DEVICE AND METHOD FOR ADAPTING THE CONTOUR OF A BACK ELEMENT TO THE POSTURE OF A PERSON

The invention relates to a device comprising a seat element and comprising a back element connected to the seat element, especially in a tiltable way, for accommodating a sitting or lying person and for adapting the contour of the back element to the posture of the person, and comprising a control unit, with the seat element having at least one bearing pressure sensor connected to the control unit for measuring an actual bearing pressure distribution exerted by the person and with the back element having at least one first actuating element connected to the control unit for changing the contour of the back element.

In addition, the invention exhibits a method of adapting the contour of the back element to the person's posture.

STATE OF THE ART

Users are often not aware of their own individual posture when standing, sitting and lying down and adopt positions that can cause one-sided painful muscle contractures and, in the long run, can lead to attrition processes, including herniated discs, in the event of incorrect loading of the spine and pelvis structure. In particular, sitting for long periods of time requires permanent static work from the muscles, often in a false posture and without sufficient compensatory movements, which causes muscular imbalances and promotes a wide range of physical complaints. The user's pelvis plays a central role in preventing incorrect postures and achieving an optimal position of the body. Devices for positioning the pelvis are widely known from the field of ergonomics. US 2017/0086588 A1 discloses an air chamber system comprising two air chamber elements laterally spaced apart from one another and integrated into the seating surface of a seat, which, when sitting unevenly, positions the pelvis of the seated person by balancing his or her ischial tuberosities by supplying or discharging air by means of a compressor. A portion of the air chamber elements is designed to be movable, whereby the user's femur position is adjustable. In the air chamber elements, contact pressure sensors are incorporated which detect sitting pressures exerted on the seating surface by the user's ischial tuberosities. A controller evaluates the sitting pressures and controls the compressor according to the evaluation.

Furthermore, from WO 2020/215109 A1, a device for positioning the body of a user is known, wherein the device can be integrated into a seat or a lounger or can be used as a support. In this case, the device comprises a seat element, a back element comprising a pelvic and lumbar spine module, and a computer unit, the back element being connected to the seat element, the pelvic and lumbar spine module comprising at least one actuating element and at least one sensor, and the seat element comprising at least one actuating element and at least three sensors, with the sensors being connected to the computer unit and being designed for detecting sitting and bearing pressures of the user in the seat element and in the pelvic and lumbar spine module, with the computer unit being connected to the actuating elements and being designed for evaluating the sitting and bearing pressures and for activating the actuating elements.

However, such devices have the disadvantage that they are of high complexity due to the use of a plurality of sensors and actuating elements and, in addition, cannot be manufactured cost-effectively. Such devices are therefore too expensive for being applied in objects of daily use, e.g., office chairs, and are unsuitable because of the high adjustment and calibration effort.

DISCLOSURE OF THE INVENTION

It is therefore the object of the present invention to improve a device according to the initially mentioned type in such a way that the contour of the back element can be adapted automatically to the posture of the person in a technically simple and cost-effective manner and thus the natural posture of the person is supported in the best possible way.

The invention achieves the object that has been posed with regard to the device in that the control unit is programmed to select a predetermined posture and at least one characteristic target posture parameter matching the predetermined posture, to calculate an actual posture parameter from the actual bearing pressure distribution measured by the bearing pressure sensor and to compare the actual posture parameter with the target posture parameter, and, if the actual posture parameter matches the target posture parameter, to actuate the first actuating element in such a way as to adapt the contour of the back element to the posture of the person.

In doing so, the person can be placed, according to the invention, in a sitting or lying position on the device consisting of a seat element and a back element, with the bearing pressure exerted on the seat element by the ischial tuberosities, the person's coccyx and sacrum, being measured by the bearing pressure sensor provided in the seat element. The actual bearing pressure (or the actual bearing pressure distribution) of the person, which has been measured in this way, can thereby be used for determining their posture or, respectively, their pelvic position. In the back element, a first actuating element is additionally provided, which can be actuated by a control unit and can be adjusted in such a way that the contour of the back element is thereby changed.

By selecting a predetermined posture by the control unit and at least one characteristic target posture parameter matching the predetermined posture, it can be ensured that the person is always in a physiologically correct posture or, respectively, in a pelvic position adjusted to the seating system before the contour of the back element is adapted to their posture, whereby a positive influence is also exerted on the lower lumbar spine area. In this way, errors in adjusting the actuating elements or, respectively, “fixing” of a physiologically incorrect posture can be avoided. Adopting a physiologically correct posture is important in order to prevent incorrect postures from being created and to enable a prolonged sitting or lying position without inappropriate strain, postural damage or consequential damage. According to the invention, a technically simple and cost-effective device can thus be created, which allows reliable body positioning.

Within the meaning of the invention, a physiologically correct posture of the person, especially in passive posture situations, is understood to be a sitting or lying position with a certain angle of inclination of the back element relative to the seat element, in which the body section weights are supported depending on the angle of inclination in that the actuating elements are adapted to the individual body contour in such a way that the skeletal pelvic and spinal structures (coccyx and sacrum) are loaded according to their load-bearing function. The overall positioning of the spine is supported by the pelvic position being adjusted to the seating system in a controlled manner, and, in doing so, especially the muscular stress situation in the lumbar spine segments in its individual form is directly influenced in a positive way, and the shoulder region is also supported in its own dynamics.

Preferably, the seat element can be connected to the back element in a tiltable manner. According to a further embodiment variant, the seat element can be connected to the back element also in an essentially rigid manner.

In this case, the predetermined posture is preferably selected by the control unit based on various possible parameters. For example, numerous different parameters can be used for selecting the predetermined posture, such as the angle between the seat element and the back element, a previously measured actual bearing pressure distribution of the person on the seat element, historical data on the person's preferred postures and/or on known incorrect postures, or comparable parameters. The posture can thereby be selected either dynamically depending on variable parameters, or can also be preset in the control unit (e.g., in case of a device with a fixed seat angle).

In this case, the predetermined posture is assigned at least one corresponding characteristic target posture parameter each, which characterizes the predetermined posture.

According to an embodiment variant of the invention, the target posture parameter can, in this case, be a pelvic rotation angle (or a pelvic tilt) of the person, with at least one pelvic rotation angle about the transverse, sagittal or longitudinal axis being taken into account. The transverse axis thereby lies in the transverse plane and is normal to the sagittal plane of the body. The sagittal axis lies in the sagittal plane and is normal to the frontal plane, and the longitudinal axis lies in the frontal plane and is normal to the transverse plane.

