JP7217105B2 - Chair - Google Patents

Description

The present invention relates to a chair with a movable seat.

Chairs in which the seat tilts back against elastic means are widely used. Regarding the relationship with the backrest, there are cases where the seat tilts backward independently and cases where the seat tilts backward in conjunction with (synchronized with) the rearward tilting movement of the backrest. Furthermore, in relation to the backrest, the seat and the backrest are integrally connected and both tilt backward at the same angle, or the rearward tilt angle of the backrest and the seat tilt differently. The former is common in sofa types, and the latter is common in swivel chairs.

As for the elastic means, there are cases where a metal spring such as a coil spring is used and where rubber is used. Since the rubber material is easy to handle, it can be said that the number of cases where it is used has increased in recent years as the quality of the material has improved.

As an example, Patent Literature 1 describes U-shaped brackets that face each other vertically and are connected by left and right long pins. It is disclosed that the body is placed with the left and right sides of the upper surface of the body in intimate contact with the inner surface of the fixture.

Patent Document 2 discloses a chair whose seat is circular in plan view and can be tilted in any direction. A technique has been disclosed in which even if the camera is tilted, the tilt can be supported by one elastic body.

Japanese translation of PCT publication No. 2017-534380 JP 2006-68223 A

In Patent Document 1, since the swelling deformation of the elastic body is restrained by the fixture, the rate of increase of the elastic resistance of the elastic body becomes higher than the rate of increase of the tilting angle of the seat (that is, as the rearward tilting angle of the seat increases, , the elastic modulus of the elastic body increases.) Therefore, it can be said that a large load can be supported. Therefore, it is understood that this is suitable for chairs such as rocking chairs in which the backrest and the seat are integrally continuous, in which a large moment acts on the elastic body.

However, in the case of a chair in which the seat and the backrest are separated, there is a limit to the moment that acts on the seat when the seated person leans against the backrest. There is a possibility that the rearward tilting motion of the seat may become insufficient without deformation, and as a result, there is concern that comfort (cushioning properties) may be reduced.

In other words, if the seat and backrest are integrated, the seat will also tilt backwards when you lean back against the backrest. Otherwise, there is a risk that the cushioning property will be insufficient and the sitting comfort will be poor. On the other hand, the chair of Patent Document 2 does not have a backrest, and is difficult to apply to a chair with a backrest.

The present invention has been made in view of such circumstances, and aims to provide a chair with a backrest that can support the rearward tilting of the seat with an appropriate reaction force.

The present invention includes various configurations, typical examples of which are specified in each claim. Of these, the invention of claim 1 is
"A seat and a backrest that are separated from each other are provided, and the seat is pivotally supported on a seat support placed below the seat so that the seat is tilted at least backward by deforming the rubber elastic body. Connected by pins
In the basic configuration of
"The elastic body is sandwiched in an unrestrained state from the outer periphery by an upper bracket provided on the lower surface of the seat and a lower bracket provided on the upper surface of the seat support ,
The elastic body is formed with a positioning hole that is open on the upper surface, the lower surface, or both upper and lower surfaces so as not to penetrate vertically,
Either or both of the upper and lower brackets are provided with positioning projections that enter the positioning holes and hold the elastic body so as not to move laterally.
It is configured.

The orthodox mode of deformation of the elastic body is that it is compressed by a load from above (in the vertical direction) and bulges in the outer peripheral direction. It is also possible to adopt a mode (that is, Hytrel type) in which a beam-like projection is formed and this projection is bent and deformed. Alternatively, it is also possible to form annular flanges at both upper and lower ends of the columnar portion, and to utilize bending deformation of the flanges to elastically support the tilting motion of the seat.

The invention of claim 2 is, in claim 1 ,
"The seat support is composed of a front frame extending from a base provided at the upper end of the leg support toward the front of the seat in an inclined posture when viewed from the side, and the lower bracket is provided at the upper end of the front frame. while
The seat has a structure in which a seat cushion material is superimposed on the upper surface of an inner seat shell made of synthetic resin, and the upper bracket made of sheet metal is fixed to the lower surface of the inner seat shell,
In addition, the upper bracket and the lower bracket are connected by the left and right longitudinal pivot pins, and the elastic body is arranged at least behind the pivot pins."
It is configured.

