Patent Document

This application is a continuation-in-part of patent application Ser. No. 09/976,797 filed on Oct. 12, 2001, now U.S. Pat No. 6,651,278, the contents of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to bed sheets that are adapted to facilitate ease of changing and replacing the sheets on a mattress and, more particularly, to a bed sheet set having an upper sheet portion and a lower sheet portion which, in conjunction, enclose the mattress and, further, wherein a waterproof panel is positionable between the upper sheet and the top of the mattress. 
   2. Discussion of the Related Art 
   There are numerous combinations of bed sheets which are designed to provide a quick and easy way to change bed linen. Most notably, it is known to provide a fitted sheet which is tailored to provide a tight, neat and wrinkle-free fit when secured to the mattress. The well known fitted sheet design provides elastic material around the corner edges to allow the corner edges to contract on the underside of the mattress in a manner which secures the fitted sheet in place so that the top surface of the sheet is pulled tight and flat on the top sleeping side of the mattress. When it is necessary to wash and change the sheets, the fitted sheet is fairly easy to remove from the mattress by pulling up on the corners. Replacing the fitted sheet on the mattress, however, is known to be problematic, especially if the sheet shrinks after washing and drying. It is often difficult to stretch the fitted sheet over the corners of the mattress in a manner which properly secures the elastic corner edges of the fitted sheet under the mattress. And, even if the fitted sheet is properly secured to the mattress, the corners are sometimes dislodged by the forces of body movement when sleeping. 
   The problems associated with fitted mattress sheets, having elastic corners, as described above, are of particular concern in the field of baby linen for crib mattresses. Specifically, the need to tuck the elastic edge corners of the fitted sheet around the underside of the mattress requires lifting of a crib mattress out from the crib each time the linens are changed. More importantly, fitted sheets can be easily dislodged from the mattress while an infant is in a crib. Oftentimes the person changing the crib sheets fails to properly secure the elastic corners of the sheet under the mattress, particularly if the fitted sheet shrinks from washing and does not fit easily over the mattress corners. And, even when properly secured to the mattress, fitted crib sheets can be pulled loose by an infant. This is particularly worrisome due to studies which have shown that many cases of Sudden Infant Death Syndrome (SIDS) are a result of smothering due to loose linen, blankets and/or pillows in a crib. For example, if the mattress sheet comes loose, there is danger of an infant becoming entangled or wrapped in the sheet when tossing and turning in the crib, which could possibly lead to suffocation. 
   The need to frequently change and wash bed linens is especially a concern with infants, small children and elderly bedridden individuals. Accordingly, in addition to the need for a quick and easy way to change bed linen, there is also a need, in many instances, for a linen accessory which provides waterproof properties in order to protect the mattress. With the aging of the population, there is an increasing number of people, both in institutions and at home, who spend much of their time bedridden. For many of these individuals, the bed is used for sleeping at night time and is also used for daily activities (e.g. phone calls, reading, watching television, etc.) while the person is awake. When sleeping, it may be desirable to use a protective sheet having waterproof properties to guard against damaging the mattress at night. However, most waterproof sheets do not provide good airflow through the fabric and become hot and uncomfortable over a period of time. In the instance an individual is confined to the bed during the day, it may be desirable to remove the waterproof sheet in order to provide better ventilation and increased comfort. 
   In the past, others have proposed various bed linen arrangements for application to a mattress. For instance, Blake U.S. Pat. Nos. 5,086,530 and 4,922,565 disclose a set of bed linen having a top panel that is moisture proof and a bottom fitted sheet that extends partially under a mattress to secure the bottom fitted sheet in the same manner as a conventional fitted sheet. The top panel and bottom sheet have cooperating fasteners that allow the top panel to be removed and replaced from the mattress without disturbing the fitted sheet. The top panel and bottom sheet do not enclose the mattress. 
   U.S. Pat. No. 6,067,677 to Reen et al. teaches a bed sheet in the form of a pouch with an open mouth. The pouch encloses a mattress. The sheet has a flap which is folded to close the open mouth. The sheet and the flap have cooperating fasteners to hold the flap in place. 
   U.S. Pat. No. 5,701,617 to Colby teaches a bottom bed sheet folded about a mattress. The bed sheet has two end portions of water permeable textile attached on opposite sides of a moisture resistant center portion. The moisture resistant portion has a textile portion superimposed and fastened to the water resistant portion. The fasteners are releasable. 
