WO2018130824A1

WO2018130824A1 - Cushion

Info

Publication number: WO2018130824A1
Application number: PCT/GB2018/050057
Authority: WO
Inventors: Gavin James; Stuart Moore
Original assignee: The Helping Hand Company (Ledbury) Limited
Priority date: 2017-01-10
Filing date: 2018-01-10
Publication date: 2018-07-19
Also published as: GB2558614A; GB201700401D0

Abstract

A cushion (10) for supporting a seated or reclining person has a pressure detecting means for detecting a pressure exerted by the person on the cushion, and an announcement means (38), the announcement means including and being adapted to issue a pre-recorded verbal warning including an instruction for the person when the pressure applied to the cushion (10) exceeds a pre-determined pressure threshold continuously over a pre-determined period of time.

Description

CUSHION

The present invention relates to a cushion for monitoring persons who are at risk of developing pressure ulcers.

BACKGROUND TO THE INVENTION

Patients who spend long periods of time in one position, whether in hospital or otherwise, are at risk of pressure ulcers forming. Whilst the skin can tolerate a high pressure for short period, or sustained lower pressure over a longer period, spending excessive time in one position can cause capillaries in the skin to close up, which may lead to skin necrosis and the subsequent formation of a pressure ulcer (also known as pressure sores or bedsores). Patients at risk of developing such ulcers include, for example, those who are elderly, paraplegic, tetraplegic, critically ill or terminally ill. The most commonly affected parts of the body can include the sacrum, the coccyx, the heels and the hips, although they may also form elsewhere.

Pressure ulcers can arise due to sustained pressure on an area of soft tissue, often over a bony prominence, with a range of factors potentially contributing to their formation, including but not limited to: shearing (where the skin remains static but the underlying tissues do not) and microclimate (temperature and level of moisture) between the bed and a patient's skin. Perspiration and incontinence both contribute to the skin microclimate, increasing the level of moisture and potentially accentuating the development of one or more pressure ulcers. The early identification of pressure ulcers can greatly increase the chance of successful treatment, and although the technique of regularly turning bedridden patients has long been known to help reduce their prevalence, this requires nursing staff, for example, to adhere to a regular schedule of turning multiple patients. Such a regime also reduces patient autonomy, which may have detrimental effect on the self-esteem of patients and hasten the onset of dementia. Maintaining a healthy diet can also minimise the degree to which pressure sores affect patients, as can effective management of the skin microclimate.

Currently, some systems use pressure sensors to detect whether a person is sat on a seat or in bed, for example, which can further be used to identify if they have left the seat or bed, or possibly fallen off. Other systems monitor the specific pressure under a person on a seat or bed.

It is an objective of the present invention to provide an improved means for reducing or substantially obviating the aforementioned problems.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a cushion for supporting a seated or reclining person, comprising at least one pressure detecting means for detecting a pressure exerted by the person on the cushion, and an announcement means, the announcement means including and being adapted to issue a pre-recorded verbal warning when the pressure applied to the cushion exceeds a pre-determined pressure threshold continuously over a predetermined period of time, and the pre-recorded verbal warning including an instruction to move position.

The cushion replaces or may be used in addition to cushions or mattresses presently in use. The pressure detecting means allows the pressure exerted by the person on the cushion to be monitored so that excessive pressures or excessive durations of pressure exposure can be detected. The announcement means allows an instruction to be issued when such a situation is detected. A verbal (or worded) instruction is issued so that information can be communicated to the user in a familiar and comprehensible way, conveying more information than, for example, a simple tone. This may cause the user to adjust his position or rise from the cushion before a pressure sore can form without the intervention of a nurse or carer. Advantageously, the burden of labour on the nurse or carer is thus reduced, and the user is given greater autonomy. The verbal instruction could, for example, request the user to change position or to leave the cushion and stand, or it could inform the user that an unacceptable level of pressure is being exerted, or that a moderate or acceptable level of pressure has been exerted for too long.

The cushion may include a controller adapted to control the announcement means, the controller being programmed to reset a period of time that has elapsed since a pressure threshold was exceeded if the pressure drops below the pressure threshold for an interval. Advantageously, if the user shifts position momentarily for long enough to allow blood flow to be restored in the capillaries in the pressurised area, the timer may thus be reset to prevent an unnecessary alert from being issued.

