Mattress

Abstract

A mattress M according to the present invention is composed of a bonded body in which a large number of filaments are three-dimensionally bonded. The mattress M has, on the lower surface thereof, a plurality of first grooves 31 and a plurality of second grooves 32 which are continuously formed over the entire shorter direction and extend from the lower surface to the upper surface. The width of the opening of the first groove 31 is 8 mm or less. The width of the opening of the second groove 32 is between 10 mm and 50 mm (both inclusive). The inner wall surfaces of the first groove 31 and the second groove 32 are composed of filaments with no cut surface. The filament density in the vicinity of the inner wall surfaces of the first groove 31 and the second groove 32 is greater than the filament density at the center part in the thickness direction of the mattress M.

Description

mattress

[0001] The present invention relates to a mattress constructed of a three-dimensional filament assembly.

[0002] As a cushioning material that overcomes the drawbacks of metal springs and urethane foam, which require a lot of effort to recycle, attention has been drawn to three-dimensionally fused filament-bonded filaments (three-dimensional network structures) made of thermoplastic elastomers. This cushioning material has the advantages of being easy to recycle, not becoming stuffy, and being washable.

[0003] Patent Document 1 discloses a bed cushion made of a three-dimensional filament bond, in which multiple continuous grooves are formed that penetrate the cushion in the short direction by cutting the cushion from the bottom to the top while applying heat, and the continuous grooves expand when the three-dimensional filament bond is bent upward.

[0004] Patent document 2 discloses a method for forming recesses in the manufacturing process of a mattress made of a three-dimensional filament assembly by sinking protrusions at required intervals into one side of the three-dimensional filament assembly before it hardens in a cooling tank.

[0005] Patent Document 3 discloses a three-dimensional filament assembly having a V-shaped groove formed on the lower surface.

[0006] JP 2006-6924 A JP 2000-23799 A JP 2020-45589 A

[0007] In the bed cushion disclosed in Patent Document 1, as the number of head-up and gag-up movements increases, the cut points on the inner wall of the continuous grooves may come loose, reducing the strength of the three-dimensional filament assembly. There is also a risk of reduced resilience at the cut points. In the mattress manufacturing method disclosed in Patent Document 2, it is difficult to narrow the width of the recesses once the three-dimensional filament assembly has begun to solidify, and attempting to narrow the spacing between the recesses may result in the mattress being compressed by the multiple recesses, reducing the width of the mattress. The V-shaped grooves formed in the three-dimensional filament assembly disclosed in Patent Document 3 act as air guide channels and are formed continuously throughout the entire longitudinal direction of the mattress.

[0008] The object of the present invention is to make it easier for the mattress to bend convexly upward (mountain fold) and convexly downward (valley fold) when it is swaged up, and to prevent the three-dimensional filament bonds on the inner wall surface of the continuous groove formed on the underside of the mattress from coming undone even if the mattress is swaged up many times, thereby preventing a decrease in the strength and resilience of the mattress and ensuring high durability.

[0009] One aspect of the present invention that achieves the above-mentioned object is a mattress constructed of a composite body in which a large number of filaments are bonded in three dimensions, and has a plurality of first grooves and a plurality of second grooves formed continuously on the underside of the mattress across the entire short side direction, extending from the bottom surface to the top surface, the width of the opening of the first groove being 8 mm or less, the width of the opening of the second groove being 10 mm or more and 50 mm or less, the inner wall surfaces of the first grooves and second grooves being constructed of filaments without cut surfaces, and the filament density near the inner wall surfaces of the first grooves and second grooves being greater than the filament density in the center of the thickness direction of the mattress.

[0010] In the mattress having the above configuration, it is preferable that the cross section of the first groove perpendicular to the short side direction is rectangular.

[0011] In the mattress having the above configuration, it is preferable that the cross section of the second groove perpendicular to the short side direction is a V-shape whose width continuously narrows from the lower surface to the upper surface.

[0012] In the mattress having the above configuration, the first grooves are preferably formed at intervals in the range of 10 mm to 50 mm.

[0013] In the mattress having the above configuration, the intervals at which the second grooves are formed are preferably in the range of 5 mm to 20 mm.

