Patent Publication Number: US-2016242559-A1

Title: Cover sheet for covering a mattress and a cover sheet positioning system

Description:
The present invention relates to a cover sheet for covering a mattress, for example particularly, but not exclusively, a sheet with positioning system. 
     BACKGROUND OF THE INVENTION 
     Both flat sheet and fitted sheets are cloth generally used to cover a mattress. A flat sheet is usually a rectangular cloth while a fitted sheet has its four corners and sometimes two or four sides fitted with elastic. Flat sheets are more often used by hotels while fitted sheets are used domestically. 
     To fit a flat sheet onto a mattress, the lower edges of the flat sheet are folded underneath the mattress. The weight of the mattress retains the lower edges of the flat sheet underneath it. In order for this to work effectively, an additional 43% of the flat sheet is tucked underneath the mattress. The 43% of fabric is not useful in covering the mattress. The material used in treating e.g. cleaning and ironing the 43% of fabric would constitute substantial wastage. Cutting down the amount of fabric to be placed underneath the mattress is not desirable as there may not be enough friction to retain the flat sheet. The use of fitted sheet solves part of the problem but to fit a fitted sheet, the mattress has to be lifted for tucking in the parts fitted with elastics. Lifting a mattress is extremely labor intensive. 
     The invention seeks to eliminate or at least to mitigate such shortcomings by providing an improved sheet for mattress. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is provided a cover sheet for covering a mattress comprising a body having a pair of opposite side edge portions; and an elongate receptacle formed along each of the opposite side edge portions for holding a respective elongate positioning member; wherein each of the elongate receptacles is provided with an opening dimensioned for inserting of the elongate positioning member there through and into the receptacle to be held therein. 
     Preferably, the body has a second pair of opposite side edge portions formed with respective elongate receptacles. 
     More preferably, one of the opposite side edge portions of the second pair is narrower than the other side portion of the same second pair. 
     Advantageously, the two side edge portions of each adjacent pair are inter-connected by a web. 
     More advantageously, each elongate receptacle extends along an extreme edge of the respective side edge portion. 
     Preferably, each elongate receptacle is integrally formed with the respective side edge portion. 
     More preferably, each elongate receptacle extends along substantially the entire length of the respective side edge portion. 
     It is preferable that a plurality of elongate positioning members, each being adapted to be inserted into a respective said elongate receptacle for stiffening the respective side edge portion of the body. 
     Preferably, each elongate positioning member is substantially as long as the respective elongate receptacle. 
     In another aspect of the invention there is provided a cover sheet positioning system comprising at least two elongate positioning members arranged for use on opposite side edge portions of a cover sheet, being operatively subject to a downward force so as to maintain a said cover sheet flat on a mattress protected by the cover sheet. 
     Preferably, including at least two holders each co-operable with a respective said elongate positioning member, each holder having a first part adapted to attach the respective elongate positioning member and a second part adapted to engage with (by frictional engagement) the bottom side of said mattress. 
     More preferably, the first part extends orthogonal to the second part. 
     Yet more preferably, the second part defines a space for accommodating the elongate positioning member and includes a retainer for retaining the elongate positioning member inside the space. 
     It is preferable that the retainer comprises a pair of protrusions together forming a restricted opening to the space for retaining the elongate positioning member inside the space. 
     More preferably, the protrusions are provided on respective resiliently flexible arms of the second part. 
     Advantageously, the elongate positioning member has a cross-section having different dimensions measured along respective first and second directions such that the elongate positioning member is laterally insertable through the restricted opening in the first direction but not the second direction. 
     More advantageously, the first direction extends orthogonal to the second direction. 
     Yet more advantageously, the cross-section is T-shaped. 
     Preferably, the second portion has an upper surface for engaging the mattress, the upper surface being provided with a plurality of bumps for enhancing engagement with the mattress. 
