GB2179550A - Duvets - Google Patents

Abstract

A duvet comprises at least one layer of thermally insulating padding 10, and an electrically heatable flexible panel 12. The insulating padding 10 is attached to a surface of the heatable panel 12, preferably the heatable panel 12 has insulating padding 10 on each of its opposing faces. Either each of the insulating padding layers or the whole duvet may be covered with a covering material 48. The heatable panel 12 comprises two layers of material 24 and 26 secured together at intervals 30, the tunnels formed enclosing heating elements 28 and optionally, temperature sensor wires 46. Layers of thermal insulation 42 and 44 may be secured to the heatable panel 12 at intervals 36 by stitching or welding. Control means (not shown) may be provided to control the amount of heating current supplied to the heatable panel 12. <IMAGE>

Description

SPECIFICATION Duvets This invention relates to duvets, which are also known as continental quilts.

The expression "duvet", as used herein, means a bedcover which is intended usually to be used without blankets and which comprises padding or filling enclosed between two layers which are usually of cloth or another fabric.

Different duvets provide different amounts of heat insulation, the amount of insulation being defined quantitively by the so-called "tog" value of the duvet. British Standard BS 5335 defines "tog" as a unit of thermal insulation of a continental quilt (duvet), the tog value of a duvet being equal to ten times the temperature difference (in degrees Celsius) between its two faces when the flow of heat across it is equal to one watt per square metre. That is, 10tog = 1"C.m2NV.

A high tog value quilt is generally intended to be used in cold surroundings: it is relatively dense, and provides a relatively high amount of heat insulation, as compared to a low tog value quilt, which is generally intended to be used in relatively warm surroundings.

The temperature of the average bedroom varies considerably over the seasons. Thus, a high tog value duvet may lead to the sleeper becoming uncomfortably warm during summer (and, perhaps, in the spring and autumn), while a low tog value duvet may lead to the sleeper becoming cold during winter.

One solution to this problem is to purchase both a high tog value duvet and a low tog value duvet for each bed and to select for use, on any night, the duvet most appropriate to the ambient temperature.

This involves undesirable expense, i.e. the cost of two duvets per bed, and will often (especially in small households) give rise to the problem of finding storage space for a set of extra duvets.

Moreover, it will generally be impractical or at least excessively inconvenient to change duvets in accordance with day-to-day temperature changes.

In practice, the high tog value duvet will be used in the winter and the low tog value duvet will be used in the summer. In this case, in the event Of unseasonal weather (a by no means infrequent phenomenon in the UK), the sleeper may become too hot in winter or too cold in summer. Further, in the event of moderate temperature, both duvets may be unsuitable in that the high tog value duvet may be too warm and the low tog value too cold. In short, this solution is not satisfactory.

Another solution to the problem is for the user to possess only a low tog value duvet for use when the temperature is high and to supplement the duvet with one or more blankets when the temperature is lower. As well as being subject to some of the disadvantages of the first-mentioned solution, this solution is fundamentally unsatisfactory in that it negates certain advantageous features (easier bedmaking, and no need to possess, clean and store blankets) associated with the use of a duvet.

What is needed is a duvet which, in effect, has a variable tog rating.

According to the present invention, there is provided a duvetwhich incorporates an electrically heatableflexible panel.

If the heatable panel is not energised, the duvet has a relatively low tog value and can be used in relatively warm conditions. In relatively cold conditions, the heatable panel can be energised (to pre-heatthe bed and/or to heat the bed while occupied) thereby producing heating which is equivalent to increasing the tog value of the duvet.

Preferably a duvet is provided having one layer of padding attached to one surface of the heatable panel.

If, as is preferred, the duvet is provided with control means to enable the amount of electrical power supplied to the heatable panel to be varied, the amount of heating (and therefore the effective tog value) of the duvet can be varied more precisely to suit the ambient temperature. The control means may in fact be responsive to the ambient temperature to optimise user comfort.

The invention will now be further described, by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which: Figure 1 is a somewhat schematic sectional view of the components of a duvet embodying the invention prior to their being completely secured together; Figure 2 is a sectional view of the duvet after its components have been completely secured together; and Figure 3 is a sectional view of an alternative embodiment of the duvetafter its components have been completely secured together.