The invention of claim 3 is a preferred embodiment of claim 2 ,
"A recessed groove into which the upper bracket is fitted is formed in the lower surface of the seat inner shell, and the pivot pin is held by the recessed groove so as not to come off."
It is configured.

When the seat and backrest are separated, when a seated person leans against the backrest, most of the moment is supported by the backrest and the load acting on the seat is not so large. Therefore, it is necessary for the elastic body to be properly deformed even with a load that is not so large. The elastic body is compressed by the bracket and deforms freely. Therefore, it is ensured that the seat is tilted backward against the elasticity of the elastic body, and the user can obtain high comfort. That is, it is possible to prevent the resistance of the elastic body from becoming too strong against the rearward tilting of the seat, thereby ensuring the rearward tilting of the seat, and as a result, improving comfort.

In particular, since the seat can be tilted backwards independently of the backrest, it is easy to tilt the seat backwards when sitting. By improving the fit and cushioning of the product, you can easily achieve high comfort.

The elastic body must be positioned by some means. In this regard, it is possible to enclose the upper end or lower end of the elastic body with a stopper from the outer periphery. There is a risk that the durability will be reduced without deformation.

On the other hand, if positioning holes are provided in the elastic body as in the present invention , the entire outer periphery of the elastic body is allowed to deform, so that the entire elastic body can be uniformly deformed and high durability can be ensured. .

When the positioning hole is formed in a recessed shape as in the present invention , there is an advantage that the elastic body can be made compact, and the elastic body can be prevented from being excessively compressed, so that the tilting motion of the seat can be supported accurately. Depending on the material and size of the elastic body, it can be formed in a cylindrical shape.

By forming the elastic body so that the cross-sectional area gradually changes from top to bottom (or from bottom to top), or by forming the elastic body in the shape of a drum with an inflated intermediate portion, the seat It is also possible to configure so that the elastic modulus changes according to the rearward tilt angle (the rate of increase in resistance is greater than the rate of increase in the rearward tilt angle). With this configuration, there is an advantage that impact can be absorbed by the damper effect.

In claim 2 , since the seat tilts backward with its front part (the part in front of the front-rear middle position) as a fulcrum, the seat becomes a cantilever beam, and when the seat is normally seated, the moment causes the seat to tilt backward. works. Therefore, it can be said that the seat can be easily tilted backward, and the comfort can be improved.

On the other hand, the seat often has a structure in which a seat cushion is stretched over a seat inner shell (seat plate) made of synthetic resin. If the upper bracket is connected to the lower bracket in this state, a large load is applied to the narrow portion of the upper bracket, and there is a risk that the strength cannot be maintained.

On the other hand, in the structure of claim 2 , since the upper bracket is made of sheet metal, even if the seat is in a cantilever state, high strength can be ensured without causing damage or deformation of the seat inner shell. can be done. Therefore, it is excellent in reality. In particular, if the upper bracket is formed in a long shape so as to protrude behind the lower bracket as in the embodiment, the support strength of the seat can be remarkably increased, which is preferable.

In addition, if the upper bracket is formed integrally with the seat inner shell, it is troublesome to attach the pivot pin. Then, for example, it is possible to adopt a procedure of first inserting the pivot pin into the upper bracket and then screwing the upper bracket to the seat inner shell, which facilitates assembly.

Further, in Patent Document 1, since the support unit incorporating the elastic body is fixed to the upper end of the leg strut (gas cylinder), the position of the rear tilting fulcrum of the seat is naturally limited. Although there is little freedom in selecting the tilting point, if the configuration in which the seat is connected to the front frame is adopted as in claim 4 of the present application, the size and shape of the front frame can be freely set, so the rearward tilting point of the seat can be set. Excellent freedom of choice.

Further, in Patent Document 1, since the area of the support unit in which the elastic body is built is small, in order to maintain the strength of the seat, it is necessary to increase the thickness of the shell body constituting the seat or make it metal. However, if the front frame is adopted as in claim 2 of the present application, the seat can be stably supported over a wide span by providing front frames on the left and right sides as in the embodiment. can. Therefore, even if the seat inner shell is made of synthetic resin, it is not necessary to form it excessively thick, and high quality can be ensured while suppressing costs.