   Accordingly, there remains an urgent need in the art of bed linen for an improved bed sheet arrangement which provides for quick and easy changing of bed linen, while also providing a tight, neat, wrinkle-free and secure fit of the sheets to the mattress. There is a further need in the art for a bed sheet set which remains fitted and secured to the mattress during use and which provides for selective use of a waterproof panel to protect the underlying mattress from contact with moisture and liquids, including bodily fluids. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a set of sheets including an upper sheet with a top panel and a lower sheet with a bottom panel. In conjunction, the upper and lower sheets are sized, structured and configured to enclose a mattress. A waterproof panel is positioned between the upper sheet and the top of the mattress to protect the mattress from damaging exposure to moisture and liquids, including bodily fluids. In several embodiments, the upper sheet and waterproof panel are removable for washing and changing thereof while the lower sheet remains fitted to the mattress, thereby avoiding the need to lift or move the mattress when changing the sheets. The waterproof panel may be independently removable to selectively control air permeability of the sheets, and particularly the upper sheet. In a further embodiment, a minor waterproof panel is removably attachable in covering relation to a portion of the top surface of the upper sheet to protect the upper sheet and mattress from becoming soiled, and thereby extending the period of time between laundering and changing of the set of sheets. 
   OBJECTS AND ADVANTAGES OF THE INVENTION 
   With the foregoing in mind, it is a primary object of the present invention to provide a set of bed sheets structured and disposed to permit quick and easy changing of the bed linen without moving or disturbing the mattress. 
   It is a further object of the present invention to provide a set of bed sheets which may be used in a protective waterproof mode to protect the mattress and a comfort mode wherein air is permitted to permeate between the mattress and top sheet covering the mattress. 
   It is still a further object of the present invention to provide a set of bed sheets including a lower sheet which covers the bottom and sides of a mattress, an upper air-permeable sheet which releasably fastens to the lower sheet so that the upper and lower sheets enclose the mattress, and a less air-permeable waterproof panel which is selectively positionable between the upper sheet and the mattress. 
   It is still a further object of the present invention to provide a set of bed sheets which provides for the discretionary removal of the upper sheet, with or without removal of the waterproof panel, without removing the lower sheet from the mattress. 
   It is still a further object of the present invention to provide a set of bed sheets which is particularly suited for use on a crib mattress and wherein the set of bed sheets includes an upper sheet and a lower sheet which, in conjunction, enclose the crib mattress and remain secured thereto during use, without being dislodged, and further wherein the set of bed sheets includes a waterproof panel for selective positioning between the upper sheet and the top of the crib mattress. 
   These and other objects and advantages of the present invention are more readily apparent with reference to the following detailed description taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is an exploded perspective view showing the separable components of the quick-change bed sheet set of the present invention in relation to a mattress, in accordance with one preferred embodiment thereof; 
       FIG. 2  is a top perspective view showing the quick-change bed sheet set of the embodiment of  FIG. 1  secured to a mattress; 
       FIG. 3   a  is a cross-sectional view taken along the plane indicated by the line  3 — 3  in  FIG. 2 ; 
       FIG. 3   b  is a cross-sectional view illustrating an alternative embodiment of the quick-change bed sheet set taken along the plane indicated by the line  3 — 3  in  FIG. 2 ; 
       FIG. 4  is a top perspective view of the quick-change bed sheet set of the present invention in accordance with yet a further embodiment thereof, wherein a minor panel is secured about the mattress in covering relation to a portion of the upper sheet and sides of the lower sheet of the bed sheet set; 
       FIG. 5  is a cross-sectional view taken along the plane of the line indicated as  5 — 5  in  FIG. 4 ; 
       FIG. 6  is a top perspective view illustrating yet a further embodiment of the quick-change bed sheet set of the present invention secured to a mattress; 
       FIG. 7  is a top perspective view illustrating removal of the bed sheet set of  FIG. 6  from the mattress; and 
       FIG. 8  is a top perspective view illustrating yet a further embodiment of the quick-change bed sheet set of the present invention shown secured to a mattress. 
