JP7208734B2 - Chair - Google Patents

Description

The present invention relates to a chair with a backrest.

There are various types of chairs, and there are various ways of classifying them. Chairs with backrests are roughly divided into those with backrests and those without backrests. Chairs with backrests are rocking types in which the backrests tilt backwards against elastic means, and chairs with bending deformation of members. Aside from tilting backwards, they are basically divided into those that do not tilt backwards.

Furthermore, when looking at leg devices, there are revolving chairs that are equipped with gas cylinder leg supports and the height of the seat can be adjusted, and those with fixed leg devices that cannot be adjusted in height. In the case of having different leg supports, the base is fixed to the upper end of the leg supports, and the seat and backrest are attached to the base.

A swivel chair generally has a backrest of a locking type. For example, as disclosed in Patent Document 1, a backrest is attached to a backrest by connecting a backrest to a base so as to be tiltable backward. The seat is often tilted backward or backward in conjunction with the backward tilting motion of the backrest.

JP 2012-40110 A

To provide a chair in which a backrest is attached to a back support rod (back strut) erected from a base arranged under a seat, and for example, when the backrest is tilted backward, the backrest is simply structured without tilting the back support rod backward. It is conceivable that there may be a desire to arrange so as to tilt backward. In other words, there may be a desire to simplify the structure of a chair with a base as much as possible.

In this case, the backrest should be provided with a fixed rear frame that does not tilt backwards, and the backrest should be attached to the rear frame.The seat should be provided with a front frame on the base, and the seat attached to the front frame. It can be said that it is good. It is conceivable to integrate the rear frame and front frame into the base, but in this case, the overall size will be large, so the mold equipment will be extremely large in manufacturing by aluminum die casting or resin injection molding. Therefore, it is not realistic.

When fixing the rear frame for attaching the backrest and the front frame for attaching the seat to the base, various forms can be considered for both the front frame and the rear frame. should be considered. However, there is no conventional technology that meets such a demand.

The present invention has been made based on this situation, and provides a structure that considers strength and aesthetics in a chair that has a backrest attached to a fixed rear frame and a seat attached to a fixed front frame. This is what we are trying to achieve. Moreover, although the present invention discloses many novel configurations, these can be claimed as independent inventions.

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 ; a base that is arranged below the seat and is supported by a leg device; a front frame that is arranged above the base and to which the seat is attached ; a rear frame disposed above the base and to which the backrest is attached ,
In a configuration in which the front frame and the rear frame are separate bodies, the seat is attached only to the front frame, and the backrest is attached only to the rear frame ,
Both the front frame and the rear frame are integrally formed with bases that overlap the bases from above, and the bases and the bases are fitted to each other to hold the bases horizontally so as not to be displaced. A locating means is formed for locating the base and bolting the bases to the base."
It is configured.

In this case, one set of positioning means may be provided, or a plurality of sets may be provided. For example, it is possible to separately provide a device for preventing longitudinal displacement and a device for preventing lateral displacement. A blocking function may be provided.

The invention of claim 2 is a specific example of the positioning means in claim 1. In this invention,
"A concave portion is formed in the base as the positioning means, a convex portion that fits into the concave portion is formed in the base portions of the front frame and the rear frame, and the base portion is positioned between the concave portion and the convex portion. is fixed to the base with said bolt."
It is configured.

The invention of claim 3 is a preferred development example of claim 1 or 2,
"The rear frame is separated into a left rear frame having a left back support positioned on the left side of the backrest and a right rear frame having a right back support positioned on the right side of the backrest. The bases are integrally provided on the rear frame, and the left and right bases are held so as not to be displaced forward and backward by fitting bosses that protrude sideways into boss holes that open sideways.
It is configured.

Furthermore, as a development example of claim 3, in claim 4,
“At the base of the left and right rear frames, a side wall overlapping the side surface of the base and a rear wall overlapping the rear surface of the base are formed, and the left and right side walls are opened toward the side surface of the base. Side engagement grooves are formed on the left and right sides of the base, and side projections that fit into the side engagement grooves are provided on the left and right side surfaces of the base.
It is configured.

