COVERS FOR USE IN SLEEP

Abstract: A cover for use in sleep for example a duvet has means for adjusting or varying the thermal insulation provided by the cover. In one arrangement a series of areas (12) are defined by sewing lines (11) and within the areas are a number of spaced fixed insulation elements (14) and other insulation elements (18) which are movable by external pull straps (20) into and out of spaces (16) between elements (14) to vary the overall insulation of the cover (10). In other arrangements parallel separate insulating bags extend lengthwise of the cover on a support sheet and can be adjusted sideways to provide gaps. In other arrangements the insulation in separate bags is deformable using external pull straps which can be coloured to indicate the extent of adjustment. The invention can be applied to sleeping bags.

Description: COVERS POR USE IN SLEEP This invention relates to covers for use in sleep. In recent years bed covers in the form of conti¬ nental quilts or duvets have tended to replace blankets to provide the necessary thermal insulation or domestic beds. Duvets have high thermal insulation properties and usually consist of a soft insulating filling material contained within a fabric bag of relatively low thermal resistance. Such covers are available with specific insula¬ tion values - lower values being suitable for summer use and higher values for winter use, each duvet having only one insulation value. It is possible to use two duvets with suitable attachments to enable one to fully overlie the other, but this is inconvenient. According to this invention a cover for use in sleep comprises thermal insulation characterized by means for adjusting the thermal insulation provided by the cover. With this arrangement the insulation provided by the cover can be adjusted. There may be means for adjusting the relative insulation provided by different regions of the cover. The adjustment may be progressive. The insulation may comprise a plurality of separ¬ ate insulator elements movable relative to each other. There may be a support membrane for the elements. There may be one or more fixed insulator elements. In one arrangemen the fixed elements are spaced, and the movable elements are movable to vary the extent which they overlap the spaces. There may be means operable exterior to the ele¬ ments for effecting the relative movement. The operable means may comprise a common means operable to move a plurality of elements. There may be means operable to move the elements apart and separate means operable to move the elements together. The operable means may comprise manually operable pull devices. The insulation may comprise a plurality of insul¬ ator units extending lengthwise of the cover, each unit containing the insulator elements. The elements may form two layers and means for holding the layers in selected positions of relative adjustment. In one form of construction the insulation com¬ prises a plurality of separate insulator elements, and means for deforming the elements. The elements may be defor able laterally. There may be means for indicating the extent of adjustment. The invention may be applied to a bed cover in the form of a continental quilt or duvet, or to a sleeping bag. The invention may be performed in various ways and some specific embodiments with possible modifications will now be described by way of example with reference to the accompanying drawings, in which; Figs. 1 to 3 are sections illustrating' insulators; Fig. 4 is a plan view of a bed cover; Fig. 5 is a section on the line 5-5 of Fig. 4; Fig. 6 is a section of cover in a different condition; Fig. 7 is a view similar to Fig. 6 of a modification; Fig. 8 is a plan view of another cover; Fig. 9 is a section on the line 9-9 of Fig. 8; Fig. 10 is similar to Fig. 9 with the cover adjusted; Fig. 11 shows a modification; Fig. 12 is a schematic plan view of another arrangement ; Fig. 13 illustrates a section of Fig. 12; Fig. 14 is a plan view of a further cover; Fig. 15 is a plan view of another cover; and Figs.16,17 are sections of different arrangements . Referring to Figs. 1 to 7, Fig. 1 represents a section through an insulator of constant thickness t and uniform thermal resistance through its thickness. It can be shown that if the insulation is redistributed to create variations in the thickness t then the average insulation value of ' this new configuration will be less than that for the uniform case. By progressively increasing the extent of thickness non-uniformity a corresponding reduction in insulation value will result as shown in Figs. 1,2 and 3. Figs. 4 and 5 show a possible duvet configuration with facilities for adjusting the insulation either uniformly or selectively. This example shows an outer low thermal insulation containment bag 10 sewn along lines 11 into a series of parallel closed guide channels or regions 12. Located within each channel 12 is a regular sequence of fixed equispaced insulator segments or elements 14 (unshaded) connected by flexible straps 15 and separated by gaps 16 typically equal to the length of a segment 14. Also within each channel 12 is situated a row of movable insulator segments or elements 18 (shaded) with the same separations as the corresponding fixed segments 14. These movable segments 18 are connected end to end by a continuous flexible strap 20 (shown broken line) which emerges through, dedicated exit ports 