[0014] The mattress according to the present invention is easily bent in mountain and valley folds when it is raised up. Even if the number of times it is raised up increases, the three-dimensional bonded filaments on the inner wall surface of the continuous groove formed on the underside of the mattress do not come undone, and the decrease in strength and resilience of the mattress is suppressed, resulting in high durability.

[0015] 6 is a perspective view showing one embodiment of a bed using a mattress according to the present invention; FIG. 7 is an enlarged view of a first groove; FIG. 8 is an enlarged view of a second groove; FIG. 9 is a view of the bed in a base state; FIG. 10 is a view of the bed in a gagged-up state; FIG. 11 is a conceptual diagram showing an example of a manufacturing apparatus for a filament three-dimensional bonded body; FIG. 12 is a cross-sectional view of the manufacturing apparatus shown in FIG. 6 along line A-A; FIG. 13 is a bottom view of a nozzle portion; FIG. 14 is a perspective view of a chute; FIG. 15 is a view of the chute as seen from a second direction; FIG. 16 is an enlarged view of another embodiment of a first groove; FIG. 17 is an enlarged view of another embodiment of a second groove.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the terms "longitudinal direction," "transverse direction," and "vertical direction" refer to the longitudinal direction, transverse direction, and vertical direction shown in Fig. 1. Furthermore, unless otherwise specified, "to" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits.

[0017] (Bed) Figure 1 is a perspective view showing one embodiment of a bed using a mattress according to the present invention. The bed B shown in Figure 1 comprises a bed base 41 that is rectangular in plan view, a flat headboard 42 that protrudes vertically upward from the head end of the bed base 41 in the longitudinal direction, and a mattress M placed on the bed base 41. The bed base 41 has a plurality of bottoms that support the mattress M. Specifically, the bed base 41 has a back bottom 411 that corresponds to the back of a user in a supine position, a central bottom 412 that corresponds to the buttocks, thigh bottoms 413 that correspond to the thighs, and lower leg bottoms 414 that correspond to the lower legs (see Figures 4 and 5). As will be described later, the bed base 41 can be changed into a basic state in which the four bottoms 411 to 414 are horizontal, a back-raised state in which the back bottom 411 is raised, a leg-raised state in which the thigh bottom 413 and lower leg bottom 414 are raised in a convex shape, and a gag-up state in which the back-raised state and the leg-raised state are performed simultaneously.

[0018] (Mattress M) The mattress M is composed of a three-dimensional filament bonded body TDF (shown in Figures 2 and 3) in which a large number of filaments are bonded in three dimensions, and is a rectangular parallelepiped in a plan view. Three first grooves 31 are formed continuously over the entire width direction on the underside of the mattress M in a portion corresponding to the buttocks of a user lying supine on the mattress M. Furthermore, three second grooves 32 are formed continuously over the entire width direction on the underside of the mattress M in a portion corresponding to the knees of a user lying supine on the mattress M.

[0019] (First Groove) FIG. 2 shows an enlarged view of the first groove 31. As shown in FIG. 2, the first groove 31 has the same longitudinal width from the lower surface to the upper surface of the mattress M, i.e., it is a rectangular groove when viewed from the short side of the mattress M. The opening width W1 of the first groove 31 is 8 mm or less. The first groove 31 is a groove provided in a portion corresponding to the buttocks of a user lying on the mattress M, i.e., a portion where the mattress M becomes a valley fold when the bed B is in a back-raised position. When the mattress M becomes a valley fold, the opening of the first groove 31 expands. Therefore, if the opening width of the first groove 31 is greater than 8 mm, the resilience and strength of the portion of the mattress M where the first groove 31 is formed (the portion of the mattress M corresponding to the buttocks) may be reduced. The opening width of the first groove 31 is preferably in the range of 0.5 mm to 2 mm. There is no particular limitation on the depth D1 of the first groove 31, but it is preferably in the range of 30% to 60% of the thickness of the mattress M. If the depth D1 of the first grooves 31 is less than 30% of the thickness of the mattress M, the effect of making the mattress easier to bend will not be fully achieved if the thickness of the mattress M is 100 mm or more. If the depth D1 of the first grooves 31 exceeds 60% of the thickness of the mattress M, the mattress M will be more likely to distort when bent. There are no particular restrictions on the spacing S1 between the first grooves 31, but a range of 10 mm to 50 mm is usually preferred. There are no restrictions on the number of first grooves 31 formed, and this may be determined appropriately taking into account the thickness of the mattress M, the valley fold angle, etc.