The invention of claim 5 is applied to a swivel chair. That is, in any one of claims 1 to 4,
"The base is fixed to the upper end of the leg strut consisting of a gas cylinder, and an elevating lever for unlocking the gas cylinder and adjusting the height is attached to the base so that it does not protrude above the base. and the upper surface of the base is entirely covered by the base of the rear frame or the base of the front frame or both."
It is configured.

According to the invention of claim 5, in any one of claims 3 to 5,
"While the bases of the left and right rear frames are fixed to the bases by bolts that pass through the bases from above,
There are a pair of left and right front frames, and both are integrally connected to a common base, and the base of the front frame covers the bolts that fix the rear frame from above.”
It is configured.

In the present invention, since the base of the rear frame and the base of the front frame are overlapped and fixed on the upper surface of the base, the base of the rear frame and the base of the front frame can function as a cover that covers the base from above. Therefore, a simple form can be realized. Further, since the base portion and the base are held by the positioning means so as not to be displaced in the horizontal direction, high fixing strength can be ensured.

In addition, since the seat and backrest are attached to the fixed frame, the front frame and the rear frame can be made as slim as possible while ensuring necessary support strength. In this respect as well, it can be said that the product value can be improved by improving the appearance.

As the positioning means, for example, it is possible to form a projection on the base and form a recess on the base of the frame. , there is a problem that the base of the frame must be thickened. On the other hand, according to claim 2, since the base of the frame is formed with a convex portion, it is not necessary to make the base of the frame excessively thick. Therefore, it can contribute to weight reduction and compactness.

If the left and right rear frames are each provided with a back strut, the size as a whole becomes considerably large. Therefore, even if it is possible to integrally manufacture the whole by aluminum die-casting or resin molding, the mold apparatus for manufacturing is considerably enlarged, and the manufacturing cost is considerably increased.

On the other hand, if the rear frame is separated into the left and right sides as in claim 3, the size of the rear frame will be considerably reduced even if the rear frame has a structure with a back strut, so the mold device will not be excessively large. Absent. Therefore, it is possible to prevent the mold device from becoming excessively large and to reduce the manufacturing labor. Therefore, it is realistic.

And if the rear frame is separated on the left and right, there is a risk of rattling. When the left and right rear frames are positioned by fitting the bosses into the boss holes as in claim 3, the left and right rear frames are integrated. it becomes possible to

When a seated person leans against the backrest, a large moment acts on the rear frame. Therefore, the rear frame must be held in a state of firmly supporting the load that is to be tilted backward. In this regard, in the configuration of claim 4, first, the rear frame has a wall facing downward, thereby significantly improving rigidity. Extremely high resistance to backward tilting of the frame is exhibited.

Therefore, according to claim 4, the attachment strength of the rear frame can be significantly improved. In addition, since the outer periphery of the base is covered with the wall of the rear frame, the base is prevented from being exposed, which contributes to improving the appearance.

If the leg struts consist of gas cylinders, a lift lever is required to unlock and adjust the seat height. In this case, if the lifting lever is provided on the upper surface of the base, the lifting lever will be visible, which may reduce the simplicity and reduce the commercial value. In this regard, in the configuration of claim 5, the upper surface of the base is covered with the rear frame or the base of the base, so that the lifting lever is not exposed above the base and visible. Therefore, the simplicity can be maintained and the commercial value can be improved.

In particular, when the lift lever extends laterally from below the base as in the embodiment, the entire outer circumference of the base can be surrounded by the frame wall without interruption, thereby further contributing to the improvement of the appearance.

When the rear frame is separated into the left and right sides, the boundary line (mating surface) between the left and right rear frames is exposed, but from the viewpoint of aesthetics, it is preferable to minimize the exposure of the boundary line. Moreover, from the point of view of aesthetics, it is preferable to minimize the exposure of bolts and bolt insertion holes for fixing the rear frame and the front frame.

