JP2002276889A - Flat face structure, and manufacturing method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat face structure using double knitted fabric and useful as a cushion material, a manufacturing method and a device thereof. SOLUTION: This flat face structure 10 is composed of a double knitted fabric piece 11 formed by cutting the double knitted fabric along a prescribed outline and forming recessed grooves 18, 19 a little inner than the periphery thereof and a frame body 12 constituted by either of hard or soft synthetic resin, or a rubber, which is integrated-formed on a section 20 outer than recessed grooves 18, 19 of either of part or the whole of the periphery of the double knitted fabric piece. The flat face structure 10 is obtained by cutting the double knitted fabric along the prescribed outline, depressing the section a little inner than the periphery of the double knitted fabric piece 11 and forming the recessed grooves 18, 19, depressing the piece with a female mold and a male mold provided with protruding parts fitted into the recessed grooves 18, 19 and forming grooves for forming the frame body and injecting molten resin into the forming grooves for forming.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar structure, a method of manufacturing the same, and a manufacturing apparatus. More specifically, the present invention relates to a planar structure which can be suitably used as a cushion material or a surface material of furniture such as a chair or a bed, or a mat such as an entrance mat, and a method and an apparatus for producing the same.

[0002]

2. Description of the Related Art In general, a cushion such as a chair or a bed is constructed by filling a bag made of fabric with an elastic filler such as a panner or urethane foam and closing the bag. On the other hand, in recent years, both front and back knit fabrics,
A double knitted fabric comprising a connecting yarn for connecting the knitted fabric at intervals has been developed, and its use as a material for filling a cushion has been proposed (see Japanese Patent No. 2720985). Such a double knitted fabric can be preferably used as a filler because it has a suitable air permeability and elasticity, but when put in a bag, it has a suitable air permeability and other characteristics of the double knitted fabric. Certain high design properties and appropriate air permeability cannot be sufficiently exhibited.

[0003] In order to sufficiently exhibit the design properties and moderate air permeability, which are the advantages of the double knitted fabric, it is conceivable to use the double knitted fabric piece whose periphery has been cut without using a bag. However, since the double knitted fabric has a so-called three-dimensional braided structure, there is a problem that the yarn is frayed from the cut peripheral edge, and it is necessary to perform a terminal treatment of the cut surface. However, since the double knitted fabric itself is a new material, no effective terminal treatment method has been proposed yet.

For example, in the case of thick cloth such as quilting, it is possible to cover the cut surface with a biased ground or the like and to perform terminal treatment by sewing. However, in a double knit fabric in which the elasticity is increased by increasing the rigidity and density of the connecting thread, the needle of the sewing machine cannot be penetrated due to the high elasticity and high density of the connecting thread. The guide provided for feeding the fabric is caught, and it is extremely difficult to sew a biased area around.

On the other hand, Japanese Patent Application Laid-Open No. 2001-11983 discloses a terminal treatment method in which a groove is formed on both surfaces around a double knitted fabric, and a synthetic resin or aluminum rail is fitted into the groove. Propose to do. However, this method is suitable for constructing a stretched body by pulling the rail outward with a frame or the like, but when only the double knitted fabric piece is used as cushioning material, the double knitted fabric piece is used at the fitting portion. Is unsuitable because it comes off the rails. Further, it cannot be applied to a case where flexibility is required, such as a hammock.

An object of the present invention is to provide a sheet-like structure useful as a cushioning material by properly treating the terminal of the double knitted fabric. A further object of the present invention is to provide an efficient method and apparatus for manufacturing such a planar structure.

[0007]

A planar structure according to the present invention (claim 1) is a double knitted fabric comprising a double-layered knitted fabric and a connecting yarn for connecting the knitted fabric at intervals. A double knitted fabric piece cut into a predetermined contour and crushed somewhat inwardly from the periphery to make it a dense region, and a polymer integrally formed on a portion outside the dense region of the double knitted fabric piece And a frame made of a material. Examples of the polymer material include hard or soft synthetic resins, elastomers, rubbers, and the like. The frame body may be provided on the entire periphery of the double knitted fabric piece, or may be provided only on a part such as two opposing sides.
The planar structure of claim 1 includes a case where a frame is provided in such a part. The portion inside the frame outside the dense area may be squashed flat (claim 2).

