WO2013164687A1

WO2013164687A1 - Pneumatic mattress

Info

Publication number: WO2013164687A1
Application number: PCT/IB2013/001004
Authority: WO
Inventors: Martin Toms; Brian Frank Pile; Ian Malcolm Ryall
Original assignee: Linet Spol. S.R.O.
Priority date: 2012-05-03
Filing date: 2013-04-29
Publication date: 2013-11-07
Also published as: GB201207839D0

Abstract

Pneumatic mattress having a plurality of pneumatic cells has an upper layer having a plurality of pneumatic cells, including a head- and-torso group, and a seat- and-upper-leg group of cells, having a bend region between these groups. The mattress also having a lower layer having a head-and-torso portion and a seat-and- upper-leg portion with a bend region between the portions. The upper and lower layers being adapted for the upper layer to slide on the lower layer at the head-and- torso section, when the backrest of the mattress is raised, bending the mattress at the bend region. The upper layer is restrained from sliding over the lower layer at the seat-and-upper- leg region, allowing the head-and-torso group of cells can slide up the lower layer, when the back rest of the bed is raised.

Description

PNEUMATIC MATTRESS

The present invention relates to a pneumatic mattress. We have filed a number of patent applications in respect of a type of pneumatic mattress, which has a plurality of pneumatic cells so connected that sets of them can be selectively and cyclically pressurised and exhausted - or inflated and deflated - in sequence to support a user, normally a patient liable to suffer or actually suffering from pressure sores. Cycling the mattress simulates movement that a patient would make if fit and healthy so as to avoid supporting his/her weight in the same place all the time.

In certain markets constant pressure pneumatic mattresses are preferred. In such a mattress the pneumatic cells are all constantly inflated.

Pneumatic mattresses are often formed with two layers of cells, with superimposed pairs of cells being connected together, whereby bending of the mattress as in raising of a backrest of a bed on which the mattress is in use is liable to be accompanied by compression of the cells on the top surface of the mattress. This is uncomfortable for the patient as explained in more detail below.

The object of the present invention is to provide an improved pneumatic mattress According to the invention there is provided a pneumatic mattress having a head-and-torso part and a seat-and-lower-leg part for a bed having a raisable back rest for patient sitting up, the mattress comprising:

• an upper layer having a plurality of pneumatic cells including:

• a head-and-torso group of cells and

· a seat-and-upper-leg group of cells,

the cells being so formed and the groups of cells being so connected as to provide: • a bend region across the upper layer at which the upper layer bends, when the back rest of the bed is raised;

• a lower layer having:

• a head-and-torso lower layer portion,

• a seat-and-upper-leg lower layer portion and

• a bend region beneath the bend region in the upper layer,

the upper and lower layers being adapted for the upper layer to slide on the lower layer at the head-and-torso part of the mattress, when the back rest of the bed is raised; and

• means for restraining the seat-and-upper-leg group of cells of the upper layer from sliding on the lower layer, whereby the head-and-torso group of cells can slide up the lower layer, when the back rest of the bed is raised.

This arrangement provides that the two groups of cells are not compressed towards each other as they bend. In turn, this mitigates against a patient's skin being sheared on the mattress as the back rest of the bed is raised.

The head-and-torso and the seat-and-upper-leg groups of cells can be separate groups fastened together for bending or they can be a singly formed set of cells adapted to bend between the groups either by provision of bend formations in longitudinally extending cells or by arranging for two laterally extending cells to be in abutment at their bend region.

In the bend region of the preferred embodiment, some cells extend

longitudinally and some transversely. End ones of central transverse cells are fastened together and abut at the bend region and edge cells extend longitudinally in both directions with respect to the bend region, with bend formations in the edge cells.

The lower layer can be a foam sheet which is continuous between the portions, within a cover and able to bend at its bend region, Alternatively as in the preferred embodiment, the portions are separate and connected together by means of their cover. It is by making the cover of low friction material, preferably of polyurethane coated nylon fabric, that the layers are able to slide the one on the other at the head- and-torso group of cells. The means for restraining the layers at their seat and lower leg group/portion can be provided intermediate edges of the mattress, as by hook and loop fastening means or indeed by means of tethers provided at the inner edges of edge ones of longitudinally extending cells. In the preferred embodiment, tethers are provided at the outer edges of longitudinal cells. The tethers can be straps, or other tension restraining members, secured between the layers in the extent of the seat-and-upper- leg cell group and the lower layer. Again in the preferred embodiment, two tethering straps are provided, secured to respective edge ones of longitudinal cells at their bend formations and to the lower layer in its head-and-torso portion. Securement in this way does allow some restrained movement of the seat-and-upper-leg group of cells over the lower layer. However the primary result of the restraint - or lack of it throughout the head-and-torso part of the mattress - is that the difference in height of the bend regions does not act to compress the head-and-torso cells, rather allowing them to ride up the lower layer. Additional restraining means can be provided. In the preferred embodiment, lower leg cells are tethered to the lower layer. Conveniently this is at the foot of the mattress, via tethering of heel cells to the lower layer portion.

