DEVICE FOR DETERMINING THE POSITION OF A PERSON'S PULSE

Description

[0001] The present invention relates to a device according to claim 1.

[0002] The pelvis acts as a positional regulator for the neutral alignment of the functional spine and lower extremities. Although the pelvis exhibits age- and sex-specific differences in length and angle, a generally applicable, uniform description of its positional load can be made. In seating systems, the person's pelvis is generally supported by the seat and backrest. The ischial tuberosities serve to bear the weight of the upper body and, in an ergonomically correct, essentially upright sitting position, can withstand high pressure, whereas the coccyx and sacrum remain essentially unloaded in this position.In a horizontal supine position, the spine supports the majority of the upper body weight, while the weight of the pelvic region rests on the sacrum. In this position, the pressure exerted on the sacrum by the person's weight is essentially at its maximum, and the coccyx remains largely unaffected. In an ergonomically correct prone position, the pubic bone bears the maximum share of this body weight.

[0003] People are often unaware of their own individual posture while standing, sitting, and lying down, and adopt positions that cause one-sided, painful muscle contractures. In the long term, this can lead to degenerative processes, including herniated discs, due to improper loading of the spinal and pelvic structures. Prolonged sitting, in particular, requires constant muscular effort, often in incorrect postures and without sufficient compensatory movements. This creates muscular imbalances and contributes to a variety of physical complaints. By adopting such an ergonomically incorrect position, especially an incorrect sitting position, the coccyx or sacrum can bear some of the person's weight, leading to an imbalance in the load distribution between the pelvis and spine, particularly in the sacroiliac joints, the transition zone between the pelvis and spine.Furthermore, this can lead to compression and strain of the entire spine, particularly in the lumbar region, because the often soft underlying structures and reduced muscle tone, in order to maintain an individually ergonomically correct sitting position, lead the person to adopt a hunched posture in a passive sitting position for extended periods. The cause of this is the positional pelvic tilt. This is particularly detrimental for people requiring care and / or wheelchair users, as they cannot correct their incorrect sitting position themselves due to their physical limitations and are dependent on assistance from others, such as nursing staff.Since the aforementioned individuals often do not feel pain, for example due to paraplegia or a neurodegenerative disease, or are unable to express pain, they are particularly at risk of suffering permanent damage from assuming an incorrect sitting position.

[0004] To prevent this and counteract potential spinal strain and the associated risks of long-term physical damage, seating systems with a recess in the coccyx area are known in the prior art. While these seating systems relieve pressure on the coccyx and its region, they do not counteract incorrect posture or pelvic rotation, particularly around the horizontal axis, because they do not detect changes in spinal curvature that can affect pelvic position. Other seating systems known in the prior art, such as modern car seats, use fluid-filled pressure elements with sensors in the lumbar spine and / or ischial tuberosity area, which can be inflated by a pump, to achieve an ergonomically correct sitting position.

[0005] Such a car seat is disclosed in US20170086588A1, which comprises an air chamber system with two laterally spaced air chamber elements integrated into the seat surface. These elements, when the seater is sitting unevenly, position the pelvis by balancing the ischial tuberosities through the addition or removal of air via a compressor. Contact pressure sensors are integrated into the air chamber elements to detect the seat pressure exerted by the user's ischial tuberosities on the seat surface. A controller evaluates the seat pressure and controls the compressor accordingly.

[0006] A disadvantage of this seating system is that it does not precisely capture the individual position of the pelvis, but only determines the pressure exerted by the ischial tuberosities on the air chamber elements. This limits the system to horizontally compensating for the ischial tuberosities by rotating the pelvis around the sagittal axis. If the user adopts an incorrect sitting position, an over-inflated air chamber element can, for example, cause changes in spinal curvature, potentially leading to persistent hyperextension of the lumbar spine due to the incorrect pelvic rotation around the horizontal axis caused by the user's posture.Conversely, an insufficiently inflated pressure element can lead to a rounded back with a resulting posterior pelvic tilt, which brings with it the disadvantages already mentioned above, in particular the strain on the coccyx or sacrum bearing part of the person's weight in an upright sitting position. This muscular hyperextension or compression of the spine with unilateral abnormal stress on the intervertebral discs due to positional incorrect pelvic tilt cannot be addressed by the aforementioned state-of-the-art seating system, thus making subsequent physical damage in the thoracic and cervical spine regions adjacent to the lumbar spine unavoidable.