22 and 24 in the cover 10 at the opposite ends of each channel 12. Only one strap 20 is shown in Fig. « The channels 12 normally extend lengthwise in the direction from head to foot but could extend laterally across the duvet and bed. The bag 10 is shown spaced from elements 14,18 for clarity but in practice would be a fairly close fit around the insulating elements to resist unwanted adjustment but permit desired adjustment. Under maximum insulation conditions these movable segments 18 completely fill the gap ' s 16 formed by the corresponding fixed segments 14. A gentle pull on the emergent connecting strap 20 will cause each movable segment 18 in the corresponding channel 12 to ride over its fixed neighbour in the direction of pull as shown in Fig. 6. This will generate a row of voids 23 each of which will increase in size with the displacement of the appropriate connecting strap 20. These voids 23 represent regions of low thermal resistance creating an overall reduction in the insulation of the appropriate channel 12. The magnitude of this reduction will increase with the size of void and hence with the displacement of the connecting strap. By applying an equal displacement to each strap 20 a proportional overall change in insulation over the area of the duvet will result. Changes in insulation in the opposite sense may be achieved by displacing the connecting straps in the opposite direction by pulling their other ends. If required non-uniform insulation values across the width of the duvet may be produced by selective displacement of the relevant connecting straps 20. This may prove useful for a double bed duvet if the insulation requirements of the occupants are different. The edge containing ports 24 may be the foot end. Different insulation values in a direction parallel to the length of channel 12 may be generated by displacement of a limited number of adjacent movable segments 18 within each channel. For example it may prove desirable to provide a higher insulation in the top (head) half of the duvet than the bottom (foot) half. This selective change in insulation over the duvet length may be achieved by attaching a second set of straps 28 Fig. 7 to the edges 30 of those corresponding movable segments 26 defining the separation of the selected different insulation regions. These straps 28 pass directly to and emerge through the exit ports 22 opposite their attachment edge 30. Connected movable segments 18 and 26 on the right hand side of this edge 30 will be displaced in the direction of a tensile force induced in the strap 28 creating a reduced insulation in the corresponding area of duvet ( to the right of the edge 30). The selected insulation value whether uniform or differential may be deduced from the lengths of straps external to the bag 10; these lengths being conveniently estimated from an appropriate colour coding of the straps. For example successive portions of strap may have different colours. The insulating elements 14,18 may for example be of fibre, plastics or feathers in a wrapping, for example a cloth wrapping. It has been indicated above that if the insulation in an insulating cover, e.g. a duvet, is distributed evenly over the area of the cover, then the mean insulation of the cover has a greater value. If the insulation is re-distributed to become non- uniform over the area then the mean insulation of the duvet will be less than for the uniform case. Open gaps or voids will yield the lowest insulation conditions. These voids have a dominant effect on the average thermal insulation of the duvet since heat flow through the duvet in response to a temperature difference across its thickness will concentrate in these voided zones. Any changes in the void fraction, i.e. the area of void as a fraction of the overall duvet area, will have a much greater effect on the mean insulation of the duvet than changes in the properties of the high insulation zones e.g. thermal insulation and density. It is possible therefore to induce small changes in void fraction and generate large changes in the mean insulation value of the duvet. Methods of inducing controlled changes in void fraction and hence comprehensive or selective insulation value of a duvet by simple adjustments to movable insulation segments have been described above. Other examples of ways of producing in a controlled and convenient manner changes in the value of overall or selective insulation will be described below with reference to Figs. 8 to 17. All the methods to be described involve the use of a set of parallel elongated soft thermal insulation bags for extending along the length of the bed. These bags may conveniently be a fabric wrapper or cover filled with hollow fibre, or feathers in line with conventional duvet insulating materials. Lower insulation zones are created by causing adjacent insulation bags to be displaced bodily in a direction normal to their length, or to be deformed by a controlled amount. The resultant localised "cooler" zones produced by this operation could produce discomfort to the occupant(s) of the bed. To reduce or avoid this, one or two flexible fabric or other membranes or wrappings extending over the area of the bed and slightly beyond may be used. The thermal insulation of such a membrane or membranes will still be negligible compared to that of the bags and though not quite as efficient as open zones the bags would still have a dominant