In the present invention, it is also possible to tilt the seat forward. In this case, the elastic body should be placed in front of the pivot pin. Unlike claim 4, the seat can be tilted back and forth in a seesaw configuration by connecting the seat to the lower bracket with a pivot pin at the front and back intermediate portion. Further, when tilting in both the forward and backward directions, it is possible to make the strength of the elastic body different between the backward tilting and the forward tilting.

Using a rubber-like elastic body as in the present invention facilitates handling. When the configuration of claim 3 is adopted, the strength of the seat inner shell can be improved by the rib effect of the concave grooves. In addition, since the recessed groove functions as a stopper for retaining the pivot pin, a retaining member such as a slip ring is not required, and the number of components can be reduced accordingly, contributing to cost reduction.

In the external view of the embodiment, (A) is a perspective view with armrests, (B) is a perspective view with no armrests, (C) is a rear perspective view, and (D) is a seat. FIG. 4 is a perspective view in a separated state; (A) is a plan view, (B) is a side view, (C) is a front view, and (D) is a rear view. (A) is an exploded perspective view, (B) is a perspective view of the seat viewed from below, and (C) is a bottom view. It is a figure which shows the attachment structure of a flame|frame, (A) is an isolation|separation perspective view in the state turned over, (B) is an isolation|separation perspective view seen from the top. FIG. 4 is an exploded perspective view showing the relationship between the base and the frame; FIG. 4 is an exploded perspective view showing the mounting structure of the seat; (A) is an exploded perspective view showing support means for the seat, and (B) is a perspective view of the tilting unit in an overturned state. (A) is a cross-sectional view seen from the VIII-VIII direction of FIG. 6, and (B) is a front view of the seat tilting unit .

(1). Overview Next, embodiments of the present invention will be described. This embodiment is applied to a swivel chair used in an office or the like. First, an outline of the chair will be described with reference to FIGS. 1 to 3. FIG. The chair has a seat 1, a backrest 2 and a leg device 3. The leg device 3 includes five branch rods and leg struts 4 (gas cylinders). Casters are provided at the ends of the respective branch rods, while a base 5 (see FIG. 3) is attached to the upper end of the leg struts 4. It's stuck. The leg support 4 is arranged slightly behind the front-back midpoint of the seat 1. - 特許庁

The base 5 is in the form of a rectangular block (horizontally long rectangle) in plan view, and the left and right front frames 6 and the left and right rear frames 7 are fixed to the base 5 so that the seat 1 can be tilted back and forth on the front frames 6. The backrest 2 is attached to the rear frame 7 so as to be tiltable backward. The front frame 6 is therefore an example of a seat support.

As shown in FIGS. 1A and 2C, an armrest 8 can be attached to the upper end of the rear frame 7 as an optional item. The bottom view of FIG. 3(C) shows a state in which the armrest 8 is attached only to one side. For example, as shown in FIG. 3(B), a lever 9 for adjusting the height of the seat 1 is arranged in a posture extending laterally from below the base 5 .

As clearly shown in FIGS. 2(B) and 2(C), the left and right rear frames 7 are slanted so as to shift forward as they go up in side view, and the distance between them increases as they go up in front view. It is slanted so that it spreads out. The reason why the front frame 6 is tilted forward is that the base 5 has a minimum front-to-rear width and is positioned slightly behind the front-to-rear middle point of the seat 1. This is because the portion closer to the front end is attached to the front frame 6 .

The reason why the front frame 6 is slanted outward when viewed from the front is that while the base 5 may be of a minimum necessary size, in order to stably support the seat 1, the distance between the upper ends of the left and right front frames 6 is small. This is because a certain amount of dimension is required for the interval between .

As clearly shown in FIG. 2(B), the rear frame 7 stands up from the base 5 in a backward-leaning posture in a side view, and bends into a dogleg shape so as to change to a forward-leaning posture at approximately the height of the seat 1. When viewed from the front, as shown in FIG. there is

The upper part of the rear frame 7 is positioned on the left and right outside of the lower part of the backrest 2, and the backrest 2 is attached to the upper end part of the rear frame 7 so as to tilt backward with the lower part as a fulcrum. Therefore, the fulcrum (rotation center) of the backrest 2 is positioned within the thick portion of the backrest 2 .

