JPH10179326A - Structure of seat or seat back of a chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a shell member of a chair having an undercut as a connecting structure without using a mold having a complex split structure. SOLUTION: This structure comprises an inner shell 2 as a core material of a structure for a seat and a seat back of a chair and an outer shell 3 as a backing cover for covering the back side of the inner shell 2 which are directly melt-adhered through a melt adhering sheet 5 which generates heat by an electromagnetic induction heating. As desired, a fixing member 4 engaged to a fixing through hole 3a formed on another shell 3 to the shell 2 or the first fixing member constructing a couple of fixing members of a male and female one and the second fixing member with each of the shells are connected by melt adhering through the melt adhering sheet heated by an electromagnetic induction heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure such as a chair seat and a backrest. More specifically, the present invention relates to an improvement in the structure of a joint having an undercut that connects an inner shell that is a core material of a chair structure and an outer shell that is a back cover.

[0002]

2. Description of the Related Art Structures such as a seat portion and a backrest of a chair include a core material called an inner shell, a cushion made of urethane foam or the like supported by the core material, and a vinyl stretched on the core material without slack. And an upholstery such as leather and cloth. And, for the upper-covered fabric, turn the edge part to the back side of the core material and gently pull it to extend the slack on the front side, and then use a fastening needle such as a tack or a U-shaped needle (stapling needle) in that state It is fixed directly to the core material by welding or welding, or it is covered by squeezing the edge using a tightening means such as a wire or a rubber string. Here, a back cover called an outer shell is attached to the back side of the core material in order to hide the frayed or cut surface of the edge of the upper covering material and improve the aesthetic appearance.

In many cases, the core material and the back cover are formed by injection-molded plastic molded products. Then, as shown in FIG.
Are fixed to each other by a locking hole 103 formed integrally at several places on the back surface of the core material 101 and a locking claw 104 formed at a position corresponding to the locking hole 103 inside the back cover 102. That is, the core member 101 has a cylindrical portion 1 protruding from the back surface thereof.
01a is formed, and an inner periphery of an edge 101b formed inside the front end of the cylindrical portion 101a is a locking hole 103.
Also, a return portion 104a of the locking claw 104 is attached to the edge 101b.
Is locked, the locking hole 103 and the locking claw 104 are locked.

[0004]

However, in the chair structure described above, since the so-called undercut / return portion 104a is formed on the locking claw 104, the structure of the injection mold is complicated. Therefore, there is a problem that the mold cost and, consequently, the production cost are increased. That is, the presence of the return portion 104a allows the back cover 102
Since the mold cannot be opened in the thickness direction of the mold, it is necessary to break the mold in a direction not to be caught by the return portion 104a. As a result, the mold structure becomes complicated, which complicates the molding operation of the shell member and increases the molding cost.

Accordingly, the present invention provides a structure such as a chair seat or a backrest which enables a shell member having a locking claw with an undercut to be formed without using a mold having a complicated split structure. The purpose is to:

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention according to claim 1 is directed to a structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back side of the inner shell. In the object, a locking hole formed in one of the inner shell and the outer shell, a locking member engaging with the locking hole,
A welding sheet interposed between the other shell and the locking member and capable of generating heat by electromagnetic induction, wherein the locking member and one shell are welded by the heat generated from the welding sheet and engage with the locking member. The engagement member and the other shell are connected by engagement with the hole.

Therefore, since the locking member and the shell to which the locking member is attached are separate bodies, the portion engaging with the locking hole does not become an undercut in molding. Further, the locking hole formed in the other shell can also be formed into a shape having no undercut. For this reason, when molding each shell,
It can be molded without considering undercut. Accordingly, when the shell is injection-molded, the mold structure can be simplified, and when the mold is opened, the shell may be pulled out in one direction, so that the molding operation is also facilitated. In addition, since it is not necessary to split the mold in a plurality of directions, the shape of the mold is simplified. In addition, the shell can be formed by, for example, press working in which an undercut cannot be formed. Furthermore, since the locking member and the shell are welded by electromagnetic induction heating, even if the locking member and the shell are formed of a material that is difficult to adhere with an adhesive, the locking member and the shell are fixed with sufficient strength. You.

