FR2689004A1 - Inflatable mattress construction for preventing bedsores - has cellular construction defined by elongate rectangular-section chambers, formed by parallel weld lines between adjacent flexible sheets - Google Patents

Abstract

The mattress is formed by a pair of sheets (1,2) welded together around their periphery, with a number of additional weld lines (6) defining connected parallel internal cavities (10). The sheets are folded to define a series of asymmetric pleats (11) parallel to the additional welds. On inflation of the mattress, the pleats inflate to define parallel chambers of approximately rectangular cross-section, whose walls (13,14) approach closely those of adjacent chambers. The dimensions of the pleats are such that their uninflated width divided by their inflated width is within 10 per cent of the constant value pi/2. ADVANTAGE - Avoids formation of stress concentration points between patient's skin and mattress surface.

Description

The invention relates to the improvement of an anti-decubitus mattress and the method of obtaining it.

Anti-decubitus mattresses have been available for a long time, but they have drawbacks which it is important to correct, such as, for example, the level of comfort, solidity and shortness of manufacture. The anti-decubitus mattress must have the flattest surface possible; it is filled with water so as to obtain the best possible distribution of the pressures on the body of the patient who rests there; but it must also be concluded to ensure rapid balancing of the pressure of the water in the mattress, associated with a small displacement of the wall supporting the load which is placed therein, in order to avoid that by displacement of the water the two lower and upper walls come into contact and cause occasional overpressures on the patient's body which can be very painful.

Mattresses, which are on the market, are formed of two films welded together, preferably7 by high frequency welding on plastic materials comprising radicals sensitive to electromagnetic resonance and they mainly comprise a pocket of substantially rectangular shape, welded to all around, inside which are arranged vertical partitions, generally parallel to each other7 substantially perpendicular to the plane of the walls of the pocket1 in order to prevent the latter from spreading; These mattresses have the disadvantage of being relatively fragile at level of attachment of the partitions on the walls: in fact, the result of the pressure force, of the liquid exerted on the wall of the pocket, puts the latter under very high stress because of the tension multiplier effect created by The dividers; which invariably causes a rupture in the vicinity of the weld of the wall and of the partition which is a more fragile area; it is the same phenomenon as that of the breaking of overly stretched electric targets which are covered with frost the weight of frost which causes a multiplier effect of the cable tension force which is all the more important as the deflection is weak ; this state of fragility makes it necessary to put the mattress in a retention tank surrounded by a tube inflated with air or with foam, in order to overcome this drawback; this retention tank undoubtedly constitutes an additional cost, and discomfort for the patient when his bedsores come into contact with this zone bordering on the partitions, which are subjected to a tensile force by the walls of the pocket, when the mattress is loaded , also tend to elongate by creep and the mattress tends to round instead of remaining flat the partitions can cause a roll effect, allowing the upper and lower walls to move laterally, which is uncomfortable for the Patents have been filed to make mattresses from a flat sheet on which is fixed along lines, at regular intervals a film forming a cylindrical groove between two successive fixing lines: this design is similar to that of cartons corrugated having only one support wall of the corrugated part and which are used for wedging objects in the boxes; this mattress design has the major drawback of not being able to properly close in a sealed manner at the ends of the grooves; in any case its realization is very storytelling. The object of the invention is to provide simple and economical solutions to all these problems.

Fig.1 shows the mattress according to the invention whose pocket is welded traditional lean.

Fig.2 shows the same mattress after pleating and fixing the pleats at their ends.

Figs. 3, Fig. 4, Fig. 5 show a detail of the three main steps of a manual pleating method.

Fig.6 shows the mattress according to the invention, deployed is cut in its middle perpendicular to the folds to show how the walls support each other and relieve the welds from any effort.

Fig.7 shows a mattress according to the invention, provided with its cover and handles.

Fig.8 shows an mattress according to the invention in exploded view comprising a cover and in place in a frame forming a retention tank in the event of liquid leakage.

Fig.9 schematically shows a continuous method of manufacturing the mattress according to the invention.

The invention consists in making a sealed pocket (4) Fig.i formed by two sheets which are superimposed to form an upper wall (1) and a lower wall (2) and fixed by a weld on their periphery (3) to delimit a pocket (4) of preferably rectangular shape; the welding of the periphery (3) is in a preferred version of the invention interrupted to constitute an opening (5) allowing the filling of the pocket (4) and which is then closed by known means; the partitions are removed and the upper (1) and lower (2) walls are welded together directly, along weld lines (6) parallel to each other, preferably parallel to one of the sides (7), and substantially equidistant between them n- stance "L"; they delimit cavities (10) inside the pocket (4) Fig.6. These weld lines (6) Fig.1 are not continuous from one edge (8) to another (9) to allow communication of the cavities with each other; in a preferred version of the invention, they are interrupted in the vicinity of the edges (8) and (9) of the pocket (4) defined by the weld delimiting the periphery (3) of the pocket (4).

