Adaptive cushion method and apparatus for minimizing force concentrations on a human body

[0001] The present invention relates to methods, articles and a device intended to comfortably support a human body in a sitting or lying position. In particular, the invention relates to a method and a device for minimizing the concentration of forces affecting supported body parts by means of an adaptive cushion equipped with a matrix of flexible air-filled bubbles, dynamically compressed, according to the readings of forces acting on the sensors covering the flexible bubbles.

B. Description of the Related Art [0002] When the body is supported by any object, such as a chair or bed, normal and shear forces generated in response to the weight of the unit are transferred from the supporting surface through the skin, adipose tissue, muscles, etc. to the skeleton. Forces that exert pressure on body parts through load-bearing surfaces that are even and opposite to the body's gravity can in some cases lead to tissue damage. Forces exerting pressure on body parts can compress internal blood vessels and prevent nutrients from entering tissues, and the combination of intensity and duration of these forces determines whether tissue damage or disease occurs. It is understood that only strong pressure usually does not lead to tissue damage. For example, deep-sea divers who are exposed to large, but evenly distributed naturally interacting forces do not suffer from tissue damage. However, when a sufficiently strong external pressure gradient affects a particular part of the body on the body, for example, as a result of the low pressure surface adhering to the high pressure area, internal body fluids may migrate to the lower pressure area. Tangential or shear forces exerting external pressure on body parts can also break down internal capillaries and blood vessels by deforming them longitudinally. Knowledge of both the surface force gradient (pressure gradient) and the external lateral force exerting pressure on the tissue is therefore extremely important, because the combination of these factors leads to tissue damage and, as a consequence, its death. Thus, even relatively small external lateral and normal forces, which can exert pressure independently of each other, in combination can exert transverse pressure on internal tissue. The areas of the human body most at risk of tissue damage, for example bedsores, include the heel, sciatic tumors, greater trochanter, occiput and sacrum.

[0003] Various pressure / force sensors, transverse force sensors and sets of sensors are used to measure the normal and transverse forces affecting the tissues of the human body. For example, another patent of the present inventor, US Patent No. 5.7 (51), 973, dated November 5, 1996, Multi-Directional Piezoresistive Shear And Normal Force Sensors For Hospital Mattresses And SeatCushions [omnidirectional piezoresistive sensors of normal and transverse forces affecting hospital mattresses and seat cushions discuss thin, flat sensors for measuring forces on the body of a lying or sitting patient. One of the uses of the invention discussed in the '973 patent uses a sensor consisting of a two-dimensional set of insulated sensor pads, each consisting of a thin, flat layer made of a non-conductive elastomeric polymer matrix filled with electrically conductive particles. The matrix of upper and lower conductive elements in electrical contact with the upper and lower sides of each sensor pad allows separate measurements of the electrical resistance of each pad. Pressure exerted The pressure exerted on each pad, e.g. in response to the normal force exerted on the sensor matrix by the human body, reduces the thickness of the sensor pad and thus its electrical resistance by the piezoresistive effect of mass or volume.

[0004] The present inventor in the US patent specification. Stalemate. No. 6,216,5 (45), April 17, 2001, Piezoresistive Foot Pressure Measurement, a new way and device for measuring pressure on human feet or horse hooves. The new apparatus presented in the "5 (45) patent includes a rectangular set of piezoresistive force sensor elements enclosed in a thin, flexible polymer packaging. Each sensor element contains a polymer mesh impregnated with conductive particles suspended in an elastomeric matrix, such as silicone rubber. The piezoresistive mesh layer is sandwiched between a set of strip shaped fittings of row and column conductors, preferably if it is made of nylon mesh impregnated with printed metallic paths. Each region of the piezoresistive material placed between the row conductor and the column conductor contains an individually addressed normal force or pressure sensor in a rectangular set of sensors whose resistance varies inversely in a manner predetermined as a function of pressure exerted on the sensors, and thus allows the distribution of force pressure exerted by the object in contact with the assembly to be mapped.

[0005] In US Patent No. 6543299, of April 8, 2003, Pressure Measurement Sensor With Piezoresistive Thread Lattice, the present inventor presents a set of transducer sensors for measuring forces or pressures exerted on a surface, the kit includes two-dimensional fabric-like the individual force grille or pressure sensor transducer elements containing intersecting regions of pairs of elongated elastic threads, each consisting of a central conductive wire core covered with a layer of piezoresistive material, which has electrical resistivity that changes inversely in proportion to the pressure exerted on the material.

[0006] In US Patent No. 7,201,063, April 10, 2007, Normal Force Gradient / Shear Force Sensors And Method Of Measuring Internal Biological Tissue Stress [The present inventor's method of measuring internal biological force sensors] presented the normal force gradient / transverse force sensor and how to measure internal forces in the tissues of a person supported by a chair or bed. The device includes a flat matrix set of peripheral normal force sensors, radially spaced from the central transverse force sensors, each containing an electrically conductive disk located in a circular hole surrounded by circumferentially spaced electrodes. The disk and electrodes are placed between the upper and lower protective sheets made of a flexible material such as polyurethane, one sheet of the protective sheet adheres to the disk, and the other sheet to the sheet supporting the electrodes. The movement between the protective sheets in response to lateral forces exerted on the set causes the disk to be pressed more or less against the electrodes, thereby changing the electrical conductance between the disk and the electrodes in proportion to the size and direction of the transverse force. Each normal force sensor includes an electrically conductive layer sandwiched between row and column wires. Measurements of the conductivity value of the sensor pairs that change in proportion to the normal forces exerted on the sensor are used to calculate the gradient vector of normal forces exerted by a body part on a set of sensors that connect to the transverse force vectors in an algorithm to calculate the internal transverse force response, e.g. on the body near bone haemorrhage.

[0007] The first group of patents of the present invention defined above provided transverse and normal force sensors and sensor sets that are useful in producing maps of normal and transverse forces exerted on separate surface areas, such as parts of the human body, by objects such as the bearing surface of a chair or beds. The last of the patents of the present inventor discussed above has provided effective means for measuring lateral force and stress exerted on human tissues that are at some depth below the surface of the skin.

[0008] In US Patent No. 6,721,9 (80), Force Optimization Surface Apparatus And

Method [Surface apparatus and method for optimizing forces], the present inventor and co-inventors presented a device, including a mattress, which included a plurality of transversely spaced cylindrical sausage-shaped air chambers equipped with individual pressure sensors. The device consisted of a mechanism for single-pumping air into each flexible air-filled bubble, monitoring the pressure in each flexible bubble while a person was lying on a mattress monitoring the pressure exerted on a given flexible bubble, adjusting the pressure of a single flexible bubble to minimize the pressure exerted by the flexible bubble on the human body and repeating the above steps in turn for each air-filled flexible bubble.