The interval may be substantially 0.5 seconds or longer. This is approximately the time required for sufficient blood flow to be restored to avoid the risk of pressure sore formation

The announcement means may be adapted to be disabled or suppressed at predetermined times. This allows a patient to sleep through the night uninterrupted if the need for rest is considered more important than the need to minimise the risk of pressure sores.

The verbal instruction may be in any language. Means for changing the language may be provided so that the same cushion may be repurposed for use by a second user who understands a different language to the first user. Instructions of a variety of languages may be stored in a memory unit of the cushion with means being present for selecting the set of instructions to be relayed, or alternatively, a single set of instructions may be present, in which case means for replacing that single set with a set of instructions in a different language may be provided, for example an interchangeable memory unit or a computer interface such as a USB port. The verbal warning may comprise a series of instructions corresponding to particular body positions. The announcement means may cycle through the series during use. The cycle may be sequential, or partly or fully randomised. This encourages the user to progress through a number of positions which avoids prolonged seating in any one position. The cushion may be incorporated into or used with one of the following: a bed; a mattress; a seat; a chair; a wheelchair. The risk of pressure sore formation in users who spend a substantial amount of time using any of these devices may thus be mitigated.

At least one property of at least one of the pressure detecting means may be calibrated for a particular person. This allows a cushion to be provided for persons of varying weight and medical requirements without emitting unnecessary alerts or failing to issue alerts when required. The cushion may include an additional second pressure detecting means, the first pressure detecting means being activated at a first threshold pressure and the second pressure detecting means being activated at a second threshold pressure, higher than the first. It may be that a user can sustain a certain pressure for a certain period of time before he is at risk of developing a pressure sore, while he can sustain a higher pressure for a shorter period of time before the risk occurs. Alternatively, it may be that there is a threshold at which the pressure is unacceptable and the user must change position immediately. The inclusion of multiple pressure thresholds allows such a situation to be accommodated so that the risk of pressure sores is minimised without unnecessary alerts being issued.

The first and second pressure detecting means may be stacked within the cushion. This allows the pressure detecting means to simultaneously monitor the pressure exerted by a user in the same location on the cushion. The announcement means may issue a first message when the first threshold pressure is exceeded, and the announcement means may issue a different second message when the second threshold pressure is exceeded. This allows the user to be notified if an unacceptable pressure is being exerted. The announcement means may issue a verbal instruction when the second pressure threshold is exceeded for longer than a second pre-determined period of time. This allows the risk of pressure sores to be minimised without unnecessary alerts being issued.

The or each pressure detecting means may include first and second electrical conductors and a resilient electrical insulator disposed between the electrical conductors; in which case the adjacent electrical conductors may come into contact through the electrical insulator when a threshold pressure is applied to the cushion.

The resilient electrical insulator may include apertures through which adjacent electrical conductors come into contact when a threshold pressure is applied to the cushion. This provides a low cost structure capable of separating a pair of conducting sheets, but allowing them to contact one another when sufficient pressure is applied. This arrangement may be used in an inflatable cushion, in which the resilient insulator is provided by the gas, for example air. It may also be used with a conventional cushion, in which case the insulator may be provided by, for example, a slab of foam including apertures. This mechanism can be employed to economically monitor peak pressure over large areas, as the insulating and conducting materials can be produced extremely cheaply with existing technology.

The resilient electrical insulator of the second pressure detecting means may have a greater depth than the resilient electrical insulator of the first pressure detecting means.

The resilient electrical insulator of the second pressure detecting means may be more resistant to deformation than the resilient electrical insulator of the first pressure detecting means. The thicker or more deformation resistant insulator will cause the second pressure detecting means to be activated at a higher pressure threshold than the first pressure detecting means.

The first and second pressure detecting means may have a common electrical conductor between their resilient electrical insulators. This minimises material costs and complexity.

The cushion may be an inflatable cushion comprising at least one flexible sealed chamber filled with gas. Inflatable cushions present numerous advantages, including but not limited to compact storage, low weight, low manufacturing costs and high comfort. The gas may be air. Air is a readily available gas and is therefore highly convenient for use in inflatables.

The cushion may comprise multiple chambers. This provides a fail-safe in case a flexible sealed chamber sustains a puncture, as a cushion with multiple chambers will not totally deflate in such an eventuality, but will continue to provide partial support. The chambers may be connected or individual. They may be connected by valves.