[0007] From the prior art (EP 3 011 896 A1, EP 1 093 755 A1, JP 2003 111646 A, US 2005 / 137462 A1), systems for monitoring a person's sitting posture using pressure sensors embedded in a chair or devices for measuring the pressure exerted on a person while lying down are also known. However, such systems or devices are not suitable for determining the position of a person's pelvis.

[0008] The applicant's earlier patent application A 50386 / 2019, which was not yet published at the time of this patent application, discloses a device for positioning a person's body, comprising actuators and sensors arranged on a seat element and a back element. This earlier patent application describes the rolling process of the person during the transition from an upright to a horizontal lying position, whereby the person's pelvis is positioned by linear actuator movements through rotations around the sagittal, horizontal, and longitudinal axes. The position of the pelvis is determined only indirectly, by positioning the person's pelvis once a predetermined difference in seating and / or pressure is reached. This does not allow for a precise determination of the pelvic position. To counteract an incorrect sitting position, it is therefore necessary to determine the position of the person's pelvis, i.e.,to determine the inclination and rotation of the pelvis around the person's body axes, precisely and for every position of the person on a sitting or lying system.

[0009] The object of the present invention is to provide a device for determining the position of a person's pelvis, which can be integrated into an existing seating or lying system and which avoids the aforementioned disadvantages of the prior art.

[0010] The present invention solves the stated problems by providing a device for determining the position of a person's pelvis with the features of claim 1.

[0011] In another aspect, the invention provides a computer program product which includes instructions which, when the program is executed by the computer unit, cause it to perform the steps of claim 1.

[0012] In another aspect, the invention provides a computer-readable data carrier on which the computer program product is stored.

[0013] Advantageous embodiments of the invention are described in the dependent claims, the description and the drawings.

[0014] The present invention provides a device wherein the evaluation unit is configured to perform the following steps: receiving and evaluating measurement signals from the pressure transmission elements, determining a first characteristic pressure distribution in which the first pressure transmission element is subjected to at least a part of the coccyx pressure during a rotation of the person's pelvis about its horizontal axis, or the first pressure transmission element is subjected to at least a part of the pubic bone pressure, and determining a second characteristic pressure distribution in which the coccyx pressure exerted on the first pressure transmission element exhibits a sudden drop and the sacrum pressure exerted on the second pressure transmission element exhibits a sudden increase.

[0015] By determining the characteristic pressure distributions mentioned above, the position of the pelvis relative to the person's horizontal axis can be precisely determined. For this purpose, the person whose pelvic position is to be determined must be pre-positioned on the seating or lying system, or, in the case of persons requiring care, by a third party, according to the arrangement of the pressure transmission elements on the seating system. After determining the characteristic pressure distribution, the person's pelvis can then be positioned using state-of-the-art means and methods so that an ergonomically correct position of the pelvis, allowing for the continued neutral alignment of the spine in any position, especially when tilted around the person's horizontal axis, can be maintained on the seating system.The aforementioned physical complaints, such as unilateral painful muscle contractures or degenerative changes in the spine, can be reduced or even completely avoided because the functional spine is individually and ergonomically aligned in relation to the pelvis. Furthermore, the person sitting on the seating system can be positioned and supported according to their anatomy, and this neutral alignment of the functional spine can be maintained even during rotations around the sagittal or longitudinal axis.

[0016] The possibility of integrating the present invention into an existing seating system or using it as a seat cushion on a chair or bed opens up a multitude of application possibilities, and the device is not limited to the following examples. The device could, for instance, be integrated into the following: office chairs, wheelchairs, vehicle seats, child restraint systems, exercise equipment, treatment couches, mattresses, and / or used in rehabilitation and therapy, particularly in standing beds, standing boards, and / or operating tables.The integration of the present invention into operating tables is particularly useful for procedures performed in the prone or supine position, as these are often carried out with inclined operating tables. This can lead to undesirable displacement of the person on the operating table or to mispositioning of the pelvis in relation to the spinal alignment, forcing the spine, especially in the lumbar region, into a compressed or extended position. A procedure with such a pelvic position can lead to a multitude of problems. The present invention can detect a deviation from the neutral, position-related position of the pelvis by sensing changes in seating and pressure between the first and second pressure transmission elements and counteract this position using the means and methods mentioned above.This allows the neutral, positional alignment of the pelvis to be restored and maintained. During surgery, which typically takes place on flat operating tables, the procedure can thus be performed with the body in optimal positioning, minimizing or even eliminating potential surgical risks and the sometimes very painful consequences of prolonged incorrect positioning, particularly through lumbar spine support tailored to the pelvic position.

