EP2977038B1

EP2977038B1 - Cell for inflatable mattress and inflatable mattress comprising said cell

Info

Publication number: EP2977038B1
Application number: EP15177945.1A
Authority: EP
Inventors: Nicola Gelmetti; Fabio Martinelli
Original assignee: Service Med SpA
Current assignee: Service Med SpA
Priority date: 2014-07-24
Filing date: 2015-07-22
Publication date: 2017-09-13
Anticipated expiration: 2035-07-22
Also published as: ES2643027T3; EP2977038A1

Description

The present invention refers in general to a cell for an inflatable mattress and to an inflatable mattress comprising said cell. More particularly, this invention relates to a cell for a bedsore mattress for supporting a patient and to an inflatable bedsore mattress comprising said cell.
As is known, there exist many types of bedsore mattresses that are provided with at least two series of cells which are inflated and deflated alternately according to predetermined cycles of time in order to change over time the position of the supporting sectors for the patient lying on the mattress.
The bedsore mattresses are inflated by a compressor. The operation of said compressor is controlled by a suitable management and control system that adjusts the inflation and deflation of each of the two series of cells in the mattress. In particular, said management and control systems must guarantee the maintenance of an adequate pressure in the mattress, through pressure reducers and valves, so that the body of the patient does not undergo a too high pressure or a too low pressure.
Below, reference is made to a bedsore mattress known and to its operation.
With reference to figure 1, A denotes an inflatable mattress comprising a top sheet B and a bottom sheet D which wrap twenty cells E, only one cell being represented in the figure.
The twenty cells E are held in their position between a right collector F and a left collector G, the latter being visible in figure 2.
As visible in Figure 2, the inflatable mattress A is represented in an exploded view. The inflatable mattress A is fed through a seven-way feeding tube C which is connected to a management and control system (not visible in the Figure).
The seven-way feeding tube C communicates with the right collector F, the left collector G and a sensor mat H.
The feeding tube C is connected through channels arranged on one of its faces to suitable inflating means so that it is possible to exchange pressurized air through two first delivery outlets with the right connector F and through two second delivery outlets with the left collector G.
The right collector F includes three distinct chambers which develop in parallel with each other and are called hereinafter first right track F1, second right track F2 and third right track F2. Similarly, the left collector G comprises three distinct chambers which are called hereinafter first left track G1, second left track G2 and third left track G3.
The third right track F3 communicates through a duct with the third left track G3. The first left track G1 sends pressurized air through a first connection to a first series of cells L while the first right track F1 sends pressurized air through a second connection to a second series of cells M.
In the same way, the second left track G2 sends pressurized air through a third connection to a third series of cells N while the second right track F2 sends pressurized air through a fourth connection to a fourth series of cells O.
The first series of cells L comprises a dynamic portion, fed directly by the first connection, and a static portion communicating through a static portion with the third left track G3 of the left collector G. In the same way, the remaining series of cells comprise a dynamic portion and a static portion.
Each dynamic portion communicates through a non-return valve with the respective static portion.
The third right track F3 communicates through a duct also with a head valve P. The head valve P adjusts the delivery of air to a fifth series of cells Q.
The inflatable mattress A comprises, therefore, twenty cells (denoted in general by reference letter E in Figure 1), twelve cells being formed like the first and second series of cells L, M, five cells being formed like the third and fourth series of cells N, O, and three cells being formed like the fifth series of cells Q.
The respective communications are performed to allow the management and control system to control the pressure of air within each cell so as to ensure the correct correspondence with the respective elements of the inflatable mattress A.
Below is a description of the operation of the inflatable mattress A according to prior art with reference to Figure 2.
The feeding tube C, connected to the management and control system, comprising suitable inflating means controlling the pressure of the air introduced in each of the seven channels, exchanges pressurized air with each of the above-mentioned elements of the inflatable mattress A so as to adjust the behavior of the mattress for a patient lying on the inflatable mattress A.
For example, the body of the patient may have the trunk on the first and second series of cells L, M, the feet on the third and fourth series of cells N, O, and the head on the fifth series of cells Q.
By varying the pressure imposed in the right collector F and in the left collector G it is possible to obtain an independent behavior of the first series of cells L in comparison with the second series of cells M, for example by inflating and deflating the first series or the second series alternately so as to form support areas varied with continuity for the patient lying on. In the same way, the third series of cells N and the fourth series of cells O may be inflated and deflated alternately or as required, in other ways.
Concerning the first, second, third and fourth series of cells L, M, N, 0, only the pressure in the dynamic portions is controlled while the static portions are communicating to each other and are fed through non-return valves by the dynamic portions. The static portions communicate with the third right and left tracks F3, G3.
Moreover, the third right track F3 is joined through the relative conduit to the third left track G3 so that it is possible to obtain a uniform average pressure among the various static portions.
The inflatable mattress A is provided with series of cells dedicated to specific parts of the body of the patient. The pressures of these series of cells are controlled independently from each other according to the requirements, which allows a higher flexibility of use than the mattresses having a single pair of cells inflated alternately. For example, the area dedicated to the feet may be managed independently from the areas dedicated to the trunk and the head, for example by imposing an alternate operation on the feet cells according to a predetermined timing.
In order to detect the pressure which the user exerts on the mattress, the mattresses according to the prior art provide that output air from the mattress flows in the sensor mat placed below the mattress.