Conveniently again, the upper and lower layers are together contained with a cover, whose looseness accommodates the limited movement of the layers just described, whilst not allowing substantial separation of the mattress layers, such as the possibility that there would be to bend the head-and-torso cells away from the lower layer in the absence of the cover. This is preferably formed as a semi-permeable cover, which allows moisture to permeate the cover and to be carried away by air flow within the cover. Between the cells and the cover, a replaceable open weave or gauze layer of non- woven material is preferably provided.

Whereas conventional constant pressure pneumatic mattress cells are provided with perforations for spilling air to allow the cells to deform to a patient's body shape, as disclosed in our application of even date, we prefer to provide means for flowing air to spaces between at least some of the individual cells beneath the cover.

To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a mattres s according to the invention with the top sheet of a mattress cover removed;

Figure 2 is a longitudinal, central-cross-sectional, side view of the mattress of Figure 1 with a limited number of bed parts shown;

Figure 3 is a side view of the mattress of Figure 1 viewed from inside the side edge portions of the mattress cover;

Figure 4 is a view similar to Figure 3 with the back-rest raised;

Figure 5 is a transverse cross-sectio al end view of the mattress of Figure 1 on the line V-V in Figure 1; and

Figure 6 is another transverse cros s -sectional end view of the mattress of Figure 1 , this on the line VI- VI in Figure 1.

Referring to the drawings, a pneumatic mattress 1 is includes of a single cell deep layer 2 of transverse pneumatic cells 3. These are provided as four groups, a head-and-torso group 31, a seat-and-upper-leg group 32, a lower leg group 33, and a heel group 34. The groups are pneumatically separate from each other, in that all the cells within each group are pneumatically interconnected and separately supplied with inflation air, by a non-shown pump, which performs no function in the invention save providing pumped air. The exception from the pneumatic interconnection is in the heel group which has a manual control for inflating either, both or neither of the two super imposed pairs of heel group cells, for extending the mattress from a shorter to a longer length or vice versa. The cells within the groups are integral in that they are formed from the same two layers of polymeric material welded together to provide the cells and their pneumatic connection. The groups are distinct and detachably connected together as follows:

• group 31 being clipped with pop fasteners 35 to group 32;

• group 32 being clipped with pop fasteners 35 to group 33; and • group 33 being strapped to group 34 as explained in more detail below.

Two out of three of the head cells 4 in the group 31 and the cells of the group 33 are full width, with the other transverse cells being shorter. The heel cells are some 10% shorter. Along the mattress, across the ends of the other shorter cells, i.e.

in the groups 31, 32, two sides cells 5 extend. These are connected in two ways to the neighbouring cells. Firstly, air connectors 51 on the underside of certain cells in the groups 31,32,33 are passed through dumbbell slots 52 in margins 53 of the side cells. Secondly, loop connections 54 are made between individual cells in the groups 31, 32, 33 and corresponding apertures 56 in the margins 53. These are connected at 57 to the head cell adjoining the torso cells, at 58 to the junction between the torso cells and the seat cells and at 59 to the lower leg cell adjacent the torso group. The side cells are necked at 58, providing in conjunction with the junction of the cells 31,32 a bend region 36 for the upper layer.

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Here, in accordance with the present invention, the pneumatic cells as a whole are connected by tethers 6 passing through apertures 60 in outer margins of the side cells to'a lower layer 7 of the mattress, provided as three portions 71, 72, 73 beneath the cell groups 31, 32, 33.

The three portions are of foam slab, enclosed in a cover 74. This is continuous from end to end of the lower layer, with the top and bottom sheets of the cover being stitched together at the joints 75, 76 between the respective portions 71, 72 and 72, 73. Thus the portions can be articulated with respect to each other at the joints, in other words the joints and stitching provide bend regions in the lower layer. The fabric of the lower portion cover has a low friction layer, conveniently of

polyurethane coating on nylon fabric, whereby the upper layer can slide on the lower layer even if a patient is lain on the bed. The tethers 6 have toggles 69 engaging the cell margins at the apertures 60 and are stitched into a seam 77 running along the sides of the head-and-torso portion 71 of the lower layer. The strap normally adopts an angle of between 40° and 50° to the general extent of the layers when the back rest of the bed is not raised and the pneumatics cells are not compressed by the patient's weight. It is envisaged that the angle could readily be between 30° and 60°. When a back rest of the bed is raised, the lower layer is caused to bend about its bend region 75 and the upper layer is caused to bend about the bend region 36 represented by the joint between the upper groups of cells 31, 32 and the necking tether point 58. Without slippage of the upper layer of cells on the lower layer, the cells of the upper layer at the bend region 36 would tend to be compressed with the result that a patient laid on the mattress, albeit with the interposition of a mattress cover 9 and the bedding not shown, would experience drawing of the skin along his/her back towards his legs and along his legs towards his back. This is uncomfortable and potentially damaging to the skin. It is known as and referred to here as the "shear effect".

