WO2007020219A1 - Method for determining and modifying pressure distribution brought about by a human body on a sitting or lying arrangement and said type of sitting and lying arrangement - Google Patents

Abstract

The invention relates to a method for determining and modifying pressure distribution brought about by a human body on a sitting or lying arrangement, wherein a plurality of flexible, gasproof chambers (10a, 10b) are provided. Said chambers (10a, 10b) are grouped into at least one group and can be filled with gas which can be evacuated from the chambers (10a, 10b). At least one pressure value is detected for each chamber (10a, 10b) of the group. A reference value is determined for the group from the pressure values and said reference value is formed from an arithmetic average of the pressure values which are compared to the reference value. If the pressure value does not correspond to the reference value, the difference between the reference value and the pressure value for each chamber (10a, 10b) of the group determines a difference value which determines an amount of gas. The pressure value is subsequently modified to the amount of the difference value in relation to the reference value by filling or evacuating the amount of gas in the chamber (10a, 10b).

Description

 Method for detecting and changing a distribution of pressure on a sitting or lying arrangement caused by a human body and such a sitting or lying arrangement

The invention relates to a method for detecting and changing a pressure distribution caused by a human body on a sitting or lying arrangement. The sitting or lying arrangement is provided with a multiplicity of flexible, gastight chambers, the chambers being divided into at least one group. The chambers can be filled with gas and gas can be evacuated from the chambers. The invention further relates to such a sitting or lying arrangement.

Under a sitting or lying arrangement in the context of the present invention, all types of upholstery are understood, which serve to support the human body.

In the support of the human body as comfortable as possible sitting or lying position of the body is sought to make even a comfortable sitting or lying over a longer period. In order to improve the well-being when sitting or lying down, an examination of the usual sitting / lying position is required in advance, in order to be able to give an assessment of the seating comfort and suggest measures for improving the seating comfort.

From US 2004/0194220 A1 a support member is known, in which a mattress core and a pressure sensor is provided in an envelope, wherein the pressure sensor Sor separately from the mattress core is arranged and measures the pressure exerted by a person on the support member pressure and generates a corresponding signal.

US 5,815,864 A discloses a method for detecting and altering a pressure distribution, caused by a human body, on a lying arrangement that is particularly suitable for patients at risk of pressure ulcers. In the method, the air pressure supplied to a mattress is measured in different load conditions, for example, in a nearly fully inflated or almost completely deflated condition.

Further, US 5,062,169 discloses a hospital bed system having a mattress having a plurality of air chambers, each of which chambers can detect pressure changes caused by the movement of a person lying on the mattress and emit corresponding signals.

Finally, EP 1 092 134 B1 discloses a method for mapping pressure exerted on a vehicle seat in order to make predictions about seating comfort. The known method provides for the measurement of a first field and a second field of pressure point values applied to the seat. The fields each define a print card. The pressure point values are measured with a mat mounted on the seat with a panel of resistive elements, whereby the pressure forces acting on the mat are detected by the person sitting on the mat by measuring the resistance change in the resistive elements. In order to allow an assessment of the seating comfort, it is envisaged that several persons occupy the seat one after another, whereby a print card is obtained for each person. In other words, each print card refers to a specific person. The pressure point values for each cell of the measuring mat are statistically averaged. The data of the print cards are normalized with predetermined thresholds of a reference print card. The threshold values represent minimum pressure values, so that only values that are above this threshold value are taken into account. The normalized data of each print card is then averaged, thereby obtaining data of a single averaged print card. From the comparison of the data can then be based on the difference of the ratios between the data of the averaged pressure map and the data of the reference pressure map a rating of seating comfort.

In this known method, it has proven to be disadvantageous that the determined pressure point values are based on the pressure distribution of different persons and thus do not depend on the individual body shape and the individual body weight of the individual user. Thus, it can only come to an average adjustment of seating comfort, without specifically addressing the needs of the individual user.