[0017] According to a preferred embodiment of the device for determining the position of a person's pelvis, the first pressure transmission element and the second pressure transmission element are arranged at a substantially obtuse angle to each other. This has the advantage that the first and second characteristic pressure distributions can be determined even during a change in the inclination of the person's upper body, i.e., during a rolling motion of their pelvis from a substantially upright sitting position to a substantially horizontal lying position.

[0018] According to a preferred embodiment of the device for determining the position of a person's pelvis, the computer unit is further configured to periodically evaluate the measurement signals transmitted to the computer unit by the pressure transmission elements at a predetermined time interval. This allows the position of the pelvis to be monitored continuously, for example every second, and prevents incorrect positioning of a person requiring care by, for example, untrained personnel.

[0019] According to a preferred embodiment of the device for determining the position of a person's pelvis, the evaluation unit is a membrane unit comprising a membrane and connected to the pressure transmission elements via channels. This membrane unit includes a sensor arranged on the membrane and a processing unit designed to evaluate a sensor signal output by the sensor. The sitting and bearing pressures exerted by the person's pelvis on the pressure transmission elements cause a redistribution of the fluid contained within these elements. The membrane unit can convert this redistribution into a sensor signal, preferably an electrical sensor signal, that can be evaluated by the processing unit. This offers the advantage that the device can react quickly and reliably to a change in position or a deviation of the pelvis from its neutral, position-related position.

[0020] According to a further embodiment of the device for determining the position of a person's pelvis, the device comprises a third pressure transmission element and a fourth pressure transmission element, each arranged next to the second pressure transmission element and designed to absorb the pressure exerted by the person's iliac crests. This makes it possible to determine the position of the person's pelvis during rotation around its longitudinal axis, which is particularly advantageous for detecting micro- and macro-positioning in pressure ulcer prevention. These positions result in a shift of the body's center of gravity, at least in certain sections, thereby relieving pressure on specific areas of the body.A well-known positioning technique is the 30-degree incline, which, starting from a essentially horizontal supine position, is generally achieved with the aid of two large cushions and places weight on the right or left buttock or body side. Integrated into a seating or lying system of the aforementioned type, the device can detect the aforementioned shift in the body's center of gravity in the pelvic region and determine the position of the pelvis in a lateral position and, with additional rotation of the person around their longitudinal axis, also in a prone position.

[0021] According to a further embodiment of the device for determining the position of a person's pelvis, the device comprises a fifth pressure transmission element and a sixth pressure transmission element, each arranged next to the first pressure transmission element and designed to absorb the pressure exerted by the person's ischial tuberosities while sitting. The person's ischial tuberosities are spaced at a predetermined distance from one another and define an ischial tuberosity level which, when the person has assumed an ergonomically correct sitting position, is horizontally balanced around the sagittal axis. For a variety of reasons, such as prolonged sitting or physical impairments, one of the two ischial tuberosities may be subjected to greater pressure, leading to an unbalanced ischial tuberosity level and, in the long term, being detrimental to the pelvic and spinal structure, particularly the sacroiliac joints.The additional fifth and sixth pressure transmission elements allow the device to detect asymmetrical pressure distribution on the ischial tuberosities and, by calculating the difference between the pressures of the fifth and sixth elements, also determine the position of the pelvis relative to the sagittal axis. This enables the device to determine the position of the pelvis in relation to all three body planes, thus precisely and universally characterizing an ergonomically correct load distribution for any position of the person, i.e., sitting and lying, on a seating or lying system.

[0022] This embodiment of the invention allows the device to determine not only the position of the pelvis relative to the person's horizontal axis, but also the position of the pelvis relative to the sagittal and longitudinal axes. The information about the pelvic position can then be used by a seating system known in the prior art to correct the aforementioned asymmetrical seating and pressure load, or to perform micro- or macro-positioning adjustments.

[0023] According to a further embodiment of the device for determining the position of a person's pelvis, the device comprises an array with a plurality of pressure transmission elements, which is configured to detect the sitting and support pressures of the person's pelvis in any position of the person on the device. This has the advantage that the aforementioned step of pre-positioning the person on a seating system can be omitted, since in this embodiment not only the position but also the location of the pelvis on the seating system can be determined.

[0024] According to a preferred embodiment of the device for determining the position of a person's pelvis, the sensor is selected from the group consisting of mechanical, electrical, pneumatic, or hydraulic sensors. This makes it possible to detect the sitting and / or support pressures exerted by the person's pelvis using a variety of sensors. For example, mechanical sensors such as strain gauges or accelerometers can be used to detect the sitting and / or support pressures. When strain gauges are used, the need for a diaphragm unit is eliminated, and the sensor signal output by the sensor can then be directly evaluated by the evaluation unit, e.g., a computer. The term "sensors" is not limited to the examples mentioned above.