This manufacturing technique that we have just described is practically identical to that of manufacturing traditional air mattresses, perfectly known, simple and economical, reliable. The heart of the invention lies in the fact that, once the pocket (4) is produced as we have described, it is folded by forming asymmetrical folds (11) Fig.2 lying from the lines of welds (6) Fig.i parallel connecting the walls of the pocket (4) these folds (11) Fig.Z can 4tre all made in the same direction or in an alternating direction without affecting the efficiency of the process, then these folds (11) are fixed at their ends (12) preferably outside the perimeter weld (3) of the pocket (4), so as not to weaken the tightness of the pocket (4); the folds ('it) thus produced are free to deploy in their middle, while the fixing, folds (11) at their ends (12), brings the weld lines closer together
(6) Fig. 'i from each other.When inflating an air mattress which does not have folds each cavity located between two weld lines (6) Fig.1 tends to take the form of a cylinder in areas sufficiently distant from the ends ; the weld lines (6) approach each other and their initial distance "L" from the final distance "D" is in a ratio of the length of a semicircle Ltl to its diameter "D" or "L / D" equal to the constant "PI / 2'1; but one then obtains tubes located side by side forming a corrugated surface not suitable for an anti-decubitus mattress; if one seeks to limit the ripple effect, for example, by inflating the mattress less at this time, the weld lines (6) deviate, the "L / D" ratio becomes less than "PI / 2" and the thickness of the mattress decreases due, in particular, to increasing the support surface of the pocket (4); so that when the load is not uniformly distributed over the mattress7 the upper (1) and lower (2) walls touch each other in the area supporting the load and there is no more lift; the loss of volume, linked to the crushing of the mattress in the loaded area, is compensated by the swelling of the unloaded areas which tend to find the wavy shape observed when the inflation was normal.

The pleating previously described in Fig.2 makes it possible to bring the weld lines (6) Fig.1 together so that their distance "D" Fig.6 is such that, "L" Fig.1 being the initial distance between the lines solder (6), the "L / D" ratio is maintained in the vicinity of "PIS2" to within 10 percent more or less, but preferably greater than ItPl / 2t. In these conditions, when the pocket (4) Fig. 6 is partially inflated, the upper (1) and lower (2) walls tend to take a substantially rectangular shape outside the zone of influence of the fold fixing zone. ends (12) and the zones (13) of the upper wall (1), on the one hand, and (14) of the lower wall (2) on the other hand, of the pocket (4), located respectively from on either side of the weld lines (6) bear one on the other and balance each other under pressure, so that the weld line (6) is practically more in demand; as the spacing "D" of the weld lines (6) is limited, for the same amount of water, the mattress retains a thickness (15) greater than if the spacing of the weld lines (6) was not not limited since the bearing surface does not increase. As we said previously the weld lines (6) Fig.1 are not continuous to allow the passage of the liquid between the cavities (10) Fig.6 determined by these lines (6) it is possible to limit by flow the flow rate through these passages by reducing the size; in particular in a preferred version of the invention, these passages are situated at the end (12) of the weld lines (6) which do not come into contact with the perimeter weld line (3) of the pocket (4); they have the advantage that they are limited in flow by the asymmetrical fold (11) which is not deployed in the vicinity of the end (it) which plates the walls () and (2) of the pocket (4) between them and this all the more firmly as the area is stressed by a load which causes tensions at the ends (12) of the folds (11); So much so that if one zone is loaded more than another the transfer of liquid which tends to escape from the cavity (10) concerned in order to reinflate the cavities (10) less charged is slowed down; which increases the time the mattress is crushed in this area and gives the patient time to settle in to distribute the load. This procedure allows the mattress to be less inflated to increase the contact surface with the patient's body. without increasing the risk that the walls () and (2) of the pocket (4) come into contact. To obtain the same level of performance from the point of view of crushing under poorly distributed load, the traditional anti-decubitus mattress, comprising partitions, must be more inflated to limit the transfer of water since it is impossible to do effective rolling of the passages between the cavities, which leads to a smaller contact surface with the patient's body, therefore greater pressure on the latter and it is also heavier to handle.

The mattress being welded as before, the formation of the folds Fig. 3 is ensured by means of perforations (16) located on a line perpendicular to the weld lines (6), outside the sealing zone created on the periphery ( 3), and distributed on either side of the line corresponding to a weld line (6); the folds are made by hand on the fold fastening electrode which includes pins (17) on which thread the perforated walls with holes (6) Fig.4 to form the fold (11) Fig.5 ; a first weld ensures their fixing; The final fixing of the folds can be made, preferably, by adding a strip (18) Fig.2 of plastic material of composition compatible with that of the mattress and which is welded on the end ( 12) folds (11); there may be a single strip (18) on a single side or one on each side; the advantage of proceeding from this baleen is to transfer the tensile force exerted on the folds (11) by the pressure of the liquid, which would tend to open the welds in a tensile force supported almost entirely by the fixing strip ( 18); it is important that this strip (18) 1 to play its rtle well, be little subject to creep.

