WO2009084058A1

WO2009084058A1 - Device for controlling the temperature of a mattress

Info

Publication number: WO2009084058A1
Application number: PCT/IT2008/000002
Authority: WO
Inventors: Giorgio Pastorino
Original assignee: Peltech S.R.L.
Priority date: 2008-01-03
Filing date: 2008-01-03
Publication date: 2009-07-09

Abstract

The device for controlling the temperature of a mattress comprises a mattress assembly(ll) including a bottom layer(12), a middle layer(13) and a top layer (14) made from a foam material, a plurality of spaced parallel open channels(16) formed in the middle layer(13) of the mattress assembly (11), a pair of flexible headers (19, 20), a plurality of flexible tubes of U-shape(21), having the branches of the U-shaped tubes (21) disposed in the channels (16), whereby all of the U- shaped tubes (21) are connected in parallel, circulating means (23) for circulating a heat transfer medium through the headers (19, 20) and U-shaped tubes(21), control means(27,28) for controlling the temperature of the heat transfer medium. The mattress assembly(ll) comprises a net or foil layer(22) of flexible and thermally conductive material sandwiched between the top (14) and middle layers (13) to cover the channels (16) provided in the middle layer (13). The U-shaped tubes (21) are arranged in the channels in an unrestrained manner.

Description

DEVICE FOR CONTROLLING THE TEMPERATURE OF A MATTRESS

Technical field The present invention relates to a device for controlling the temperature of a mattress to a desired value in an accurate and uniform manner, and in any ambient condition. Background art

It is known in the art the problem of keeping the temperature of a mattress at a value ensuring that a person can rest comfortably on the mattress in any ambient condition. Although various attempts have been made in the past to address this problem, a satisfying solution has not, as yet, been found and there is still the need for improvement of the solutions presented so far. A solution to the above problem is known, for instance, from

International patent application WO 2006/045220 disclosing a device for controlling the temperature of a bed mattress. The device comprises a bed mattress, a refrigerating/heating machine, an accumulator and a circulation pump connected in series through soft pipes. The refrigerating/heating machine may consist of a thermoelectric device. The bed mattress comprises a function layer formed of spiral tubes, or consisting of a body with holes arranged inside, though which a hot or cold liquid is passed.

A problem with this solution is that, given the length of the spiral tubes in the function layer, there is a substantial temperature differential between the inlet and outlet temperatures of the tubes. Accordingly, this requires the refrigerating/heating machine to be chosen with a greater power rating. Another problem of this prior art solution, which is related again to the spiral form of the tubes, is that the average temperature produced by adjacent tube lengths forming a loop of the spiral may vary significantly along the width of the function layer. This causes the temperature in the mattress bed to be distributed in a non uniform manner.

The drawbacks of this, as well of other similar solutions known in the art, have led the present inventors to investigate the problem of controlling the temperature of a mattress. From the researches conducted by the inventors, it was found that the control of the temperature of a mattress requires two important conditions to be satisfied for the well-being of a person resting on the mattress.

Firstly, it is required that the temperature of the mattress can be controlled at a value predetermined by the user in a most accurate and uniform manner as possible. Another requisite, then, is that the temperature variations can be kept within a very narrow range about a predetermined value, in order to avoid a feeling of discomfort or disturbance in the user. Disclosure of the invention The present invention is aimed at the task of fulfilling these requisites, and of obviating the drawbacks of the solutions known in the art. In view of the above objective, the present invention provides a device for controlling the temperature of a mattress, whereby the temperature of the mattress can be controlled accurately and uniformly at a desired value in a more simple and effective manner, and in any ambient condition.

