MATTRESS

The present invention relates to a mattress suitable for use with a hospital bed, in particular a hospital bed intended to be configured into a variety of positions.

Configurable hospital beds, which are in widespread use, typically have sections which can be raised or lowered to adjust the contour of the bed and thus the patient's position. Such beds allow, for example, a patient to be supported in a lying position, in a sitting position and in many other configurations as required or desired. When such beds are configured into a patient sitting position or in a legs up position, the bed mattress becomes compressed at the junction between the portions of the bed which form a concave zone when viewed from above. This contrasts with the need for the patient's body to extend when sitting or in a legs up position, since the body extends and the mattress compresses. This results in the patient experiencing shear between their body and mattress surface.

Hospital mattresses are also made of a reasonable thickness and firmness to provide good patient comfort and support, which can worsen the problems identified above. Such mattresses can also cause patient discomfort at those parts of the body requiring most support, such as the pelvic area. This discomfort is typically caused by the closing in of the mattress surface around such areas and an increase in pressure and shear.

The present invention seeks to provide an improved mattress.

According to an aspect of the present invention, there is provided a mattress for use with a configurable bed including a first mattress layer provided with a plurality of incisions in a lower surface thereof, said incisions extending in a transverse direction of the mattress.

The incisions allow for the mattress to extend during reconfiguration of the various sections of the bed, improving patient comfort by reducing compression points.

Advantageously, the incisions are of different depths in order to increase the contact area between the patient and the mattress, based on optimum anthropometric data for most patients.

In the preferred embodiment, the mattress includes at least one second incision provided in an upper or intermediate surface of the mattress.

Advantageously, the or each second incision is offset relative to the lower surface incisions in a longitudinal direction of the mattress. This allows the mattress to stretch in a concertina manner, as described below.

The mattress may be provided with one or more V-shaped grooves in the lower surface of the mattress, extending in a transverse direction thereof. The V-shaped grooves act as a hinge, facilitating bending of the mattress in the direction of opening of the grooves.

Preferably, there is provided a second mattress layer overlying the first mattress layer. The second mattress layer is most preferably formed from a softer material than the first mattress layer. Preferably the first mattress layer includes a softer inner section for comfort. According to another aspect of the present invention, there is provided a mattress for use with a hospital bed, the mattress including a first mattress layer provided with a plurality of castellations formed in an upper surface thereof, and a second mattress layer positioned over the castellations of the first mattress layer. The second mattress layer improves patient comfort, by overriding of the castellations on the surface of the patient, preventing the patient' s skin being grabbed by the castellations.

Advantageously, the second mattress layer is formed of a softer material than the first mattress layer. Advantageously, the first mattress layer is housed within a third mattress layer. Preferably, the castellations in the first mattress layer are located at the head and foot end of the mattress. Advantageously, the castellations are elliptically shaped for better pressure relief.

Embodiments of the present invention are described below, by way of example only and with reference to the accompanying drawings, in which:

Figure 1 shows an end view of a preferred embodiment of mattress;

Figure 2 shows a longitudinal cross-section of the mattress of Figure 1; Figure 3 shows in enlarged view a portion of the cross-section of Figure 2;

Figure 4 is a view in schematic form of the underside of the lower layer of the mattress of Figure 1;

Figure 5 shows in enlarged side elevational view a portion of the lower layer of the mattress of Figure 1;

Figure 6 shows in enlarged view a portion of an upper surface of a lower layer of the mattress of Figure 1; and

Figure 7 shows the mattress of Figure 1 in a bent configuration. Referring to Figure 1, one of the preferred embodiments of the invention shows mattress 10 provided with two layers: a primary lower layer 11 and an upper layer 12. In this embodiment, the lower layer 11 is 110 mm thick and upper layer 12 is 40 mm thick. Upper layer 12 has a larger footprint than the lower layer 11 so as to extend beyond the side edges and ends of the lower layer 11. The purpose of this feature is to allow the upper layer 12 to extend over a frame of a bed on which the mattress is located. The upper layer, thus, covers the frame and prevents direct contact of a patient against the frame.

The two layers 11 and 12 are preferably bonded together by a suitable adhesive or other bonding method and are enveloped in a cover 13. Along an edge of cover 13 there is provided a zip (not shown) to allow the cover 13 to be removed for washing or replacement. A flap (not shown) is provided to cover the zip. Lower layer 11 is constructed from a foam while upper layer 12 is constructed from softer elastic foam. Lower layer 11 is stiffer than upper layer 12 and provides support for a patient. Upper layer 12 is softer than lower layer 11 and provides comfort for a patient.

Further features of the layers 11 and 12 of mattress 10 can be seen in Figure 2. hi the upper surface of lower layer 11 there is provided two series of castellations 30 (described in more detail below with reference to Figure 3). It can be seen from Figure 2 that upper layer 12 overlies the castellations 30 in the upper surface of lower layer 11. The castellations 30 are provided at areas of the mattress 10 corresponding to regions of a patient's body at which pressure points occur, such as at the head and torso and at the feet.