The pressure detecting means may be a gas pressure measuring device for measuring at least one gas pressure within the cushion. This provides convenient indirect monitoring of the pressure applied to the cushion by the patient and is especially preferable in the case of an inflatable cushion, or a cushion which includes sealed gas filled sacs. The pre-recorded verbal warning may comprise a plurality of instructions. At least some of those instructions may correspond to the pressure in selected chambers. The announcement means is preferably adapted to select one or more of the plurality of instructions corresponding to the pressure distribution on the chambers during use. This allows the selection of instructions which indicate which part of the body is under excessive pressure, according to the location(s) of the chambers at higher pressures. It also enables the selection of instructions which indicate if the user is leaning too much in a particular direction. The announcement means may be adapted to issue a tone or verbal message for indicating that the cushion is operational, once a person has sat on the cushion. This is useful if the power source has run out, either due to prolonged use, or due to lack of use and gradual loss of power (e.g. if battery powered). The announcement means may include a mobile device capable of electronically connecting to the cushion. The mobile device may be a smartphone or a tablet, for example. The mobile device may be adapted to receive a signal from the cushion and issue the pre-recorded warning. The signal is preferably sent when the pressure applied to the cushion exceeds the pre-determined pressure threshold continuously over the pre-determined period of time. Preferably, the mobile device is the patient's phone or tablet computer. This allows the patient to be instructed to move position via their own electronic device. This can attract the patient's attention more successfully than using a speaker inside the cushion.

There may be a mobile device or computer capable of electronically connecting to the cushion. The mobile device or computer may include an interface useable to adjust the predetermined period of time. The interface may alternatively or additionally be useable to adjust: the or each pre-determined pressure threshold, and/or the pre-recorded verbal warning. The interface may be an app or computer program. This enables a therapist to adjust the cushion based on data gathered through use of the cushion by a patient, improving the quality of care provided. This can be done remotely, avoiding the need to disturb a patient to change properties of the cushion. It also allows the verbal warning to be customised, e.g. by patient name, or to set the warning in a language suitable for the patient. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made by way of example only to the accompanying drawings, in which:

Figure 1 shows an exploded perspective view of a first embodiment of a pressure monitoring cushion; Figure 2 shows a cross-sectional view of the pressure monitoring cushion of Figure 1 in use, where the uppermost pressure sensor is in operation;

Figure 3 shows a cross-sectional view of the pressure monitoring cushion of Figure 1 in use, where the upper and lower pressure sensors are both in operation; and

Figure 4 shows a cross-sectional view of a second embodiment of a pressure monitoring cushion.

DESCRIPTION OF PREFERRED EMBODIMENT(S)

Referring to Figure 1, a first embodiment of a pressure monitoring cushion is indicated generally at 10. The cushion 10 includes a top cushion 12 and a bottom cushion 14. The top and bottom cushions 12, 14 are the same thickness in this embodiment. This corresponds to a depth of 25 mm for the cushions 12, 14. The materials used to construct the cushion 10 are selected to ensure that regular washing will not cause degradation of the device or impede its functionality.

First and second pressure sensors are provided in the cushion 10. The first and second pressure sensors are disposed in different horizontal planes in the cushion 10. In this embodiment, the pressure sensors are between the cushions 12, 14. The pressure sensors are also stacked one above the other within the cushion 10. In this embodiment, the first pressure sensor lies above the second pressure sensor in the cushion 10. The pressure sensors act as pressure switches. The first pressure sensor includes two electrical conductors (or conductive sheets) 18, 20, and a resilient electrical insulator (or insulating layer) 22 disposed between the sheets 18, 20. The second pressure sensor also includes two conductive sheets 20, 24, and an insulating layer 26 disposed between the sheets 20, 24. In this embodiment, the pressure sensors share a common conductive sheet 20. However, other embodiments may have distinct conductive sheets for each pressure sensor.