This task is accomplished with a device for controlling the temperature of a mattress comprising: - a mattress assembly including a bottom layer, a middle layer and a top layer made from a foam material,

- a plurality of spaced parallel open channels formed in said middle layer of the mattress assembly, - first and second opposite recessed portions formed in said middle layer, proximate to the ends thereof, and arranged generally perpendicular to said channels and communicating therewith,

- a pair of flexible headers extending in said first recessed portion of the middle layer,

- a plurality of flexible tubes of U-shape, having the branches of the U-shaped tubes disposed in said channels and one branch of each U-shaped tube being connected to one of said headers, while the other branch of each U-shaped tube is connected to the other header, whereby all of said U-shaped tubes are connected in parallel, and having the bight portion of the U- shaped tubes disposed in said second recessed portion of the middle layer,

- circulating means for circulating a heat transfer medium through said headers and U-shaped tubes,

- control means for controlling the temperature of said heat transfer medium, characterised in that said mattress assembly comprises a net or foil layer of flexible and thermally conductive material sandwiched between said top and middle layers to cover said channels provided in the middle layer, and said U-shaped tubes are arranged in said channels in an unrestrained manner so that said middle layer of the mattress assembly is allowed to be deformed without restriction, by a certain amount, in response to an applied force produced by a user's body lying on said mattress assembly. Brief description of the invention

The device of the invention will be described with reference to an exemplifying, and non limiting embodiment, in connection with the accompanying drawings, wherein:

Figure 1 is a top view of the device according to the present invention,

Figure 2 is a cross-sectional view of the device according to the present invention taken along line II-II of Figure 1 ,

Figure 3 is a cross-sectional view of the device according to the present invention taken along line HI-III of Figure 1, and

Figure 4 is a top view of a variant of the device according to the present invention.

Best mode for carrying out the invention

Referring to Figures 1-3 of the drawings, there is shown diagrammatically the device for controlling the temperature of a mattress according to the present invention, generally designated by 10.

The device of the invention includes a mattress assembly 11 having an internal construction which may be formed of a bottom layer 12, a middle layer 13 and a top layer 14. These layers can be made of any suitable material, but in a preferred embodiment they are made of foam materials having different physical and chemical characteristics. In this way, the different foam materials are directed to specific purposes, such as providing support or comfort. For instance, the lower layer may have a greater thickness and may be made of a foam material having a greater degree of firmness, while the middle layer and the top layer may have a smaller thickness and may be made of a foam material having a lower degree of firmness. Suitable foam materials that can be used for the mattress assembly are polyurethane foams and viscoelastic or memory foams. Preferably, the bottom layer 12 is made of a polyurethane foam, whereas the middle layer 13 is made of a memory foam.

The layers of the mattress assembly may merely be staked or they can be cemented or stitched together. A removable and interchangeable casing 15 made of a flexible and thermally conductive material may be provided for enclosing the mattress assembly.

It will be understood that modifications to the above preferred construction of the mattress assembly may be made as might occur to one with skill in the field of the invention. In particular, although the layers are preferably made of a foam material, the mattress assembly may be made from a combination of foam layers and spring mattress layers. Also, some layers may be provided as a continuous body having uniform properties or a continuous body with different local properties from zone to zone. If desired, the bottom layer and the middle layer may be substituted by a single layer made of foam material having suitable thickness and firmness.

Returning now to the preferred construction of the mattress assembly shown in the Figures 1-3 of the drawings and considering, in particular, the middle layer 13, it can be seen that this layer embodies a plurality of separate parallel open channels 16. The channels 16 extend lengthwise of the mattress assembly and terminate in opposite recessed portions 17 and 18 provided in the middle layer 13. These recessed portions are located proximate to the ends of the mattress assembly and are arranged generally perpendicular to the channels 16. For the purpose of allowing the temperature of the middle layer 13 of the mattress assembly to be controlled, there are disposed within the recessed portion 17 of the middle layer a pair of parallel headers, designated by the reference numerals 19 and 20, which are adapted to supply a suitable heat transfer medium to the middle layer 13. These headers may be of identical configuration and the header 19 may be designated as the inlet header, while the header 20 may be designated as the outlet header. Accordingly, the arrows in Figure 1 of the drawings show the direction of flow of the heat transfer medium in the headers. Preferably, the headers are formed of a plastic tubing which may include tubing of polyethylene or other suitable material.