In order to enable a comfortable sitting, it is also known to integrate a massage device in a seat. EP 1 447 070 A1 discloses such a seat with a massage device and a method for performing a massage. The massage device is disposed in the seat below a seat cover and comprises a plurality of flexible containers made of plastic film, which are connected via lines to a pump and to a control unit. The containers comprise a multiplicity of chambers which can each be controlled separately and filled with gas or evacuated. Below the container, a pressure sensor is arranged, which detects whether the seat is occupied. Underneath is a padding made of foam. When performing the massage, the cam- in a predetermined order individually or in pairs in a repetitive sequence filled with gas or evacuated, so as to achieve a massage effect. With regard to the filling states of the chambers, a distinction is made between a filled state and a deflated state. When filled, the pressure in the container is greater than the pressure exerted on the seat. A control unit can determine the pressure exerted by the user on the seat and depending on the gas pressure in the containers change. To adapt the seat to the body shape of the user and for local support in the area of the loins, certain containers can be provided with a constant pressure.

In the described construction of the seat, it has proven to be problematic that the detection of the pressure exerted on the seat takes place only over a large area. The pressure sensor provided for this purpose is arranged below the container of the massage device and should only detect whether the seat is occupied. In the event that the seat is occupied, then the massage process can be activated. As a result of this adjacent arrangement of massage device and pressure sensor, the pressure caused by an unavoidable residual gas volume in the containers influences the pressure sensor and thus influences the measurement results. Furthermore, the actual upholstery of the seat is provided below the massage device. The supporting effect of the foam padding is always the same. Although certain gas containers can also be kept under constant pressure, this is done independently of the pressure exerted on the seat.

The invention has for its object to provide a method for detecting and changing a caused by a human body pressure distribution on a sitting or lying arrangement with which an improved seat or lying comfort can be achieved. In addition, such a seating or lying arrangement should be specified. To achieve this object is in a method for detecting and changing a caused by a human body pressure distribution to a sitting or lying device, which is provided with a plurality of flexible, gas-tight chambers, wherein the chambers are divided into at least one group and wherein the chambers are fillable with gas and gas is evacuable from the chambers, according to the invention, in accordance with claim 1, that the method comprises the steps of: a) detecting at least one pressure value for each chamber of the group; b) determining a reference value from the pressure values for the group, the reference value being formed from an arithmetic mean of the pressure values; c) comparison of the pressure values with the reference value; d) determination of a difference value from the difference between the

Reference value and the pressure value for each chamber of the group, if the pressure value does not correspond to the reference value; e) determination of a gas quantity based on the difference value; f) changing the pressure value by the amount of the difference value to the reference value by filling or evacuating the

Amount of gas in the chamber.

The method according to the invention is based on the knowledge that the uniform pressure distribution caused by the change of the pressure values to the reference value makes possible optimal sitting or lying comfort. In this form of support thus occur no point loads on the body.

With the invention, a sitting or lying comfort that is individually tailored to the individual user is created. This is achieved independently of comparison measurements with other users and thus requires no Complex collection of a large amount of comparative data to arrive at a meaningful result.

The method according to the invention makes it possible to set a uniform pressure over the sitting or lying surface, whereby the necessary change in the pressure values is minimized. This is due, in particular, to the fact that the sum of the difference values is lower than in the case in which all chambers are brought to a pressure value which is, for example, greater than the maximum value of the detected pressure values or less than the minimum value of the detected pressure values. The difference values determined for setting the optimum pressure distribution are thus minimized, whereby the measures required to achieve this state, such as, for example, the provision of a quantity of gas to be filled, are less complicated than in conventional methods. This leads to a cost and time savings.

For detecting the pressure values, a pressure measuring device with a plurality of pressure sensors is used. The pressure sensors can be designed as pressure-sensitive resistance elements, wherein the pressure sensors detect the resulting due to the pressure distribution resistance change in the resistance elements and each convert into a pressure value. The pressure measuring device is preferably designed in the form of a flexible, flexible, preferably textile-like mat with resistance elements arranged in a grid pattern at regular intervals.

The method according to the invention is preferably used for determining and changing the pressure distribution in a vehicle seat, in particular in a motor vehicle seat. Especially for longer trips with a motor vehicle, there is a great need for optimum seating comfort. Furthermore, it should be noted in this connection that the explanations which are generally referred to below in a seated position are readily transferable to a lying position. Advantageous developments of the method according to the invention are described in claims 2 to 8.

In an advantageous development of the method it is provided that the chambers are divided into several groups and the reference value for each group is formed from the arithmetic mean of the pressure values of the chambers assigned to these groups. As a result, a separate reference value is determined for all groups and thus a locally adjusted pressure distribution is set for all chambers.