[0008] The method for producing a planar structure of the present invention (Claim 3)
Cuts a double knitted fabric consisting of two layers of front and back knitted fabric and a connecting yarn that connects the knitted fabric at intervals, to a predetermined contour,
From the periphery of the obtained double knitted fabric piece, the inside is somewhat crushed flat to form a dense area, and further, the double knitted fabric piece is formed around the ridge and the double knitted fabric piece that presses the dense area. Pressing between a lower mold and an upper mold having a molding groove for forming a frame body,
The method is characterized in that a molten polymer material is injected into a cavity surrounded by the molding groove and molded. When the polymer material is a thermoplastic resin, it is preferable that the polymer material is injected and then cooled and cured. When the polymer material is rubber or thermosetting resin, it is not necessary to forcibly cool the polymer. In any of the above manufacturing methods, when the double knitted fabric piece is sandwiched between the upper mold and the lower mold, the dense region may be simultaneously formed (claim 5).

[0009] The apparatus for manufacturing a planar structure according to the present invention (claim 6) comprises a ridge for pressing at least one of the lower mold and the upper mold from the periphery of the double knitted fabric piece to the inside thereof, A lower die and an upper die having a forming groove for forming a frame around the double knitted fabric piece; a device for clamping the lower die and the upper die; and a device for injecting a molten material into the forming groove. It is characterized by having. The lower mold and the upper mold are preferably provided with a heating device for heating to a predetermined temperature. Depending on the polymer material, it is preferable to provide a cooling device for curing and molding the molten material. Further, in this manufacturing apparatus, it is preferable that the apparatus for clamping the lower mold and the upper mold and the apparatus for injecting the molten material are simultaneously operated (claim 7).

[0010]

In the planar structure of the present invention (claim 1), a frame made of a polymer material such as synthetic resin or rubber is integrally formed around the double knitted fabric piece. Therefore, there is no problem that the yarn is frayed from the surrounding cut end surface during use. Therefore, it can be used as it is as a cushion material or a mat material without being filled in a bag or the like. And the cushion effect and the design effect of the surface of the double knitted fabric can be sufficiently exhibited. Further, since the polymer material is impregnated in the gap between the yarns at the periphery of the double knitted fabric piece, the frame and the double knitted fabric piece are firmly integrated, and the frame body is It does not come off or come off. Furthermore, since a dense area is formed somewhat inward from the periphery of the double knitted fabric piece,
When forming the frame, the polymeric material does not penetrate beyond the dense area to the inside of the double knitted fabric piece. Therefore, the design is high. In addition, the color of the front and back of the double knitted fabric piece can be changed,
Further, the frame can be any color. In the case where the portion inside the frame outside the dense region is a flat structure crushed flat (claim 2), the end of the double knitted fabric piece is exposed outside the frame. Less likely to occur.

[0011] The manufacturing method of the planar structure of the present invention (Claim 3)
Is to crush the inside of the double knitted fabric somewhat flat to form a dense area, and form the surrounding frame while pressing the dense area with the ridges of the upper and lower molds. The molten polymer material does not penetrate to the inside of the ground piece, and is integrally formed with the peripheral portion of the double knitted fabric piece included therein. Therefore, a planar structure having a high design property can be manufactured. The manufacturing method (claim 4) in which the dense region is simultaneously formed when the double knitted fabric piece is pressed by the upper and lower molds is easy to implement because the number of manufacturing steps is reduced.

The manufacturing apparatus of the present invention (claim 5) can efficiently carry out the above manufacturing method. In a manufacturing apparatus in which a heating device is provided in a mold, a sufficiently molten polymer material flows into a cavity formed by molding grooves of upper and lower molds.
Therefore, a strong frame can be formed. In such a manufacturing apparatus, in the manufacturing apparatus configured to simultaneously operate the apparatus for clamping the lower mold and the upper mold and the apparatus for injecting the molten material (claim 6), the cycle time required for the manufacturing is shortened, and the efficiency is reduced. It can be manufactured in a special way.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a planar structure according to the present invention. 1 is a perspective view showing an embodiment of the planar structure of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is an embodiment of the apparatus for producing a planar structure of the present invention. Perspective view,
4 is a cross-sectional view taken along the line IV-IV of FIG. 3, FIG. 5 is a cross-sectional view showing a further embodiment of the manufacturing apparatus of the present invention together with a planar structure, and FIG. FIG. 7 is a perspective view showing an embodiment, FIG. 7 is a process chart showing one embodiment of a method for manufacturing a planar structure of the present invention, and FIG. 8 is a view showing another embodiment of a method for manufacturing a planar structure of the present invention. 9a and 9b.
10 is a main part process diagram showing another embodiment of the manufacturing method of the planar structure of the present invention, FIG. 10 is a perspective view showing another embodiment of the planar structure of the present invention, and FIG. 1 is a perspective view showing a mold for manufacturing a planar structure, FIG. 12 is a perspective view showing an example of a pipe chair using the planar structure of the present invention, and FIG.
FIG. 3 is a perspective view showing an example of a hammock using the planar structure of the present invention.