[0009] The method described in US Patent No. 6,721,9 (80) for measuring the force exerted by a human body on a single air-filled flexible bladder while regulating the inflation pressure in a flexible bladder may be suitable for single systems of air-filled flexible bladders and under conditions in which the body supported patient freely adapts to the supporting surface. However, for more common cases, patients sitting astride, in which the body is supported by adjacent flexible air-filled bubbles, the pressure on the bubble is checked, whose air pressure is adjusted, so that the pressure exerted can be minimal. However, pressure that can reduce the pressure on a given air-filled elastic bubble will usually not be optimal pressure relative to the minimum total concentration of force concentration on the human body. This is because while the force acting on a given air-filled elastic bubble can be minimized, the forces exerted on the air-filled elastic bubble adjacent to the air-filled elastic bubble whose pressure varies can be much greater because the weight of the load is moved to the neighboring flexible tanks. A device for supporting the body with automatic pressure control is shown in WO2005 / 104904 A1.

[0010] A similar limitation on the methods of the technique and the device arises when a part of a patient's body is supported in a self-supporting manner by one or more adjacent flexible air-filled bubbles and the pressure in a given flexible air-filled bubble changes. Also in this case, load forces are transferred to adjacent flexible air-filled bubbles. Therefore, it would be desirable to provide a method and device that would take into account all forces exerted on all air-filled flexible bubbles during pressure changes in any single flexible bubble. The idea behind the present invention of the present invention was to provide a method and device for minimizing the concentration of volumetric force on a part of a human body supported by a chair seat or bed, and measuring forces exerting pressure on body parts.

OBJECT OF THE INVENTION [0011] The object of the present invention is to provide a method and device for an adaptive cushion to minimize the effect of pressure exerted by a bed, chair or other objects of this type on a body part of a person lying or sitting on an object.

[0012] Another object of the invention is to provide a method and device for an adaptive pillow, including a pillow constituting a mattress cover for a bed or chair, a cushion equipped with a matrix of individually inflatable flexible air-filled bubbles and a set of surface force transducers equipped with a single sensor vertically fitted to all flexible air-filled bubbles and an electronic control system for receiving force sensor signals and dynamic differentiation of the introduced pressure used in individual air-filled flexible bubbles, to introduce or deflate individual chambers to obtain a pressure calculated by the control system algorithm to minimize the concentration of forces on body parts supported by the cushion.

[0013] Another object of the invention is to provide tensile surface force transducers that adapt to the protrusion of the human body.

[0014] Another object of the invention is to provide tensile surface force sensors that have an asymmetrical diode current rather than voltage transfer function.

[0015] Another object of the invention is to provide a matrix set of extensible surface force transducers that have non-bilateral current versus voltage transfer functions, thus minimizing crosstalk ambiguities occurring during the XY addressing of individual sensors to map the forces exerted on the set.

[0016] Various other objects and advantages of the present invention and its latest capabilities will become apparent to those skilled in the art upon reviewing the attached specification, drawings and claims.

[0017] It should be understood that although the invention presented herein is fully capable of achieving the objectives and providing the benefits described, the features of the invention described herein are merely an example of its preferred uses. Therefore, the scope of my exclusive rights and privileges related to the invention is not limited to the details of the applications described here. Equivalents, adaptations and modifications of the invention that can be deduced from the description herein are within the scope of the invention as defined in the appended claims. SUMMARY OF THE INVENTION [0018] In short, the present invention includes a device as claimed

1.

[0019] In a typical embodiment of an adaptive cushion suitable for use on a bed, flexible air-filled bubbles can be placed in a 6x2, XY rectangular mesh, thereby dividing the cushion into columns located on the left and on the right, each with 6 zones longitudinally spaced beds from head to foot.

[0020] The adaptive cushion device of the present invention also includes a flexible, stretchy, flat, newly constructed set of force transducers, which is preferably located on the upper surface of the cushion and has at least one sensor vertically positioned relative to the individual air-filled elastic bubbles of the cushion.

[0021] The set of sensors according to the present invention comprises wires located in rows and columns of stretchable fabric that fit between the inner conductive surfaces and the stretchable sheet of fabric coated with piezoresistive material. The flat sensor set constructed in this way is elastically deformable in response to the forces exerted on the set by the weight of the human body supported on the upper surface of the set of sensors covering elastic bubbles filled with air. Preferably the set of sensors is placed on the upper surface of flexible air-filled bubbles and held in this position by means of a body-fitting cover. The material dies for wires in rows and columns and the middle piezoresistive layer are made of a material that is elastically deformable in any direction in the material plane. In an example of a preferred application, the material matrices or wire sheets in the rows and columns are coated with a copper primer and a nickel coating. The middle piezoresistive sheet consists of a matrix made of synthetic fabric covered with a piezoresistive coating. The sensor set also has an upper protective sheet made of a material such as Lycra and is characterized by bi-directional stretch, i.e. it is elastically stretchable in perpendicular directions.

[0022] The adaptive cushion device of the present invention includes an electropneumatic controller that effectively controls alternating pressure by maintaining high pressure in individual air-filled elastic bubbles by venting them in response to forces exerted by the human body on individual sensors connected to air-filled elastic bubbles. The electropneumatic controller is equipped with an electronic control system for separately transferring voltage or current to each force sensor and measuring the resultant current or voltage in order to determine the electrical resistance of the sensor, which is inversely proportional to the force or pressure exerted on the sensor, e.g. by a person sitting or lying on a pillow covered with a set of sensors.

[0023] The electronic control system also includes a computer that receives as input power electrical signals from individual representative sensors regarding their resistance, and thus the force or pressure exerted on the upper surface of each sensor.

[0024] The device for minimizing the volumetric force of the present invention is also equipped with a pneumatic system with a source of compressed air, such as a compressor, for introducing compressed air through various and individually controllable inlet manifolds into individual flexible air-filled bubbles. The device also includes an air pressure transducer to monitor the pressure in the selected flexible bubble and output a representative electrical signal of the measured pressure to the computer.

[0025] The inlet valves of the individual flexible air-filled bubbles are electrically controlled and in the first, open position, air from the collector output connection is directed to the selected flexible air-filled bubble to be inflated to the desired level, and in the second position they are closed, which allows maintaining the desired pressure in the bubbles. The pneumatic system is also equipped with a breather valve connected to the inlet of the collector. With the vent valve and the selected value of the elastic air-filled bubble in the second, open position, compressed air from the selected elastic air-filled bubble is discharged outside through the exhalation port of the vent valve to reduce the pressure in individual flexible air-filled bubbles to a lower, controllable value . Each valve is electrically connected to the computer's control output port and is effectively controlled by signals at the control output port.

