JP5437724B2 - Chair backrest device - Google Patents

Description

  The present invention relates to a chair backrest device that forms a backrest surface by stretching a membrane member having elasticity (hereinafter referred to as an elastic membrane member) on a backrest frame frame that is substantially rectangular in a front view.

The back of the chair is formed by a substantially rectangular back frame frame in front view, and is knitted or woven into a mesh with high tension and elasticity between the frame members facing each other on the top, bottom, left and right of the frame. It is known that an appropriate elasticity is imparted to the backrest surface of the backrest by stretching the elastic membrane member (see Patent Documents 1 and 2).
Also, it is known that the backrest is molded so that the elastic membrane member is stretched with an appropriate tension integrally with the backrest frame frame simultaneously with the formation of the backrest frame frame using the mold. (See Patent Document 3).

However, in the chairs described in each patent document, the elasticity of the backrest surface of the backrest is such that the elasticity of the material of the elastic membrane member itself and the elastic membrane member is stretched over the frame member of the backrest frame frame. Therefore, when the back abutment surface is a flat surface, the position of the seated person's back is not stable when sitting.
Therefore, in order to stabilize the back of the seated person at the time of sitting, as described in Patent Document 2, an arc that curves so that the center part in the left-right direction on the back surface protrudes rearward in a plan view. In addition to deforming into a curved shape in plan view, the left and right side frame members can be bent in a generally “<” shape so that they can protrude forward in side view so that the back of the seated person can be accommodated. It is desirable to make it.

However, the upper and lower frame members forming the backrest frame are arcuately curved rearward in a plan view, and the left and right side frame members are substantially at the front in the vertical direction in the side view. It is formed in a substantially "<" shape that bends toward the end, and the upper and lower side edges of the elastic film-like member are stretched to forcibly form the above-described curved shape in plan view and curved shape in side view. Even if it is going to be deformed, the left and right side edges of the elastic membrane member are also stretched on the left and right side frame members that form the back frame frame, so that the entire peripheral edge of the elastic membrane member is Due to the applied tensile force, in particular, a restoring force is exerted to elastically return toward the front so that the back surface in the vicinity of the bent portion of the side frame member forms a flat surface.
Therefore, in order to forcibly maintain the shape of the back surface in the above-described curved shape of the plan view and the shape of the side view, complicated holding means is separately required. There is a problem that the curved shape cannot be maintained over a long period of time.

Japanese Patent No. 3993375 Design Registration No. 1199426 Japanese Patent No. 3200409

  In view of the above-mentioned present situation, the present invention can maintain the curved shape of the elastic membrane member on the back surface over a long period of time and can maintain a stable and comfortable seating posture. An object is to provide an apparatus.

  The above-described problems are solved by the invention having the following configuration, as described in each claim in the section “Claims”.

(1) The back of a chair formed by a backrest frame frame formed in a substantially rectangular shape in front view by frame members on the top, bottom, left and right, and an elastic membrane member stretched in the backrest frame frame. In the bending apparatus, the left and right side frame members of the back frame frame are formed in a substantially “<” shape in which a substantially intermediate position in the vertical direction bends forward in a side view, and the elastic membrane member is In the side view, the middle position in the vertical direction is stretched so as to form a substantially “<” shape that gently curves forward, and the left and right sides of the lower frame member and the left and right side frames A pair of left and right shape holding members are straddled between the bent portions of the members and obliquely upward to the outside, and the lower portions of the left and right side portions of the elastic membrane member are supported by these shape holding members.

(2) In the above item (1), the bending base point of the elastic membrane member can be positioned higher than the bending base point of the side frame member.

(3) In the above item (1) or (2), the back frame frame, the shape holding member, and the elastic membrane member are integrally molded.

(4) In any one of the above items (1) to (3), the upper frame member is formed in an arc shape that protrudes rearward in a plan view.

(5) In any one of the above items (1) to (3), the upper frame member is formed to be linear in the left-right direction in plan view.

(6) In any one of the above items (1) to (5), the lower frame member is formed in an arc shape that protrudes rearward in a plan view.
The specific contents of the invention are as follows.