According to a second aspect of the present invention, there is provided a structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back surface of the inner shell.
A first locking member having a locking hole, a second locking member to be engaged with the first locking member, and a first locking between one of an inner shell and an outer shell A welding sheet interposed between the member and the other shell and the second locking member and capable of generating heat by electromagnetic induction, wherein the first and second locking members and the shells are respectively formed of the welding sheet. The first locking member and the second locking member are connected by being welded by heat generation and engaging the second locking member with the engagement hole of the first locking member.

[0009] In this case, as in the first aspect,
Since the second locking member that connects the inner shell and the outer shell can be formed separately from any of the shells, the portion that engages with the locking hole of the first locking member does not become a molded undercut. Therefore, the same effect as the first aspect of the invention can be obtained. In addition, since the positions at which the first and second locking members are attached to the shells can be arbitrarily set, the degree of freedom of the connecting position between the shells increases, and the number of connecting points can be easily increased or decreased.

Further, according to the present invention, in a structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back side of the inner shell, the inner shell and the outer shell are in direct contact with each other. And a welding sheet interposed between both shells of the contact portion and capable of generating heat by electromagnetic induction, and the inner shell and the outer shell are directly welded by the heat generated by the welding sheet. Like that.

In this case, since the inner shell and the outer shell are directly welded to each other without using a locking member, it is not necessary to form an undercut shape in any of the shells, and the same operation as in claims 1 and 2 can be obtained. In addition, the number of parts can be further reduced. In addition, the portions where the shells come into contact with each other are formed in a relatively large size, and the position for attaching the welding sheet can be arbitrarily selected from among them. Is done. Also, by reducing the number of parts,
The manufacturing operation can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings. 1 to 3 show an embodiment in which the chair structure of the present invention is applied to a seat 1. FIG. The seat 1 of the chair includes an inner shell 2 functioning as a core material, and an outer shell 3 functioning as a back cover that covers the back surface of the inner shell 2. A locking member 4 having a locking claw 4c is welded to a back surface of one shell, for example, the inner shell 2 by a welding sheet 5. A locking hole 3a is formed on the outer shell 3 side, which is the other shell.
When the locking hole 3a is locked to the locking member 4,
The inner shell 2 and the outer shell 3 are connected and integrated.

The inner shell 2 is made of, for example, a sheet material made of polypropylene. On the front side of the inner shell 2, a cushion 6 made of a foamed resin such as urethane foam and an upholstery material 7 made of vinyl covering the cushion 6 and the inner shell 2 are integrated by press working. That is, by forming the inner shell 2, the cushion 6, and the upholstery 7, which are sheet materials, on top of each other and press-working them, their formation and integration are simultaneously performed. The peripheral portion 7a of the upper covering 7 is directly fixed to the peripheral portion 2a of the inner shell 2 at the time of press working.

Further, in the present embodiment, the inner shell 2
Is made of polypropylene, but is not limited to pure polypropylene, and may be a mixture of other materials with polypropylene as a main material. Other materials to be mixed include, for example, recycled materials, fiberglass,
Talc, wood flour, reinforcing materials, etc. Thereby, the rigidity of the inner shell 2 can be increased. Further, the polypropylene material includes a recycled polypropylene material as a recycled product.

In the present embodiment, vinyl is used as the upholstery 7. However, the present invention is not limited to this, and polypropylene, leather, artificial leather, or cloth may be used. Further, in the present embodiment, the cushion 6 and the upholstery 7 are integrally attached to the inner shell 2 by press working. However, the present invention is not limited to this. 7 to the inner shell 2
May be fixed directly to the inner shell 2 by fastening or welding a stud, or may be attached by narrowing the edge using a tightening means such as a wire or a rubber string.

A part of the outer shell 3 attached to the back side of the inner shell 2 is formed with a protruding part 3 b protruding inwardly of the seat part 1. A locking hole 3a is formed in the distal end surface of the protruding portion 3b. A guide surface 3c formed of a slope is formed at the edge of the locking hole 3a so that the locking claw 4c of the locking member 4 can be easily inserted from the inside of the outer shell 3.