The sensor mat allows to measure the average pressure of all the cells of the mattress. However, in order to know the pressure of the various areas, it would be necessary to use a plurality of sensor mats, which would complicate considerably the construction and the operation.
In order to regulate the pressure independently for each area of the body, it is necessary to use pressure reducers so as to obtained the desired result, which complicates considerably the control and management of the bedsore mattress known.
For example, in order to regulate the pressure and/or the time for the inflation of the cells of the inflatable mattress A including also the cells dedicated to the head, three independent valves and/or three pressure regulators are required to obtain the desired result.
In fact, the cell regarding the head, as described and represented above, does not allow to obtain a contact pressure different from the contact pressure used for the inflation of the static portions of the cells.
Inflatable mattresses, particularly shaped such as the inflatable mattress described in the US patent US-A-4 521 166 A , are known. This document relates to a mattress which comprises an articulated cell which acts as a pump to inflate the main portion of the inflatable mattress. This articulated cell has a series of tubular cells joined to each other and forming a kind of cylinder which is closed by two lateral cells at both respective sides. Thus, it is possible to obtain a closed chamber, closed internally to the tubular cells and to both lateral cells. This closed chamber is separated from the external ambient and must, therefore, be filled with air and also the tubular cells and the lateral cells must be filled with air, which involves a substantial consumption of air and energy for the filling operation.
An inflatable mattress is also described in DE 87 11 449 U1 .
An aim of the invention is to provide a cell for an inflatable mattress in order to overcome the problems of the prior art.
Another aim of the invention is to provide a cell and an inflatable 5 mattress of reduced consumptions and simple operation.
Another aim of the invention is to provide a cell and an inflatable mattress which allow to obtain, in a simple easy way, different contact pressures between cell and body in specific areas of the inflatable mattress.
All the aims and advantages are achieved with an articulated cell for an inflatable mattress, comprising a static portion that is not directly fed by the inflation and deflation system, and a dynamic portion, that is directly fed by the inflation and deflation system, and shaped like a cell as disclosed below, so that the static portion is capable to support the person in case the dynamic portion is not inflated and/or fed.
The cell for an inflatable mattress adapted to be
connected to an inflation and deflation system and adapted to lift a person, comprises a main body having a first volume. The main body is connected to an inflation and deflation system.
A cavity having a second predetermined volume is formed inside said main body, so that said cell comprises a main chamber having a third volume, said first volume being the sum of the second volume and third volume.
The cavity is a through cavity and is open towards the ambient outside the cell, so that the cavity may have a pressure equal to the atmospheric pressure or to the pressure of the ambient outside the cell, so as to avoid to connect it to inflation systems.
The cavity reduces the volume of air that may be contained in the cell when the cell is inflated at a first pressure, in comparison with the volume of air that would be contained in a main body without cavity. Hence, the cell according to the invention, inflated at a first pressure, has a smaller air volume than a respective known cell that has the same height and is inflated
at the same first pressure. In this way, it is possible to obtain a lower contact pressure on the external surface of the cell according to the invention than the contact pressure obtained on the cell known.
The articulated cell is characterized by the fact that the dynamic portion and the static portion are connected to each other through a non-return valve, said non-return valve allowing the passage of air from the dynamic portion to the static portion. In this way it is necessary to inflate only the dynamic portion while the static portion always remains at the maximum pressure reached by the dynamic portion, which ensures safety and reliability. Moreover, the cavity may be formed for the entire length of the main body, so as to simplify the construction and obtain a uniform, constant behaviour for the entire length of the main body.
Advantageously, the main chamber may comprise three or more secondary chambers with lateral edges. The three or more secondary chambers are connected together at their respective lateral edges, so that the third volume is formed by three or more chambers connected to each other, and a structure is formed which is closed peripherally and in which the through cavity is formed internally.
In order to obtain a structure that extends according to a main direction, the three or more secondary chambers may extend in length and may be joined together along their longer lateral edges.
Besides, one or more of the lateral edges of the three or more secondary chambers may comprise a conduit allowing the passage of air among said three or more secondary chambers so that all the corresponding secondary chambers are at the same pressure.
Furthermore, the main chamber may comprise a portion of outer surface adapted to go in contact with the person. The portion of outer surface has a contact pressure with the person. The contact pressure decreases as the volume of the main chamber decreases.
Besides, the section of the main body may be inscribed in a circumference having a first predetermined diameter and the section of the
cavity may be circumscribed to a circumference having a second predetermined diameter and the second predetermined diameter may be smaller than the first predetermined diameter. In this way, it is possible to easily determine the ratio between the volumes on the base of the ratios between the diameters. In addition, it is possible to make a comparison with the known cells having a similar height.
Advantageously, the ratio between the first predetermined diameter and the second predetermined diameter may be proportional to the third volume and, consequently, to the contact pressure perceived by the person on the portion of external surface between said cell and said person, so as to correlate, in a clear simple way, the contact pressure perceived by the person on the base of the ratio between diameters.
All the aims and advantages are also achieved with an inflatable mattress to be connected to an inflation and deflation system and adapted to lift a person, comprising:

a first series of inflatable cells;
one or more second series of cells according to what has been described previously;
a valve connected to the first series of inflatable cells and to the one or more second series of articulated cells through a feeding tube.

The valve is connected to the inflation and deflation system at a first pressure.
The first series of inflatable cells and the one or more second series of articulated cells are disposed adjacent to each other, so that all are adapted to lift a person.
In this way, the first series of cells has a lower contact pressure than the second series of articulated cells, although they are fed by the same valve at the first pressure.
Advantageously, the one or more second series of articulated cells may have a lower contact pressure than the contact pressure of the first series of inflatable cells so that the one or more second series of articulated cells may be disposed in correspondence of areas of the body of the person which need a lower contact pressure than the areas of the body of the person which are supported by the first series of inflatable cells.
In this way, it is possible to regulate the first pressure on the highest pressure required for the areas of the body specific of the first series of inflatable cells, for instance the trunk of the person, so that the pressure of contact with the trunk of the person is the desired one, on obtaining at the same time a lower contact pressure in the areas of the body of the person which are in contact with the one or more second series of inflatable cells, both the first series of inflatable cells and the one or more second series of articulated cells being connected directly to the same inflation and deflation system, without having to control two separate feedings in an independent way.
Further features and details of the invention can be better understood from the following specification which is supplied by way of a non-limiting example, as well as from the accompanying drawings, wherein:

Fig. 1 is an axonometric view of an inflatable mattress according to prior art;
Fig. 2 is an axonometric exploded view of the inflatable mattress in Fig. 1;
Fig. 3 is a schematic view of an exemplifying portion of an inflatable mattress comprising a cell according to the invention;
Fig. 4 is a schematic view of an exemplifying portion of an inflatable mattress comprising a cell according to a variant of the invention;
Fig. 5 is an axonometric view of the exemplifying portion in Fig. 4;
Fig. 6 is a schematic view of an exemplifying portion of an inflatable mattress comprising a cell according to another variant of the invention.