According to the present invention, the following effects can be obtained.
According to the first aspect of the present invention, the side frame member of the backrest frame frame is formed in a substantially “<” shape in which a substantially middle position in the vertical direction bends forward in a side view, and the elastic film The side members are stretched so as to form a substantially “<” shape that is gently curved toward the front at a substantially intermediate position in the vertical direction in a side view, A pair of left and right shape holding members are straddled between the bent portions of the side frame members in an obliquely outward direction, and the lower portions of the left and right side portions of the elastic membrane member are supported by these shape holding members. Therefore, the shape-retaining member exerts a restraining force that suppresses the restoring force that the elastic membrane-like member is elastically restored to a flat surface, so that the elastic membrane-like member on the back surface does not have a complicated structure. Side view curve shape for a long time It can be maintained.
In addition, since the shape holding member is straddled between the vicinity of the left and right side portions of the lower member and the bent portions of the left and right side frame members, the shape holding member is It is possible to maintain a stable and comfortable sitting posture without causing discomfort such as hitting the hip bone of the seated person.

  According to the invention described in claim 2, since the bending base point of the elastic membrane member can be positioned higher than the bending base point of the side frame member, in the seated state, in the vicinity of the lower part of the hip bone of the seated person. Positioned above the bending base point of the side frame member at the corresponding position, the lumbar portion of the seated person is pressed, and a stable seating posture with the back muscles stretched can be maintained.

  According to the invention of claim 3, since the back frame frame, the shape holding member, and the elastic membrane member are integrally molded, the support strength of the elastic membrane member by the back frame frame and the formed holding member And the elastic restoring force of the elastic membrane member can be suppressed.

  According to the invention described in claim 4, since the upper frame member is formed in an arc shape projecting rearward in a plan view, the elastic membrane member is rearwardly directed by the shape holding member. The elastic membrane member can be supported so as to be pressed, and can exert a large force in the restraining direction with respect to the direction in which the elastic return force of the elastic membrane member is generated. Can be stably maintained in an arc shape that curves backward in plan view.

  According to the invention of claim 5, since the upper frame member is formed so as to be linear in the left-right direction in plan view, the back surface of the elastic film-like member tries to approach a flat surface, A force in a restraining direction that pushes the elastic membrane member forward can be applied to the restoring force that tries to push backward by the shape holding member.

  According to the invention of claim 6, since the lower frame member is formed in an arc shape protruding rearward in plan view, the lower end edge of the elastic membrane member is directed rearward in plan view. The curved shape of the elastic film-like member forming the back contact surface can be more effective over a long period of time, in combination with the effect of claim 4. Can be maintained.

It is a perspective view of the chair provided with the backrest apparatus of one Embodiment in this invention. (Example) Similarly, it is a rear view of a chair. It is a center longitudinal cross-sectional view which shows the seating state to the chair of the III-III line in FIG. It is a disassembled perspective view of a chair. FIG. 5 is an enlarged longitudinal sectional view of a seat body taken along line VV in FIG. 4. FIG. 6 is an enlarged longitudinal sectional view of a seat body taken along line VI-VI in FIG. 4. FIG. 7 is an enlarged longitudinal sectional end view of a seat body taken along line VII-VII in FIG. 4. It is an expanded transverse end view of the backrest of the VIII-VIII line in FIG. FIG. 6 is an enlarged cross-sectional end view of the backrest of line IX-IX in FIG. 4. FIG. 5 is an enlarged longitudinal sectional end view of the backrest of line XX in FIG. 4. FIG. 5 is an enlarged longitudinal sectional end view of the backrest of the XI-XI line in FIG. 4.

An embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view of a chair according to an embodiment of the present invention, FIG. 2 is a rear view of the chair, and FIG. 3 is a central longitudinal sectional view showing a seated state of the chair taken along line III-III in FIG. FIG. 4 is an exploded perspective view of the chair.

  As shown in FIGS. 1 to 4, the chair 1 of the present invention includes a pair of left and right side legs 3, 3 formed by bending a leg 2 into a substantially rectangular frame shape in a side view. The left and right side legs 3 and 3 are formed with a pair of front and rear connecting rods 4 and 5 that connect the upper portions of the left and right side legs 3 and 3, and a seat body 6 is attached to the upper surface of the leg body 2. It is constituted by mounting the backrest 7 upright on the rear part.

  The seat body 6 is formed of a seat frame frame 8 made of a synthetic resin material such as polypropylene, for example, by a front and rear frame members 8A and 8B and left and right frame members 8C and 8C in a substantially rectangular shape in plan view. For example, the peripheral edge of the elastic membrane member 9 formed by knitting or weaving polyamide fiber or polypropylene fiber in a mesh shape is stretched on the inner peripheral surfaces of the members 8A to 8C by integral molding.

