EP0721755A1 - Inflatable telescopic cells for cushions and matresses - Google Patents

Abstract

The present invention elates to inflatable cells for cushion and mattress elements, and in particular for medical applications, the elements comprising a soleplate that has a bottom support surface that is plane plus said telescopic cells that extend perpendicularly from and that are fixed to said soleplate in a matrix that covers the top surface of the element, each cell being made out of a flexible material forming an airtight external skin that encloses an internal volume, each of which is in communication with the internal volume of at least one adjacent cell. According to the invention, each of the lateral surfaces in a first opposite pair of lateral surfaces constituting each cell comprises three vertical flats that in the rest position form two concave edges, whereas the other two lateral surfaces of the cell comprise two vertical flats that form a single concave edge in the middle, with at last one of the three-flat lateral surfaces of any one cell facing a two-flat lateral surface of an adjacent cell.

Description

The present invention relates to new inflatable cells, called telescopic, cushions and mattresses.

The technical sector of the invention is that of the production of cushions and mattresses for receiving seated or lying people.

One of the main applications of the invention is the manufacture of such cushions or mattresses for medical use to help prevent bedsores.

We know in fact such cushions or mattresses made by the juxtaposition of inflatable cells, from a lower orifice which is then closed, fixed and communicating with each other by a support making sole and support for the whole of the cushion or mattress; said cells are elongated, vertical, perpendicular to said support flange, arranged next to each other, made of flexible and sealed material, and their external shape is of the mandrel type, preferably with four faces, which each form a hollow even pre-inflated in the rest position, either in the absence of support on said cushion or mattress.

When a person sits or lies down on said cushion or mattress, said cells are crushed and their initially hollow side walls deform under this pressure, and come into contact with those of adjacent cells, until their walls also join together and form a quasi-continuous surface receiving in support that of the part of the body of the person, and taking the shape of this one; all the cells being at the same internal pressure, their differences in volume compensate for each other.

Such structures called multicellular or telescopic cells, are known and developed by many manufacturers, including one of the oldest Mr. Robert H. GRAEBE, filed a patent application on May 16, 1973 in the UNITED STATES, issued March 11, 1975 No. 3,870,450; then thereafter various improvement patents from this basic patent, such as patent US4,541,136 of September 17, 1985 relating to the shape of cells with four convex external edges and four concave median edges, delimiting between them eight sides forming at the same time four sides, with hollow surface, and four fins, the whole being of characteristics symmetrical with respect to the central axis; then patent US4,698,864 of October 13, 1987 relating essentially to the possibilities of different heights of certain cells with respect to each other, depending on the position of the seat; then US Pat. No. 5,052,068 of October 1, 1991 relating to an improvement equivalent to the previous one, with cells always symmetrical with eight sides forming four fins and four concave edges in the middle of their four faces, but with different shapes; and finally PCT patent WO 92 / 07.492 published on May 14, 1992 and relating to a distribution of air or gas which can swell said cells, through a manifold which can distribute this air or gas in certain cells to allow different pressures, depending on the areas of the cushion or said mattress.

Such mattresses have been the subject of a certain number of embodiments, within the framework of the first patents cited above, but which on the one hand initially and only protected the American territory, and which, on the other hand for the first at least is in the public domain since, even on this territory.

Different standards also exist in certain countries, to define the minimum characteristics of such cushions or mattresses, such as those in FRANCE established by the Regional Health Department, with in particular minimum crushing requirements imposing for example: a greater thickness or equal to 2 cm at the subject's body, and 3 cm at the thighs for someone lying on said mattress; an easy and quick possibility of repair in the event of a tear, since any leak prevents a minimum pre-inflation of the mattress to ensure a support effect by a minimum degree of inflation depending on the weight of the person; a thickness of between 600 and 800 µ for the material constituting the cell wall of said cushion or mattress, and between 700 and 900 µ for the base or sole thereof, with a resistance to rupture in both directions greater than 15 MPa and an elongation, also at break in both directions, greater than 700%; an outfit to the pressure of 50 millibars for more than 48 hours, and allowing, after 24 hours of crushing by a mass of 90 kg distributed on a wooden board of 35 cm x 35 cm for a cushion of equivalent dimensions, to maintain more than 2 cm thick of it.