Since the base 5 is much smaller than the seat 1 in a plan view and is arranged below the front and rear halfway of the seat 1, the lower half of the front frame 6 and the rear frame 7 are shown in FIGS. As shown in 3(C), it is slanted in a front view and a side view so as to expand in a diagonal direction. In other words, the front frame 6 and the rear frame 7 are raised in a substantially diagonal direction from the corners of the square base 5 in plan view. In other words, the four frames 6, 7 appear to converge below the seat 1 toward the base 5. As shown in FIG.

The left and right front frames 6 are aluminum die-cast products or resin-molded products, and are integrally formed with a front substrate 6a that is approximately square (horizontally long rectangle) in a plan view. On the other hand, the left and right rear frames 7 are separated from each other, and are integrally formed with rear base bodies 7a each having a substantially rectangular shape in plan view. The left and right rear base bodies 7a overlap so as to be continuous in the left-right direction, and the left and right rear base bodies 7a and the front base bodies 6a overlap in the front-rear direction.

Therefore, the front substrate 6a and the left and right rear substrates 7a are overlapped as if forming one member as a whole, and the base 5 is completely covered by these three. Therefore, the two front frames 6 and the two rear frames 7 have an appearance as if they stand up in a diagonally inclined posture from the substantially rectangular base in plan view, and the base 5 does not overturn the chair. and cannot be visually recognized.

(2) Design Effect In this way, the front frame 6 and the rear frame 7 are visible, and the bases 6a and 7a of both are also visible especially in the rear view, but the bases 6a and 7a are the seat 1 and the base 1. Since there is no member other than the frames 6 and 7 and only a space between them, the design is very simple.

Further, since the front frame 6 and the rear frame 7 as a whole are inclined so as to expand in the diagonal direction, the seat 1 and the backrest 2 are firmly supported. Therefore, the observer can perceive an image of simplicity and high stability. From another point of view, since the four frames 6 and 7 converge toward the base 5 from the diagonal direction of the seat 1, the support function of the seat 1 and the backrest 2 is secured while eliminating waste. It can be said that it has an excellent design in terms of both function and aesthetics.

The backrest 2 is separated from the seat 1, and there is a slight gap between the lower end of the backrest 2 and the seat surface. The backrest 2 is tilted slightly backward as a whole in the neutral state, but the lower part is curved forward so that the part that hits the waist of the seated person is the most forward, and the rocking rotation fulcrum is , located at the height of the most forward part.

Also, the upper half of the rear frame 7 can be formed in an upright posture when viewed from the side, but the lower portion of the backrest 2 is curved when viewed from the side, and the portion below the apex of the curve is tilted forward. Therefore, when the upper half of the rear frame 7 is tilted forward as in the embodiment, the rear frame 7 is tilted, as can be understood from FIGS. 1(B), 2(B) and 3(A). Since the upper part of the backrest 2 overlaps the outer surface of the lower end part of the backrest 2 in substantially the same posture, a sense of unity in posture appears and a refreshing aesthetic effect is exhibited.

The backrest 2 can be tilted backwards, and the seat 1 can be tilted backwards and forwards. In FIG. 2B, the pivot point (rotation center) O1 of the backrest 2 and the pivot point (rotation center) O2 of the seat 1 are shown.

Although not illustrated, the backrest 2 has a structure in which a back cushion is stretched on the front surface of an inner back shell made of synthetic resin. An elastic support unit is arranged in this concave portion, and the elastic support unit and the upper end of the rear frame 7 are connected by laterally long pivot pins. Therefore, the fulcrum of rotation of the backrest 1 is located in the thick portion thereof.

Although the tilting structure of the seat 1 will be described later, the pivot point O2 is displaced toward the front side of the seat 1 . Therefore, the seat 1 is in the state of a cantilever with the rear end being a free end. Further, the rotation fulcrum O2 of the seat 1 is also located within the thick portion of the seat 1 .