A locking member 4 is attached to the back surface of the inner shell 2 at a position facing the locking hole 3a of the outer shell 3 with a welding sheet 5 interposed therebetween. Locking member 4
Is composed of a plate-shaped substrate portion 4a, a pin portion 4b protruding from the substrate to one side, and a locking claw 4c formed of a return portion formed at the tip of the pin portion 4b. The board portion 4a, the pin portion 4b, and the locking claw 4c are integrally formed by injection molding of polypropylene.

The welding sheet 5 is a sheet capable of generating heat by electromagnetic induction heating, and is made of, for example, a sheet material containing iron powder mainly composed of polypropylene (for example, Rio Hard, manufactured by Toyo Ink Mfg. Co., Ltd.). Therefore, when the welding sheet 5 is sandwiched between the substrate portion 4 a of the locking member 4 and the back surface of the inner shell 2, and high-frequency electromagnetic waves are irradiated in this state, electromagnetic induction heating occurs in the iron powder of the welding sheet 5. The welding sheet 5 and the portion of the locking member 4 that comes into contact with the welding sheet 5 and the inner shell 2 are melted and welded. In the present embodiment, the metal material contained in the welding sheet 5 is iron powder, but is not limited thereto, and the metal material contained in the welding sheet 5 may be iron filaments or wires. The material of the metal material may be other than iron as long as it is a metal that can be heated by electromagnetic induction. Further, the resin serving as the base of the welding sheet 5 is preferably a material compatible with the shell material and the locking member.

In the present embodiment, since the inner shell 2, the locking member 4, and the welding sheet 5 are all made of polypropylene, the welding is performed by melting the contact portions of the respective members. However, the inner shell 2, the locking member 4, and the welding sheet 5 need only be resins compatible with each other, and need not be made of the same material. Therefore, for example, the inner shell 2 and the locking member 4 may be made of polypropylene which is suitable as a structural material of a chair, while the welding sheet 5 may be made of polyethylene which is compatible with them. Further, for example, the inner shell 2 and the locking member 4 are A
The welding sheet 5 may be made of polycarbonate and made of polycarbonate. Also in these cases, the fused portions of the welding sheet 5 and the inner shell 2 and the locking member 4 are mixed, so that the welding of the inner shell 2 and the locking member 4 can be performed.

Further, as the welding sheet 5, it is most preferable to use a sheet material mainly composed of polypropylene containing iron powder or the like as in the present embodiment. However, the present invention is not limited to this. A single metal of a possible material, for example, a metal plate may be used. In this case, it is preferable that the metal plate be smaller than the area of the welded portion between the inner shell 2 and the board portion 4a of the locking member 4, and be disposed substantially at the center of the welded portion. As a result, the locking member 4 and the inner shell 2 that are melted around the heated metal plate are directly welded to each other.

The welding sheet 5 may be a metal wire or a metal mesh that does not use a resin material, in addition to the above-described metal plate. In this case, the locking member 4 and the inner shell 2 around the metal wire or the metal fiber of the metal mesh.
Are melted and directly welded while sandwiching a metal wire or a metal mesh. Therefore, welding can be performed on the entire surface of the welded portion between the locking member 4 and the inner shell 2, so that the strength after welding can be improved.

When the seat 1 having the above-described structure is manufactured, a sheet-like inner shell 2, a cushion 6, and an upper fabric 7 are prepared. Then, these are stacked and formed by press working, and are simultaneously integrated. The welding sheet 5 and the locking member 4 are placed on the back surface of the inner shell 2 at positions facing the locking holes 3a of the outer shell 3, and are irradiated with high-frequency electromagnetic waves. Thereby, the welding sheet 5 and the inner shell 2 and the locking member 4 that come into contact with the welding sheet 5 are melted and welded. On the other hand, the outer shell 3 is integrally formed by injection molding of polypropylene or the like.

Then, the outer shell 3 is attached to the inner shell 2 by engaging and locking the locking holes 3a of the outer shell 3 with the locking claws 4c of the locking member 4. At this time, since the locking claw 4c is hooked on the edge of the locking hole 3a, the outer shell 3 does not easily come off.