Thus, to meet these standards, while providing maximum comfort and optimum manufacturing in order to obtain the lowest possible cost price, especially in countries where social organizations allow coverage and reimbursement capped of such cushions or mattresses, various manufacturers have developed different manufacturing methodologies with different cell shapes and material compositions, as well as some improvements to improve and distinguish themselves from the cushions of competitors, but most still have certain faults and drawbacks such as: instability of the pre-swollen cells which can then lie down when the patient leans and / or moves on the cushion or mattress, which destroys the effect and the advantage of these poor transmission between the internal air volumes cells which, especially when the person is moving, does not allow a good distribution of the pressure which is not then more constant; an imperfect collage of the various elements; flexibility of the material too sensitive to temperature, and often too great a stiffness of this material due to the techniques of manufacturing by quenching; great difficulties, if not impossible to repair in the event of a leak; poor ventilation and external air circulation between cells ...

The problem is therefore to be able to manufacture a cushion or mattress with so-called telescopic cells, made of a material, constituting their skin, as flexible as possible, and whose flexibility is insensitive to temperature, the shape of said cells having to ensure their good vertical stability with homogeneous crushing and simultaneously always uniform inflation with correct pressure distribution; moreover, the arrangement of the cells must allow good movement of air from one cell to another during the movements of the person supported on the cushion or the mattress, while optimizing the manufacture thereof to obtain a cost. minimum, and guaranteeing their good performance and repair possibilities.

A solution to the problem posed is a telescopic cell inflatable with a cushion or mattress element, consisting of a sole providing a flat lower support surface and of several said cells, elongated perpendicularly and fixed to said sole, arranged parallel to each other in a matrix covering the surface of the element and made of flexible material forming a sealed outer skin containing an internal volume of gas in each cell, each communicating with at least the internal volume of an adjacent cell; which cells are in the form of a mandrel with four external edges, the four lateral surfaces of which are in the recessed recessed position, and when a load is applied to said element by pressing on the ends of cells which then crash vertically, said surfaces deform until they come into contact and lean on those of adjacent cells. According to the invention, two of the opposite lateral surfaces of each cell consist of three vertical sides forming in the rest position, two concave edges, while the other two lateral surfaces of the same cell consist of two vertical sides forming a single concave edge median, at least one of the three-sided side surfaces of each cell being disposed facing a two-sided side surface of an adjacent cell.

Preferably, the dimensions of said cells have a ratio between their base and their height depending on the thickness of the cushion desired, between either 37 and 45% for an average height between 95 and 105 mm, or between 57 and 65% for a height between 60 and 70 mm, and a distance between their bases of at least 8 mm, with a cell density per m ² between 350 and 450; the angle a formed by the only two inclined sides of the lateral surfaces of each cell which they constitute is 120 ° and moreover the vertical sides of all the lateral surfaces are articulated at their lower parts on inclined sides which articulate themselves on a cylindrical base.

In a preferred embodiment, said material constituting the skin of the cells has a thickness of 6 / 10ths of a mm plus or minus 1 / 10ths and made from polychloroprene latex loaded with less than 25% of mineral matter with a mixture of two types of elastomer in proportion of 40 to 60% each to constitute a 100% mixture: one can choose for example two types of neoprene referenced in a standard way among the products manufactured by DU PONT DE NEMOURS, such as Neoprene 671 and Neoprene 750; such choices ensure a minimum degree of crystallization, which guarantees great flexibility of the finished product at any temperature - whereas normally polychloroprenes lose their elastic qualities below 10 ° C - for which manufacturers have added, to date, rather oil to keep the flexibility even when cold, but this addition then decreases the strength properties of the material, with in particular a decrease in the tensile strengths of the bondings.

Furthermore, to ensure the inflation of a cushion or mattress element, at least one of said cells preferably located in a corner of this element, comprises an inflation nozzle fixed and opening into one of the external edges of said cell and located at a distance from the base thereof, either in fact from the sole of the element or the cushion, of at least 8 mm.

It is known that the communication of the internal volumes of the cells is carried out by a balancing channel located at the level of the sole, that which can be obtained by the absence of bonding of the skin of the cells on the latter at given locations at their junction. ; in the present invention, in order to obtain the slowest and gradual air movement possible during movements of a person on said cushion or mattress, and thus to avoid instability as in certain current cushions, said channel, at less in the direction of a dimension of the cushion or of said mattress is such that it connects at most only three adjacent cells in a straight line, and that any part of this channel joining two cells situated on two opposite sides with respect to said dimension of the element passes at least through 3n / 2 cells, n being the number of cells occupying this dimension of the cushion or mattress.