A planar structure 10 shown in FIG. 1 includes a double knitted fabric piece 11 obtained by cutting a double knitted fabric into a rectangular shape, and the double knitted fabric piece 1.
1 and a frame 12 made of a polymer material and integrally formed around the periphery. The double knitted fabric is conventionally known, and will be described based on an enlarged double knitted fabric piece 11 shown in FIG.
It is a so-called three-dimensional net-shaped knitted fabric composed of connecting yarns 17 that connect 5, 16 at an interval. As shown in FIG. 2, some inside from the periphery of the double knitted fabric piece 11,
V-shaped concave grooves 18 and 19 crushed from both front and back surfaces are formed, and a frame 12 made of a polymer material having a U-shaped cross section is joined to an outer portion 20 thereof.

Since the double knitted fabric piece 11 has a space between the yarns, a part of the polymer material constituting the frame 12 penetrates into the inside of the double knitted fabric piece 11 at the outer portion 20 thereof. And has an anchor effect. Therefore, the frame 12 and the double knitted fabric piece 11 are firmly joined. Upper and lower grooves 18,
The portion 26 between the 19 forms a dense area where the knitted fabric is dense. The polymer material does not penetrate inside the thin portion 26, that is, on the center side of the planar structure 10. In this embodiment, the grooves 18 and 19 are vertically arranged.
However, as in the case of the planar structure 27 in FIG. 5, a deep concave groove 18 may be formed on one side and the other side may be flattened. That is, if the distance T between the concave grooves 18 and 19 is smaller than a certain value, the thin portion 26 may be located at any position in the thickness direction, and one side may be omitted. Since the cut ends of the fibers around the double knitted fabric piece 11 are fixed by the polymer material of the frame 12, such a planar structure 10 does not fray. Further, it has sufficient strength for ordinary uses such as cushioning materials and mats. Further, by mixing fibers such as glass fibers and carbon fibers or reinforcing materials such as powder into the frame 11, the strength can be further improved.

The double-layered fabric piece 11 has two layers of front and back knitted fabrics 15, 1
As a material of 6 and the connecting yarn 17, thermoplastic resin fibers such as polyester, acrylic, polyamide (nylon), polyimide, polypropylene, and polyethylene are preferably used. Natural fibers such as cotton and wool may be used for the two-layered knitted fabrics 15 and 16.

The frame 12 is made of a hard resin such as hard polyvinyl chloride (PVC) or polystyrene (P).
Thermoplastic resins such as S), ABS, AES, polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT) are used.
Further, a thermosetting resin such as an acrylic resin or a phenol resin can also be used as the material of the hard frame 12.
As the soft resin, soft polyvinyl chloride (PVC)
Also, various elastomers such as styrene, polyester, urethane and polyolefin, ethylene-vinyl ester copolymer, ethylene-acrylate copolymer and the like are used. Other polymer materials include natural rubber (NR), nitrile rubber (NBR), styrene-butadiene rubber (SBR), chloroprene rubber (CR),
Rubbers such as ethylene-propylene rubber (EPDM) can also be used. Regarding the material of the frame 12, regardless of whether it is hard or soft, a foam of the above material may be employed.

The fiber and the frame of the double knitted fabric have a melting point (mold temperature at the time of molding) of the resin of the frame higher than the glass transition point of the fiber when the respective materials are thermoplastic. A combination having a higher fiber melting point is preferred. Thus, when the frame is integrally formed around the double knitted fabric piece, the frame can be formed without giving the double knitted fabric an adverse effect such as pulling due to melting. In addition, if the frame is made of polyester and the double knitted fabric piece is made of polyester fiber, the integration can be performed more firmly. In addition, there is no need to separate and discard at the time of disposal, and recycling is easy. Double knitted fabric piece 11
And the color of the frame 12 can be arbitrarily selected. Thereby, the planar structure 10 having high designability is obtained.