Lower layer 11 is also provided with two series of incisions 40, 41, extending transversely across lower layer 11. hi this example, fifteen straight incisions 40 are provided in the lower surface of layer 11 and two "V-shaped" grooves 60 (described in more detail below with reference to Figure 6) spaced from incisions 40. The incisions 40 are located at the area of mattress 10 corresponding to the hip- waist area of a patient while the V-shaped

grooves 60 are located at the area of mattress 10 corresponding to the knee area of a patient. Another set of seven straight incisions 41 is provided in the upper surface of lower layer 11.

Figure 3 shows the incisions 40 and 41 in more detail. The series of straight incisions 40 in the lower surface of the layer 11 extend different depths into the body of lower layer 11, in this example being chosen to have three different depths. From the left-hand side of Figure 3 (the "head" end of the mattress), the first, sixth to eighth and thirteenth to fifteenth incisions 40 have a depth of 45 mm; the second, fifth, ninth and twelfth incisions 40 have a depth of 61 mm; and the third, fourth, tenth and eleventh incisions 40 have a depth of 70 mm. The different depths reduce the amount of compression on the top surface during profiling and the varying depths are specifically designed to provide greater pressure distribution and contact area, on that part of the body to be supported thereon. hi this embodiment, the seven incisions 41 provided hi the upper surface of lower layer 11 have a depth of 12.5 mm. It can be seen hi Figure 3, that incisions 41 are off-set with respect to incisions 40. This can also be seen in Figure 4, in which the transverse dotted lines represent incisions 40 (on lower surface) or 41 (on upper surface).

Referring again to Figure 3, the dash-dotted line 42 represents continuous mattress section through the area of the incisions 40, 41. As can be seen, this continuous mattress section has a concertina shape, allowing the lower layer 11 of the mattress to stretch. As is described below, this allows the mattress in effect to extend into or over the bed contour as the bed is reconfigured.

Figure 5 shows V-shaped grooves 60 in more detail, hi this embodiment, the troughs of grooves 60 are spaced from one another by 52 mm and an angle of substantially 16° is formed by the "V". The grooves 60 in practice act as a hinge, allowing lower layer 11 to bend without having to compress unduly, as is the case with a conventional mattress. Figure 6 shows the castellations 30 in lower layer 11 in more detail. The peaks/troughs of the castellations 30 are, in this example, spaced 50 mm from one another. The castellations have the same effect as the castellations of known mattresses, that is of reducing the contact area on the relevant portions of a patient's body to reduce the compressive effect caused by the

weight of those portions of the patient's body on the mattress. The upper layer 12 of the mattress 10 softens the feel of the castellations without losing their intended benefits.

In use, mattress 10 is placed on the support surface of a hospital bed and a patient lies thereon. When the bed is in a flat position, mattress 10 is as shown in Figure 2. If the support surfaces of the bed are moved to reconfigure the bed, for example into a sitting position, the mattress follows the contour of the bed portions by bending at the angles formed by the bed portions. For example, the bed portions can be configured into a "Z" arrangement to support a patient in a seating position, as illustrated in Figure 7.

In this configuration, the incisions 40 open up, creating smaller, separated portions of the foam mattress. This enables the lower surface of lower layer 11 to extend with respect to the corresponding part of the upper surface and so to bend in conformity with the support surfaces 70 of the bed. As the upper surface of mattress 10 compresses, incisions 41 in the upper surface of lower layer 11 allow the mattress to stretch around the bend as a result of the concertina effect provided by the combination of the incisions 40 and 41, as explained above. At the same time, the V-shaped grooves 60 close, enabling the mattress to bend in the other direction at the region corresponding to the knee area of the patient. Also, the incisions or grooves on the lower surface during profiling move along the bed support surface to counter the effect of shear on the top surface during profiling.

Figures 8, 9 and 10 show another preferred embodiment of the invention. The mattress 1 is provided with three layers: a primary lower base layer 10, a middle layer 11 and an upper layer 12. The mattress has inclined sides with the primary lower layer 10 extending up to the upper layer 12. The upper layer 12 overlies the lower layer 10 and covers the middle layer 11. The inclined sides cover the frame of a bed on which the mattress is located preventing direct contact of a patient against the frame. As with the mattress in Figure 1, the layers 10, 11 and 12 are bonded together by suitable adhesive or other bonding method and are enveloped in a cover 13.

Lower layer 10 is constructed from a foam while the middle layer 11 is constructed of a softer foam and the upper surface layer 12 is constructed of an even softer foam or viscoelastic foam, for improved patient comfort.

Further features of the layers 10, 11 and 12 can be seen in Figures 9 and 10. The lower layer 10 surrounds the middle layer 11. The middle layer 11 is provided with elliptically shaped incisions 30 extending transversely along the upper surface at the head and foot end of the mattress. The upper surface 12 overlies the incisions 30 of the middle layer and the edges of the lower layer 10.

The lower layer is provided with incisions 40 extending transversely across the lower layer centrally of the mattress.

In use, when a patient lies thereon, the head and heels have greater pressure reduction due to the elliptical incisions 30 and when the bed is profiled the incisions 40 along the lower surface of the lower layer 10 open up to allow the mattress 1 to profile with the bed.

Various modifications can be made to the above-described arrangement.

The precise number and nature of the incisions need not be exactly as described above. Other arrangements are possible. For example, the mattress could be designed to conform to particular sizes and designs of bed. The layers of the mattress need not be bonded together; they may be separable.

The mattress could, of course, be useful in applications other than hospital beds.