[0020] (Second Groove) FIG. 3 shows an enlarged view of the second groove 32. As shown in FIG. 3, the second groove 32 has a V-shape whose longitudinal width continuously narrows from the lower surface to the upper surface of the mattress M. The width W2 of the opening of the second groove 32 is 10 mm to 50 mm. The second groove 32 is provided in a portion corresponding to the knees of a user lying on the mattress M, i.e., in a portion where the mattress M folds in a mountain-like shape when the bed B is in a foot-raised position. When the mattress M folds in a mountain-like shape, the opening of the second groove 32 narrows. Therefore, if the width W2 of the opening of the second groove 32 is smaller than 10 mm, the opposing edges of the opening of the second groove 32 may come into pressure contact when the mattress M folds in a mountain-like shape, making it difficult to fold the mattress M. On the other hand, if the width W2 of the opening of the second groove 32 is larger than 50 mm, the resilience and strength of the portion of the mattress M where the second groove 32 is formed (the portion of the mattress M corresponding to the knees) may be reduced. There is no particular limitation on the depth D2 of the second grooves 32, but it is preferably in the range of 30% to 60% of the thickness of the mattress M. If the depth D2 of the second grooves 32 is less than 30% of the thickness of the mattress M, the effect of making the mattress easier to bend will not be fully achieved when the thickness of the mattress M is 100 mm or more. If the depth D2 of the second grooves 32 exceeds 60% of the thickness of the mattress M, the mattress M will be more likely to distort when bent. There is no particular limitation on the formation spacing S2 of the second grooves 32, but it is usually preferable that it be in the range of 5 mm to 20 mm. There is no particular limitation on the number of second grooves 32 formed, and it may be determined appropriately taking into account the thickness of the mattress M, the mountain fold angle, etc.

[0021] 2 and 3, a high-density layer 35 having a higher filament density than the central portion in the thickness direction is formed in the vicinity of the upper and lower surfaces of the mattress M, including the inner wall surfaces of the first grooves 31 and the second grooves 32. The thickness of the high-density layer 35 is usually in the range of 1 mm to 3 mm. A method for forming the high-density layer 35 will be described later.

[0022] (Three-Dimensional Filament Bonding Structure) The three-dimensional filament bonding structure TDF (see FIG. 6) is an elastic member obtained by three-dimensionally fusion-bonding molten filaments of thermoplastic resin. During the manufacturing process of the three-dimensional filament bonding structure TDF, molten thermoplastic resin is extruded vertically downward from a horizontally arranged nozzle 17 (shown in FIGS. 6 and 8). This causes molten filaments with a cross-sectional diameter of approximately 1 mm to fall into cooling water, where the buoyancy of the water causes loops to form. At the same time, the looped molten filaments are three-dimensionally fusion-bonded to each other, resulting in the three-dimensional filament bonding structure TDF. The thickness of the molten filaments is controlled by a pair of chutes 5a, 5b (see FIG. 9). At this time, a high-density layer 35, in which the filament density is higher than that of the central portion in the thickness direction, is formed on both thickness-wise side surfaces (top and bottom surfaces) including the inner wall surfaces of the first groove 31 and the second groove 32. The manufacturing method of such a three-dimensional filament bonding structure TDF will be described later.

[0023] The thickness of the three-dimensional filament bonded body TDF in the vertical direction is preferably in the range of 100 mm to 250 mm. In addition, the filament diameter (cross-sectional diameter) of the three-dimensional filament bonded body TDF is preferably in the range of 0.5 mm to 3 mm, and the bulk density is preferably 30 kg / m ３ ~150 kg / m ３ By forming high density layers 35 on both sides in the thickness direction, in which the density of the filaments is higher than that in the central portion in the thickness direction, and by keeping the thickness, filament diameter, and bulk density within the above ranges, the water drainage and drying properties of the filament three-dimensional bonded body TDF are not impaired, and a decrease in strength and resilience is suppressed, resulting in high durability.

