Cushion with cover

Abstract

Provided is a cushion with a cover that achieves both improved cover detachability and suppressed cover displacement. This cushion with a cover comprises a rectangular parallelepiped cushion body and a cover for covering the cushion body. The cover includes a fabric that covers the side surfaces and a top surface of the cushion body, and a fixing member attached to the fabric. The cover has an opening on the lower side allowing for the accommodation of the cushion body. The fixing member includes: a corner-corresponding portion that corresponds to each of the four corners of a bottom surface of the cushion body and is hooked in the vicinity of the corresponding corner of the bottom surface to suppress positional misalignment; and a connection portion that is a member with a stretch rate lower than that of the fabric and extends along the four sides of the bottom surface to connect the corner-corresponding portions.

Description

Cushion with cover

[0001] The present invention relates to a cushion with a cover.

[0002] Conventionally, a mattress cover has been known in which an upper cover covering the top side of the cushion body and a lower cover covering the bottom side can be connected and separated with a zipper to facilitate the attachment and detachment of the cushion body and cushion cover.

[0003] Patent No. 7045336

[0004] However, when joining or separating the upper cover and the lower cover, it is necessary to operate the fasteners provided around the entire side, which is time-consuming. To avoid this, it is possible to use a cover with a bottom opening, but this has the problem that the cushion cover is prone to slipping off.

[0005] In view of the above problems, the present invention aims to provide a cushion with a cover that can improve the ease of attaching and detaching the cover while also preventing the cover from slipping out of place.

[0006] The cushion with cover according to the present invention includes a rectangular parallelepiped cushion body and a cover that encases the cushion body, wherein the cover has fabric covering each side and top surface of the cushion body and a fixing member attached to the fabric, and an opening on the underside that can accommodate the cushion body, and the fixing member has corner-corresponding portions that correspond to each of the four corners of the bottom surface of the cushion body and hook onto the corresponding corner of the bottom surface to prevent misalignment, and connecting portions that are made of a material with a lower elongation rate than the fabric and extend along each of the four sides of the bottom surface to connect the corner-corresponding portions. This configuration makes it possible to achieve both improved ease of attachment and detachment of the cover and prevention of misalignment of the cover.

[0007] More specifically, the fixing member may be formed in a loop shape shorter than the perimeter of the bottom surface so as to include the corner corresponding portion and the connecting portion, and a gap may be provided between the corner corresponding portion and the corresponding corner of the bottom surface when viewed from below. Also, more specifically, the shape of the corner corresponding portion may be a hollow triangular pyramid with the base omitted.

[0008] More specifically, the cover may have a stretch-preventing member provided along the periphery of the top surface of the fabric. Furthermore, more specifically, the cover may have a second stretch-preventing member provided along the side surface of the fabric. Furthermore, more specifically, the opening may be located inside the periphery of the bottom surface of the fabric, and the cover may have a fourth fixing member provided along the opening.

[0009] More specifically, the elongation rate of the fixing member may be 0.1% or more and 15% or less. Furthermore, the horizontal compression rate of the cushion body may be 0.1% or more and 5% or less. Furthermore, the corner rigidity index of the cushion body may be 10 N or more and 150 N or less. Furthermore, the cover deformation index of the cover may be 10 mm or more and 150 mm or less. Furthermore, the size of the gap may be 5 mm or more and 50 mm or less.

[0010] According to the cushion with cover of the present invention, it is possible to improve the ease of attaching and detaching the cover while also preventing the cover from shifting.

[0011] 8A ; 8B , 8C , 8D , 8E , 8F , 8G , 8H , 8I , 8K ...

[0012] Each embodiment of the present invention will be described below with reference to the drawings. In the following description, the front-to-back, left-to-right, and up-to-down (thickness) directions (which are mutually perpendicular) for the cushion with cover are as shown in Fig. 1 etc. Note that the front-to-back, left-to-right, and up-to-down directions (which are mutually perpendicular) for the manufacturing device for a filament three-dimensional combined body, which will be described later, are as shown in Figs. 8A and 8B.