[0027] The present invention also includes a method of electronic control of the device for minimizing the volumetric force. The method includes an algorithm used in the computer control system. This algorithm receives as input power measurements from individual flexible air-filled bubbles and sends control signals that individually adjust air pressure in individual flexible air-filled bubbles to values ​​that are effective in reducing the concentration of forces affecting the concentration of force on body parts supported by the pillow.

[0028] According to the algorithm, before a person lies down or sits on a cushion, individual elastic bubbles filled with air are inflated to a predetermined upper pressure, which can be the same or different in individual bubbles. Then the person is placed on the cushion, and the forces exerted by his body on each sensor are initially monitored by computer-controlled measurement of the electrical resistance of each force sensor. First, under the control of the computer, a flexible bubble filled with air from the "first zone" is bled to the predetermined lower pressure. Although the first zone may correspond to any single air-filled elastic bubble, for example, the value of the 6-row bubble and 2 columns of air-filled elastic bubble for use on the bed, the best approach being to select as the first zone for which the value the impact of volumetric force measured in the initial monitoring process was the highest.

[0029] During the stage of deflating the first flexible bubble filled with air from the first zone, which takes place in a slowly changing, increasing manner, the forces exerted on each of the flexible bubbles, including the bubble from the first zone, are measured, and the sum and optionally the average of these forces are calculated by the computer. At the end of the deflation step, it is noted that the pressure corresponds to the smallest sum and average of all force sensor readings. The bubble from zone one is inflated again to a pressure corresponding to the smallest sum and average of the force sensor readings to complete the cycle for zone one.

[0030] The pressure increase cycle described above for the first zone is repeated for the other zones of the elastic air-filled cushions. Preferably, the sequence of cycles of increasing pressure for deflating and re-inflating corresponds consecutively to lower force concentrations. In other words, the first zone is chosen as the zone in which the highest volumetric force of the surface was measured, the second zone would correspond to the zone having the second highest volumetric force measurement, etc.

[0031] After the pressure boosting cycle for each of the adaptive cushion zones, these steps are repeated for all zones, but using a reduced pressure range, i.e. lower than a set upper pressure value and higher than a set lower pressure value. The sequence is then repeated until subsequent smaller adjustments to the force value reading fall below a predetermined threshold, after which the cyclic system operation returns to the passive state.

[0032] In a passive state, the computer monitors each force sensor output. The restoration of the control system to active cyclical operation is initiated by a significant change in any force measurement above a predetermined threshold, for example in response to patient movements.

BRIEF DESCRIPTION OF THE DRAWINGS [0033]

Figure 1 is a partially schematic perspective view of a body support pillow device with adaptive minimization of the concentration of volumetric force in accordance with the present invention.

Figure 2A shows a fragmentary perspective view from above of the device from Figure 1, showing the cover of the device sensors set removed from the mattress pad cushion, located on the device seat, thanks to which individual flexible bubbles filled with mattress air are visible.

Figure 2B shows a fragmentary view of the mattress topper in Figure 2A so that a single air-filled bubble is visible.

Figure 3 is a schematic side view of the device in Figures 1 and 2, showing selected flexible air-filled bubbles from which the air is released to reduce the forces exerted on parts of the human body supported by the mattress pad.

Figure 4 shows a vertical cross-section of the mattress in Figure 2 taken in the direction of line 4-4.

Figure 5 shows a fragmentary composite perspective view of the mattress of Figure 1, showing elements of the force sensor system.

Figure 6 shows a schematic view of the preferred relationship between the dimensions of adjacent elements of air-filled bubbles and the width of the insulation strip between the sensor wires in the bubbles.

Figure 7 shows a diagram of the electrical resistance against the normal force for the sensors in Figure 5.

Figure 8 is a partially schematic view of the favorable modification of the sensor kit components in Figure 1, equipped with a diode connector.

Figure 9 shows the current to voltage (IV) diagram for the sensor components in Figure 8.

Figure 10A is a schematic diagram showing the matrix of sixth row sensors and the second column in Figure 5.

Figure 10B presents a view similar to the one shown in Figure 10A, but shows modified sensors with a diode connector.

Figure 11 shows a block diagram of the elements of the electropneumatic device controller from Figure 1.

Figure 12 shows a simplified perspective view of the electropneumatic controller in Figure 11.

Figure 13 shows a diagram of the device operation in Figure 1.

DESCRIPTION OF THE PREFERRED APPLICATION OF THE INVENTION [0034] Figures 1-13 illustrate various aspects of a method and apparatus for minimizing the concentration of volumetric force on the human body by using an adaptive cushion in accordance with the present invention. Examples of use of the invention shown in Figures 1 and 3 include an adaptive pillow whose size and shape are suitable for use on a standard single bed or hospital bed. However, as will be apparent from the description of the application example, the size and shape of the adaptive cushion may vary depending on the application, for example in a chair or wheelchair.

[0035] Referring first to Figures 1 and 2A, the adaptive cushion device (20) for the minimum concentration of volumetric force on the body of a person lying on the bed may include a longitudinal rectangular cushion constituting the overlay (21). The pillow (21) has the right dimensions and shape to fit a standard size hospital bed. Thus, the cushion embodiment (21) has a laterally elongated, rectangular shape about 6 feet long, about 3 feet wide, and about 4 inches thick.

As shown in Figures 1 and 2A, the mattress pad (21) is constructed as a rectangular, two-column, six-row set of 12 single inflatable flexible air-filled bubbles (22). Each flexible air-filled bubble (22) has a laterally elongated, rectangular shape, about 18 inches long, about 17 inches deep, and about 4 inches thick. As shown in Figures 1 and 2, the flexible bubbles (22) are positioned in the left and right columns, each comprising 6 longitudinally separated, laterally spaced and laterally elongated flexible bubbles. As shown in Figures 2B and 4, each flexible air-filled bubble is equipped with a flat base panel (23), end panels on the left and right (24), (25), panels for the head and toes or front and the rear panels (26), (27) as well as the top panel (28). The flexible bubbles (22) should be made of a thin sheet of flexible material, preferably of elastomeric material, such as neoprene rubber or polyurethane, about 0.014 inch thick. The six panels of each flexible air-filled bubble (22) are tightly connected to each other by edges, forming a hermetically sealed body enclosing the empty inner space (22A). Optionally, each air-filled elastic bubble (22) can be manufactured from pre-formed cylindrical elements in which each end wall is sealed to the transverse opposing ends of the pre-formed cylindrical elements. In each solution, the adjacent panels of a single flexible air-filled bubble are tightly connected by a suitable method, such as ultrasonic welding, dielectric welding or gluing.

