JP7064298B2 - Chair - Google Patents

Description

The present invention relates to a chair equipped with an armrest device.

In a chair with an armrest device, the part of the chair to which the armrest device is attached varies, but in a locking chair in which the backrest tilts backward, the armrest device is attached to the back frame to which the backrest is attached.

As an example, Patent Document 1 discloses that the inward facing portion of the armrest device is fixed to the upper surface of a portion of the back frame behind the rotation fulcrum with a screw (bolt). On the other hand, in Patent Document 2, an armrest device mounting hole is provided on the side surface of the back frame behind the rotation fulcrum, and a boss body protruding inward of the armrest device is fitted into the armrest device mounting hole. It is described that the boss body and the back frame are fixed with screws. In either case, the screw is inserted through the back frame from below.

Japanese Patent No. 5378759 JP-A-2017-64035

When the armrest device is attached to the back frame as in Patent Documents 1 and 2, the posture of the armrest device changes with the backward tilt of the backrest, so that the posture of the arm of the seated person does not change during locking. There is an advantage that the armrest device has an excellent usability.

However, in the configuration in which the armrest device is fixed to the upper surface of the back frame as in Patent Document 1, a space for fixing the armrest device is required on the back frame, so that other members are close to the upper surface of the back frame. If it is, it cannot be attached, which causes a problem of inferior versatility. On the other hand, in Patent Document 2, since the side surface of the back frame is open to the outside, the armrest device can be mounted even if there is no space on the back frame, and the application target is wide and versatile. Can be said to be high.

The present invention has been made in view of such a situation, and attaching an armrest device to the side surface of the back frame does not provide an improved configuration such as increasing the strength while following the concept of Patent Document 2. Is to be.

The chair of the present invention is
" A back frame that is rotatably connected to a base provided at the upper end of the leg device and an armrest device attached to the back frame are provided, and the armrest device is provided with an armrest at the upper end. It has an inward facing portion that extends from the lower end of the armrest toward the back frame. "
It is a basic configuration.

The invention of claim 1 is based on the above basic configuration.
"The back frame is connected to the base by left and right horizontally long support shafts so as to rotate around the front end portion thereof, and the front portion of the side surface of the back frame including the through hole of the support shaft is provided. , The elbow mounting hole is formed in the part of the stepped-down part behind the through hole, which is formed as a stepped-down part shifted inward to the left and right.
A flange overlapping the stepped portion of the back frame and a boss body that fits into the elbow mounting hole so as not to be displaced are provided at the tip of the inward facing portion of the armrest device facing the back frame. The front part and the boss body of the inward facing part are fixed with bolts,
In addition, a recessed portion surrounding the through hole of the support shaft is formed deeper than the stepped-down portion in the front portion of the back frame, and an auxiliary screw having a head parallel to the support shaft is formed in the recessed portion. However, while the head and the support shaft are attached so as to partially overlap when viewed from the axial direction of the support shaft,
The cover that overlaps the stepped portion when the armrest device is not attached is provided with an engaging claw that elastically deforms and engages with the head of the auxiliary screw. "
It is configured as.

The invention of claim 2 is claimed in claim 1 .
"The elbow mounting hole is located behind and above the through hole, and the flange of the inward facing portion greatly protrudes forward and downward from the tip of the inward facing portion."
It is configured as.

When the armrest device is attached to a portion of the back frame behind the rotation fulcrum, the load of the armrest device acts on the back frame as a bending moment and a torsional force. The bending moment increases as the mounting position of the armrest device moves away from the rotation fulcrum of the back frame. Similarly, the deformation due to twisting also increases as the mounting position of the armrest device moves away from the rotation fulcrum of the back frame.

However, in each invention of the present application, since the armrest device is attached to the back frame at the front portion very close to the rotation fulcrum of the back frame, the bending moment acting on the back frame can be almost eliminated and the torsional deformation can be achieved. Can be prevented. Therefore, the load on the back frame can be reduced and the support strength of the back frame to the armrest device can be improved.

Further, in the present invention, since the entire stepped-down portion of the back frame is covered with the flange of the inward facing portion, a cover for closing the through hole through which the support shaft penetrates is unnecessary, and the number of members is reduced accordingly. The structure can be simplified. Since the steps are invisible to the public, the aesthetics do not deteriorate.