  5 is an enlarged longitudinal sectional view of the seat body taken along the line VV in FIG. 4, FIG. 6 is an enlarged longitudinal sectional view of the seat body taken along the line VI-VI in FIG. 4, and FIG. FIG. 8 is an enlarged longitudinal sectional end view of the seat of the line VIII-VIII in FIG.

  As shown in FIGS. 5 to 8, the elastic membrane member 9 has a front end edge 9 a on the inner peripheral surface of the front frame member 8 </ b> A in the seat frame frame 8 and a rear end edge 9 b on the rear portion in the seat frame frame 8. The left and right side edges 9c, 9c are supported on the inner peripheral surface of the left and right side frame members 8C, 8C in the seat frame frame 8, respectively, on the inner peripheral surface of the frame member 8B.

As shown in FIGS. 5 and 6, the front frame member 8 </ b> A is formed with a front tongue piece 10 extending in an arc shape toward the rear upper side in a side view. The front side of the elastic membrane member 9 is held on the upper surface of 10.
As shown in FIG. 7, the front tongue piece 10 has an arc-shaped front-view cross-sectional shape that protrudes downward and curves from the center in the left-right direction toward the left and right side frame members 8C and 8C, respectively. The rear end portion 10a is curved downward so as not to directly contact the lower surface of the elastic membrane member 9.
As a result, as shown in FIG. 3, the front tongue piece 10 sinks into the recessed portion 12 described later by the buttocks due to the load when the seated person is seated, and the lower portions of the left and right thighs are the front tongue piece 10. Are bent downward together with the elastic membrane member 9 so as to be able to come into contact with the arc-shaped left and right concave surfaces projecting downward, thereby providing a cushioning action against the load of the seated person.

The rear frame member 8B has a gentle arc shape that curves backward in a plan view and a gentle arc shape that curves downward in a rear view. A rear tongue piece 11 having a substantially trapezoidal shape with the length of the front side being smaller than the length of the rear side is formed.
The rear tongue piece 11 is formed so that the front side corresponding to the front end portion 11a has a gentle arc shape that curves backward in plan view, and is positioned below the upper surface of the rear frame member 8B. As shown, it is curved and extended forward and downward.

That is, the front end portion 11a of the rear tongue piece 11 supports the central portion in the left-right direction of the rear end edge 9b of the elastic membrane member 9, and as shown in FIG. It can be supported in a shape that forms a gentle arc that gradually curves downward from the left and right sides toward the center.
As a result, as shown in FIG. 5, the elastic membrane member 9 has a central portion in the left-right direction of the front tongue piece 10 extending in an arc shape from the front frame member 8 </ b> A toward the rear upper side in a side view. It is stretched so as to form a gentle arc connecting from the highest point P of the front part held above to the lowest point Q of the rear part supported by the front end part 11a curved downward of the rear tongue piece 11. As a result, the depth gradually increases from the rear end portion 10a of the front tongue piece 10 at the substantially intermediate portion in the front-rear direction on the seating surface of the seat body 6 toward the front end portion 11a of the rear tongue piece 11 of the rear frame member 8B. A recessed portion 12 is formed, and the recessed portion 12 is configured to securely hold the seated person's buttocks and thighs together with the above-described cross-sectional shape of the front tongue piece 10 so as not to be shifted left and right. .