If a downward bracket were provided on the lower surface of the seat 1 and connected to the front frame 6 at a portion below the lower surface of the seat 1, the seat 1 would tend to recede while tilting backward, but the main seat support body would not. , Since the center of rotation O2 of the seat 1 is located within the thickness portion, the seat 1 does not retreat even if it tilts backward (strictly speaking, the upper surface of the seat 1 moves backward due to the rearward tilt, but The amount is so small that it can be ignored.). Therefore, even if a person sits down and the seat 1 tilts backward, the seated person does not move backward, and the seated person does not feel uncomfortable.

(3) Frame Attachment Structure Next, the attachment structure of the front frame 6 and the rear frame 7 to the base 5 will be described mainly with reference to FIGS.

The base 5 is an aluminum die-cast product in the form of a block that is horizontally long, and has a center hole 10 in the center for fitting the upper end of the leg support 4 . A pair of left and right front concave portions 11 are formed in the front portion of the upper surface of the base 5, and a rear concave portion 12 is formed in the rear portion thereof. The base 5 is formed with a large number of upward grooves for uniform thickness and material saving (it can also be seen that a large number of ribs are formed inside the base 5).

The front concave portion 11 and the rear concave portion 12 are formed in a quadrangular shape in plan view. A front concave portion 11 is cut in the front surface of the base 5 , and a rear concave portion 12 is surrounded by the base 5 . Further, the front concave portion 11 is located slightly inside the left and right outer surfaces of the base 5 , while the rear concave portion 12 is arranged closer to the left and right side portions of the base 5 .

A front convex portion 13 is formed on the lower surface of the front base body 6a of the front frame 6 so as to fit tightly into the front concave portion 11 of the base 5. 5 with a front bolt 14. Similarly, the rear base body 7a of the rear frame 7 is formed with rear protrusions 15 that tightly fit into the rear recesses 12 of the base 5. are fixed to the base 5 by rear bolts 16, respectively.

Mounting holes 18 through which the bolts 14 and 16 are inserted are provided in the front base 6a and the rear base 7a.

The rear base body 7a is arranged so as to slightly overlap the left and right side portions and the rear portion of the upper surface of the base 5, and has a portion located behind the base 5 and a portion located on the left and right outside of the base 5. part. Therefore, the rear base body 7a is formed in an L shape in plan view, and the rear projections 15 are formed at the inner corners thereof.

On the other hand, the front base body 6a is formed with a rear eaves plate 19 covering the space surrounded by the left and right rear frames 7, and the rear convex portion 15 is covered with the rear eaves plate 19. - 特許庁Therefore, the rear bolt 16 cannot be visually recognized from the outside, and since the head of the rear bolt 16 is also inserted into the mounting hole 18, it is hardly visible.

With such consideration, the front frame 6 and the base 5 appear as if they were integrally molded, contributing to the formation of a simple and beautiful appearance. Further, since the front frame 6 and the left and right rear base bodies 7a are separate members, the mold for manufacturing can be made as small as possible. Therefore, manufacturing is easy. The reason why the rear frame 7 is separated into left and right is that the rear frame 7 is taller than the front frame 6, and the mold becomes considerably large if integrally molded. The rear base 7a is formed with a receiving piece 20 on which the rear eaves plate 19 of the front base 6a rests.

The front frame 6 is manufactured by a mold apparatus having a main molding die that moves relatively vertically with respect to the direction of the chair. It is manufactured in a mold apparatus equipped with a main mold that As can be understood from FIG. 4A, the front frame 6 protrudes forward from the front surface of the base 5, and a relief recess 21 is formed on the lower surface of this forward protruding portion for weight reduction and uniform thickness. forming.

Since the concave portions 11 and 12 of the base 5 and the convex portions 13 and 15 of the frames 6 and 7 are formed in a rectangular shape and are fitted to each other, the base 5 and the frames 6 and 7 are prevented from slipping laterally. In addition to this, in the embodiment, connecting means are provided to improve the integrity between the rear frames 7 and the integrity between the frames 6 and 7 and the base 5 . This point will be explained.

First, regarding the connection relationship between the left and right rear frames 7, for example, as shown in FIG. The other rear base 7a is formed with laterally open engagement holes 23 into which the engagement projections 22 are tightly fitted. The integration of the left and right rear frames 7 can be improved by the fitting between the engaging projections 22 and the engaging holes 23 . Although the engaging projection 22 and the engaging hole 23 are substantially triangular in side view, various shapes such as a square and a circle can be adopted.