In a preferred embodiment, for a cushion element for example with a dimension of 400 x 450 mm, it can comprise 72 cells at most, arranged in matrices of 8 x 9 for example; the different skins of material, constituting the cells and the sole, are bonded together according to a breaking tensile force equal to the same sample section at least at 40% of that of the material alone constituting said skins, such as in particular thanks to the specific choice of said material, an example of which is given previously.

The result is new types of inflatable telescopic cells of cushion and mattress elements, having a number of features that address the problem.

Indeed, the asymmetrical shape and specific profile of the telescopic inflatable cells according to the invention, and the ratio of their dimensions and their density to m ² , allow these said cells to be more stable than in current cushions or mattresses, which ensures good stability of the load and therefore of the person who can lean on and move on it, while respecting the standards imposed in this area.

In fact, the ten-sided configuration of all the faces of the cells constituting six concave edges instead of four, in the cells known to date, provides better support by a sort of nesting of these with each other. available in staggered rows facing a two-sided side surface of a cell, a three-sided side surface of the adjacent cell: said surfaces are then better immobilized with respect to each other and ensure better stability of the cells than in current cushions; all the more so since the ratios of the dimensions of the cells and their density to m ² are in different percentages, which represents, for the current cushions, cells that are much more vertically elongated, and thus causing a certain instability; in addition, the minimum space retained in the present invention between said cells, which is at least 8 mm and at best 10 mm, is possible thanks to the choice of dimensional ratios as indicated above, this minimum space then being sufficiently wide, allows on the one hand, good ventilation and cleaning, and a better possibility of manufacture by dipping and pouring the product in molds.

Furthermore, the choice of the above polychloroprene material makes it possible to obtain better resistance to quenching, during the processing and molding of said skin to produce said cells, which allows flexibility of the material to be preserved, whereas for many current cushions, the skin is fairly stiff after manufacture; in the present invention, this flexibility is in particular obtained thanks to the minimum mineral load in the polychloroprene retained; moreover, this characteristic of flexibility and that obtained even when cold as already mentioned previously by a choice of mixture of two types of elastomers, as well as the tensile strength of the material, are preserved, even after aging for example for seven days at 70 ° C, with an elongation at break of more than 650%, a tensile strength greater than 15 MPa, while under the same conditions, many other materials harden, which is troublesome, of a part for the user and, on the other hand, during manufacture for bonding the skin constituting said cells on the support sole.

The particular realization also of the communication and connection of the internal volumes of the cells between them, thanks to an elongation of the communication circuits between them, allows to distribute the pressure in a slower way by displacement of air of a cell to the other, in particular in the event of movement of people on it, which confirms the quality of stability indicated above.

We could cite other advantages of the present invention, but those mentioned above already show enough to prove its novelty and interest.

The description and the figures below represent an exemplary embodiment of the invention, but are in no way limiting: other embodiments are possible within the scope and scope of this invention.

Figure 1 is a perspective view of a cousin element according to the invention in pre-inflated situation.

Figures 2 and 3 are side and sectional views of two adjacent cells, according to the invention, of a cushion element.

Figure 4 is a partial view of an element of the cushion of Figure 1 in the rested and deflated position.

FIG. 5 is a top view of the part of the cushion in FIG. 4.

Figure 6 is a bottom view of the sole of a cushion element according to the invention.

The various attached figures represent complete elements of cushions or mattresses or only parts of these elements, knowing that, as shown in Figures 1 or 6, it these are cushions which can be of the order of approximately 400 to 450 mm, and therefore usable in isolation to constitute a cushion placed on any seat; by joining several of these elements together by any connection system, it is possible to form much larger surfaces, constituting for example a mattress on which a person can lie down.