With reference to the attached drawings, and in particular with reference to Fig. 3, number 10 denotes an exemplifying portion of an inflatable mattress comprising a first cell 12 and a second cell 14, both cells being connected through a connection 18 to a valve 16. The first cell 12 is made according to a construction known.
A support 20 supports the first cell 12, the second cell 14 and the valve 16. The valve 16, conveniently controlled by a control system not visible in the figure, supplies pressurized air to the first cell 12 and second cell 14 so as to fill them with air till reaching a support pressure Ps predetermined or determined according to the patient to be supported by the inflatable mattress, for example the minimum pressure to support the trunk portion.
Besides, the valve 16 allows to regulate the operation of the cells by alternating the inflation and deflation as known.
The first cell 12 is shaped like a cylinder and has a height H corresponding to its external diameter. In addition, the first cell 12 contains a first volume of air. The first cell 12 is inflated with air at the pressure Ps and has, on its external surface, a first contact pressure Pc1 exerted on an external body, not visible in the figure, which is in contact with said first cell 12 on a portion of its external surface, indicated schematically in Figure 3 with a first undulating line 22.
The second cell 14 has a hollow cylindrical shape and has a height H corresponding to its external diameter, an inner cavity 25 being thus obtained. The inner cavity 25 that forms an inner surface 24 has an internal diameter h1. Hence, the inner cavity forms a second volume.
Consequently, the air contained in the second cell 14 is received more precisely into a hollow cylinder that has a distance h between the inner surface 24 of the inner cavity and the outer surface so as to define a main chamber 27 having a third volume, the first volume being the sum of the second volume and third volume.
Also the second cell 14, inflated with air at pressure Ps, has, on its external surface, a second contact pressure Pc2 different from pressure Pc1, exerted on an analogous external body, not visible in Figure 3, which is in contact with the second cell 14 on a portion of its external surface, indicated in Figure 3 with a second undulating line 26.
The second contact pressure Pc2 is different and more precisely, lower than the first contact pressure Pc1 because the geometry of the two cells is different. The volume of the air contained is consequently different and also the behavior with the external body is different.
Said different behavior occurs under the same height H. In this way, it is possible to obtain a behavior that depends on the particular construction of the cell, determining different contact pressures.
According to a variant of the invention, as visible in Figures 4 and 5, a second exemplifying portion 100 of an inflatable mattress comprises a third cell 50 which is connected through a connection 118 to a valve 116. With reference to what has been described above, the reference numbers of elements corresponding to the elements represented in Figure 3 are increased by one hundred.
The third cell 50 is inflated at the same support pressure Ps and has, on its external surface, a third contact pressure Pc3, exerted on an external body, not visible in Figure 4, which is in contact with said third cell 50 on a portion of its external surface indicated in Figure 4 with a third undulating line 52 and with the reference number 52, and in Figure 5 with a third undulating area.
The third cell 50 comprises six chambers 54, only one chamber being denoted in the figure. These chambers are distributed along the entire length of the third cell 50 and their lateral edges are connected to each other through conduits 56 allowing air to flow between the chambers 54. Consequently, all the chambers 54 are inflated with air at the same support pressure Ps.
Also the third contact pressure Pc3 is different, and more precisely lower than the first contact pressure Pc1 because the geometry of the two cells is different. The volume of the air contained is consequently different and also the behavior with the external body is different.
Said different behavior occurs under the same height H so that it is possible to obtain a different behavior that depends on the particular construction of the cell, determining different contact pressures.
Besides, tests have demonstrated that the compliance of the cells varies according to the geometry and construction of the specific cell.
Hence, relations have been found to correlate the contact pressure with the particular shape of the cell so as to determine the different contact pressure obtained as the respective particular shape of each cell varies.
For example, under the same support pressure Ps, same height H and same weight of the external body applied, it has been found that as the air volume contained in the cell diminishes, there is a corresponding proportional reduction in the contact pressure exerted on the external body resting on the cell.
The greater the dimension of the cavity, that is h1, the greater the difference between Ps and Pc2.
It is possible to correlate the force transmitted by the cell to the external body resting thereon according to the cell section area filled with air.
By identifying a total area, proportional to the height H, and a partial area, proportional to the height h1, it is possible to define two limit cases.
The first limit case occurs when the partial area corresponds to the total area so as to obtain a null force and a null thrust.
The second limit case occurs when the partial area is null and, therefore, the force is maximum and the thrust is maximum because a cell is obtained which is analogous to the first cell 12.