Therefore, according to the present embodiment, the seat 1
The inner shell 2, the cushion 6, and the upholstery 7 can be integrally formed by press working, so that the inner shell 2 can be formed and the cushion 6 and the upholstery 7 can be easily attached. Therefore, the manufacturing operation of the seat 1 can be speeded up, and the manufacturing cost of the seat 1 can be reduced.

Also, since the inner shell 2 and the locking member 4 are made of polypropylene, the inner shell 2 and the locking member 4 having sufficient rigidity can be obtained at low cost. Moreover, it is difficult to firmly bond the members made of polypropylene with an adhesive, but in the present embodiment, the members are welded by electromagnetic induction heating with the welding sheet interposed therebetween, so that a strong attachment can be easily performed. it can.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the locking member 4 is attached to the inner shell 2 and the locking hole 3a is formed in the outer shell 3. However, the present invention is not limited to this, and the locking hole is formed in the inner shell 2 and the outer shell 3 is formed. Alternatively, the locking member 4 may be attached with the welding sheet 5. In this case, it is needless to say that the welding sheet 5, the outer shell 3, and the locking member 4 are made of mutually compatible resins.

In the embodiment shown in FIG. 1, the locking hole 3a is formed integrally with the outer shell 3. However, the present invention is not limited to this, and the locking hole is formed in a member separate from the shell so that the shell can be attached to the shell. You may do it. For example, as shown in FIG. 4, the first locking member 8 provided with the locking hole 3 may be attached to the outer shell 3. The first locking member 8 has a box shape, and includes a board portion 8a, a top plate portion 8b facing the board portion 8a, and a locking hole 8c formed in the center of the top plate portion 8b. In this embodiment, the locking hole 8c is cut out to the side and opened to the side. However, the present invention is not limited to this, and the locking hole 8c may have a circular shape without a notch. The material of the first locking member 8 is a material as a second locking member having the locking claw 4 and forming a pair of male and female locking means with the first locking member 8 described above. The inner shell 2 is made of the same material as the stopper member (hereinafter, simply referred to as a retaining member) 4.
And the outer shell 3.
Then, the welding sheet 5 is sandwiched between the first locking member 8 and the outer shell 3, and these can be welded by electromagnetic induction heating.

In this case, the connection between the outer shell 3 and the inner shell 2 is made by directly locking the first locking member 8 and the locking member 4. Further, since the locking hole 8c of the first locking member 8 of the present embodiment is open to the side, the pin 4b of the locking member 4 is pushed in from this opening to slide the locking member 4. Thus, the locking member 4 and the first locking member 8 may be connected. Also, a first locking member 8 is attached to the inner shell 2, and a separate pin member is fixed to the locking hole 8c of the first locking member 8, and a claw portion at the tip of the pin member is provided. The outer shell 3 and the inner shell 2 may be connected by locking the outer shell 3 into the locking holes 3 a of the outer shell 3. Further, the first locking member 8 is not limited to the inner shell 2 having the locking member 4 welded to the outer shell 3 and the first locking member 8 being welded. The locking member 4 may be welded and welded to the outer shell 3.

Therefore, according to this embodiment, it is possible to increase the degree of freedom in setting and changing the mounting positions of the locking members 4 and 8 with respect to the inner shell 2 and the outer shell 3, and to increase or decrease the number of installation locations. For this reason, for example, the locking members 4 and 8 can be intensively attached to a portion where the connection between the inner shell 2 and the outer shell 3 is particularly reinforced.

Further, in each of the above-described embodiments, the inner shell 2 and the outer shell 3 are connected by the engagement of the pawls and holes of the locking members. However, the present invention is not limited to this. The inner shell 2 and the outer shell 3 may be connected by the connection of the hooks and holes and the engagement of the hooks.

In this embodiment, the structure is the seat 1 of the chair. However, the structure is not limited to this, and may be the backrest 9 of the chair as shown in FIG. Also in this case, the inner shell 2 and the outer shell can be easily formed, and the degree of freedom of the mounting position of the locking member can be increased.