     It is preferable that the second portion is corrugated for enhancing engagement with the mattress. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic perspective view of a mattress covered by a sheet in accordance with the invention; 
         FIG. 1B  is an enlarged schematic diagram of a retainer used in the mattress in  FIG. 1 ; 
         FIG. 2  is a schematic left side view of the mattress and the sheet in  FIG. 1 ; 
         FIG. 2A  is an enlarged schematic side view of a front end of the sheet in  FIG. 2 ; 
         FIG. 2B  is an enlarged schematic view of a retainer provided on a side of the mattress in  FIG. 2 ; 
         FIG. 2C  is an enlarged schematic cross-sectional view of the retainer in  FIG. 2B  and its interaction with a positioning member in  FIG. 2 ; 
         FIG. 3  is a schematic right side view of the mattress and the sheet in  FIG. 1 ; 
         FIG. 3A  is an enlarged cross-sectional view of the positioning member in  FIG. 3 ; 
         FIG. 3B  is an enlarged schematic view of a retainer provided on a side of the mattress in  FIG. 3 ; 
         FIG. 3C  is an enlarged side view of a front end in  FIG. 3 ; 
         FIG. 4  is a schematic rear view of the mattress and the sheet in  FIG. 1 ; 
         FIG. 4A  is an enlarged schematic view of a retainer on a rear end of the mattress in  FIG. 4 ; 
         FIG. 5  is a schematic front view of the mattress and the sheet in  FIG. 1 ; 
         FIG. 6  is a schematic top plan view of an embodiment of a sheet in accordance with the invention and as fitted on the mattress in  FIG. 1 ; 
         FIG. 7  is a schematic top plan view of the sheet in  FIG. 6 ; 
         FIG. 8  is a schematic top plan view of the mattress covered by the sheet in  FIG. 1 ; 
         FIG. 9  is a schematic perspective view of a further embodiment of a mattress covered by a sheet in accordance with the invention; 
         FIG. 10  is a schematic perspective view of the retainer in  FIG. 1B  with an elongate positioning member retained therein; 
         FIG. 11  is a schematic perspective view of the retainer in  FIG. 10  without the elongate positioning member; 
         FIG. 12  is a schematic side view of the retainer in  FIG. 10  with the elongate positioning member in  FIG. 10  inserting into the holder and at a non-operating position; 
         FIG. 13  is a schematic side view of the retainer in  FIG. 12  with the elongate positioning member in an operating position and retained by the holder; 
         FIG. 14  is a schematic perspective view of a further embodiment of a holder in accordance with the invention retaining an elongate positioning member; 
         FIG. 15  is a perspective view of the holder in  FIG. 14  without the elongate positioning member; and 
         FIG. 16  is a bottom plan view of the mattress in  FIG. 1  showing the arrangement of nine holders in the mattress. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring initially to  FIGS. 1 to 8  of the drawings, there is shown a bed with a mattress covered or protected by a cover sheet  100  embodying the invention. The cover sheet  100  is in the form of a flat sheet with four rounded corners. The cover sheet  100  has a body with two pairs of opposite side edge portions  100 A,  100 B,  100 C, and  100 D around the body, i.e., a first pair of opposite right and left side edge portions  100 A and  100 C and a second pair of opposite head and tail side edge portions  100 B and  100 D. The rounded corners form respective webs between adjacent side portions  100 A and  100 B,  100 B and  100 C,  100 C and  100 D,  100 D and  100 A, such that the body has an unbroken or intact periphery. When the cover sheet  100  is in use, i.e. placed on a mattress to cover the same, its side edge portions  100 A,  100 B,  100 C and  100 D hang downward and cover at least partly over the four sides respectively of the mattress. Ideally, the width of the side edge portions  100 A,  100 B,  100 C and  100 D has to be sufficient to cover and conceal the entire thickness (or at least part thereof) of the mattress. The head side edge portion  100 B may be shorter, i.e. narrower, than the other side edge portions  100 A,  100 C, and  100 D, as the mattress&#39;s head side is often concealed by a headboard. 
     In the preferred embodiment, four elongate receptacles  101 A,  101 B,  101 C, and  101 D are provided on the side edge portions  100 A,  100 B,  100 C, and  100 D of the cover sheet  100  respectively. In another embodiment, only one pair of the opposite side edge portions  100 A and  100 C may be provided with elongate receptacles  101 A and  101 C. 
     The elongate receptacles  101 A,  101 B,  101 C and  101 D are pockets or sleeves formed from the fabric of the r corresponding side edge portions  100 A,  100 B,  100 C and  100 D. Alternatively, they may be pre-formed, e.g. as tubes, and sewed onto the respective side edge portions  100 A,  100 B,  100 C and  100 D. Each elongate receptacle  101 A/ 101 B/ 101 C/ 101 D may be located at any position (i.e. vertical position in use) within the width of the respective side edge portion  100 A/ 100 B/ 100 C/ 100 D. Generally, it should preferably, but not necessarily, run parallel to the extreme or free edge of the side edge portion  100 A/ 100 B/ 100 C, 100 D. In a preferred embodiment, each elongate receptacle  101 A/ 101 B/ 101 C/ 101 D is provided right at the extreme edge of the respective side edge portion  100 A/ 100 B/ 100 C/ 100 D. 
