WO1998041126A1

WO1998041126A1 - Passive pressure control of seat cushion and back for airline seat

Info

Publication number: WO1998041126A1
Application number: PCT/US1998/005154
Authority: WO
Inventors: Anthony R. Ii Haba
Original assignee: Mccord Winn Textron Inc.
Priority date: 1997-03-18
Filing date: 1998-03-17
Publication date: 1998-09-24

Abstract

A seat assembly (20, 20d, 20e, 20f) for mounting within a cabin of an aircraft comprises a seat surface (32) configured to receive and support at least a portion of the body of a human occupant. An air cell module (34, 34a, 34b, 34c, 34d, 34e, 34f) supported adjacent to the seat surface (32) includes an inflatable bladder (36, 36a, 36b, 36c, 36d, 36e, 36f) having a variable air cell firmness value. The air cell firmness value increases as the ratio of bladder air pressure to cabin pressure increases. The air cell module (34, 34a, 34b, 34c, 34d, 34e, 34f) also includes an air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e, 38f) configured to control air cell pressure. The air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e, 38f) is configured to use cabin pressure changes in providing desired air cell firmness.

Description

PASSIVE PRESSURE CONTROL OF SEAT CUSHION AND BACK

FOR AIRLINE SEAT

TECHNICAL FIELD

This invention relates generally to vehicle seats and more particularly to vehicle seats having pressure controlled air cells in the seat cushion and seat back for supporting the seat occupant comfortably.

INVENTION BACKGROUND

Air cell assemblies are incorporated into vehicle seats to increase seat occupant comfort by allowing seat occupants to adjust seat configurations to accommodate each occupant's unique physical characteristics. However, air cell assemblies for aircraft seats are affected by significant cabin pressure changes that occur even in large pressurized commercial aircraft. The cabin pressurization system of a commercial airliner must provide sufficient air pressure to maintain a cabin pressure altitude of less than 10,000 feet, i.e., the air pressure experienced at 10,000 feet above mean sea level (MSL). Cabin pressure altitudes must be maintained at less than 10,000 feet to conform to FAA regulations and to prevent passengers and crewmembers from becoming hypoxic. To maintain appropriate cabin pressure, airliner cabin pressurization systems are programmed to follow cabin pressurization schedules that allow cabin pressure altitude to increase with increasing aircraft altitude up to approximately 6000 feet MSL. The pressure differential required to maintain a cabin pressure altitude of 6000 feet at a cruising altitude of 35,000 feet MSL is approximately 8.2 psi. Pressure differentials of this magnitude can over-inflate or even rupture the air cells of conventional automotive pneumatic air cell systems.

Several types of air cell assemblies are already known for use in land vehicles. For example, U.S. Patent Number 4,444,430 granted April 24, 1984 to Youki Yoshida and Kenji Ichikawa discloses an automotive seat that has a pneumatic component in the form of an air cell type lumbar support that is embedded or housed in the lower portion of a seat back. The air cell is pressurized to provide a seat occupant with a desired degree of firmness and support. Air cell firmness is increased by increasing air cell pressure. Air cell pressure is increased by manipulating a handle or lever that expands and contracts a manual pump that is fixedly mounted in a space in the upper portion of the seat back. Air cell pressure and firmness are decreased by pushing a button in the end of the lever that, in turn, opens a vent. U.S. Patent Number 4,722,550 granted February 2, 1988 to

Naohiro Imaoka and Hitoshi Nakashima discloses an automotive seat having air cells in the seat cushion and the seat back. An air pump supplies air to the air cells to increase air cell firmness. The air pump is mounted on a frame within the seat back and is connected to each of the air cells by an air supply means and a main air pipe. The firmness of each air cell can be controlled manually by a manual operation switch or automatically by speed and steering angle sensors and a controller.

U.S. Patent Number 4,840,425 granted June 20, 1989 to Roger H. Noble discloses a cushioned seating assembly that includes a seat support cushion and a back support cushion. The assembly also includes a control assembly that controls inflation and at least partial deflation within the cushioned support assembly through supply/exhaust lines. The cushioned seating assembly may be used in association with existing power and fluid pressure sources or in association with an internal power fluid pressure source. This latter alternative includes an electric motor driven air compressor and a solenoid air valve.

U.S. Patent Number 5,529,377 issued June 25, 1996 to Miller discloses an air cell assembly or module mounted on a backplate or other suitable support of an automotive seat back. The module includes an air cell, an electric motor driven air pump and a. solenoid valve. The pump is disposed inside the air cell and is operatively connected to an air tube that extends out of the air cell. The solenoid valve is connected to the exterior end of the air tube to control the flow of air to and from the air cell.

None of the above patents discloses an air cell system that can either make use of or compensate automatically for changes in ambient air pressure. Therefore, what is needed is an air cell assembly for aircraft seats that includes a pressure regulating system that takes into account cabin pressure changes.

INVENTION SUMMARY

An occupant support assembly (20) for mounting within a cabin of a vehicle, the cabin including a cabin atmosphere having a cabin air pressure value. The assembly (20) comprises a seat surface (32) configured to receive and support at least a portion of the body of a human occupant and a first air cell module (34, 34a, 34b, 34c, 34d, 34e) supported adjacent the seat surface (32). The first air cell module (34, 34a, 34b, 34c, 34d, 34e) includes an inflatable bladder (36, 36a, 36b, 36c, 36d, 36e) having a variable air cell firmness value that increases as the ratio of air cell pressure to cabin pressure increases. The air cell module (34, 34a, 34b, 34c, 34d, 34e) also includes an air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e) configured to control air cell pressure. The improvement comprises the air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e) being configured to use cabin pressure changes in providing desired air cell firmness, the cabin pressure decreasing with increasing aircraft altitude.

Unlike prior art air cell assemblies for vehicle seats, the present invention provides an occupant support assembly (20) configured to use cabin pressure changes to maintain air cell firmness.