Next, regarding the relationship between the rear frame 7 and the base 5, for example, as shown in FIG. A side engaging groove 25 to be fitted with a side boss 24 is formed in the front portion of the portion 7a overlapping the outer surface of the base 5. As shown in FIG. As a result, the integrity between the rear substrate 7a and the base 5 is improved, and the strength can be increased.

As a means for improving the unity between the base 5 and the rear frame 7, for example, as shown in FIG. While protruding, the rear base 7a of the rear frame 7 is formed with an engaging stepped portion 27 into which the engaging piece 26 is fitted from above. The engaging piece 26 and the engaging stepped portion 27 also function as positioning means for accurately defining the lateral positions of the front frame 6 and the rear frame 7 .

(4) Seat Attachment Structure Next, the attachment structure of the seat 1 to the front frame 6 will be described mainly with reference to FIGS. For example, as shown in FIG. 7(A), the upper end of the front frame 6 serves as a longitudinal receiving portion 29, and the seat 1 is tilted forward and backward through the longitudinal seat tilting unit 30 on the receiving portion 29. installed possible. The receiving portion 29 protrudes from the upper end of the front frame 6 on both front and rear sides.

For example, as clearly shown in FIG. 6, the tilting unit 30 for the seat includes, as main members, upper and lower brackets 31 and 32 which are longitudinally elongated, and a pair of front and rear elastic bodies 33 arranged between them. The lower bracket 32 has left and right side plates 32a and has a U-shaped configuration with an upward opening when viewed from the front. ing.

As shown in FIG. 3A, the seat 1 has a structure in which a cushion material 34a is superimposed on a seat inner shell 34 made of synthetic resin. A recessed groove 35 is formed in the left and right side portions of the shell 34 and opens downward in the front-rear longitudinal direction.

The upper bracket 31 also has a downward-opening U-shape with left and right side plates 31a. As can be seen from FIG. 7B, the lower bracket 32 is covered with the upper bracket 31. The upper bracket 31 and the recessed groove 35 are approximately twice as long as the lower bracket 32, and protrude slightly in front of the lower bracket 32 and protrude greatly behind it.

Specifically, the upper bracket 31 protrudes behind the upper bracket 31 by approximately the same dimension as the lower bracket 32 . The reason why the upper bracket 31 is much longer than the lower bracket 32 is to ensure the necessary support strength, considering that the seat inner shell 34 is made of resin. The rear half portions of the upper bracket 31 and the concave groove 35 are narrowed because the required strength can be secured even if they are narrowed.

Although the front frame 6 is a molded resin product (it may be an aluminum die-cast product), the required thickness can be ensured, so the receiving portion 29 does not need to be formed long like the upper bracket 31. Strength can be secured. When the upper bracket 31 protrudes largely behind the receiving portion 29 (overhangs) as in the embodiment, the receiving portion 29 can be fitted into the recessed groove 35 as deeply as possible while allowing the seat 1 to tilt backward. .

As shown in FIG. 8A, the upper bracket 31 is fixed to the seat inner shell 34 with front and rear upper screws 36, while the lower bracket 32 receives the front frame 6 with lower screws 37 located at the front. It is fixed to the part 29 . For example, as shown in FIG. 8A, the seat inner shell 34 is provided with a T-shaped nut 36a into which an upper screw 36 is screwed. Therefore, even if the seat inner shell 34 is made of resin, high fastening strength can be ensured.

As in the embodiment, the burring portion 41 at the rear portion of the lower bracket 32 serves both as fastening means for the receiving portion 29 and positioning means for the elastic body 33, so that the structure can be simplified accordingly.

Further, as shown in FIG. 7(B), an engaging piece 32b is formed at the rear end of the lower bracket 32, and this engaging piece 32b is attached to the rear end of the receiving portion 29 as shown in FIG. 8(A). It is inserted from the front into a positioning groove 38 formed in the part. Therefore, the rear end of the lower bracket 32 is held by the positioning groove 38 so as not to move up and down.