[0024] The bulk density of the filament three-dimensional bonded body TDF can be measured, for example, by a measurement method using a rectangular parallelepiped measurement sample. In this measurement method, first, the mass W (kg) of the measurement sample and the size (m) of the measurement sample in each direction (vertical, horizontal, and height directions) are measured. In addition, the volume V (m) of the measurement sample is calculated by multiplying the size (m) of the measurement sample in each direction (vertical, horizontal, and height directions).３ ) is calculated. ３ ) is the mass W (kg) of the measurement sample and the volume V (m ３ ) is calculated by dividing by

[0025] (Usage of the mattress M) Figure 4 shows the basic state in which the four bottom parts 411 to 414 of the bed B are horizontal, and Figure 5 shows the up-close state in which the back bottom part 411 is raised and the thigh bottom part 413 and the lower leg bottom part 414 are raised convexly. When the bed B changes from the basic state to the up-close state, the buttocks-corresponding portion of the mattress M is valley-folded, and the first groove 31 on the underside of the mattress M is deformed in a direction that widens the opening, so that the rectangular first groove 31 becomes V-shaped. At the same time, the knees-corresponding portion of the mattress M is mountain-folded, and the second groove 32 on the underside of the mattress M is deformed in a direction that narrows the opening, so that the V-shaped second groove 32 becomes rectangular or linear. This deformation of the first groove 31 and the second groove 32 makes it easy to perform the valley fold and mountain fold of the mattress M.

[0026] Conversely, when the bed B changes state from the raised state to the basic state, the first groove 31 changes from a V-shape with an opening width widened to a rectangular shape, and the second groove 32 changes from a rectangular shape with an opening width narrowed to a V-shape, and the mattress M smoothly changes to the basic state.

[0027] (Method of manufacturing three-dimensionally bound filaments) The mattress M according to the present invention can be manufactured, for example, as follows. Fig. 6 is a conceptual diagram of a manufacturing apparatus 1 for a three-dimensionally bound filament TDF. Fig. 7 is a cross-sectional view of the manufacturing apparatus 1 shown in Fig. 6 taken along line A-A.

[0028] The manufacturing apparatus 1 for a three-dimensionally combined filament body TDF includes a molten filament supply unit 10 that discharges a molten filament group MF consisting of a large number of molten filaments with diameters of 0.5 mm to 3 mm vertically downward, a pair of chutes (guide members) 5a, 5b that receive both ends of the molten filament group MF in a first direction and guide them toward the center of the molten filament group MF in the first direction, in other words, that move the molten filament group MF in a direction that reduces its thickness in the first direction, cooling water supply units 4a, 4b that supply cooling water to the upper parts of the chutes 5a, 5b, and a fusion bond forming unit 20 that three-dimensionally entangles the molten filament group MF and simultaneously fusion-bonds the contact points, and then cools and solidifies the fusion bond forming unit 20 to form a three-dimensionally combined filament body TDF.

[0029] (Molten Filament Supply Section) The molten filament supply section 10 includes a pressure melting section (extruder) 11 and a filament discharge section (die) 12. The pressure melting section 11 includes a cylinder 11a, a screw 14 rotatably housed in the cylinder 11a, a screw motor 15 that drives the screw 14, a heater 16 that heats the cylinder 11a, a material input section (hopper) 13 for inputting thermoplastic resin into the cylinder 11a, and multiple temperature sensors (not shown). The thermoplastic resin supplied from the material input section 13 is heated and melted by the heater 16 and transported forward by the screw 14.

[0030] A cylinder outlet 11b is formed at the front end of the cylinder 11a for discharging the thermoplastic resin toward the filament discharge section 12. The heating temperature of the heater 16 is controlled based on a detection signal from a temperature sensor provided in the molten filament supply section 10, for example.

[0031] The filament discharge section 12 includes a nozzle section 17, a die heater 18, and a plurality of temperature sensors (not shown). A guide channel 12a is formed inside the filament discharge section 12 to guide the molten thermoplastic resin discharged from the cylinder outlet 11b to the nozzle section 17.