[0013] First Embodiment First, the first embodiment will be described. Fig. 1 is an exploded perspective view of a cushion with cover 1 according to the first embodiment. Fig. 2 is a perspective view of the cushion with cover 1 as viewed from the bottom side. The cushion with cover according to each embodiment, including the first embodiment, can be used for, for example, a mattress, a sofa bed, a couch bed, a sofa, and a chair.

[0014] The cushion with cover 1 has a cushion body 2 and a cover 5 that covers the cushion body 2. The cushion body 2 is formed of a rectangular parallelepiped three-dimensionally joined filaments. The three-dimensionally joined filaments are formed by three-dimensionally fusion-bonding a plurality of thermoplastic resin filaments. By using the three-dimensionally joined filaments, a cushion with cover 1 that does not easily become stuffy can be obtained.

[0015] The cushion body 2 has four side surfaces 21 (front, back, left, and right), a top surface 22, and a bottom surface 23. It is desirable to provide a high-density smooth surface layer on the cushion body 2. By providing the high-density smooth surface layer, it is possible to further increase the corner rigidity index, which will be described later. The high-density smooth surface layer and the method for manufacturing the three-dimensional filament bonded body will be described later.

[0016] The cushion body 2 is not limited to being formed as a single unit, but may be divisible into multiple pieces. For example, the cushion body 2 may be divisible into three pieces in the front-rear direction, or into two pieces in the left-right direction and into three pieces in the front-rear direction. The cushion body 2 may also be in the form of a rectangular parallelepiped three-dimensional filament assembly covered with an inner cover.

[0017] The cover 5 has a fabric 3 as a main body and an anti-stretch member 4 attached to the fabric 3. The fabric 3 covers each side surface 21 and top surface 22 of the cushion body 2. Specifically, the fabric 3 has four side surface portions 31 (front, back, left, and right), a top surface portion 32, and an opening 33. The side surface portions 31 and the top surface portion 32 form an outer shape of a hollow rectangular parallelepiped (excluding the lower surface), and an opening 33 that opens downward is provided on the lower side of the rectangular parallelepiped.

[0018] In this embodiment, the opening 33 is generally formed so that the lower ends of the four side surface portions 31 form the periphery. In the covered cushion 1, the cushion body 2 can be placed in or removed from the cover 5 through the opening 33, making it easy to attach and detach the cover 5.

[0019] As shown in FIG. 2 , the stretch-preventing member 4 has connecting portions 41 provided along the periphery of the opening 33 of the fabric 3 and corner-corresponding portions 42 provided near the corners of the opening 33. In this embodiment, the stretch-preventing member 4 is formed in a single loop shape that is shorter than the perimeter of the bottom surface 23, so as to include the corner-corresponding portions 42 and the connecting portion 41. The connecting portion 41 includes two extension portions 41A, one at the front and one at the rear, that extend in the left-right direction, and two extension portions 41B, one at the left and one at the rear, that extend in the front-to-rear direction. The corner-corresponding portions 42 are connected to the ends of adjacent connecting portions 41 in the circumferential direction. The corner-corresponding portions 42 can be considered to correspond to the four corners of the rectangular bottom surface 23, and the connecting portions 41 can be considered to correspond to the four sides of the bottom surface 23.

[0020] The corner corresponding portions 42 extend generally at an angle of 45° relative to the front-rear or left-right direction, and are arranged at four locations on each of the front left and right sides and the rear left and right sides so as to pass inside the corresponding corners of the bottom surface 23 when viewed from below. A gap α is provided between the corner corresponding portions 42 when viewed from below and the corresponding corners of the bottom surface 23.

[0021] With the cushion body 2 housed in the cover 5, as shown in Fig. 2, the connecting portion 41 is arranged along the periphery of the bottom surface 23 of the cushion body 2, and the corner corresponding portion 42 is arranged near the corner of the bottom surface 23. The stretch-preventing member 4 is a highly elastic member with a low stretch rate, and functions as a member that reduces stretching of the fabric 3 and also functions as a fixing member that hooks onto the corners of the bottom surface 23 of the cushion body 2 to prevent misalignment. The definition of stretch rate will be described later. The stretch-preventing member 4 has a lower stretch rate than the fabric 3 and is made of, for example, rubber or a tape-like string.