[0025] According to a preferred embodiment of the device for determining the position of a person's pelvis, the device includes warning means that alert the person when the first characteristic pressure distribution and / or the second characteristic pressure distribution has been determined. The warning means is selected from the group consisting of visual, acoustic, or haptic warning means. This enables individuals who have assumed an ergonomically incorrect sitting or lying position to be made aware of their incorrect posture and thus develop greater awareness of their body position. Regular reminders of an incorrect sitting or lying position can therefore help prevent physical injuries of the type mentioned above.In the case of people requiring care, the use of a warning device has the advantage that caregivers can be made aware of ergonomically poor and / or incorrect positioning of the people requiring care, which allows the interval of checks by a caregiver to be extended.

[0026] The invention will now be explained in more detail with reference to the drawings and by means of non-restrictive exemplary embodiments. Fig. 1a Figure 1 shows a schematic representation of the invention with a person sitting on an adjustable seating system in an ergonomically correct upright sitting position. Fig. 1b Figure 1 shows a schematic representation of the invention of a person located in an inclined position on the adjustable seating system, whose coccyx exerts a seating pressure on a first pressure element. Fig. 1c Figure 1 shows a schematic representation of the invention with a person located in an inclined position on the adjustable seating system, whose sacrum exerts a pressure on a second pressure element. Fig. 1d Figure 1 shows a schematic representation of the invention with a person lying in a horizontal position on the adjustable seating system, whose sacrum exerts a pressure on the second pressure element. Fig. 2 Figure 1 shows a diagram in which pressure profiles of the seat and support pressures exerted on the adjustable seating system during a rotation of the person's pelvis around the horizontal axis are shown, and markings are shown that illustrate a first characteristic pressure distribution and a second characteristic pressure distribution according to claim 1 of the invention. Fig. 3 shows a preferred embodiment of an evaluation unit. Fig. 4 shows a perspective view of a seating system with pressure transmission elements and the evaluation unit arranged on it. Fig. 3 according to a preferred embodiment of the invention. Fig. 5 shows a perspective view of a seating system with pressure transmission elements and the evaluation unit arranged on it. Fig. 3 according to a further embodiment of the invention. Fig. 6 shows a perspective view of a seating system with pressure transmission elements and the evaluation unit arranged on it. Fig. 3 according to a further embodiment of the invention.

[0027] The following refers to the Fig. 1a bis 1d Reference is made to the figures, which show a person 10 in an upright, an inclined and a horizontally lying position on an adjustable seating system 40 with a seat element 41 and a back element 42 in which the device 100 according to the invention is integrated. The device 100 can also be integrated into a reclining system, not shown, or into a support, also not shown, and is not limited to the one shown in the Fig. 1a bis 1d The depicted seating system 40 is limited. The device 100 is designed to accommodate the person 10 and comprises at least one first pressure transmission element 21 designed to receive a seating pressure or bearing pressure exerted by the coccyx 51 or pubic bone of the person 10, and at least one second pressure transmission element 22 designed to receive a bearing pressure exerted by the sacrum 52 of the person. As the Fig. 1b bis 1d As shown, the first pressure transmission element 21 and the second pressure transmission element 22 are arranged essentially at an obtuse angle to each other. The first pressure transmission element 21 is located centrally in a rear third of the seat element 41, facing the back element 42, and the second pressure transmission element 22 is also located centrally in a lower third of the back element 42, facing the seat element 41. Preferably, fluid-filled, very shallow chambers are used as pressure transmission elements 21, 22, wherein the chambers preferably have a shape at least partially adapted to the pelvis 50 of the person 10. This allows for higher sensitivity of the pressure transmission elements 21, 22, which enables precise detection of changes in seating and support pressure. In particular, even slight shifts in the body's center of gravity can be detected.The term fluid refers to any liquid or gas suitable for transmitting seat and support pressures. For example, water or air can be used as a fluid. The pressure transmission elements 21, 22 can also be simple strain gauges, such as metallic foil strain gauges, which undergo measurable changes in shape or length depending on the magnitude of the seat and support pressures. For improved seat and support pressure measurement, the pressure transmission elements 21, 22 are visibly arranged on the upper surface of the seat element 41, i.e., on the seat surface of the seat element 41, or on the upper surface of the back element 42, respectively. Alternatively, the pressure transmission elements 21, 22 can be invisibly embedded in the seat element 41 and / or in the backrest 42 of the seating system 40.

