The present invention is concerned with .the preventio of Sudden Infant Death Syndrome (SIDS) otherwise known a cot death and _Λ more particularly, with a mattress for th prevention of cot death.

Cot death is a tragic phenomena where infants betwee about one month and six months of age cease to breath whilst asleep in their cots and die. The reasons for this are not well understood but to date mattress design does not seem to have been addressed as a possible cause as, although there are numerous proposals for improved mattresses, none seem concerned with means for avoiding cot death.

For example, Australian Application No. 38782/78 discloses a ventilated bed construction which has as one of its objects to provide a bed which maintains body warmth but can be kept cool in hot weather. A further object is to provide a bed wherein the bed quilt can be dried in situ if it is wet, for example by perspiration, and a still further object is to provide a bed wherein the room air may be cleaned by disinfection and/or deodourization. These objects are said to be achieved by providing a bed which has a large open space beneath the mattress extending into a vertical space adjacent the mattress (somewhat like a bedhead) which contains a heater element, a germicidal lamp, a deodourizer and/or a humidifier. Air which is heated, sterilized, deodourized and/or humidity-controlled is able to circulate within the space and through the mattress to achieve the objects of the invention. The specification does not discuss cot death and most certainly does not

describe a mattress for preventing cot death or any method of or means for preventing cot death. Nor indeed does the specification envisage a mattress designed for a baby but rather illustrates a single piece inner spring mattress designed for adult use.

Similarly, Australian Patent Application No. 41055/85 describes a foam mattress with ventilation passages extending therethrough so that air may circulate through the foam mattress to prevent excessive heating or cooling of the body contacting the mattress and to prevent build up of excessive moisture in the contact area. This seems largely aimed at the prevention of pressure sores in long term bed¬ ridden patients and, once again, there is no adaption of the mattress for babies nor any description of means for preventing cot death in babies.

A variety of other systems for heating or cooling beds have been proposed in United States Patents Nos. 2585517, 2601189, 3101488, 3266064 and 4305168. None of these systems are adapted for use by babies nor do they describe means for the prevention of cot death in babies.

It is therefore an object of the present invention to provide a mattress designed specifically for babies and to prevent cot death in babies.

Accordingly, in one broad aspect the invention resides in a baby's mattress for the prevention of cot death comprising a first piece having a frame which has an open top and at least one side that is at least partially open to allow air to circulate within the frame, the top being

covered by a gas permeable material that is fixed to the frame, the first piece being adapted to support the baby's head; and a second piece adapted to support the baby's torso.

In a further broad aspect the invention resides in a method for prevention of cot death in babies comprising the steps of:-

(1) providing a mattress having a gas permeable portion on its upper surface through which air can circulate;

(2) placing a baby on the mattress with its head on the gas permeable portion; and

(3) allowing the baby to sleep with its head on the gas permeable portion.

Preferably, the gas permeable part of the mattress is made of a woven net material which is also liquid permeable.

While not wishing to be bound by theory, it is believed that a factor in cot death is the build up of exhaled air (rich in carbon dioxide and poor in oxygen) around a sleeping baby's face. This build up is accelerated When a baby vomits or salivates while asleep since this wets the bedsheet and exhaled air passing over a wet bedsheet is rapidly cooled by evaporation of the liquid. This results in a cooled patch of exhaled air settling on the mattress near the baby's face beneath the fresh air which remains at room temperature. It is hypothesized that continually re- breathing the exhaled air is a factor in cot death.

It is also noted that a majority of cot death babies are found face down. While not wishing to be bound by

theory, sufficient air may not reach a baby's face if it is laid face down or if it rolls onto its face, and this may be a factor in cot death. Also, it is postulated that overheating of the baby may be a factor.

As will be appreciated by those skilled in the art, the. provision of a gas permeable portion of a mattress on which a baby's head is placed will allow the cooled exhaled air to sink through the mattress away from the baby's face. Since air may circulate beneath the mattress the carbon dioxide rich air is dispersed. The baby may also breathe freely even when lying face down. It will also be appreciated that when a liquid permeable woven net is employed, vomit or saliva will not accumulate and therefore the baby cannot lie in this nor does it wet the bedsheet. The woven, net also provides ventilation that keeps the baby's head cool.

In a particularly preferred method according to the invention, the mattress has first and second pieces as described above and means for restraining the baby so that its head remains on the first piece while it sleeps. The restraining means preferably are constituted by a third piece of the mattress which can be placed on top of the second piece against the baby's feet so that the baby cannot slide down the mattress. Typically, the second and third pieces of the mattress are made of conventional mattress materials such as foam or may even be small inner spring mattresses. The third piece is generally the same size as the first piece so that once the baby is old enough that the danger of cot death has passed the third piece may replace

the first piece. This allows the mattress to be used as conventional mattress albeit in two pieces, until the bab is too large for the cot.

The third piece may be fixed to the second piece in an way but conveniently it is secured thereto by self-clippin strips such as VELCRO (registered trademark) strips. Conveniently, the first and second pieces may also be fixe together by self-clipping strips. The gas permeabl materials may also be fixed to the frame in any way possibl including by means of self-clipping strips.