   

   Like reference numerals refer to like parts throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the several views of the drawings, several embodiments of the bed sheet set of the present invention are shown, wherein the bed sheet set is generally indicated as  10 . In each of the embodiments, the bed sheet set  10  includes a lower sheet  20  and an upper sheet  30  which, in conjunction, are structured to enclose a mattress  100  having a top sleeping surface  102 , a bottom side  104  and vertical sides  106 . 
   A first preferred embodiment of the bed sheet set  10  is shown in  FIGS. 1-3   a,  wherein the mattress  100  is partly encompassed by the lower sheet  20 . The lower sheet  20  is preferably structured to include a rectangular main bottom panel  21  and upstanding sidewalls  24  about the periphery. The bottom panel  21  has an inner surface  22  and an outer surface  23 . The juncture between the bottom panel  21  and side walls  24  may be of conventional construction with seamed edges to facilitate a snug, uniform fit about the bottom  102  and sides  106  of the mattress  100 . The lower sheet  20  may be of a woven or knitted cotton or other conventional threads or yarns with a thread count determining the softness and air permeability of the panel. 
   A fastener  25  extends about the peripheral zone  26  on the sidewalls  24  of the lower sheet  20 . The location of the fastener  25  is such that when the lower sheet  20  is fitted onto the mattress  100 , the fastener  25  is disposed about the sides  106  of the mattress. The fastener  25  may be of a series of cooperating fasteners, such as opposite sides of a zipper, cooperating button and buttonholes, male and female snaps, or hook and loop fabric such as VELCRO or releasable cohesive materials. The fasteners should be of materials that will withstand numerous use and laundering cycles. In one preferred embodiment, the cooperating fasteners are defined by non-corrosive zippers which join the lower sheet  20  and upper sheet  30  about their entire correspondingly positioned peripheral edge zones to completely enclose the mattress  100  therein. 
   The upper sheet  30  is defined by an air-permeable main top panel  31  having a top outer surface  32 , an inner surface  34 , and a peripheral extremity  35  to completely overly the top sleeping surface  102  of the mattress  100 . In a preferred embodiment, the peripheral extremity  35  of the upper sheet  30  extends partially down the sidewalls  106  of the mattress, just below the top peripheral edge  108  with the inner surface  34  facing the top sleeping surface  102  of the mattress  100 . Alternatively, the upper sheet  30  may be sized to cover the top surface  102  of the mattress only, with the peripheral extremity of the upper sheet aligned with the top edge  108  or positioned just inside the top edge  108  of the mattress  100 . There is a first fastener  37  attached to the peripheral edge zone  36  of the upper sheet  30 . This fastener is the cooperating opposite part of the fastener  25  described above. A fly or flap  38  extends from the peripheral edge zone  36  to cover the cooperating fasteners  25 ,  37  of the lower and upper panels when the fasteners are attached. The upper sheet  30  may be of the same or similar material as the lower sheet  20  with similar thread count and air permeability. The threads or yarns may be natural or synthetic and, possibly, hydrophobic to increase the resistance of the panel to penetration of fluids. 
   The lower and upper sheets may be deployed, alone, during waking hours, when a person using the bed may be capable of managing the bodily functions. During this period, the air permeability of the bed sheet set  10  is normal without excessive heat buildup. The exposure of the upper sheet  30  will dictate changing on a regular basis, for example every three days or once a week. At such time, the cooperating fasteners  25 ,  37  will be unfastened, thereby allowing the upper sheet  30  to be removed and laundered while the lower sheet  20  remains in place and undisturbed. 
   As seen in  FIGS. 1-3   b,  the bed sheet set  10  further includes a moisture proof major panel  40  adapted for positioning between the top sleeping surface  102  of the mattress  100  and the inner surface  34  of the top panel  31 . The moisture proof major panel  40  is sized, structured and configured to cover at least a portion of the area of the top sleeping surface  102  and, in a preferred embodiment, the moisture proof major panel  40  covers the entire mattress top sleeping surface  102 . The major panel  40  is structured to include an absorbent top side  42  and a waterproof underside  44 . The absorbent top side  42  faces the inner surface  34  of the top panel  31  while the waterproof side  44  faces the top surface  102  of the mattress. 