[0037] The amount, size, shape, relative position and arrangement of flexible air-filled bubbles (22) on the mattress topper (21) are not considered critical. However, it is believed to be advantageous if the mattress cover (21) is arranged symmetrically so that the left and right side columns have at least five, preferably six longitudinal zones corresponding to the main curvature of the longitudinally located middle section of a typical human body. Thus, as shown in Figures 1, 2A and 3, the mattress cover (21) includes in the left column six flexible air-filled bubbles (22L1) - (22L6) and six bubbles in the right column (21 R1) - (21R6).

[0038] As shown in Figures 1 and 4, the flexible bubbles (22) are arranged close to each other at the front, back and sides, with minimum longitudinal and transverse distances (29), (30), and in the most advantageous application they are so negligible small, adherent elastic bubbles physically touch each other.

[0039] As shown in Figures 1, 2A and 2B, each flexible air-filled bubble (22) is provided with a cylindrical air inlet (31) which projects through the side wall, e.g. a wall on the left or right (24) or (25), and connects to the hollow internal space (22A) in a flexible bubble. The supply of air or the discharge from the interior of the empty space (22A) through the opening (31) in the air-filled elastic bubble (22) allows the introduction or release of air to obtain the selected pressure.

[0040] Although each flexible air-filled bubble (22) of the cushion (21) shown in Figures 1 and 2 is in the shape of a rectangular block or parallelepiped, the flexible air-filled bubble may optionally have other shapes, such as convex hemispheres protruding upward from the base of the cushion . In addition, the arrangement of flexible air-filled bubbles flexible air-filled bubbles (22) of the cushion (21) may have a uniform structure with a common base panel (23) and may be in the form of a single rectangular block, a hemispherical or hollow inflatable body with other shapes that protrude top with a common unified base panel.

[0041] If the individual flexible air-filled bubbles (22) are separate bodies or top-inflated shell-shaped parts protruding upward from a common base, air inlet tube / outlet opening (31) of each flexible air-filled bubbles (22) or selected flexible air-filled bubbles (22) can be placed in the bubble base panel (23) and protrude from the bubble downwards, instead of being in the side wall and protruding outwards from the side as shown in Figures 1 and 2A.

[0042] As shown in Figures 1, 4 and 5, the device for minimizing volumetric force (20) includes a set of force sensors (32), which has a matrix of single force sensors (33), wherein at least one sensor is located on the upper surface (28) each flexible air-filled bubble (22). According to the detailed explanation given below, each force sensor (33) is equipped with a force-responsive sensor whose electrical resistance changes inversely in proportion to the normal, i.e. perpendicular, force exerted on the sensor by an object, such as the body of a person supported by pillow cover. (21) In a preferred application example, the force sensor set (32) is held in position on the upper surface of the flexible air-filled bubbles (22) by means of a silhouette-emphasizing, waterproof adhering cover (21A) which closely adheres to the cushion and which can be removed ( 21) as shown in Figure 3.

[0043] In Figure 1, it should be noted that the device for minimizing the effect of volumetric force (20) includes an electronic control module (35). As detailed below, the electronic control module (35) is equipped with a sensor interface circuit (36) for electric interconnection of the sensors (33). The electronic control module (35) is also equipped with a computer (37) connected to the sensor interface circuit (36). The computer (37) is programmed to receive input signals from the sensor interface system (36), read the resistance of individual sensors (33) and calculate the amount of forces exerted on each sensor from it, perform calculations based on force measurements and transmit signals enabling pressure control in individual flexible air-filled bubbles (22), which are calculated according to the algorithm, to minimize the concentration of forces acting on the bubbles.

[0044] In the preferred use of the device (20), the measurement of the resistance of each sensor (33) is facilitated by placing the sensors in a matrix arrangement of rows and columns. In this setting, the individual 6 x 2 resistances of the set (32) of sensors (33) can be measured with 6-row interface wires and 2 column interface wires (50), (51) as shown in Figure 1.

[0045] In order to avoid crosstalk between individual sensor readings (33), said row-column system requires that each sensor have non-directional, asymmetrical current-voltage properties, e.g., having a diode-specific impedance. As described in detail below, the present invention includes a new sensor with the properties required for a diode. Alternatively, using force sensors (33) that do not have diode properties, the set of force sensors (32) can be divided into 12 separate rectangular sensors (33), electrically insulated from each other, with a separate pair of interface wires connected to the upper and lower electrodes of each sensor.

[0046] As shown in Figure 1, the device for minimizing the volumetric force (20) is equipped with an air pump or compressor (40) for supplying pressurized air to the inlet (42) of the manifold manifold (41). The manifold manifold (41) is equipped with 12 outlet openings (43A), each of which is connected via a valve (43) to a separate inlet of a flexible air-filled bubble (31). As described in detail below, the compressor (40), manifold manifold (41) and valves (43) are functionally connected to a computer (37) and an air pressure transducer (44). The pressure transducer (44) generates an electric signal proportional to the pressure, which is then input into the computer (37). This type of system allows the pressure reading of the inflated air in each flexible air-filled bubble (22) to be obtained separately and differentiated under the control of a computer (37).

[0047] Figures 2A, 4 and 5 illustrate the details of the construction of the force sensor set (32). As shown in these drawings, the sensor set (32) includes an upper protective sheet (45) made of thin, flexible, stretchable material. In one example of the use of the sensor kit (32) manufactured by the present inventor, the protective sheet (45) was made of a "stretch in both directions" Lycra material, whose thickness is about 0.010 inches, and the thread density is 88 threads per inch. This material had the trade name Millglass Platinum, style No. (24) 7579, and was obtained from Milliken & Company, PO Box 1926, Spartanburg, SC 29304.

[0048] Referring to Figures 4 and 5, the set of sensors (32) includes an upper columnar conductive sheet (46) which is attached to the bottom surface of the upper flexible protective sheet (45) by means of flexible adhesive tapes made of 3M 950 transfer tape or with a flexible adhesive such as Lepage latex contact adhesive. The column conductive sheet (46) is made of a matrix fabric sheet consisting of 92% nylon and 8% Dorlastan fibers, which makes the sheet flexible and stretchable in both directions. The matrix sheet of conductive sheet (46) made of material is electroless, coated with a copper backing and then with a nickel coating. Metallic coatings completely impregnate the surfaces of the fibers adjacent to the gaps of the mesh, as well as the upper and lower surfaces (47), (48) of the conductive sheet (46), thus creating electrically conductive paths between the upper and lower surfaces (47) and (48). The present inventor has found that the suitable conductive material for making the conductive sheet is material of the Woven Silver brand, catalog number A251 available from the Lessemb Company, 809 Madison Avenue, Albany, NJ 12208, USA.