On the other hand, an actual posture parameter related to the person's pelvis can be determined from the measured actual bearing pressure distribution, which reflects the actual posture (pelvic position) of the person on the seat element. The actual posture parameter thereby correlates, in each case, with the selected target posture parameter as described above: if, for example, a pelvic rotation angle about the transverse axis has been selected as the target posture parameter, a pelvic rotation angle about the transverse axis is also determined as the actual posture parameter from the actual bearing pressure distribution, for comparison with the target posture parameter.

The actual posture parameter can be calculated from the actual bearing pressure distribution, for example, based on the positions of the peak pressures in the bearing pressure distribution. For example, depending on the pelvic rotation(s), different bony structures of the pelvis, especially of the coccyx and sacrum, can come into contact with the bearing pressure sensor and can thus generate a specific image of peak pressures—emanating from the respective bony structures. In case of a completely upright sitting position, only two peak pressures emanating from the person's two ischial tuberosities would accordingly be provided. As the back tilt or, respectively, the pelvic rotation about the transverse axis increases, the two ischial tuberosities lose bearing pressure, while the bearing pressure of the coccyx and sacrum increases. When transitioning to the reclining position, the ischial tuberosities will ultimately also lose contact with the seat element, and the bearing pressure distribution is determined by the peak pressures emanating from the sacrum and/or the iliac crests. A detailed description of the relationship between the bearing pressure distribution and posture parameters is exemplified below based on the figures.

Due to the possibility of evaluating individually developed actual bearing pressure distributions based on the above-mentioned known characteristics, which furthermore take into account influences in the pressure transmission (soft tissue, sensor arrangement, etc.), and the comparison with the respective associated posture parameters, such as, e.g., one or several pelvic rotation angles, it is finally possible to reliably infer the respective actual posture parameter. This means that the control unit is able to determine when the person's posture matches the predetermined posture by measuring the actual bearing pressure distribution.

The control unit thus compares the actual posture parameter determined from the measured actual bearing pressure distribution with the target posture parameter at constant intervals, in particular essentially continuously, and detects the point in time at which the two match. If there is a match, the control unit immediately actuates the actuating elements in order to adapt the contour of the back element to the person's posture. In doing so, in particular the contour of the back element can be adjusted in such a way that said element assists in adopting or, respectively, maintaining the correct physiological (predetermined) posture.

Therefore, the device according to the invention can be suited, particularly advantageously, for being integrated into an existing seat or lounger or for being used as a seat cover on a seat or lounger. This results in a variety of possible applications, although the device is not limited to the following examples. The device can be integrated, for example, into the following facilities: into office chairs, wheelchairs, vehicle seats, child restraint systems, workout equipment, mattresses, into loungers or mats in the rehabilitation and therapy sector, or into operating beds.

According to one embodiment variant, the device can furthermore have a second bearing pressure sensor, which is provided in the back element. The second bearing pressure sensor can thus assist the first bearing pressure sensor within the seat element in measuring the actual bearing pressure distribution, preferably at seat angles of above 45°, since the bearing pressure distribution required for evaluating the pelvic rotation(s) is shifted towards the back element if seat angles (particularly in the reclining position) are high. Preferably, the spatial positioning of the second bearing pressure sensor in relation to the first bearing pressure sensor can thereby be predetermined or, respectively, known so that an absolute and/or relative position determination of the bearing pressures via the first and second bearing pressure sensors is possible.

In an alternative embodiment variant, the bearing pressure sensor can extend beyond the seat element into the back element. In yet another alternative embodiment variant, the bearing pressure sensor can extend essentially completely across the seat element and the back element.

According to a further embodiment variant, the control unit can be programmed to issue instructions for the person to adopt the predetermined posture. By instructions being issued, the person can be helped, in particular, to adopt the correct (predetermined) posture or, respectively, to correctly adopt the predetermined posture. Such instructions can be, for example, instructions to straighten the upper body, to change the pelvic position or the like, whereby the entire spine can change as a unit before the actuating elements are adjusted.

According to one embodiment variant, the instructions can be issued to the person visually, aurally or audiovisually, for example. According to a further embodiment variant, the instructions can be issued to the person also in a tactile manner, in particular in the form of pressure, touch and/or vibrations.

According to one embodiment variant, the control unit can be connected to an external computer, smartphone or similar device, preferably wirelessly, whereby the predetermined posture and/or the instructions to adopt the predetermined posture can be issued on a display of the computer or smartphone. The person can thereby receive direct feedback in a simple and reliable manner as to whether their current posture matches the predetermined posture, and what measures can be taken to adapt the current posture to the predetermined posture. Preferably, measures in the form of movements or motion sequences, which facilitate an adjustment of the posture, can be indicated on the display of the computer or smartphone.

According to a further embodiment variant, a seat angle sensor connected to the control unit can be provided for measuring the seat angle between the seat element and the back element. In addition, the control unit can, in this case, furthermore be programmed to select the predetermined posture depending on the seat angle. By taking into account the seat angle between the seat element and the back element, the control unit can select an appropriate predetermined posture in a technically simple manner. The seat angle can thus clearly reflect as to whether an upright sitting posture, an inclined sitting posture or even a reclining posture is selected, for example. In this case, it can furthermore be prevented that a wrong or, respectively, inappropriate predetermined posture is selected, which does not correspond to the person's current or desired sitting or lying position. Selecting such a wrong posture would, in particular, force the person to adopt incorrect postures, resulting in detrimental muscle strain. In particular, the seat angle can be indicative of which target posture parameter matches the selected posture. For example, a correct pelvic rotation angle can be selected as a target posture parameter depending on the seat angle.

According to a further embodiment variant, an inclination sensor connected to the control unit can additionally be provided for measuring the inclination of the seat element. In addition to the seat angle, the inclination of the seating surface to the horizontal can also be used reliably for selecting a predetermined posture. In this case, the control unit can furthermore be programmed to select the predetermined posture depending on the inclination of the seating surface and/or the seat angle.