   In one embodiment, the moisture proof major panel  40  is selectively positionable between the upper sheet and the mattress  100  and may be removed when desired to allow greater ventilation and to avoid excessive heat buildup. During sleeping hours, or when it is otherwise desired to protect the mattress, the major panel  40  can be inserted between the upper sheet  30  and mattress  100 . As best seen in  FIG. 1 , cooperating releasable fasteners  46  and  48  are provided on the absorbent side  42  of the major panel  40  and the inner surface of the top panel  31 , respectively, to facilitate attachment of the major panel  40  to the upper sheet  30  in a manner which prevents unwanted traveling or bunching up of the major panel  40  below the upper sheet  30  due to movement of the person lying on the bed or crib mattress. 
   In another embodiment, as seen in  FIG. 3   b,  the moisture proof major panel  40  is permanently sewn to the top panel  31 , on the underside  34 . In this instance, the major panel  40  may be stitched or otherwise attached to the inner surface  34  of the top panel  31  or, alternatively, sandwiched between two sheet layers making up the top panel  31  and stitched or otherwise secured in place. 
   In either embodiment, as described above, when it is necessary to change the upper sheet  30 , both the upper sheet  30  and major panel  40  are removed from the mattress and lower sheet  20  by unfastening the cooperating fasteners  25 ,  37 . The major panel  40  may then be laundered along with the upper sheet  30  or, in the embodiment of  FIGS. 1-3   a,  if the major panel  40  has not been soiled it can be simply replaced on the top  102  of the mattress  100  for subsequent attachment to the inner surface  34  of the top panel  31  once the upper sheet  30  has been washed and dried. 
   In a further embodiment, as shown in  FIGS. 4 and 5 , the lower sheet  20  is provided with releasable fasteners  50  on the bottom outer surface  23 . A minor panel  60 , as shown in  FIGS. 4 and 5 , for covering a portion of the upper sheet  30  is shown with corresponding fastener elements  62  for releasably connecting to the fastener elements  50  on the bottom of the lower sheet  20 . The minor panel  60  is waterproof with an absorbent layer sandwiched between opposing fabric panels which may be formed of cotton, synthetic or other conventional bed linen materials. Alternatively, the minor panel  60  may be made of a combination of an absorbent fabric on the top with a liquid impervious film backing on the bottom side. The minor panel  60  is intended to protect a remainder of the bed sheet set  10 , including the upper sheet  30 , major panel  40  (if used) and lower sheet  20 , as well as the mattress  100 , from liquid discharges, such as drooling, nasal discharges or beverage spills (e.g. leaking nursing bottles). The minor panel  60  may be of varying sizes to cover different portions of the top panel  31  of the upper sheet  30  in accordance with the particular needs of the user. The minor panel  60  helps to reduce the number of required bed linen changes and laundering, by protecting the remainder of the bed sheet set  10 . When the minor panel  60  becomes soiled, it can be simply removed, by unfastening the cooperating fasteners  50 ,  62  on the underside of the lower sheet  20 , below the mattress, and removing the minor panel  60  from the bed sheet set  10  and mattress  100 . The minor panel  60  can then be conveniently laundered and replaced as needed. Further, the use of the minor panel  60  will allow the caregiver or the user to remove only the soiled minor panel portion of the bed sheet set  10  and replace it with another clean minor panel quickly and easily without disrupting the remainder of the bed sheet set  10  and mattress. 
   Referring to  FIGS. 6 and 7 , yet a further embodiment of the bed sheet set  10  is shown wherein the lower sheet  20 ′ and upper sheet  30 ′ are permanently joined together in the form of a casing  70   a  which is sized, structured and configured to enclose the mattress  100 . A flap portion  72  of the casing  70   a  unfolds to reveal an opening  74  which allows the end of the mattress to be slid within the interior of the bed sheet casing  70   a.  The casing  70   a  can then be pulled over and around the sides of the mattress  100  so that the mattress is completely tucked within the casing  70   a  defined by the combined lower and upper sheets  20 ′,  30 ′, respectively. The flap  72  can then be closed and secured with cooperating fasteners  76 ,  78 , such as hook and loop fasteners, to completely encapsulate the mattress within the bed sheet enclosure. In this particular embodiment, the moisture proof major panel  40  may be used, as desired, and may be provided as an independent component, as shown and described in connection with  FIGS. 1-3   a,  or, alternatively, the major panel  40  may be permanently stitched or otherwise attached to the inner side of the upper sheet  30 ′. 