[0022] Fig. 3 is an explanatory diagram of the effect of the covered cushion 1. As shown in Fig. 3, when a force F1 (in this example, a force pulling the fabric 3 to the left) is generated to pull the fabric 3 of the cover 5, the corner-corresponding portion 42 hooks onto at least one of the four corners of the bottom surface 23 of the cushion body 2 (mainly two corners indicated by Z1 and Z2 in the example of Fig. 3), preventing displacement (i.e., fixing the corner in place). Therefore, when force F1 is applied, tension T is generated in the connecting portion 41, which generates a restoring force F2 (a force that returns the cover 5 to its original state).

[0023] Furthermore, because the connecting portions 41 are made of a material with a lower elongation rate than the fabric 3, a higher tension T is generated than when the elongation rate of the connecting portions 41 is the same as that of the fabric 3, and a higher restoring force F2 can be obtained. In this way, the corner corresponding portions 42 that hook onto the corners of the bottom surface 23 function as fulcrums that generate the restoring force F2, and the stretch prevention members 4 not only make it difficult for the cover 5 to shift, but also help to return the cover 5 to its original state even if it does shift.

[0024] It is desirable to appropriately set each parameter related to the covered cushion 1 as described below. First, the elongation rate of the elongation prevention member 4 is preferably 0.1% or more and 15% or less, and more preferably 3% or more and 10% or less.

[0025] Here, a method for measuring the elongation of the stretch prevention member 4 will be described with reference to Figure 4. The stretch prevention member 4 is cut to a length of 1100 mm to prepare a measurement sample. Two clamps C are used to fix both ends of the measurement sample with the clamps C so that the distance between the clamps C is 1 m. Next, the clamps C on both ends are pulled with a force FA of 10 N, and the length A (mm) of the measurement sample at this time is measured. Next, the clamps C on both ends are pulled with a force FA of 60 N, and the length B (mm) of the measurement sample at this time is measured, and the elongation (%) is calculated using the following formula: Elongation (%) = (length B - length A) / length A x 100

[0026] If the elongation rate is less than 0.1%, the stretch-preventing member 4 will be too hard, and there is a possibility that fingers will be pinched between the cover 5 and the cushion body 2 and injured when attaching or removing the cover 5. If the elongation rate exceeds 15%, the tension T will decrease when the covered cushion 1 is used, making it difficult to obtain a sufficient restoring force F2. Therefore, as described above, the elongation rate of the stretch-preventing member 4 is preferably 0.1% or more and 15% or less.

[0027] The total length of the stretch-preventing member 4 when the cushion body 2 is housed in the cover 5 is preferably longer than the natural length of the stretch-preventing member 4 when the cushion body 2 is not housed in the cover 5, and when an stretch-preventing member 4 with an elongation rate of 3% or more and 10% or less is used, the ratio of the length of the stretch-preventing member 4 when attached to the cover 5 to its natural length (stretch ratio) is preferably 1.5 times or more and 3 times or less. This makes it possible to obtain a higher restoring force F2 without impairing operability when attaching and detaching.

[0028] The compressibility of the cushion body 2 in the horizontal direction (the direction perpendicular to the up and down directions) is preferably 0.1% or more and 5% or less, and more preferably 0.5% or more and 3% or less. Here, a method for measuring the compressibility of the cushion body 2 will be described with reference to FIG. 5 .

[0029] The cushion body 2 is placed horizontally on a running saw and cut into a square with sides of 100 mm in plan view to prepare a measurement sample. Both ends of the measurement sample are sandwiched between metal plates P and compressed with a force FB of 10 N. The length (mm) of the measurement sample that has shrunk due to compression is measured, and the compression ratio (%) is calculated using the following formula: Compression ratio (%) = Shrinkage length / 100 × 100

[0030] If the compression rate is less than 0.1%, the cushion will be too hard, resulting in poor sleeping comfort. If the compression rate exceeds 5%, the tension T will decrease when the cushion 1 with cover is used, making it difficult to obtain a sufficient restoring force F2. Therefore, as described above, the horizontal compression rate of the cushion body 2 is preferably 0.1% or more and 5% or less. Note that by employing a three-dimensional filament bonded body as the cushion body 2 as in this embodiment, it is possible to set a high horizontal compression rate.