The flange of the inward facing portion can act as a resistance against the tilting of the inward facing portion, but since the flange projects downward from the back frame, if the load acting on the elbow rest tries to tilt the inward facing portion downward, The flange stretches against the stepped-down portion of the back frame, which acts as a resistance against the inward tilting portion. Therefore, it is possible to improve the mounting strength of the inward facing portion with respect to the base.

Since the armrest device is an optional item, it may not be attached to the chair. In this case, it is necessary to attach a cover to the stepped portion to maintain the aesthetic appearance. On the other hand, for the support shaft connected to the back frame as a base, some kind of retaining means is required. With respect to these, in the present invention , one auxiliary screw can be used for both mounting the cover and preventing the support shaft from coming off, so that the structure can be simplified accordingly .

A load acting on the armrest acts on the mounting portion of the armrest device in the back frame, but in the embodiment , since the vertical width of the mounting portion of the armrest device in the back frame is large, the back to the armrest device is large. The support strength of the frame can be significantly improved. Therefore, as described above, the robustness of the back frame can be improved in combination with the fact that the bending moment and the torsional deformation with respect to the back frame can be eliminated.

It is a figure which shows the appearance of a chair, (A) is a perspective view, (B) is a front view, (C) is a plan view. It is a separation perspective view of a chair. (A) is a perspective view with the armrest device attached to the back frame, and (B) is a separated perspective view. (A) and (B) are perspective views showing the structure of the back frame, and (C) is a perspective view showing the structure of the inward facing portion. (A) is a separated perspective view of the back frame and the inward facing portion as viewed from the front, and (B) is a perspective view of the inward facing portion as viewed from below. (A) is a separated perspective view of the back frame and the inward facing portion as viewed from below, and (B) is a perspective view of the inward facing portion as viewed from below. (A) is a vertical sectional front view cut at the axial center portion of the bolt for fixing the armrest device, and (B) is a vertical sectional front view cut at the axial center portion of the support shaft. It is a figure which shows the correspondence when the armrest device is not attached, (A) is a perspective view with a cover attached, (B) is a perspective view with a cover separated, (C) is an axial center part of a support shaft. It is a vertical sectional front view cut by.

(1). Overview Next, embodiments of the present invention will be described with reference to the drawings. First, an outline will be described. This embodiment is applied to a swivel chair that is frequently used in offices. The chair is provided with a seat 1, a leg device 2, and a backrest 3 as basic elements, and the back frame 6 is freely tilted backward and connected to a base 5 fixed to the upper end of a leg support (gas cylinder), and the backrest is attached to the back frame 6. 3 is attached. Although casters are provided at the tips of the branch rods constituting the leg device 2, only one caster is displayed in FIGS. 1 (A) and 1 (B).

As can be clearly understood from FIGS. 2 and 3, the back frame 6 is composed of a front member 6a and a rear member 6b. The backrest 3 is attached to the rear member 6b while being connected by the support shaft 8. As shown in FIG. 2, the seat 1 is supported by the outer shell 9, and the outer shell 9 is attached to an intermediate member 10 connected to the base 5 and the back frame 6. Therefore, in the present embodiment, the seat 1 tilts backward while retreating in conjunction with the locking of the backrest 3. Of the front and rear members 6a and 6b constituting the back frame 6, the front member 6a is, for example, an aluminum die-cast product, and the rear member 6b is a resin molded product, but the material can be arbitrarily set.

The left and right forward arms 7 are integrally connected via a tubular portion 11 and a load receiving portion 12. A spring unit (not shown) is in contact with the load receiving portion 12 from the front, and the backrest 3 is locked by expanding and contracting the spring unit. The back frame 6 may have an integral structure as a whole, or may have a structure separated into left and right members.

The armrest device 13 is attached to the front portion 7a of the left and right forward-facing arms 7 constituting the back frame 6. The armrest device 13 includes a support unit composed of a tubular outer elbow strut 14 and an inward facing portion 15 integrally provided at the lower end thereof, and an inner elbow strut 16 is arranged inside the outer elbow strut 14. , An elbow pad 17 is attached to the upper end of the inner elbow support 16. The support unit including the outer elbow support 14 and the inward facing portion 15 is, for example, an aluminum die-cast product (it is also possible to use a resin product).