According to a further embodiment variant, the control unit can furthermore be programmed to select the predetermined posture depending on a previously measured actual posture. In addition to the previously measured actual posture, also the measured seat angle between the seat element and the back element (as previously described) can preferably be used for selecting the predetermined posture. A previously measured actual posture can serve, particularly in connection with the seat angle, as an indicator as to what posture the person is currently assuming at a given seat angle, or, respectively, as to which incorrect postures are thereby created. Based on the identified incorrect postures, a predetermined posture can thus be selected, which is supposed to compensate for the incorrect postures.

According to a preferred embodiment variant of the invention, the first actuating element on the back element can preferably be arranged in the area of the lumbar spine and in the transition zone to the thoracic spine and can thus function as an adjustable lumbar support in the back element. In any case, it is the purpose of the actuating element to give the person support so as to maintain the predetermined posture (in particular to maintain the pelvic position) so that, if possible, no or few fatigue effects will arise, which usually cause a return to an incorrect posture involving overstrain of the spinal structures. In particular, the first actuating element can thus prevent the formation of kyphosis of the spine.

According to a further embodiment variant of the invention, the seat element can have a second actuating element connected to the control unit for changing the contour of the seat element. In addition to the adaptability of the back element via the first actuating element, the seat element can also the adapted reliably to the predetermined posture by the second actuating element. A versatile device with an adjustable contour of the seat and back elements can be created in this way.

In this case, the second actuating element can be provided in the seat element preferably in the area of the thighs and/or knees and can thus provide a leg rest having a variable contour, e.g., for increasing the seating comfort in seating systems without the possibility of seat height adjustment, for example.

In one embodiment variant of the invention, the at least one bearing pressure sensor can be a surface sensor which is arranged in the area of the seating surface of the seat element. By arranging the surface sensor in the seating surface, preferably in the rear area, complete detection of the bearing pressures exerted by the pelvis, as well as by the person's coccyx and sacrum, can be accomplished by the surface sensor, regardless of how the person is precisely oriented relative to the surface sensor. The reliability of the device according to the invention can thus be further improved.

In this case, the surface sensor is preferably designed as a two-dimensional array of sensors which are selected from the group consisting of mechanical, electrical, pneumatic or hydraulic sensors. As a result, the position of the pelvis can be detected in every position of the person on the seat or lounger. By varying the number of sensors, the accuracy of the detection of sitting and bearing pressures by the sensors can be influenced. In doing so, a large number of sensors enable precise detection of the sitting and bearing pressures of the person's pelvis.

According to a preferred embodiment variant, the control unit can be programmed to run an iterative algorithm that maps the Mandelbrot set in order to limit the measuring range for the actual bearing pressure distribution on the bearing pressure sensor (in particular of the surface sensor). It has been shown that the area on a bearing pressure sensor in which the bearing pressure distributions of a person on a seating surface, which are relevant to seating systems, are found as a function of the seat angle can be mapped onto a Mandelbrot set. The parametrization of the base circle is thereby determined from three peak pressure ranges (2 ischial tuberosities, coccyx and sacrum, respectively) and, by contemplating the pressure-transmitting skeletal structures as a quasi-rigidly contiguous functional unit with a certain characteristic, a generalized coordinate (angle) representing the orientation of the pelvis on the sensor is calculated within the detecting area, whereby the assessment of sitting positions also becomes possible as soon as the pelvis is rotated into a sitting posture and a third pronounced peak pressure range is no longer detected within a large rotation angle range with a roughly constant ischial tuberosity distance. A more detailed description of the parametrization of the Mandelbrot set is provided in WO 2021/072461 A1.

In order to be able to narrow down the area of the surface sensor which detects sitting and bearing pressures, the computer unit runs an iterative algorithm which maps the Mandelbrot set using a recursive sequence z_n+1=z_n²+C, with an initial condition z₀=0. For this purpose, the surface sensor is perceived as a Gaussian plane in which the sitting and bearing pressures exerted by the person's pelvis are points C in the Gaussian plane. By inserting different points C into the recursive sequence, it can be ascertained which points C of the Gaussian plane belong to the Mandelbrot set and which do not. In this case, the Mandelbrot set includes those points for which the sequence remains limited, i.e., converges, i.e., increasingly approaches a limit value. For a point C in the Gaussian number plane with the coordinates C(0/0), a circular area detecting sitting and bearing pressures arises, since the sequence is reduced to z_n+1=z_n². At points C outside of this circular area, the numbers tend to infinity and the sequence is no longer limited. By mapping the Mandelbrot set by the recursive sequence, it is possible to map the three-dimensional structure of the person's pelvis two-dimensionally on a flat contact surface, for example on the bearing pressure sensor (surface sensor). In doing so, the two-dimensional structure of the pelvis essentially corresponds to the shape of a cardioid, which can be represented by the Mandelbrot set.

The two-dimensional cardioid shape of the pelvis is created by the rolling process of the latter on the flat contact surface. Starting from a first location of the pelvis, which corresponds to an upright sitting position of the person, the pelvis of this person is tilted forwards around the horizontal axis by 90° into a second location and then backwards into a third location. In order to reach the third location, the pelvis is tilted backwards around the horizontal axis by 90° relative to the first location of the pelvis or, respectively, by 180° relative to the second location of the pelvis. The third location corresponds to a horizontal dorsal position of the person. Starting from the horizontal dorsal position, the pelvis is rolled over the iliac crests on both sides, which corresponds to a mixed rotation of the pelvis or a pure rotation around the longitudinal axis in the reclining position. Thus, the shape of a cardioid is formed at the connection of all contact points on the flat contact surface. The cardioid thus corresponds to a two-dimensional representation of an outer contour of the person's three-dimensional pelvis. In this case, the sacral structure of the pelvis is depicted also two-dimensionally inside the cardioid.

Depending on the number of iterations, which determines the shape and magnitude of the area detecting sitting and bearing pressures and thus the shape and magnitude of the Mandelbrot set, the sitting and bearing pressures exerted by the person's pelvis on the surface sensor occur within said cardioid. Few iterations, for example two, result in a larger area detecting sitting and bearing pressures, in this case an elliptical area, whereas a large number of iterations produce a more limited, e.g., a cardioid-shaped, area detecting sitting and bearing pressures. For positioning the person's pelvis by means and methods known from the prior art, for example those of A 50386/2019, a higher number of iterations is to be preferred over a lower number. With as little as five iterations, a cardioid-shaped limited area detecting sitting and bearing pressures can be mapped, which is sufficient for positioning the pelvis by the above-mentioned means and methods. When a predetermined number is reached, the currently running iteration is interrupted.