. The bottom of the frame may be removable to allo additional air to circulate beneath the mattress. This is particularly useful in hot climates where it provides additional cooling and prevents the baby from overheating. In cooler climates it is preferable to have the bottom closed to prevent draughts around the baby.

In a further broad aspect the invention resides in a baby's co t which has a mattress as described above placed therein. Where the mattress includes restraining means to prevent the baby sliding down the mattress under the bedclothes, it will be appreciated by those skilled in the art that the walls of the cot will prevent movement of the baby off the mattress in any other direction. The baby's head cannot move off the gas permeable portion of the mattress.

In order that the invention may be more readily understood, reference will now be made to the accompanying

drawings in which:-

Fig. 1 is a perspective view of the second and third pieces of the mattress pushed together for use in a similar manner to a conventional mattress; Fig. 2 is a similar representation to Fig. 1 where the third piece is placed on top of the second piece; Fig. 3 is a perspective view of the frame that forms a part of the first piece of a mattress in accordance with the invention;

Fig. 4 shows the woven net fabric that is used to cover the frame shown in Fig. 3;

Fig. 5 is a perspective view of a mattress in accordance with the invention;

Fig. 6 shows an alternate form of the frame of a mattress in accordance with the invention; and

Fig. 7 is a cross-section through line 7-7 in Fig 6.

Referring now to Fig 1, it may be seen that the mattress 10 when it is to be used by a baby that is old enough that the danger of cot death has passed has a third piece 11 and a second piece 12 lying adjacent one another.

The third piece 11 and second piece 12 are both made like conventional mattresses and may, for example, be pieces of foam rubber. They are ^• simply pushed together or may be fastened together, for example by self-clipping strips (not shown) on the adjoining faces to form a mattress suitable for an older baby to sleep on. On the top surface of the second piece 12, self-clipping strips 13, 15, in this case

VELCRO strips, are provided to allow the third piece 11 of

the mattress to be fixed thereto. The third piece 1 includes self-clipping strips 16, 17 to allow for its attachment to the second piece 12.

Fig. 2 shows the third piece 11 of the mattres ^• attached to the second piece 12 via strips 13, 15 on th second piece and strips 16, 17 on the third piece which ar pushed together so that they stick to each other» Th position of the third piece 11 on the second piece 12 can b varied simply by placing the third piece in the desire position as the strips 13, 15 are sufficiently long that they will hold the third piece in a position anywhere between the front end 19 being almost on strip 14, and the back end 20 being coincident with the back edge 21 of the second piece 12. This allows the third piece 11 to be placed against the feet of the baby no matter what length the baby is and allows adjustments to be made as the baby grows.

Fig. 3 illustrates the frame 22 of the first piece 18 which replaces the third piece 11 when the mattress 10 is to be used for a baby still at an age where it is susceptible to cot death. Each of the sides 24, 25, 26 in this case are fitted with self-clipping strips 27, 28, 29 which extend right along their top surfaces and/or along the top edge. These allow the attachment of a gas permeable material over the top of the frame 22. It may also be noted that the bottom 30 of the frame 22 is detachable. Also, side 26 is partly open since it does not extend fully to bottom 30, leaving a gap 31. This allows air to circulate within the

first piece 18. Cross-brace 23 is provided to strengthen the frame 22.

Fig. 4 shows a gas permeable material which in this case is a woven net fabric 32 (the net is shown only in a portion 33) which allows gases (for example, air exhaled by a baby resting thereon) and liquid to pass through. The fabric 32 is fitted all around with self-clipping strips 34, 35, 36, 37 which are capable of engaging strips 27, 28, 29 on the frame 22 and strip 14 on the second piece 12 to secure it to the mattress 10. This is best seen in Fig. 5 where the entire mattress assembly is shown.

In Fig. 5 it may be seen that a baby can be placed with its head on the woven net fabric 32 stretched over frame 22 which together constitute the first piece 18,- its torso on second piece 12 with its feet against the end 20 of third piece 11. When the mattress is placed in a cot this arrangement ensures that the baby's head will remain on the woven net fabric 32.

As the fabric 32 is gas permeable the baby's breath will not accumulate in a layer above the mattress around the face of the body. _. Air can enter through gap 31 and circulate within frame 22 and through the gas permeable fabric 32 to disperse the carbon dioxide rich exhaled air and introduce fresh air around the baby's face as well as cooling the baby.

Furthermore, as the fabric 32 is also liquid permeable, vomit and saliva pass through it. The baby cannot lie in

its own vomit or saliva, and the liquid does not wet the bedshee .

Fig. 6 shows a plastic frame 38 that has been injection moulded. The frame comprises sides 39, 40 joined by cross¬ beams 41, 42 which slide into the slots 44, 45, 46, 47 in the sides. As best seen in Fig. 7, the frame is covered by woven net fabric 43 which is the same as the fabric described above. However, to attach the fabric 32 to frame 38, the frame is provided with rod 48 which slides into a loop 49 in the fabric 43. The fabric 43 is stretched over the frame 38. Then split rod 50 with ratchet knob 51 attached thereto is pushed through the loop 52 in the fabric 43. The fabric is tightened by turning the ratchet knob whereupon the assembly may be used as the first piece of the mattress in place of the assembly shown in Fig. 3.

Various modifications apparent to those skilled in the art may be made without departing from the broad ambit and scope of the invention as defined by the appended claims.