Each insulating layer 22, 26 is made of resilient foam, providing a cushioning effect in addition to the other cushions 12, 14. In some embodiments, the foam is CMHR foam (Combustion Modified High Resilience foam), so its fire resistance properties are enhanced and it meets relevant Fire Safety Regulations. Each insulating layer includes a plurality of through apertures 28, 30, through which the conducting layers come into contact when sufficient pressure is applied to the cushion. Applying pressure to cushion 10 compresses the insulating layers 22, 26 and allows the conductive sheets 18, 20, 24 to contact one another through the apertures. The lower insulating layer 26 is thicker than the upper insulating layer 22 in this embodiment. In this embodiment, the layers are 10 mm and 5 mm thick respectively (the drawing is not to scale). Therefore, the lower insulating layer is more difficult to compress. The actual thicknesses can be calibrated accordingly to the weight of the intended user. Overall, this gives the second pressure sensor a higher effective pressure threshold before its conductive sheets 20, 24 can come into contact, relative to the pressure threshold of the first pressure sensor.

The apertures 28, 30 extend from one side of the respective layer 22, 26 to the other. The apertures 28, 30 are spaced evenly in a 6x6 square (partially shown) in this embodiment, but may be arranged regularly or irregularly in other embodiments, with higher or lower numbers of apertures than in the present embodiment.

The apertures 28 in the upper insulating layer 22 are co-aligned with the apertures 30 in the lower insulating layer 26. In other embodiments, the apertures in different layers may be anti-aligned, or have another alignment. The insulating layers 22, 26 are compressed when the cushion 10 is sat upon, but the apertures 28, 30 substantially retain their size, shape and relative spacing in use. The conductive sheets 18, 20, 24 cover the apertures 28, 30 on the respective sides of the insulating layers 22, 26. When pressure is applied to the cushion, the conductive sheets 18, 20, 24 deform and enter the apertures 28, 30. If the applied pressure reaches the pressure threshold, the conductive sheets 18, 20, 24 deform to the extent that they contact one another through the apertures. Each conductive sheet 18, 20, 24 is a carbon-printed (or carbon-coated) sheet of polythene. The polythene is durable and can undergo deformation into the apertures 28, 30 over many cycles without wearing out. Using carbon as a conductor is better than metal because it is lighter, it will not undergo metal fatigue during repeated compression cycles, and internal arcing across air gaps will not occur if a small gap is present between the conductive sheets 18, 20, 24.

A controller 34 is connected to the conductive sheets 18, 20, 24. Side portions of parts of the cushion 10 are cut-out to accommodate the controller 34 at the side of the cushion 10. The controller 34 includes a speaker 38 and a processor (not shown). A representation of a clock 40 is also shown. The processor is adapted to be programmed to optionally deactivate the speaker 38 at night. In other words, between the hours of 2200-0700, for example, the speaker may be set to remain silent even if it would normally otherwise sound an alert. This allows users for whom sleep is a higher priority than risk of pressure sores to be accommodated.

The processor includes programmed verbal instructions or messages which are played through the activated speaker 38. An example of such a message could be "Please change position". In this embodiment, the controller stores instructions of approximately 2 seconds in length. The instructions are self-explanatory and tell the person atop the cushion to reposition themselves, or tell the carer the same, if the person is incapacitated for example. The instructions could alternatively or additionally tell the user that he is leaning too much in a particular direction. The instructions may specify a specific new position to adopt. A set of positions may be stored in a memory unit of the cushion, and the instructions may instruct the user to cycle through these positions periodically. The memory unit of the cushion may be interchangeable. Alternatively, it may be reprogrammable by means of a computer interface, for example a USB port. The computer interface may be a wireless computer interface or any known means of computer networking, for example a Bluetooth (RTM) connection. The instructions are recorded in different languages, so that the user can set the instruction language to one they understand. The cushion may include means of selecting the language of the instructions. These means may also allow the user to select a set of instructions from a group of possible sets of instructions. The cushion may also include a volume control for varying the volume of the announcement of the instructions.

In a first embodiment, the processor is programmed to activate the speaker 38 on beginning to use the cushion. Once a person has sat on the cushion, the speaker 38 issues a tone or a verbal message to indicate that it is operational. This corresponds to the conductive sheets 18, 20 of only the first pressure sensor being brought into contact. However, if sitting on the cushion brings both sets of conductive sheets 18, 20, 24 of the first and second pressure sensors into contact, a different tone or verbal message is sounded to indicate that support is inadequate. This can mean that the cushion is worn out, or that the cushion is not robust enough to properly support the person using it, or that an unacceptable level of pressure is being applied to the cushion.