Figure 1 of the drawings shows a duvet embodying the invention, prior to the components being completely secured together. The duvet comprises a low tog value insulating portion or panel 10 and an electrically heatable flexible panel 12.

The insulating portion 10 comprises fabric layers 14, 16 enclosing a fibre filling or padding 18, which may be of polyester. Since the layer 14 is, in this embodiment, an outer layer of the duvet and thus may come into contact with the sleeper if the duvet is not put into a cover before use, it is preferably of a non-allergenic material. The layer 16 may be of any suitable fabric, preferably a lightweight fabric.

The heating panel 12 may be constructed in accordance with avarietyoftechniques suitable for the construction of electric blankets, in particular electric over-blankets. In this embodiment the heating panel 12 comprises outer layers 20 and 22, inner layers 24 and 26 and at least one electrical heating wire or element 28 (Figure 2) which is laid out in runs between the inner layers 24 and 26 in a manner which may be similar to that in which a heating element of an electric blanket is laid out.

Alternatively there may be more than one heating element 28, connectable so as to provide a number of heating combinations.

The outer layer 20 which, when the construction of the duvet is complete, is intended to face the insulating portion 10, may comprise a layer of lightweight fabric and scrim. Since the other outer layer 22 is, in this embodiment, an outer layer of the duvet and thus may come into contact with the sleeper if the duvet is not put into a cover before use, it is preferably a layer of a non-allergenic fabric.

According to one form of the illustrated embodiment, the inner layers 24 and 26 comprise weldable fibres. In this case, the outer layers 20 and 22 and the inner layers 24 and 26 can be welded together by iocal heating (direct or radio-frequency) of the heating panel 12 to form tunnels to enclose the runs of the heating element 28, for example along lines 30 (Figure 2), which causes the weldable fibres of the inner layers 24 and 26 to become secured locally to each other and to the outer layers 20and22.

According to another form of the illustrated embodiment, the inner layers 24 and 26 may be of non-weldable fibres and layers 32 and 34 made of a hot-melt material (that is a material that melts when heated to become, in effect, an adhesive) are disposed where shown in Figure 1 between the inner layers 24 and 26 and the outer layers 20 and 22. The hot melt layers 32 and 34 can then be heated locally (by direct or radio-frequency heating) to join together the inner layers 24 and 26 and the outer layers 20 and 22, in a manner forming tunnels for the runs of the heating element 28, to achieve a construction much the same as that achieved by employing the welded fibre technique.

Both of the above-described techniques for assembling the heating panel 12 are known perse in the electric blanket art and either of these techniques (and, indeed, others known in that art) can be used to form the heating panel 12.

Figure 2 of the drawings shows the completed duvet. The construction of the heating panel 12 has been completed as described above and the heating panel 12 has been secured to the insulating portion 10. In the arrangement illustrated in Figure 2, the heating panel 12 and the insulating portion 10 have been secured together by sewing or stitching along lines 36 at a sewing pitch 38, an interlocking overseam 40 being shown at the periphery. It will be noted that the sewing produces a quilted effect on the insulating portion 10, the sewing tending to stabilise the insulating portion 10 against the effects of washing, spinning, tumbling, shaking etc. during which the fibres of the filling or padding 18 may migrate unless restrained by the pockets formed by the sewing.

Instead of or as well as securing together the insulating portion 10 and the heating panel 12 by stitching, they could be secured together by some othertechnique, such as by welding or bythe use of an adhesive. If the technique employed does not result in the insulating portion 10 becoming quilted, the insulating portion is preferably (but not essentially) quilted in some other way, for example by stitching it together before it is fastened to the heating panel 12.

In the arrangement described above, the assembly ofthe heating panel 12 is completed before it is secured to the insulating portion 10. This feature is, however, not essential, in that it is within the scope of the invention for the securement together of the appropriate layers of the heating panel 12 and the securement of the heating panel 12 to the insulating portion 10 to be accomplished by a single operation, for example by welding right through the complete structure.

The invention as so far described by way of illustrative example can, of course, be embodied in various other ways. For instance, although in the illustrated duvet the insulating portion 10 and the heating panel 12 are secured together in face-to-face relationship, it is within the scope of the invention to employ an arrangement in which the heating panel 12 is not adjacent to a face of the duvet. For example, a respective insulating portion 10 could be positioned adjacent to (and preferably secured to) each face of the heating panel 12.