[0028] The Fig. 1a bis 1d show individual positions of person 10 during a rotation of this person around the horizontal axis, whereby the Fig. 1a the person is positioned on a seating system 40 in an ergonomically correct upright sitting position and Fig. 1d Person 10 is shown in an ergonomically correct horizontal lying position after the rotation has ended. Arrows in the Fig. 1b bis 1d represent the sitting and bearing pressures exerted by the pelvis 50 during the aforementioned rotation, where F1 illustrates the sitting pressure exerted by the ischial tuberosities, F2 the sitting pressure exerted by the coccyx, and F3 the bearing pressure exerted by the sacrum.

[0029] As in Fig. 1a As can be seen, in an ergonomically correct upright sitting position, the ischial tuberosities 53 bear the majority of the upper body weight of person 10, with smaller portions of the weight force also being absorbed by the person's lower extremities (not shown). In this sitting position, the coccyx 51 is unloaded and has a distance A to the seat surface of the seat element 41 of the seat system 40.

[0030] When person 10 rotates by an angle α, Fig. 1b In this position, the distance A, i.e., the distance from the coccyx 51 of person 10 to the seat surface of the seating system 41, decreases and is essentially zero. As a result, the coccyx 51 assumes a portion of the weight force and, in addition to the ischial tuberosities 53, exerts a seating pressure on the seat element 41, which is detected by the first pressure transmission element 21. This position corresponds to a tilt of the pelvis 50 of person 10 of essentially 10° about the horizontal axis.

[0031] Starting from this position, the weight distribution of person 10 shifts during further rotation such that the pressure exerted by the ischial tuberosities 53 on the seat element 41 is reduced or becomes zero, and the coccyx 51 and the sacrum 52 absorb the majority of the weight force. This position is in Figur 1c depicted and corresponds to a tilting of the pelvis 50 essentially 45° around the horizontal axis of person 10. The first pressure transmission element 21 detects the sitting pressure of the coccyx 51 and the second pressure transmission element 22 detects the bearing pressure of the sacrum 52 of person 10.

[0032] When person 10 is further transferred into a substantially horizontal lying position, Fig. 1d The weight force components shift such that, in this position, the sacrum 52 of person 10 exerts a maximum bearing pressure on the second pressure transmission element 22. As can be seen from the distance A, in this position the coccyx 51 exerts no bearing pressure on the first pressure transmission element 21.

[0033] The device 100 according to the invention comprises, in addition to the pressure transmission elements 21, 22 already mentioned, an evaluation unit 30 preferably connected to the pressure transmission elements 21, 22 via channels, wherein the evaluation unit 30 is configured to receive and evaluate measurement signals from the pressure transmission elements 21, 22. The measurement signal is a physical quantity such as pressure, electric current, or electric voltage and depends on the type of pressure transmission elements 21, 22 used. In the preferred embodiment mentioned above, in which fluid-filled chambers are used as pressure transmission elements 21, 22, the measurement signal is a pressure signal which is transmitted to the evaluation unit 30 via the channels.

[0034] Fig. 2 Diagram 60, with measurement series 61, 62, 63, and 64, shows the pressure profiles of the sitting and bearing pressures exerted on the aforementioned seating system 40 during the rotation of the pelvis 50 of person 10 described above. The scale of the ordinate of diagram 60 is shown in a normalized form, where 0 represents no sitting or bearing pressure and 1 represents maximum sitting or bearing pressure. Measurement series 61 shows the pressure profile of the sitting pressures exerted by the ischial tuberosities 53, measurement series 62 shows the pressure profile of the sitting pressure exerted by the coccyx 51, measurement series 63 shows the pressure profile of the bearing pressure exerted by the sacrum, and measurement series 64 shows the pressure profile of the bearing pressures exerted by the iliac crests 54.

[0035] The evaluation unit 30 is further configured to determine a first characteristic pressure distribution 65, in which the first pressure transmission element 21 is subjected for the first time to at least a part of the sitting pressure on the coccyx 51 or the first pressure transmission element 21 to at least a part of the bearing pressure on the pubic bone during a rotation of the pelvis 50 of person 10 about its horizontal axis. The first characteristic pressure distribution 65, in which the coccyx 51 of person 10 is subjected for the first time to at least a part of the sitting pressure, is in Fig. 2 This is shown when the pelvis is tilted 50 by 15° about the horizontal axis. Depending on the compliance of a substructure, for example, the seat surface of the seat element 41 of the seat system 40 and / or due to support of the spine 55 on the back element 42 and / or pathological changes of the coccyx 51, the coccyx 51 can already be subjected to pressure when the pelvis is tilted 50 by essentially 10° about the horizontal axis. In the prone position, the pubic bone of person 10 exerts pressure corresponding to the bearing pressure of the sacrum 52 of person 10 in the supine position, as shown in measurement series 63. Fig. 2 , exerts a pressure on the first pressure transmission element 21.