In this regard, in the configuration of claim 6, since the bolts for fixing the rear frame are hidden in one base portion of the front frame, exposure of the bolts and the bolt insertion holes can be suppressed. In addition, since one base portion of the front frame spreads rearward, exposure of the boundary line between the left and right rear frames can be suppressed. As a result, it is possible to enhance simplicity and further contribute to improvement of aesthetic appearance.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the chair which concerns on embodiment, (A) is a perspective view in the state which provided the armrest, (B) is a perspective view in the state in which the armrest is not provided, (C) is a back perspective view, (D) is a perspective view of a state in which the seat is separated; (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; (A) is an exploded perspective view of a main part, and (B) is a lower perspective view of a base. (A) is a perspective view from below with the base omitted, (B) is a perspective view of the base, and (C) is a perspective view of the lifting lever. 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. Fig. 10 is a perspective view showing the second embodiment, wherein (A) is an isolated perspective view seen from the rear with the frame turned over, and (B) is an exploded perspective view of the rear frame; FIG. 11 is an exploded perspective view of the second embodiment, viewed from the front side with the frame turned over.

(1). Overview Next, embodiments of the present invention will be described. The present invention 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 bases 5 (see FIG. 3) are attached to the upper ends 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 a front frame 6 and left and right rear frames 7 are fixed to the base 5 . Left and right corners are formed on the front frame 6, and the seat 1 is attached to the left and right corners so as to be tiltable back and forth. The rear frame 7 has a back support 7b located on the side of the backrest 2, and the backrest 2 is connected to the back support 7b so as to be tiltable backward.

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. A cover 7c is attached to the back support 7b of the rear frame 7 when the armrest 8 is not attached. For example, as shown in FIG. 3B, an elevating 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 near 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. As shown in FIG. 2(D), when viewed from the front, the back support 7b is tilted upward and spreads outward up to approximately the height of the seat 1, and the back support 7b is in the range above the seat 1. almost upright.

The back support 7b 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 pivot point (rotation center) O1 (see FIG. 2B) 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 front frame 6 is an aluminum die-cast product or a resin-molded product, and a front base portion 6a having a substantially square shape (horizontally long rectangle) in a plan view is integrally continuous. On the other hand, the left and right rear frames 7 are also aluminum die-cast products or resin-molded products, and are separated from each other. The left and right rear base portions 7a overlap so as to be continuous in the left and right direction, and the left and right rear base portions 7a and the front base portion 6a overlap in the front-rear direction.

For example, as clearly shown in FIG. 4, the rear base portion 7a of the rear frame 7 has a rear wall 7d overlapping the rear surface of the base 5 and side walls 7e overlapping the outer surface of the base 5. As shown in FIG. On the other hand, the front base portion 6a also includes a front wall 6b overlapping the front surface of the base 5 and side walls 6c overlapping the outer surface of the base 5. As shown in FIG.

Therefore, the front base portion 6a and the left and right rear base portions 7a are overlapped as if forming one member as a whole, and the base 5 is completely covered from above and from the outer periphery by these three members. Therefore, the two corners of the front frame 6 and the two rear frames 7 have an appearance as if they stand diagonally from the bases 6a, 7a, which are substantially rectangular in plan view, in an inclined posture. is not visible unless the chair is turned over.

(2) Design Effect As described above, the front frame 6 and the rear frame 7 are visible, and the bases 6a and 7a of both are also visible especially in a rear view. 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 are converged toward the base 5 from the diagonal direction of the seat 1, the supporting function of the seat 1 and the backrest 2 is ensured, while the appearance is eliminated. It can be said that it is an excellent design in terms of both function and aesthetics.

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 back support 7b overlaps the outer surface of the lower end portion of the backrest 2 in substantially the same posture, the uniformity of the posture appears and a refreshing aesthetic effect is exhibited.

Although the tilting structure of the seat 1 will be described later, the pivot point O2 (see FIG. 2B) is displaced toward the front side of the seat 1. As shown in FIG. 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 .

(3) Frame Attachment Structure Next, a first embodiment of 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, and has a horizontally elongated block shape. A central hole 10 into which the upper end of the leg support 4 is fitted is provided in the central portion. A pair of left and right front concave portions 11 are formed in the front portion of the upper surface of the base 5 as part of the positioning means described in the claims, and a rear concave portion 12 is formed in the rear portion. The recesses 11 and 12 are provided with tapped holes. 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. Further, the front recess 11 is cut open in the front surface of the base 5, and the rear recess 12 is open upward, but the rear recess 12 can also be formed in a cut-open manner. 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 that tightly fits into the front concave portion 11 of the base 5 is formed on the lower surface of the front base portion 6 a of the front frame 6 . 5 with a front bolt 14. Similarly, the rear base portion 7a of the rear frame 7 is formed with rear projections 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 portion 6a and the rear base portion 7a.