Next, another embodiment of the chair structure of the present invention will be described. As shown in FIGS. 6 and 7, the seat 1 of this embodiment includes an inner shell 2 as a core material, and a back cover that covers the back side of the inner shell 2 and at least partially contacts the inner shell 2. And an outer shell 3. In part of the outer shell 3,
A protruding portion 3 b protruding toward the inner shell 2 is formed. The tip surface of the projection 3b is a contact surface 3d that contacts the inner shell 2. Further, a welding sheet 5 is interposed between the contact surface 3d and the inner shell 2. The contact surface 3d and the inner shell 2 are welded by the welding sheet 5.

Note that the inner shell 2 in this embodiment is
The materials of the cushion 6, the upholstery 7, the outer shell 3, and the welding sheet 5 are the same as those of the embodiments shown in FIGS. The welding of the inner shell 2 and the outer shell 3 by the welding sheet 5 in this embodiment is performed in the same manner as the welding in each embodiment shown in FIGS. 1 to 5. That is, the inner shell 2 and the outer shell 3 and the welding sheet 5 are made of compatible materials. For example, the inner shell 2 and the outer shell 3 are made of polypropylene, and the welding sheet 5 is a sheet material mainly composed of polypropylene and contains iron powder. Then, the iron powder of the welding sheet 5 is heated by electromagnetic induction, and the welding sheet 5, the inner shell 2 contacting the welding sheet 5, and the contact surface 3d are melted and welded.

According to this embodiment, the inner shell 2
And the outer shell 3 are directly welded only by the welding sheet 5, so that the locking member can be omitted, the number of parts can be reduced, and the assembling work of the seat 1 can be simplified, and the manufacturing can be simplified. The cost can be significantly reduced.

Further, in the embodiment shown in FIGS. 6 and 7, a housing groove 10 is formed in the edge 3e of the outer shell 3. The accommodation groove 10 opens toward the inner shell 2 to open the peripheral portion 2 a of the inner shell 2 and the upper fabric 7.
Is accommodated. Therefore, the appearance of the seat portion 1 can be improved by hiding these peripheral portions 2a and 7a. Further, a gap S is provided between the two side walls of the housing groove 10, the inner shell 2 and the upper covering 7.
For this reason, when assembling the outer shell 3 to the inner shell 2, due to a dimensional error of the outer shell 3 and the inner shell 2, the edge 3 e of the outer shell 3 and the peripheral edges 2 a, 7 a of the inner shell 2 and the upholstery 7. To prevent the assembly from becoming impossible due to interference.

Further, the bottom of the housing groove 10 presses the peripheral edge 7 a of the upper covering material 7 against the peripheral edge 2 a of the inner shell 2. This prevents the peripheral edge 7 a of the upper covering 7 from peeling off from the peripheral edge 2 a of the inner shell 2.

On the other hand, in the embodiment shown in FIGS. 6 and 7,
Although the contact surface 3d at the tip of the protrusion 3b of the outer shell 3 is welded to the inner shell 2, it is a matter of course that the present invention is not limited to the formation of the protrusion 3b. For example, in the embodiment shown in FIG. 8 and FIG.
The portion other than e is made to protrude toward the inner shell 2 as a contact portion 3f as a whole, so that the contact portion 3f of the outer shell 3 almost entirely contacts the inner shell 2. The welding sheet 5 is sandwiched between a part of the contact portion between the contact portion 3f and the inner shell 2. The outer shell 3 and the inner shell 2 are welded by the welding sheet 5.

Also in this embodiment, since the inner shell 2 and the outer shell 3 are directly welded only by the welding sheet 5, the locking member can be omitted.
Manufacturing cost can be reduced by reducing the number of parts and simplifying the assembling work of the seat 1.

Further, according to this embodiment, the contact portion 3f of the outer shell 3 may be formed to be entirely flat in conformity with the shape of the inner shell 2 and partially project toward the inner shell 2 side. Since there is no need to form a protruding portion in contact with the outer shell 3, the outer shell 3 can be easily formed.