In a second embodiment, the processor is programmed to activate the speaker 38 when a preset period of time (or delay period) has elapsed, causing it to emit the verbal instructions. The pre-set period is measured from the moment at which the conductive sheets 18, 20 of at least the first pressure sensor last came into contact. 'Contact' means sustained contact between the conductive sheets 18, 20, 24, i.e. where any loss of contact lasts less than 0.5 seconds, with reference to the interval below. In this embodiment, the pre-set period can be adjusted using a variable control (not shown), taking account of the condition of the user. The period may be set prior to using the cushion to 30 minutes, 3 hours, or any length of time between these. In other embodiments the period may effectively be zero, in which case the output is activated immediately. The variable control is a rotary switch which is adjustable using a screwdriver (or similar), preventing accidental changes to the pre-set period.

The controller 34 is also adapted to reset the delay period to its initial value if the person shifts their weight before the delay period has expired, i.e. if the patient moves and eases pressure on the skin, allowing blood to flow and reach the area which was under pressure. This is identified by monitoring whether the conductive sheets 18, 20 of the uppermost pressure sensor move out of contact for an interval substantially 0.5 seconds or more in length. In other embodiments, the interval (or delay period) may be linked to the second pressure sensor. The interval may also be shorter or longer as needed in alternate embodiments.

The controller is programmed to recognise when the second pressure sensor is 'closed', i.e. the conductive sheets 20, 24 are in contact. When the second and first pressure sensors are both 'closed', the controller is programmed to reduce the time until the output (i.e. the speaker 38) activates, as measured from the last contact initiated between the conductive sheets 18, 20. The time reduction may be proportional (e.g. a 50% reduction in remaining time, or a 60% reduction in total allotted time) or absolute (e.g. a reduction of 45 minutes). Other values may be selected for shortening the period until output activation. In this embodiment, there are therefore two time thresholds: a shorter time threshold, corresponding to a higher pressure threshold and closure of both the first and second pressure sensors; and a longer time threshold, corresponding to a lower pressure threshold and closure of only the first pressure sensor.

Alternatively, the output may be activated immediately upon closing of the second pressure sensor. This corresponds to a 100% reduction in the period of time, or a lower time threshold of zero and is appropriate when the second pressure threshold is calibrated to correspond to inadequate support or unacceptable pressure.

A sensor unit (not shown) is fitted to the cushion to trigger a timing circuit when a person sits on the cushion. The lower pressure threshold is set at 100 mmHg in this embodiment. The higher pressure threshold is set at 150 mmHg in this embodiment. Applied pressure at or above 100 mmHg and below 150 mmHg triggers a normal timing circuit. Applied pressure at or above 150 mmHg triggers a high pressure timing circuit, with a reduced delay until the timer elapses. Pressure below 100 mmHg triggers a circuit corresponding to minimal pressure, and no timer is activated. It will be appreciated that different threshold pressures can be used in other embodiments, e.g. for children.

In one embodiment, data corresponding to the pressure exerted on the cushion 10 is stored. The cushion 10 includes a data storage device (not shown) that can record data for up to 4 weeks worth of use. A mobile app can be used as an interface to access the data. One version of the app is a client-friendly version, and another version of the app is a therapist-oriented version which provides detailed clinical information. Data can be sent from the client to the therapist using the relevant apps. This enables the therapist to monitor cushion usage and the performance of the cushion.

The client app can also provide a push data notification to the user's mobile phone when the pre-determined time period has elapsed, prompting the user to re-position themselves. The notification can be a verbal instruction played through a speaker on the phone, or transmitted to the speaker 38 in the cushion 10. The combination of cushion and phone omits the need for a speaker in the cushion. The phone can be connected to the cushion by a wired or wireless connection.

The mobile app is capable of retrieving data from the cushion for prescriptive purposes and to assess the performance of the cushion. The data is retrieved via a Bluetooth (RTM) connection in one embodiment. A visual or graphical representation of each instance of cushion use can be generated from the data. This can be used to prescribe a new cushion based on current or projected performance. Timer settings for the cushion can be adjusted via the app by the therapist, to optimise patient care.

A power source or energy source (not shown) for powering the controller 34 is also provided, for example a battery. The battery is mounted behind the controller 34 as viewed in Figure 2. Together, the controller 34, conductive sheets 18, 20, 24 and energy source form an electrical circuit. In this embodiment, the power source is a battery. The controller 34 is programmed to issue a warning signal via the speaker 38 in the event that the battery charge is low.