If the cardioid-shaped area detecting sitting and bearing pressures has been detected using the iterative algorithm, a corresponding area for detecting the actual bearing pressure distribution on the bearing pressure sensor can be determined for each predetermined posture (at a specific seat angle).

According to one embodiment variant, the first and/or second actuating element can have, according to the invention, one or several air chambers with associated valves, the air chambers being connected to at least one pump and the control unit being designed for opening and closing the valves. By providing several air chambers, the contour of the back element can be adjusted in a particularly flexible and comfortable manner. In this case, the air chambers can preferably have a cushion-like shape and can be filled with air in such a way that the person will have a comfortable and not too hard sitting experience, but sufficient dimensional stability can still be guaranteed so that the person will be able to keep the intended posture for quite some time without any strong signs of fatigue.

According to one embodiment variant, the air chambers can at least partially overlap in the first and/or second actuating element. As a result of the overlap of the air chambers, i.e., the air chambers lying on top of each other in the direction of the contour of the back element, an actuating element can be created which enables particularly complex and flexibly adaptable contours on the back element.

According to a further embodiment variant, the control unit can be programmed to fill or, respectively, vacuum-seal the air chambers independently of each other by actuating the valves and the pump. Depending on the required contour in the back element, the control unit can therefore fill the air chambers individually with the respective valve being opened and, respectively, can close the valve after filling and can thus fix the filling of the air chamber. In this case, the at least one pump can also be connected to the control unit and can be controlled in such a way that the respective air chamber is filled with the valve being opened. In addition, the pump can also be designed for vacuum-sealing the air chamber with the valve being opened, thus reducing the filling of the air chamber. By selectively inflating or vacuuming-sealing the air chambers, the hardness of each air chamber can be individually adjusted and a particularly comfortable and versatile actuating element can thus be created.

In a further embodiment variant, the air chambers can comprise a loose, particulate filling material, which is freely displaceable in the filled state of the air chambers and is fixed in its position in the vacuum-sealed state of the air chambers. In this case, the particulate filling material can be a soft, but still dimensionally stable, preferably spherical, material, e.g., balls made of hard foam. In particular, the air chambers can thus be filled with so much filling material that the air chambers in the vacuumed-sealed state will have sufficient volume due to the filling material for changing the contour of the back element. In the air-filled state, the filling material is easily displaceable in the air chambers so that the air chambers can assume any desired shape without being forced. After the air chambers have been pre-filled, the person can, for example, imprint the respective desired shape on the air chambers by leaning on the back element, wherein this shape is fixed by vacuuming-sealing the air chambers. The air chambers can then retain the fixed shape until the next filling with air, and a stable and permanent shape of the actuating element can thus be guaranteed.

According to an alternative embodiment variant, the first and/or second actuating element can also have mechanically and/or hydraulically adjustable elements.

According to a further embodiment variant, the control unit can furthermore be programmed to actuate the first and/or second actuating element at predetermined time intervals after the contour of the back element has been adapted to the posture of the person in order to change and/or modulate the contour of the back element. For example, according to a further embodiment variant, a pump or, respectively, valves can thus be specifically actuated in such a way that the air pressure in air chambers is changed at predetermined time intervals. A possible breakdown of the posture-stabilizing muscles due to the supporting measures in case of a prolonged service life can be counteracted by changing or, respectively, modulating the contour of the back element by further stimulating or training the person's muscles.

According to a further embodiment variant, the control unit can be programmed to measure the actual bearing pressure distribution and to monitor the actual posture parameter during and/or after changing or, respectively, modulating the contour of the back element. For example, it can thus be detected as to whether the person can still keep the predetermined posture after changing or while modulating the contour of the back element, or whether it only varies within a certain neutral range (the defined rotation angle range). This measure constitutes a targeted mobilization measure.

According to a further embodiment variant, the control unit can be further programmed to change or, respectively, modulate the contour of the back element in a predetermined posture parameter range. If, for example, according to one embodiment variant, the target posture parameter is a pelvic rotation angle, the change or, respectively, the modulation of the contour can occur within a range of ±11.25° around the pelvic rotation angle as a posture parameter. In doing so, the pelvis is stimulated by changing or, respectively, modulating the contour of the back element in such a way that the pelvic rotation angle determined from the actual bearing pressure distribution deviates from the target value by a maximum of ±11.25°.

Furthermore, it is an object of the present invention to provide a method of adapting the contour of a back element to the posture of a person, which enables the contour to be adapted automatically without additional input from the person.

The invention achieves the object posed by a method according to claim 10.

In the method according to the invention, a person is accommodated in a sitting or lying posture on a seat element, which is connected to a back element at a seat angle, especially in a tiltable way. The following steps are now performed in the method, preferably in the specified order:

- a) selecting a predetermined posture and at least one characteristic target posture parameter allocated to the predetermined posture,
- b) measuring the actual bearing pressure distribution,
- c) determining an actual posture parameter from the actual bearing pressure distribution,
- d) comparing the actual posture parameter with the target posture parameter,
- e) repeating steps b)-d) until a match of the actual posture parameter with the target posture parameter is determined,
- f) if the actual posture parameter matches the target posture parameter: adapting the contour of the back element to the posture of the person.

In step a), a predetermined posture is first selected from a number of different possible physiologically correct postures which the person should keep while sitting or lying on the seat element. In this case, the predetermined posture is assigned at least one characteristic target posture parameter each, which matches the predetermined posture on the seat element.

As already discussed above, the target posture parameter can preferably be a pelvic rotation angle when the pelvis rotates about the transverse, sagittal or longitudinal axis.

In this case, the actual bearing pressure distribution thereby exerted by the person on the seat element is measured in step b) via a bearing pressure sensor provided in the seat element.

In step c), an actual posture parameter is then calculated from the measured actual bearing pressure distribution, with the actual posture parameter correlating with the selected target posture parameter, hence being comparable (e.g., actual and target pelvic rotation angles about the transverse axis of the pelvis).

By drawing a comparison between the actual posture parameter and the target posture parameter, it can thus be determined in step d) as to whether the person actually adopts the predetermined posture correctly.

