JP7414394B2 - Chair - Google Patents

Description

The present invention relates to a chair equipped with a lumbar support device.

2. Description of the Related Art In chairs equipped with a backrest, it is widely practiced to provide a lumbar support device that supports the lumbar region of a seated person from behind. The structure of the lumbar support device varies greatly depending on the structure of the back.

For example, Patent Document 1 discloses that in a configuration in which a backrest is attached to a back frame having back columns arranged in the middle portion between the left and right sides, a lumbar pad is attached to the back columns in a height-adjustable manner. Patent Document 1 has the advantage of being able to firmly support the lumbar pad because the back support is a support member for the lumbar pad.

Japanese Patent Application Publication No. 2005-152087

Now, when attaching a backrest to a back frame equipped with a back support, the back support can take a variety of forms from the perspective of design, and it can also be made of various materials, such as resin or die-cast aluminum. is used.

Although Patent Document 1 has the above-mentioned advantages, in Patent Document 1, the back strut uses metal pipe material or bar material, so if the back strut is made of resin or aluminum die-casting, cannot be said to be applicable as is.

The present invention was made against the background of this current situation, and it is an object of the present invention to provide a lumbar support device that can be easily applied to back supports made of resin or die-cast aluminum and has excellent functionality and aesthetics. It is.

The invention of claim 1 is:
"It has a seat, a backrest, and a back frame to which the backrest is attached, and the back frame has a vertically longitudinal back support located at the middle between the left and right, and the backrest is attached to the back support. A lumbar support device is installed to support you from behind.
This is the basic configuration , and in this basic configuration,
"The lumbar support device includes a vertically longitudinal rail member provided with multiple stages of height adjustment engagement parts, a lumbar pad attached to the rail member so that the height can be adjusted , and a lumbar pad inside which the rail member is attached. It has a fixedly arranged upper and lower elongated housing with a forward opening,
A vertically longitudinal recess, in which the housing is housed over its entire height, is formed in the front face of the back support and opens forward .
The structure is as follows.

The invention of claim 2 is, in claim 1,
"A slider to which the lumbar pad is fixed is attached to the rail member so as to be movable up and down while surrounding the rail member , and the slider is also attached to the housing so that it can slide up and down."
The structure is as follows.

The invention of claim 3 is an independent invention, and has the same basic configuration as claim 1,
“The lumbar support device includes a vertically longitudinal rail member provided with multiple stages of height-adjusting engagement portions, and a lumbar pad attached to the rail member in a height-adjustable manner. , fixedly disposed inside a housing stored in a recess formed in the front surface of the back strut;
and a first engaging portion that holds the rail member in an immovable manner is provided at a lower end of the rail member and a lower end of the housing, and a lower end of a recess provided in the lower end of the housing and the back support is provided. The part is provided with a second engaging part that holds the lower end part of the housing in an immovable manner,
The upper end of the rail member and the upper end of the housing are fastened together to the back support with a single screw.
The structure is as follows.

Moreover, the invention of claim 4 is:
``Equipped with a seat and a backrest, a back frame to which the backrest is attached and has a back support located in the middle between the left and right, and a lumbar support device attached to the back support and supporting the backrest from behind,
The lumbar support device includes a vertically longitudinal, forward-opening case-like housing fixed to the back support, and a lumbar pad is height-adjustably attached to a rail member fixed to the housing. ing"
In the basic configuration,
"A vertically longitudinal recess in which the housing is housed over its entire height is formed in the front face of the back strut and opens forward,"
A slider to which the lumbar pad is fixed is attached to the rail member so as to be movable up and down,
The slider and the housing are separated from each other to allow vertical movement of the slider when no pressing force of a person sitting on the lumbar pad is applied, and engage with each other when a pressing force of a person sitting on the lumbar pad is applied. A locking means is provided to keep the slider from moving up and down.
The structure is as follows.

The invention of claim 5 has the same basic configuration as claim 4 ,
" A slider to which the lumbar pad is fixed is attached to the rail member so as to be movable up and down; the slider is attached to the housing so as to be slidable up and down;
The slider and the housing are separated from each other when no pressing force from the seated person is acting on the lumbar pad, allowing the slider to move up and down, and when the pressing force from the seated person is applied to the lumbar pad, they engage and move the slider. It is equipped with a locking means that prevents it from moving up and down.
The structure is as follows.