[0036] The evaluation unit 30 is further configured to determine a second characteristic pressure distribution 66, in which the seating pressure exerted on the first pressure transmission element 21 by the coccyx 51 exhibits a sudden drop, and the bearing pressure exerted on the second pressure transmission element 22 by the sacrum 52 exhibits a sudden increase. This second characteristic pressure distribution 66 is in Figur 2 shown.

[0037] The evaluation and reception of the measurement signals from the pressure transmission elements 21, 22, as well as the determination of the first characteristic pressure distribution 65 and the second characteristic pressure distribution 66, is implemented by a computer program. This program includes commands that, when executed by the evaluation unit 30, cause it to perform the aforementioned steps. The computer program is stored on a computer-readable data carrier.

[0038] Preferably, the characteristic pressure distributions 65, 66 are determined by the evaluation unit 30 by measuring the pressure differences of the sitting and bearing pressures exerted by the pelvis 50, coccyx 51, and sacrum 52 of person 10 on the pressure transmission elements 21, 22. However, the characteristic pressure distributions 65, 66 can also be determined via pattern recognition by comparing the sitting and bearing pressures with a predefined pressure pattern.

[0039] The Fig. 3 Figure 1 shows a preferred embodiment of the evaluation unit 30. Accordingly, the evaluation unit 30 is a membrane unit 37 comprising a membrane 31 and connected to the pressure transmission elements 21, 22 via channels (not shown). The membrane unit preferably evaluates the measurement signals transmitted to the evaluation unit 30 from the pressure transmission elements 21, 22 periodically at a predetermined time interval. For example, the measurement signals can be evaluated every second to enable reliable position detection of the pelvis 50 of person 10. The membrane 31 exhibits linear-elastic behavior and divides the membrane unit 37 into two chambers 32, 33, with a first chamber 32 having a pressure p1 and a second chamber 33 having a pressure p2. The chambers 32, 33 each also have an opening 35 on which the channels are arranged.The membrane unit 37 also includes a sensor 34 arranged on the membrane 31 and a computer unit, which is not shown. The sensor 34 is preferably arranged centrally on the membrane 31. The sitting and support pressures exerted by the coccyx 51 and the sacrum 52 of the person 10 on the seat element 41 and the back element 42 of the seating system 40 cause a redistribution of the fluid contained in the pressure transmission elements 21, 22, thereby generating a pressure difference in the chambers 32, 33, which leads to a planar membrane deflection 36. The sensor 34 arranged on the membrane 31 is preferably a sensor selected from the group consisting of mechanical, electrical, pneumatic, or hydraulic sensors, but in particular an accelerometer. By detecting a change in velocity, the accelerometer can detect the membrane deflection 36 and transmit a corresponding sensor signal to the computer unit.The computer unit then evaluates the sensor signal, which is preferably directly related to the membrane deflection 36. If the first pressure transmission element 21 is connected to the first chamber 32 and the second pressure transmission element 22 to the second chamber 33 of the membrane unit 37, a pressure level of p1 > p2 prevails in the first characteristic pressure distribution 65. If the sacrum 52 of person 10 exerts a greater contact pressure compared to the contact pressure exerted by the coccyx 51 while sitting, as is the case in the second characteristic pressure distribution 66, a pressure level of p2 > p1 is reached. If the coccyx 51 exerts the same contact pressure on the first pressure transmission element 21 as the sacrum 52 exerts on the second pressure transmission element 22, p1 = p2 and no membrane deflection occurs.This also corresponds to a load-free state of the pressure transmission elements 21, 22, i.e., the pressure transmission elements 21, 22 are not subjected to any seating and / or contact pressure. The accelerometer is preferably integrated into a computer unit (not shown). For example, a processor can be arranged on the membrane 31, which includes a corresponding accelerometer and evaluates the sensor signals from the accelerometer.

[0040] Figur 4 Figure 1 schematically shows a perspective view of the preferred embodiment of the invention. The membrane unit 37 is preferably arranged in the area of ​​the pressure transmission elements 21, 22 and preferably integrated invisibly into the back element 42 of the seat system 40. However, the membrane unit 37 can also be used independently of the seat system 40, in which case the length of the channels connecting the membrane unit 37 to the pressure transmission elements 21, 22 (not shown in this figure) can be significantly extended. The planar deflection 36 of the sensor 34, arranged here by way of example, in the membrane unit 37 occurs in the frontal plane in a longitudinal direction.