Referring now to Figures 2 and 3, the pressure sensors are shown in use. In Figure 2, a person sat on the cushion 10 has compressed the first pressure sensor and its conductive sheets 18, 20 are touching.

In Figure 3, a person sat on the cushion 10 has compressed both the first and second pressure sensors, connecting all of the conductive sheets 18, 20, 24. In use, it is envisaged that the cushion 10 will be used beneath a person in a chair or a bed, where the person may be a hospital patient, for example, who is confined to a sitting or lying down position. The cushion 10 may be independent of the chair, bed or other element of furniture, or it may be integrated into (i.e. built into) the relevant item. Where the need exists to monitor multiple areas of the body that are separated by a distance greater than the size of the cushion 10, auxiliary monitoring cushions can be utilised alongside the primary cushion 10. In general, the cushion 10 would most likely be placed beneath the head, torso (including the hips) or feet of a patient, since these general areas support the body most when lying down.

When a patient is atop the cushion 10, the pressure exerted by the patient slowly causes the uppermost conductive sheet 18 to enter one or more of the apertures 28 in the upper insulating layer 22. Once contact is made between the conductive sheets 18, 20 in the first pressure sensor, the controller 34 may begin a countdown until activation of the speaker 38. If pressure is redistributed to another area of the cushion 10 (and hence to another area of the patient's skin) by, for example, the natural movement of the patient in shifting their weight occasionally, then the delay timer will reset and start anew. This is because the shift in weight will disconnect the conductive sheets 18, 20, 24 for more than 0.5 seconds, resetting the delay period.

If the pressure is not redistributed to another area of the cushion 10 then the delay period will expire and the output device will activate. This warns the patient and/or their carer(s) that the patient has not changed position significantly over the course of the delay period and is at risk of developing a pressure ulcer, and hence attention is needed. After re-positioning, the cushion 10 continues to monitor the patient in their new position in the same manner as when monitoring their first seated position.

In another embodiment, the controller may immediately activate the speaker upon contact between the conducting sheets.

Other embodiments are envisaged within the scope of the claims. For example, the first pressure sensor may be divided into two distinct halves within the upper portion of the cushion. In other words, the first pressure sensor would be a dual zone pressure sensor. A patient could be positioned above one half of the first pressure sensor and, when the relevant time period had elapsed, could be turned to lie above the other half of the first pressure sensor, i.e. on the other side of the cushion. The controller would be able to distinguish between activation of either half of the first pressure sensor and reset the timing circuit accordingly.

Further embodiments may have the cushion integrated into a car seat or a wheelchair. The electrical conductors may be composed of electrically conductive fibres as a mesh, for example. Additional pressure sensors may be provided, with greater, lesser or intermediary thickness or firmness, for example, giving a wider range of potential pressure thresholds for monitoring a patient. The controller can include a signal generator which activates after the delay period ends, sending a wireless signal to an external device. The external device receiving the signal may be a pager, a phone or a computer, for example, alerting a carer that a patient should be turned. In a further embodiment, the signal may be sent non-wirelessly. The cushion therefore provides an inexpensive means of detecting pressure above two different thresholds, where the first threshold corresponds to acceptable pressure for a given period of time, and the second (higher) threshold corresponds to pressure which can only be tolerated for a shorter period of time or not at all. Re-positioning or shifting the body of a person on the cushion allows blood flow to be restored and the areas of the body that were under pressure can recover, reducing the risk of a pressure ulcer forming in those areas.

In Figure 4, a further embodiment is envisaged in which the cushion is an inflatable cushion 100. The insulating layers are then provided by air within the inflatable cushion 100. The inflatable cushion is internally divided into multiple chambers 110. The division may be made by a horizontal membrane 112. There may be further vertical divisions 114 for structural support. Multiple independently movable sections of the cushion may be provided. The pressure monitoring means may comprise an air pressure sensor 116 for monitoring an air pressure inside the inflatable cushion. An announcement means 118 like that in the first embodiment is provided, for example having a controller, speaker and verbal pre-recorded warning.

The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A cushion for supporting a seated or reclining person, comprising at least one pressure detecting means for detecting a pressure exerted by the person on the cushion, and an announcement means, the announcement means including and being adapted to issue a pre-recorded verbal warning when the pressure applied to the cushion exceeds a pre-determined pressure threshold continuously over a predetermined period of time, and the pre-recorded verbal warning including an instruction to move position.