influence on the mean or overall insulation value or characteristic of the duvet. For example the membrane may lie under the adjustable insulation and could be a separate removable sheet or be secured to the insulation bags. The membrane could be a bag enclosing adjustable insulation. The membrane restricts convective flow and thus tends to reduce temperature variation under the membrane. Simple adjustments can be made to obtain either an overall or selective change in duvet insulation, according to the requirements of the bed occupant(s). For example in the case of a double or king sized duvet one side could be adjusted to provide lower insulation and the other, higher insulation, as required. In one arrangement Figs. 8 to 10, an odd number of parallel insulation bags 40 are located over a flat fabric membrane 41 forming a support sheet. Conveniently, the centre bag 42 is secured onto the support sheet 41 e.g. by sewing. Each bag 40 has a set of pairs of fabric loops 43 regularly spaced along the length of the bag, the corresponding positions being the same in separate bags. Light fabric straps 44 are fed through corresponding loops 43 and secured at their central 45 and outer 46 positions on the support sheet. This arrangement allows the bags to be manually displaced Fig. 10 in a controlled manner along the straps creating longitudinal voids 44 hence low insulation zones. This process involves displacing the laterally outer bags 45a outwards, but because of the dominant effect of the lower insulation zones (corresponding to the voids) on the average insulation of the duvet, only small changes in displacement of the outer bags 45a are necessary, hence the overall increase in duvet width can be small enough to be accommodated in a standard duvet cover if this were required or provided. In a modification of Fig.8, the sheet 41 is omitted and if desired the centre bag 42 is movable on cord 44 • The cords 44 and loops 43 are such that the bags 40, 42 do not undesirably slide on the cords. In another modification the loops 43 are omitted and the cords 44 extend through the bags. In practice voids may be produced by gently displacing individual bags by hand. Alternatively, equal void width changes between adjacent bags can be produced by connecting these bags to a set of common adjustment straps 47,49 Fig. 11 one set on each side of a fixed centre bag 42 Fig. 11. The strap 47 includes portion 48 connected to individual bags via a loop 50, on an adjacent bag. Tension in these adjustment straps 47 will produce equal displacements of all movable bags in the opposite direction to the strap displacement resulting in a reduction of void widths. To induce equal increases in the void widths, the outer bags 45a are displaced outwards. In practice, by using these adjustment straps 47, 48 it is unnecessary to employ sets of transverse guide straps 44 passing through fabric loops as in Figs. 9,10 or a fabric support sheet 41. If, however, a support sheet is employed in order to suppress "cooler" zones, individual decorative covers (not shown) for the bags can be used to improve overall appearance if a conventional duvet cover is not used. If the support sheet 41 is not used, an outer duvet cover would be desirable, for reasons of comfort, handling stability, appearance and hygiene. With this transverse insulation adjustment it is advantageous, but not necessary to employ a removable duvet cover with side access to facilitate adjustment. If a conventional duvet cover is used, adjustment of insulation gap width by means of base access can be achieved by means of a lacing arrangement 52 between adjacent bags, Fig. 12. In this example a series of smooth loops 53, typically of plastics, are sewn along the edges 4 of each bag 40 in corresponding positions on adjacent bags. An adjustment cord 55 for lacing is secured to one of the top (head) loops 50 on each of the adjacent bags and fed through the remaining sequence of loops as indicated in Fig. 12 before emerging from the base ends of the bags. If the exposed cord is displaced by the amount D by applying tension, then adjacent bags will be drawn together by an average amount D/N ' where N is the number of loops along the edge of the bag. Other lacing arrangements can be used. For example a second cord 54a (only one shown) can pass through loops 53 as shown dotted so that a more symmetrical adjusting force is applied to adjacent bags. To avoid the void widths changing due to induced stresses in the lacing cords arising from movement of a user during sleep, adjustable sliding cord stops or toggles 57 can be employed. When pushed against the exit loop 58 and locked into this position no further opening of the appropriate void can occur. In practice, the laced bag arrangement would, for reasons of comfort, appearance and stability be fitted into a conventional duvet cover 59 Fig. 13 with a base access and with outer bags overhanging the side of the bed 60. This would create a light tension in the connecting cords opposing gap reduction under human-induced stresses. The number of bags and the insulating system geometry would normally be chosen such that the laced bag configuration corresponding to the lowest inβulation condition (maximum void width) would allow containment in a standard duvet cover, probably with the laterally outer overhanging bags in compressive contact with each other. It has been indicated above how voids