FIG. 3 shows a basic structure of a mold set including a lower mold 21 and an upper mold 22 for manufacturing the above-mentioned planar structure 10. The lower mold 21 is made of a rectangular plate material manufactured from a steel material for a mold, and as shown in FIG. The cavity 23 is formed in a rectangular shape. Inside the forming groove 23, a ridge 24 for forming a concave groove (reference numerals 18 and 19 in FIG. 2) of the double knitted fabric piece is formed so as to have a frame shape in plan view. . This ridge 24
Is the inner surface of the molding groove 22. Inside the ridge 24, a cavity 25 for receiving a double knitted fabric piece is formed.
The upper mold 22 has substantially the same configuration as that of the lower mold 21, and FIG.
As shown in FIG.

The position in the thickness direction of the thin portion formed by the concave grooves 18 and 19 is determined by the use of the planar structure. For example, in the case of a cushion material having no front and back surfaces, it is desirable that the cushion material is located at the center of the thickness of the cloth, as in a thin portion indicated by reference numeral 26 in FIG. However, when it is fixed by use of only one side with a cushion material of a chair or the like, it may be better to flatten the surface opposite to the side to be used, which is easier to fix. FIG. 5 shows the basic structure of the planar structure 27 which is flat without forming a concave groove on one surface (the lower surface in this case) of the double knitted fabric piece 11 and a mold set for manufacturing the same. . In this mold set, the upper mold 22 is formed with the ridge 24, but the lower mold 21 is not formed with the ridge, and is substantially flat. And the protrusion 24 of the upper mold 22 when closed
The protrusions 24 of the upper mold 22 are higher so that the distance T between the gap and the lower mold 21 is the same as that of the mold set shown in FIG.

In this mold set, the lower mold 21 is flat without a central cavity in which the double knitted fabric piece 11 enters. This is because if a cavity is provided in the lower mold 21, a concave groove or a step is formed at a position corresponding to the elasticity of the fabric when the double knitted fabric piece is pressed, and the protrusion of the lower mold is omitted. This is because the bottom surface is not flattened despite the fact that it is in the above condition. That is, by omitting the ridges and cavities from the lower mold, when pressing the double knitted fabric piece, the lower surface of the double knitted fabric piece is supported in contact with the lower mold, and the height of the double knitted fabric piece is reduced. Will be controlled. Thus, the groove and the frame can be formed while the lower surface of the double knitted fabric piece is kept flat. When the protrusion of the upper mold 22 is omitted, a cavity may be provided, but it is preferable to omit the cavity in order to secure a desired shape. By using this method, the double knitted fabric piece 1
The position in the height direction of the thin portion 26 separating the peripheral portion 20 and the central portion can be controlled to a desired position, and the step shape or the like can be made a desired shape. If no cavity is provided at the center, the double knitted fabric piece may be affected by heat due to contact with the mold. If such influence is not desired, a cavity 25 is formed in a mold to which the double knitted fabric piece 11 contacts as shown by an imaginary line, and a heat insulating material 25a is placed in the cavity 25. Thereby, the influence of heat can be reduced.

In the mold set of FIG. 5, the molding groove 23a of the lower mold 21 is made shallow. Further, the forming groove 2 of the upper die 22
3b has a triangular cross section. Thereby, as shown in the lower part, a frame body having a rounded triangular cross section whose lower surface is somewhat lower than the bottom of the double knitted fabric piece 11 and whose upper end is almost the same height as the upper surface of the double knitted fabric piece 11. 12 can be formed.

The above dies 21 and 22 show only the basic structure, and when used in press molding, the upper dies 22 are used.
And a mechanism necessary for press forming such as a cooling pipe and a heating device is added to each of the upper mold 22 and the lower mold 21. In the case of injection molding, a mechanism required for injection molding, such as a gate and an ejector pin, is added.

The molds shown in FIGS. 4 and 5 are used to integrally mold the frame around the entire double knitted fabric piece at one time.
Are used when a frame is formed on one side of the double knitted fabric piece. The configuration of the dies 31, 32 is shown in FIG.
Are substantially the same as the corresponding portions of the molds 21 and 22 shown in FIG. This can be used in a small press with a small pressing force or a small injection molding machine with a small clamping pressure. When the dies 31 and 32 are used, the frame can be sequentially provided on the four sides of the double knitted fabric piece. Moreover, it can be used when a frame is provided only on the first to third sides of the double knitted fabric piece.

