Abstract:
A duvet cover comprised of a pouch which is dimensioned to receive therein a flat down insulating sheet. The pouch has an opening for the insertion and removal of the down insulating sheet whenever the pouch needs to be cleaned. Accordingly, the down insulating sheet is not subjected to washing or dry tumbling which is damaging to the down insulating sheet. Attachments are secured inside the pouch and along peripheral edges of the down insulating sheet whereby the down insulating sheet is secured in position inside the pouch and does not shift, although it is in close fit therein. Such duvet cover has a uniform flat appearance and has a prolonged life.

Description:
[0001]    This is a continuation in part of application Ser. No. 14/998,927 filed on Mar. 7, 2016 and relating to a duvet cover constructed of a down feather sheet. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to duvet covers and more particularly to a duvet cover having a pouch having attachments inside to removably retain a flat down thermally insulating sheet of substantially constant thermal efficiency, or fill power and which is removed from the pouch when it is necessary to wash the pouch to prevent the down insulating sheet from being washed and tumbled dried. 
       BACKGROUND OF THE INVENTION 
       [0003]    Duvet covers having down insulation trapped between the base sheet and top sheet of the duvet cover are well known in the art. It is also well known that down feathers provide excellent insulating properties. The higher the fill power (fluffiness) of the down and therefore the more air trapped in the down, the more insulating ability an ounce of the down will have. Down is also a very light product that is desirable for insulation and particularly with products wherein weight is a factor, such as articles of apparel, sleeping bags, duvet covers, etc. However, down is a difficult product to work with due to its fluffy nature and unstable condition. It can also be hazardous to one&#39;s health has its fluffy miniscule filaments easily propagate into the surrounding air. For this reason work personnel are advised to wear breathing masks. 
         [0004]    Articles of apparel and bedding manufactured with down feather insulation are constructed by entrapping the down between opposed fabric sheets. To prevent the down from displacement, the fabric sheets are sewn with quilt stitched patterns. Some of these patterns are produced by cross-stitches to form small pockets in which the down feathers are trapped. See U.S. Pat. No. 5,692,245 as an example. With bedding products, such as a duvet cover, the quilt stitches may be spaced apart from about 1 inch to 10 inches forming pockets with loose down therein. During use of these products, the down shifts within the pockets and form areas where the down is concentrated and other areas where there is much less down or no down. This results in areas where there is too much insulation or not enough insulation. Furthermore, because the down is loose between the fabric sheets at the time of stitching, the down is not uniformly distributed between the fabric sheets resulting in stitching being done over heavy down underlay or no down at all creating irregularities in the stitched seams which are visible to the eye or resulting in a rejection of the manufactured product. Because duvet covers are made with large cross stitched quilt patterns and consequently large pockets for retaining the down, the down will propagate to corners of these pocket and unevenly therein. In the case of duvet covers having no quilt stitches, the down always propagate into regions and it is then necessary to shake the duvet in an attempt to distribute the down substantially evenly therein but such is near to impossible. Accordingly, the duvet cover has to be shaken constantly due to the unstable nature of the down. 
         [0005]    A further problem with duvet covers is that when they are washed, the loose feathers or down absorbs water and the mechanical action of a drying machine is not desirable for the down as the duvet cover is subjected to a tumbling and stretching action. Therefore, it is best to let the duvet cover dry in the open air to maintain a duvet cover with a uniform appearance. Dry cleaning is an option which is more costly and also is not desirable down duvet covers. Accordingly, the useful life of the duvet cover is reduced when subjected to washing and drying 
         [0006]    There is also a need to have a duvet cover wherein the thermal insulation factor can be modified throughout the duvet cover or in designated parts thereof to suit individual preferences and/or calibrate the insulation of the duvet cover to the cnhanging seasons. 
         [0007]    U.S. Pat. No. 6,025,041 addresses the problem of using the loose fluffy down feathers in the manufacture of articles and relates to a method of forming a down feather sheet of substantially constant thickness and particularly for use in the fabrication of articles of apparel such as described in U.S. Pat. No. 5,692,245. 