The rear base portion 7a slightly overlaps 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 portion 7a is formed in an L shape in plan view, and a rear convex portion 15 is formed at an inner corner portion thereof.

On the other hand, the front base portion 6a protrudes greatly rearward so as to cover the space surrounded by the left and right rear frames 7. As shown in FIG. That is, it has an eave-like portion, and the rear convex portion 15 is covered with the eave-like portion of the base portion 6 a of the front frame 6 . Therefore, the rear bolts 16 cannot be visually recognized from the outside, and the heads of the front bolts 14 are also hardly visible because they are inside the mounting holes 18 .

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 frames 7 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. A receiving piece 20 on which the rear end portion of the front base portion 6a rests is formed on the rear base portion 7a.

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 provided 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. A lateral boss hole 23 into which the lateral boss portion 22 is tightly fitted is formed in the rear base portion 7a. The integration of the left and right rear frames 7 can be improved by fitting the lateral boss portions 22 and the lateral boss holes 23 . The lateral boss portion 22 and the lateral boss hole 23 are substantially triangular in side view, but various shapes such as a square and a circle can be adopted (variations are mentioned in the second embodiment).

Next, regarding the relationship between the rear frame 7 and the base 5, for example, as shown in FIG. A side engaging groove 25 that engages with a side protrusion 24 is formed in the front portion of the portion of the base portion 7a that overlaps the outer surface of the base 5 . Thereby, the integration between the rear base portion 7a and the base 5 is improved.

As a means for improving the unity between the base 5 and the rear frame 7, for example, as shown in FIG. On the other hand, the rear base portion 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 and as means for preventing the front frame 6 from warping.

(4) Mounting structure of lifting lever As shown in FIG. and a vertical portion 9c extending downward from the base end of the support shaft portion 9a. A horizontal finger hook portion extends laterally from the lower end of the vertical portion 9c. there is

The pressing portion 9b is fitted into a cut-out groove 30 opened upward and formed in a boss body tilting the center hole 10 backward. The vertical portion 9c is fitted in a hole 31 that vertically penetrates the base 5. When the finger hook portion of the lifting lever 9 is pulled upward, the lifting lever 9 rotates about the shaft portion 9a. , the push valve 4a of the leg support 4 is pushed down by the pushing portion 9b. As a result, the gas cylinder, which is the leg strut 4, is unlocked, and the height of the seat 1 can be adjusted.

In this embodiment, as shown in FIG. 7B, the bearing groove 29 is formed in an auxiliary recess 32 recessed downward, and the support shaft 9a of the lift lever 9 is located on the upper surface of the base 5. 7(A), on the lower surface of the base portion 6a of the front frame 6, a shaft support projection 33 that fits into the auxiliary recess 32 from above is directed downward. The support shaft portion 9a of the lifting lever 9 is held by the shaft support projection 33 so as not to move upward.

Therefore, the lift lever 9 is rotatably held by the front frame 6, and a bearing member for holding the support shaft portion 9a from above is not required. Therefore, the structure can be simplified. In the embodiment, since the auxiliary recess 32 is covered with the base 6a of the front frame 6, the pivotal support projection 33 is formed in the base 6a of the front frame 6. If it is covered, the pivotal support projection 33 is formed on the base portion 7a of the rear frame 7. As shown in FIG.

As clearly shown in FIG. 7(B), the auxiliary recess 32 is positioned behind one front recess 11 . Therefore, the support shaft portion 9a of the lift lever 9 is located behind the base 5, and a pressing portion 9b is formed at the rear end of the support shaft portion 9a. Therefore, the pressing portion 9b is inclined with respect to the front-rear longitudinal line and the left-right lateral line in plan view.

When the lifting lever 9 is exposed below the base 5 and extends laterally as in the present embodiment, the periphery of the base 5 can be surrounded by the bases 6a and 7a of both the frames 6 and 7 without gaps, resulting in a beautiful appearance. In addition, the fixing strength of both frames 6 and 7 can be improved.