[0041] In a further embodiment, the device 100 according to the invention can comprise a third pressure transmission element 23 and a fourth pressure transmission element 24, as shown in Fig. 5 , which are each arranged next to the second pressure transmission element 22 and are designed to absorb the contact pressures exerted by the iliac crests 54 of person 10. These additional pressure transmission elements 23, 24 have essentially the same shape as the first pressure transmission element 21 and the second pressure transmission element 22 and are preferably also designed as fluid-filled chambers. The third pressure transmission element 23 and the fourth pressure transmission element 24 allow the membrane to be deflected not only longitudinally but also horizontally. A membrane deflection in the horizontal direction corresponds to a rotation of the pelvis 50 about the longitudinal axis of person 10. For this purpose, the membrane unit 37 comprises a second membrane, which is not shown in the figures, arranged such that it divides the membrane unit 37 into two additional chambers, also not shown, i.e.,The system is divided into a total of four chambers. The accelerometer is preferably located at the intersection point of the first and second membranes and detects both the planar membrane deflection in the longitudinal and horizontal directions.

[0042] In a further embodiment of the invention, illustrated in Fig. 6 The device 100 comprises a fifth pressure transmission element 25 and a sixth pressure transmission element 26, each arranged next to the first pressure transmission element 21 and designed to receive the contact pressures exerted by the ischial tuberosities 53 of person 10. The fifth pressure transmission element 25 and the sixth pressure transmission element 26 have essentially the same shape as the first pressure transmission element 21 and the second pressure transmission element 22 and are preferably also designed as fluid-filled chambers. In this embodiment, the membrane unit 37 is designed such that a membrane deflection occurs in both the longitudinal and horizontal directions. During sitting, the membrane experiences, due to the maximum sitting pressures exerted by the ischial tuberosities 53 on the fifth pressure transmission element 25 and the sixth pressure transmission element 26, as shown in Fig. 2, a maximum membrane deflection. This allows the upper body weight force of person 10 to be determined.

[0043] In this embodiment and the previously mentioned embodiment of the invention, the one with four pressure transmission elements 21, 22, 23, 24, the position of the pelvis 50 of person 10 can also be detected during mixed movements. Mixed movements can, for example, be movements of person 10 that occur simultaneously around the horizontal axis and the sagittal axis. This movement can occur, for example, when the ischial tuberosities 53 are subjected to asymmetrical loads and, at the same time, the pelvis 50 of person 10 rotates around its horizontal axis. The membrane deflection occurs in both the longitudinal and horizontal directions. A membrane deflection in the sagittal direction caused by the sitting and bearing pressures on the pelvis 50 is blocked by the above-described design of the membrane unit 37.Changes in the sensor signal in this plane are due to changes in the position of the seat element 41 of the seating system 40, which in turn allows conclusions to be drawn about the corresponding change in the position of the back element 42. Rotations of the seating system 40 around the longitudinal axis, corresponding to a lateral tilt of the seat element 41, and around the horizontal axis, corresponding to an upward or downward tilt of the seat element 41, can be determined. Using a force triangle calculation, the evaluation unit 30 can calculate the resulting maximum seating and / or support pressure. From this, the device can determine the seating and / or support pressure components of the pelvis, thus enabling the determination of the pelvic position 50 even in the case of a slight misalignment.

[0044] In an embodiment of the invention not shown in the figures, the device 100 comprises an array with a plurality of pressure transmission elements configured to detect the seat and support pressures of the pelvis 50 of person 10 in any position of person 10 on the device 100. The array with a plurality of pressure transmission elements can be integrated into the seat element 41, the back element 42, or both, i.e., into the seat element 41 and the back element 42. This eliminates the need to pre-position person 10 on the seat system 40.

[0045] In an embodiment not shown in the figures, the device 100 includes a warning device that warns the person 10 when the first characteristic pressure distribution 65 and / or the second characteristic pressure distribution 66 has been determined. If the first characteristic pressure distribution 65 and / or the second characteristic pressure distribution 66, i.e., an ergonomically incorrect sitting or lying position, has been determined by the evaluation unit 30, then, for example, acoustic signals in the form of a tone emitted by a loudspeaker or optical signals in the form of a warning light emitted by a warning lamp can warn the person 10. The warning devices can be integrated into / arranged on / in the seating system 40 or be located near the seating system 40, separate from it. The warning devices are selected from the group consisting of optical, acoustic, or haptic warning devices.