[0031] The corner rigidity index of the cushion body 2 is preferably 10 N or more and 150 N or less, and more preferably 20 N or more and 80 N or less. A method for measuring the corner rigidity index of the cushion body 2 will now be described with reference to Figure 6. The lower right portion of Figure 6 shows a schematic view of the vicinity of the weight Wt when viewed from above.

[0032] With the cover 5 covering the cushion body 2, a 30 kg weight Wt is placed near the corner-corresponding portion of the top surface of the fabric 3, and a thin wire Wr is fixed to the corner-corresponding portion of the top surface of the fabric 3. The weight Wt is cylindrical with a bottom diameter of 300 mm, and the gap β between the weight Wt and each of the two edges of the top surface of the fabric 3 is 100 mm. The wire Wr is pulled vertically upward, and the force (N) is measured when the corner-corresponding portion 42 of the stretch-preventing member 4 shifts upward, and this value is taken as the corner rigidity index.

[0033] If the corner rigidity index is less than 10 N, it becomes difficult to obtain a sufficient restoring force F2. If the corner rigidity index exceeds 150 N, it becomes difficult to remove the cover 5. Therefore, as described above, it is preferable that the corner rigidity index of the cushion body 2 is 10 N or more and 150 N or less.

[0034] The cover deformation index of the cover 5 is preferably 10 mm or more and 150 mm or less, and more preferably 20 mm or more and 100 mm or less. A method for measuring the cover deformation index will now be described with reference to FIG.

[0035] With the cover 5 covering the cushion body 2, the center of the longitudinal periphery of the top surface of the fabric 3 is pulled horizontally outward with a force FC of 50 N. The distance (mm) by which the center of the longitudinal periphery is displaced is measured, and this value is taken as the cover deformation index.

[0036] If the cover deformation index is less than 10 mm, it may be too hard and result in poor sleeping comfort. If the cover deformation index is more than 150 mm, it is difficult to obtain a sufficient restoring force F2. Therefore, as described above, the cover deformation index of the cover 5 is preferably 10 mm or more and 150 mm or less. In order to reduce the cover deformation index, for example, the fabric 3 may be made thicker.

[0037] Furthermore, the size of the aforementioned gap α is preferably 5 mm or more and 50 mm or less, and more preferably 10 mm or more and 25 mm or less. If the gap α is too small, there is a risk that the corner corresponding portion 42 will not be able to catch tightly on the vicinity of the corner of the bottom surface 23, whereas if the gap α is too large, there is a risk that it will be difficult to attach or detach the cushion body 2 to or from the cover 5.

[0038] Fig. 8A is a schematic diagram of a manufacturing apparatus 100 for a three-dimensionally bound filament body that can be used to manufacture the cushion body 2. Fig. 8B is a cross-sectional view taken along the line AA' of the manufacturing apparatus 100 shown in Fig. 8A.

[0039] The manufacturing apparatus 100 for a three-dimensionally combined filament body includes a molten filament supply section 110 that discharges a molten filament group MF consisting of a plurality of molten filaments with diameters in the range of 0.3 mm to 3 mm vertically downward, and a fusion bond forming section 120 that three-dimensionally entangles the molten filament group MF, fusion bonds the contact points, and then cools and solidifies the fusion bond to form a three-dimensionally combined filament body.

[0040] The molten filament supply unit 110 includes a pressure melting unit 111 (extruder) and a filament discharge unit (die) 112. The pressure melting unit 111 includes a material input unit 113 (hopper), a screw 114, a screw motor 115 that drives the screw 114, a screw heater (not shown), and multiple temperature sensors (not shown), and is internally formed with a cylinder 111a for transporting the thermoplastic resin or thermoplastic elastomer (hereinafter, these may be collectively referred to as "thermoplastic resin, etc.") supplied from the material input unit 113 while heating and melting it with the screw heater.