(5) 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 is a receiving portion 35 that is longitudinally long. installed possible. The receiving portion 35 protrudes from the upper end of the front frame 6 to both the front and rear sides.

For example, as clearly shown in FIG. 7, the tilting unit 36 for the seat mainly includes upper and lower brackets 37 and 38 extending in the front-rear direction and a pair of elastic members 39 arranged in the front-rear direction. The lower bracket 38 has left and right side plates 38a and has a U-shaped configuration with an upward opening when viewed from the front. ing.

As shown in FIG. 3(A), the seat 1 has a structure in which a cushion material 40a is superimposed on a seat inner shell 40 made of synthetic resin. A recessed groove 41 is formed in the left and right side portions of the shell 40 and opens downward in the front-rear longitudinal direction.

The upper bracket 37 also has a downward-opening U-shape with left and right side plates 37a. As can be seen from FIG. 9B, the lower bracket 38 is covered with the upper bracket 37. The upper bracket 37 and the recessed groove 41 are approximately twice as long as the front-to-rear length of the lower bracket 38, and protrude a little in front of the lower bracket 38 and protrude greatly in the rear.

Specifically, the upper bracket 37 protrudes behind the upper bracket 37 by approximately the same dimension as the lower bracket 38 . The reason why the upper bracket 37 is much longer than the lower bracket 38 is to ensure necessary support strength considering that the seat inner shell 40 is made of resin. The rear half portions of the upper bracket 37 and the recessed groove 41 are narrowed because the necessary strength can be secured even if they are narrowed.

Although the front frame 6 is a molded product of resin (it may be an aluminum die-cast product), the receiving portion 35 does not have to be formed long like the upper bracket 37, but the required strength can be ensured. When the upper bracket 37 protrudes largely behind the receiving portion 35 (overhangs) as in the embodiment, the receiving portion 35 can be fitted into the recessed groove 41 as deeply as possible while allowing the seat 1 to tilt backward. At the same time, the support strength of the seat 1 can be significantly improved.

As shown in FIG. 9A, the upper bracket 37 is fixed to the seat inner shell 34 with front and rear upper screws, while the lower bracket 33 is attached to the receiving portion 35 of the front frame 6 with lower screws positioned at the front. is fixed to As shown in FIG. 8, a T-shaped nut 42a into which an upper screw (not shown) is screwed is arranged on the upper surface of the seat inner shell 34. As shown in FIG. 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 47 at the rear portion of the lower bracket 38 serves both as fastening means for the receiving portion 35 and positioning means for the elastic body 39, so that the structure can be simplified accordingly.

Further, as shown in FIG. 9(B), an engaging piece 38b is formed at the rear end of the lower bracket 38, while a positioning groove is formed at the rear end of the receiving portion 35 as shown in FIG. 9(A). 44 is formed, and the engaging piece 38b is inserted into the positioning groove 44 from the front. Therefore, the rear end of the lower bracket 38 is held by the positioning groove 44 so as not to move up and down. It is

The upper bracket 37 and the lower bracket 38 are connected to each other by pivot pins 45 extending in the left and right directions so as to be relatively rotatable. The pivot pin 45 connects side plates 37a and 38a of the upper and lower brackets 37 and 38 via bushings 39a. On both front and rear sides of the pivot pin 45, square block-like elastic bodies 33 made of resin rubber (cellast) are arranged.

As shown in FIG. 8, positioning holes 46 are formed in the upper and lower surfaces of the elastic body 39, while the upper bracket 37 and the lower bracket 38 are provided with a hole as shown in FIG. 8 (see also FIG. 9B). , a burring portion 47 that fits into the positioning hole 46 is formed. Therefore, the elastic body 39 is held so as not to slip in any direction, front, rear, left, or right, even if its periphery is not restricted by other members. A lower screw (not shown) is screwed into the burring portion 47 of the upper and lower brackets 37 and 38 . The elastic body 33 is set in the seat tilting unit 36 in a pre-compressed state (pretensioned state).

As can be understood from FIG. 9A, the inner surface of the groove 41 in the seat inner shell 40 is formed with an auxiliary recess 41a for allowing the end of the pivot pin 45 to escape. Therefore, the upper bracket 37 can be tightly fitted into the recessed groove 41, and the posture of the seat tilting unit 36 can be accurately aligned.