Tests have demonstrated that the behavior of the contact pressure and, consequently, the behavior of the force applied on the external body, are proportional to the difference between total area and partial area.
Besides, the particular hollow structure of the second cell 14 and third cell 50 allows to obtain a particular damping effect while the known cells, analogous to the first cell 12, are more rigid and, consequently, less comfortable.
According to another variant of the invention, visible in Figure 6, a fourth cell 250 is connected through a connection 218 to a valve 216. Also a cell 212 is connected to the valve 216.
With reference to what has been described above, the reference numbers of elements corresponding to the elements represented in Figure 3, are increased by two hundred. The cell 212 comprises a dynamic portion 211, reached by the connection 218, as well as a static portion 213 which communicates through a non-return valve 215 with the dynamic portion 211. The non-return valve 215 allows to keep the static portion 213 at the maximum pressure reached by the dynamic portion 211. In this way, a greater safety is ensured. In fact, in the case the valve 216 does not supply pressurized air, the static portion 213 remains inflated at the pressure Ps so as to guarantee a support for the body resting on the cell 200.
The fourth cell 250 comprises a dynamic portion 260, reached by the connection 218, as well as a static portion 262 which communicates with the dynamic portion 260 through a non-return valve 264 which is analogous to the non-return valve 215, so that the static portion 262 may be maintained at the maximum pressure reached by the dynamic portion 260.
The dynamic portion 260 is inflated at the same support pressure Ps and has on its external surface, a fourth contact pressure Pc4, exerted on an external body, not visible in Figure 6, which is in contact with said fourth cell 250 on a portion of external surface indicated in 252 with a fourth undulating line.
The dynamic portion 260 comprises five chambers 254, only one chamber being denoted in Figure 6. These chambers are distributed along the entire length of the fourth cell 250.
The lateral edges of the five chambers 254 are connected to each other through conduits 256 which allow air to flow between the chambers 254. Consequently, all the chambers 254 are inflated with air at the support pressure Ps.
Also the fourth contact pressure Pc4 is lower than the contact pressure on the external surface of the cell 212 because the geometry of the two respective cells is different. The volume of the air contained is different and consequently, also the behavior with the external body is different.
Also in this variant of the invention, a different behavior occurs under the same height H. This different behavior depends on the particular construction of the cell, which results in different contact pressures.
Hence, relations have been found to correlate the contact pressure with the particular shape of the cell so as to determine the different contact pressure obtained as the respective shape of each cell varies.
Under the same support pressure Ps, same height H and same external weight applied, relations have been obtained to evaluate the contact pressure that is exerted on the external body resting on the cell as it particular construction varies.
An inflatable mattress comprising a combination of cells with at least two types of the above-mentioned cells can, therefore, be fed by a much simpler control and management system than the inflatable mattresses known since the different contact pressure perceived by the patient is obtained through the particular construction of the respective cell and not through complex combinations of valves and/or pressure reducers as it happens in the prior art.
In fact, an inflatable mattress according to the invention, fed by an only valve, maintains a different treatment for each region of the body of a patient resting on said inflatable mattress through the distribution of cells different from each other according to the desired behavior.
The cell and the relative inflatable mattress according to the invention allow, therefore, to set a predetermined pressure ratio so that in an only cycle imparted for example by a rotating valve, it is possible to obtain areas having a different contact pressure for each region of the body by simply modifying the construction of the cell.
Indeed, the particular construction of each cell according to the invention allows to use the same feed pressure for all the cells that form the inflatable mattress because each cell according to its form of construction will obtain a different contact pressure so as to apply a different pressure in different regions of the patient's body.
The known art is affected by the psychological inertia of realizing cells which are substantially equal to each other to assembly an inflatable mattress controlling subsequently the specific parameters of each region of the patient's body through valves and/or pressure regulators dedicated.
Thus, it is possible through this invention to use a management and control system which comprises an only compressor and an only valve supplying air at a certain pressure in order to obtain a different contact pressure for each region of the patient's body without needing multiple pressure regulators and much more.
Accordingly, it is possible to maintain the flexibility and effectiveness of a mattress known on simplifying at the same time the construction and reducing the number of components or avoiding the presence of elements that could be worn out or damaged.
Finally, other variants and embodiments are possible, for example cells having a number of chambers different from five, six or more, which are to be considered as included in the scope of protection defined by the following claims.

