11. The sensor assembly according to claim 10, wherein the light path is parallel or substantially parallel to a surface of the printed circuit board.
12. The sensor assembly according to claim 10, wherein the printed circuit board has an opening below the light path, the aperture element being mounted movably above and/or in the opening.
13. The sensor assembly according to claim 10, further comprising a housing in which the printed circuit board is arranged.
14. The at least one actuator for the electrically adjustable piece of furniture, wherein the piece of furniture comprises the control system for controlling the at least one actuator, the at least one actuator for being driven by the electric motor and set up for adjusting the adjustable component of the piece of furniture, and the sensor assembly according to claim 1, wherein the sensor assembly is arranged in a housing of the at least one actuator and the aperture element is fixed in the at least one actuator in such a way that a deformation or movement of the adjustable component via a deformation or movement of an end shield of the at least one actuator is convertible into the change in the position of the aperture element relative to the light path.
15. The control system for the electrically adjustable piece of furniture, wherein the piece of furniture comprises the at least one actuator that is to be driven by the electric motor and is adapted for adjusting the adjustable component of the piece of furniture, the control system, and the sensor assembly according to claim 1, wherein the control system is configured to control the at least one actuator and is configured to be mounted onto the adjustable component, and wherein the sensor assembly is integrated in a housing of the control system.
16. The control system according to claim 15, wherein a printed circuit board of the sensor assembly is formed by a printed circuit board of the control system.
17. The control system according to claim 15, wherein the control system is configured to detect a collision based on the deformation signal, in particular based on a change in the deformation signal, and to stop the at least one actuator in the event of a detected collision and/or to switch over a direction of movement of the at least one actuator.
18. An electrically adjustable piece of furniture, comprising: at least one actuator that includes and is to be driven by an electric motor and that is adapted for adjusting an adjustable component of the piece of furniture; a control system for controlling the at least one actuator; and at least one sensor assembly, wherein the at least one sensor assembly comprises: a light transmitter and a light receiver coupled to each other via an optical light path, wherein the light receiver is configured to provide a reception signal based on a received amount of light; an aperture element which is configured to at least partially cover the light path and which is mounted in a movable manner with respect to the light path in such a way that a change in a position of the aperture element results in a change in a covering of the light path; and an evaluation circuit configured to control an amount of light emitted from the light transmitter via a control signal that is generated based on minimizing a difference between the reception signal and a reference signal, and to generate a deformation signal based on the control signal or on a signal derived from the control signal; wherein the at least one sensor assembly is mounted in the piece of furniture in such a way that the aperture element is configured to converts a deformation or movement of the adjustable component of the piece of furniture into the change in position of the aperture element relative to the light path.
19. A method for operating an electrically adjustable piece of furniture comprising at least one actuator that includes and is to be driven by an electric motor and that is adapted for adjusting an adjustable component of the piece of furniture, and at least one sensor assembly, the at least one sensor assembly having a light transmitter and a light receiver which are coupled to one another via an optical light path, as well as an aperture element which is configured to at least partially cover the light path and which is mounted in a movable manner with respect to the light path in such a way that a change in a position of the aperture element results in a change in a covering of the light path, the method comprising: transmitting a first quantity of light from the light transmitter via the light path to the light receiver; generating, by means of the light receiver, a reception signal based on a second amount of light received via the light path; converting a deformation or movement of the adjustable component of the piece of furniture into a change in the position of the aperture element relative to the light path; controlling a first amount of light by means of a control signal that results from minimizing a difference between the reception signal and a reference signal; generation of a deformation signal based on the control signal or on a signal derived from the control signal; detecting, based on the deformation signal, in particular based on a change in the deformation signal, a collision of the adjustable component of the piece of furniture; and terminating a movement of the at least one actuator and/or switching a direction of movement of the at least one actuator in case of a detected collision.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the following, the invention is explained in detail on the basis of exemplary embodiments with reference to the drawings. Components which are functionally identical or have an identical effect may be provided with identical reference marks. Identical parts or parts with identical function may be explained only with reference to the figure in which they first appear. The explanation is not necessarily repeated in subsequent figures.