The armrest device 13 includes a movable armrest and a fixed armrest 17, but this embodiment is applied to the movable armrest. However, FIG. 2 shows a fixed armrest device for reference.

Further, in the present embodiment, the elbow rest 17 is movable in height and can be moved back and forth and horizontally. Therefore, for example, as shown in FIG. 1 (B), a lever 18 for releasing the lock when adjusting the height is provided forward at the upper end portion of the inner elbow support column 16. It is also possible to share the members between the movable type and the fixed type. It is also possible to adjust only the height of the elbow rest 17 and make it a type that cannot move horizontally.

(2). Mounting structure of the armrest device Next, the mounting structure of the armrest device 13 will be described mainly with reference to the drawings after FIG. The armrest device 13 is attached to the front portion 7a of the forward arm 7 in the back frame 6, but as shown in FIGS. 4A and 4B, for example, the front portion 7a of the forward arm 7 to which the armrest device 13 is attached is attached. Has a large vertical width in a state of being swollen downward, and a through hole 20 into which the support shaft 8 is fitted is formed on the front end side and in a lower portion.

The front portion 7a (mounting portion of the armrest device 13) of the forward arm 7 is a stepped-down portion 21 that is slightly displaced inward to the left and right by a slight dimension (several mm), while the inward facing portion 15 of the armrest device 13 is provided. A flange 22 that exactly overlaps the stepped-down portion 21 is formed at the tip of the. The flange 22 does not exist at the upper end portion of the inward facing portion 15, but extends to both front and rear sides of the inward facing portion 15 and downward.

Therefore, to be precise, the stepped-down portion 21 is blocked by the tip surface of the inward facing portion 15 and the flange 22. As shown in FIG. 7A, a fitting step portion 23 close to the inner peripheral surface of the step drop portion 21 is formed on the outer peripheral portion of the flange 22 and the upper end edge of the inward facing portion 15. Further, as clearly shown in FIG. 7A, the flange 22 becomes thicker toward the outer end.

As shown in FIGS. 4A and 4B, the stepped-down portion 21 has a recessed portion 24 communicating with the through hole 20 of the support shaft 8 and an elbow mounting hole 25 located above and behind the recessed portion 24. And are formed. The recessed portion 24 is formed so as to surround the through hole 20, and the through hole 20 is in a state of opening to the bottom of the recessed portion 24. The elbow mounting hole 25 is formed in a rectangular shape that is elongated in the front-rear direction when viewed from the side. Below the elbow mounting hole 25 (behind the recess 24), a relief hole 26 is formed to save material.

On the other hand, as shown in FIGS. 4C and 4D, a square boss body 27 that fits into the elbow mounting hole 25 of the forward arm 7 is projected from the tip surface of the inward facing portion 15 of the armrest device 13. The nut 29 is held non-rotatably in the square hole 28 formed on the upper surface of the boss body 27, and the bolt 30 inserted from below into the forward arm 7 and the boss body 27 is screwed into the nut 29 to inward the armrest device 13. The portion 15 is fixed to the front portion 7a of the forward facing arm 7.

As is clearly shown in FIG. 7A, a countersunk hole 31 into which the head of the bolt 30 is inserted is formed on the lower surface of the front portion 7a of the forward facing arm 7. Further, in the present embodiment, a metal joint plate 32 extending left and right is arranged at the tip of the inward facing portion 15 of the armrest 17 so as to penetrate the flange 22 , and one end of the joint plate 32 is a boss body. It is overlapped on the lower surface of 27 and is sandwiched and fixed between the boss body 27 and the forward arm 7, and the other end of the joint plate 32 is fixed to the lower surface of the inward facing portion 15 of the armrest device 13 with a screw 33. ing.

Even if a load exceeding the usage limit is applied to the armrest 17 and the boss body 27 breaks at the base thereof, the armrest device 13 and the forward arm 7 are connected by a joint plate 32, so that the armrest device 13 is separated from the chair. This can prevent a great danger to the user. Therefore, although the joint plate 32 is a safety measure product, it also functions as a reinforcing member under normal use conditions.