[0049] In the embodiment of the sensor set (32), the upper conductive sheet (46) was made of the material described above, i.e. Woven Silver, catalog number A151 The surface resistance of the upper and lower surface (47), (48) of this material was about 1 ohm / m² or less, and the interlayer resistance between the upper and lower surfaces (47), (48) was about 50 ohm / m2.

[0050] In the preferred use of the sensor set (32) of the present invention, single conductive pads or row and column wires are formed by etching non-metallic channels vertically in the conductive sheet (46) from the top of the upper conductive surface (47) up to the bottom the lower conducting surface (48). Thus, as shown in Figure 5, the narrow, longitudinally arranged straight channels (49) are etched in the upper column conductive sheet (46). This design creates two adjacent, relatively wide electrodes, elongated along the left and right flat column electrodes (50), (51). Adjacent electrodes of the left and right columns are separated by a relatively thin channel (49), thus electrically providing insulation to adjacent column electrodes.

[0051] According to the present invention, the insulation channels (49) are etched in the upper conductive sheet (46) to form the column electrodes (50) and (51) by means of the following new process.

[0052] First, in order to prevent capillary pull-up and the resulting wetting of subsequent pickling solutions in the conductive material sheet (46), the sheet is pre-processed by treating it with a hydrophobic substance such as PTFE. The treatment is best done by spraying the conductive sheet material (46) with an aerosol containing a hydrophobic material, such as PTFE. The corresponding aerosol is sold under the Scotch Guard trade name by 3M, St Paul, Minnesota. It is recommended to secure areas of the conductive sheet material (46), including insulating channels (49), against hydrophobic treatment by means of attachment to the sheet, against the use of hydrophobic material, duct-shaped masking tape strips.

[0053] After this pretreatment of the conductive sheet (46) with a hydrophobic substance, the masking tape sheets are attached tightly to both the upper and lower surface (47), (48) of the conductive sheet, by means of a roller or a button to ensure that there are no voids between the masking tape and the surface that would allow the etching solution to reach the conductive surfaces. Then the strips of masking tape in the shape of insulating channels (49) are removed from the conductive sheet. Optionally, the masking tape strips to be removed are pre-shaped by cutting partially larger masking tape sheets.

[054] After removing from the conductive sheet (46) the strands of masking tape corresponding to the channels (49), the conductive metal coatings of the material sheet aligned with the channels are chemically etched. The preferred method of chemical etching uses a concentrated solution of 10 mg ammonium phosphate in 30 ml water. The ammonium phosphate solution is mixed with methyl cellulose powder at a concentration of 10 percent ethyl cellulose powder until a gel consistency is obtained. The etching gel thus formed is then rolled out over the upper and lower surface areas (47), (48) of the conductive sheet (46), through the channels (49). The etching gel can remain on the channels (49) for about 1 hour at room temperature, during which time the nickel and copper coating of the conductive sheet material matrix (46), in vertical alignment with the channels (49), is completely removed, thereby the channels become electrically insulating. This process divides the conductive sheet into electrodes, respectively left and right columns (50), (51).

[0055] The etching process that forms the insulation channel (49) is completed by rinsing the etching gel from the top and bottom surfaces (47), (48) the conductive sheet (46), and then removing the masking tape from the top and bottom surfaces.

[0056] Referring still to Figure 5, it should be noted that the sensor set (32) includes a thin piezoresistive sheet (52) which on the upper surface (53) in direct contact with the lower surface of the left and right columns is equipped with electrodes (50), (51). The piezoresistive sheet (52) has a lower surface (54) that is in direct electrical contact with the upper surfaces of the row electrodes on the bottom sheet of the row conductors. The lower sheet of row conductors (56) has a structure similar to the structure of the upper sheet of column conductors (46). Thus, the bottom sheet of row conductors (56) has upper and lower conductive surfaces (57), (58), and narrow, transversely located insulation channels (59), which are placed between and define the row electrodes (61), (62), ( 63), (64), (65), (66).

[0057] The function of the piezoresistive sheet (52) of the sensor set (32) is to create conductive paths between the column and row electrodes, e.g. the left column (50) electrode and the rear row electrode (61), whose resistance varies in a predetermined manner depending on from the normal force exerted on the set of sensors.

[0058] In exemplary embodiments of the sensor kit (32), a piezoresistive sheet (52) was produced by coating an extensible thin Lycra fabric sheet with a piezoresistive material. A suitable fabric sheet that forms the matrix supporting the piezoresistive material is fabric known under the trade name Platinum, Milliken Style # 247579, obtained from the manufacturer, Milliken & Company, Spartenburg, South Carolina, USA. The fiber content of the fabric was 69 percent nylon and 31 percent Spandex, the density of the thread is about 88 threads per inch, and the thickness aa 0.010 inches. The piezoresistive material used for coating the material matrix is ​​made as follows:

The graphite solution, carbon powder, nickel powder and acrylic binder are mixed in the required proportions to obtain the desired strength and piezoresistive properties. A silver-coated nickel flake is used to achieve a force response in the low force range of 0 to 1 psi, graphite is used in the medium range of 1 to 5 psi, Charcoal Lamp Black is used in the high force range of 5 to 1000 psi . Here is the description of the substance that constitutes the components of the piezoresistive material:

Silver plated nickel flake:

Plates approximately one micron thick and 5 microns in diameter.

Screening analysis (-325 grid) 95%.

Apparent density 2.8.

Microtrac d50 / microns 12-17

Available at: Novamet Specialty Products Corporation, 681 Lawlins Road, Wyckoff, NJ

07481

Graphite Powder:

Synthetic graphite, AC-4722T

Available in: Anachemia Science 4-214 DeBaets Street Winnipeg, MB R2J 3W6 Charcoal Lamp Black:

Anachemia part number AC-2155

Available at: Anachemia Science 4-214 DeBaets Street 55

Winnipeg, MB R2J 3W6

Acrylic binder:

Highly effective Staticide surface finish

P / N 4000-1 Ph 8.4 to 9.0

Available at: Static Specialties Co. Ltd. 1371-4 Church Street Bohemia, New York 11716 [0059] The following are examples of mixtures used in the production of piezoresistive materials with different sensitivities:

Example 1 for forces between 0 and 30 psi:

- 200 ml acrylic binder

- 10 ml nickel powder

- 10 ml graphite powder

- 20 ml carbon black

Example 1 for forces between 0 and -100 psi:

- 200 ml acrylic binder

- 5 ml nickel powder

- 5 ml graphite powder

- 30 ml carbon black

Example III for forces in the range of 0 to -1000 psi:

- 200 ml acrylic binder

- 1ml nickel powder

- 1 ml graphite powder

- 40 ml carbon black [0060] The material matrix of the piezoresistive sheet (52) is completely immersed in the piezoresistive coating mixture. Excess material is removed and the sheet hung and left to air dry.