BRIEF DRAWING DESCRIPTION

To better understand and appreciate the invention, refer to the following detailed description in connection with the accompanying drawings: Figure 1 is a sectional side view of an aircraft seat having a seat back and cushion equipped with pressure controlled air cells in accordance with the invention;

Figure 2 is an enlarged view of a typical air cell module; and Figure 3 is a plan view of a typical air cell arrangement for an aircraft seat cushion;

Figure 4 is a diagrammatic view of a piezo-electric pressure sensor included in the air cell module of Fig. 2;

Figure 5 is an alternative air cell module construction including open-cell foam;

Figure 6 is an alternative air cell module construction including only two valves;

Figure 7 is an alternative air cell module construction including open-cell foam and no mechanical pump; Figure 8 is a cut-away perspective view of the air cell module of

Fig. 7 exposing an array of piezo-electric sensors embedded in the open- cell foam;

Figure 9 is a diagrammatic representation of an air cell zone comprising five interconnected air cell modules and sharing a common air cell firmness regulator;

Figure 10 is a diagrammatic representation of three air cell zones interconnected by a common manifold and sharing a common air cell firmness regulator; and

Figure 11 is a diagrammatic representation of an air cell zone comprising five interconnected air cell modules having individual pressure relief valves.

PREFERRED EMBODIMENT DESCRIPTION

An occupant support assembly for mounting within a cabin of a vehicle is generally shown at 20 in Figure 1. The assembly 20 comprises an aircraft passenger seat generally indicated at 22 in Figure 1. The aircraft passenger seat 22 includes a seat back 24 and a seat cushion 26. The seat back 24 and seat cushion 26 are supported on a metal frame 28. An air storage plenum 30 is included in the seat back 24. The seat 22 has a seat surface 32 extending across the seat cushion 26 and seat back 24. The seat surface 32 is configured to receive and support at least a portion of the body of a human occupant. The cabin includes a cabin atmosphere, i.e., a body of air, having a cabin air pressure value.

The assembly 20 also includes ten air cell modules generally indicated at 34 in Figures 1, 2 and 3. The air cell modules 34 are supported adjacent the seat surface 32. Each air cell module 34 includes an inflatable bladder 36 having a variable air cell firmness value. The air cell firmness value of an air cell bladder 36 is the ratio of air cell pressure to cabin pressure. Therefore, the air cell firmness value of a given air cell module 34 increases as the ratio of air cell pressure to cabin pressure increases. The air cell pressure is the air pressure within the air cell module bladder 36.

Cabin pressure is the air pressure in the aircraft that surrounds the air cell modules 34 and is applied to an exterior surface of each air cell bladder 36.

The air cell module 34 includes an air cell firmness regulator generally indicated at 38 in Figure 2. The air cell firmness regulator 38 is configured to control air cell bladder firmness by controlling the ratio of air cell pressure to cabin pressure.

The air cell firmness regulator 38 is also configured to make use of cabin pressure changes in providing desired air cell firmness. The air cell firmness regulator 38 either changes air cell pressure to reach a desired firmness value or maintains air cell pressure at a desired value as the cabin pressure-altitude changes. For example, the air cell firmness regulator 38 is configured to increase air cell firmness by allowing cabin pressure to decrease. Once the aircraft has reached cruising altitude and cabin pressure stops decreasing, the air cell firmness regulator 38 uses the relatively low cabin pressure to maintain a desired air cell firmness value. If air cell firmness should ever exceed a predetermined desirable value, the regulator 38 decreases air cell firmness by opening the relief valve when cabin pressure is less than air cell pressure. The system is configurable to maintain a desired air cell firmness value in either a pressurized or an un-pressurized aircraft. Additionally, the firmness regulator 38 operates in conjunction with a bellows pump 50 to supplement air cell pressure. The seat back 24 and the seat cushion 26 are each equipped with an array 44 of five of the air cell modules 34. The seat cushion 26 and the seat back 24 each include a foam bun 40, 42 typically made of elastomeric polyurethane foam material. The air cell modules 34 are mounted on the foam buns 40, 42 of the seat cushion 26 and seat back 24. A typical self-contained air cell module 34 is shown in Figure 2.

The occupant support assembly 20 includes a plurality of these air cell modules 34 disposed in an air cell array. The air cell array, generally indicated at 44 in Figure 3, is configured to enhance seat occupant comfort. In other words, the air cell modules 34 in the air cell array 44 are positioned at locations within the seat 22 where occupants typically require either additional support or load distribution. A typical pattern for an array 44 of several self-contained air cell modules 34 in the seat cushion 26 is shown in Figure 3. Five modules with a center module and a module in each corner quadrant are shown in Figure 3. The number of air cell modules 34 and the arrangement of the air cell modules 34 within an array can be varied to obtain the desired comfortable support effect for the seat occupant.

As is best shown in Figure 2, each air cell bladder 36 is hollow and includes an interior cavity 46 defined by an inner surface of a sealed plastic bladder wall 48. An exterior surface of each bladder wall 48 has a rounded circular disc-shape. In other embodiments, the bladders may be of any shape to include rectangular. The bladders may also have irregular, body-conforming shapes.

A manually actuated cylindrical mechanical bellows pump, generally indicated at 50 in Figure 2, is bonded to a circular bottom portion 52 of the bladder wall 48. The bellows pump 50 is concentrically disposed on the bottom portion 52 of the bladder wall 48 and defines a pump chamber 54 between the bellows pump 50 and the bladder wall 48. The bellows pump 50 is sealed to the bladder wall 48 to prevent air from escaping and, as is explained in greater detail below, is operative to supply air to the air cell bladder 36.

Alternative embodiments of the air cell module are generally shown at 34a, 34b and 34c in Figures 5, 6 and 7, respectively. Reference numerals with the suffix "a" in Figure 5, the suffix "b" in Figure 6 and the suffix "c" in Figure 7 designate the alternative configuration of each element common to the embodiment of Figures 1-3. Unless the description indicates otherwise, where the description uses a reference numeral to refer to an element in Figures 1-3, I intend that portion of the description to apply equally to elements in Figures 5-7 indicated by the same reference numeral with the suffix "a", "b" or "c", respectively.

The air cell firmness regulator 38 is configured to cooperate with an aircraft pressurization system in controlling air cell firmness. Aircraft pressurization systems typically allow cabin pressure to decrease according to a predetermined pressurization schedule as aircraft pressure altitude increases.

