INFLATABLE AIR MATTRESS

Abstract: Disclosed is a one-piece inflated air mattress (1) that can be used as such or laid over a hospital bed mattress. Its body (3) is formed of a series of transverse parallel pillow-like air tunnels (5) connected at their ends with a pair of lengthwise distribution channels (7). The body (3) has an inlet end (9), to which an air pressure source (17) is connected, and a terminal end (11); the distribution channels (7) running between the two ends (9, 11) and tapering from one end to the other, being wider at the inlet end (9) than at the terminal end (11). An open-ended plenum conduit (15), located at the inlet end (9) of the body (3), communicates at its ends respectively with said distribution channels (7).

Description: The present invention relates to an inflatable air mattress used to improve the comfort of patients that are immobilized over long periods of time. The mattress of the invention can be used as such or be placed over the mattress of a conventional hospital bed and it is independent from it. For this type of patients, it is recommended to provide a mattress which is quite flexible throughout its length to prevent the creation of pressure points on parts of the patient's body that support its weight. These pressure points tend to cause occlusion of blood capillaries on the surface of the skin resulting in the development of body sores or skin rashes. The patent literature is replete with suggestions of mattress constructions intended to prevent this problem. While all of them seem to be based on the use of air inflatable mattresses, a very large number are more specifically adapting the principle of creating a ripple effect on the surface of the mattress, and consequently on the patient's body, to activate blood circulation. However, the known mattresses are quite complex in structure because of the presence of individual air circuits that are separately and alternatively supplied with pressure air and because of the complicated mechanical and electrical control system that is required to operate the mattress properly. These mattresses are consequently extremely costly. Patents known to the present applicants and addressing this subject are as follows: An object of the present invention is to provide an inflatable air mattress in which air can be moved throughout its inner cavity without hindrance, in the manner of communicating vases, so that a pressure created by a particular portion of the patient's body is immediately transmitted to the complete air mass, thereby avoiding the creation of pressure spots. Another object is to provide a mattress having transverse air tunnel-like pillows supplied, at their ends, by lateral air distribution channels of which the cross-section decreases from the air inlet end to the terminal end of the mattress thereby providing uniform air pressure in all pillows regardless of their position with respect to the inlet end. According to the invention and starting from the DE-A-3 320 771, there is provided an inflatable air mattress in the form of a one-piece elongate body made of flexible plastics material or air-retentative fabric, said mattress being of the type comprising, in inflated condition: an air inlet end and a terminal end away from said inlet end; a pair of air distribution channels located alongside of said body and extending over essentially the full length thereof from said inlet end to said terminal end; a plurality of elongated parallel pillow-like straight air tunnels extending transversely of said body and disposed adjacent one another along essentially the full length of said body, each of said air tunnels having opposite ends in communication with said distribution channels respectively in order to be supplied with inflation air from said channels; an open-ended transverse plenum conduit at said inlet end, said conduit being in communication with said distribution channels, whereby said channels, said air tunnels and said plenum conduit communicate with one another; and air pressure supplying means operatively connected to said transverse plenum conduit to supply said conduit, said channels and said tunnels with inflation air, characterized in that: said distribution channels taper from said air inlet end to said terminal end, each channel having a cross-section that is larger at said inlet end than at said terminal end; and each air tunnel is integrally formed with a small air pocket at each end, said pocket extending over and covering the adjacent distribution channel so as to increase the length of said air tunnel and to make it extend over at least the width of the rest of the mattress. The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a mattress according to the invention. Figure 2 is a top plan view of the mattress of Figure 1; Figure 3 is a perspective exploded view of part of the mattress; the upper section being shown in three different steps of its formation; Figure 4 is a longitudinal side elevation view of the mattress; and Figure 5 is a cross-sectional view taken about halfway along the length of the mattress. The illustrated inflatable air mattress 1 is in the form of a one-piece elongated body 3 entirely made of flexible plastic material, preferably vinyl or an urethane coated nylon such as DERMOFLEX of an air-retentative fabric. The body 3 comprises, in inflated condition, a series of elongated parallel pillow-like