can be made narrower by applying tension to the appropriate adjustment cord. In order to produce void openings to reduce insulation, the cord stops 57 are displaced an appropriate amount along the emergent adjustment cord 55 and locked in this position creating a free length of cord 61. By gently pulling the side edges of the duvet cover, or lightly shaking it, this free length will be taken up into the laced region between adjacent bags creating a proportional increase in void width. Since individual voids can be adjusted it is easy to produce different insulation values on either side of the duvet to suit the requirement of the bed occupants. To facilitate control and the ability to reproduce insulation values, appropriate colour coding of the cords can be implemented, as above. If it is desired to produce selective insulation values along the length of the bed, for example to provide higher insulation at the head end and lower insulation at the foot end, or vice-versa, then the single adjustment cords described can be replaced by two sets, one providing adjustment to the 'upper half and the other to the lower half, both cords emerging from the foot end of the bed. To improve comfort and enhance mechanical handling stability, additional transverse fixed insulation bags, extending the full width of the duvet, for example as shown dotted at 93 Fig. 12 can be secured to the upper (head) and lower (foot) ends of the bags forming a high insulation stationary border. The bags 93 would be stitched continuously across the ends of the bags 40 when these are in the closed - together position. This arrangement does not signif cantly impede gap adjustment since the bags will readily deform despite being secured at each end. Fixed insulation bags can be provided at the head and/or foot in the other arrangements described herein and possibly also at the sides being secured to a membrane where not secured to the movable bags. In circumstances where the bed occupant (s) require very low insulation but also the comfort of some weight in a cover it may prove appropriate to dispense with any membranes in the form of a support sheet or duvet cover. In this case any local discomfort created by exposed straps connecting adjacent insulating bags could be avoided by providing soft padding of the straps. Alternatively the straps could be isolated from the occupant (s) by connecting adjacent insulation bags to a continuous highly permeable flexible membrane e.g. net, situated beneath the straps. With reference to Fig.8 although adjustments are manual they are controllable for each insulation bag and if required can provide selective or uniform adjustment across the bed. Adjustments can be made to be stable under normal sleep conditions. Th'is ease of adjustment, controllability and stability has significant advantages. The methods described above involve displacing bags or elements bodily to generate lower insulation voids. An alternative procedure to produce such voids is to deform the bags in a controlled manner. In the arrangement of Fig. 14 there is a support sheet 62. Individual bags 40 are laid side by side from head to foot with adjacent edges in contact. The bags are stitched at 63 onto the support sheet along corresponding edges, except the centre bag which is stitched down the middle at 64. The other edges 65 are free to move. Attached to corresponding points on the free edges 65 are a series of adjustment straps 66 for right hand side and 67 for left hand side. Each strap from the centre bag passes under the appropriate set of bags under suitable access ports (not shown) in the stitching before emerging at the outer edge of the duvet. Tension on the straps will deform the connected bags in the direction of pull to an extent dependant upon the strap displacement. In this way selective (along the length of the bags) or overall controlled production of lower insulation zones corresponding to the exposed regions of the support sheet can readily be obtained. To reduce gaps, strap tension is removed and the bags patted or the duvet gently shaken. The individual adjustments can be limited by means of a suitable lockable sliding stop or toggle 68, on each strap. Lines 65a indicate an adjustment position for edges 65. In the arrangement of Fig. 15 a set of edge- contacting insulation bags 70 is again employed but these are stitched onto a support 71 along their mid- line positions 72. Adjustments are made from the foot end of the duvet. In this case low insulation or void zones are created in each bag independently of the others in the set. This is achieved by securing two cords or tapes 73 and 74 to opposite sides 75 and 76 at the head end of each bag and wrapping each pair around the respective bag in opposite directions through edge stitched loops 77 to form two helices of opposite sign. The pair of cords emerge from the foot of the duvet where they are secured together as a common cord 78. For reasons of clarity this helical cord arrangement has only been shown on one bag. Controlled deformations of individual bags are obtained by applying tension to the emerging cords. This will reduce helical cord lengths, creating an increase in the area of the low insulation zone associated with each bag. The selected bag adjustment is secured by using a lockable sliding toggle 79 which defines the emergent length of the adjustment cord. Reduced areas of low insulation zone may be