[0041] A screw 114 is rotatably housed within the cylinder 111a. A cylinder outlet 111b is formed at the downstream end of the cylinder 111a for discharging a thermoplastic resin or the like toward the filament discharge section 112. The heating temperature of the screw heater is controlled based on a detection signal from a temperature sensor provided in the molten filament supply section 110, for example.

[0042] The filament discharge section 112 includes a nozzle section 116, a die heater 118, and a plurality of temperature sensors (not shown), and is provided with a guide channel 112a formed therein to guide the molten thermoplastic resin or the like discharged from the cylinder discharge port 111b to the nozzle section 116.

[0043] The nozzle portion 116 is a thick metal plate having a substantially rectangular parallelepiped shape, and is provided below the filament discharge portion 112, which corresponds to the most downstream portion of the guide channel 112a. FIG. 8C shows an example of the configuration of the bottom surface of the nozzle portion 116. Thus, a plurality of nozzle openings 116a for discharging the molten filament are formed on the bottom surface of the nozzle portion 116. As an example, the nozzle openings 116a are arranged in a staggered pattern in the front-to-back and left-to-right directions, with the distance (pitch) between adjacent nozzle openings 116a being approximately 5 to 15 mm. In the example shown in FIG. 8C , the cross-sectional shape of the nozzle openings 116a is a circle with an inner diameter of 1 mm, and the distance (pitch) between adjacent nozzle openings 116a is 10 mm. However, the specific configuration of the nozzle openings 116a is not particularly limited.

[0044] Furthermore, the shape and inner diameter of each nozzle opening 116a, the spacing between adjacent nozzle openings 116a, or the proportion of the nozzle openings 116a on the underside of the nozzle section 116 (density of nozzle openings 116a) can be adjusted as appropriate according to the specifications of the three-dimensionally bonded filaments to be manufactured. This makes it possible to change the bulk density of the three-dimensionally bonded filaments 3DF formed by the manufacturing apparatus 100, or the shape and diameter of the filaments that make up the three-dimensionally bonded filaments 3DF, and ultimately to adjust the repulsive force of the three-dimensionally bonded filaments 3DF when compressed.

[0045] The fusion bond forming unit 120 includes a cooling water tank 123, an underwater take-up machine (a pair of slat conveyors) 124, a plurality of conveying rollers 125a to 125h, and a pair of receiving plates 121 that regulate the thickness of the filament three-dimensional bonded body. The receiving plate 121 is a metal plate having a bent portion including a flat inclined surface 121a that slopes downward and a flat vertical surface 121b that extends vertically downward from the lower end of the inclined surface 121a.

[0046] The receiving plate 121 guides the thickness direction ends of the molten filament group MF toward the center using the front and rear inclined surfaces 121 a, thereby reducing the front-to-rear dimension of the molten filament group MF to the distance between the front and rear vertical surfaces 121 b, smoothing the surface while increasing the density of the thickness direction ends of the molten filament group MF, and forming a high-density smooth surface layer. The density of the high-density smooth surface layer can be adjusted by changing the area (diameter and number of nozzle openings 116 a) of the nozzle openings 116 a located vertically above the inclined surfaces 121 a of the receiving plate 121.

[0047] A cooling water supply device 122 that supplies cooling water to the receiving plate 121 is provided near the upper end of the receiving plate 121. The cooling water tank 123 is a water tank for storing cooling water W. An underwater haul-off machine 124 and multiple transport rollers 125a to 125h are disposed inside the cooling water tank 123. The underwater haul-off machine 124 and multiple transport rollers 125a to 125h are driven by a drive motor (not shown), and the repulsive force of the three-dimensional filament assembly during compression can be adjusted by changing the speed of the underwater haul-off machine 124.

[0048] Examples of thermoplastic resins that can be used as materials for the filament three-dimensional bonded body include thermoplastic resins such as polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 66, polyvinyl chloride resin, and polystyrene resin, as well as thermoplastic elastomers such as styrene elastomers, vinyl chloride elastomers, olefin elastomers, urethane elastomers, polyester elastomers, nitrile elastomers, polyamide elastomers, and fluorine-based elastomers.