2. A cushion as claimed in claim 1, including a controller adapted to control the announcement means, in which the controller is programmed to reset a period of time that has elapsed since a pressure threshold was exceeded if the pressure drops below the pressure threshold for an interval.

3. A cushion as claimed in claim 1 or claim 2, in which the interval is substantially 0.5 seconds or longer.

4. A cushion as claimed in any preceding claim, in which the announcement means is adapted to be disabled or suppressed at predetermined times.

5. A cushion as claimed in any preceding claim, in which the verbal instruction is provided in a plurality of languages and a means for selecting a language is provided.

6. A cushion as claimed in any preceding claim, in which the verbal warning comprises a series of instructions corresponding to particular body positions, and the announcement means cycles through the series during use.

7. A cushion as claimed in any preceding claim, in which the cushion is an inflatable cushion comprising at least one flexible sealed chamber filled with gas.

8. A cushion as claimed in claim 7, in which the cushion comprises multiple chambers.

9. A cushion as claimed in claim 7 or claim 8, in which the pressure detecting means is a gas pressure measuring device for measuring at least one gas pressure within the cushion.

10. A cushion as claimed in claim 8, or claim 9 when dependent on claim 8, in which the pre-recorded verbal warning comprises a plurality of instructions, at least some of which correspond to pressure in selected chambers.

11. A cushion as claimed in claim 10, in which the announcement means is adapted to select one or more of the plurality of instructions corresponding to the pressure distribution on the chambers during use.

12. A cushion as claimed in any preceding claim, in which the announcement means is adapted to issue a tone or verbal message for indicating operability once a person has sat on the cushion.

13. A cushion as claimed in any preceding claim, including a second pressure detecting means, in which the first pressure detecting means is activated at a first threshold pressure and the second pressure detecting means is activated at a second threshold pressure, higher than the first.

14. A cushion as claimed in claim 13, in which the announcement means issues a first pre-recorded verbal output when the first threshold pressure is exceeded, and the announcement means issues a different second pre-recorded verbal output when the second threshold pressure is exceeded.

15. A cushion as claimed in claims 13 or claim 14, in which the announcement means issues a verbal instruction when the second pressure threshold is exceeded for longer than a second pre-determined period of time.

16. A cushion as claimed in any of claims 13 to 15, in which the first and second pressure detecting means are stacked within the cushion.

17. A cushion as claimed in any preceding claim, in which the or each pressure detecting means includes first and second electrical conductors and a resilient electrical insulator disposed between the electrical conductors; in which the adjacent electrical conductors come into contact through the electrical insulator when a threshold pressure is applied to the cushion.

18. A cushion as claimed in claim 17, in which the resilient electrical insulator includes apertures through which adjacent electrical conductors come into contact when a threshold pressure is applied to the cushion.

19. A cushion as claimed in claim 17 when dependent upon claim 13, in which the resilient electrical insulator of the second pressure detecting means has a greater depth than the resilient electrical insulator of the first pressure detecting means.

20. A cushion as claimed in claim 17 or claim 18 when dependent upon claim 13 in which the resilient electrical insulator of the second pressure detecting means is more resistant to deformation than the resilient electrical insulator of the first pressure detecting means.

21. A cushion as claimed in any of claims 17 to 20 when dependent upon claim 13, in which the first and second pressure detecting means have a common electrical conductor between their resilient electrical insulators.

22. A cushion as claimed in any preceding claim, incorporated into or used with one of the following: a bed; a mattress; a seat; a chair; a wheelchair.

23. A cushion as claimed in any preceding claim, in which at least one property of at least one pressure detecting means is adapted to be calibrated for a particular person.

24. A cushion as claimed in any preceding claim, in which the announcement means includes a mobile phone or tablet capable of connecting to the cushion, the mobile phone or tablet being adapted to receive a signal from the cushion and issue the prerecorded warning.

25. A cushion as claimed in any of claims 1 to 23, further comprising a mobile device or computer capable of connecting to the cushion, the mobile device or computer including an interface useable to adjust: the pre-determined period of time; the prerecorded verbal warning; and/or, when dependent on claim 13, the or each pressure threshold.