Aircraft pressure altitude is a measurement of aircraft altitude above mean sea level based on the pressure of the air surrounding the aircraft and a standard atmospheric pressure lapse rate. The air cell firmness regulator 38 includes a pressure relief valve, shown at 56 in Figure 2, and a controller generally indicated at 58 in Figure 2.

The controller 58 includes a microprocessor, shown at 60 in Figure 2. The pressure relief valve 56 is mounted in and extends through a lower portion of a bladder wall 48 of the air cell module. The microprocessor 60 is mounted adjacent the pressure relief valve 56.

The microprocessor 60 is programmed to open the relief valve 56 and to allow fluid communication between the interior cavity 46 of the air cell module bladder 48 and the cabin atmosphere. The relief valve 56 opens and closes in response to control signals from the microprocessor 60 to regulate air cell firmness. The microprocessor 60 is programmed to increase air cell firmness by closing the relief valve 56 as cabin pressure decreases. The microprocessor 60 is also programmed to decrease air cell firmness by opening the relief valve 56 when cabin pressure is less than air cell pressure.

In general, the controller 58 will allow fluid communication by opening the pressure relief valve 56 when cabin pressure is higher than or generally equal to the air cell pressure, i.e., when the aircraft is on the ground. The controller 58 will stop fluid communication by closing the pressure relief valve 56 when cabin pressure decreases below air cell pressure, i.e., when the aircraft is airborne.

The controller 58 also includes a cabin air pressure sensor or transducer 62. The cabin air pressure sensor 62 is connected to the microprocessor 60 and configured to sense cabin pressure. The controller 58 also includes an air cell pressure sensor 64 or transducer connected to the microprocessor 60 and configured to sense air cell pressure. The microprocessor 60 is programmed to control air cell firmness by modulating the pressure relief valve 56 in accordance with feedback inputs received from the pressure-sensing transducers 62, 64. The pressure sensors 62, 64 each include a piezoelectric element 66. As shown in Fig. 4, the piezoelectric element 66 of each pressure sensor 62, 64 is supported such that increases in air cell pressure result in element deflection. Element deflection generates a current by which pressure changes can be measured. The air cell firmness regulator 38 also includes an electrical power source generally indicated at 68 in Figure 2. The electrical power source 68 includes a piezoelectric element 70 that is connected to the microprocessor 60 and provides electrical power to the microprocessor 60 and the relief valve 56. The piezoelectric element 70 of the electrical power source 68 is mounted in the bladder wall 48 of the air cell module 34. More specifically, the piezoelectric element 70 is embedded in a top portion of the bladder wall 48 of the air cell module 34. Electronic control circuitry such as the microprocessor 60 may also be embedded in the bladder wall 48.

A small watch type battery 72 is mounted on the bladder wall 48 of the air cell module 34. The battery 72 is connected to the microprocessor 60 and the piezoelectric element 70. The battery 72 stores electrical power received from the piezoelectric element 70 and provides electric power to the microprocessor 60 and the relief valve 56.

A seat occupant sensor, shown at 74 in Figure 2, and a landing sensor, shown at 76 in Figure 2, are connected to the microprocessor 60.

The seat occupant sensor 74 is configured to emit an electrical signal when the seat assembly 20 is bearing the weight of an occupant. The landing sensor signals the microprocessor 60 when the aircraft is positioned on the ground. The microprocessor 60 is programmed to prevent the pressure relief valve 56 from opening when signals from the seat occupant sensor 74 and landing sensor indicate that the seat 22 is occupied and the aircraft is on the ground. This allows the air cell modules 34 to fill with air when the aircraft is on the ground while keeping the air cell modules 34 from collapsing when the aircraft is on the ground and someone is occupying the seat 22. The air cell modules 34 must maintain sufficient volume to allow the air cell modules

34 to retain a sufficient quantity of air while the aircraft is on the ground.

The piezoelectric element 70 that powers the microprocessor 60 is also configured to sense the presence of a seat occupant. When so configured, the piezoelectric element 70 generates an electrical signal in response to deflection of a metallic piezoelectric strip of the sensor due to pressure applied by the body of a seat occupant to the strip.

The landing sensor 76 includes the cabin air pressure sensor 62 and the microprocessor 60 programmed to sense an aircraft landed condition. More specifically, the microprocessor 60 is programmed to sense an aircraft landed condition when the cabin air pressure increases to within a predetermined range of the atmospheric pressure at mean sea level. As shown diagrammatically in Figure 5, the landing sensor may alternatively include a landing gear squat switch 78 connected to the microprocessor 60. The landing gear squat switch 78 is a switch typically mounted on one of the two main landing gear trucks 80 of an aircraft. The squat switch 78 is positioned to actuate when the weight of the aircraft compresses a landing gear shock strut 82 after the aircraft wheels 84 have contacted a runway. In each air cell module, electrical current paths in the form of wires 86 extend from the microprocessor 60 to the pressure relief valve 56, the pressure sensors 62, 64, and the battery 72 and the piezoelectric element 70 of the electrical power supply 68. As shown in the illustrated embodiment, the wires 86 can be integrated or embedded in the bladder wall 48 of the air cell module 34. However, if desired, the wires 86 can be provided in wiring cables such as flex cables that are exteriorly or interiorly located vis-a-vis the bladder 36.

The air cell firmness regulator 38 includes the mechanical bellows pump 50 to supplement air cell pressure gained from altitude. The mechanical bellows pump 50 is configured to increase air pressure within the air cell modules 34 in response to seat occupant movement. The pump 50 is positioned and configured to force air into the air cell bladder 36 when an occupant compresses the bellows by either sitting down in the seat or by moving and shifting in the seat after sitting down.

The bellows pump 50 is fluidly connected to the interior cavity 46 of the air cell bladder 36 by a first or upper one-way valve shown at 88 in Figure 2. The first one-way valve 88 permits air to be pumped from the bellows pump 50 into the air cell module 34. The bellows pump 50 also includes an inlet that is closed by a second one-way valve 90 that permits air to flow into the bellows pump chamber 54 from the cabin atmosphere. In the embodiment of Figures 1-3, the one-way valves 88, 90 are not connected to the microprocessor 60. However, in other embodiments the microprocessor 60 may also be programmed to maintain air cell pressure by signaling these one-way valves 88, 90 to open and close in response to inputs from an air cell pressure sensor 64.

