EP0041037B1 - Anti-bed sores individual pillows and mattresses as well as manufacturing process - Google Patents

Description

The subject of the invention is anti-decubitus cushions and methods of manufacturing them.

We know that people who are forced to sit for a long time in a sitting or lying position, especially the handicapped and paralytic people who are forced to sit in a chair, are exposed to the risk of pressure sores which are pressure ulcers resulting from prolonged compression of the tissue that prevents blood from flowing, which causes necrosis and then decay of the infected tissue.

Paraplegics do not feel pain in the compressed region and, as a result, they are even more exposed to the formation of pressure sores. The most threatened areas are those where a bone or bony protrusion is located close to the skin in an area that supports the weight of the body.

The risk of pressure ulcers exists particularly for paralyzed lower limbs who must remain in a seated position, since almost the entire weight of the body compresses the flesh which forms the coxal bone and which are located on either side of the sacrum.

The formation of sores in the seat leads to months of hospitalization in a lying position to achieve healing of the ulcer, and treatment sometimes requires surgical excision of necrotic tissue, resulting in high costs.

In the following description, we will mainly describe the devices intended to avoid bedsores in the seat and these devices will be designated by the term anti-decubitus cushions. It is specified that the term "cushion is used in a non-limiting sense to also designate anti-decubitus devices which can be located on a chair backrest and also anti-decubitus mattresses intended to support patients immobilized in the lying position. Likewise the term seat of the body is used in a general sense to designate any part of the body which takes on a cushion, a backrest or a mattress.

Cushions and anti-decubitus mattresses are already known which consist of inflatable bags or of bags filled with a liquid or a gel, or cushions or mattresses made of cellular material.

The FR patent. A. 2.277.555 (HERMAT) describes for example an anti-decubitus mattress composed of several layers of cellular materials with open or closed cells.

All of these known cushions and mattresses are easily deformable so that they conform perfectly to the shape of the body and that the weight of the body is distributed over the largest possible support surface. However, these known devices have drawbacks. Air bags or bags filled with a liquid or gel are necessarily waterproof envelopes, so that the support area of the body is not ventilated and heats up. Cellular foam cushions flatten over time and the material loses elasticity.

Cushions are also known for cushions composed of a fibrous material, mixed with latex.

The BE-A patent. 373.561 (A. WEBER et AI) describes cushions composed of a cover and a fiber padding which are impregnated with latex or any other similar elastomeric substance.

The US patent. A. 2,866,497 (W. STRUTHERS) describes cushions comprising a cover, a rigid bottom, a layer formed from a mixture of fibers and polyurethane foam and a layer of polyurethane foam.

The cushions described in these two prior patents are not anti-decubitus cushions.

The objective of the present invention is to provide new anti-decubitus cushions and mattresses intended for the light handicapped persons who are obliged to remain in a wheelchair for periods of limited duration and personalized anti-decubitus cushions intended for the handicapped persons constrained to keep a sitting position or elongated, which cushions and mattresses are deformed in an elastic manner by marrying the shape of the seat of the body while ensuring good ventilation of the contact area.

The cushions according to the invention are intended to be removably placed on an armchair seat and are of the type comprising a cover furnished with padding, breathable, composed of fibrous materials impregnated with natural latex which has been crosslinked .

The object of the invention is achieved by means of anti-decubitus cushions, characterized in that the latex is added to the fibrous materials in proportions of between 30% and 50% of the total weight of the padding and the cushion also comprises , a rigid base plate which is placed inside said cover under said padding.

Advantageously, the padding is composed of two superimposed layers: an upper layer of animal hair and a lower layer of vegetable fibers and the thicknesses of the upper layer and the lower layer are respectively of the order of one third and two thirds of the total thickness.

According to a first embodiment, a cushion according to the invention comprises a base plate in the form of a rigid shell comprising a perforated bottom, two side edges and a rear edge directed upwards which have a height substantially equal to that of the padding that 'they surround.

According to another embodiment, a cushion according to the invention intended more particularly for folding armchairs, comprises a rigid base plate having two side edges directed upwards, having a height of the order of a few centimeters, which frame the padding.

A personalized cushion according to the invention further comprises a perforated plate, made of a flexible material, which matches the shape of the user's seat and which is placed on the upper face of said padding which has been shaped for also conform to the shape of the user's seat.