     Each elongate receptacle  101 A/ 101 B/ 101 C/ 101 D has at least one or preferably two openings  102 A/ 102 B at opposite ends thereof, for insertion of an elongate positioning member  103 A,  103 B,  103 C or  103 D. In other words, the elongate receptacles  101 A to  101 D form respective open-ended channels. The dimensions, e.g. length and width, of the elongate receptacles  101 A to  101 D are comparable to, or marginally larger than, those of the elongate positioning members  103 A to  103 D, such that the elongate positioning members  103 A to  103 D are accommodated or held fittingly within the respective elongate receptacles  101 A to  101 D. Each elongate receptacle  101 A/ 101 B/ 101 C/ 101 D, together with the corresponding elongate positioning members  103 A/ 103 B/ 103 C/ 103 D therein, preferably extend along substantially or almost the full length of the respective side edge portion  100 A/ 100 B/ 100 C/ 100 D, so as to stiffen the entire side edge portion  100 A/ 100 B/ 100 C/ 100 D. 
     Each elongate positioning member  103 A/ 103 B/ 103 C/ 103 D is a cylindrical rod or stick, preferably with a solid cross-section to maximize its weight. In an alternative embodiment, the elongate positioning member  103 A/ 103 B/ 103 C/ 103 D may be hollow to lower the costs in production. Cross-section, taken traverse to length of the through-hole in the elongate positioning member  103 A/ 103 B/ 103 C/ 103 D, may be of any shape. 
     When in use, the elongate positioning member  103 A/ 103 B/ 103 C/ 103 D is adapted or sized to be inserted into the respective elongate receptacle  101 A/ 101 B/ 101 C/ 101 D for adding stiffness as well as weight to the entire length of the respective side edge portion  103 A/ 103 B/ 103 C/ 103 D of the cover sheet  100 . 
     The weight of at least two elongate positioning members  103 A and  103 C co-operatively prevents the cover sheet  100  from sliding or shifting over the mattress. They are in use subject to a downward (i.e. gravitational) force so as to maintain the cover sheet  100  flat on the mattress. In the preferred embodiment, all four elongate receptacles  101 A to  101 D hold respective elongate positioning members  103 A to  103 D. The weight of these elongate positioning members  103 A to  103 D stretches and flattens the cover sheet  100  while operatively prevents the cover sheet  100  from shifting over the mattress. In the preferred embodiment, each of the elongate positioning members  103 A to  103 D is substantially as long as the respective elongate receptacle  101 A/ 101 B/ 101 C/ 101 D. 
     The elongate positioning members  103 A to  103 D may have an oval or T-shaped cross-section, other than a circular cross-section, taken transversely of its longitudinal axis i.e. length. Referring to  FIGS. 12 and 13 , the elongate positioning members  103 A to  103 D are of a generally T-shaped cross-section that has different dimensions A and B measured along respective first and second directions, with one dimension being smaller than the other. The first and second directions extend at right angles or orthogonal to each other. 
     To enhance the function and/or performance of the elongate positioning members  103 A to  103 C on the three exposed sides of the mattress, a plurality of holders  104  are employed to positively hold them in position. In the preferred embodiment as shown in  FIG. 16 , each of the elongate positioning members  103 A to  103 C is caught or held by a series of three holders  104 . There are in total nine such holders  104 , which are evenly spread along the three sides of the mattress. 
     In passing, it is noted that the remaining elongate positioning member  103 B on the head side of the mattress may be left out, as this elongate positioning member  103 B with the associated head side edge portion  100 B is often tucked in and compressed between the mattress and the headboard. This arrangement results in extra gripping holding force, which adds to the gravitational force upon the elongate positioning member  103 B, and the resultant force would provide the necessary holding force for the elongate positioning member  103 B to keep the head side edge portion  100 B of the cover sheet  100  in position. 
       FIGS. 11 and 15  show two different embodiments of the holders  104 . The embodiment of  FIG. 11  is mainly for use in a hotel or the like accommodation facilities where the mattresses are often stacked onto a matching flat-topped base support such that the mattress bottom is readily accessible. The embodiment of  FIG. 15  is designed primarily for use at home where the mattresses are usually located in a shallow recessed base platform that conceals the bottom of the mattress. 