More specifically, although it is possible to fix the rear portion of the lower bracket 32 with screws, since the front frame 6 exists in an inclined position below the rear portion of the lower bracket 32, screws with a screwdriver tool (wrench) cannot be used. is extremely troublesome to rotate, in this embodiment, the rear portion of the lower bracket 32 is held so as not to move upward without being fastened with a screw. There is no need to do so, and the work efficiency can be improved accordingly.

The upper bracket 31 and the lower bracket 32 are connected to each other by pivot pins 39 extending in the left-right direction so as to be relatively rotatable. The pivot pin 39 connects side plates 31a and 32a of the upper and lower brackets 31 and 32 via bushes 39a.

On both front and rear sides of the pivot pin 39, square block-shaped elastic bodies 33 made of resin-based rubber (cellast) are arranged. As clearly shown in FIG. 8B, a space is provided between the left and right side surfaces of the elastic body 33 and the side plates 32a of the lower bracket 32. As shown in FIG. Therefore, even if the elastic body 33 is compressed and deformed, the deformation is not restricted by the side plate 32a of the lower bracket 32, and the elastic body 33 is freely deformed in the horizontal direction. Moreover, as shown in FIG. 8(A), there are spaces on both front and rear sides of the elastic body 33 . Therefore, the elastic body 33 can be freely deformed also in the front-rear direction. As a result, the elastic body 33 expands and deforms freely over the entire circumference.

As shown in FIG. 6, the elastic member 33 has non-penetrating recessed positioning holes 40 that are open to the upper and lower surfaces. As shown in FIG. A burring portion 41 to be fitted in the positioning hole 40 is formed in the . Therefore, the elastic body 33 is held so as not to be displaced in any of the front, rear, left, and right directions even when its circumference is not restricted by other members. The lower screw 37 is screwed into the front burring portion 41 of the lower bracket 32 . The burring portion 41 corresponds to the positioning projection described in the claims.

In FIG. 8(B), a one-dot chain line indicates the free length of the elastic body 33 . Therefore, the elastic body 33 is set in the seat tilting unit 30 in a pre-compressed state (pretensioned state). Therefore, the user's load can be properly supported without causing the phenomenon of the user to tilt backwards at the same time as the user sits down.

In addition, the strength (elastic restoring force) of the front and rear elastic bodies 33 is set to be the same. This is because if the strengths of the front and rear elastic bodies 44 are different, the seat 1 cannot be held in the reference posture when the person is not seated. When the seat 1 tilts backward, the front elastic body 33 acts to promote the rearward tilt of the seat 1, and when the seat 1 tilts forward, the rear elastic body 33 promotes the forward tilt of the seat 1. acts like In FIG. 8A, the movements of the seat 1 tilting backward and tilting forward are indicated by dashed lines.

When the chair is normally used, the center of gravity of the seated person is behind the pivot pin 39, so the seat 1 tilts backward against the elastic body 33 behind. This provides cushioning properties. The degree of backward tilt is proportional to the weight of the seated person.

For example, as shown in FIG. 6, the inner bottom surface of the receiving portion 29 is formed with longitudinal ribs. One side plate 31a of the upper bracket 31 contacts the stopper rib 29b, thereby restricting the maximum tilting angle of the seat 1. As shown in FIG. The maximum rearward inclination angle of the seat 1 can also be regulated by bringing the upper plate of the upper bracket 31 into contact with the side plate 32 a of the lower bracket 32 .

When a person leans on the front end of the seat 1 or stretches his or her body while leaning against the backrest 2, and the pressing force on the seat 1 acts on a portion in front of the pivot pin 39, the seat 1 is It leans forward against the front elastic body 33 . Thereby, comfort can be improved. In the drawing, the front and rear elastic bodies 33 are drawn to have the same size, but the front elastic body 33 is set to have a smaller diameter than the rear elastic body 33 so that the seat 1 can tilt forward with a light force. It is also possible to

As can be understood from FIG. 7A, the inner surface of the groove 35 in the seat inner shell 34 is formed with an auxiliary recess 35a for allowing the end of the pivot pin 39 to escape. Therefore, the upper bracket 31 can be tightly fitted into the recessed groove 35, and the posture of the seat tilting unit 30 can be accurately aligned. As a result, the pivot pins 39 of the right and left seat tilting units 30 can be arranged concentrically and accurately, and the seat 1 can be smoothly tilted without twisting.