On the one hand, the tethers and indeed the patient's weight in spreading the cells' contact and frictional grip with the lower layer act to prevent major sliding movement of the torso and upper leg group 32 of cells over the corresponding lower layer portion 72. They prevent uncontrolled slippage down the bed. In other words, the tethers do not in their action on the cell group 32 relieve any shear effect. On the other hand, they do not cause it either in that the cell group 32 is free to remain the same length and not move in shear under the seat-and-upper-leg of the patient.

On the other hand, the tethers do allow minor movement of the cell group 32 in that as the head-and-torso lower layer is raised, articulating about its bend region 75, the tether tends to be slackened due to its attachment to the seam 77 describing an arc.

As pointed out above, it will be appreciated that if the head-and-torso group 31 of cells were attached to the head-and-torso lower layer they would be pushed towards the bend region 36 resulting in the shear effect developing. However, the group 31 is free to move up the lower portion 71.

Whilst the tethers give the head-and-torso cells freedom to move, they do not limit the movement of the seat-and-upper leg cells when the back rest is raised. This movement is partially restrained by the patient's weight. It is also restrained by the cover 9 which is comprised of:

• a lower sheet 91 with an up-turned edge 97,

• a top sheet 92 with a down turned edge 93,

• a sliding clasp fastener 94 jointing the two edges,

• a skirt 95 from the top sheet covering the fastener,

• an open-weave, non-woven layer 96 separate from the top sheet and clipped to opposite end one of the cells.

The top sheet is or moisture vapour permeable breathable fabric through which moisture vapour from a patient can pass inside the cover.

The cover is loose, i.e. not so tight that the head-and-torso group of cells cannot move up the lower portion. The cover does however keep the layers of the mattress in loosely restrained contact.

In addition to the head-and-torso and seat-and-upper-leg portion of the mattress, it has the lower leg transverse cell group 33 and the lower leg lower portion 73 with kneed bend regions 37, 76. At the centre 101 of the foot end of the portion 73, a loop 102 is stitched into the seam of the lower portion fabric. This is engaged by a hook 103 connected by its own loop 104 to the lower sheet of the mattress cover. The stitching of the loop 104 attaches an external strap 105 for fastening to the frame 106 of a bed (only partially shown). Two super-imposed pairs of "heel sore" cells 111 are provided beyond the foot end of the lower leg cells. This group of four cells is held together by straps 1 12 at each side of the mattress. They engage in apertures 113 in flaps 1 14 extending from the cells and are retained by toggles 115. The straps pass through eyes 116 on the foot end one of the lower leg cells and through loops 117 in the foot end of the mattress lower portion. The straps hold these parts of the mattress together. They loosely restrain the lower leg cells from sliding over the lower leg portion. This function is enhanced in use by abutment of the heel sore cells with a foot board 118 of the bed. The arrangement just described restrains the seat-and-upper-leg and lower-leg groups of cells from sliding on their lower layer portions. Thus the shear effect mitigation provided by the mattress is achieved by loose restraint of the layers of the mattress from moving with respect to each other, except at the head-and-torso cells where slippage movement can occur so that the distance along the surface of the cells in contact with the top sheet of the cover remains substantially the same the back rest is raised or not. This is in marked contrast to a two cell layer pneumatic mattress in which the top cells are connected to the bottom cells and compression of the top cells occurs where they are bent o raising of the bed's back rest.

The invention is not intended to be restricted to the details of the above- described embodiment. For instance, since a greater proportion of the patient's weight is taken by the seat group of cells when the back rest is raised, a control system of the bed can be adapted to raise the air pressure in these cells, when the back is raised. The side cells can be raised to the same increased pressure. In accordance with the invention of our other application of even date, air supply manifolds 8 extend at both sides of the mattress between the side cells 5 and the cell groups 32,33. They are formed in the same manner as that the cells, that is of two welded layers of polymer sheet. They are clipped to the cells by the loop connectors 54. In their sheets 81 facing inwards of the mattress, they are provided with perforations 82, at positions corresponding to spaces 83 between the upper portions 84 of the cells.