         [0008]    It is also desirable with duvet covers to provide different thermal properties for each sleeping side of a bed, as is described and demonstrated in US Patent Publication 2005/0268399. It is also well known that the body of a person, when sleeping, requires less covering and thermal insulation in certain sections of its body. 
         [0009]    It would also be desirable to manufacture light weight duvet covers having esthetically pleasing stitch patterns and designs without concern to the size of the spaces formed between the design pattern stitch seams where loose down feathers could be unstable or the complexity of the stitch patterns. 
       SUMMARY OF THE INVENTION 
       [0010]    It is a feature of the present invention to provide a duvet cover which substantially overcomes the above mentioned disadvantages of prior art duvet covers and provides the above mentioned needs. 
         [0011]    It is another feature of the present invention to provide a duvet cover comprised of a pouch having internal attachments for removably securing therein a down insulating sheet which can be removed for washing the pouch thereby prolonging the useful life of the down duvet cover 
         [0012]    Another feature of the present invention is to provide a duvet cover having all sorts of stitched design pattern wherein the propagation of down feathers in irregular pockets formed by the stitch seam patterns is not an issue. 
         [0013]    A further feature of the present invention is to provide a duvet cover wherein pockets are formed to accommodate down feather sheets having different insulation factors. 
         [0014]    A still further feature of the present invention is to provide a duvet cover having a down feather sheet secured inside the duvet cover and which can be disposed in a deployed or stored position. 
         [0015]    A further feature of the present invention is to provide a duvet cover wherein the insulating factor thereof can be modified in whole or in part thereof. 
         [0016]    According to the above features, from a broad aspect, the present invention provides a duvet cover which is comprised of a base sheet and a top sheet interconnected together by stitched seams. A down feather sheet is retained between the base sheet and the top sheet. The down feather sheet has a substantially constant density of down feathers with the down feathers being retained captive by a binder. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0017]    A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
           [0018]      FIG. 1  a perspective view of a duvet cover constructed in accordance with the present invention and wherein a decorative stitched design pattern is formed in a section of the duvet cover; 
           [0019]      FIG. 2A  is a cross-section view of a down feather sheet comprised of down feathers held together by binder fibers and adhered on a backing sheet; 
           [0020]      FIG. 2B  is a cross-section view, similar to  FIG. 2A , but wherein the down feathers are held between opposed sheets; 
           [0021]      FIG. 3  is a plan view of a duvet cover wherein a down feather sheet is held captive between the base and top sheets of the duvet and a peripheral stitch seam; 
           [0022]      FIG. 4A  is a plan view of a duvet cover constructed in accordance with the prior art; 
           [0023]      FIG. 4B  is a partial cross-section view of prior art  FIG. 4A  showing the distribution of down feathers in the pockets; 
           [0024]      FIG. 5A  is a plan view of a duvet cover having large transverse pockets to retains down feather sheets having different thermal insulation factors; 
           [0025]      FIG. 5B  is a cross-section view, not to scale, of  FIG. 5A ; 
           [0026]      FIG. 5C  is a fragmented perspective view illustrating a stitched design pattern comprised of compressed stitched areas of different size and stitch line spacings; 
           [0027]      FIG. 6A  is a plan view of a duvet cover which is segmented into two half sections with the sections provided with a down feather sheet having different thermal insulation factors and wherein an irregular stitched design pattern is formed in the top sheet of the sections; 
           [0028]      FIG. 6B  is a cross-section view, not to scale, of  FIG. 6A ; 
           [0029]      FIG. 7  is a fragmented perspective view of a duvet cover wherein the down feather sheet is rolled to a bottom of the duvet cover, such as to remove the insulation factor of for ease of storage of the duvet cover; 