Of the inward facing portion 15 of the armrest device 13, the portion where the joint plate 32 is fixed by the screw 33 is a recess 34 that is hollowed upward, and the joint plate 32 is a screw 33 on the bottom surface of the recess 34. It is fixed. The walls 34a located on both front and rear sides of the recess 34 are inclined so as to be lowered toward the flange 22. Therefore, the inward facing portion 15 has a sturdy structure as a whole.

As shown in FIG. 6, a group of recesses for saving material is formed on the lower surface of the inward facing portion 15 of the armrest device 13, and the portion between the adjacent recesses is ribbed. It has become.

(3). Correspondence when the armrest device is not used As shown in FIG. 4 (B), the recessed portion 24 of the front portion 7a of the forward facing arm 7 is divided into upper and lower portions by the rib 35, and the rib 35 is partially divided. After excision, an auxiliary screw 36 having a pot-shaped head 36a is screwed into the excised portion as shown in FIG. 7 (B). By bringing the head 36a into contact with the rib 35, the auxiliary screw 36 keeps the screwing depth constant and prevents it from falling off.

Further, the head 36a of the auxiliary screw 36 protrudes from the upper and lower sides of the rib 35. Further, when viewed from the axial direction of the support shaft 8, the head 36a of the auxiliary screw 36 and the support shaft 8 partially overlap each other. Therefore, the support shaft 8 is prevented from coming off by the auxiliary screw 36.

As is clearly shown in FIG. 7, the support shaft 8 is fitted in the through hole 20 with a considerable length, but the distance from the end face of the support shaft 8 to the head 36a of the auxiliary screw 36 is the support shaft 8 or the through hole. It is much shorter than the size that fits in 20. Then, when the support shaft 8 moves in the axial direction for some reason, the support shaft 8 comes into contact with the head 36a of the auxiliary screw 36 and stops moving, but the movable distance of the support shaft fits into the through hole 20. Since it is much smaller than the above dimensions, the connection strength between the support shaft 8 and the forward arm 7 does not decrease even if the support shaft 8 shifts in the axial direction.

The flange 22 of the forward facing portion 15 in the armrest device 13 can also function as a stopper against the movement of the support shaft, but since the auxiliary screw 36 is firmly screwed into the forward facing arm 7, the support shaft 8 cannot come off even if it hits the head 36a. not. Therefore, it is possible to reliably prevent the support shaft 8 from coming off.

Since the armrest device 13 is an optional item, it may not be attached to the chair. In this case, as shown in FIG. 8, the front portion of the forward-facing arm 7 is covered with a resin cover 37. Therefore, the cover 37 has the same side view shape as the stepped-down portion 21, and is fitted into the stepped-down portion 21 so that the cover 37 and the portion behind the cover 37 have the same surface shape.

As shown in FIG. 8B, the cover 37 has a projecting piece 38 that penetrates the inside of the stepped-down portion 21, whereby the cover 37 is accurately positioned. Further, a pair of engaging claws 39 that engage with the head 36a of the auxiliary screw 36 screwed into the recessed portion 24 from both the upper and lower sides are projected inward. By gripping the head 36a of the auxiliary screw 36 with the pair of engaging claws 39, the cover 37 is held so as not to fall off.

The tip surface of the engaging claw 39 is an inclined surface 39a. Therefore, when the cover 37 is set so as to overlap the step-down portion 21, the engaging claw 39 escapes and rotates once due to the guide action of the inclined surface 39a, and when the cover 37 overlaps the step-down portion 21, the engaging claw 39 becomes Return to the original posture and grasp the head 36a of the auxiliary screw. Since the auxiliary screw 36 is shared for attaching the cover 37 and preventing the support shaft 8 from coming off, the number of member points can be suppressed and the structure can be simplified.

The auxiliary screw 36 is screwed into the forward arm 7 regardless of the attachment of the armrest device 13. As a result, the above-mentioned function of preventing the support shaft 8 from coming off is exhibited. Since the head 36a of the auxiliary screw 36 is located on the inner side (back side) of the flange 22, the engaging claw 39 also has a certain length. Therefore, when the cover 37 is attached / detached, the bending and deformation of the engaging claw 39 can be ensured, the attachment / detachment can be facilitated, and the breakage can be prevented. The rib 35 is omitted in FIG. 8C.