[0061] Figure 6 illustrates the calculation of the minimum distance S between adjacent air filled elastic bubbles (22) and the minimum non-conductive band width (49) between adjacent sensor set wires (32).

[0062] Referring to Figure 6, it should be remembered that when the patient collapses in an air-emptied flexible bubble (22), the upper layer of the force sensor (33) decreases and moves away from the flexible bubble on which it was initially located. If the non-conductive band (49) is too narrow, it is possible that a conductor, such as a column conductor (50) located on an air-emptied elastic bubble, will contact the adjacent conductor (51) and thereby register forces that are not representative of the interacting force on the elastic bubble in which it was initially located. It is therefore necessary for the non-conductive band (49) to be wide enough to prevent this. Assuming a simple situation in which the elastic air-filled bubble is emptied of air, then the layer of force detection is reduced to a distance equal to the diagonal (C1 and C2), as shown in Figure 6, the width S of the non-conductive band (49) should be equal to or greater than ( C1 + C2 - the width of the flexible bubble) to prevent incorrect reading of forces as forces transmitted by the adjacent flexible bubble.

[0063] Figure 7 shows the electrical resistance of a one-inch piezoresistive force sensor element (48) obtained by using a piezoresistive sheet (37) with the composition mentioned for the exemplary set of sensors (32) shown in Figures 1 and 2, and made as described above, in depending on the normal force or pressure exerted on the upper surface (47) of the upper substrate sheet (33) of the sensor set (32). As shown in Figure 7, the resistance changes inversely as a function of normal force.

[0064] As shown in Figure 1, electrodes of the row (31-l) to (31-m), in a vertical arrangement with electrodes columns (32-l) to (32-n) form with a sheet of piezoresistive layer (37) between the electrodes columns and row, rectangular matrix set am X n force elements m X n (48). If the upper and lower electrodes for each sensor element (48) were electrically insulated with a separate pair of lead-out wires for each of the 12 sensors, we have 24 lead-out wires in total.

[0065] Preferably, as shown in Figures 1 and 5, the set of sensors is arranged in rows and columns, and therefore requires only 8 output guides. However, as shown in Figure 10A, if the addressing matrix of a set of sensors (32) is used to measure the resistance of individual sensors (33) to thus determine the normal forces exerted on the sensors, there is a significant crosstalk between resistance on the addressed sensor (33) and unaddressed sensors due to parallel current paths to unaddressed sensors. To solve the crosstalk problem, the present inventor has developed a method of modifying sensors (33), to give them the properties of a diode. How can you confirm by referring to the Drawing. 10B, crosstalk between sensors (33) that have a non-reversible, polarization-sensitive transfer function, alleviates the crosstalk problem present in the matrix of symmetrically conductive sensors (33) shown in Figure 10A.

[0066] The sensors (33) are modified to obtain the diode property by modifying the production of the piezoresistive layer sheet (52) as follows: First, the piezoresistive layer sheet (52) is prepared as described above. Then, the top surface (69) or bottom surface (70) of the piezoresistive coating (67) of the piezoresistive sheet (52) is modified to form a semiconductor type PN junction on it.

[0067] The modification of the piezoresistive coating (67) to create the PN junction is first carried out by preparing a suspension which has the composition of one of the three exemplary mixtures described above, but modified by adding 5 ml of each copper oxide (CuO) as a fine powder with particle size 50 microns, and 5 ml cuprous oxide (Cu₂O) in the form of a fine powder with particles of 50 microns and thorough mixing of the above ingredients. The resulting solution is then reduced by stopping about 30 mg sodium borohydride solution, also known as sodium tetrahydroborate (NaBH₄) or ammonium phosphate to form a solution with a pH of about 5.5. The solution is then applied to the upper (69) or lower surface (70) of the piezoresistive coating (68) of the piezoresistive sheet (52). This coating process is carried out by means of a roller, which means that about 0.5 ml of solution per square centimeter is used. The surface coating is then allowed to air dry at room temperature and relative humidity less than 20% for 4 hours. After drying, the coated surface acts as a P-type semiconductor and the uncoated side of the coating (68) acts as a N-type semiconductor of the PN diode connector .

[0068] Figure 8 illustrates a sensor (33) that has been prepared as described above to obtain a sensor with diode properties and a circuit to obtain the transfer function of sensor IV (current against voltage). Figure 9 shows a typical IV curve for the sensor (33) in Figure 8.

[0069] As stated above, the advantage of modifying the sensors (33) by adding a semiconductor layer that acts like a diode is that the crosstalk between sensors decreases. As shown in Figure 10A, this crosstalk occurs because of the so-called "square fill" phenomenon, in which three connections are made in a square matrix set of three non-directed resistors that form three square angles. Thus, any two connections in a vertical column, and the third in the same row act as a combination in the set of XY conductors. The resistor in the fourth corner of the square appears as a phantom in parallel with the addressed resistor, because the current can flow backwards through this resistor, and forward through other resistors. Additional efforts should be made and additional expenses related to electronics to eliminate the participation of this phantom. For example, as shown in Figure 10A, if potential V conductors were used between the XiYi row and column conductors to thus determine the resistance of the piezoresistive resistance of the sensor R_cii), the reverse current flow through the "phantom" resistor R (22) would cause the sum of resistance Ri₂ + R_C22) + R22 for Rii anastomosis, causing parallel current flow indicated by arrows in Figure i0A, which in turn would be the cause of the following incorrect resistance values:

Rxiyi = Rii // (Ri2 + [R22] + R2i), Rxiyi = Rii (Ri2 + [R22] + R2i) / (Rii + Ri2 + [R22] + R2i), where the brackets at the resistance value indicate counterclockwise flow current through this resistor rather than clockwise i.e. slanting down to the left. So, for example, if each of the four resistances listed above had an i0 ohm value, the measured Rii would be:

Rii = i0 (i0 + i0 + i0) / (i0 + i0 + i0 + i0) = 300/40 = 7.5 ohms, i.e. 25% below the actual value, i0 ohms Rii. If each of the Ri2, R22 and R2i resistance values ​​from the three unaddressed piezoresistive sensors (33) were lower, e.g. was i ohm, due to higher forces focused on these sensors (33), the measured value of Rii would be:

Rii = i0 (i + i + i) / (i0 + i + i + i) = 30 / i3 = 2.3i oma, i.e. a value about 77 percent lower than the actual value of Rii.