[0032] The nozzle section 17 is a thick metal plate having a substantially rectangular parallelepiped shape and formed with a large number of nozzle holes 17a (shown in FIG. 8), and is provided below the filament discharge section 12, which corresponds to the most downstream portion of the guide channel 12a. The large number of nozzle holes 17a formed in the nozzle section 17 will be described later with reference to FIG. 8.

[0033] A plurality of die heaters 18 (six die heaters 18a to 18f in the example shown in FIG. 7) are provided in the left-right direction and heat the guide channel 12a of the filament discharge section 12. The heating temperature of the die heater 18 is controlled based on a detection signal from a temperature sensor (not shown) provided in the filament discharge section 12, for example.

[0034] Examples of thermoplastic resins that can be used as materials for the filament three-dimensional bonded body TDF include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 66, polyvinyl chloride resins, and polystyrene resins, 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.

[0035] The thermoplastic resin supplied from the material input unit 13 is heated and melted in the cylinder 11a, and is extruded by the screw 14, and is supplied as molten thermoplastic resin from the cylinder outlet 11b to the guide channel 12a of the filament discharge unit 12. Thereafter, molten filaments are discharged downward from each of the many nozzle holes 17a of the nozzle unit 17, and a molten filament group MF is formed.

[0036] (Fusion Bond Forming Section) The fusion bond forming section 20 uses the buoyancy of water to form loops of molten filaments, while simultaneously bringing the molten filaments into contact with each other due to the bending that occurs during loop formation. The fusion bond forming section 20 fuses the contact points and then cools and solidifies to form a three-dimensional filament bond TDF. The fusion bond forming section 20 includes a cooling water tank 23, a pair of conveyors 24a, 24b, and multiple transport rollers 25a-25h. The cooling water tank 23 is a water tank for storing cooling water. Inside the cooling water tank 23, a pair of conveyors 24a, 24b and multiple transport rollers 25a-25h are disposed. The pair of conveyors 24a, 24b and multiple transport rollers 25a-25h are driven by a drive motor (not shown).

[0037] (Nozzle portion) Fig. 8 is a bottom view of the nozzle portion 17. The nozzle portion 17 is formed with a large number of nozzle holes 17a for discharging the molten filament group MF. In the example of this embodiment, the cross-sectional shape of the nozzle holes 17a is a circle with an inner diameter of 1 mm, and the distance (pitch) between adjacent nozzle holes 17a is 10 mm. However, the shape and inner diameter of the nozzle holes 17a, the spacing between adjacent nozzle holes 17a, and the arrangement pattern of each nozzle hole 17a can be adjusted as appropriate based on the specifications of the filament three-dimensional combined body TDF to be manufactured.

[0038] (Chute) Fig. 9 is a schematic perspective view of the pair of chutes 5a, 5b shown in Fig. 6. The pair of chutes 5a, 5b receive both ends in the first direction of the molten filament group MF supplied from the molten filament supply unit 10, guide them toward the center of the molten filament group MF in the first direction, and shift the molten filament group MF in a direction that reduces the thickness in the first direction, thereby adjusting the thickness in the first direction of the molten filament group MF and, ultimately, the thickness in the first direction of the three-dimensional combined filament body TDF.

[0039] The pair of chutes 5a, 5b are arranged opposite each other at a predetermined distance in the first direction. Specifically, the pair of chutes 5a, 5b are arranged symmetrically with respect to a virtual plane VP (shown in FIG. 10 ) that includes the second direction and the supply direction. The pair of chutes 5a, 5b have inclined portions 51a, 51b that extend toward the opposing chute as they move downstream in the supply direction of the molten filament group MF, and parallel portions 52a, 52b that connect to the downstream ends of the inclined portions 51a, 51b and extend parallel to the supply direction of the molten filament group MF and downstream in the supply direction. The inclined portions 51a, 51b and the parallel portions 52a, 52b are integrally formed, for example, by bending a plate-shaped member. The chute 5a further has three first protrusions 53 and three second protrusions 54 for forming first grooves 31 and second grooves 32 in the molten filament group MF. The first protrusions 53 and the second protrusions 54 are preferably formed separately from the inclined portion 51 a and the parallel portion 52 a, and are removably fixed to the inclined portion 51 a and the parallel portion 52 a by adhesive, magnetic attachment, screw fastening, etc. This is because the shapes and formation positions of the first grooves 31 and the second grooves 32 can be changed depending on the size and shape of the mattress M.