produced by sliding the toggle back along the adjustment cord providing a free length of cord 80 between the toggle and the foot of the duvet. Gently patting the appropriate insulator segments will release any remaining tension in the helical cords and allow the insulator to return in part, or totally, to the undeformed state according to the adjustment on the control cord. In the arrangement of Figs. 16,17 insulation changes do not require adjustment within individual bags. Two support sheets 90, 91are employed each possessing an identical set of insulation secured there to with separations typically equal to the bag width. The two support sheets are ove-rlaid with their respective bags parallel. If relative displacement of the bags is manually produced in a direction normal to their length by separating and then re-connecting the two sheets then different mean insulation values of the arrangement may be produced. For example, if the bags 84 Fig. 16 on the contacting support sheets coincide, then the associated low insulation zones 85 will also coincide, providing a relatively low insulation area and a consequent minimum insulation condition for the duvet. If high and low insulation zones are caused to coincide 86 in Fig. 17 then a state of maximum insulation will result. Conveniently the two support sheets may be formed from a single sheet resulting in a flattened tubular configuration. Any adjustments to the degree of overlap of corresponding bags can be stabilized using for example suitable fasteners or orthogonal strips 87 of hook and eye fasteners such as that sold under the trademark VELCRO along the edges of the support covers. It may also be necessary to fix suitable fasteners 88 or 'Velcro 1 to stabilizing cords 92 at the central regions of the duvet to prevent possible mis-alignment during sleep following human body movement. The fasteners 88 can be adjusted along the cords 92 to hold the sheets in the desired position of overlap. The creation of low insulation zones can have a dominant effect on the overall insulation value of a duvet. This will minimise the influence of any changes in the properties of high insulation regions, e.g. an increase in their thickness or density which will have a relatively small effect on the overall insulation value of the duvet. Various ways of inducing changes in the lower insulation areas to produce corresponding changes in overall or selective insulation have been desrcibed. One way involves moving bodily one or more parallel insulating bags to generate voids or gaps between adjacent bags, either by hand or using suitable cord or tape adjusters. The second involves inducing controlled deformation of individual or sets of parallel insulating bags in response to the displacement of adjustment cords or straps. To avoid cold zones which could lead to discomfort, either a single support sheet or conventional duvet cover can be applied. Methods appropriate to full size double or king sized duvets have been described but all the arrangements are applicable to single or even cot sized duvets. Conventional domestic bed covers-duvets-are limited in their versatility in the they are unable to provide a continuously variable range of insulation values in response to prevailing temperature conditions and user requirements. The duvet configuration described have simple adjustments to provide continuous uniform or selective changes in insulation value over the area of the duvet. The arrangements involve no addition or removal of insulation to or from the duvet. In ig. 14, instead of deforming the insulating material sideways to vary the void or lower insulation area, the material may be deformed downwards; for example an upper central part of a bag can be arranged to be pulled downwards by pulling on straps 67. Thus instead of creating complete void zones e.g. gaps or thin membrane low insulation zones, it is possible to use thicker low insulation zones. In this case the mean thickness of the duvet could be progress- ively reduced using a lacing arrangement through its thickness drawing the top and bottom surfaces towards each other when tension is produced in the laces. This could be over the whole area or at spaced regions. To improve the efficiency of this arrangement the upper surface of the duvet may be provided with additional strips of fabric stiffer than the existing containment fabric; this will tend to spread the load imposed and generate a greater mean reduction in thickness for a given cord tension and hence increase the range of possible insulation adjustments. Where desired, adjustment or variation of the insulation can be in response to changing temperature conditions. Por example as shown dotted in Pig. 14 a temperature sensor 100 can be connected to an electric motor 101 to energize the motor 101 to pull on cords 67 if the sensed temperature exceeds a predetermined limit which could be adjustable. This may have application for cot covers or medical use. The invention is not restricted to duvets but can be applied also to sleeping bags, or example the invention can be applied to the upper part or the whole of a sleeping bag and the term bed cover is to be understood as including sleeping bags. Preferably in Pig. 12 the edges of adjacent bags at their ends at 51 abut or are secured together as well as being secured to bags 93. The deformability of the bags permits the adjustment or variation of void width.