In the first aspect of the invention, since the entire housing can be stored in the recess of the back support, exposure of the lumbar support device can be suppressed and the appearance can be improved. Furthermore, since the distance between the back support and the backrest can be narrowed compared to the case where there is no recess, it can be said that the size of the chair as a whole can be suppressed.

Furthermore, since the lumbar support device can be made into a unit using the housing, there is an advantage that the lumbar support device can be easily assembled to the back support. Furthermore, since the rail member is hidden within the housing, it has the advantage of preventing or suppressing objects from hitting the rail member or the movable member attached to it, improving the reliability of movement, and preventing objects from hitting the rail member or the movable member attached to it. This has the advantage of eliminating the problem of fingers getting caught.

When the configuration of claim 2 is adopted, the slider is guided in elevation by the housing that is wider than the rail member, so that smoothness in the elevation of the lumbar pad can be improved.

When the invention of claim 3 is adopted, the lower end of the rail member and the lower end of the housing are held by the first engaging part by fitting or the like so that they cannot be displaced, and the lower end of the housing is held by the second engaging part. The rail member and the housing are fixed to the support column simply by tightening their upper parts together with a single screw, since the rail member and the housing are fixed to the column by fitting them into the engaging part of the recess. There is. Therefore, the lumbar support device can be easily attached.

Now, in a lumbar support device in which the height of the lumbar pad can be adjusted against the elasticity of a locking member, the lumbar pad may shift and move when the body pressure of a seated person is applied. However, if a lever is used to release the lock, the structure becomes complicated and the cost increases. On the other hand, when the configuration of claim 4 is adopted, when the pressing force of the seated person acts on the lumbar pad, the lumbar pad is held so that it cannot move up and down. This can prevent it from shifting or moving.

Moreover, in the invention of claim 5, since the lumbar support device can be made into a unit as described above, the lumbar support device can be manufactured with high precision regardless of the dimensional accuracy of the back support. Therefore, the lumbar pad can be easily raised and lowered, and high quality can be ensured.

FIG. 1 is a diagram showing the chair of the first embodiment, in which (A) is a front perspective view, (B) is a rear perspective view, and (C) is a rear perspective view of only the back. (A) is a perspective view showing the frame, (B) is a rear perspective view, and (C) is an isolated perspective view. Figures showing the lumbar support device, (A) is an exploded perspective view seen from the front, (B) is an exploded perspective view seen from the rear, and (C) is a rear view seen from the CC direction of (B). It is. (A) is a partially separated perspective view, and (B) is an separated perspective view with some members attached to the lumbar pad. (A) is a partially enlarged front view of the housing, (B) is a front view with the lumbar pad omitted, and (C) is an isolated front view with the lumbar pad omitted. (A) is a lower perspective view of the lumbar support device, (B) is a partially separated perspective view, and (C) is a longitudinal side view. It is a figure which shows the chair of 2nd Embodiment, (A) is a front perspective view, (B) is a side view, and (C) is a top view. (A) is a front view, and (B) is a rear view. Figures illustrating the lumbar support device of the second embodiment, (A) is an exploded perspective view seen from the front, (B) is an exploded perspective view seen from the rear, and (C) is a CC view direction of (B). FIG. (A) is an exploded perspective view, (B) is a perspective view with some members separated, and (C) is a longitudinal side view.

Next, embodiments of the present invention will be described based on the drawings. In the following, words such as front and back and left and right are used to specify directions, but these directions are specified as seen from a person sitting normally. The front view direction is a direction facing the seated person.

(1). Overview of Chair The chair of this embodiment is applied to a rotating chair that is often used in offices and the like. As shown in FIGS. 1 and 2, the chair includes a seat 1, a backrest 2, a back frame 3 to which the backrest 2 is attached, and a leg device 4 with casters as main components. A lumbar support device 5 is arranged behind the backrest 2. The chair also includes an armrest device 6 and a headrest (or shoulder rest) 7 as optional items.

For example, as shown in FIG. 1, a base body 9 is fixed to a leg support (gas cylinder) 8 arranged in the center, and a back frame 3 is connected to the base body 9 via a joint member 10 so as to be tiltable backward. Therefore, the chair of this embodiment is of a rocking type in which the backrest 2 tilts backward against the elastic means.

The back frame 3 includes a vertical and longitudinal back support 11 located at the left and right intermediate portions, a left and right longitudinal upper support 12 attached to the upper end of the back support 11 so as to be able to rotate horizontally, and a left and right lower support provided integrally at the lower end of the back support 11. 13, both left and right ends of the upper support 12 and the tip of the lower support 13 are free ends, and the corner part of the backrest 2 is connected to the tip of the upper support 12 and the tip of the lower support 13. is connected to. Therefore, the backrest 2 is attached to the back frame 3 in a four-point supported state.