The pumping action of a mechanical bellows pump is well known. The one-way valve 90 at the bellows inlet allows air to be drawn into the bellows pump 50 whenever outside air pressure is greater that pressure inside the bellows pump 50 or whenever the bellows pump 50 is expanded.

When the bellows pump 50 is compressed, air is forced from the bellows pump 50 into the interior cavity 46 of the air cell bladder 36 through the upper one-way valve 88 until the pressure equalizes.

According to the air cell module embodiments of Figs. 5 and 7, open-celled memory foam 92, 92c is used to fill the interior cavity 46a, 46c of each air cell module bladder 36a, 36c. Open celled memory foam 92 is a type of foam that will return to its original shape following compression. Filling the interior cavity 46a, 46c of the air cell module bladder 36a, 36c with this type of foam 92 causes the air cell module bladder 36a, 36c to fully expand when there is no seat occupant and cabin pressure is equal to or greater than air cell pressure. This is especially important when the aircraft is on the ground because a collapsed air cell module bladder 36a, 36c will not contain a sufficient volume of air to inflate the bladder 36a, 36c when cabin pressure falls during aircraft climb-out.

According to the air cell module embodiment 34b of Fig. 6, the air cell firmness regulator 38b of the air cell module 34b may include a first or upper 2-way air valve 94 disposed in the bladder wall 48b of the air cell module. The upper 2-way air valve 94 is positioned to allow fluid communication between the interior cavity 46b of the air cell module bladder 36b and a pump interior chamber 54b of the air cell module 34b. In addition, a second or lower 2-way air valve 96 is disposed in a pump exterior wall 98 of the air cell module. The second 2-way air valve is positioned to allow fluid communication between the pump interior chamber 54b of the air cell module bladder 36b and the cabin atmosphere. A microprocessor 60b is programmed to control air cell firmness by opening and closing and controlling direction of airflow through the upper and lower 2-way valves 94,

96 in response to inputs from pressure sensors 62b, 64b, 70b.

To increase air cell firmness as cabin pressure decreases during aircraft climb-out, the microprocessor 60b closes at least the upper 2-way valve 94. To increase air cell firmness through the mechanical bellows pump 50b, the microprocessor 60b opens the 2-way valves 94, 96 in the inward direction only. This allows subsequent pump compressions to force air from the pump chamber 54b into the inner cavity 46b of the air cell module bladder 36b through the upper 2-way valve 94. Whenever the bellows pump 50b returns to its uncompressed position, it will allow air to be drawn into the pump chamber 54b via valve 96 from the cabin atmosphere. To decrease air cell firmness the microprocessor 60b opens both 2-way valves 94, 96 in the outward direction to allow higher pressure air to exhaust from the inner cavity 46b of the air cell module bladder 36b to the cabin atmosphere via valves 94, 96.

The air cell module embodiment 34c of Figure 7 comprises an air cell firmness regulator 38c that includes a controller 58c. The controller 58c includes a microprocessor 60c, a cabin air pressure sensor 62c or transducer, an air cell pressure sensor 64c, and a combination occupant sensor and piezoelectric power source 68c, 74c. As with the embodiments already described, the cabin air pressure sensor 62c, air cell pressure sensor 64c and occupant sensor/power source 68c, 74c are connected to the microprocessor 60c. The cabin air pressure sensor 62c is configured to sense cabin pressure and the air cell pressure sensor 64c is configured to sense air cell pressure.

This embodiment 34c includes only a single 2-way air valve shown at 100 in Figure 7. The single 2-way air valve 100 is disposed in the bladder wall 48c of the air cell module bladder 36c. The valve 100 is positioned to allow fluid communication between the air cell module bladder

36c and the cabin atmosphere. According to this embodiment, the microprocessor 60c is programmed to control air cell firmness by modulating and controlling the direction of airflow through the single 2-way valve in accordance with feedback signals received from the pressure sensors 62c, 64c, 74c.

The open cell memory foam 92c disposed in the interior cavity 46c of the air cell bladder 36c supports an array of piezoelectric elements 70c included in the combination seat occupant sensor 74c and electrical power source 68c. The array of piezoelectric elements 70c is supported in the foam 92 in a three-dimensional pattern optimized to provide maximum electrical power to the microprocessor 60c and the 2-way valve 100 and maximum sensitivity to the presence of a seat occupant. In addition to providing a control signal, the piezoelectric elements 70c, upon deflection, generate electrical power for the microprocessor 60c and valve when seat occupant movement bends one or more of the piezoelectric elements 70c. As shown in Fig. 7, the piezoelectric elements 70c are strategically placed at locations within the foam 92 where the most pressure and movement is likely to occur.

An alternative arrangement for the piezoelectric elements 70c of the air cell module embodiment 34c of Figure 7 is shown in Figure 8. In this alternative arrangement, there are six such piezoelectric elements 70c, each having an elongated flat rectangular shape, a longitudinal axis 102 and a lateral axis 104 perpendicular to the longitudinal axis 102. The six elements

70c include a first group of three elements shown at 104 in Figure 8. This first group of three elements 104 is arranged such that each of the tliree elements in the group are oriented with their respective longitudinal axes aligned parallel to respective mutually peφendicular x, y and z coordinate axes 106.

The alternative arrangement of Figure 8 also includes a second group of tliree piezoelectric elements shown at 108. This second group of three elements is arranged such that each of the three elements in the group are oriented with their respective longitudinal axes aligned parallel to the respective longitudinal axes of the first group of elements 104. The respective lateral axes of the second group of tliree piezoelectric elements are aligned peφendicular to the respective lateral axes of the first group of elements. This combined arrangement of the two groups 104, 108 yields better accuracy and optimizes feedback from the piezoelectric elements 70c by positioning the elements 70c to intercept movement and forces applied in any direction through the open-celled memory foam 90c. This arrangement also helps to reduce or eliminate false indications of seat occupant presence. Such false indications are reduced by programming the microprocessor 60c to require simultaneous signals from two or more elements 70c of the sensor array 74c before registering the presence of an occupant.