Claims: C AIMS 1. A cover for use in sleep comprising thermal insulation characterized by means (14, 18, 20; 40, 42, 44; 40, 42, 47, 48; 40, 52, 53; 40, 66; 70, 73, 74; 84, 90, 91) for adjusting the thermal insulation provided by the cover. 2. A cover as claimed in Claim 1, characterized by means (14, 18, 20; 40, 42, 44; 40, 42, 47, 48; 40, 52, 53; 40, 66; 70, 73, 74; 84, 90, 91) for adjusting the relative insulation provided by different regions of the cover. 3. A bed cover as claimed in Claim 1 or Claim 2, characterized in that the adjustment is progressive. 4. A cover as claimed in any preceding Claim, characterized in that the insulation comprises a plurality of separate insulator elements (18; 40; 70; 84) movable relative to each other. 5. A cover as claimed in Claim 4, characterized by a support membrane (41; 62; 71; 90, 91) for the insulator elements. 6. A cover as claimed in Claim 4 or Claim 5, characterized in that the insulation comprises one or more fixed insulator elements (14; 42). 7. A cover as claimed in Claim 6, characterized in that the fixed elements are spaced, and the movable elements are movable to vary the extent which they overlap the spaces. 8. A cover as claimed in any of claims 5 to 7, characterized by means (20; 28; 47, 48, 49, 52; 66; 73, 74) operable exterior to the elements for effect¬ ing the relative movement. 9. A cover as claimed in Claim 8, characterized in that the operable means comprises a common means operable to move a plurality of elements. 10. A cover as claimed in any of Claims 6 to 9, characterized by means (49) operable to move the elements apart and separate means (47, 48) operable to move the elements together. 11. A cover as claimed in any of claims 8 to 10, in which the operable means comprises manually operable pull devices. 12. A cover as claimed in any of claims 1 to 11, characterized in that the insulation comprises a plural¬ ity of insulator units extending lengthwise of the cover, each unit containing the insulator elements. 13. A cover as claimed in Claim 5, characterized in that the elements form two layers and means (87) for holding the layers in selected positions of relative adjustment. 14. A cover as claimed in any of Claims 1 to 4, characterized in that the insulation comprises a plural- ity of separate insulator elements (40; 70), and means (66; 73, 74) for deforming the elements. 15. A cover as claimed in Claim 14, in which the elements are defor able laterally. 16. A cover as claimed in Claim 14 or Claim 15, including manually operable pull devices (66; 73» 74) extending exterior of the elements for effecting the deformation. 17. A cover as claimed in Claim 16, characterized in that the insulation comprises a plurality of elements for extending in the direction of foot to head, and means (66; 73, 74) for deforming the elements at a plurality of locations spaced in the direction. 18. A cover as claimed in Claim 17, characterized in that the deforming means are individually operable. 19. A cover as claimed in any preceding claim, including means for indicating the extent of adjuslznent. 20. cover as claimed in any preceding Claim, in the form of a continental quilt or duvet. 21. cover as claimed in any of Claims 1 to 19, in the form of a sleeping bag.

Inventors: FOTHERGILL IAN ROBERT, FOTHERGILL, IAN, ROBERT
Applicants: FOTHERGILL IAN ROBERT, FOTHERGILL, IAN, ROBERT
Application year: 1992
Main classification: A47G9
IPC codes: A47G9