This strip (18) can also be used to make handles (19) Fig. 7 on either side of the mattress to facilitate handling; after use these handles (19)
Fig.8 are retracted by folding under the mattress.

Another way of making the folds is to start with two rolls of film (20) and (2) Fig. 9 of film, to make step by step the peripheral sealing weld (3) and the weld lines (6 ) of each mattress at regular intervals, so that the weld lines (6) are in the direction of travel (22) of the film strips (20) and (21); the assembly is then pleated continuously using ramps (24) which first cause an undulation (25) of the strip, lengthwise, which is gradually flattened to give the asymmetrical folds folded (it ) which can Other then fixed by welding (12) step by step at the same pace as the first welding in one or two stages depending on whether the consolidation film (18) is added from the first stage or during a stage additional; it remains to make the appropriate cuts described above to make for example handles (9) and open the filling channel (5) located in the joint plane as described above. The advantage of such a process is that it can be fully automated. These two descriptions of the manufacturing do not constitute an exhaustive list of the manufacturing of the mattress.

As the surface of the mattress practically does not vary according to the inflation, it is advantageous to place it in a cover (Z3) Fig.7 adjusted to the shape of the mattress; this cover (Z3) allows, when the mattress is loaded on a small area to increase the area interested directly by the load and thus further limit water transfers; and this also allows the patient to lean on a surface without roughness while the welds of the partitions in the traditional mattress could come into contact with the patient's body; this cover (23) which is permanently in place allows the filling duct (5) to pass and participates in the production of the handles (19).

In some countries the legislation requires the presence of a retention tank capable of retaining water in the event of a leak; one solution to this problem consists in cutting a film (26) Fig.8 substantially in the shape of the support surface of the mattress and in fixing it by welding7 around its periphery (27) another film (28), having the same external shape that the film (2b) l but whose center (29) is cut to form only a frame (31); the mattress (30) is placed between the frame <3.1) which serves as a rim and the bottom (26), which has substantially its shape, on which it rests: in the event of a leak, water is retained by the frame (31 ) whose width is sufficient to reach at least the top of the mattress (30>.

Claims (7)

Claims -1-Anti-decubitus mattress, formed of two sheets () and (2) welded between Ilns along their periphery (3) to constitute the seal and comprising welding lines (6) delimiting cavities (10) communicating and parallel, characterized in that it is pleated with asymmetrical folds (11) parallel to the weld lines (6), fixed at their ends (12) but free to deploy in their middle when the mattress is inflated, making it possible to keep the weld lines (6) close together, so that the walls (13) and (14) can come to bear respectively on each other and give the cavities (10) a shape of substantially rectangular section, in order to obtain a substantially flat mattress surface. 2-Anti-decubitus mattress, according to the preceding claim, characterized in that the ratio "L / D" is equal to the constant "PI / 2" to within 10 percent. 3-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the zone (2) de'fixation of the folds (11) is situated outside the sealing periphery (3). 4-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the fixing of the folds (11) is reinforced by at least one strip (18). 5-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the cavities (10) communicate at their ends and the folds (11) are made at the weld lines (6), so as to keep the walls (1) and (2) pressed against each other and strongly laminate the water flow going from one cavity (10) to the other, to prevent too rapid crushing of the mattress under the action of a point load, and allow to decrease the inflation of the mattress and increase the support surface on the patient's body. h-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the folds are formed by means of perforation (16) made outside the periphery (3) which are threaded on pins ( 17) integral with the welding electrode. 7-Anti-decubitus mattress, according to any one of claims 1 to 5, characterized in that the mattresses are produced from two reels of film (20) and (21) forming the upper (4) and lower walls. (2) the folds being formed continuously using a conformator (24) which forms an undulation (25) oriented in the direction of travel of the films (22) which is progressively deformed to obtain the asymmetrical folds (11) which are then fixed to the ends (12) separating two successive mattresses during manufacture. 8-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the mattress is covered with a cover (23) giving a smooth appearance to the surface of the mattress.  9- & anti-escarres7 telas according to any one of the preceding claims, characterized in that the mattress has handles (19) allowing its manipulation. 10-Anti-decubitus mattress, according to any one of the preceding claims, characterized in that the mattress is, 'introduced between a bottom (26) in flexible film and a frame (31) in flexible film which covers the edges of the mattress leaving the free center, in order to constitute a retention tank.