           [0030]      FIG. 8  is a fragmented cross-sectional view illustrating the rolled-up down feather sheet held captive in a pouch formed along the bottom edge inside the duvet cover; 
           [0031]      FIG. 9  is a plan view of the duvet cover formed of two independent longitudinal sections with each section formed in three transverse sections each having a double layer down feather sheet with the top layer being adapted to be rolled upn itself along a side edge of the duvet cover; 
           [0032]      FIG. 10  is a cross-sectional side view of the double layer down feather sheet; 
           [0033]      FIG. 11  is a plan view of a duvet cover with a single double down feather sheet with the top down layer rolled to a side and retain in a manner as shown in  FIG. 12 ; 
           [0034]      FIG. 12  is an enlarged fragmented cross-sectional view illustrating the top layer of the down sheet rolled on itself and retained by a holding flap; 
           [0035]      FIG. 13  is a perspective view, partly fragmented, illustrating another embodiment of the duvet cover and wherein it is comprised of a pouch having attachments inside the pouch to removably retain therein a down insulating sheet; 
           [0036]      FIG. 14  is a perspective view of the down insulating sheet adapted to be removable secured inside the pouch illustrated in  FIG. 13 ; 
           [0037]      FIG. 15  is a fragmented cross-section view of the down insulating sheet showing the securement of an attachment tab; 
           [0038]      FIG. 16  is an exploded fragmented cross-section view showing a tab of the down insulating sheet and a tab of the pouch being interconnected together by means of a button closure attachment, 
           [0039]      FIG. 17  is a fragmented cross-section view showing a tab wherein the attachment is provided by Velcro connectors, and 
           [0040]      FIGS. 18A and 18B  are end cross-section views illustrating a duvet cover comprised of a pouch in which two down insulation sheets are removably attached one on top of the other to modify the thermal insulation factor of the duvet cover and wherein one of the down insulation sheet may be smaller to suit the insulation need in a section only of the duvet cover 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0041]    Referring now to the drawings, and more particularly to  FIGS. 1 to 3 , there is shown a duvet cover  10  constructed in accordance with the present invention and disposed on a bed  11 . The duvet cover  10  is formed by a base sheet  12  and a top sheet  13  and a down feather sheet  14  disposed there between and interconnected together by stitched seams  15  or  16  or both. As shown in  FIG. 3 , stitched seams  15  are formed along the peripheral edges  16  of the duvet cover  10  to interconnect the base sheet  12  and the top sheet  13  and which forms a pocket in which the down feather sheet  14  is immovably trapped there between or sewn captive along one or more of the stitched seams  15 . As shown in  FIG. 1  the down feather sheet  14 , trapped between the base sheet  12  and the top sheet  13 , is additionally secured by irregularly disposed design pattern stitched seams  16  to give an esthetically pleasing appearance to the duvet cover without concern to the large areas or pockets, such as areas  17 , formed between stitch seams  16  spaced far apart as the down is held captive in the down feather sheet  14  and does not propagate. The stitch seams  16  extend through the top sheet  13 , the down feather sheet  14  and the base sheet  12 . Accordingly, the down feathers are not displaced when the duvet cover is manipulated during use. Also, the down feather sheet  14  provides a duvet cover with substantially uniform thermal insulating density throughout as well as uniform thickness. 
         [0042]    With reference to  FIGS. 2A and 2B , the down feather sheet  14  is comprised of loose down feathers  18  mixed with a binder herein polyethylene fibers  19  or a powder adhesive binder and deposited on a support backing sheet  20  where it is caused to bind by the application of heat to form a homogeneous down feather sheet.  FIG. 2B  shows another embodiment of the down feather sheet where the down is trapped and bound together and between opposed cover sheets  20  and  20 ′. The down feather sheet  14  may also be formed as disclosed in my above mentioned U.S. Pat. No. 6,025,041 where the down feathers are bound together to form a homogeneous sheet without the use of support fiber sheets wherein the down sheet is of very light weight. 