Figure 3 shows an alternative embodiment of the completed duvet. In this instance the heating panel 12 is incorporated into the duvet and has insulating portions 10 secured to each face. The heating panel 12 may be made from lightweight material. This material could be a loosely woven scrim, in which the warp and weft are woven so as to form tunnels for accommodating the heating elements 28.

Alternatively, this material may be of a weldable or of hot melt type. If two layers of this type of material are used they are joined at intervals along the lines 30, to form tunnels which are used for containing the heating elements 28. Additionally the heating element or elements 28 may have a sensor wire or wires 46 running adjacent to them in the tunnels, the sensor wires 46 being capable of providing temperature information to a controller (not shown) for controlling the amount of heat input by the heating elements 28. The heating panel 12 may include one or more heating elements 28 arranged to run through the heating panel 12 and be connectable to a controller via a termination plug (not shown). The heating panel 12 may have secured to its faces two layers of insulating material 42 and 44 of different types.For example, the upper layer 42 in the figure, could be a lightly resinated hollow polyester fibre having a weight of approximately 125 g/m2 (41 oz/m2). The lower layer 44 could be a layer of lightly resinated fibres having a weight of 40 g/m2 (12 oz/m2). These two different layers 42 and 44 may have different nominal thicknesses of 35 mm and 12 mm respectively, from which it is apparent that the heating panel 12 is not centrally located in the assembled duvet. The layers 42 and 44 of insulating material may be covered by an outer layer 48 conveniently made, for example, from polyester cotton sheeting. A quilting effect may be produced by stitching along a line 36. The stitches have the advantage of holding together the different layers of the duvet and preventing migration of the layers of insulating material 42,44 or the heater panel 12. As can be seen from Figure 3 the stitch lines 36 need not be equal in number to the stitch lines 30. Preferably the pitch 38 of the stitch lines 36 is at least 15 cm and normally about 25 cm. Such a large pitch for the stitch lines 30 would not be satisfactory becauuse it would not sufficiently limit the movement of the heating elements 28. (Excessive movement of the heating elements 28 might result in their bunching and rucking and lead to excessive localized heating with its attendant dangers). Clearly the ratio shown is not one which must be rigidly adhered to and alternatives providing satisfactory service can be envisaged.

In use, the duvet is laid on a bed. (It can, if desired, be put into a duvet cover). The duvet can be positioned either way up, in the case of the single layer of insulating portion 10, that is with either the heating panel 12 adjacent to the bed (as shown) or the insulating portion 10 adjacent to the bed, according to user preference. Similarly, in the alternative embodiment having two layers of insulationg it may be arranged either way up. If the ambient temperature is high, the heating panel 12 is not energised. If the ambient temperature is low, the heating panel 12 is energised. The heating panel 12 may in this case be energised for a period before the bed is occupied (pre-heating) and/or it may be energised while the bed is occupied (all-night heating).

Conveniently the heating elements 28 and the associated sensor wires 46 may be shuttled through the tunnels formed between the layers of the heating panel 12, the tunnels having a 5 cm pitch. At intervals of approximately 25 cms a wider channel may be formed, the wider channel being used to accommodate a stitching line (such as stitching line 36) securing all the component layers together. The use of relatively wide channels located at 25 cm intervals, which are used for accommodating the stitches holding the insulating portions to the heating panel 12, results in a duvet having draping qualities more like those of a conventional duvet than an electric blanket.Additionally, the use of wide pitch stitching has the advantage that the thickness of the insulating portions 10 used may be increased with a consequently enhanced visual appearance and thermal insulation performance without causing significant constructional difficulties.

The heating elements 28 may be connectable directly to an electrical power supply, in which case the amount of heating is controllable only by virtue of the user determining for how long the heating elements 28 are connected to the supply. Such an arrangement has the advantages of cheapness and simplicity and should be satisfactory in operation.

Preferably, however, the heating element (or elements) 28 is connectable to the electrical power supply via control means to enable the amount of electrical power supplied to the heating panel 12 to be varied, either in steps or (preferably) steplessly (infinitely variable control). Various forms of such control means known in the electric blanket art may be used for this purpose.