As shown in FIG. 6, the side frame member 8 </ b> C is rearwardly upward from the front highest point R that forms an arc shape that is upward and rearward, via the intermediate point that is downward and downward, and the lowest point S that is rearward. The lowermost point Q of the rear portion of the elastic membrane member 9 supported by the front end portion 11a of the rear tongue piece 11 is formed in a shape that can be supported so as to form a gentle arc shape. The side frame member 8 </ b> C supporting the side edge in the left-right direction can be positioned behind and below the lowest point S of the rear part of the side frame member 8 </ b> C.
As a result, the concave portion 12 is positioned so that the highest point R of the side frame member 8C is higher than the central portion of the front tongue piece 10 in the left-right direction. The bottom point Q of the rear part of the elastic membrane member 9 supported by the front end part 11a of the rear tongue piece 11 is the lowermost part of the rear part of the side frame member 8C. Since it is located behind the point S, the shape from the highest point R to the lowest point S of the side frame member 8C sinks downward without expanding rearward in a plan view. None and downward from the lowest point S of the side frame member 8C toward the front end portion 11a of the rear tongue piece 11 which is the lowest point Q of the rear portion of the elastic membrane member 9 while gradually narrowing in plan view. It has a shape that sinks, and when sitting, the seated person's buttocks fit better and is more stable Can you keep the seating posture.
Further, the side frame member 8C has a gentle upward arc shape in the rear upward direction from the highest point R of the front part that forms a rear upward arc shape through the intermediate part in the rear downward direction and the lowest point S in the rear part in a side view. Since it is formed in a shape that can be supported so as to form an aesthetic feature, the aesthetics of the seat can be enhanced.
Further, the lowermost point Q of the rear end of the elastic membrane member 9 which is the front end portion 11a of the rear tongue piece 11 is set to the rear portion of the side frame member 8C on which the lateral edge of the elastic membrane member 9 is supported. Since the center portion in the left-right direction of the elastic membrane member 9 is returned to a horizontal state so as to become a flat surface by a tensile force because the lowermost point S can be positioned below, A shape forcing force stronger than the shape forcing force due to the side view shape of the side frame member 8C can be applied, and the shape of the recessed portion 12 can be stabilized.
Further, since the side edge of the elastic membrane member 9 in the left-right direction can be positioned behind the lowest point S of the rear portion of the side frame member 8C to be supported, the shape of the recessed portion 12 in plan view is The shape can be gradually bent backward from the rear portion of the side frame member 8C toward the rear tongue piece 11, and can be easily matched with the planar view and the side view shape of the rear frame member 8C. Can do.

Similar to the above-described seat body 6, the backrest 7 is made of a synthetic resin backrest frame frame 13 made of, for example, polypropylene or the like, and is substantially rectangular in front view by the upper and lower frame members 13A and 13B and the left and right frame members 13C and 13C. While being formed into a shape, the peripheral edge of the elastic membrane member 14 formed by knitting or weaving polyamide fiber, polypropylene fiber, or the like in a mesh shape is supported and stretched on the inner peripheral surface of each of the frame members 13A to 13C. Thus, a back surface is formed.
As shown in FIG. 4, the backrest 7 has mounting holes 15 provided at the lower ends of the left and right frame members 13 </ b> C and 13 </ b> C in the backrest frame frame 13, and rear legs 3 a of the left and right side legs 3 in the leg body 2. , 3a so as to be able to stand up to the rear part of the seat body 6 by being inserted into support rods 16 and 16 provided so as to protrude upward from the upper end of the seat body 6.

As shown in FIGS. 1 and 2, the upper frame member 13 </ b> A and the lower frame member 13 </ b> B in the back frame frame 13 are formed in an arc shape that curves so as to protrude rearward in plan view.
As shown in FIG. 3, the left and right side frame members 13 </ b> C are each formed in a substantially “<” shape in which a substantially middle position in the vertical direction bends forward in a side view.

As shown in FIGS. 1, 2, and 4, the backrest frame 13, between the vicinity of the left and right sides of the lower frame member 13 </ b> B and the bent portion 13 a of the left and right side frame members 13 </ b> C and 13 </ b> C, A pair of left and right shape holding members 17, 17 are provided so as to be obliquely upward and outwardly arranged so as to be bilaterally symmetrical, and these shape holding members 17 are provided on both left and right sides of the elastic membrane member 14. The lower part of the part is supported.
The shape holding member 17 is formed integrally with the backrest frame frame 13 and the elastic membrane member 14 when the backrest 7 is molded.

  9 is an enlarged transverse end view of the backrest of the IX-IX line in FIG. 4, FIG. 10 is an enlarged transverse end view of the backrest of the XX line in FIG. 3, and FIG. 11 is an XI-XI in FIG. It is an expanded vertical end view of the backrest of a line.

  As shown in FIGS. 9 to 11, the elastic membrane member 14 stretched on the back frame 13 has an upper end edge 14a on the inner peripheral surface of the upper frame member 13A and a lower end edge 14b on the lower frame member 13B. The left and right side edges 14c are supported on the inner peripheral surface of the inner peripheral surface of the side frame member 13C, and the substantially intermediate position in the vertical direction is curved gently toward the front in a side view. (See FIG. 11), and in a plan view, it is stretched to form an arc shape that curves so as to protrude rearward (see FIG. 9).