According to the alternative air cell module embodiment 34c of Figure 7, the open-celled memory foam 92c disposed in the interior cavity 46c of the air cell bladder 36c takes the place of the mechanical pumps 50, 50a, 50b of the air cell module embodiments of Figures 1-3, 5 and 6. The foam-filled interior cavity 46c of the air cell module bladder 36c serves to increase air cell pressure in much the same way as the mechanical bellows pumps 50, 50a, 50b described above. To increase air cell pressure the microprocessor 60c signals the 2-way air valve 100 to open in the inward direction whenever the piezoelectric elements 70c of the occupant sensor 74c sense that there has been a general release of occupant pressure on the air cell module bladder 36c. This allows foam expansion to draw air from the cabin atmosphere into the interior cavity 46c of the air cell module bladder 36c and through the open cell structure of the foam 92c. When the piezoelectric elements 70c sense a general increase in occupant seat pressure, the microprocessor 60c signals the 2-way valve 100 to close. This prevents air from escaping the interior cavity 46c of the air cell module bladder 36c. Pressure relief is provided through relief valve 56c as in previously described embodiments.

The occupant support assembly 20 may additionally comprise an air cell zone as is generally indicated at 110 in Figure 9. In Figure 9, the air cell zone 110 is shown as including five interconnected air cell modules 34d. However, other embodiments may include any number of interconnected air cell modules.

The air cell modules 34d are in fluid communication with each other through a zone manifold, generally indicated at 112 in Figure 9. The modules 34d are in fluid communication to equalize the air pressure between the respective air cell modules 34d to a single air cell zone pressure value.

An air cell firmness regulator, generally indicated at 38d, is additionally connected to each air cell module 34d via manifold 112 and interconnecting flow passages 132, representatively shown as air tubes. The air cell firmness regulator 38d includes a single shared controller comprising a microprocessor 60d, an air cell zone pressure sensor 64d and a cabin pressure sensor 62d.

The air cell zone pressure sensor 64d is mounted on the zone manifold 112 in a position to sense the air cell zone pressure. The cabin pressure sensor 62d is also mounted on the zone manifold 112 but may be supported in any position where it can sense cabin air pressure.

The air cell firmness regulator 38d also includes a pressure relief valve 56d mounted in an air cell zone wall 114, an inner surface of which defines the air cell zone interior region 116. In the embodiment of Figure 9, the pressure relief valve 56d is mounted in a portion of the air cell zone wall 114 that is also a wall of the zone manifold 118. However, in other embodiments, the pressure relief valve 56d may be supported in any part of the air cell zone wall 114 where it can provide fluid communication between an air cell zone interior region 116 and the cabin atmosphere.

The microprocessor 60d may be mounted on the zone manifold 112 as shown in Figure 9, and is connected to the pressure sensors 62d, 64d and the pressure relief valve 56d. The microprocessor 60d is programmed to modulate the relief valve 56d between an open position and a closed position.

The open position of the relief valve 56d allows fluid communication between the air cell zone interior region 116 and the cabin atmosphere. The closed position of the relief valve 56d prevents such fluid communication. The microprocessor 60d is programmed to maintain a desired air cell firmness value in the air cell modules 34d of the air cell zone 110 by modulating the pressure relief valve 56d in response to signals from the pressure sensors 62d, 64d.

The occupant support assembly may additionally comprise more than one air cell zone connected by a common manifold 120 as shown at 20f in Figure 10. The embodiment of Figure 10 shows three air cell zones

1 lOe, all three of which share a single microprocessor 60e and a single pair of pressure sensors 62e, 64e. However, each of the three air cell zones HOe includes its own pressure relief valve 56e mounted on a respective zone manifold 112e. Three air tubes 122 connect the respective zone manifolds 112e to the common manifold 120 and provide fluid communication between the air cell zones HOe through the common manifold 120. The common manifold 120 has an interior manifold cavity 124 connected to an interior region 116e of each zone 1 lOe through one of three manifold openings 126. The manifold interior cavity 124 is in fluid communication with each of the three zone interior regions 116e through one of the three manifold openings 126.

A single cabin pressure sensor 62e provides the necessary cabin pressure information to the microprocessor 60e. The cabin pressure sensor 62e may be mounted on the common manifold 120 as shown in Figure 10. A single air pressure sensor 64e is mounted on the common manifold 120 in a position to detect air pressure within the interior cavity

124 of the common manifold 120. The air pressure sensor 64e on the common manifold 120 is connected to the microprocessor 60 to enable the sensor 64e to transmit common manifold pressure information to the microprocessor 60e. A solenoid-actuated valve 128 is mounted in each the three manifold openings 126. All three valves 128 are connected to the microprocessor 60e. The microprocessor 60e is programmed to signal the valves 128 to open in a predetermined sequence to repeatedly sample the air pressure in each of the three air cell zones 1 lOe. In this way, the single pressure transducer 64e is able to feed the necessary air cell zone pressure information for each air cell zone HOe back to the microprocessor 60e. The microprocessor 60e maintains desired air cell firmness values in each respective air cell zone HOe by modulating the respective pressure relief valves 56e for each air cell zone HOe in response to pressure feedback information from the manifold air pressure sensor 64e and the cabin air pressure sensor 62e.

As shown in Figure 11, the occupant support assembly 20f may include an array 44f of air cell modules 34f that share a microprocessor 60f and pressure sensors 62f, 64f, but that include separate pressure relief valves 56f. In the embodiment of Figure 11, five such air cell modules 34f are shown. However, other embodiments may include more or less modules 34f as required for a particular application. A pressure relief valve 56f is mounted in the bladder 36f of each of the five air cell modules 34f in a position to allow fluid communication between each bladder 36f and the cabin atmosphere. A common manifold 112f has an interior cavity 124f connected to each of the five air cell modules 34f through respective manifold openings 126f and an air tubes

132f. The manifold interior cavity 124f is in fluid communication with each of the five air cell bladders 36f through the respective manifold openings and air tubes 132f.