• - on forme une nappe de crins animaux et une nappe de fibres végétales ayant une épaisseur cumulée légèrement supérieure à l'épaisseur finale des coussins ;
• - on pèse les deux nappes et un poids de latex naturel tel que la proportion de latex soit compris entre 30 % et 50 % du poids total ;
• - on pulvérise la moitié dudit latex sur l'une des faces de ces deux nappes et on sèche les nappes à une température de l'ordre de 80 °C ;
• - on retourne les deux nappes, on pulvérise l'autre moitié du latex sur la deuxième face et on sèche à une température de l'ordre de 80 °C ;
• - on fait passer les deux nappes entre deux cylindres d'une calandre pour leur donner l'épaisseur voulue ;
• - on fait séjourner les deux nappes dans une étuve à une température de l'ordre de 145 °C pendant une durée de l'ordre de quarante-cinq minutes pour réticuler le latex ;
• - on découpe dans les nappes des blocs aux dimensions des coussins, on superpose un bloc de crins imprégnés (11) sur un bloc de fibres imprégnées (10) et on les solidarise par collage ;
• - on pose l'ensemble des deux blocs superposés sur une plaque de base rigide (2) ;
• - et on place l'ensemble des deux blocs et la plaque rigide dans une housse (12).

A method of manufacturing an anti-decubitus cushion according to the invention comprises the following steps:

• - A sheet of animal hair and a sheet of vegetable fibers having a cumulative thickness slightly greater than the final thickness of the cushions are formed;
• - We weigh the two layers and a weight of natural latex such that the proportion of latex is between 30% and 50% of the total weight;
• - Half of said latex is sprayed on one of the faces of these two plies and the plies are dried at a temperature of the order of 80 ° C;
• - The two layers are turned over, the other half of the latex is sprayed onto the second face and dried at a temperature of the order of 80 ° C;
• - Passing the two layers between two cylinders of a calender to give them the desired thickness;
• - The two layers are made to stay in an oven at a temperature of the order of 145 ° C for a period of the order of forty-five minutes to crosslink the latex;
• - blocks are cut from the plies to the dimensions of the cushions, a block of impregnated hairs (11) is superimposed on a block of impregnated fibers (10) and they are bonded together;
• - all the two superimposed blocks are placed on a rigid base plate (2);
• - And the assembly of the two blocks and the rigid plate is placed in a cover (12).

According to a first embodiment, to shape the upper face of the padding, a mold is filled, the bottom of which reproduces the shape of said personalized molding of a mixture of animal hair or vegetable fibers and of a liquid elastomer binder, said heating is heated mixture to solidify the binder, it is removed from the mold, the padding is turned over and the latter is placed inside the shell.

According to another embodiment, to shape the upper face of the padding, the personalized molding is divided into juxtaposed meshes, blocks of a mixture of animal hair or vegetable fibers and an elastomeric binder corresponding to the dimensions of said meshes are made and cut the upper face of each of said blocks so that it substantially reproduces the profile of said personalized molding inside each of said meshes and then juxtaposes said blocks inside said shell by gluing them together.

The invention results in new products which constitute personalized cushions and mattresses, which perfectly match the morphology of the seat of the body of an individual while allowing to ventilate the contact area thanks to the perforations of the shell and of the top plate and also thanks to the air permeability of the padding.

The cushions and mattresses according to the invention increase the bearing surface of the body and therefore reduce the pressures from which it results that they prevent the formation of bedsores.

The personalized cushions according to the invention can be used not only for handicapped people bound to a wheelchair but also for a better comfort of the individuals who have to stay or work in sitting position for example as seats for professional drivers of vehicle or of workers in position seated.

The following description refers to the appended drawings which represent, without any limiting nature, exemplary embodiments of anti-decubitus cushions according to the invention.

Figure 1 is an exploded view of a personalized anti-decubitus cushion which is composed of three parts placed inside a cover not shown.

Figures 2 and 3 show an exploded perspective view and a sectional view of a second embodiment.

The cushion according to FIG. 1 comprises a rigid shell 1 in the form of a bowl, which is for example a shell molded from polyester or any other equivalent polymer.

This shell 1 has a bottom 2 provided with perforations 3 and rims 4a, 4b which extend the bottom 2 upwards and which surround the lining. In the case of a cushion, the shell 1 has only two side edges 4a and a rear edge 4b. It has no front edge.

The shell 1 is equipped with a handle 5 for transporting the cushion. Of course, the dimensions of the shell 1 are chosen such that they slightly exceed the dimensions of the seat of the body of the individual for whom the cushion is intended.

The interior of the shell 1 is lined with padding 6 which is composed of a mixture of fibers, preferably animal hair or vegetable fibers and latex.

Layer 6 is preferably composed of two superimposed layers as shown in Figure 2.