According to the configuration of the backrest 7 described above, between the vicinity of both lateral sides of the lower frame member 13B forming the backrest frame frame 13 and the bent portions 13a of the left and right side frame members 13C and 13C, respectively. By stretching the shape holding member 17 so as to support the lower portions of the left and right side portions of the elastic membrane member 14 (see FIG. 10), as shown in FIG. The elastic return force forward generated in the vicinity of the bent portion 13a of the left and right side frame members 13C on both the left and right side portions, that is, the upper frame member 13A is formed in an arc shape that curves so as to protrude rearward in plan view. As a result, a restraining force (indicated by an arrow in FIG. 11) that suppresses a tensile force that tends to approach a flat surface toward the front works.
In other words, the shape holding member 17 supports the elastic membrane member 14 so that the rear surface of the elastic membrane member 14 is pressed forward, whereby a force in the restraining direction is generated with respect to the direction in which the elastic membrane member 14 generates the elastic restoring force. Can be greatly increased.
Thereby, in particular, it is possible to maintain the curved shape of the side view of the elastic membrane member 14 in the vertical direction between the bent portions 13a of the left and right side frame members 13C over a long period of time.

Further, since the curved base point C of the elastic membrane member 14 is supported by the shape holding member 17 at the lower portions of the left and right side portions, as shown by the broken line in FIG. 11, the bending base point C ₀ of the side frame member 13C. 3, that is, in the sitting state shown in FIG. 3, the lumbar portion of the seated person is positioned above the bending base point C ₀ of the side frame member 13 </ b> C at a position corresponding to the vicinity of the lower part of the seated person's hipbone. It is possible to obtain a stable seating posture with the back straight.

  In the above embodiment, the upper frame member 13A is formed in an arc shape that curves so as to protrude rearward in a plan view, whereby the elastic film-shaped member 14 is stretched to stretch the elastic film-shaped member. 14, the elastic restoring force forward can be generated in the vicinity of the bent portion 13a of the left and right side frame members 13C. However, when the upper frame member 13A extends linearly in the left-right direction in plan view. No elastic restoring force is generated forward, and conversely, a backrest surface of the elastic membrane member 14 tries to approach a flat surface and a restoring force is generated to push downward. On the other hand, a force in a restraining direction that pushes the elastic membrane member 14 forward is applied by the left and right shape holding members 17, and the side view curve shape of the elastic membrane member 14 in the vertical direction is maintained for a long time. Making it possible.

DESCRIPTION OF SYMBOLS 1 Chair 2 Leg 3 Side leg 3a Rear leg 4, 5 Connecting rod 6 Seat body 7 Backrest 8 Seat frame frame 8A Front frame member 8B Rear frame member 8C Side frame member 9 Elastic film member 9a Front edge 9b Rear End edge 9c Side edge 10 Front tongue piece 10a Rear end portion 11 Rear tongue piece 11a Front end portion 12 Recessed portion 13 Backrest frame frame 13a Bending portion 13A Upper frame member 13B Lower frame member 13C Side frame member 14 Elastic membrane member 14a Upper end edge 14b Lower end edge 14c Side edge 15 Mounting hole 16 Support rod 17 Shape retaining member C Curved base point C of elastic membrane member ₀ Bend base point of side frame member Maximum point Q of elastic membrane member Front elastic membrane member The lowest point R of the rear part The highest point of the front part of the side frame member S The lowest point of the rear part of the side frame member

Claims (6)

In a chair backrest device, the backrest is formed by a backrest frame frame formed in a substantially rectangular shape in front view by upper, lower, left and right frame members, and an elastic membrane member stretched in the backrest frame frame. ,
The left and right side frame members of the backrest frame frame are formed in a substantially square shape in which a substantially intermediate position in the vertical direction is bent forward in a side view, and the elastic membrane member is The middle position in the direction is stretched so as to form a generally square shape that gently curves forward, and between the vicinity of the left and right side portions of the lower frame member and the bent portion of the left and right side frame members A backrest of a chair characterized in that a pair of left and right shape holding members are straddled in an obliquely upward direction to the outside, and the lower portions of the left and right sides of the elastic membrane member are supported by these shape holding members. apparatus.   2. The chair backrest device according to claim 1, wherein the bending base point of the elastic membrane member can be positioned higher than the bending base point of the side frame member.   The chair backrest device according to claim 1 or 2, wherein the backrest frame, the shape holding member, and the elastic membrane member are integrally molded.   The chair backrest device according to any one of claims 1 to 3, wherein the upper frame member is formed in an arc shape protruding rearward in a plan view.   The chair backrest device according to any one of claims 1 to 3, wherein the upper frame member is formed so as to be linear in the left-right direction in plan view.   The chair backrest device according to any one of claims 1 to 5, wherein the lower frame member is formed in an arc shape protruding rearward in a plan view.

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