[0040] Each of the first protrusions 53 has a predetermined width in the second direction (substantially the same as the opening width of the first groove 31), is plate-shaped and extends in the supply direction, and has a main body 531 that protrudes perpendicularly inward from the inner wall of the parallel portion 52a of the chute 5a, and a ridge 532 that has a triangular cross section and extends from the upper edge of the main body 531 to a position halfway up the inclined portion 51a of the chute 5a at an angle that is gentler than the angle of inclination of the inclined portion 51a, the main body 531 and the ridge 532 being molded integrally. The formation interval of the first protrusions 53 in the second direction is the formation interval of the first grooves 31.

[0041] Each of the second protrusions 54 has a predetermined width in the second direction (substantially the same as the opening width of the second groove 32), is triangular prism-shaped and extends in the supply direction, and has a main body 541 that protrudes perpendicularly inward from the inner wall of the parallel portion 52a of the chute 5a, and a ridge portion 542 that has a triangular cross section and extends from the upper edge of the main body 541 to a position halfway along the inclined portion 51a of the chute 5a at an angle that is gentler than the angle of inclination of the inclined portion 51a, the main body 541 and the ridge portion 542 being molded integrally. The formation interval of the second protrusions 54 in the second direction is the formation interval of the second grooves 32.

[0042] The materials for the inclined portions 51 a, 51 b, the parallel portions 52 a, 52 b, the first projections 53, and the second projections 54 are not particularly limited as long as they have predetermined heat resistance, rust prevention, processability, etc. Examples of such materials include metals such as stainless steel, aluminum, and copper, and heat-resistant resins such as polycarbonate. Among these, metal materials such as stainless steel and copper are preferably used.

[0043] The inclined portions 51a, 51b receive both ends of the molten filaments MF in the first direction and guide them toward the center of the molten filaments MF in the first direction. The first protrusions 53 and the second protrusions 54 distribute the molten filaments MF received by the inclined portion 51a of the chute 5a to both sides in the second direction using the ridge portions 532, 542, thereby forming the molten filaments MF into the precursor shapes of the first grooves 31 and second grooves 32. The parallel portions 52a, 52b adjust the thickness of the molten filaments MF in the first direction, and therefore the thickness of the three-dimensional filament bond TDF in the first direction. Through this series of actions, a high-density layer 35 having a higher filament density than the central portion in the thickness direction is formed to a layer thickness of 1 mm to 3 mm on both side surfaces in the first direction (upper and lower surfaces in the thickness direction) including the inner wall surfaces of the first grooves 31 and second grooves 32.

[0044] Cooling water is supplied from cooling water supply units 4a and 4b to the surfaces of the pair of chutes 5a and 5b to form a cooling water film, preventing the molten filament group MF from fusing to the chute surface. To allow the cooling water supplied to the surfaces of the pair of chutes 5a and 5b to spread over the entire surfaces of the chutes 5a and 5b and form a uniform cooling water film, for example, a method of providing a continuous hydrophilic layer, a sandblasted layer (a surface layer on which fine irregularities are formed) or a grooved layer (a surface layer on which a plurality of fine grooves are formed) on the surfaces of the chutes 5a and 5b (including the first projections 53 and the second projections 54), or a method of covering the surfaces of the chutes with a water-permeable sheet such as bleached paper can be used.

[0045] In addition, from the viewpoint of reliably directing cooling water to the upstream ends of the first protrusions 53 and the second protrusions 54 in the cooling water supply direction, a cooling water passage (narrow groove) may be formed on the surface of the chute 5a, extending from the cooling water supply section 4a to the upstream ends of the first protrusions 53 and the second protrusions 54 in the cooling water supply direction.