In a further development of the method according to the invention, it is proposed that the pressure value corresponds to the pressure exerted on the respective chamber. As a result, it is possible, for example, to use a mat integrated in the seat or a mat placed on the seat for detecting the pressures exerted on the chambers. Such a mat can also be integrated in a seat cover.

In a further advantageous development of the method, it is provided that the pressure value corresponds to the pressure prevailing in the respective chamber. Thus, the pressure sensors can also be provided directly in the chambers in order to measure the gas pressure present there. In order to achieve a redundant design, both the pressure exerted on the chamber and the pressure prevailing in the chamber can be determined.

It is also advantageous if the pressure value for a chamber is derived from a plurality of measured pressure values. This increases the accuracy of the results and their statement quality and leads to an improved pressure adjustment. In this case, the pressure value for a chamber is preferably formed from an arithmetic mean of the pressure values. The pressure values are preferably detected by a pressure measuring device which has a plurality of pressure sensors in the manner of a grid. This proves to be particularly advantageous in an embodiment of the pressure sensors for detecting the pressure exerted on the chambers. Thus, for example, a textile-like mat placed on the seat with a grid of resistance elements can be used as a pressure measuring device.

In order to be able to make an adjustment of the gas pressures in the chambers before the seat or lying arrangement is used, it is expedient if the determined pressure values, reference values and difference values are stored in a memory unit. As a result, already determined data values can be retrieved for a specific person.

Moreover, to achieve the above object in accordance with claim 9, a seat or lying arrangement, in particular a motor vehicle seat, proposed, comprising the following components: a) a plurality of flexible, gas-tight chambers, which are divided into at least one group, wherein the Chambers are filled with gas and from the chambers gas is evacuated; b) a plurality of cushioning elements, wherein the cushioning elements are arranged in the chambers; c) a pressure measuring device with a plurality of pressure sensors, wherein for each chamber at least one pressure sensor for detecting at least one pressure value for each chamber of the group is provided; d) a control unit for determining a reference value for the group, a difference value for each chamber of the group and a gas quantity according to the method of one of claims 1 to 8; e) a gas pump for changing the pressure value by the amount of the difference value to the reference value by filling or

Evacuate the amount of gas in the chamber. Such a formed sitting or lying arrangement makes use of the advantages of the method according to the invention. In addition, the arrangement of the padding elements in the chambers ensures a reliable informational value of the measurement and calculation results since, in a conventionally separate arrangement of padding elements and chambers, the pressure values measured for the individual chambers are influenced by the presence of the foam material Upholstery elements can not be excluded.

Advantageous embodiments of the seating or lying arrangement according to the invention are described in claims 10 to 17.

According to the above statements on the method according to the invention, it proves to be advantageous if the pressure sensor detects the pressure exerted on the chamber. Alternatively or additionally, the pressure sensor can detect the pressure prevailing in the chamber. To increase the accuracy of the results, each chamber may be associated with a plurality of pressure sensors. Advantageously, the pressure sensor is a piezoelectric force transducer.

A preferred embodiment consists in that the padding elements consist of a foam, in particular of an open-cell flexible foam. The flexible foam is expediently a molded polyurethane foam. Thus, the upholstery elements can be given an ergonomic shape which is largely adapted to the body shape.

In a preferred embodiment, the chambers are each formed from a film, which preferably consists of polyurethane, polyamide or polyethylene. The films can be easily connected to the molded foam, for example by back-foaming. Preferably, the chambers are each materially connected to the cushion element. This allows licht a simple and inexpensive production by foaming a film attached in a mold.

The invention will be explained below with reference to the drawings. Here are shown schematically:

Fig. 1 is a perspective view of a seat assembly according to the invention and

2 shows a cross section along the line M-II in Fig. 1st

1 and 2 show schematically an embodiment of a seat / recliner arrangement according to the invention in the form of a motor vehicle seat with a schematically illustrated division into a plurality of chambers 10a, 10b. In this case, a seat 12 has nine chambers 10a, which form a first group, and a backrest 13 has twelve chambers 10b, which form a second group. In each chamber 10a is a cushion member 11a and in each chamber 10b, a cushion member 11b is arranged. The cushion elements 11a, 11b are each formed from a molded polyurethane foam. The chambers 10a, 10b are each formed from a flexible polyurethane film and each include one of the cushion elements 11a, 11b gas-tight.