A cabin pressure sensor 62f is connected to the microprocessor 60f and is mounted on the common manifold 112f. However, the cabin pressure sensor 62f may be mounted in any position where it can provide cabin pressure information to the microprocessor 60f. An air pressure sensor 64f mounted on the common manifold 112f in a position to detect air pressure within the common manifold 112f. The air pressure sensor 64f is connected by electrical wire to the microprocessor 60f to enable the sensor to transmit common manifold pressure information to the microprocessor 60f.

A solenoid-actuated manifold valve 128f is mounted in each of the five manifold openings 126f and is connected to the microprocessor 60f. The microprocessor 60f is programmed to signal the five manifold valves 128f to open in a predetermined sequence to repeatedly sample the air pressure within each of the five air cell bladders 36f. The microprocessor 60f achieves and maintains desired air cell firmness values in each of the five bladders 36f by modulating the pressure relief valve 56f for each air cell module in response to pressure feedback information from the manifold air pressure sensor 64f and the cabin air pressure sensor 62f.

The occupant support assembly embodiments 20e, 20f of Figures 10 and 11 may include controllers having non-volatile memory devices as shown at 130 and 13 Of in Figures 10 and 11 respectively. In each embodiment the device 130, 130f is connected to the microprocessor 60e,

60f. A predetermined comfort standard is stored in the memory device 130, 130f and is accessible to the microprocessor 60e, 60f. This comfort standard data can be compiled and coded for use with any number of individual air cell modules 34f as shown in Figure 11 or, as shown in Figure 10, with any number of multi-cell air cell zones 1 lOe. The comfort standard may, for example, be in the form an algorithm such as the one described in U.S. Patent No. 5,283,735 (incoφorated herein by reference).

In embodiments including multiple-module air cell zones 11 Oe, the comfort standard includes desired air cell firmness values to be maintained in all the interconnected air cell bladders 36e of each respective air cell zone

HOe. The microprocessor 60e is programmed to maintain the desired firmness values in the air cell bladders 36e of each respective zone HOe. It does this by comparing the actual air cell firmness value of each respective zone HOe to the desired firmness values. It then modulates the pressure relief valve 56e of each respective zone HOe to eliminate any differential between the actual and desired firmness values.

In embodiments including individual air cell modules 34f, the comfort standard includes desired air cell firmness values to be maintained in each respective air cell bladder 36f. The microprocessor 60f is programmed to maintain the desired firmness values in each respective air cell bladder 36f.

It does this by comparing the actual air cell firmness value of each respective bladder 36f to the desired firmness values. It then modulates the pressure relief valve 56f of each respective module 34f to eliminate any differential between the actual and desired firmness values. The description and drawings illustratively set forth my presently preferred invention embodiments. I intend the description and drawings to describe these embodiments and not to limit the scope of the invention. Obviously, it is possible to modify these embodiments while remaining within the scope of the following claims. Therefore, within the scope of the claims, one may practice the invention otherwise than as the description and drawings specifically show and describe.

Claims

I claim:

1. In an occupant support assembly (20, 20d, 20e, 20f) for mounting within a cabin of a vehicle, the cabin including a cabin atmosphere having a cabin air pressure value; the assembly comprising: a seat surface (32) configured to receive and support at least a portion of the body of a human occupant; a first air cell module (34, 34a, 34b, 34c, 34d, 34e, 34 supported adjacent the seat surface (32), the first air cell module including an inflatable bladder (36, 36a, 36b, 36c, 36d, 36e, 36f) having a variable air cell firmness value that increases as the ratio of air cell pressure to cabin pressure increases, the first air cell module including an air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e, 38f) configured to control air cell pressure; the improvement comprising: the air cell firmness regulator configured to use cabin pressure changes in providing desired air cell firmness, the cabin pressure decreasing with increasing aircraft altitude.

2. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 in which the air cell firmness regulator (38, 38a, 38b, 38c,

38d, 38e, 38f) is configured to increase air cell firmness by allowing cabin pressure to decrease.

3. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 2 in which the air cell firmness regulator (38, 38a, 38b, 38c,

38d, 38e, 38f) is configured to cooperate with an aircraft pressurization system that allows cabin pressure to decrease according to a predetermined pressurization schedule as the pressure altitude of the aircraft increases.

4. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 in which the air cell firmness regulator (38, 38a, 38b, 38c, 38d, 38e, 38f) includes a controller comprising: a microprocessor (60, 60a, 60b, 60c, 60d, 60e, 60f); a cabin air pressure sensor (62, 62a, 62b, 62c, 62d, 62e, 62f) connected to the microprocessor and configured to sense cabin pressure; an air cell pressure sensor (64, 64a, 64b, 64c, 64d, 64e, 64f) connected to the microprocessor and configured to sense air cell pressure; the microprocessor being programmed to control air cell firmness in accordance with feedback inputs received from the pressure sensors.

5. An occupant support assembly (20, 20f) as defined in claim 4 in which the air cell firmness regulator (38, 38a, 38b, 38c, 38f) includes a pressure relief valve (56, 56a, 56b, 56c, 56f) supported in a position to allow fluid communication between an interior chamber (46, 46a, 46b, 46c, 46f) of the first air cell module bladder (36, 36a, 36b, 36c, 36f) and the cabin atmosphere, the microprocessor (60, 60a, 60b, 60c, 60f) being connected to the relief valve, the relief valve being configured to open and close in response to control signals from the microprocessor.

6. An occupant support assembly (20, 20f) as defined in claim 5 in which the controller is configured to: increase air cell firmness by closing the relief valve (56, 56a, 56b,

56c, 56f) as cabin pressure decreases; and to decrease air cell firmness by opening the relief valve when cabin pressure is less than air cell pressure.

7. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 in which the air cell firmness regulator (38, 38a, 38b, 38d, 38e, 38f) includes a manual pump (50, 50a, 50b, 50d, 50e, 50f), the manual pump being configured to increase air pressure within the first air cell module bladder (36, 36a, 36b, 36d, 36e, 36f) in response to seat occupant movement.

8. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 7 in which the manual pump (50, 50a, 50b, 50d, 50e, 50f) is a mechanical bellows pump.

9. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 includes at least one additional air cell module (34, 34d,

34e, 34f), the air cell modules being disposed in an air cell array (44, 44d, 44e, 44 f), the air cell array configured to enhance seat occupant comfort.

10. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 further including a seat cushion (26) comprising a foam bun (40), the first air cell module (34, 34a, 34b, 34c, 34d, 34e, 34f) being embedded within the foam bun of the seat cushion.

11. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 1 further including a seat back (24) comprising a foam bun

(42), the first air cell module (34, 34a, 34b, 34c, 34d, 34e, 34f) being embedded within the foam bun of the seat back.

12. An occupant support assembly (20) as defined in claim 5 in which the air cell firmness regulator (38, 38a, 38b, 38c) includes a piezoelectric element (70, 70a, 70b, 70c) connected to the microprocessor (60, 60a, 60b, 60c) to provide electrical power to at least one of the microprocessor and the relief valve (56, 56a, 56b, 56c).

13. An occupant support assembly (20) as defined in claim 12 in which the piezoelectric element (70, 70a, 70b, 70c) is mounted on a bladder wall (48, 48a, 48b, 48c) of the first air cell module bladder (36, 36a, 36b, 36c).

14. An occupant support assembly (20) as defined in claim 4 further including an electrical current path (86, 86a, 86b, 86c) extending from the microprocessor (60, 60a, 60b, 60c), the electrical current path being integrated into the bladder wall (48, 48a, 48b, 48c) of the first air cell module (34, 34a, 34b, 34c).

15. An occupant support assembly (20) as defined in claim 12 in which the air cell firmness regulator (38, 38a, 38b, 38c) includes a battery

(72, 72a, 72b, 72c) connected to the controller microprocessor (60, 60a, 60b, 60c) and the piezoelectric element (70, 70a, 70b, 70c) and configured to store electrical power received from the piezoelectric element and to provide electric power to at least one of the microprocessor and the relief valve (56, 56a, 56b, 56c).

16. An occupant support assembly (20) as defined in claim 15 in which the battery (72, 72a, 72b, 72c) is mounted on the bladder wall (48, 48a, 48b, 48c) of the first air cell module bladder (36, 36a, 36b, 36c).

17. An occupant support assembly (20) as defined in claim 12 further including a seat occupant sensor (74, 74a, 74b, 74c) and a landing sensor (76, 76a, 76b, 76c) each connected to the microprocessor (60, 60a, 60b, 60c), the occupant sensor configured to emit an electrical signal in response to the presence of an occupant in the occupant support assembly

(20, 20d, 20e, 20f), the landing sensor configured to sense when an aircraft containing the cabin is positioned on the ground, the microprocessor being programmed to prevent the pressure relief valve (56, 56a, 56b, 56c) from opening when signals from the seat occupant sensor and landing sensor indicate that the seat is occupied and the aircraft is on the ground.

18. An occupant support assembly (20) as defined in claim 17 in which the piezoelectric element (70, 70a, 70b, 70c) is configured to sense the presence of a seat occupant.

19. An occupant support assembly (20, 20f) as defined in claim 5 in which the microprocessor (60, 60a, 60b, 60c, 60f) is programmed to maintain air cell pressure by signaling the pressure relief valve (56, 56a, 56b, 56c, 56f) to open and close in response to inputs from the air cell pressure sensor (64, 64a, 64b, 64c, 64f).

20. An occupant support assembly (20, 20d, 20e, 20f) as defined in claim 4 in which at least one of the air pressure sensors (62, 62a, 62b, 62c, 62d, 62e; 64, 64a, 64b, 64c, 64d, 64e) includes a piezoelectric element (66).

21. An occupant support assembly (20) as defined in claim 4 in which the air cell firmness regulator (38b) includes a first 2-way air valve (94) disposed in the bladder wall (48b) of the first air cell module bladder (36b) in a position to allow fluid communication between the interior chamber (46b) of the first air cell module bladder and a pump interior chamber (54b), and a second 2-way air valve (96) disposed in a pump exterior wall (98) in a position to allow fluid communication between the pump interior chamber and the cabin atmosphere, the microprocessor (60b) being programmed to control air cell firmness by opening and closing and controlling direction of airflow through the first and second 2-way valves in response to inputs from the pressure sensors (62, 64, 74).

22. An occupant support assembly (20) as defined in claim 1 in which open-celled foam (90, 90c) is disposed within the interior chamber (46a, 46c) of the first air cell module bladder (36a, 36c).

23. An occupant support assembly (20) as defined in claim 1 in which open-celled foam (90c) is disposed within the interior chamber (46c) of the first air cell module bladder (36c) and in which the assembly includes: a controller including a microprocessor (60c), a cabin air pressure sensor (62c) connected to the microprocessor and configured to sense cabin pressure, and an air cell pressure sensor (64c) connected to the microprocessor and configured to sense air cell pressure; a 2-way valve (100) disposed in a bladder wall (48c) of the first air cell module (34c) in a position to allow fluid communication between the first air cell module and the cabin atmosphere; and a piezoelectric element (70, 70a, 70b, 70c) supported in the foam

(90c) and configured to provide electrical power to the microprocessor (60, 60a, 60b, 60c, 60d, 60e) and the 2-way valve, the electrical power being generated by distortion of the piezoelectric element resulting from seat occupant movement, the microprocessor being programmed to control air cell firmness by modulating and controlling direction of air flow through the 2- way valve in accordance with feedback signals received from the pressure sensors.

24. An occupant support assembly (20) as defined in claim 23 further including an array (104, 108) of piezoelectric elements (70c) supported in the foam (90c) and connected to the microprocessor (60c).

25. An occupant support assembly (20) as defined in claim 23 in which the piezoelectric element (70c) is configured to sense the presence of a seat occupant and to signal the microprocessor (60c) that an occupant is present.

26. An occupant support assembly (20) as defined in claim 24 in which the piezoelectric elements (70c) each include an elongated metallic strip having a longitudinal axis (102) and in which the piezoelectric element array (104, 108) includes a first group (104) of three such elements configured such that the metallic strips are oriented with their respective longitudinal axes aligned parallel to respective mutually pe╧åendicular x, y and z coordinate axes (106).