         [0043]    As shown in  FIG. 3 , a slit opening  21  may be formed adjacent an edge of the duvet cover, herein the top edge to remove the down feather sheet  14  when washing the duvet cover. A fabric slit cover flap  22  is formed by an over-turned edge portion of the base sheet  12  or the flap may be formed by a different fabric piece sewn on a top edge section of the duvet cover to conceal the slit. 
         [0044]      FIGS. 4A and 4B  illustrate some of the above mentioned prior art quilt pattern stitch seam designs formed in duvet cover to maintain the loose down feathers between the base sheet  25  and the top sheet  26 . As shown in  FIG. 4A , the quilt pattern stitch seams  24  produces small square pockets  27  into which down is held captive. However, the close spacing of the stitch seams makes it impossible to achieve a high loft in the down feathers trapped in these small pockets  27  and therefore limiting the insulation factor of the down in the duvet cover. As shown in  FIG. 4B , when larger pockets  27  are formed by spacing the stitch seam lines  24  further apart, the loose down feathers  28  in the larger pockets  27  are unstable, and as herein shown the down propagates unevenly in these large pockets to form down clusters  29  where the insulation factor is high, and areas  30  where there is very little or no down and wherein the insulation factor is very low. This creates a duvet cover with cold spots created by irregular distribution of the down and accordingly irregular thermal insulation. These prior art disadvantages are obviated by the duvet cover  10  manufactured according to the present invention. 
         [0045]    It is also desirable to also produce a duvet cover wherein a specific section or sections of the duvet cover has a different thermal insulating factor to form areas which are cooler on specific sections of the body of a user person. This is achievable with the present invention by different duvet designs formed by pattern stitch seams. Some of such designs are illustrated by  FIGS. 5A to 5C . As shown in  FIGS. 5A and 5B , the duvet cover  10 ′ is formed with three large transverse pocket sections  30 ,  30 ′ and  30 ″ in which there is retained a down feather sheet, with one or all of the sheets having a different thermal insulating factors or density. In the embodiment illustrated, the pocket section  30 ′ has an insulating factor inferior to the other two pocket sections  30  and  30 ″ to provide less insulation or warmth in the lower torso section of a person&#39;s body which is favorable to a person&#39;s health when asleep. The pocket sections are defined by transverse seam lines  31  extending across the duvet cover  10 ′. Slits  32  may be formed at the end of each pocket sections for insertion and removal of the down feather sheets. Each slit  32  is concealed by a flap  33  formed as previously described. 
         [0046]      FIGS. 6A and 6B  illustrate a further duvet cover  10 ″ wherein the duvet cover is sectioned longitudinally by a central stitch seam  34  to form two half pocket sections  35  and  35 ′ to receive therein a down feather sheet having different thermal insulating factors wherein a person sleeping on one side of the bed receives less warmth from the duvet cover  10 ″ than the person sleeping on the other side to suit the desire of the user persons. Again the down feather sheet is inserted and removed from these two sections through associated slits  36  and  36 ′ formed along an edge of the duvet cover and concealed by respective flaps  37  and  37 ′. If the down feather sheet is meant to be a fixed and non-removable part of the duvet cover  10 ″, design stitch seams  38  may be formed in the duvet cover. 
         [0047]      FIG. 5C  illustrates a still further embodiment of the duvet cover of  FIG. 5A , wherein the sections  30 ,  30 ′ and  30 ″ do not contain a removable down feather sheet but a permanent down feather sheet and wherein the loft of the down feathers in their sections is modified by applying design stitch seam patterns formed by stitching. As shown the central transverse section  30 ′ has a design pattern throughout with design portions in the pattern having close stitch lines, such as portion  40 , to compress the down feathers in that section thereby reducing the loft of the down and the air trapped therein to provide down compressed zones of less thermal insulating efficiency. Other design portions are formed as small square portions  41  wherein the down is less compressed than in the portion  40  but more compressed than in the adjacent section  30  whereby to form a band or section  30 ′ having an overall reduced thermal insulation efficiency than the adjacent sections  30  and  30 ″ to achieve the same result as the embodiment illustrated in  FIG. 5A  while providing an esthetic patch design feature in a large band extending across the duvet cover  10 ′. Because the down feathers are not loosely retained between the base sheet  12  and the top sheet  13  all sorts of stitch designs can be made without the concern of forming cold spots in the duvet cover due to loose down insulation. 