FIG. 7 shows the steps in the case where press molding is used for the resin molding for the terminal treatment of the double knitted fabric piece. First, the sheet-shaped double knitted fabric 40 is cut into a predetermined contour to obtain a double knitted fabric piece 41 (cutting step S1). For this cutting, for example, a press machine in which a cutting die is set or a cutter having a rotary blade is used. The cut dimensions are somewhat smaller than the dimensions to be finished as a planar structure,
The dimensions are larger than the ridges 24 so that the outer peripheral portion is left outside the ridges 24 of the molding dies 21 and 22. The cutting can be performed on four sides simultaneously or one side at a time. Further, at the time of cutting, a groove (reference numerals 18 and 19 in FIG. 2) can be formed around the double knitted fabric piece, or the groove can be formed alone before forming the frame. However, in the present embodiment, the pressing is performed simultaneously in a pressing step S3 described later.

Next, the mold is heated by a heating device such as an electric heater 44 provided in the molds 21 and 22. About 17 if the double knitted fabric piece is made only of polyester fiber
0 ° C. If the double knitted fabric piece is made of another fiber, the temperature is set according to the fiber. When the double knitted fabric piece is made of synthetic resin yarn, the temperature setting of the mold is set at a temperature lower than the melting temperature of the synthetic resin constituting the double knitted fabric piece and higher than the glass transition point. It is preferred that However, before the frame 12 is formed, the groove 1 alone is formed.
In the case of molding 8, 19, even if the temperature is lower than the above-mentioned set temperature, molding can be easily performed by rapidly cooling after molding. However, it is necessary to change the temperature setting depending on the fiber used.

Next, the double knitted fabric piece 41 obtained by cutting as described above is set at a predetermined position of the lower mold 21 (setting step S2).

Next, the upper mold 22 is lowered by the press machine, and the double knitted fabric piece 41 on the lower mold 21 is pressed.
At this time, the ridge 2 of the heated upper mold 22 and lower mold 21
Since the grooves 4 and 24 pinch a predetermined portion of the double knitted fabric piece 41, the concave grooves 18 and 19 are formed at those positions (the concave groove forming step S3).

Further, the molding groove 23 is kept pressed.
The molten resin is poured into the resin (resin pouring step S4).
The melted resin is impregnated around the double knitted fabric piece 41 and is shaped according to the shape of the forming groove 23. At this time, the dies 21, 2
Since the double knitted fabric piece 41 is still being bitten by the second ridges 24, 24, the molten resin does not seep out to the center of the double knitted fabric piece 41.

By cooling the molten resin in this pressed state until it hardens, the soft or hard resin material is mixed with the double knitted fabric piece over a part or the whole of the peripheral portion of the double knitted fabric piece 41. It can be molded integrally. Thus, a planar structure 10 as shown in FIG. 1 can be obtained.

In the above embodiment, as in the resin pouring step S4 of FIG. 7, the portion 20 outside the region (dense region) 26 thinned by the concave grooves 18 and 19 has almost the original thickness. . However, the frame 1 is made of a high-viscosity material such as rubber.
When forming 2, the outer part 20 is pressed into the thin rice crack as shown in FIG. 8 under the pressure of the material to be filled. Even in such a flattened state, unlike the dense area 26, the fiber is impregnated with the molten material and penetrates the space between the fibers to be integrated with the surrounding material. for that reason,
The frame 12 is firmly fixed to the double knitted fabric piece 11 by the anchor action.

When the double knitted fabric piece 11 is set in the molds 21 and 22 as in the setting step S3 in FIG. 7, the double knitted fabric piece 11 is pressed by the ridges 24 and crushed thinly. However, due to the influence, a part of the connecting yarn 17 at the end may come off from the molding groove 23 and be sandwiched between the molds 21 and 22 as shown in FIG. 9A or may come into contact with the inner surface of the molding groove 23. . That is, the end of the connecting yarn 17 is knitted on one side of the upper and lower knitted fabrics, but is free from the other side, so that such jumping out may occur regardless of the viscosity level. is there. Then, when the frame is formed as it is, the end portion of the free connecting yarn 17a has a shape protruding from the surface of the frame. In that case, not only the appearance becomes poor, but also the user feels tingling, which is not preferable.