The density of fibers and binder is chosen so that the padding remains breathable to allow ventilation of the support area of the body. The upper face 6a of the padding 6 is shaped so that it substantially matches the shape of the seat of the individual for whom the cushion is intended. The padding 6 is preferably placed in a sheath 7 made of a fabric of natural fibers, preferably a sheath of flexible terry cloth. The sheath 7 is shown half open.

The thickness of the padding 6 is slightly less than the height of the edges 4a, 4b of the shell.

Above the padding 6 is arranged a shell 8 which is constituted by a plate made of a flexible material provided with perforations 9. The plate 8 has for example a thickness of the order of 10 mm and it is composed of a thermoformable material , for example the material known under the brand “plastazote”, or a flexible silicone such as that which is known under the brand “silastene •. The plate 8 is thermoformed to match on its two faces the shape of the seat of the individual. Thus, the underside of the plate 8 perfectly matches the shape of the face 6a which has itself been shaped to match the shape of the seat and the pressures transmitted by the plate 8 to the padding 6 are distributed uniformly throughout the volume. padding 6.

The shape of the upper face of the plate 8 follows the shape of the seat of the individual and the bearing surface of the body on the plate 8 is maximum.

All three constituent parts 1, 6 and 8 are wrapped in a removable cover which is not shown for clarity of the drawing. This cover is preferably composed of a terry cloth or a plush fabric, elastic and ventilated, resistant up to 120 ° so that it is possible to disinfect it hot and anti-allergic, which constitutes a surface flexible contact with the body and which is flexible enough to perfectly match the shape of the plate.

It happens that certain paralytics are at the same time incontinent. In this case, the cover has, on its upper face, a double wall forming a pocket in which one can slide sheets of cellulosic material forming absorbent layers which are easily deformable and which therefore conform to the shape of the plate 8 when the cushion is busy.

The foregoing description is that of a seat cushion, but it is specified that the same structure can also be applied to cushions intended to garnish the backs of an armchair or to mattresses.

To manufacture a personalized cushion or mattress according to the invention in the factory, it is necessary to have a personalized molding of the seat of the individual for whom the cushion or mattress is intended. Since the anti-decubitus cushions or mattresses are intended for patients who cannot move, it was necessary to develop a process which makes it possible to make on the spot a molding of the seat of an individual using relatively material simple and easy to carry.

In a first step, we take a hollow imprint of the seat of the individual. To obtain this imprint, a deformable waterproof envelope is used which contains a divided material, for example an inflatable envelope made of flexible plastic, which contains small glass beads having a diameter of the order of a millimeter. Then vacuum is gradually made inside the envelope by means of a vacuum pump until reaching for example an absolute pressure in the envelope of the order of 100 millibars. This vacuum presses the envelope against the balls and the envelope keeps the balls in position, so that a hollow imprint of the seat is thus obtained.

In a second step, a sheet of thermoformable plastic material is heated to the temperature at which it softens, which is of the order of 70 ° and the hot sheet is applied to the hollow imprint obtained previously. We then sit the individual on the sheet placed on the hollow imprint and wait for the sheet to cool. The sheet constitutes a personalized double-sided molding of the seat of the individual, easy to transport and it is this personalized molding which is shipped to the factory and which is used to make a cushion adapted to the individual morphology of the user.

The molding is used to shape the upper face 6a of the padding 6 and to thermoform the perforated plate 8, which is shaped directly on the molding.

In order to shape the padding 6 according to a first method, a cup-shaped mold is first made, the bottom of which reproduces the shape of the personalized molding 8 and the height of which is equal to the thickness of the padding 6. The said mold is then filled a mixture of animal hair or vegetable fibers impregnated with liquid latex. We choose a mixture density such that the padding is breathable and that it remains flexible, but does not crush too much under load. The mixture is heated to a temperature sufficient for the latex to solidify. After which we unmold and turn the padding so that the face 6a, which was in contact with the bottom of the mold and which reproduces the imprint thereof, becomes the upper face of the padding and we place the padding in the shell 1 .

According to a second method, to shape the padding 6 the personalized molding is divided into juxtaposed identical meshes, for example square or rectangular meshes.

We make a padding layer of uniform thickness and we cut it into blocks whose horizontal section is equal to the size of the mesh. After which the upper face of each padding block is cut so that it substantially reproduces the profile of said personalized molding inside each of the meshes. This cutting can be done for example by means of a probe which follows the profile of the molding inside each mesh and which is connected to a cutting tool such as a chisel which follows the movements of the probe and which cuts the upper face of each padding block by copying the profile followed by the probe.

Once all the blocks have been made, they are juxtaposed inside the shell 1 by gluing them together.