According to a simple form of control means, at least two different heating outputs can be selected (e.g. ac heating current supplied in a non-rectified form or a half-wave rectified form). Thus, the user could select a higher heat output in cold weather and a lower heat output in less cold weather.

Alternatively, the user might select the higher output for pre-heating and then select the lower output for all-night heating when he comes to occupy the bed.

According to a more preferred form of control means, which provides a finer control of heat output, the heat output can be varied in a stepless manner, for example by controlling one or more thyristors or triacs through which current flows from the supply to the heating panel.

A particularly preferred form of control means, which may be similar to those employed in electric over-blankets, incorporates means responsive to ambient temperature to regulate the degree of heating, preferably to a level chosen by the user by operation of the control means, in order to optimise user comfort by maintaining a desired temperature, thereby compensating for temperature differences during the course of the night as well as day-to-day and seasonal temperature variations. Such temperature sensor means are shown as the sensor wires 46 in Figure 3. These known sensor wires are locatable in the vicinity of the heating elements 28 to provide a temperature sensing function along the length of the heating elements 28.This is a particularly useful safety feature because in the event that one of the heating elements 28 should become folded or damaged the sensor wire 46 can detect the local increase in temperature and relay signals to the control means to cause it to shut off the power supply to the heating elements 28.

Alternative known constructions may be used in which the heating element or elements 28 and sensor wire or wires 46 may be replaced by other known heater element arrangements (not shown), in which a heating conductor or wire is arranged coaxially with a sensor conductor or wire and spaced apart from it by a temperature sensitive material.

As will be appreciated, the above-described duvet shares with conventional duvets the advantages of easier bed-making and (if enclosed in a duvet cover) the possibility of changing the appearance of the bed by changing the cover. Also, as with conventional duvets, it removes or at least reduces the need to possess, clean and store blankets.

Unlike conventional duvets, however, it possesses the advantage that its tog value can in effect be changed.

Claims (18)

1. A duvet which incorporates an electrically heatable flexible panel.

2. A duvet according to claim 1 having one layer of thermally insulating padding attached to one surface of the heatable panel.

3. A duvet according to claim 1 having two layers of thermally insulating padding attached to respective opposing surfaces of the heatable panel.

4. A duvet according to claim 2 or claim 3 in which the layer or layers of padding are each covered with a sheet type covering material.

5. A duvet according to any one of the preceding claims in which the electrically heatable flexible panel comprises at least one layer of flexible material, the flexible material being arranged to enclose at least one flexible heating wire or heating element which is laid out in runs.

6. A duvet according to claim 5 in which the flexible material oftheheatableflexible panel is weldable, the panel being formed from one or more layers which are welded to form tunnels for enclosing runs of the heating wire or heating element.

7. A duvet according to claim 6 and in which the welding used to form tunnels for containing the heating wire or heating element has been carried out in a single operation.

8. A duvet according to claim 5 in which the heatable panel is formed from one or more layers of flexible material which are stitched to form tunnels for enclosing runs of the heating wire or heating element.

9. A duvet according to any one of claims 5 to 7 in which the layer or layers of flexible material forming the heatable panel layers comprise a woven fabric scrim, the weave incorporating tunnels at least some of which contain the heating wire or heating element.

10. A duvet according to any one of claims 5 to 9 in which the layer or layers of flexible material forming the heatable panel are a light weight fabric material.

11. A duvet according to any one of the preceding claims including control means for controlling the amount of electrical power supplied to the heatable panel.

12. A duvet according to claim 11 in which the heatable panel is supplied with alternating current, and the control means is operable to select nonrectified or half-wave rectified wave forms.

13. A duvet according to claim 11 in which the heatable panel control means incorporates one or more thyristors for controlling the current passed from the supply to the heatable panel.

14. A duvet according to claim 11 in which the heatable panel control means incorporates one or more triacs for controlling the current passed from the supply to the heatable panel.

15. A duvet according to any one of claims 5 to 14 in which there are at least two heating wire or heating element runs between each pair of rows of stitches or welds holding together the layers of thermally insulating padding and the heatable panel.

16. A duvet according to any one of claims 6 to 15, in which the distance between adjacent heater wire element tunnels is at least 5 cm and the pitch distance between stitches securing together the layers of thermally insulating padding and the electrically heatable panel is at least 15 cm.

17. A duvet substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

18. A duvet substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.