By the way, the welding sheet 5 in this embodiment
The mounting position of the outer shell 3 and the rigidity of the seat 1
Is set in consideration of the strength of assembling, etc. Positioning of the welding sheet 5 with respect to this set position is performed, for example, by forming a recess slightly recessed from the welding sheet 5 and shallower than the thickness of the welding sheet 5 at the mounting position of the welding sheet 5 on the outer shell 3. This can be performed by placing the welding sheet 5 in the recess. Further, for example, a convex portion which is lower than the thickness of the welding sheet 5 and protrudes toward the inner shell 2 is formed so as to surround the attachment position of the welding sheet 5 of the outer shell 3, and the welding sheet 5 is formed inside the convex portion. Can also be performed by placing Therefore, if the welding sheet 5 is placed inside the concave portion or the convex portion, the positioning is performed, so that the positioning operation can be facilitated.

Further, it is not necessary to place the welding sheet 5 on all of these concave portions and convex portions, and the welding sheet 5 may be mounted by selecting some of the concave portions and convex portions. This allows
The degree of freedom of the number of welding sheets 5 used for welding increases, and the outer shell 3 corresponding to the rigidity required for the seat 1 can be assembled.

It should be noted that the recesses and protrusions are not limited to being formed in the outer shell 3 as described above, and it is a matter of course that the recesses and protrusions may be formed in the inner shell 2.
Then, even if the welding sheet 5 is placed on the concave portion or the convex portion of the inner shell 2, the positioning of the welding sheet 5 can be easily performed.

Further, as shown in FIG. 9, the positioning of the welding sheet 5 with respect to the set position is performed by:
The jig 11 supporting the outer shell 3 on the side opposite to the inner shell 2 is press-fitted and fixed, and the through-hole 3 of the outer shell 3 is fixed.
g, and the positioning holes 5a of the welding sheet 5 fitted to the positioning pins 12 can be used. In this case, when the outer shell 3 is placed on the jig 11, the positioning pins 12
Through the through hole 3g. And this positioning pin 12
The positioning hole 5a of the welding sheet 5 is fitted to the front end of the welding sheet.
As a result, the welding sheet 5 is placed at a predetermined set position. Further, by placing the inner shell 2 on the outer shell 3, the outer shell 3 and the inner shell 2 can hold the welding sheet 5 at a set position.

According to the positioning structure shown in FIG. 9, the position where the through hole 3g is formed in the outer shell 3 and the positioning pin 12
Can be determined after the formation of the outer shell 3, so that the mounting position of the welding sheet 5 can be set after the formation of the outer shell 3. For this reason, the outer shell 3 having no through-hole 3g or having the minimum required number of through-holes 3g is formed, and rigidity and the like required for the seat portion 1, which is a structure of a chair to be assembled. According to the above, the through holes 3g can be increased by post-processing. As a result, the versatility of the outer shell 3 is increased, and component costs can be reduced.

The positioning of the welding sheet 5 with respect to the set position can be performed without providing any positioning shape on the outer shell 3 or the inner shell 2. For example, the welding sheet 5 can be placed at several places on the contact portion 3f of the outer shell 3 and welded to the inner shell 2. According to this, the shapes of the outer shell 3 and the inner shell 2 can be further simplified, and the setting of the mounting position and the number of the welding sheets can be more freely performed.

The edge 3e of the outer shell 3 of this embodiment is also provided on the outer shell 3 of the embodiment shown in FIG.
An accommodation groove 10 having the same shape as that of FIG. Therefore, when assembling the outer shell 3 to the inner shell 2, the edge 3 e of the outer shell 3 and the inner shell 2
In addition, it is possible to prevent the peripheral edges 2a, 7a of the upper covering 7 from interfering with each other and to prevent the assembly, and prevent the peripheral edge 7a of the upper covering 7 from peeling off from the peripheral edge 2a of the inner shell 2.

[0047]

As is apparent from the above description, according to the first aspect of the present invention, since the locking member for connecting the inner shell and the outer shell is separate from each shell, the locking hole is engaged with the locking hole. The part to be formed does not become an undercut in the molding, and the locking hole formed in the other shell can also be made into a shape without undercut, so when forming each shell, consider the undercut at all It can be molded without. Therefore, when the shell is injection-molded, the mold structure can be simplified, and when the mold is opened, the mold may be pulled out in one direction, so that the molding operation is also facilitated. Also, the shell can be formed by, for example, press working in which an undercut cannot be formed. Furthermore, since the locking member and the shell are welded by electromagnetic induction heating, even if the shell and the locking member are formed of a material that is difficult to be bonded with an adhesive, for example, general polypropylene as a structural material of a chair, they can be sufficiently formed. The structure can be formed by being fixed with an appropriate strength.