To make on-site personalized molds for a patient's seat, portable equipment is placed in a case which contains, on the one hand, thermoplastic plates, the surface of which corresponds to that of the largest seats, an inflatable pocket filled with small balls and a small vacuum pump. The inflatable bag can be reused several times. After it has been used to make the double-sided molding of an individual, it suffices to remove the vacuum in the pocket so that the beads are released and the pocket then resumes its initial shape.

Figures 2 and 3 respectively show an exploded view and a cross section of the components of a second embodiment which is a non-personalized bedsore cushion. The parts homologous to those of FIG. 1 are represented by the same references.

This second cushion is a more economical cushion than the previous one, which is intended for the slightly handicapped who have to stay in a wheelchair for a limited period.

It includes a cover 12, made of terry cloth, equipped with closing means, for example with a zipper or an elastic band which make it removable, so that it is possible to wash it separately. The cover 12 is not shown in FIG. 2. The cover 12 envelops both a rigid base plate 2 and a padding 6.

The plate 2 is for example of plastic material having a thickness of the order of one centimeter. It has two side edges 4a directed upwards, having a height of the order of two centimeters, which surround the padding 6. It can be solid or perforated.

The plate 2 has a width and a depth very slightly less than the dimensions of the canvas seat of a folding wheelchair for the disabled on which the cushion is placed.

Plate 2 rests on the seat uprights and it prevents the fabric from bending.

The house 12 also contains a padding 6, which is placed above the base plate 2.

The padding 6 is enclosed in a fabric envelope 7. The padding 6 is composed of two superimposed layers 10 and 11, the thickness of which is equal respectively to approximately two thirds of the height for the lower layer 10 and one third of the height for the upper layer 11.

The upper layer 11, on which the seat of the handicapped person rests, is composed of a mixture of animal hair and natural and crosslinked latex.

The hairs are preferably hairs of beef, horse, pork or goats, which are very flexible hairs, not likely to injure the seat of the disabled person.

The density of the mixture of horsehair and the latex which makes up the layer 11 is of the order of 30 Kg / m ³ , which corresponds to a proportion by weight of crosslinked latex of between 30% and 50% of the total weight of the mixture . This proportion makes it possible to obtain a mixture which is both breathable and sufficiently elastic not to settle and to resume its initial volume when it is no longer compressed by the weight of the occupant of the wheelchair.

The lower layer 10 is composed of a mixture of vegetable fibers and an elastomer which is preferably crosslinked latex. The plant fibers are preferably coconut fibers. The density of the mixture is of the order of 100 Kg / m ³ , which also corresponds to a proportion by weight of crosslinked latex of between 30% and 50% of the total weight of the mixture.

The superimposed layers 10 and 11 which make up the padding have sufficient air permeability for natural ventilation of the seat of the disabled person sitting on the cushion. They also have the essential qualities of flexibility and nervousness. The upper layer in very flexible animal hair has a low density and it allows to distribute the pressures well on all the surface of the seat. The denser lower layer absorbs the shocks transmitted by the wheels of the chair and acts as a suspension.

A method for manufacturing the padding of a cushion according to the invention comprises the following operations. A sheet of animal hair and a sheet of vegetable fibers having a thickness slightly greater than the desired thickness of the layers 10 and 11 of the padding are formed.

Natural latex is sprayed on the upper face of these sheets. The sheets are passed through a dryer at a temperature of the order of 80 ° in order to start solidifying the latex. The sheets are then turned over and latex is sprayed on the second face of these sheets. The tablecloths are again passed through a dryer at a temperature of the order of 80 °.

During these spraying operations, the hairs or fibers are not packed and the liquid latex penetrates into the thickness of the sheets which is of the order of 20 mm to 50 mm.

The impregnated layers are then calendered by passing them between two cylinders whose spacing is equal to the desired final thickness, for example a thickness of 40 mm for the lower layer.

Finally, the tablecloths are left to remain in an oven at a temperature of 145 ° C. for approximately forty five minutes in order to crosslink the latex and to give it its elastic properties.

The quantity of latex which is sprayed on the sheets is determined to obtain a final density of the order of 30 Kg / m ³ for the upper sheet and of the order of 100 Kgf ^I _M ³ for the lower sheet, which corresponds at a proportion by weight of latex of between 30% and 50% of the total weight. A proportion of latex greater than 50% of the total weight would lead to a padding which is not very breathable and unnecessarily expensive.

A proportion lower than 30% gives a padding which lacks elasticity and which tends to settle.

Once the tablecloths have been prepared in strips by the process which has just been described, rectangles or squares are cut from these strips. dimensions of the cushions and a layer of impregnated hairs is joined by gluing with a layer of impregnated fibers.

An adhesive based on latex or elastomer which impregnates the fibers and the hairs is advantageously used for this bonding.