In order to distribute the heat transfer medium supplied by the inlet header 19 in a most uniform manner as possible throughout the middle layer 13, there are provided a plurality of small tubes, designated by the reference numeral 21, each arranged in a separate channel 16. Preferably, the tubes 21 are also formed of a plastic tubing such as polyethylene or other suitable material. The tubes are shown in the form of a U with the bight portion of the U disposed in the recessed portion 18 at one end of the middle layer 13 and the legs of the U connected to the headers 19 and 20, respectively, disposed in the recessed portion 17 at the opposite end of the middle layer 13. In this way, all the U-shaped tubes 21 are connected in parallel with each other. Assuming that the heat loss in the headers 19, 20 is negligible, it is apparent that a substantially uniform average temperature will be produced by the U-shaped tubes 21 throughout the middle layer 13.

To ensure that, in response to an applied force produced by a user's body lying on the mattress assembly, the middle layer 13 is allowed to be deformed by a certain amount, without being restrained by the U-shaped tubes 21. To this purpose, each leg of the U-shaped /

tubes 21 is disposed to lie unrestrained within the corresponding channel 16.

According to the invention, in order to further reduce the friction between the legs of the U-shaped tubes 21 and the bottom and side walls of the channels 16 a suitable fabric may be arranged to cover the bottom and side walls of the channels 16. Preferably, this fabric is made of a thermally conductive woven material.

It will be understood that the number and size of the U-shaped tubes 21, as well as the size of the headers 19, 20 may be varied according to the size of the mattress assembly 11. Also, as depicted in Figure 4 of the drawings, a variant of the device according to the present invention may comprise two or more arrays of U-shaped tubes 21, as described above, which are disposed in different zones of the middle layer 13 and are each connected to corresponding pairs of headers 19, 20. In this way, different zones of the middle layer 13 can be independently and individually controlled in temperature according to the user's preference or to specific needs which may arise, for instance, in the application of thermal therapy to a patient's body.

According to a further variant of the invention, which is not shown in the drawings, the recessed portion 17 accommodating the headers 19 and 20 may be formed in the bottom layer 12 of the mattress assembly 11, for the purpose of avoiding that the headers 19,

20 might cause a disturbance to the user. In this case, the connection of the headers 19, 20 to the U-shaped tubes 21 may be made through suitable openings formed in the middle layer 13 and communicating with the channels 16.

As it is an aim of the present invention to ensure a uniform temperature distribution from one end of the middle layer 13 to the other, there is further provided a net or foil layer 22 of a thermally conductive and flexible material, which is sandwiched between the middle layer 13 and the top layer 14. It is apparent that since the channels 16 are open toward the upper surface of the middle layer 13, the bottom facing surface of the net or foil layer 22, under the action of a body lying on the mattress assembly 11, can come into contact with the top facing outer surface of the tubes 21 disposed in the channels 16. In this way, heat can be exchanged between the tubes 21 and the net or foil layer 22 and be distributed uniformly throughout the middle layer 13. The net or foil layer 22 also serves the purposes of preventing the tubes 21 from coming out of the channels 16 and of relieving the uncomfortable feeling of pressure which may be caused by the tubes on the user's body. The net or foil layer 22 may be formed of a metal material such as copper, aluminium, or alloys thereof. Alternatively, a thermally conductive polymer material can be used for the net or foil layer 21. A suitable polymer material is, for example, Kapton^® available from E.I. du Pont de Nemours and Co.

From the above description it is apparent that there is provided an arrangement for circulating the heat transfer medium through the headers 19, 20 and the U-shaped tubes 21. For this purpose there is provided a pump unit 23 which is connected by suitable means including couplings 24 and flexible tubes 25 to the headers 19, 20. Also, as conventional in systems of this kind, a filling and expansion tank 26 is provided for the heat transfer medium.

Clearly, some means must also be provided to control the temperature of the heat transfer medium being circulated. Since the present invention is aimed equally to heating and cooling the mattress assembly 11, there is provided a heat exchanger 27 disposed in heat exchange relationship with the heat transfer medium circulating in the tubes 25. Preferably, a thermoelectric module 28 exhibiting a Peltier effect is provided for selectively heating and cooling the heat transfer medium in the heat exchanger 27. The control means for controlling the temperature of the heat transfer medium may be responsive to the temperature of said heat transfer medium at some desired point of the header 19, 20 or of the connection of the tubes 25 to the heat exchanger. A suitable thermoelectric module is, for instance, the model GEOtronic^® available from Peltech S.r.L As the details of this, as well as other similar thermoelectric modules are well known to those skilled in such art, further description of the details is not given here.