In order to prevent the free connecting yarn 17a from jumping out, as shown in FIG. 9b, before inserting the double knitted fabric piece 11 into the mold, the peripheral portion of the double knitted fabric piece 11, in particular, the ridge 24 from the peripheral edge. It is preferable to crush the area leading to the dense region 26 to be crushed from the beginning. When crushed in such a manner, the free connecting yarn 17a is held down, and there is little possibility that the double knitted fabric piece jumps out when the double knitted fabric piece is pressed with the ridge 24.
In addition, you may crush only the peripheral part, without crushing the whole area crushed by the ridge 24 from the peripheral part.

In the above embodiment, the planar planar structure 10
However, as shown in FIG. 10, for example, the planar structure of the present invention can be formed in a three-dimensional shape with a curved surface. The frame 12 of the planar structure 50 is a combination of a pair of straight frame portions 12a and a pair of curved frame portions 12b. The double knitted fabric piece 11 is stretched in the curved frame body 12 to form a curved surface. In the case of manufacturing such a planar structure 50, the structures of the dies 51 and 52 are three-dimensionally configured as shown in FIG. 11, and the resin forming the frame 12 is a hard resin. Thereby, as the hard resin and the double knitted fabric piece 11 are integrated, it is possible to form a three-dimensional planar structure 50 as shown in FIG. Also, as shown in FIG. 5, if a method of controlling the position in the height direction of the portion 26 thinned by the concave groove 18 is used, for example, a lower mold adapted to the shape of the seat or back of the chair may be manufactured. The planar structure can be shaped into a shape along the seat or back.

FIG. 12 is a perspective view of a pipe chair 53 used in a conference room or the like in which a curved planar structure 50 is used as a back portion (backrest). In this example, a fitting portion 55 for fitting with a pipe frame 54 of a pipe chair is integrally formed with the frame 12. Such a fitting portion 55 can be formed simultaneously by providing cavities corresponding to the fitting portion 55 in dies 51 and 52 for forming the frame body 12. By forming the fitting portion 55 integrally with the frame 12 in this manner, the fitting portion 55 is
4, the pipe chair 53 can be easily manufactured.

In a usual case, a cushioning filler such as urethane foam is covered with a sheet or filled in a bag to produce a cushion, and the cushion is further applied to a plate-like base as a strength member. Fixed,
Further, a manufacturing process of fixing it to a pipe frame is required. However, in the pipe chair 53 of FIG. 11, the manufacturing process is significantly shortened. Further, if the double knitted fabric piece 11 is made of only polyester fiber and the frame 12 is made of only polyester resin, it is only necessary to separate the backrest from the metal pipe frame 54 when discarding the pipe chair. The backrest itself does not need to be discarded separately. Therefore, recycling is easy. In addition,
The planar structure of the present invention can be adopted not only for the backrest but also for the seat 56.

FIG. 13 is a perspective view showing a case where the planar structure of the present invention is applied to a hammock. This hammock 6
In order to manufacture the nonwoven fabric 0, first, flexible synthetic resin frames 62, 62 are integrally formed on the left and right ends of a strip-shaped double knitted fabric piece 61 having a predetermined width, for example, a width of about 1 m. Keep it. And it cut | disconnects about 2 m in a longitudinal direction, and the frame 63 is shape | molded by hard synthetic resin at those cut ends. At this time, several holes 65 for passing the rope 64 are provided. Then, the ropes 64 passed through the holes 65 may be bundled for each frame 62 and suspended in the same manner as a conventional hammock. Thereby, a new hammock having a cushioning property in the fabric portion can be realized.

In the above embodiment, the cross-sectional shape of the frame 12 is rectangular, but may be other shapes such as a circle.