[0049] The thermoplastic resin or the like supplied from the material input unit 113 is heated and melted in the cylinder 111a and is then extruded, for example, by a screw 114, and supplied as the molten thermoplastic resin or the like from the cylinder outlet 111b to the guide channel 112a of the filament discharge unit 112. Thereafter, a molten filament group MF consisting of a plurality of molten filaments is discharged from each of the plurality of nozzle openings 116a of the nozzle unit 116 so as to move downward in translation.

[0050] The molten filament group MF (plurality of filaments made of thermoplastic resin) discharged from the nozzle portion 116 has its thickness (front-rear dimension) adjusted by the receiving plate 121 as described above, and is deflected by the buoyancy of the cooling water W in the cooling water tank 123, with each molten filament forming a random loop. The random loops are entangled three-dimensionally with adjacent random loops in a molten state, and in this three-dimensional entangled state, a three-dimensional filament bond 3DF is formed in which the contact points between the filaments are fusion-bonded.

[0051] The three-dimensional filament combined body 3DF is transported by an underwater take-up machine 124 and multiple transport rollers 125a-125h while being cooled by cooling water W in a cooling water tank 123, and is ultimately discharged outside the cooling water tank 123. The three-dimensional filament combined body 3DF continuously discharged in this manner is cut at appropriate intervals so that a plane perpendicular to the transport direction forms a cross section, thereby forming each cushion body. The cushion body thus formed has a high-density smooth surface layer formed in each portion corresponding to both ends in the thickness direction of the aforementioned molten filament group MF. By providing a high-density smooth surface layer, the horizontal compressibility and corner rigidity index of the cushion body can be increased.

[0052] In addition, as a method for forming a high-density smooth surface layer on a filament three-dimensional bonded body, a method can also be adopted in which a cut surface formed by cutting using a cutter or the like is heated and melted while being pressed with a pressing tool or machine to form a high-density smooth surface layer.

[0053] Second Embodiment Next, a second embodiment will be described. Fig. 9 is a perspective view of the covered cushion 1 according to the second embodiment, viewed from the bottom side, and the appearance of the corner corresponding portions 42 is schematically shown in the lower part. The difference from the first embodiment is the configuration of the four corner corresponding portions 42 in the stretch prevention member 4. Specifically, the corner corresponding portions 42 have a hollow triangular pyramid shape with the base omitted.

[0054] The corner-corresponding portion 42 has three flat portions 42a corresponding to the side surfaces of the triangular pyramid shape and an apex portion 42b corresponding to the apex of the triangular pyramid shape, and is made of, for example, artificial leather or silicone rubber. In this embodiment, the three flat portions 42a are each a right-angled isosceles triangle of the same size. In this embodiment, the apex portion 42b of the corner-corresponding portion 42 is positioned close to the corner of the cushion body 2, and the inner surfaces of the three flat portions 42a face and contact the side surface 21 and bottom surface 23 of the cushion body 2. This further improves the stability of the corner-corresponding portion 42 as a fulcrum that generates the restoring force F2 when a force such as the force F1 described above is applied to the fabric 3.

[0055] <Third Embodiment> Next, a third embodiment will be described. Fig. 10 is a perspective view of a cushion with cover 1 according to the third embodiment, as viewed from the top surface side. In this embodiment, as in the first embodiment, the cover 5 includes an anti-stretch member 4 including a connecting portion 41 and a corner corresponding portion 42. However, a difference from the first embodiment is that the cover 5 of this embodiment is provided with a sewn portion 6 that is sewn at a right angle when viewed in the vertical direction so that the thickness of the fabric 3 is increased near the corners.

[0056] The sewn portion 6 can be formed by sewing a piece of fabric or the like to the fabric 3 to increase thickness, spanning the edge where adjacent side portions 31 of the fabric 3 meet and covering the entire area near the edge of these side portions 31 (within a predetermined distance from the edge). The sewn portion 6 is L-shaped when viewed from the top and bottom, and may or may not be integrated with the stretch-preventing member 4. By providing such a sewn portion 6, that portion of the cover 5 is reinforced, further suppressing misalignment of the corner corresponding portion 42 and further improving the stability of the corner corresponding portion 42 as a fulcrum that generates the restoring force F2.