The usual in such a motor vehicle seat components, such as a seat for the Auflagerung the upholstery elements, a heater and ventilation, are not shown for the sake of simplicity, but readily integrable.

Furthermore, each chamber 10a, 10b is connected by a respective line 41 to a gas pump 40, so that each chamber 10a, 10b can be filled separately with a predetermined amount of gas or a certain amount of gas from the chambers 10a, 10b can be evacuated. This can be seen in Fig. 1 by the solid lines, this being only by way of example with reference to three lines 41 is indicated. The lines 41 are, as already explained, provided between each of the chambers 10 a, 10 b and the gas pump 40.

As can be seen primarily from FIG. 2, a pressure measuring device 20 with 21 pressure sensors 21a and 21b is arranged above the chambers 10a, 10b. In this case, the pressure sensors 21a are provided in the region of the seat surface 12 and the pressure sensors 21b in the region of the backrest 13. The pressure sensors 21a, 21b are positioned so that they are arranged approximately centrally with respect to the respective chamber 10a, 10b. Furthermore, the pressure sensors 21a, 21b are designed so that they can measure the pressure exerted on the individual chambers 10a, 10b by a user of the motor vehicle seat. The pressure measuring device 20 represents a flexible mat, which may be integrated in a seat cover of the motor vehicle seat, which rests on the chambers 10a, 10b. Alternatively, this mat can also be arranged below the cover. Furthermore, an intermediate layer can optionally be provided between the chambers 10a, 10b and the pressure-measuring device 20 so as to avoid possible damage to the film of the chambers 10a, 10b.

In order to enable an evaluation of the pressure values measured with the pressure sensors 21a, 21b, the pressure sensors 21a, 21b are each connected to a control unit 30. This can be seen in FIG. 1 with reference to the dashed lines, which is indicated only by way of example with reference to three dashed lines. The connections are, as already explained, provided between each pressure sensor 21a, 21b and the control unit 30. The control unit 30 may be integrated in the motor vehicle seat. For controlling and activating or deactivating the gas pump 40, the control unit 30 is connected to the gas pump 40.

In the following, the method according to the invention will be explained with reference to an example, for which the motor vehicle seat according to FIGS. 1 and 2 is used. After occupying the motor vehicle seat by a person, each of the nine pressure sensors 21a in the region of the seat 12, that is to say in the region of the first group, respectively measures a pressure value of the pressure exerted on the chambers 10a. Then a first reference value for this first group is determined. which corresponds to the arithmetic mean of the measured pressure values. Subsequently, after an individual comparison of the pressure values with the first reference value and for the case that the corresponding pressure value does not correspond to the first reference value, a difference value from the difference between the first reference value and the respective pressure value is determined in each case for the chambers 10a in question. Based on the difference values thus determined, a gas quantity is now determined for each of the chambers 10a. These gas quantities are then introduced into the chambers 10a by means of the gas pump 40 or have to be evacuated from the chambers 10a. Thereby, the original pressure value is adjusted to the first reference value, whereby all the chambers 10a have the same pressure value in the height of the first reference value. This results in a uniform pressure distribution over the seat 12, which ensures ergonomic support.

In a corresponding manner, for the backrest 13, that is, in the area of the second group, proceeded. The associated twelve pressure sensors 21b each detect a pressure value for the twelve chambers 10b. From the measured pressure values, a second reference value is formed, which corresponds to the arithmetic mean of the measured pressure values and is assigned to the second group. In accordance with the procedure for the seat 12, the gas quantities to be filled or the quantities of gas to be evacuated for the individual chambers 10b are obtained as a result. These amounts of gas are then filled or evacuated by means of the gas pump 40. Thereby, the original pressure value is adjusted to the second reference value, whereby all the chambers 10b of the second group have the same pressure value in the second reference value Height of the second reference value. This results in a uniform pressure distribution over the seat 13th

If it is determined that the pressure value of any chamber 10a, 10b corresponds to the associated reference value, no change in this pressure value is necessary. The determination and change in the pressure distribution takes place for the seat 12 and backrest 13 in parallel. Alternatively, the chambers 10a, 10b could only form one group and a reference value for all chambers 10a, 10b could be determined.