Such a cushion or mattress element therefore consists, in a known manner, of a sole 3, offering a flat surface for lower support, and of telescopic cells 2, elongated perpendicularly, and fixed to said sole, arranged parallel to each other. to each other in a matrix, covering the surface of the element 1, and made of flexible material, forming a sealed outer skin 9, containing an internal volume 4 in each cell; these different internal volumes 4 each communicate with at least the internal volume of an adjacent cell, and said cells 2 are in the form of a mandrel with four external edges 14 and whose four lateral surfaces 5 are in the rest position, as shown in the FIG. 4, in hollow: when a load is applied to said element 1 by pressing on the ends 10 of cells 1, which then collapse vertically, said surfaces are deformed until they come into contact 6, as shown in Figure 1, although in this figure, said load not being shown, this deformation is obtained by pre-inflation; beyond their contact, said surfaces 6 then rely on those of adjacent cells.

FIGS. 2 and 3 are views in profile and in section of this profile of two adjacent cells 2 of a cushion element, as shown in FIG. 1, but in a deflated situation, as in FIGS. 4 and 5.

Said cells 2 thus in the rest position without pre-inflation, therefore have their lateral surface 5 hollow, and which, being four in number, form four-sided mandrels, said internal volumes 4 being in position of minimum dimension.

As can be clearly understood in the top view of FIG. 5, two of the opposite lateral surfaces 5 ₁ of each cell 2, consist of three vertical faces 12 ₁ forming in the rest position two concave edges 13 ₁ , while the two other lateral surfaces 5 ₂ of the same cell 2, consist of two sides 12 ₂ vertical, forming a single median concave edge 13 ₂ ; at least one of the lateral surfaces 5 ₁ with three sides 12 ₁ of each cell is arranged facing a lateral surface 5 ₂ with two sides 12 ₂ of an adjacent cell, according to an arrangement which can be said in staggered rows.

In Figure 3, it is easily understood that by inflating the internal volume 4, thanks to a supply and balancing channel 8 located in the thickness of the sole 3, which transmits air is blown in by end piece 7, either from neighboring cells when a pressure or a weight P is taken over the ends 10 of said cells, the walls 5 of these deviate from the axis of each cell up to '' to approach the surfaces 5 of the adjacent cells: at equilibrium of the external pressure P transmitted by the load to be supported, and the internal pressure of the cells, all of these surfaces 5 are in contact and are supported by with each other, thus with the edge 13 ₂ of the two-sided face of a cell which is housed between the two concave edges 13 ₁ of the three-sided surface of the adjacent cell, thus ensuring better immobilization of the cells together; the final heights of each cell correspond to the external shape of the load supported on said cushion element, which thus follows its profile without local overpressure and punctual overload, which makes it possible to avoid bedsores.

As shown in FIG. 5, in a particular embodiment, the angle α formed by the only _two inclined faces 12 ₂ of the lateral surface 5 _{2 which} they constitute, is 120 °, while the angle formed then between them by the external vertical faces 12 ₃ of the three-sided surfaces, is 60 °.

As shown in Figures 2 and 3, the vertical sides 12 ₁ and 12 ₂ of the side surfaces 5 ₁ and 5 ₂ of each cell 2, are articulated at their lower part on inclined faces 15 ₁ , 15 ₂ which are articulated themselves on a cylindrical base 16, all the more ensuring better stability of the base of said cells with respect to the sole 3 which carries them, whatever their inflation pressure; this configuration also reduces the risk of tearing at the angles which are deformed by the play of pressure variations, and even in the event of a possible leak, this allows better repair since none of the angles of the articulations of the sides of the deformable surfaces, relative to each other, are located on the sole 3, at which a repair is much more difficult to achieve.

Likewise, and inter alia for a similar objective of lower risk of tearing, at least one of the cells 2, such as in particular that situated in a corner of the cushion element, comprises the inflation nozzle 7, fixed and opening into one of the external edges 14 of said cell 2, and located at a distance h from the base thereof, at least 8 mm and is in fact preferably at the top of the height of the cylindrical base 16 vertical of the cell.