[0057] <Fourth embodiment> Next, a fourth embodiment will be described. Fig. 11 is a perspective view of a cushion with cover 1 according to the fourth embodiment, viewed from the top surface side. In this embodiment, a second stretch-preventing member 7 is added to the configuration of the third embodiment. That is, the cover 5 has the second stretch-preventing member 7 in addition to the stretch-preventing member 4. The second stretch-preventing member 7 has a single loop shape when viewed from above, and is provided on the outer surface of the fabric 3 along the periphery of the top surface portion 32 of the fabric 3. Note that the second stretch-preventing member 7 may also be provided on the inner surface of the fabric 3.

[0058] The second stretch-preventing member 7 can be made of, for example, rubber or a tape-like string, and the stretch percentage of the second stretch-preventing member 7 is preferably 0.1% or more and 15% or less, and more preferably 3% or more and 10% or less. According to the fourth embodiment, it is possible to further increase the restoring force F2 generated when a force such as the force F1 described above is applied to the fabric 3. Note that the configuration is not limited to the third embodiment, and the second stretch-preventing member 7 may be added to the configuration of the first embodiment, for example.

[0059] Fifth Embodiment Next, a fifth embodiment will be described. Fig. 12 is a perspective view of the cushion with cover 1 according to the fifth embodiment, viewed from the top surface side. In this embodiment, a third stretch-preventing member 8 is added to the configuration of the fourth embodiment. That is, the cover 5 has the third stretch-preventing member 8 in addition to the stretch-preventing member 4 and the second stretch-preventing member 7.

[0060] The third stretch-preventing member 8 has a single loop shape when viewed from above, and is provided along the front-to-back side surface portions 31A and the left-to-right side surface portions 31B of the fabric 3, and is provided on the outer surface of the fabric 3. It may also be provided on the inner surface of the fabric 3. The third stretch-preventing member 8 may be made of, for example, rubber or a tape-like string, and the stretch percentage of the second stretch-preventing member 7 is preferably 0.1% or more and 15% or less, and more preferably 3% or more and 10% or less.

[0061] 12, the third stretch-preventing member 8 is disposed on each of the left and right side surfaces 31A so as to extend in a straight line from the lower rear end to the upper end in the center in the front-rear direction, and then from there to the lower front end. Also, the third stretch-preventing member 8 is disposed on each of the front and rear side surfaces 31B so as to extend in a straight line from the lower left end to the upper end in the center in the left-right direction, and then from there to the lower right end.

[0062] The third stretch-preventing member 8 may or may not be integrated with the stretch-preventing member 4. According to the fifth embodiment, it is possible to further increase the restoring force F2 that is generated when a force such as the force F1 described above is applied to the fabric 3. The third stretch-preventing member 8 may be added to the configuration of the first embodiment, for example, and is not limited to the third embodiment.

[0063] Sixth Embodiment Next, a sixth embodiment will be described. Fig. 13 is a perspective view of the cushion with cover 1 according to the sixth embodiment, viewed from the bottom side. This embodiment differs from the first embodiment in that a fourth stretch-preventing member 9 is added. That is, the cover 5 has the fourth stretch-preventing member 9 in addition to the stretch-preventing member 4. In this embodiment, unlike the first embodiment, the edge of the opening 33 in the fabric 3 is located more inward than the periphery of the bottom surface of the fabric 3.

[0064] The fourth stretch-preventing member 9 has a single loop shape when viewed from below, and is provided along the edge of the opening 33. The fourth stretch-preventing member 9 is a low-elasticity member with a higher stretch rate than the stretch-preventing member 4, making it easier to store the cushion body 2 in the cover 5. According to this embodiment, it is possible to further increase the restoring force F2 that is generated when a force such as the force F1 described above is applied to the fabric 3. Note that the fourth stretch-preventing member 9 may be added to the configuration of the fifth embodiment, for example, and is not limited to the first embodiment.