Claims (10)

1. Anti-eschar cushion designed to be placed in removable manner on a seat, of the type comprising a protecting cover (12) stuffed with an airtight padding (6) composed of fibrous material impregnated with natural latex which has been reticulated, characterized in that said latex is added to said fibrous material in proportions varying between 30 % and 50 % of the total weight of the padding, and said cushion further comprises a rigid supporting plate (2) which is placed inside said protecting cover under said padding.

2. Cushion according to claim 1, characterized in that said padding (6) is constituted by two superposed layers : an upper layer (11) in animal hair and a lower layer (10) in vegetable fibers, and the thicknesses of said upper layer (11) and of said lower layer (10) are respectively around one third and two thirds of the total thickness.

3. Cushion according to claim 2, characterized in that said upper layer (11) is in pig's, oxe's, horse's or caprine's hair and has a voluminal mass of about 30 kg/m³ after impregnation and said lower layer (10) is in coconut fibers and has a voluminal mass of about 100 kg/m³ after impregnation.

4. Cushion according to claim 1, characterized in that said supporting plate (2) is a rigid shell, comprising a perforated bottom and two lateral edges (4a) and a rear edge (4b) which are upwardly directed and have a height substantially equal to the thickness of the padding they surround.

5. Cushion according to claim 1, characterized in that said supporting plate (2) comprises two lateral edges (4a) upwardly directed, with a height of about a few centimeters framing the said padding.

6. Personnalized cushion according to claim 4, characterized in that it further comprises a perforated plate (8) in supple material which takes the exact shape of the sitting position of the user's body and which is placed on the upper face of said padding (6) which has been shaped so as to also take the shape of the user's sitting position.

7. Process for manufacturing anti eschar cushion, characterized by the series of following operations :

- a layer of animal hair and a layer of vegetable fibers are formed, having a cumulated thickness slightly greater than the final thickness of the cushion ;

- the two layers and a weight of natural latex are weighed so that the proportion of latex be between 30 % and 50 % of the total weight ;

- half of said latex is sprayed on the second face and the layers are dried at a temperature of about 80° ;

- the two layers are turned over, the other half of latex is sprayed on the second face, and it is dried at a temperature of about 80°;

- the two layers are caused to pass between two cylinders of a calender to give them the desired thickness ;

- the two layers are left to stand in an oven at a temperature of about 145 °C for about 45 minutes to reticulate the latex ;

- blocks of the size of the cushions are cut from the layers, a block of impregnated animal hair (11) and a block of impregnated fibers (10) are superposed and adhesively jointed together ;

- the assembly of the two superposed blocks is placed on a rigid supporting plate (2) ;

- the assembly of the two blocks and the rigid plate is placed in a protecting cover (12).

8. Process according to claim 7 for manufacturing a personnalized anti eschar cushion according to claim 6, characterized in that in addition ;

- an imprint of the sitting shape of the body of an individual is taken by sitting said individual on a deformable airtight enveloppe containing a divided material and by creating a vacuum inside said enveloppe ;

- a sheet of thermodeformable plastic material is heated and is applied on said imprint and said individual is sat on said sheet put on said imprint until said sheet cools down, which sheet constitutes a personnalized reversible moulding of the sitting position which can be sent to the factory manufacturing the cushion ;

- a rigid bowl shaped supporting place (1) is manufactured in factory, comprising a perforated bottom (2) and edges (4a, 4b), the dimension of which slightly projects from those of said personnalized mould ;

- said assembly of two padding blocks (10, 11) is placed in said bowl, and the upper face of said padding is shaped so that it substantially takes the shape of said personnalized moulding ;

- a thick and perforated plate (8) of a supple and thermodeformable material is shaped on said personnalized mould ;

- said plate (8) is placed on said padding and the assembly constituted by said bowl, said padding and plate, is placed inside a protecting cover (12).

9. Process according to claim 8, characterized in that in order to shape the upper face of said padding, a mould whose bottom reproduces the shape of said personnalized moulding is filled with a mixture of animal hair, or vegetable fibers, and of a liquid elastomer binder, said mixture is heated in order to solidify the binder, and is then removed from the mould, said padding is turned over and is placed inside said shell.

10. Process according to claim 8, characterized in that, in order to shape the upper face of said padding, said personnalized mould is divided into identical sizes placed side by side, blocks of a mixture of animal fibers or vegetable fibers with an elastomer binder corresponding to said sizes are constituted, and the upper face of each of said blocks is cut out so as to substantially reproduce the shape of said personnalized moulding inside each of said sizes, and said blocks are thereafter juxtaposed inside said shell, being adhesively jointed together.

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