         [0048]    With reference now to  FIGS. 7 and 8  there is shown another embodiment of the duvet cover  10  of a type such as illustrated in  FIG. 3  wherein the down feather sheet  14  has a bottom edge section  14 ′ held captive by the peripheral seam  15 ′ formed in the lower edge of the duvet cover. The slit opening  21  provides access to the down feather sheet  14  to permit the down feather sheet to be rolled-up between the base sheet  12  and the top sheet  13  and stored in the bottom end of the duvet cover when not required during warmer weather periods. Still further a storage pouch  45  may be formed and attached in the lower peripheral seam  15 ′ to retained the down feather sheet roll captive therein. The pouch can be held closed by a zipper fastener or Velcro (Registered Trademark) fastener  46  as herein illustrated. The down feather sheet is made easily accessible by turning the base sheet and top sheet inside-out through the slit  21 . 
         [0049]    Referring now to  FIGS. 9 to 12  there is illustrated another embodiment of the present invention wherein the duvet cover  10 ′″ is a two-sided duvet cover, a first side  50  and an adjacent second side  51 , such as for use on a king size bed. Each side  50  and  51  is divided into three transverse sections,  50 ′,  50 ″ and  50 ′″ for the first side and  51 ′,  51 ′ and  51 ″′ for the adjacent section  51 . In each of these sections the is secured a double layer down feather sheet  52 , as illustrated in  FIG. 10 . 
         [0050]    The bottom layer  53  of the double layer down feather sheet is secured to the base sheet  12  of the duvet cover adjacent a central longitudinal seam  56  by a snap attachment  55  or other suitable fastener or attachment The top layer  54  of the double layer down feather sheet  52  is detachably secured to the bottom layer  53  above the attachment  55  also by a snap attachment  56  or other suitable connection. Each down sheet layer  53  and  54  may have, for example,  50  grams/square meter of down feathers from goose or duck. Accordingly, the double layer sheet when folded provides insulation in the order of  100  grams/square meter. If the top layer  54  is rolled upon itself along the edge of the duvet cover the insulating factor in any of the transverse sections can be reduced by half. Accordingly, the user person can adapt its side of the duvet cover for its personal comfort. 
         [0051]    As shown in  FIG. 11  the top layer  54  has been rolled-up in a tight roll  60  along the edge  61  of the duvet cover and is retained in that position by one or more retaining flaps  57  sewn to the inside face of the top sheet  13  of the duvet cover  10 ′″. A Velcro (registered trademark) connector  58  is secured to the retaining flap  57  and to another like matting connector  59  secured to a predetermined location on the bottom down feather sheet  53 . Accordingly, the roll  60  is retained firmly in place. Every one of the transverse sections can be adjusted to suit the preference of each user person. 
         [0052]      FIG. 12  shows a duvet cover  10  having a double layer down feather sheet which can form a roll  65  of its top layer for storage along a side edge of the duvet cover. 
         [0053]    It is conceivable that the double layer down feather sheet can also be used in articles of apparel where the top sheet can be rolled to a concealing location and held in a pouch form with the article of apparel. Still, other applications of the double layer down feather sheet are conceivable. 
         [0054]    With reference now to  FIGS. 13 to 17  there will be described another embodiment of the duvet cover wherein it is formed by a pouch  70 , herein shown of rectangular shape and having an opening  71  along a longitudinal edge  72  thereof to receive therein a down insulating sheet  73 , as shown in  FIG. 14 . The opening  71  has a closure, such as a zipper  76  or buttons or other suitable closures. Anchoring elements or attachments  74  in the form of tabs are provided at convenient locations inside the pouch  70  and secured along the inner opposed parallel peripheral edges  75  of the pouch. As herein shown, these attachments  74  are disposed in the corners of the pouch and about mid-way along the opposed parallel side edges  72  of the pouch. Likewise, the down insulating sheet  73  is also of rectangular shape and dimensioned for close fit inside the pouch and also provided with attachments  77  disposed along its opposed parallel edges at complimentary locations to the tabs  74  of the pouch. 