(6).Second embodiment.
Next, a second embodiment shown in FIGS. 10 and 11 will be described. This embodiment is another example of the mounting structure of the base 5 and the front frame 6 and rear frame 7 . The second embodiment does not differ greatly in basic structure from the first embodiment. Therefore, elements having the same functions as those of the second embodiment are given the same reference numerals as those of the first embodiment. 10A and 11, the base 5 is shown on a scale larger than the front frame 6 and the rear frame 7. As shown in FIG.

This embodiment differs from the first embodiment in that although it has the same elements as in the first embodiment, it has a different shape, and in that it has positioning means that is not provided in the first embodiment. There is First, as a difference in shape, as shown in FIG. 10, there are lateral boss portions 22 and lateral boss holes 23 for connecting the left and right rear frames 7 .

That is, in this embodiment, the lateral boss portion 22 has a U-shape when viewed from the side, while the lateral boss hole 23 has a trapezoidal shape. Although the front-rear width of the lateral boss portion 22 is considerably smaller than the front-rear width of the lateral boss hole 23, the lateral boss portion 22 and the lateral boss hole 23 are mainly provided so that the vertical heights of the left and right rear frames 7 are aligned. Therefore, even in such a form, the purpose can be sufficiently achieved.

In this embodiment, as means for tightly fitting the left and right rear frames 7, a stepped portion 23a is formed along the entire periphery of the opening edge of the lateral boss hole 23, while the lateral boss portion 22 is provided on the rear frame. 7 is formed with a ridge 22a that fits into the stepped portion 23a. Further, the rear frame 7 provided with the lateral boss portion 22 is formed with a thinning hole 22b for making the thickness as uniform as possible.

In the first embodiment, the side protrusions 24 are formed in a circular shape, but in this embodiment, the protrusions 24 are again formed in an oval shape, as shown in FIG. Therefore, the adhesion between the rear frame 7 and the side engaging grooves 25 is improved, and the integration between the rear frame 7 and the base 5 is also enhanced.

Next, the front concave portion 11 and the front convex portion 13 will be described. The front concave portion 11 is formed in a quadrangular shape in plan view as in the first embodiment, but as shown in FIG. It is formed in a U shape when viewed from the bottom.

As for the rear concave portion 12 provided on the base 5 and the rear convex portion 15 provided on the rear frame 7, as shown in FIG. Accordingly, the rear projection 15 is integrally connected to the rear base 7a. Therefore, the strength of the rear protrusion 15 is increased.

Further, the rear concave portion 12 and the rear convex portion 15 have an inverted trapezoidal shape when viewed from the rear and from the front. Therefore, when tightened by the rear bolt 16, the rear concave portion 12 and the rear convex portion 15 are brought into tight contact. As a result, it is possible to improve the positioning function between the rear frame 7 and the base 5 (the function of preventing displacement in the left-right direction), and also improve the fastening strength by eliminating the gap.

In this embodiment, as a positioning means not provided in the first embodiment, a center engagement hole 44 is formed in the front part of the base 5 and in the left and right intermediate parts. A center projection 45 that fits into the center engaging hole 44 is formed. The center engaging hole 44 and the center projection 45 are tapered to expand upward.

Therefore, when the front frame 6 is fastened to the base 5, the center engaging hole 44 and the center projection 45 are brought into close contact with each other, exhibiting a high positioning function. 6 and the base 5 are held so as not to be displaced in any of the front, rear, left, and right directions.).

Further, as a new positioning means for the rear frame 7 and the base 5, as shown in FIG. On the other hand, the inner end of the rear frame 7 is formed with a hook-shaped rear inside engaging portion 48 that fits into the rear inside recess 47 from above. The rear inside engagement portions 48 of the left and right rear frames 7 overlap on the left and right. In the rear frame 7 , the rear inside engaging portion 48 and the rear convex portion 15 are connected via a flange-shaped portion 7 a ′ of the rear base portion 7 a that overlaps the upper surface of the base 5 .