With the cells inflated, the top cover evenly laid on the cells and air being pumped to the manifolds 8, there is air flow inwards between the individual ones of the torso and upper leg cells, in the spaces 83. Insofar as this flow is from both ends of the spaces, it leaves them longitudinally of the mattress via the open weave layer 96 and any local lifting that there may be of this layer from the tops of the cells. In use with a patient laid on the mattress, the top sheet and the open weave layer are locally pressed onto the cells by the patient's body. The body's weight is supported by the pressure in the cells times the surface area of the cells flattened to support the body. The pressure is set for the body weight such that there is some space 83 remaining between individual cells. Air flows here, drawing away with it moisture permeating through the top sheet of the cover and passing through the open- weave layer to the spaces. In certain areas, such as under the patient's back, some flow will occur through the open weave layer.

Claims

CLAIMS:

1. A pneumatic mattress having a head-and-torso part and a seat-and-lower-leg part for a bed having a raisable back rest for patient sitting up, the mattress comprising:

• an upper layer having a plurality of pneumatic cells including:

• a head-and-torso group of cells and

• a seat-and-upper-leg group of cells,

the cells being so formed and the groups of cells being so connected as to provide:

• a bend region across the upper layer at which the upper layer bends, when the back rest of the bed is raised;

• a lower layer having:

• a head-and-torso lower layer portion,

• a seat-and-upper-leg lower layer portion and

• a bend region beneath the bend region in the upper layer,

2. A pneumatic mattress as claimed in claim 1 , wherein the head-and-torso and the seat-and-upper-leg groups of cells are separate groups fastened together for bending.

3. A pneumatic mattress as claimed in claim 1, wherein the head-and-torso and the seat-and-upper-leg groups are a singly formed set of cells adapted to bend between the groups either by provision of bend formations in longitudinally extending cells or by arranging for two laterally extending cells to be in abutment at their bend region.

4. A pneumatic mattress as claimed in any preceding claim, wherein in bend region in the upper layer some cells extend longitudinally and some transversely.

5. A pneumatic mattress as claimed in claim 4, wherein central transverse cells are provided together with longitudinal edge cells.

6. A pneumatic mattress as claimed in claim 5, wherein end ones of central transverse cells are fastened together and abut at the bend region and edge cells 2013/164687

11 extend longitudinally in both directions with respect to the bend region, with bend formations in the edge cells.

7. A pneumatic mattress as claimed in any preceding claim, wherein the lower layer is a foam sheet which is continuous between the portions, within a cover and able to bend at its bend region.

8. A pneumatic mattress as claimed in any one of claims 1 -6, wherein the portions of the lower layer are separate and connected together by means of their cover.

9. A pneumatic mattress as claimed in any preceding claim, wherein the upper and lower layers are provided in a cover of a low friction material.

10. A pneumatic mattress as claimed in claim 9, wherein the low friction material is polyurethane coated nylon fabric.

11. A pneumatic mattress as claimed in any preceding claim, wherein the means for restraining the layers at their seat and lower leg group/portion is provided

intermediate edges of the mattress, as by hook and loop fastening means or by means of tethers provided at the inner edges of edge ones of longitudinally extending cells.

12. A pneumatic mattress as claimed in claim 5 or any one of claims 6 to 10 as appendant to claim 5, wherein the means for restraining the layers at their seat and lower leg group/portion is tethers provided at the outer edges of longitudinal cells.

13. A pneumatic mattress as claimed in claim 12, wherein the tethers are straps, or other tension restraining members, secured between the layers in the extent of the seat-and-upper-leg cell group and the lower layer.

14. A pneumatic mattress as claimed in claim 12 or claim 13, wherein two tethering straps are provided, secured to respective edge ones of longitudinal cells at their bend formations and to the lower layer in its head-and-torso portion.

15. A pneumatic mattress as claimed in any one of claims 12 to 14, further including additional restraining means.

16. A pneumatic mattress as claimed in claim 15, wherein the mattress further includes lower leg cells tethered to the lower layer.

17. A pneumatic mattress as claimed in claim 9, wherein the cover is loose such that it accommodates the limited movement of the layers, whilst not allowing substantial separation of the mattress layers.

18. A pneumatic mattress as claimed in claim 17, wherein the cover is formed as a semi-permeable cover. 2013/164687

12

19. A pneumatic mattress as claimed in claim 17 or 18, further including a replaceable open weave or gauze layer of non-woven material between the cover and the cells.

20. A pneumatic mattress as claimed in any preceding claim, further including means for flowing air to spaces between at least some of the individual cells beneath the cover.