On the reverse side, by placing the diode in line with each element of the piezoresistive sensor (33), as shown in Figure iB, the electrical resistance of the element measured in the counterclockwise counterclockwise flow of the test current through the sensor element, e.g. R22, for practical reasons, would be arbitrarily large or infinite compared to the current paths flowing clockwise through the remaining resistances shown in Figures i0A and i0B. In this case, the value of the measured resistance for a 2x2 matrix of four resistances each with an i0 ohm value would be:

R_x1y1 = 10 (1 + ^ + 1) / (10 + 1 + ^ + 1) = 10 ohms, correct value.

Thus, modifying each sensor element 33 to include the pn connector, thereby giving the sensor element the properties of a diode, electrically insulates, i.e., prevents backward current flow through each sensor element (33). Thanks to this, each sensor element (33) has the correct value of the electrical resistance Rxy, and thus the forces exerted will be accurately measured by means of a matrix of rows and columns addressing, and not demanding a separate pair of conductors for each sensor element.

[0071] The above described elements of the force minimizing device (20) of the present invention are connected to each other to form a closed servo circuit. This system is effective in reducing volumetric force using an algorithm in accordance with the method of the present invention. Understanding this method and device can be facilitated by referring to Figure 11, which shows a block diagram of an electropneumatic system element of the device controller (20A), in combination with a schematic view of the device shown in Figure 1 and a perspective view shown in Figure 5.

[072] Referring to Figure 1, it can be seen that the electropneumatic controller device (20A) includes a computer (37) that is connected bidirectionally to a set of force sensors (32) through a force sensor interface module (36). The sensor interface module (36) includes an analog-to-digital converter (DAC) (71) to generate, in response to control signals from the computer (37), test voltage or currents that are directed to individual force sensors (33) of the addressing matrix.

[0073] Single force sensors (33) are addressed by connecting one terminal of the current source or voltage of the source controlled by the DAC (71) to one selected from X conductors of the order 1-6 by the multiplexer X (72) and connecting the other source terminal to one selected of the Y conductors of columns 1 or 2 through the Y multiplexer (73). The sensor interface module (37) also includes an analog-to-digital converter (ADC) (74), which uses a sensor (33) to measure the voltage or current drop resulting from the application of a test current or voltage, and entering the measured value into the computer (37). Using predetermined scale factors, the computer (37) calculates the instantaneous value of the electrical resistance of the selected addressed sensor (33), and from this resistance value the corresponding normal force immediately exerts on the addressed sensor.

[0074] In response to control signals cyclically issued by the computer (37), the X multiplexer (72) and the Y multiplexer (73) are used to cyclically measure the resistance of each element of the force sensor (33), at a relatively fast rate, 3000 samples per second , enabling the computer (37) to calculate the force exerted on each force sensor (33) at this sampling rate.

[0075] Referring still to Figure 11, the device (20) is equipped with a pressure control module (75) for dynamically controlling the air pressure in each flexible air-filled bubble (22) in response to control signals issued by the computer (37) ), based on the force value measured by the set of sensors (32) and the algorithm programmed in the computer. As shown in Figure 11, the pressure control module (75) is functionally connected to an air compressor (40) and an air pressure transducer (44) at the compressor outlet (76) to compress the air in the outlet to a computer controlled value (37).

[0076] The outlet (76) of the compressor (40) is connected to the inlet (42) of the manifold with 12 outlet (41). In response to the electric control signals emitted by the computer (37) and passing through the pressure control module (75), each of the 12 individual inlet manifolds of an elastic air-filled bubble (43) connected to a separate outlet (43A) of the collector (41) can be controlled individually.

[0077] In the first open position of the distributor valve (43), the air inlet opening (31) of the selected flexible air-filled bubble (22) is subjected to pressure measured by the transducer (44) to a predetermined value by switching on the compressor (40) to thus inflate the bubble to the desired pressure level. Alternatively, when the compressor (40) is turned off, the bleed valve (77) connected to the intake inlet (42) of the collector (41) can be opened to deflate the flexible air-filled bubble (22) to the lower pressure by letting the air out.

[0078] After opening one of the 12 distribution valves (43) in response to the control signal from the computer (37), for a period sufficient to inflate the selected air-filled elastic bubbles (22) to a predetermined pressure, the electrical signal output via a pressure transducer (44 ), which is proportional to the pressure in the elastic bubble and the entry to the computer (37), leads to the computer issuing a control signal to the valve to close it and a control signal to the compressor (40) to turn it off.

[0079] When the vent valve (77) and the selected distribution valve (43) open in response to the control signal from the computer (37) to deflate the air-filled elastic bubble (22) to the lower, predetermined pressure, the electrical input from the pressure transducer (44) to the computer (37) leads to the computer issuing a control signal about electric closing. This control signal closes the vent valve (77) and the open distribution valve (43), thus maintaining the selected bottom pressure in the selected flexible bubble of an air-filled flexible bubble. Similarly, the air pressure in each flexible air-filled bubble (22) is sequentially adjusted by sending a control signal to the distributor valve (43) to open the valve and turn on the compressor (40) and / or the vent valve (77) to introduce and release. air to and from a flexible air-filled bubble until a predetermined pressure is reached.

[0080] Figure 12 is a simplified perspective view of the preferred embodiment of the electropneumatic device housing (20A) shown in Figure 11 and described above. As shown in Figures 11 and 12, the electropneumatic controller (20A) includes an operator interface module (78). The operator interface module (78) includes manual control, including multi-functional on / off control mode switches. (on / off), and button (79), data entry buttons (80), (81), as well as a digital display (82). The display (82) is controlled by a button (79) to selectively display air pressure and the force exerted on selectively flexible air-filled bubbles (22) and the sum and average of all forces exerted on the sensors (33).

[0081] As shown in Figure 12, the electropneumatic controller (20A) is preferably located in a box-shaped housing (83) equipped with an L-shaped handle protruding from the rear wall (84) to hang the housing on the side or rear wall bed. The housing (83) of the electropneumatic controller (20A) is also equipped with a cylindrical member (86) for connecting air ducts (87) with flexible air-filled bubbles (22), row and column guides (88), (89) with sensors (33) a set of sensors (32), and an electric power cord (90) with a source of electricity to provide power to the device components (20A).