The rear plate 49 of the base 5 is formed with a recess 50 in which the rear inside engaging portion 48 is fitted, which is cut open upward. In this respect as well, the lateral shift between the rear frame 7 and the base 5 is regulated. Further, as shown in FIG. 10(A), a stepped portion 48a is formed on the upper surface of the rear inside engaging portion 48, while a rear inside portion 48a is formed on the rear edge of the Floton base portion 6a constituting the front frame 6. As shown in FIG. A overlapping portion 51 is formed to overlap the stepped portion 48 a of the engaging portion 48 . This also enhances the integration between the front frame 6 and the rear frame 7 .

In the first embodiment, as shown in FIG. 4, the engagement piece 26 is provided at the rear end of the front base portion 6a and the engagement stepped portion 27 is formed at the front end of the rear base portion 7a. The functions of the piece 26 and the engaging stepped portion 27 are performed by the stepped portion 48a of the rear inside engaging portion 48 and the overlapping portion 51 of the front base portion 6a. As shown in both FIGS. 10A and 11, in the present embodiment, a recess 52 concentric with the support leg 4 is formed in the lower surface of the front base portion 6a that constitutes the front frame 6. As shown in FIG.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, as a means for positioning the front frame, the rear frame, and the base, the front frame and the rear frame are integrally formed, and the base portion where the two are connected is formed into a frame shape with a downward opening, and the base is completely covered with the base portion. It is also possible to say Further, the application of the present invention is not limited to swivel chairs, but can also be applied to fixed-legged chairs whose seats do not rotate or move up and down.

Although the rear frame is separated left and right in the embodiment, it is also possible to manufacture the rear frame as a single piece. In this case, the means for positioning the left and right rear frames 7 as in the embodiment is not required. As the positioning means, for example, concentric holes may be provided in the base and the front frame or the rear frame 7 (or both), and positioning pins may be fitted into the upper and lower holes.

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

1 seat 2 backrest 4 leg support 5 base 6 front frame 6a front base (base of front frame)
6b, 6c wall 7 rear frame 7a rear base (base of rear frame)
7b Back post 7d Rear wall 7e Side wall 9 Elevating lever 11 Front concave portion constituting positioning means 12 Rear concave portion constituting positioning means 13 Front convex portions constituting positioning means 14, 16 Bolt 15 Rear convex portion constituting positioning means 22 boss portion 23 boss hole 24 side projection 25 side engagement groove

Claims (6)

a seat and a backrest that are separated from each other ; a base arranged below the seat and supported by a leg device; a front frame arranged above the base and to which the seat is attached; and a rear frame to which the backrest is attached, located above the
The front frame and the rear frame are separate bodies, the seat is attached only to the front frame, and the backrest is attached only to the rear frame ,
Both the front frame and the rear frame are integrally formed with bases that overlap the bases from above, and the bases and the bases are fitted to each other to hold the bases horizontally so as not to be displaced. positioning means are formed to hold the two bases together, and bolt the bases to the base;
Chair. A concave portion is formed in the base as the positioning means, and a convex portion that fits into the concave portion is formed in the base portions of the front frame and the rear frame. fixed to the base by said bolt,
A chair as claimed in claim 1. The rear frame is separated into a left rear frame having a left back support positioned on the left side of the backrest and a right rear frame having a right back support positioned on the right side of the backrest. The bases are provided integrally with the frame, and the left and right bases are held so as not to be displaced back and forth by fitting bosses protruding sideways into boss holes opening sideways.
A chair according to claim 1 or 2. A base portion of each of the left and right rear frames is formed with a side wall that overlaps the side surface of the base and a rear wall that overlaps the rear surface of the base. Side engagement grooves are formed, and side projections that fit into the side engagement grooves are provided on the left and right side surfaces of the base.
A chair according to claim 3. The base is fixed to the upper end of the leg strut made up of a gas cylinder, and an elevating lever for unlocking the gas cylinder and adjusting the height of the base is arranged so as not to protrude above the base. and the top surface of the base is entirely covered by the base of the rear frame or the base of the front frame or both bases.
A chair according to any one of claims 1-4. The bases of the left and right rear frames are fixed to the base by bolts that are inserted from above into the bases,
A pair of left and right front frames are connected to a common base, and bolts for fixing the rear frame are covered from above by the base of the front frame.
A chair according to any one of claims 3-5.

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