         [0055]    To the tabs  74  and  77  there is secured complimentary connectors, and has herein illustrated in  FIGS. 13 and 14 , in the form of buttons  78  and button slots  79 . In order to insert and secure the down insulating sheet  73  inside the pouch  70 , the pouch is pulled out through the opening  71  exposing the tabs  74  along the rear side edge  72 ′ and attaching the tabs  77 ′ along one of the side edges of the down insulating sheet thereto by the use of the buttons  78 . The tabs at the end edges  72 ″ can then be attached followed by the tabs at the edge  72  adjacent the opening. The tabs  74  and  77  may not be necessary to retain the down insulating sheet taunt inside the pouch depending on the size of the duvet cover. More attachment tabs may be provided if necessary. 
         [0056]    The insulating down sheet  73  herein shown is comprised of a uniform flat down material layer  80  as shown in  FIG. 15 , which is mixed with one or more binders  81  in the form of binding fibers and glue particles mixed together and held captive between opposed fabric sheets  82  and  83  by the binders mixed with the down. Such down insulating fabric sheets are described in my U.S. Pat. Nos. 6,025,041 and 9,380,893. Such a down insulating sheet is of constant thickness and has a constant thermal insulating factor for the reason that the down in the insulating sheet does not shift. By removably securing the down insulating sheet  73  in a pouch  70 , the pouch can be washed without having to wash the down insulating sheet which is removed. This assures that the down in the insulating sheet is not affected by washing and the tumbling and stretching action of a drying machine which can damage the insulating sheet causing clumping or tears therein thereby destroying the constant insulating factor of the duvet cover. Also, seeing that the down insulating sheet is of constant and uniform shape throughout, the duvet cover pouch has a uniform flat shape without the need, as in the prior art, of having the make quilt stitching throughout the duvet cover to stabilize the loose insulation therein, whether down, feathers, artificial insulation, etc. 
         [0057]    With reference to  FIGS. 16 and 17 , there is shown different types of connectors secured to the tabs. As shown in  FIG. 16  the tab  77  of the of the down insulating sheet  73  is secured along the edge of the sheet by stitches  85  and a button fastener  86  is secured to the tab  77  for snap connection with a complimentary cup fastener  87 , secured to the tab  74  of the pouch  70 .  FIG. 17  shows an alternative connection means in the form of Velcro (registered trademark) fasteners. Instead of Velcro strip material, it is also conceivable that the fasteners may consist of magnetic tabs, or any other suitable fastening means. 
         [0058]    Referring now to  FIGS. 18A , there is shown a further modification of the duvet cover and namely the possibility of modifying the thermal insulating factor of the duvet cover. This can be accomplished by inserting into the pouch a further down insulation sheet  73 ′, as shown in  FIG. 18A , which has a different insulation factor, for example  60  grams/sq. meter over a slightly thicker insulation sheet  73  of  120  grams/sq. meter. The second sheet  73 ′ is also provided with attachment tabs  77  which are secured to the pouch tabs  74  of the tabs of the other down insulation sheet  73 . 
         [0059]      FIG. 188  illustrates a further embodiment in that a smaller or sectional down insulation sheet  73 ″ is secured inside the pouch and extends in a specific portion of the pouch to suit the need of a person sleeping on one side of a bed with the duvet cover on its side having a higher thermal insulating factor that the other side. Also, a sectional down insulation sheet may be attached across a lower portion of the pouch  70  to provide more warmth in the feet area of the duvet cover. 
         [0060]    It is within the ambit of the present invention to cover various obvious modifications of the embodiments and examples described herein provided such modifications fall within the scope of the appended claims.