If the correct adoption of the predetermined posture is not identified, i.e., the actual posture parameter does not match the target posture parameter, steps b) to d) are repeated until a match between the actual posture parameter and the target posture parameter is identified. In an alternative embodiment variant, steps b) to d) can also be performed continuously at predetermined time intervals until a match is identified.

As soon as a match is identified, i.e., the predetermined posture (characterized by the target posture parameter) has been adopted correctly by the person, the contour of the back element can be adapted to the posture of the person in step f). In doing so, the contour of the back element is adapted in particular in such a way that the person is assisted in keeping the correct predetermined posture.

The method according to the invention can thus ensure that the contour of the back element is always adapted to the posture of the person in such a way that said person can keep the physiologically correct (selected) posture for quite some time without any postural damage, or, respectively, muscle fatigue is prevented through appropriate support.

According to an embodiment variant of the method, the seat angle between the seat element and the back element is determined to this end prior to step a), and consequently the predetermined posture and the characteristic target posture parameter are selected in step a) depending on the seat angle. Based on the seat angle, the method can select a correct predetermined posture particularly reliably, since the seat angle clearly reflects as to whether there is an upright sitting posture, an inclined sitting posture or, for example, a reclining posture. The risk of selecting an incorrect or unappropriate predetermined posture can thus be significantly reduced, whereby the reliability of the method can be further increased.

Taking into account the seat angle between the seat element and the back element, the control unit can select a suitable predetermined posture in a technically simple manner. In this case, the seat angle can clearly reflect as to whether an upright sitting posture, an inclined sitting posture or even a reclining posture is selected. Then, in accordance with the seat angle, the characteristic target posture parameter associated with the selected posture can subsequently be selected. For example, according to a particular embodiment variant, the posture parameter can be a pelvic rotation angle and the target posture parameter can be selected as a target pelvic rotation angle depending on the seat angle.

In addition or as an alternative to the seat angle, according to a further embodiment variant of the method, the predetermined posture can be selected based on an inclination of the seat element.

In alternative embodiment variants, the predetermined posture can also be selected based on other alternative or additional parameters, such as an actual bearing pressure distribution of the person on the seat element, as measured before step a), historical data on the person's preferred postures and/or on known incorrect postures, or the like.

According to a preferred embodiment variant, between steps a) and b), an instruction can be issued for the user to adopt the predetermined posture. In this case, the predetermined posture can be displayed visually or issued acoustically to the user, preferably in addition or as an alternative. The instructions can thus be visual, aural or tactile instructions.

According to a further embodiment variant of the method, an iterative algorithm that maps the Mandelbrot set can be run to limit the measuring range of a surface sensor for measuring the actual bearing pressure distribution. For a more detailed explanation of the iterative algorithm, reference is made to the above comments on the device according to the invention.

In a further preferred embodiment variant of the method, in step f), several independent air chambers that can be shut off by valves can be pre-filled with a selected air pressure by opening the valves and can subsequently be fixed by closing the valves in order to adapt the contour of the back element.

In a further embodiment variant, a single air chamber that can be shut off by a valve can similarly be pre-filled with a selected air pressure by opening the valve and can subsequently be fixed by closing the valve in order to adapt the contour of the back element.

In this case, the air chambers can be continuously filled with a constant pressure or a constant flow rate using a pump with the valves being opened, while the person adopts the predetermined posture. In doing so, the person leans partially against the backrest and the air chambers in such a way that, in each case, a different amount of air escapes from the different air chambers. After the valves have been closed, the air chambers are thus filled with different pressures and jointly form the contour of the back element.

Preferably, the selected air pressure can be varied during the pre-filling of the air chambers according to a desired setting, with the selected air pressure corresponding to a degree of hardness of the air chambers.

According to a further embodiment variant of the method, the contour of the back element can be changed and/or modulated at predetermined time intervals after the contour of the back element has been adapted to the posture of the person. This change or modulation can, for example, consist in loosening the fixed contour of the back element and can thus encourage the person to use their muscles for stabilizing or, respectively, keeping the posture. According to a further embodiment variant, modulating the contour of the back element can also involve an act of over- or underfilling air chambers in order to stimulate the muscles.

According to a further embodiment variant of the method, the change or, respectively, modulation of the contour of the back element can occur in a predetermined range of the target posture parameter, as described above for the device.

Particularly preferably, the method according to the invention can be performed using a device according to any of claims 1 to 10. In this connection, the control unit is programmed in particular to perform the method according to the invention. In this regard, reference is made to the above comments on the device according to the invention.

The device according to the invention according to any of claims 1 to 10 can prove to be particularly advantageous in a piece of seating furniture with a seating surface and a backrest, comprising the device, with the seat element being integrated into the seating surface and the back element being integrated into the backrest.

Furthermore, the device according to the invention according to any of claims 1 to 10 can prove to be particularly advantageous in a seat cover for being placed on a piece of seating furniture, comprising the device.

SHORT DESCRIPTION OF THE FIGURES

Preferred embodiment variants of the invention are illustrated in further detail below with reference to the figures. Therein:

FIG. 1 shows a schematic view of a device for adapting the contour of the back element according to a first embodiment variant of the invention with a person in an upright sitting posture,

FIG. 2 shows a schematic view of a device for adapting the contour of the back element and the seat element according to a second embodiment variant of the invention with a person in an upright sitting posture,

FIG. 3 shows a schematic view of a device for adapting the contour of the back element and the seat element according to a third embodiment variant of the invention with a person in an upright sitting posture,

FIG. 4 shows a schematic view of the device of FIG. 1 with a person in an inclined sitting posture,

FIG. 5 shows a schematic view of the device of FIG. 1 with a person in a reclining posture,

FIG. 6a shows a first actual bearing pressure distribution of a person in an upright sitting posture,

FIG. 6b shows a second actual bearing pressure distribution of a person in an upright sitting posture,

FIG. 6c shows a third actual bearing pressure distribution of a person in a backwards inclined sitting posture,

FIG. 6d shows a fourth actual bearing pressure distribution of a person in a backwards inclined sitting posture,

FIG. 6e shows a fifth actual bearing pressure distribution of a person in a reclining posture, and

FIG. 6f shows a sixth actual bearing pressure distribution of a person in a reclining posture.