In the embodiment of the manufacturing method shown in FIG. 7 and the like, in the concave groove forming step S3, the double knitted fabric piece 41 is sandwiched between the ridges 24 of the molds 21 and 22, and crushed thinly.
In step 4, the molten resin is prevented from flowing to the inside.
However, when the double knitted fabric piece is coarse, even if the grooves 24 are formed, the thin portions 26 between the upper limit grooves 24 are not completely filled with the crushed cloth, and the molten resin flows inside. There are cases. When the double knitted fabric piece has a coarse mesh as described above, it is preferable to perform a sealing process on a thin portion before pouring the resin. As the filling process, for example, when the concave groove 24 is formed, an adhesive, a thermosetting resin, or a thermoplastic resin having a melting point higher than that of the resin used for the frame body is formed in a double form with the ridge 24 of the mold. It is sandwiched between the knitted fabric pieces 41, and is melted by the raised ridges 24. Alternatively, such a resin or an adhesive is applied in advance to a portion where a concave groove is to be formed. By doing so, the thin portion 26 formed by the concave groove is impregnated with the adhesive or the resin, so that a so-called sealing effect is exerted. Therefore, even with a double knitted fabric piece having a coarse mesh, the frame can be formed on the terminal without any problem. It is to be noted that the above-described sealing process may be performed after the concave groove is once formed by press working or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a planar structure of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing an embodiment of the apparatus for manufacturing a planar structure according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a cross-sectional view showing another embodiment of the manufacturing apparatus of the present invention together with the obtained planar molded body.

FIG. 6 is a perspective view showing another embodiment of the manufacturing apparatus of the present invention.

FIG. 7 is a process chart showing one embodiment of a method for manufacturing a planar structure of the present invention.

FIG. 8 is a main part process view showing another embodiment of the method for producing a planar structure of the present invention.

FIGS. 9A and 9B are main part process charts showing still another embodiment of the method for manufacturing a planar structure according to the present invention.

FIG. 10 is a perspective view showing another embodiment of the planar structure of the present invention.

FIG. 11 is a perspective view showing a mold for manufacturing the planar structure of FIG. 10;

FIG. 12 is a perspective view showing an example of a pipe chair using the planar structure of the present invention.

FIG. 13 is a perspective view showing an example of a hammock using the planar structure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Planar structure 11 Double knitted fabric piece 12 Frame body 15, 16 Knitted fabric 17 Connecting thread 17a Free connecting thread 18, 19 Concave groove 20 Outer part 21 Lower mold 22 Upper mold 23 Molding groove 24 Ridge 25 Cavity 26 Thin part 27 Planar structure 28 Double knitted fabric piece 25a Heat insulating material 23a, 23b Molding groove 31, 32 Mold 41 Double knitted fabric piece S1 Cutting process 44 Electric heater 50 Planar structure 51, 52 Mold 53 Pipe chair 54 Pipe frame 55 Fitting part 56 Seat part 60 Hammock 61 Double knitted fabric piece 62 Frame 63 Frame 64 Rope 65 hole

Claims (7)

[Claims] 1. A double knitted fabric comprising a double-layered knitted fabric and a connecting yarn for connecting the knitted fabric at an interval, is cut into a predetermined contour, and is pressed somewhat flat inside from the periphery. A planar structure comprising a double knitted fabric piece crushed into a dense region and a frame made of a polymer material integrally formed on a portion of the double knitted fabric piece outside the dense region. 2. The planar structure according to claim 1, wherein a portion inside the frame outside the dense region is squashed flat. 3. A double knitted fabric comprising a double-layered knitted fabric comprising front and back two-layered knitted fabric and a connecting yarn for connecting the knitted fabric at an interval, is cut into a predetermined contour. The dense area is formed by pressing the inside somewhat from the surroundings, and the double knitted fabric piece is further formed with a ridge for pressing the dense area, and a forming groove for forming a frame around the double knitted fabric piece. A method for producing a planar structure, wherein the planar polymer is sandwiched between a lower mold and an upper mold, and a molten polymer material is injected into a cavity surrounded by the molding groove and molded. 4. The method for manufacturing a planar structure according to claim 3, wherein the polymer material is injected and then cooled and cured. 5. The dense region is formed simultaneously when the double knitted fabric piece is pressed between the upper die and the lower die.
Production method as described. 6. A ridge on at least one of an upper mold and a lower mold for pinching the inside of the double knitted fabric piece to some extent from the periphery thereof, and a ridge for forming a frame around the double knitted fabric piece. An apparatus for manufacturing a planar structure, comprising: an upper die and a lower die having a forming groove; a device for pressing the upper die and the lower die; and a device for injecting a molten material into the forming groove. 7. The manufacturing apparatus according to claim 6, wherein the apparatus for clamping the upper mold and the lower mold and the apparatus for injecting the molten material are simultaneously operated.