Algorithm for minimizing force [0082] The adaptive cushion device for minimizing force (20) as described above includes a cushion (21) equipped with a plurality of flexible air-filled bubbles (22). Each flexible bubble (22), on its upper surface, is equipped with a separate force sensor (33) from the set (32) of force sensors. The air pressure transmitter (44) is used to measure the air pressure in each flexible bubble (22). Each force sensor (33) is in a region of potential contact with a person lying on the cushion (21) with a flexible air-filled bubble (22). Each piezoresistive force sensor (33) acts as a sensitive force transducer whose electrical resistance is inversely proportional to the maximum force exerted by the human body on the flexible bubble (22), the maximum force corresponds to the lowest resistance path in any part of the sensor.

[0083] In the application of the pillow adaptation device (20) in accordance with the present invention and Figures 1 and 3, the pillow is divided into a pair of left and right longitudinally arranged columns. The columns are in turn divided into six longitudinal zones, each of which is equipped with a pair of flexible bubbles filled with air, left and right, providing support to the next longitudinal zone of a person, e.g. head, hips or heels. Thus, as shown in Figure 3, each column has 6 flexible air-filled bubbles (22), e.g. a flexible left-hand column bubble (22L1) - (22L6). The air pressure in each of the 12 chambers (22L1) - (22L6), (22R1) - (22R6) is separately controlled by a compressor (40) and distribution valves (43) in response to measurements made with force sensors (33). The pressure in individual flexible air-filled bubbles (22) is controlled by the electropneumatic controller system (20A) using a new algorithm introduced into the computer (37) as described, which will now be given.

[0084] There may be at least one zone using one flexible air-filled bubble (22) and up to N zones using flexible air-filled bubbles, each zone equipped with a force sensor (33) for measuring the maximum force acting on a given flexible air-filled bubble , a pressure transducer (44) used to measure the air pressure in a given air-filled flexible bubble. The control algorithm is in continuous iteration, whereby force sensors (33) determine the peak force exerted on the patient's body, and the pressure transducer (44) measures the air pressure at which peak force occurs. At the end of the force sampling cycle on all sensors, the air pressure in each flexible air-filled bubble (22) is restored to a pressure at which force has been minimized for all zones. During this process, the apparatus constantly searches for the optimal pressure of individual flexible bubbles, which leads to the minimization of the peak forces acting on the person supported by the cap (21).

Algorithm description [0085] Data:

N zones numbered from one to N, each containing one flexible air-filled bubble (22)

The flexible air-filled bubble of each zone is selectively connected to an air pressure transducer (44) to measure P #. All flexible air-filled bubbles (22) are equipped with single force sensors (33) capable of measuring the maximum force F # exerted on the surface of each flexible bubble.

[0086] The compressor (40) sends air at a pressure of up to 5 psi to selected individual flexible bladders of the air-filled zones (22). There is a normally closed vent valve (77) to deflate the selected flexible air-filled bubble (22) by venting the air outside through the vent valve.

[0087] There are many distributor valves (43) that select into which flexible air-filled bubbles (22) air is introduced or from which the air is deflated by deflating the air through the vent valve (79).

Algorithm stages [0088]

1. Pset :::: Pset, start, close the vent valve (77)

2. Select zone i = 1 by opening the distribution valve (43-1)

3. Turn on the compressor (40).

4. Measure the air pressure in the air-filled elastic bubble (22) in zone I

5. Compress the air in the elastic bubble filled with air (22) from zone I to the pre-set upper pressure level and close the distribution valve (43-1) Pset value.

6. Repeat for i + 1 until i + 1 = N

7. Select zone i = I

8. Obtain force sensor readings (33) for all zones. 50

9. Open the vent valve (77)

10. Bleed the air from the flexible air-filled bubble (22) from zone one to the predetermined minimum pressure level and monitor the readings of all force sensors (33) exerted on all the air-filled flexible bubbles (22). Maintain the pressure in the remaining air-filled flexible bubbles (22) at the upper pressure level settings.

11. Measure the forces acting on all flexible air-filled bubbles (22) when emptying a single flexible air-filled bubble from zone one and calculate the sum and optionally the average of all force sensor readings (33).

12. In the computer memory (37) record the measurement of the pressure of the flexible air-filled bubble (22) from the first zone, in which the minimum sum and optionally the average of all force sensor readings (33) are obtained.

13. Restore pressure in the flexible bubble filled with first zone air (22-1) to the value where the minimum sum and average force sensor readings were obtained for all force sensors.

14. Close the diverter valve from zone one (43-1). Maintain pressure in zone one

15. Set: Counter = I + 1.

16. Repeat steps 2 to 15 until counter = i + 1 = N

17. Set: Pset = Pset, start - (Counter * 20% _ (i.e. reduce the output pressure in the flexible bubble of the first zone (22-1)).

18. Repeat steps 2 to 16 (i.e. with reduced outlet pressure). Reservation

19. All force sensors (33) should be constantly monitored and if a significant change is detected (Delta F> 0.2 * F #) (transferred patient), start from the beginning, from Stage 1.

[0089] Figure 13 shows the device sequence diagram (20) using the algorithm described above. Table 1 shows the respective lower and upper output pressure levels for the chambers (22), depending on the weight of the patient or other person supported by the pad cushion (21) of the device.

TABLE 1

<td>Patient's weight</td><td>Minimal pressure</td><td>Output pressure</td>

<td>75-119 pounds</td><td>5.5 "± 0.7: H2O 10.31 ± 2mm Hg</td><td>6.5 "± 0.7: H2O 12.18 ± 2mm Hg</td>

<td>120-164 pounds</td><td>6 "± 0.7: H2O 11.25 ± 2mm Hg</td><td>8 "± 0.7: H2O 15 ± 2mm Hg</td>

<td>165-199 pounds</td><td>8 "± 0.7: H2O 15 ± 2mm Hg</td><td>1 0 "± 0.7: H2O 18.75 ± 2mm Hg</td>

<td>200-250 pounds</td><td>10 "± 0.7: H2O 18.75 ± 2mm Hg</td><td>12 "± 0.7: H2O 22.49 ± 2mm Hg</td>

<td>Maximum pressure</td><td></td><td>26 "± 0.7: H2O 48.74 ± 4mm Hg</td>

[0090] In the variant of the method and application of the device according to the present invention and the above description, after optimizing the pressure in the individual air-filled flexible bubbles (22) to obtain a minimum concentration of force, the inlet pipes (31) can be closed permanently and the adaptation cushion ( 21) can be permanently disconnected from the pressure control module (75). This variant will also allow the production of custom cushions (21), using flexible air-filled bubbles (22) to adjust the chair cushion to minimize the concentration of force on a specific person. Similarly, a variant of the method and use of the device according to the present invention can be used to adapt a saddle seat or car seat.