WAYS OF IMPLEMENTING THE INVENTION

FIG. 1 shows a schematic view of the device 100 according to the invention, on which a person 1 is positioned in an upright sitting posture. In this case, the device 100 comprises a back element 2 and a seat element 3, which are interconnected in a tiltable way and include a seat angle 4. The person 1 thereby places a load on the seat element 3 with their pelvis or, respectively, the two ischial tuberosities 21.

According to a further embodiment variant, which has not been depicted in further detail in the figures, the back element 2 can also be connected rigidly to the seat element 3 rather than being tiltable relative to it.

In the rear area of the seat element 3, a bearing pressure sensor 5 is provided which measures the actual bearing pressure distribution exerted by the person 1 on the seat element 3. The bearing pressure sensor 5 is preferably designed as a surface sensor or, respectively, as a surface pressure sensor, wherein the surface sensor can simultaneously measure the bearing pressure at different points and can thus determine the bearing pressure distribution directly in the plane of the seat element 3. In an alternative embodiment variant, the bearing pressure sensor 5 can also be distributed over the entire seat element 3, although this has not been depicted any further in the figures.

In addition, the back element 2, as shown in the embodiment variant of FIG. 1, comprises a second bearing pressure sensor 5a, which is arranged in the lower area of the back element 2 and essentially connects directly to the first bearing pressure sensor 5. The device 100 can thus enable complete detection of the bearing pressure distribution even in case of high seat angles 4, e.g., in an inclined sitting posture 20a or a reclining posture 20b, as illustrated in FIGS. 4 and 5.

In an alternative embodiment variant, which is not depicted either in the figures, the bearing pressure sensor can extend across the entire seat element 3 and across the entire back element 2.

In the back element 2, at least one first actuating element 6 is provided, which is designed for changing the contour 7 of the back element 2. In this case, the actuating element 6 is preferably arranged in the area 8 of the lumbar spine and in the transition zone to the thoracic spine of the person 1 so that the actuating element 6 constitutes a support, in particular in the form of a lumbar support, after the adaptation to the posture of the person 1 has occurred.

According to a first embodiment variant of the invention, the first actuating element 6 comprises two air chambers 9 which are connected to a pump 11 via fluid lines 10. In addition, in all fluid lines 10, one valve 12 is provided in each case, which can selectively separate or establish the connection between the respective air chamber 9 and the pump 11. When the valves 12 are closed, the air chambers 9 are closed and the trapped air cannot escape from the air chambers 9. By appropriately opening and closing the valves 12, the individual air chambers 9 can be filled with different pressures, whereby an arbitrarily adjustable actuating element 6 is obtained.

According to the invention, the air chambers 9 are filled with air. In alternative embodiment variants, the air chambers 9 can also be filled with other fluids, such as, for example, various gases or liquids. In this case, the air chambers 9 are designed for receiving any fluids.

In FIG. 2, a device 101 according to a second embodiment variant is shown. In this case, the first actuating element 6a has three air chambers 9a, which partially overlap each other. Again, as already described previously for FIG. 1, the air chambers 9a are connected, in this case, to a pump 11, in each case via fluid lines 10, with valves 12 always being provided in the fluid lines 10 between the pump 11 and the air chambers 9a.

In the seat element 3, the device 101 in FIG. 2 additionally comprises a second actuating element 6b, which is designed for changing the contour 7a of the seat element 3. The second actuating element 6b also has an air chamber 9b, which is connected to a pump 11a by means of a fluid line 10 via a valve 12. In this case, the pumps 11, 11a are designed for simultaneously filling and vacuum-sealing the air chambers 9a, 9b.

As indicated in FIG. 2, the air chambers 9a, 9b in the device 101 are filled with a loose, particulate filling material 13. In this case, the filling material 13 is freely displaceable when the air chambers 9a, 9b are filled with air, whereby the air chambers 9a, 9b can adapt particularly easily to the posture of the person 1. If the air chambers 9a, 9b are now vacuum-sealed, the air chambers 9a, 9b permanently retain their shape, which has been imprinted by the individual back or spine profile or, respectively, by the thigh, and can thus reliably adapt the contour 7 of the back element 2 and/or the contour 7a of the seat element 3 to the posture of the person 1.

Moreover, the features described above and below with reference to FIG. 1 apply mutatis mutandis to the device 101 according to the second embodiment variant, unless otherwise described.

In FIG. 3, a device 102 according to a third embodiment variant is shown. In this embodiment variant, the actuating element 6c only has a single air chamber 9c, with the actuating element 6c and the air chamber 9c being arranged essentially over the entire back element 2. In this case, the air chamber 9c is filled with a particulate filling material 13, as already described previously for the air chamber 9a in FIG. 2. By vacuuming-sealing the air chamber 9c by means of the pump 11, the filling material 13 can be fixed in its position and the contour 7 of the back element 2 can thus be adapted to the posture of the person.

With regard to the further features of FIG. 3, reference is made to the above description of FIGS. 1 and 2.

In an alternative embodiment variant, which, however, has not been depicted in any further detail in the figures, all air chambers 9, 9a, 9b, 9c are connected, in each case, to a separate pump 11, 11a via a valve 12. In this way, all air chambers 9, 9a, 9b, 9c can be filled simultaneously with different pressures or can be vacuumed-sealed independently of each other, which allows the actuating elements 6, 6a, 6b, 6c to be adjusted in a complex and versatile manner.

The device 100, 101, 102 according to the first, second and third embodiment variants in FIGS. 1 to 3 furthermore comprises a seat angle sensor 14 for measuring the seat angle 4 between the seat element 3 and the back element 2.

The device 100, 101, 102 comprises a control unit 50, which is connected to the pumps 11, 11a, the valves 12, the seat angle sensor 14 and the bearing pressure sensor 5, 5a via control lines 15. In an alternative embodiment variant, instead of the control lines 15, wireless connections can also exist between the control unit 50 and the pumps 11, 11a, the valves 12, the seat angle sensor 14 and the bearing pressure sensor 5, 5a.

According to a further embodiment variant, the device 100, 101, 102 can also comprise an inclination sensor connected to the control unit 50, which measures the inclination of the seat element 3 to the horizontal, which, however, has not been depicted in any further detail in the figures.