[0046] (Cooling Water Supply Unit) The cooling water supply units 4a, 4b supply cooling water evenly and continuously to the inclined portions 51a, 51b of the chutes 5a, 5b. The cooling water supply units 4a, 4b are provided above the upper ends of the chutes 5a, 5b, spanning substantially the entire area of ​​the chutes 5a, 5b in the second direction. Note that the cooling water supplied to the chutes 5a, 5b by the cooling water supply units 4a, 4b may be, for example, water supplied from outside the manufacturing apparatus 1, or a portion of the cooling water in the cooling water tank 23.

[0047] (Formation of three-dimensional filament bond TDF) The molten filament group MF discharged from the nozzle portion 17 is adjusted in size in the first direction (thickness direction) by the chutes 5a and 5b, and then bends due to the buoyancy of the cooling water in the cooling water tank 23, and each molten filament therein forms a random loop. The random loops are three-dimensionally entangled with adjacent random loops in a molten state, and the contact points are fused and bonded to form a three-dimensional bond of filaments.

[0048] Thereafter, the combined body is transported by a pair of conveyors 24a, 24b and a plurality of transport rollers 25a to 25h while being cooled by cooling water in the cooling water tank 23, and is discharged as a three-dimensional combined filament body TDF out of the cooling water tank 23. In this way, a three-dimensional combined filament body TDF is manufactured.

[0049] The three-dimensional filament bond TDF thus produced is cut in the second direction (longitudinal direction of the mattress M) at a predetermined length in the supply direction (short direction of the mattress M) to form the mattress M.

[0050] (Other Modifications) Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the appended claims.

[0051] In the above-described embodiment, the cross-sectional shape of the first groove 31 perpendicular to the short side direction of the mattress M was rectangular, but it may also be, for example, an inverted trapezoid shape in which the width W1 of the opening is narrower than the width of the bottom, as shown in Figure 11(a), or a shape in which an arc is connected to the bottom of a rectangle, as shown in the same figure (b).

[0052] In the above-described embodiment, the cross-sectional shape of the second groove 32 perpendicular to the short side direction of the mattress M was V-shaped, but it may also be a trapezoidal shape in which the width W2 of the opening is wider than the width of the bottom surface, as shown in Figure 12(a), or a shape in which an arc is connected to the bottom of the trapezoid, as shown in the same figure (b).

[0053] In addition, in the above-described embodiment, the first groove 31 and the second groove 32 are formed only in the direction from the lower surface to the upper surface of the mattress M so as to prevent the user's limbs, etc. from falling into the grooves of the mattress M, but the first groove 31 or the second groove 32 may be formed only in the direction from the upper surface to the lower surface of the mattress M as long as it does not deviate from the spirit of the present invention.

[0054] The mattress M according to the present invention is easily bent in mountain and valley folds when it is raised up. Even if the number of times it is raised up increases, the three-dimensional filament bonds on the inner wall surfaces of the continuous grooves formed on the underside of the mattress M do not come undone, and the decrease in the strength and resilience of the mattress M is suppressed, resulting in high durability.

[0055] M Mattress S1 Formation interval of first groove S2 Formation interval of second groove W1 Width of opening of first groove W2 Width of opening of second groove 31 First groove 32 Second groove 35 High density layer TDF Three-dimensional filament bond

Claims

1. A mattress constructed from a composite of numerous filaments bonded three-dimensionally, the mattress having a plurality of first grooves and a plurality of second grooves formed continuously across the entire short side of the underside of the mattress from the bottom to the top, the width of the opening of the first grooves being 8 mm or less, the width of the opening of the second grooves being 10 mm or more and 50 mm or less, the inner wall surfaces of the first grooves and second grooves being made of filaments with no cut surfaces, and the filament density near the inner wall surfaces of the first grooves and second grooves being greater than the filament density at the center of the mattress in the thickness direction.

2. The mattress according to claim 1, wherein the cross section of the first groove perpendicular to the short side direction is rectangular.

3. A mattress according to claim 1 or 2, wherein the cross-sectional shape of the second groove perpendicular to the short side direction is a V-shape whose width continuously narrows from the lower surface to the upper surface.

4. A mattress according to claim 1 or 2, wherein the spacing between the first grooves is in the range of 10 mm to 50 mm.

5. A mattress according to claim 1 or 2, wherein the spacing between the second grooves is in the range of 5 mm to 20 mm.

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