[0046] According to the embodiment described above with surface sensors, a rotation of the pelvis about the horizontal axis of approximately 45° results in the angle essential to the invention at which the weight force components of the person are transferred from the coccyx and ischial tuberosities to the sacrum on the seat element. This angle essential to the invention also depends on the weight of the individual and the firmness of the seat element. Accordingly, this angle essential to the invention can lie within a range that begins at 11°, at which the coccyx begins to exert pressure on the seat element, and ends at 56°, at which the ischial tuberosities relieve the pressure on the seat element. The angle essential to the invention can therefore be, for example, 35°, 40°, 43°, 45°, 47°, 50°, 53°, or 56°.

[0047] According to a further embodiment with a particularly soft seat cushion, the angular range described above for surface sensors, with an essential angle of at least 11°, does not represent the relevant limit. With a particularly soft seat cushion, the pressure of the coccyx can actually be measured even in an upright sitting position, i.e., at an essential angle of 0°, and the pressure of the ischial tuberosities can be measured in a lying position, i.e., at an essential angle of 90°. Therefore, for particularly soft seat cushions, the angular range of the essential angle should be set at 0° to 90°.

Claims

1. Device (100) for determining a position of the pelvis (50) of a person (10), which device (100) is designed to receive the person (10), comprising at least one first pressure transmission element (21) designed to receive a sitting pressure or support pressure exerted by the coccyx (51) or pubic bone of the person (10) and at least one second pressure transmission element (22) designed to receive a support pressure exerted by the sacrum (52) of the person (10) and an evaluation unit (30) connected to the pressure transmission elements (21, 22), wherein the evaluation unit (30) is designed to carry out the following steps: a) Receiving and analysing measurement signals from the pressure transmission elements (21, 22); b) Determining a first characteristic pressure distribution (65), in which the first pressure transmission element (21) is first acted upon by at least a part of the seating pressure of the coccyx (51) or the first pressure transmission element (21) is acted upon by at least a part of the support pressure of the pubic bone during a rotation of the pelvis (50) of the person (10) about its horizontal axis; and c) Determining a second characteristic pressure distribution (66), in which the seating pressure of the coccyx (51) exerted on the first pressure transmission element (21) has an abrupt drop and the support pressure of the sacrum (52) exerted on the second pressure transmission element (22) has an abrupt rise.

2. The device (100) according to claim 1, characterised in that the first pressure transmission element (21) and the second pressure transmission element (22) are arranged substantially at an obtuse angle to one another.

3. The device (100) according to any one of the preceding claims, characterised in that the evaluation unit (30) is further designed to periodically evaluate the measurement signals transmitted by the pressure transmission elements (21, 22) to the evaluation unit (30) at a predetermined time interval.

4. The device (100) according to any one of the preceding claims, characterised in that the evaluation unit (30) is a diaphragm unit (37) comprising a diaphragm (31) and connected to the pressure transmission elements (21, 22) via channels, which has a sensor (34) arranged on the diaphragm (31) and a computing unit which is designed to evaluate a sensor signal output by the sensor (34).

5. The device (100) according to any one of the preceding claims, characterised in that the device (100) comprises a third pressure transmission element (23) and a fourth pressure transmission element (24), which are each arranged next to the second pressure transmission element (22) and are designed to absorb the contact pressures exerted by the iliac crests (54) of the person (10).

6. The device (100) according to claim 5, characterised in that the device (100) comprises a fifth pressure transmission element (25) and a sixth pressure transmission element (26), which are each arranged next to the first pressure transmission element (21) and are designed to absorb the seat pressures exerted by the ischial tuberosities (53) of the person.

7. The device (100) according to any one of the preceding claims, characterised in that the device (100) comprises an array with a plurality of pressure transmission elements, which is designed to detect the seat and support pressures of the pelvis (50) of the person (10) in any position of the person (10) on the device (100).

8. The device (100) according to claim 4, characterised in that the sensor (34) is selected from the group consisting of mechanical, electrical, pneumatic or hydraulic sensors.

9. The device (100) according to any one of the preceding claims, comprising a warning means, characterised in that the warning means warns the person (10) when the first characteristic pressure distribution (65) and / or the second characteristic pressure distribution (66) has been determined, wherein the warning means is selected from the group consisting of optical, acoustic or haptic warning means.

10. A computer program product comprising instructions which, when the program is executed by the evaluation unit (30) of the device according to claim 1, cause it to perform the steps of claim 1 with the device according to claim 1.

11. A computer-readable data carrier on which the computer program product according to claim 10 is stored.