The control unit 50 is programmed to perform a method 200 of adapting the contour 7 of the back element 2 to the posture of the person 1. In one embodiment variant, the control unit 50 is thus programmed as follows:

- to select a predetermined posture and a characteristic target posture parameter matching the predetermined posture, in particular depending on the seat angle 4,
- to preferably issue instructions for adopting the selected predetermined posture,
- to determine an actual posture parameter from the actual bearing pressure distribution measured by the bearing pressure sensor 5 and to compare the determined actual posture parameter with the target posture parameter,
- if the actual posture parameter and the target posture parameter match, to actuate the actuating elements 6, 6a, 6c in such a way as to adapt the contour 7 of the back element 2 to the posture of the person 1.

In a further embodiment variant, the control unit 50 is furthermore programmed to run an iterative algorithm that maps the Mandelbrot set in order to limit the measuring range on the bearing pressure sensor 5, 5a (surface sensor) for measuring the actual bearing pressure distribution. By mapping the Mandelbrot set onto the measuring surface of the bearing pressure sensor 5, 5a, the measuring range can be reliably restricted to the measuring range which is relevant for determining the actual bearing pressure distribution. In this connection, reference is made to the statements in the introductory part of the above description.

The preferred embodiments of the device 100, 101, 102 are subsequently illustrated based on the method 200 according to the invention and FIGS. 1 to 5. In this case, the method 200 according to the invention can preferably be performed using a device 100, 101, 102. The control unit 50 of the device 100, 101, 102 is thus always programmed to perform the method 200 accordingly.

In the preferred embodiment variant, the method 200 according to the invention of adapting the contour 7 of the back element 2 to the posture of a person 1 thus comprises the following steps (in a specific order):

- a1) measuring the seat angle 4 between the seat element 3 and the back element 2; a) selecting a predetermined posture and at least one characteristic target posture parameter allocated to the predetermined posture, in particular depending on the seat angle 4;
- b1) issuing instructions for the person to adopt the predetermined posture;
- b) measuring the actual bearing pressure distribution;
- c) determining the actual posture parameter from the actual bearing pressure distribution;
- d) comparing the determined actual posture parameter with the selected target posture parameter,
- e) repeating steps b1)-d) until a match of the actual posture parameter with the target posture parameter is determined,
- f) if the actual posture parameter matches the target posture parameter: adapting the contour 7 of the back element 2 to the posture of the person 1.

In this case, steps a1) and b1) are optional and can optionally be omitted independently of each other, according to further embodiment variants.

The seat angle 4 is measured in step a1) using the seat angle sensor 14, and, in step b), the actual bearing pressure distribution is measured using the bearing pressure sensor 5.

The output of instructions to the person 1 in step b1) preferably occurs via a display 70 of a computer or a smartphone 60, which is preferably connected wirelessly to the control unit 50. The instructions can thereby be indicated aurally and/or visually so that the person 1 can easily correct any incorrect postures and can adopt the predetermined posture correctly.

As shown in FIGS. 1, 2 and 3, the person 1 adopts an essentially upright posture 20, which corresponds to a physiologically correct sitting posture. In this posture 20, only the ischial tuberosities 21 rest on the seat element 3; in this case, there is no contact of the coccyx 22 or sacrum 23 with the seat element 2, or, respectively, no significant pressure transfer to the bearing pressure sensor 5, 5a through the coccyx and sacrum 22, 23 can be detected.

In FIG. 4, the device 100 is again shown, with the person 1 adopting a backwards inclined sitting posture 20a. Therein, both the ischial tuberosities 21 and the coccyx and sacrum 22, 23 are in contact with the seat element 2.

Finally, the device 100 is shown in FIG. 5, with the person 1 adopting a reclining posture 20b. In this case, both the ischial tuberosities 21 and the coccyx 22 no longer have any contact with the seat element 2. The body section weight of the person 1 in the area of the pelvis is now supported exclusively by the sacrum 23.

In all postures 20, 20a, 20b, the pelvis of the person 1 is always aligned physiologically correctly, whereby the lumbar spine forms a lordosis in the area 8. In order to avoid pelvic rotations that are not adjusted to the seating system, the contour 7 of the back element 2 is adapted to the respective posture 20, 20a, 20b so that the actuating element 6, 6a, 6c can serve as a permanent support, can counteract fatigue of the posture-stabilizing muscles and can thus prevent damage associated with poor posture.

As shown in FIGS. 1 to 5, the postures 20, 20a, 20b match, in each case, the predetermined postures selected by the method 200. If there is a deviation from the respective predetermined posture, e.g., if the pelvis is rotated and the lumbar spine forms either a hyperlordosis or a kyphosis, an instruction to correct the posture can then be issued via the control unit 50 and via the smartphone 60 connected to the control unit 50 or via a computer or the like. If the posture 20, 20a, 20b is adopted correctly, the control unit 50 can additionally issue instructions to maintain the correct posture 20, 20a, 20b, while the actuating elements 6 are adapted to the person's posture.

In a preferred embodiment variant of the method 200, for adapting the contour 7 of the back element 2, the valves 12 to the air chambers 9 are opened in step f), and the air chambers 9 are pre-filled with a selected air pressure. This pre-filling can also take place with the valves 12 open throughout the entire method 200 until the posture has been adopted correctly and the valves 12 are finally closed for fixing the air chambers. The air pressure during pre-filling can be preset or adjusted according to a desired degree of hardness. For example, the degree of hardness can be adjusted by the person 1 during the method 200 via the smartphone 60 in connection with the control unit 50.

In FIGS. 6a to 6f, actual bearing pressure distributions 30, 31, 32, 33, 34, 35 are shown, which each are measured by the bearing pressure sensor 5 and each correlate with different postures 20, 20a, 20b of the person 1 on the device 100, 101, 102.

In this case, the bearing pressure distribution 30 in FIG. 6a corresponds to an upright posture 20, as it is illustrated in FIGS. 1-3. A pelvic rotation angle β about the transverse axis of approximately 0° can thereby be determined as the actual posture parameter. The bearing pressure distribution 30 is thus characterized by two peak sitting pressures 36a, 36b which are at a distance from the pelvic centre line 38 and correspond to the bearing pressures exerted by the ischial tuberosities 21. Bearing pressure from the coccyx or sacrum 22, 23 is not detected in this case.