27. An occupant support assembly (20) as defined in claim 26 in which each elongated metallic strip has a lateral axis (104) pe╧åendicular to its respective longitudinal axis (102) and in which the piezoelectric element array (104, 108) includes a second group (108) of three such piezoelectric elements (70c) configured such that their respective metallic strips are oriented with their respective longitudinal axes aligned parallel to the respective longitudinal axes of the first group (104) of elements and their respective lateral axes aligned pe╧åendicular to the respective lateral axes of the first group of elements.

28. An occupant support assembly (20) as defined in claim 24 in which the piezoelectric elements (70c) are strategically placed at locations within the foam (90c) where the most pressure and movement is likely to occur.

29. An occupant support assembly (20d, 20e) as defined in claim 1 in which: the assembly additionally comprises an air cell zone (110) including the first air cell module (34d, 34e) and a second air cell module (34d, 34e), the second air cell module having a variable air cell pressure value and a variable air cell firmness value that increases as the ratio of air cell pressure to cabin pressure increases, the second air cell module having a bladder (36d, 36e) in fluid communication with the bladder (36d, 36e) of the first air cell module to equalize the respective air cell pressure values to a single air cell zone pressure value; the air cell firmness regulator (38d, 38e) of the first air cell module is connected to and is shared by the second air cell module; the air cell firmness regulator includes an air cell zone pressure sensor (64d) supported in a position to sense the air cell zone pressure; the air cell firmness regulator includes a cabin pressure sensor (62d) supported in a position to sense cabin pressure the air cell firmness regulator includes a pressure relief valve (56d) supported in an air cell zone wall (114) in a position to provide fluid communication between an air cell zone interior region (116) and the cabin atmosphere; the air cell firmness regulator includes a controller (38d) connected to the pressure sensors (62d, 64d) and the pressure relief valve (56d), the controller being configurable to modulate the relief valve between an open position allowing fluid communication between the air cell zone interior region and the cabin atmosphere and a closed position preventing such fluid communication; and the controller is configurable to maintain a desired air cell firmness value by modulating the pressure relief valve in response to signals from the pressure sensors.

30. An occupant support assembly (20d, 20e) as defined in claim 29 further including a zone manifold (112) interconnecting the first and second air cell modules (34d, 34e), the air cell zone pressure sensor (64d, 64e) being supported on the zone manifold.

31. An occupant support assembly (20e) as defined in claim 1 the assembly further including: at least two air cell zones (1 lOe), each zone including at least two air cell modules (34e), each module having an air cell bladder (36e), the bladders of each zone being interconnected to define a single zone interior region (116e) for each zone, the bladders within each zone being in fluid communication with each other to equalize the respective air cell pressure values to a single air cell zone pressure value for each zone interior region; the zones sharing a microprocessor (60e) and each zone having a pressure relief valve (56e) mounted in a position to allow fluid communication between each zone interior region and the cabin atmosphere; a common manifold (120) having an interior cavity (124) connected to each zone through a respective manifold opening (126), the manifold interior cavity being in fluid communication with each of the zone interior regions through the respective manifold openings; a cabin pressure sensor (62e) connected to the microprocessor (60e) and disposed in a position to provide cabin pressure information to the microprocessor; an air pressure sensor (64e) disposed in a position to detect air pressure within the common manifold, the air pressure sensor being connected to the microprocessor (60e) to enable the sensor to transmit common manifold pressure information to the microprocessor; and a solenoid-actuated manifold valve (128) mounted in each of the manifold openings and connected to the microprocessor, the microprocessor being programmed to signal the manifold valves to open in a predetermined sequence to repeatedly sample the air pressure within each zone interior region, the microprocessor (60e) maintaining desired air cell firmness values in each zone by modulating the pressure relief valve (56e) for each zone in response to pressure feedback information from the manifold air pressure sensor (64e) and the cabin air pressure sensor (62e).

32. An occupant support assembly (20e) as defined in claim 31 in which the controller includes: a memory device (130) connected to the microprocessor (60e); and a predetermined comfort standard stored in the memory device, the comfort standard including desired air cell firmness values to be maintained in the air cell bladders (36e) of each respective air cell zone (HOe), the microprocessor being programmed to maintain the desired firmness values in the air cell bladders of each respective zone by comparing the actual air cell firmness value of each respective zone to the desired firmness values and modulating the pressure relief valve (56e) of each respective zone to eliminate any differential between the actual and desired firmness values.

33. An occupant support assembly (20f) as defined in claim 1 the assembly further including: at least two air cell modules (34f), each module having an air cell bladder (36f), the modules sharing a microprocessor (60f) and each module having a pressure relief valve (56f) mounted in a position to allow fluid communication between each bladder and the cabin atmosphere; a common manifold (112f) having an interior cavity (124f) connected to each module through a respective manifold opening (126f), the manifold interior cavity being in fluid communication with each of the air cell bladders through the respective manifold openings; a cabin pressure sensor (62f) connected to the microprocessor (60f) and disposed in a position to provide cabin pressure information to the microprocessor; an air pressure sensor (64f) disposed in a position to detect air pressure within the common manifold, the air pressure sensor being connected to the microprocessor (60f) to enable the sensor to transmit common manifold pressure information to the microprocessor; and a solenoid-actuated manifold valve (128f) mounted in each of the manifold openings and connected to the microprocessor, the microprocessor being programmed to signal the manifold valves to open in a predetermined sequence to repeatedly sample the air pressure within each air cell bladder, the microprocessor (60f) maintaining desired air cell firmness values in each bladder by modulating the pressure relief valve (56f) for each air cell module in response to pressure feedback information from the manifold air pressure sensor (64f) and the cabin air pressure sensor (62f).

34. An occupant support assembly (20, 20f) as defined in claim 33 in which the controller includes: a memory device (130f) connected to the microprocessor (60f); and a predetermined comfort standard stored in the memory device, the comfort standard including desired air cell firmness values to be maintained in each respective air cell bladder (36f), the microprocessor being programmed to maintain the desired firmness values in each respective air cell bladder by comparing the actual air cell firmness value of each respective bladder to the desired firmness values and modulating the pressure relief valve (56f) of each respective module to eliminate any differential between the actual and desired firmness values.