In Figure 1, there is therefore shown said cells 2 pre-inflated with this inflation tip 7 located in the corner of the cell, itself located in the corner of the cushion element, but this tip could be of course located in the sole 3, as exists in other cushions, although this embodiment is not recommended according to the present invention; the pre-inflation at a given pressure is, for normal use, determined as a function of the weight of the load that said cushion or mattress element will have to bear, in order to respect for example a minimum height of 3 cm as specified in French standards, when said cells are deformed to the maximum; the internal pressure in them then compensates for the weight they have to bear. In addition, said cells, thanks to the arrangement and the specific shape of their surfaces which come into contact, have good stability; it is obvious however that, if the cells were not swollen enough and did not come into contact with each other, despite their specific arrangement according to the invention, this would cause deviations of their vertical axis, therefore an instability and a bad comfort, and a risk of creating bedsores. The choice of these pressures as a function of the weight of the load can be determined in a known manner, without it being necessary to describe any more in the present description.

According to the invention, in order to guarantee all the more optimum stability of the different cells with respect to each other, and better support between them to distribute the load, said dimensions of cells 2 have a ratio between their base B and their height H of between 57 and 65% for elements of cushions of thin type, that is to say between 60 and 70 mm in the rest position, and a distance "d" between their base of at least 8 mm, with a density of cells per m ² between 350 and 450; when it is desired to have substantial thicknesses of cushions, that is to say between 95 and 105 mm and therefore to have higher cell heights, the above ratio is included in the present invention between 37 and 45%.

Thus by way of example, the base B of cells 2 can be a square of 38 to 42 mm on a side, and their height for cushion elements of small thickness of 65 mm, and for large thicknesses of approximately 100 mm .

Figure 4 is a partial view of the cushion of Figure 1, but in the rested and deflated position, such as the cells shown in Figures 2 and 3, and Figure 5 is a top view of this same cushion part of the FIG. 4 in which is shown, in dotted lines, the balancing channel between said cells 2, which can be produced in a known manner by a grid preventing the bonding of the sole 3, with the skin 9 of the cells at the level of their junction 11.

As indicated previously, in order to slow down the balancing effect of the cells with respect to each other by air transmission between them and therefore to have better stability in the event of movement of the persons seated or lying on said cushion elements or mattress, said channel 8, as shown in FIG. 6, at least in the direction of the general dimensions of the cushion or of said mattress, is such that it connects at most only three adjacent cells 2 in a straight line; moreover, any part of this channel 8 joining two cells 2 situated on the two opposite sides with respect to said dimension of element 1, pass at least through 3n / 2 cells, n being the number of cells occupying this dimension.

In the case of a rectangular cushion as shown in the examples of the attached figures, said dimensions are therefore its width and its length, and the corresponding matrix formed by the cells can be of the 8 × 9 type, ie 72 cells 2 , the shape of which is a four-sided mandrel, as shown in FIGS. 1 to 5.

Thus, in the lengthwise direction therefore comprising 9 cells, the ratio (3n / 2 = 27): 2 = 13.5, or in fact at least 14 cells, which can be verified on any of the four connections going, on figure 6, from the left towards the right, of which the two higher and lower connections connect 15 cells between them and the two median connections connect well 14 cells.

In the width direction, that is vertically in figure 6, there are 8 cells, and the ratio 3n / 2 = 12, which the two left and right end connections of this figure 6 between the lower part do well shown in this figure and the upper part across the width of the element 1.

As indicated above, the material constituting the skin 9 of the cells is preferably 5 to 7 / 10th mm, or at best 6 / 10th mm, thick and produced from a mixture of two type polychloroprene latexes. "neoprene" loaded with less than 25% mineral matter: in addition to the qualities already indicated above by such a choice of materials, with in particular better resistance to quenching during the manufacture by molding of said skin to obtain the particular shape of the cells 2 defined above, a better bonding is also obtained between the different skins constituting the cells 2 and the sole 3: in particular a tensile tensile force equal to the same sample is obtained at least at 40% of that of the material alone constituting said skins. During tests carried out according to French standard NF T 54 122, that is to say by pulling on strips cut from skins glued together and of width 25 mm, which are subjected to a traction of at least 60N , that is to say in fact in the tests carried out, of 70N, it was possible to obtain a result of 61.8% of tensile strength at break relative to the breaking force obtained with the single material not bonded.

Other tests were also carried out, according to various other standards, on such a material, and made it possible to obtain a breaking strength greater than 15 MPa, that is to say 19 MPa, with an elongation at break greater than 700. %, and even up to 820%; and in temperature after aging for 7 days at 70 ° C., a breaking strength greater than or equal to 17 MPa, and an elongation at break still greater than or equal to 650%.