Further, the inner end of the pivot pin 39 is held by the concave groove 35 so as not to come off. On the other hand, as shown in FIG. 6, the outer end of the pivot pin 39 is fitted in a recess 29a formed in the outer plate of the receiving portion 29 and is held by the outer plate of the receiving portion 29 so as not to come off. there is Therefore, a retaining means such as a snap ring is not required, and as a result, the cost can be suppressed and the assembling workability is also excellent.

The seat tilting unit 30 is assembled in advance. That is, the upper and lower brackets 31 and 32 are connected by the pivot pin 39 while the two elastic bodies 33 are pressed. In assembling the chair, first, the seat tilting unit 30 is fixed to the seat inner shell 34 with the upper screws 36, then the seat tilting unit 30 is fitted into the receiving portion 29 of the front frame 6, and the lower screws 37 are attached. should be fixed with .

(5) Others Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, the object of application of the present invention is not limited to swivel chairs, but can also be applied to fixed-legged chairs that are frequently used for conferences and the like. Also, although not shown, it is also possible to dispose only one of the front frame and the rear frame at the right and left intermediate portions. Alternatively, either one of the front frame and the rear frame can be configured with two left and right, and the other can be configured with only one.

A compression coil spring may be used as the elastic body, or a rubber elastic body and a spring may be used together. Forming the upper bracket integrally with the seat inner shell and forming the lower bracket integrally with the seat support such as the front frame can be optionally selected. When the upper and lower brackets are formed in a U-shaped gutter, the upper bracket may be surrounded by the lower bracket.

Furthermore, the upper and lower brackets can be set in any shape. For example, the upper bracket can be formed in an inverted L shape, the lower bracket can be formed in an L shape, or the upper and lower brackets can be formed in a semicircular gutter shape.

The structure of the seat and backrest can also be set arbitrarily. For example, a structure in which a mesh is stretched on the frame can also be adopted. The base can be provided integrally with the front frame or the rear frame, or the front frame, the rear frame, and the base can be manufactured as an integral product. Alternatively, the left and right front frames can be configured separately, or the bases of the front and rear frames can be covered with covers.

The present invention can be embodied in a chair. Therefore, it can be used industrially.

REFERENCE SIGNS LIST 1 seat 2 backrest 4 leg support 5 base 6 front frame as an example of a seat support 7 rear frame 29 receiving portion 30 seat tilting unit 31 upper bracket 32 lower bracket 33 elastic body 34 seat inner shell 35 concave groove 39 pivot pin
40 positioning hole
41 Burring part (positioning projection)

Claims (3)

A seat and a backrest which are separated from each other are provided, and the seat is attached to a seat support disposed below the seat, and a laterally long pivot pin is attached to the seat support so as to deform the rubber elastic body and at least tilt backward. The configuration is connected by
The elastic body is sandwiched between an upper bracket provided on the lower surface of the seat and a lower bracket provided on the upper surface of the seat support in an unrestrained state from the outer circumference ,
The elastic body is formed with a positioning hole that is open on the upper surface, the lower surface, or both upper and lower surfaces so as not to penetrate vertically,
One or both of the upper and lower brackets is provided with a positioning projection that enters the positioning hole and holds the elastic body so that it does not move laterally.
Chair. The seat support is composed of a front frame extending from a base provided at the upper end of the leg support toward the front portion of the seat in an inclined posture when viewed from the side, and the lower bracket is provided at the upper end of the front frame. on the other hand,
The seat has a structure in which a seat cushion material is superimposed on the upper surface of an inner seat shell made of synthetic resin, and the upper bracket made of sheet metal is fixed to the lower surface of the inner seat shell,
The upper bracket and the lower bracket are connected by the laterally long pivot pins, and the elastic body is arranged at least behind the pivot pins.
A chair as claimed in claim 1. A recessed groove into which the upper bracket is fitted is formed in the lower surface of the seat inner shell, and the pivot pin is held by the recessed groove so as not to come off.
A chair according to claim 2 .

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