     The two embodiments share a common one-piece or integral basic structure having a generally horizontal first/inner part  104 A and a generally vertical second/outer  104 B, which therefore extend orthogonal to each other. The inner part  104 A has a corrugated (or wavy) body  104 A- 1  and a flat neck  104 A- 2 . The corrugated body  104 A- 1  has a number of bumps  105  scattered evenly over its upper surface. The corrugation and the bumps  105  are features to enhance frictional or gripping engagement between the holder  104  and the mattress. In use, the inner part  104 A is tucked in and compressed between the bottom of the mattress and the upper surface of the mattress&#39;s base support, such that it is retained or stays therein primarily by friction. With the aforesaid enhancement features, the inner part  104 A can be more reliably fixed in position for use. 
     The outer part  104 B is exposed and located alongside the mattress. It acts as a retainer  104 B- 1 , and has an inner space to accommodate an associated elongate positioning member and is preferably an open-ended retainer for retaining the elongate positioning member inside the space. The retainer  104 B- 1  preferably has a U-shaped structure with a pair of opposed protrusions  104 B- 1  which together form a restricted opening or bottleneck to the space for retaining the elongate position member therein. The protrusions  104 B- 1  are supported on respective resiliently flexible arms  104 B- 2  which are provided by two limbs of the U-shaped structure and may be flexed outwardly to widen the opening or bottleneck slightly. 
     Referring to the holder  104  of  FIG. 11 , the retainer  104 B- 1  is located close to and slightly downwards from the horizontal inner part  104 A. As to the other holder  104  of  FIGS. 14 and 15 , its retainer  104 B- 1  is raised above the horizontal inner part  104 A by an upturned section  104 A- 3  of the neck  104 A- 2 . The upturned section  104 A- 3  serves to locate and expose the retainer  104 B- 1  out of an aforesaid shallow recessed base platform, while allowing the inner part  104 A to be tucked in the recess of the base platform and underneath the mattress. 
     Referring now to  FIGS. 10 to 15 , for an elongate positioning member  103 A/ 103 B/ 103 C/ 103 D with a circular cross-section, it is to be squeezed past the bottleneck or restricted opening of an associated holder  104 , with the protrusions  104 B- 1  being slightly deformed or the arms  104 B- 2  slightly flexed outwards. In the case of an elongate positioning member  103 A/ 103 B/ 103 C/ 103 D having a generally T-shaped or oval cross-section, it should still be squeezed past the restricted opening, but the extent to which the arms  104 B- 2  need to flex is comparatively lesser. More specifically, for insertion through the restricted opening, the elongate positioning member  103 A/ 103 B/ 103 C/ 103 D is initially placed in a first orientation with the first dimension A stretching across the restricted opening i.e. between the protrusions  104 B- 1 . Once it has passed restricted opening, the elongate positioning member  103 A/ 103 B/ 103 C/ 103 D is then rotated through 90° to a second orientation with the second dimension B stretching across the space between the arms  104 B- 2 . The second dimension B is relatively larger than the first dimension A. The elongate positioning member  103 A/ 103 B/ 103 C/ 103 D will be locked inside the space by the protrusions  104 B- 1  (upon the arms  104 B- 2  flexing back inwardly), or at least blocked from passing back out through the restricted opening (see  FIGS. 12 and 13 ) during normal use of the cover sheet  100  held in position by the holders  104 . 
     In an alternative embodiment of the cover sheet positioning device as shown in  FIG. 9 , the holders  104  are omitted. Only two elongate positioning members  103 A and  103 C are in use, which are inserted into respective elongate receptacles  101 A and  101 C. Under the action of gravity, the two elongate positioning members  101 A and  101 C act upon opposite right and left side edge portions  100 A and  100 C of a cover sheet  100  by being subject to a downward force by their own weight so as to maintain the cover sheet  100  flat on the mattress. In a more preferred embodiment, four elongate positioning members  103 A to  103  D are used, inserted into respective elongate receptacles  101 A to  101 D on all four sides, so as to stop the cover sheet  100  shifting up and down in addition to left and right. 
     To cater for variations in the mattress size/thickness, the cover sheets of the present invention are supplied in a range of sizes and dimensions. Alternatively, the cover sheets may be available in only one size or limited sizes but with choice of different positions for the elongate receptacles  101 A to  101 D relative to or across width of the side edge portions  100 A to  100 D. 
     The invention has been given by way of example only, and various other modifications of and/or alterations to the described embodiments may be made by persons skilled in the art without departing from the scope of the invention as specified in the appended claims.