With the arrangement described above, it will be appreciated that the temperature of the heat transfer medium can be controlled in a very accurate manner. Furthermore, since the thermoelectric module of the kind mentioned above is provided with an electronic controller, the temperature of the heat transfer medium can be controlled in a continuous manner, instead than in an intermittent manner as with conventional thermostatic control means.

While the device has been described with reference to a preferred embodiment, a person skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of what is claimed. Therefore, it is intended that the claims not be limited to the particular embodiment disclosed, but include all embodiments falling within the scope of the appended claims.

Claims

1. A device for controlling the temperature of a mattress comprising:

- a mattress assembly including a bottom layer, a middle layer and a top layer made from a foam material, - a plurality of spaced parallel open channels formed in said middle layer of the mattress assembly,

- first and second opposite recessed portions formed in said middle layer, proximate to the ends thereof, and arranged generally perpendicular to said channels and communicating therewith,

- control means for controlling the temperature of said heat transfer medium, characterised in that said mattress assembly comprises a net or foil layer of flexible and thermally conductive material sandwiched between said top and middle layers to cover said channels provided in the middle layer, and said U-shaped tubes are arranged in said channels in an unrestrained manner so that said middle layer of the mattress assembly is allowed to be deformed without restriction, by a certain amount, in response to an applied force produced by a user's body lying on said mattress assembly.

2. The device of claim 1, characterised in that a casing made of a flexible and thermally conductive material is provided for enclosing the mattress assembly.

3. The device of claim 1, characterised in that a covering layer made of a thermally conductive fabric is provided for lining the side and bottom walls of the channels, said covering layer reducing the friction coefficient between said U-shaped tubes and said side and bottom walls of the channels.

4. The device of claim 1, characterised in that the top layer extends beyond the edges of the net or foil layer.

5. The device of claim 1, characterised in that the top layer is coextensive with the net or foil layer.

6. The device of claims 4 or 5, characterised in that the top layer is glued to the middle layer of the mattress assembly.

7. The device of claims 4 or 5, characterised in that the top layer is stitched to the middle layer of the mattress assembly.

8. The device of claim 1, characterised in that the flexible and thermally conductive material of the net or foil layer is a metal material.

9. The device of claim 8, characterised in that the metal material is aluminium or copper.

10. The device of claim 1, characterised in that the flexible and thermally conductive material of the net or foil layer is a synthetic resin.

11. The device of claim 10, characterised in that the synthetic resin is polyimide.

11. The device of claim 1, characterised in that said first recessed portion accommodating said headers is located in the upper portion of said middle layer of the mattress assembly.

12. The device of claim 1, characterised in that said first recessed portion accommodating said headers is located in the lower portion of said middle layer of the mattress assembly.

13. The device of claim 1, characterised in that said bottom, middle and top layers of the mattress assembly are made of a foam material.

14. The device of claim 13, characterised in that the foam materials of the bottom, middle and top layers of the mattress assembly exhibit different chemical and physical characteristics.

15. The device of claim 13, characterised in that said foam materials of the bottom, middle and top layers of the mattress assembly include polyurethane foams and viscoelastic or memory foams.

16. The device of claim 1, characterised in that said mattress assembly is made from a combination of foam layers and spring mattress layers.

17. The device of claim 1, characterised in that the circulating means and the control means are located remotely relative to said mattress assembly, and flexible conduits are included for connecting said headers, said circulating means and said control means to circulate said heat transfer medium between said control means and said headers through said circulating means.

18. The device of claim 17, characterised in that a filling and expansion tank is provided for the heat transfer medium and is operatively connected between one of the headers and the control means via said flexible conduits.

19. The device of claim 1, characterised in that the control means for controlling the temperature of the fluid medium is responsive to the temperature of said fluid medium at the connection of said flexible conduits to said control means.

20. The device of claim 1, characterised in that the control means for controlling the temperature of the fluid medium operates a thermoelectric device exhibiting a Peltier effect to cause the temperature of the fluid medium to be reduced or increased.