As shown in FIG. 8B, the rear end portion of the cover 37 is provided with a positioning protrusion 40, while the step-down portion 21 of the forward arm 7 is provided with a positioning hole 41 into which the positioning protrusion 40 is fitted. There is. Therefore, the cover 37 is accurately positioned by the protrusion 38 and the positioning protrusion 40.

(4). Summary In the above configuration, since the armrest device 13 is fixed to the front portion 7a of the forward arm 7, the load on the armrest device 13 hardly acts as a moment on the forward arm 7. Therefore. , The support strength of the armrest device 13 by the forward arm 7 can be improved.

Further, in the present embodiment, the cover for closing the through hole 20 through which the support shaft 8 is inserted is unnecessary, and the front portion 7a of the forward facing arm 7 is closed by the inward facing portion 15 of the armrest device 13, so that the number of members is increased. It can be reduced and the structure can be simplified.

Further, the load applied to the armrest device 13 is used as a downward moment as shown by the arrow 42 in FIG. 7A, but since the flange 22 protrudes downward, the downward moment 42 is indicated by the arrow 43. As described above, it acts as a force to bring the downward overhanging portion of the flange 22 into close contact with the forward arm 7. Further, in the present embodiment, since the downward overhanging dimension of the flange 22 is large, it is possible to firmly support the moment and secure high support strength.

Since the front portion 7a of the forward-facing arm 7, which is the mounting portion of the armrest device 13, has a large vertical width, the forward-facing arm 7 can disperse and support the load acting on the armrest device 13 over a wide area. can. Thereby, even higher support strength can be obtained.

When the elbow mounting hole 25 is arranged behind and above the through hole 20 as in the embodiment, the portion of the front portion 7a of the forward arm 7 below the elbow mounting hole 25 is the inward facing portion 15 of the armrest device 13. It is further advantageous in terms of strength because it can function as a support portion for the moment acting on the surface. That is, the support strength of the armrest device 13 can be improved while making the front portion 7a of the forward arm 7 compact by making the front-rear distance between the through hole 20 and the elbow mounting hole 25 as small as possible.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, in the embodiment, the boss body 27 is fixed to the front portion 7a of the forward arm 7 with vertically longitudinal bolts, but it is also possible to fix the boss body 27 with a bolt penetrating in a horizontal posture.

The invention of the present application can be actually embodied in a chair. Therefore, it can be used industrially.

5 Base 6 Back frame 7 Forward arm that constitutes the back frame 8 Support shaft 13 Armrest device 14 Outer elbow support 15 Inward facing part that constitutes the armrest device 16 Inner elbow support 17 Elbow pad 20 Through hole 21 Step drop part 22 Flange 24 Recess Part 25 Elbow mounting hole 27 Boss body 29 Nut 30 Bolt 36 Auxiliary screw
32 joint plate
36a Auxiliary screw head 37 Cover 39 Engagement claw

Claims (2)

The back frame is slantably connected to the base provided at the upper end of the leg device, and the armrest device is attached to the back frame. It is configured to have an inward facing portion extending from the lower end portion of the armrest toward the back frame.
The back frame is connected to the base by left and right horizontally long support shafts so as to rotate around the front end portion thereof, and the front portion of the side surface of the back frame including the through hole of the support shaft is designated. The elbow mounting hole is formed in the part of the stepped-down part behind the through hole, which is formed as a stepped-down part shifted inward to the left and right.
A flange overlapping the stepped portion of the back frame and a boss body that fits into the elbow mounting hole so as not to be displaced are provided at the tip of the inward facing portion of the armrest device facing the back frame. The front part and the boss body of the inward facing part are fixed with bolts,
In addition, a recessed portion surrounding the through hole of the support shaft is formed deeper than the stepped-down portion in the front portion of the back frame, and an auxiliary screw having a head parallel to the support shaft is formed in the recessed portion. However, while the head and the support shaft are attached so as to partially overlap when viewed from the axial direction of the support shaft,
The cover that overlaps the stepped portion when the armrest device is not attached is provided with an engaging claw that elastically deforms and engages with the head of the auxiliary screw.
Chair. The elbow mounting hole is located behind and above the through hole, and the flange of the inward facing portion greatly protrudes forward and downward from the tip of the inward facing portion.
The chair according to claim 1 .

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