straight air tunnels 5 that extend transversely of the body 1 and are disposed adjacent one another along essentially the full length of the body. In properly inflated condition, the tunnels 5 touch one another as best shown in Fig. 4. All obviously are of equal size and of constant cross-section. Tunnels 5 all communicate with air distribution channels 7 in order to be supplied with inflation air. Channels 7 extend the full length of the body 1, tapering from the air inlet end 9 of the body 3 to its terminal end 11, that is, having a greater cross-section at the inlet end 9 than at its terminal end 11, as seen in Figures 2 and 3. With the tunnels 5 opening directly into both channels 7, tapering of the latter ensures constant pressure throughout the mattress body 3 under the communicating vessels principle. Therefore, the above described structure allows all air pillows or tunnels 5 to be inflated at the same pressure regardless of their location with respect to the inlet end 9. Due to the excellent pressure distribution obtained with the tapering channels 7, the pressure output of the air supply unit, in this case the compressor 17, to keep the air tunnels 5 properly inflated to support a patient's body may be as low as 13,75 cm (5.5") of water as compared to 20 cm (8") to 35 cm (14") in conventional systems. The air distribution channels 7 are interconnected, at the inlet end 9, by a transverse plenum conduit 15. In this manner, the conduit 15, the channels 7 and the air tunnels 5 all communicate with one another to form a series of closed air circulation circuits. The plenum conduit 15 is supplied with air under pressure by a pressure-adjustable compressor unit 17 connected to the plenum conduit 15 by a flexible hose 19. With this arrangement, the plenum conduit is in direct communication with the compressor 17 and no valve assembly and/or cyclic switches or the like need be used thereby appreciably reducing the total cost of the mattress assembly, as aforesaid. It will be appreciated that the hose 19 may be connected to the first one of the air tunnels 5 which then replaces the plenum conduit 15. The result would be the same since the first tunnel 5 interconnects the two channels 7. The same reasoning applies at the terminal end 11 of the mattress where a plenum conduit 21 is provided to join the relevant ends of the channels 7. Again, the last tunnel 5, at the terminal end 11, may be used as the plenum conduit. As best shown in Figure 2, because of the tapering or narrowing down of the air distribution channels 7 and to keep the mattress 1 of constant width, the air tunnels may be integrally formed with small air pockets 22 (see Fig. 5) extending over and projecting laterally beyond the channels 7. An exception may be in the first tunnel 5 or so adjacent to the inlet end 9 where the tunnels extend over but not beyond the channels. Referring now to Figures 2 and 3, the mattress body 3 may be made up of preformed top and bottom parts 23 and 25. The top part 23 is obtained from a plastic sheet blank 27 having a U-shaped slots 29 formed along opposite lateral edges. To obtain a tunnel 5, the sheet 27 is folded up along an axis 30 between two successive slots 29 until the tunnel 5 is obtained, having essentially the shape of an inverted U (see fig. 4), in cross-section, with a pair of straight spaced legs 31 and a dome-shaped bight 33. With all the tunnels 5 thus shaped, the opposed longitudinal edges of the blank 27 are then first bent down and then outwardly to form weld flanges 35. Next, the so far shaped top part 23 is applied over the lower part 25 with the lower edges of the spaced legs 31 sitting squarely over the central portion 36 (between the air distribution channels 7) and welded thereto along weld lines 37, all of equal length across the mattress body 3. The central portion 36 then serves as flat bottoms for the tunnels 5. The unconnected edges of the ends of the tunnels 5 are then brought together, as shown by the horizontal arrows in fig. 3, and are welded to close the tunnels 5 which then communicate with the channels 7 and the plenum conduits 15 and 21. The two sheet parts 25, 27, are finally welded along their weld flanges 35, 35′. As mentioned above, the weld lines 37 across the central portion 36 of the bottom part 25 are all of equal length. Referring to fig. 2, in order then for the channels 7 to taper from the inlet end 15 to the terminal end 11, it is necessary that the lateral edges of the top and bottom parts 23, 25, more precisely the weld flanges 35, 35′, taper in between the ends 9 and 11, as shown. In order to avoid contamination of the mattress by the patient, an air permeable and water imprevious sheet 37 (fig. 2) is applied over the mattress 1. The lower surface of sheet 37 consists of an air permeable hydrophobic urethane coating. The upper surface is made of a permeable woven textile material. Air necessary to reduce or prevent maceration comes from a plurality of bleed holes 39 (fig. 1) through the dome-shaped bights 33 of the tunnels 5. Finally, and as illustrated in Figs. 4 and 5, contoured end flaps 41, 43, are provided at the inlet end 9 and at the terminal end 11. They project down from the mattress bottom part 25 and extend across the ends 9, 11, as well as along a portion of the body 3 so as to tuck in the body 3 around the ends of a hospital bed mattress to firmly hold it in position thereon.