In FIG. 6b, however, a bearing pressure distribution 31 of the same upright posture 20 as in FIG. 6a is shown, but with a pelvic rotation to be corrected. In addition to the peak sitting pressures 36c, 36d exerted by the ischial tuberosities 21, a peak sitting pressure 37a can also be identified from the actual bearing pressure distribution 31 which is exerted by the coccyx or sacrum 22, 23 and indicates the rotation of the pelvis deviating from the predetermined upright posture. The pelvic rotation angle β derivable from the bearing pressure distribution 31 is therefore not 0°, as specified by the target posture parameter, but approximately 25°. In the course of the method 200, instructions can now be issued for the person 1 to correctly adopt the predetermined posture or, respectively, to reduce the pelvic rotation angle β, or the actuating elements can be actuated appropriately for correction.

The bearing pressure distribution 32, as shown in FIG. 6c, corresponds to a backwards inclined sitting posture 20a, as it is illustrated in FIG. 4. In this case, the pelvic rotation angle β is approximately 32°. The bearing pressure distribution 32 shows peak sitting pressures 36e, 36f which are exerted by the ischial tuberosities 21, like previously the bearing pressure distribution 30 and 31. Moreover, a peak sitting pressure 37b exerted by the coccyx or sacrum 22, 23 is visible.

In FIG. 6d, a bearing pressure distribution 33 corresponding to a backwards inclined sitting posture with a pelvic rotation angle β of approximately 45° is in turn shown. The peak sitting pressures 36g, 36h emanating from the ischial tuberosities 21 are reduced in intensity compared to the bearing pressure distributions 31, 32 in FIGS. 6b and 6c and are shifted forward towards a higher pelvic rotation angle β. The peak sitting pressure 37c exerted by the coccyx or sacrum 22, 23, however, is located around the 45° point on the pelvic centre line 38.

In FIG. 6e, a bearing pressure distribution 34 is shown which corresponds to a flatly reclining posture 20b, as it is illustrated in FIG. 5. What is noticeable first of all is that the bearing pressure distribution 34 does not show any peak sitting pressures that are exerted by the ischial tuberosities 21. By contrast, a dominant peak sitting pressure 37d exerted by the person's sacrum 23 is visible. In this case, the pelvic rotation angle β is approximately 90°. Furthermore, it can be seen in FIG. 6e that, in addition to a pelvic rotation angle β about the transverse axis of the pelvis, a pelvic rotation angle γ about the sagittal axis of the body can also be identified. The pelvic rotation angle γ thereby manifests itself as a deviation of the peak sitting pressure 37d from the pelvic centre line 38.

Finally, in FIG. 6f, a bearing pressure distribution 35 is shown which corresponds to a flatly reclining posture of a person 1, with the lordotic curvature of the lumbar spine being eliminated progressively. This leads to further rotation of the pelvis, which ultimately manifests itself in a pelvic rotation angle β of over 90°. In the specific case, a peak bearing pressure 37e which is exerted by the sacrum 23 and is located approximately at the position of the pelvic rotation angle β of 101° can be seen in the bearing pressure distribution 35. In addition, a pelvic rotation angle γ can again be identified as a deviation of the peak bearing pressure 37e from the pelvic centre line 38. With a larger pelvic rotation angle γ, the pelvis is increasingly stressed.

The purely kinematic consideration of the pelvic and spinal structures (2 ischial tuberosities, coccyx and sacrum) as a functional unit during the transmission of contact force allows a generalized coordinate to be selected within a configuration space defined via the Mandelbrot set or, respectively, the geometric relationships derived therefrom in order to describe their change of position in all three body levels. In this case, the pelvic centre line 38 defines the pelvic rotation angle β in the bearing pressure distributions 30-35 of FIGS. 6a-6f as a generalized coordinate along a straight line on the bearing pressure sensor 5 or 5a. When a peak sitting pressure 37b exerted by the coccyx and sacrum 22, 23 is measured for the first time, as shown in FIG. 6c, the position of the 11.25° point of the pelvic rotation angle β can be found as half the distance between the peak sitting pressure 37b and a connecting line of the peak sitting pressures 36e and 36f. The individual position of the 11.25° point in relation to the peak sitting pressures of the ischial tuberosities, which remains geometrically constant over a pelvic rotation angle range β, thereby emerges apparently as an anatomical law, wherein deviations and, respectively, correction factors, for example depending on gender, age, weight, etc., can be taken into account. Thus, by determining the position of the 11.25° point and calculating the distance of the peak sitting pressures 36e and 36f at the point in time of detecting the peak sitting pressure 37b, the entire scaling of the pelvic rotation angle β along the pelvic centre line 38 can be calculated, with the 0° point being shifted by 11.25° towards a smaller pelvic rotation angle β. The length from 0° to 11.25° is thereby defined via the relationship 0.25×0.5×C, with the radius of the base circle C of the Mandelbrot set being calculated via twice the distance between the ischial tuberosities 21 (represented by the peak sitting pressures 36c, 36d) and representing a pelvic rotation angle β of 90° in total. As soon as the scaling is performed based on 3 peak pressure ranges, hence, depending on the pelvic rotation angle β, either all 3 ranges can be combined in a reliable manner (sitting postures that are inclined backwards), or 2 ranges (upright sitting positions) or only 1 range (lying positions) can be used for evaluating the actual bearing pressure distribution, especially since, for example, the degree of hardness and/or the installation position of a sensor can significantly influence the pressure transmission and detection, respectively.

According to an embodiment variant of the invention, the method 200 can include a further step of calibrating the actual posture parameter. If, in this case, the actual posture parameter is, for example, a pelvic rotation angle β, the calibration can be performed as described in the previous paragraph by identifying a backwards inclined posture 20a for the first time, measuring the peak sitting pressure 37a from the coccyx and sacrum for the first time, and inferring the 11.25° point therefrom.

According to a further embodiment variant of the device 100, 101, 102, the controller 50 can also be designed for performing the above-described steps.

Furthermore, in FIG. 1, a piece of seating furniture 300 with a seating surface 303 and a backrest 302 is shown, the piece of seating furniture 300 comprising the device 100. In this case, the seat element 3 is integrated into the seating surface 303 of the piece of seating furniture 300, and the back element 2 is integrated into the backrest 302.

According to FIG. 3, the device 102 is shown as a seat cover 400 which can be placed on a piece of seating furniture 500 without any structural changes.

DEVICE AND METHOD FOR ADAPTING THE CONTOUR OF A BACK ELEMENT TO THE POSTURE OF A PERSON

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