(2) In the figures:
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DETAILED DESCRIPTION
(17)
(18) A sensor assembly 200 is also attached to the table top 115, which can be used to detect the effect of a force on the table top 115, whereby the effect of the force causes a deformation of the table top 115 and this deformation is detected by the sensor assembly 200. A possible application of such a sensor assembly 200 is, for example, the detection of a force due to a collision of the table top 115 with another object or body.
(19) In particular, the sensor module 200 has a communication connection to the control system 140, not shown, in order to transmit corresponding signals. This can be wired or wireless. Deviating from the illustration in
(20) The function and mode of operation of the sensor assembly 200 is explained in detail using the following figures. For example,
(21) With reference to
(22) While
(23) The arrangement shown leads to the fact that the aperture element 240 allows more or less light to pass between light transmitter 210 and light receiver 220 via the light path 215, depending on the deformation. In other words, the aperture element 240 realizes a position dependent attenuation of the emitted light.
(24) A control circuit not shown, which is explained in connection with
(25) The component 250, for example, corresponds the table top 115. During operation of the table shown in
(26) Determining the amount of light currently emitted gives information of a relative measure for the momentary coverage of the light path 215 by the aperture element 240, or of the deformation or of the acting force. The distance between light transmitter 210 and light receiver 220 is small, for example less than 2 cm, in particular less than 1 cm. Light transmitter 210 and light receiver 220 operate in the infrared light range, for example.
(27) In various embodiments, the circuit board 230 has an opening under the light path 215 through which the aperture element 240 can be passed. As shown schematically, the aperture element 240 optionally moves perpendicular to the light path 215 or to the surface of the PCB 230. If necessary, deviations in the range of 5° to 10° are possible. Thus, the light path 250 or the parallel PCB 230 forms a kind of reference line to which the deformation refers.
(28) The light transmission via the light path 215 from the light emitter 210 to the light receiver 220 is based on direct optical transmission and is in particular not dependent on reflectors or similar devices that catch stray light from the light path 215 or otherwise transmit light from the light emitter 210 to the light receiver 220. The use of one or more optical fibers is also not required.
(29) The shape of the aperture element 240 can be selected in different ways. For example, aperture element 240 has the shape of a cone, truncated cone, pyramid, truncated pyramid, cylinder, cuboid, truncated cone or a shape composed of several of the above-mentioned forms combined.
(30) Depending on the shape of the aperture element 240, a specific cross-section or a cross-sectional area of the aperture element 240 is formed, which is perpendicular to the light path 215. With reference to
(31)
(32) In
(33) In the illustration in
(34) Regardless of the shape of the cross-sectional area, for example, the position of the aperture element 240 within the light path 215 is selected so that without the application of force, i.e. in a resting or idle state, the quantity of light emitted is greater than the quantity of light received by a predefined factor, for example approximately twice as much. With reference to
(35) With reference to
(36) For example, the light emitter 210 is a LED or a laser and the light receiver 220 is a photodiode, so that, for example, the current through the LED or laser is defined by the control signal ST′. The brightness control of light-emitting diodes or other light-emitting elements is sufficiently known and will therefore not be discussed in detail at this point. The essential idea is to keep the received light quantity or the resulting received signal ES constant.
(37) The block diagram 500 also contains a processing block 530, which generates a deformation signal DS from the control signal ST or the control signal ST′. The processing element 530, for example, features a combination of amplification and filtering that prepares the control signal ST or the control signal ST′ in such a way that it can be evaluated more reliably.
(38) The control signal ST is used, for example, as a measure of the degree of deformation or the force applied to the adjustable component or the position or change in position of aperture plate 240.
(39) Typically, a bandpass is used as a filter to filter out high-frequency interfering signals that have nothing to do with the application of force on the one hand, and to suppress low-frequency slow signal changes that are not caused by a change in force due to a collision on the other.