Claims: 1. An inflatable air mattress in the form of a one-piece elongated body (3) made of flexible plastics material or air-retentative fabric, said mattress being of the type comprising, in inflated condition: an air inlet end (9) and a terminal end (11) away from said inlet end; a pair of air distribution channels (7) located alongside of said body (3) and extending over essentially the full length thereof from said inlet end (9) to said terminal end (11); a plurality of elongated parallel pillow-like straight air tunnels (5) extending transversely of said body (3) and disposed adjacent one another along essentially the full length of said body, each of said air tunnels (5) having opposite ends in communication with said distribution channels (7) respectively in order to be supplied with inflation air from said channels (7); an open-ended transverse plenum conduit (15) at said inlet end (9), said conduit (15) being in communication with said distribution channels (7), whereby said channels (7), said air tunnels (5) and said plenum conduit (15) communicate with one another; and air pressure supplying means (17) operatively connected to said transverse plenum conduit (15) to supply said conduit (15), said channels (7) and said tunnels (5) with inflation air, characterized in that: said distribution channels (7) taper from said air inlet end (9) to said terminal end (11), each channel (7) having a cross-section that is larger at said inlet end than at said terminal end; and each air tunnel (5) is integrally formed with a small air pocket (22) at each end, said pocket extending over and covering the adjacent distribution channel (7) so as to increase the length of said air tunnel and to make it extend over at least the width of the rest of the mattress. 2. An air mattress as claimed in Claim 1, characterised in that said air pressure supplying means comprises: a pressure-adjustable compressor assembly (17); and an air inlet conduit (19) having one end connected to said compressor assembly (17) and another end connected to said plenum conduit (15), said air inlet conduit (19) being devoid of any air-flow control device. 3. An air mattress as claimed in Claim 1 or 2, characterised in that said plenum conduit (15) is the first one of said air tunnels (5) at said inlet end (9) of said body. 4. An air mattress as claimed in any of Claims 1 to 3, characterised in that said air tunnels (5) have a constant cross-section and are of equal size. 5. an air mattress as claimed in any preceding claim characterised in that each air tunnel (5) is, over the major part of its length, of inverted U-shaped cross-section, and has a pair of straight side portions (31), a dome-shaped top portion (33) and a flat bottom. 6. An air mattress as claimed in Claim 5, characterised in that said dome-shaped top portion (33) is perforated with air bleed holes (39). 7. An air mattress as claimed in any preceding claim, characterised in that said body (3) is made up of top and bottom preformed parts (23, 25) heat-welded along common outer edges thereof (35, 35′) and along the lower edges of said side portions (31) of said air tunnels (5). 8. An air mattress as claimed in any preceding claim, further comprising contoured end flaps (41, 43) at said inlet end (9) and at said terminal end (11), said flaps projecting down from said body (3) at the ends thereof and along a portion of the sides of said body for tucking in said body around the ends of a bed mattress. 9. An air mattress as claimed in any preceding claim characterised in that said flexible plastics material is an urethane coated nylon. 10. An air mattress as claimed in any of claims 1 to 8, characterised in that said flexible plastics material is a vinyl coated nylon.

Inventors: CHAMBERLAND, PAUL
Applicants: S.S.I. MEDICAL SERVICES OF CANADA INC.
Application year: 1989
Main classification: A61G7
IPC codes: A47C27, A61G7