Claims

Articulated cell (250) for an inflatable mattress, comprising a static portion (262) not directly fed by an inflation and deflation system, and a dynamic portion (260) directly fed by the inflation and deflation system, wherein said dynamic portion (260) comprises a main body having a first volume, said main body being connected to the inflation and deflation system; wherein a cavity (25) having a second predetermined volume is formed inside said main body, so that said dynamic portion (260) comprises a main chamber (27) having a third volume, said first volume being the sum of the second volume and third volume; wherein the cavity (25) is a through cavity and is open towards the ambient outside the cell so that the cavity (25) has a pressure equal to the atmospheric pressure or to the pressure of the ambient outside the cell; characterized by the fact that the dynamic portion (260) and the static portion (262) are connected to each other through a non-return valve (264), said non-return valve (264) allowing the passage of air from the dynamic portion (260) to the static portion (262).
Articulated cell according to the preceding claim, wherein the cavity (25) is formed for the entire length of the main body.
Articulated cell according to one of the preceding claims, wherein the main chamber (27) comprises at least three secondary chambers (54; 254) with lateral edges, said at least three secondary chamber (54; 254) being connected together at their respective lateral edges so as to form a structure which is closed peripherally and in which the through cavity (25) is formed.
Articulated cell according to the preceding claim, wherein the at least three secondary chambers (54; 254) extend in length and are joined together along their longer lateral edges.
Articulated cell according to claim 3 or 4, wherein at least one of the lateral edges of the at least three secondary chambers (54; 254) comprises a conduit (56; 256) allowing the passage of air among said at least three secondary chambers (54; 254).
Articulated cell according to one of the preceding claims, wherein the main chamber (27) comprises a portion of outer surface (26; 52; 252) adapted to go in contact with the person, said portion of outer surface (26; 52; 252) having a contact pressure (Pc2; Pc3; Pc4) with the person, so that said contact pressure (Pc2; Pc3; Pc4) decreases as the volume of said main chamber (27) decreases.
Articulated cell according to one of the preceding claims, wherein the section of the main body is inscribed in a circumference having a first predetermined diameter (H), wherein the section of the cavity (25) is circumscribed to a circumference having a second predetermined diameter (h1), and wherein the second predetermined diameter (h1) is smaller than the first predetermined diameter (H).
Inflatable mattress (10; 100; 200) connected to an inflation and deflation system and adapted to lift a person, comprising:
- a first series of inflatable cells (12; 112; 212);

- at least one second series of articulated cells according to one of the preceding claims;

- a valve (16; 116; 216) connected to the first series of inflatable cells (12; 112; 212) and to the at least one second series of articulated cells (250) through a feeding tube (18; 118; 218);
said valve (16; 116; 216) being connected to the inflation and deflation system at a first pressure;
said first series of inflatable cells and said at least one second series of articulated cells (250) being disposed adjacent to each other, so that all are adapted to lift a person.
Inflatable mattress (10; 100; 200) according to the preceding claim, wherein the at least one second series of articulated cells (250) has a lower contact pressure than the contact pressure of the first series of inflatable cells (12; 112; 212), so that the at least one second series of articulated cells (250) may be disposed in correspondence of areas of the body of the person which need a lower contact pressure than the areas of the body of the person which are supported by the first series of inflatable cells (12; 112; 212).