[0065] Seventh Embodiment Next, a seventh embodiment will be described. Fig. 14 is a perspective view of the cushion with cover 1 according to the seventh embodiment, viewed from the bottom side. In the stretch prevention member 4 of this embodiment, the connecting portion 41 is provided so as to form a single loop when viewed from below, so as to generally coincide with the entire periphery of the bottom surface 23. The corner corresponding portions 42 extend at an angle of 45° relative to the front-rear direction or the left-right direction, and are provided corresponding to each of the four corners of the bottom surface 23 of the cushion body 2, so that both ends are connected at a predetermined distance Y from the corner positions of the connecting portion 41.

[0066] Even if the corner corresponding portion 42 is configured as in this embodiment, it is possible to make the corner corresponding portion 42 function as a fulcrum that generates a restoring force F2 when a force such as the force F1 described above is applied to the fabric 3. The above-mentioned predetermined distance Y is appropriately set so that the corner corresponding portion 42 functions as such a fulcrum.

[0067] <Others> As described above, the cushion with cover 1 of each embodiment includes a rectangular parallelepiped cushion body 2 and a cover 5 that covers the cushion body 2. The cover 5 has fabric 3 that covers each side surface 21 and top surface 22 of the cushion body 2 and stretch-preventing members 4 (fixing members) attached to the fabric 3, and has an opening 33 on the underside that can accommodate the cushion body 2. The stretch-preventing members 4 also include corner-corresponding portions 42 that correspond to each of the four corners of the bottom surface 23 of the cushion body 2 and hook onto the corresponding corners of the bottom surface 23 to prevent misalignment, and connecting portions 41 that are members with a lower stretch rate than the fabric 3 and extend along each of the four sides of the bottom surface 23 to connect the corner-corresponding portions 42 to each other. Therefore, the cushion with cover 1 can achieve both improved attachment and removal of the cover 5 and prevention of misalignment of the cover 5.

[0068] Although the embodiments of the present invention have been described above, the configuration of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. In other words, the above embodiments are illustrative in all respects and should be considered not to be limiting. The technical scope of the present invention is defined by the claims, not by the description of the above embodiments, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0069] REFERENCE SIGNS LIST 1 Cushion with cover 2 Cushion body 21 Side surface 22 Top surface 23 Bottom surface 3 Fabric 31 Side portion 32 Top surface portion 33 Opening 4 Stretch-preventing member 41 Connecting portion 42 Corner-corresponding portion 5 Cover 6 Sewn portion 7 Second stretch-preventing member 8 Third stretch-preventing member 9 Fourth stretch-preventing member

Claims

1. A cushion with cover including a rectangular parallelepiped cushion body and a cover which encases the cushion body, wherein the cover has fabric covering each side and top surface of the cushion body and a fixing member attached to the fabric, with an opening on the underside which is capable of accommodating the cushion body, and the fixing member has corner corresponding portions which correspond to each of the four corners of the bottom surface of the cushion body and hook onto the corresponding corners of the bottom surface to prevent misalignment, and connecting portions which are made of a material with a lower stretch rate than the fabric and extend along each of the four sides of the bottom surface to connect the corner corresponding portions together.

2. The cushion with cover described in claim 1, characterized in that the fixing member is formed in a loop shape shorter than the perimeter of the bottom surface so as to include the corner-corresponding portion and the connecting portion, and a gap is provided between the corner-corresponding portion when viewed from below and the corresponding corner of the bottom surface.

3. The cushion with cover according to claim 1, characterized in that the shape of the corner corresponding portion is a hollow triangular pyramid with the base omitted.

4. A cushion with a cover as described in any one of claims 1 to 3, characterized in that the elongation rate of the fixing member is 0.1% or more and 15% or less.

5. A cushion with a cover as described in any one of claims 1 to 3, characterized in that the horizontal compression rate of the cushion body is 0.1% or more and 5% or less.

6. A cushion with a cover as described in any one of claims 1 to 3, characterized in that the corner rigidity index of the cushion body is 10N or more and 150N or less.

7. A cushion with a cover as described in any one of claims 1 to 3, characterized in that the cover deformation index of the cover is 10 mm or more and 150 mm or less.

8. The cushion with cover according to claim 2, characterized in that the size of the gap is 5 mm or more and 50 mm or less.

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