     FIG. 8  shows a further embodiment of the bed sheet enclosure  70   b  defined by the combined lower sheet  20 ′ and upper sheet  30 ′ which are permanently secured together as an integral one-piece component, similar to the embodiment of  FIGS. 6-7 . In the embodiment of  FIG. 8 , the flap  72  is located at the end of the bed sheet enclosure, partially extending down the end sidewall  24 ′, thereby providing a convenient opening  74  when the flap  72  is unfolded. This allows the bed sheet enclosure  70   b  to be slipped over the end of the mattress  100  and pulled along the length of the mattress so that the mattress is tucked and secured in enclosed relation within the bed sheet enclosure. The flap  72  can then be secured closed, using the cooperating releasable fasteners  76 ,  78 , in the same general manner as described in connection with the embodiment of  FIGS. 6-7 . Again, the major panel  40  may be provided as a separate component and inserted between the upper sheet  30 ′ and mattress  100 , or, alternatively, the major panel  40  may be permanently stitched or otherwise secured under the inner side of the upper sheet  30 ′ in the manner as described in the previous embodiments of  FIGS. 1-3   b.    
   The instant invention provides a method of safely securing a bed sheet set to a mattress while allowing for quick changing of the bed sheets for laundering as necessary comprising the steps of: 
   (a) providing the set of bed sheets with an absorbent porous lower sheet having an attached continuous fastener; 
   (b) securing the lower sheet about a mattress such that the fastener is disposed about the perimeter of the mattress; 
   (c) providing the bed sheet set with an absorbent porous upper sheet having a first attached continuous fastener; 
   (d) providing a moisture proof panel sized, structured and configured to cover at least a portion of the area of the top of the mattress; 
   (e) releasably securing the continuous fastener on the lower sheet to the continuous fastener on the upper sheet to enclose the mattress therein; 
   (f) selectively placing the moisture proof major panel between the upper sheet and the top of the mattress; and 
   (g) removing the upper sheet and the major panel from the mattress and the lower sheet by unfastening the cooperating continuous fasteners on the upper sheet and the lower sheet, thereby allowing the upper sheet and/or the major panel to be laundered and replaced while the lower sheet and mattress remain stationery, in place and undisturbed. 
   Further, the instant invention provides a method of changing the air permeability of a set of bed sheets during use comprising the steps recited above, wherein the air permeability of the bed sheet set can be changed by selectively removing or inserting the moisture proof major panel between the upper sheet  30  and the mattress  100 . 
   The invention further provides a method of extending the period of time between changes of a set of bed sheets comprising the steps of: 
   (a) providing the set with an absorbent porous lower sheet having an attached continuous fastener and a third attached fastener; 
   (b) securing the lower sheet about a mattress such that the fastener is disposed about the perimeter of the mattress; 
   (c) providing the set with an absorbent porous upper sheet having a first attached continuous fastener and a second attached fastener; 
   (d) releasably securing the continuous fastener on the lower sheet to the first continuous fastener on the upper sheet to enclose the mattress in encapsulated relation between the lower sheet and upper sheet; 
   (e) providing the bed sheet set with a waterproof major panel and a plurality of waterproof minor panels each having discreet edges and a fastener attached about their edges; 
   (f) selectively placing the major panel between the upper sheet and the top of the mattress and releasably securing a fastener on the waterproof major panel with the second fastener on the upper sheet; 
   (g) providing the bed sheet set with a plurality of minor waterproof panels each having a releasable fastener; 
   (h) releasably securing a fastener on one of the minor panels to the third attached fastener of the lower sheet with the minor panel extending over and covering a portion of the upper sheet; 
   (i) detaching one of the plurality of minor panels from the lower sheet while retaining the upper and lower sheets on the mattress; and 
   (j) releasably securing the fastener of another of the plurality of minor panels to the third fastener of the lower sheet so that the minor panel extends over and covers the upper sheet, thereby extending the time between changes of the upper and lower sheet components of the bed sheet set. 
   While the instant invention has been shown and described in accordance with various preferred and practical embodiments thereof, it is recognized that departures from the instant disclosure are contemplated within the spirit and scope of the present invention which, therefore, should not be limited except as defined in the following claims as interpreted under the doctrine of equivalents.

Technology Category: 4