The gas permeability coefficients of the neoprene thus defined is at 25 ° C for hydrogen of 10.8 x 10 ^-8 cm ² / second x atmosphere, for oxygen of 3 x 10 ^-8 cm ² / second x atmosphere, for nitrogen 0.89 x 10 ^-8 cm ² / second x atmosphere, and for carbon dioxide 19.4 cm ² / second x atmosphere; and at 50 ° C, the same gases with the same units, allow to obtain respective permeability coefficients of 28.5, 10.1, 3.5, and 56.5 cm ² / second x atmosphere.

Claims (10)

Inflatable telescopic cells (2) of cushions and mattress elements (1) consisting of a sole (3) providing a lower flat support surface and of several said cells (2), elongated perpendicularly and fixed to said sole ( 3), arranged parallel to each other in a matrix covering the surface of the element (1) and made of flexible material forming an external skin (9) sealed enclosing an internal volume (4) in each cell, each communicating with at least the internal volume of an adjacent cell, which cells (2) are in the form of a mandrel with four external edges (14) and whose four lateral surfaces (5) are in the recessed position, and when a load is applied to said element (1) by pressing on the end (10) of cells (1) which then collapse vertically, said surfaces are deformed until they come into contact and bear on those of adjacent cells, characterized in that of them opposite lateral surfaces (5 ₁ ) of each cell consist of three vertical faces (12 ₁ ) forming, in the rest position, two concave edges (13 ₁ ), while the other two lateral surfaces (5 ₂ ) of the same cell are consisting of two vertical faces (12 ₂ ) forming a single median concave edge (13 ₂ ), at least one of the three-sided lateral surfaces (5 ₁ ) (5 ₁ ) of each cell being arranged facing a lateral surface (5 ₂ ) with two sides (12 ₂ ) of an adjacent cell. Inflatable cells according to claim 1, characterized in that their dimensions have a ratio between their base (B) and their height (H) between 37 and 45%, for a height (H) between 95 and 105 mm, and a distance (d) between their bases of at least 8 mm, with a cell density per m ² of between 350 and 450. Inflatable cells according to claim 1, characterized in that their dimensions have a ratio between their base (B) and their height (H) of between 57 and 65% for a height (H) of between 60 and 70 mm, and a distance (d) between their base of at least 8 mm, with a cell density per m ² of between 350 and 450. Inflatable cells according to any one of claims 1 to 3, characterized in that the material constituting the skin (9) of the cells (2) is 5 to 7 / 10ths of a mm thick and made from polychloroprene latex loaded with less than 25% mineral matter. Inflatable cells according to any one of claims 1 to 4, characterized in that at least one comprises an inflation tip (7) fixed and opening into one of the external edges (14) of said cell (2) and located at a distance (h) from the base of the cell of at least 8 mm. Inflatable cells according to any one of Claims 1 to 5, characterized in that the angle (α) formed by the only two inclined faces (122) of the lateral surface (52) of each cell is 120 °. Inflatable cells according to any one of claims 1 to 6, characterized in that the vertical sections (12 ₁ , 12 ₂ ) of their lateral surfaces (5 ₁ , 5 ₂ ) are articulated at their lower parts on inclined sides ( 15 ₁ , 15 ₂ ), which articulate themselves on a cylindrical base (16). Cushion and mattress elements (1) constituted by cells (2) according to any one of claims 1 to 7, and in which the communication of the interior volumes (4) of the cells (2) is carried out by a channel balancing (8) located at the level of the sole (3), characterized in that said channel (8), at least in the direction of a dimension of the cushion or said mattress, is such that it only connects a maximum of three cells (2) adjacent in a straight line, and that any part of this channel (8) joining two cells (2) located on two opposite sides with respect to said dimension of the element (1) passes at least through 3n / 2 cells , n being the number of cells occupying this dimension. Cushion or mattress elements (1) consisting of cells (2) according to any one of claims 1 to 7 and of dimensions 400 x 450 mm at most approximately, characterized in that said element (1) comprises 72 cells (2 ) arranged in 8 x 9 matrices. Cushion or mattress elements (1) consisting of cells (2) according to any one of claims 1 to 7, characterized in that the various skins constituting the cells (2) and the sole (3) are bonded together according to a breaking tensile force equal to at least 40% of that of the material alone constituting said skins.

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