LIST OF REFERENCE NUMBERS

a chamber in the region of the seat surface 12 b chamber in the region of the backrest 13 a cushion element in the region of the seat surface 12 b cushion element in the region of the backrest 13 seat backrest

Pressure measuring device a Pressure sensor in the area of the seat surface 12 b Pressure sensor in the area of the backrest 13

control unit

Gas pump pipe

Claims

claims A method of detecting and altering a human body's pressure distribution to a sitting or lying arrangement provided with a plurality of flexible, gas tight chambers (10a, 10b), said chambers (10a, 10b) being in at least one group and wherein the chambers (10a, 10b) are fillable with gas and gas is evacuable from the chambers (10a, 10b), the method comprising the steps of: a) detecting at least one pressure value for each chamber (10a, 10b) of the group; b) Determination of a reference value from the pressure values for the Group, wherein the reference value is formed from an arithmetic mean of the pressure values; c) comparison of the pressure values with the reference value; d) determining a difference value from the difference between the reference value and the pressure value for each chamber (10a, 10b) of the group if the pressure value does not correspond to the reference value; e) determination of a gas quantity based on the difference value; f) changing the pressure value by the amount of the difference value to the reference value by filling or evacuating the gas quantity into the chamber (10a, 10b). 2. The method according to claim 1, characterized in that the chambers (10a, 10b) are divided into several groups and the reference value for each group from the arithmetic mean of the pressure values of these groups associated chambers (10a, 10b) is formed. 3. The method according to claim 1 or 2, characterized in that the pressure value corresponds to the pressure exerted on the respective chamber (10a, 10b). 4. The method according to claim 1 or 2, characterized in that the pressure value corresponds to the pressure prevailing in the respective chamber (10a, 10b). 5. The method according to any one of claims 1 to 4, characterized marked, that the pressure value for a chamber (10a, 10b) is derived from a plurality of measured pressure values. 6. The method according to claim 5, characterized in that the pressure value for a chamber (10a, 10b) is formed from an arithmetic mean of the pressure values. 7. The method according to any one of claims 1 to 6, characterized in that the detection of the pressure values with a pressure measuring device (20), the grid-like a plurality of pressure sensors (21 a, 21 b). 8. The method according to any one of claims 1 to 7, characterized in that the pressure values, the reference values and the difference values are stored in a memory unit. 9. sitting or lying arrangement, in particular a motor vehicle seat, comprising: a) a plurality of flexible, gas-tight chambers (10a, 10b), which are divided into at least one group, wherein the chambers (10a, 10b) are filled with gas and from the chambers (10a, 10b) gas is evacuable; b) a plurality of cushioning members (11a, 11b), wherein the cushioning members (11a, 11b) are disposed in the chambers (10a, 10b); c) a pressure measuring device (20) having a plurality of pressure sensors (21a, 21b), wherein for each chamber (10a, 10b) at least one pressure sensor (21a, 21b) for detecting at least one pressure value for each chamber (10a, 10b) of the group is provided; d) a control unit (30) for determining a reference value for the group, a difference value for each chamber (10a, 10b) of the group and a gas quantity according to the method of one of claims 1 to 8; e) a gas pump (40) for changing the pressure value by the amount of the difference value to the reference value by filling or evacuating the amount of gas into the chamber (10a, 10b). 10. sitting or lying arrangement according to claim 9, characterized in that the pressure sensor (21 a, 21 b) detects the pressure exerted on the chamber (10 a, 10 b). 11. sitting or lying arrangement according to claim 9, characterized in that the pressure sensor (21 a, 21 b) detects the pressure prevailing in the chamber (10 a, 10 b). 12. sitting or lying arrangement according to one of claims 9 to 11, characterized in that each chamber (10 a, 10 b) a plurality of pressure sensors (21 a, 21 b) are assigned. 13. sitting or lying arrangement according to one of claims 9 to 12, characterized in that the pressure sensor (21 a, 21 b) is a piezoelectric force transducer. 14. sitting or lying arrangement according to one of claims 9 to 13, characterized in that the cushion elements (11 a, 11 b) made of a foam, in particular of an open-cell soft foam, consist. 15. sitting or lying arrangement according to claim 14, characterized in that the flexible foam consists of polyurethane. 16. sitting or lying arrangement according to one of claims 9 to 15, characterized in that the chambers (10 a, 10 b) are each formed from a film which preferably consists of polyurethane, polyamide or polyethylene. 17. sitting or lying arrangement according to one of claims 9 to 16, characterized in that the chambers (10 a, 10 b) in each case materially connected to the cushion element (11 a, 11 b) are connected.