(40) In order to optimize the control signal ST or the control signal ST′ with regard to the detection of the change in the force effect, a differentiator can also be used in block 530. Since a differentiator also has a high-pass effect, a low-pass filter in combination with the differentiator can also achieve a band-pass behavior instead of a band-pass filter.
(41) With a differentiator it can be achieved in particular that signal changes in the control signal ST are better visible in the signal course and thus easier to evaluate, because the differentiator can generate pulse-like signal courses at the output from fast voltage changes at its input.
(42) Filter, amplifier and differentiator are not only to be seen as sequentially arranged, individual circuit groups, but can also be combined at least partially or completely with operational amplifier circuits, for example.
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(44) In these embodiments, a force is transmitted between component 250 and aperture element 240 exclusively via contact between the two elements. In addition, deformation of component 250 in turn causes a change in the position of aperture element 240 and thus a change in the degree of coverage of the light path 215. However, with the shown arrangement of the aperture element 240, with reference to
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(46) In the embodiment shown, the housing 270 of the sensor assembly is attached to component 250 via elastic or spring fasteners 265. The aperture element 240 is rigidly attached to component 250 similar to
(47) In the different embodiments, the sensor assembly is shown with its own housing 270. This enables the sensor assembly to be placed on the piece of furniture independently of the control unit, in particular on the adjustable component, in order to detect the application of force or deformation or movement there. If required, it is also possible to attach several such sensor assemblies, each with its own housing, to a piece of furniture. This can be useful to increase the detection accuracy of a larger adjustable component on which at least two sensor assemblies are mounted. Alternatively or additionally this can be useful if the piece of furniture has several different adjustable components on which at least one sensor assembly is mounted.
(48) Alternatively, the sensor assembly can also be integrated directly into a housing of the control unit. In this case, the light path 215 with the light emitter 210 and light receiver 220, for example, is directly provided on a circuit board of the control system. This can be particularly advantageous for a control system for an electrically height-adjustable table, which is mounted on the height-adjustable table top, for example.
(49)
(50) During operation of the actuator 800, a force F, shown by the arrow on the right side, usually acts in the axial direction of the drive shaft 810 and thus also on the end shield 850. In this design, the aperture element 240 is rigidly connected to the end shield. The end shield 850 itself, for example, has a certain elasticity or is elastically mounted in the housing. This means that there are similarities or analogies to the design shown in
(51)
(52) Similar to the design of
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(54) With the appropriate application of force, represented by the force arrow F, the elastic element 1050 can be compressed and/or deformed, which ultimately leads to a relative change in position of the aperture element 240 with respect to the light path 215. For example, the application of force changes the thickness of the elastic element 1050, which is schematically shown with the shaded or full-surface filling of the elastic element 1050. In addition, the elastic element can also be bent to follow a deformation of the component, which in turn leads to a relative change in position of the aperture element 240 with respect to the light path 215. The elastic element 1050 can also be described as a damper or buffer and is made of a rubber-like material, for example.
(55) The change in position of the aperture element 240 can be used to determine a deformation signal according to the principle described above.
(56) The different embodiments of the sensor assembly can be used as an individual single sensor, integrated in a control system or integrated in an actuator, in various electrically adjustable furniture. As a first example, we refer to the implementation for an electrically height-adjustable table shown in
(57) For example,
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(61) While
(62) Since the sensor assembly 200 is mounted on the table top 115, the sensor assembly 200 moves upwards with the table top 115 and thus changes its position relative to the aperture element 240. In this case, therefore, movement of the sensor assembly 200 results in a change in the position of the aperture element 240.
(63) If the table top 115 releases the collision with the obstacle by moving upwards, it rests again on the longitudinal beam due to its elasticity or gravity.
(64) In this version, the sensor assembly 200 can also be integrated into the control unit of the adjustable furniture, so that with reference to
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(66) With reference to
(67) Another possibility is, for example, the implementation in an electrically adjustable bed, as shown in
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(69) The use of the sensor assembly in other adjustable furniture is not excluded.