Also, in the case of the second aspect of the invention, similarly to the first aspect of the invention, the second locking member connecting the inner shell and the outer shell can be formed separately from any of the shells. For this reason, the portion that engages with the locking hole of the first locking member does not become an undercut in molding. Therefore, the same effect as the first aspect of the invention can be obtained. In addition, since the positions at which the first and second locking members are attached to the shells can be arbitrarily set, the degree of freedom of the connecting position between the shells increases, and the number of connecting points can be easily increased or decreased.

Further, according to the third aspect of the present invention, since the inner shell and the outer shell are directly welded by the heat generated from the welding sheet, the inner shell and the outer shell are connected without using a locking member. And it is not necessary to form an undercut shape in any of the shells. Therefore, the same operation and effect as those of the first and second aspects can be obtained, and the number of parts can be reduced by further omitting the locking member. Moreover, since the portions where the shells come into contact with each other are formed a lot, and the position where the welding sheet is attached can be arbitrarily selected from among them,
As the degree of freedom of the connecting position between the shells increases, the number of connecting points can be easily increased or decreased. In addition, since the number of parts can be reduced, the manufacturing operation can be simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a seat showing an embodiment in which a chair structure of the present invention is applied to a seat.

FIG. 2 is a partially omitted bottom view showing an inner shell of a seat portion of a chair.

FIG. 3 is a perspective view showing a locking member.

FIG. 4 is a perspective view showing a first locking member.

FIG. 5 is a partially omitted rear view of the inner shell of the backrest, showing a state in which a locking member is attached to the inner shell.

FIG. 6 is a longitudinal sectional view showing another embodiment of the seat portion of the chair.

7 is a partially omitted longitudinal sectional view showing an enlarged view of a seat portion of the chair of FIG. 6;

FIG. 8 is a longitudinal sectional view showing another embodiment of the seat portion of the chair.

FIG. 9 is a partially omitted longitudinal sectional view showing a structure for positioning a welding sheet on a seat portion of the chair of FIG. 8;

FIG. 10 is a cross-sectional view showing a connection portion of a conventional structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Seat part (structure) 2 Inner shell (core material) 3 Outer shell (back cover) 3a Locking hole 3d Contact surface (part where inner shell and outer shell contact) 3f Contact part (inner shell and outer shell) 4) Locking member (second locking member) 5 Welding sheet 6 Cushion 7 Upholstery 8 First locking member 9 Backrest (structure)

Claims (3)

[Claims] In a structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back side of the inner shell, the chair is formed on one of the inner shell and the outer shell. A locking hole, a locking member to be engaged with the locking hole, and a welding sheet interposed between the other shell and the locking member and capable of generating heat by electromagnetic induction; And one of the shells is welded by heat generation of the welding sheet, and the locking member and the other shell are connected by engagement of the locking member with the engagement hole. Structures such as seats or backrests. 2. A structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back side of the inner shell. A second locking member to be engaged with the locking member, the inner shell or the outer shell, one of the shells, the first locking member, and the other shell and the second locking member. A welding sheet interposed therebetween and capable of generating heat by electromagnetic induction;
And each of the second locking members and the respective shells are welded by the heat generated from the welding sheet, and the first engagement member is engaged by the engagement of the second locking member and the engagement hole of the first locking member. A structure such as a seat portion or a backrest of a chair, wherein the stop member and the second locking member are connected. 3. In a structure such as a seat portion or a backrest of a chair having an inner shell and an outer shell covering a back surface side of the inner shell, at least a part where the inner shell and the outer shell are in direct contact with each other is provided. And a welding sheet interposed between both shells of the contact portion and capable of generating heat by electromagnetic induction, wherein the inner shell and the outer shell are directly welded by the heat generated by the welding sheet. Such as a chair seat or a backrest.