When the pressing force of a seated person acts biasedly on the right side or left side of the backrest 2, the upper support 12 horizontally pivots and the backrest 2 can be torsionally deformed. Therefore, the backrest 2 twists and deforms following the movement of the user's body. The back support 11 and the upper support 12 are made of synthetic resin, and the back support 11 can also be twisted and deformed by the pressing force of the seated person. Note that the back support 11 and lower support 13 are covered with a cover from behind.

As shown in FIG. 1(C), the upper support 12 is curved in a plan view so as to be concave toward the front (inflate toward the rear), and a backrest 2 is provided at both left and right ends of the upper support 12. Both left and right ends of are connected. Therefore, there is a large space between the upper support 12 and the backrest 2. The existence of this space allows the upper end portion of the backrest 2 to extend and deform backward due to the pressing force (body pressure) of the seated person.

On the other hand, as clearly shown in FIG. 4, for example, the lower support 13 is curved so that the upper surface and the lower surface become higher toward the tip when viewed from the rear, and the lower surface of the left and right lower supports 13 and the back strut 11 are curved. The lower surface formed by the lower surface (that is, the lower surface of the back frame 3) is also a curved surface that swells downward. Therefore, the back frame 3 has a shape similar to an anchor as a whole.

As shown in FIGS. 1(C) and 6(C), the backrest 2 has a cushioning material 14 stretched over the front and back surfaces of a back plate (back inner shell) 2a made of synthetic resin, and the entire front and back sides are covered with a bag-shaped outer shell. It has a structure covered with wood.

(2). Lumbar Support Device Next, the lumbar support device 5 will be explained mainly with reference to FIGS. 3 to 6. As shown in FIG. 3, the lumbar support device 5 includes a lumbar pad 22 that supports the backrest 2 from behind, a holder member 24 fixed to the rear surface of the lumbar pad 22 with left and right screws 23, and the lumbar pad 22 and the holder member 24. The housing 27 includes a rail member 25 and a clip member 26 that are disposed between the housing 25 and the clip member 26, and a housing 27 that has a case shape that opens forward and stores the holder member 24 and the rail member 25 inside. These are molded products of synthetic resin.

The holder member 24 and the clip member 26 are integrally fixed, hold the rail member 25 from the front and rear, and are attached to the rail member 25 so as to be movable up and down. Therefore, the holder member 24 and the clip member 26 constitute the slider described in the claims.

As shown in FIG. 3, a vertical longitudinal recess 28 is formed in the front surface of the back support 11, into which the vertical longitudinal housing 27 is completely fitted over its entire height . A downward protrusion 29 is formed on the lower surface of the housing 27, while an engagement hole 30 into which the downward protrusion 29 fits is formed on the lower surface of the recess 28 of the back support 11. Further, an engagement recess 31 recessed toward the front is formed on the rear surface of the upper end of the housing 27, while an engagement stepped portion 32 overlapping the engagement recess 31 is formed in the recess 28 of the back support 11. are doing. Although the bottom surface of the recess 28 has an uneven shape in which peaks and valleys are alternately connected vertically, it may be a flat surface.

The rail member 25 has a vertically long strip-like shape, and as shown in FIGS. 3(A) and 3(B), the lower end of the rail member 25 has a locking protrusion 34 that is approximately T-shaped in plan view and has left and right wing plates 33. On the other hand, as shown in FIG. 3(A), a substantially T-shaped engagement groove 35 into which the locking protrusion 34 fits is formed at the bottom of the housing 27. Therefore, the lower end of the rail member 25 is held against the lower end of the housing 27 so as not to be displaced in any of the front, rear, left, and right directions.

As shown in FIG. 3, the upper end of the rail member 25 is formed with a head portion 36 tilted backwards, while the upper end of the housing 27 is provided with a groove 37 into which the head portion 36 is fitted without being able to shift from side to side. The head portion 36 and the housing 27 are fastened together to the engagement step portion 32 of the engagement recess 31 in the back support 11 with one screw 38. Therefore, the rail member 25 and the housing 27 are fixed to the back support 11 with a single screw 38 without any play.

In this embodiment, the locking protrusion 34 provided on the rail member 25 and the engagement groove 35 provided on the housing 27 are examples of the first engagement portion described in the claims, and the downward protrusion provided on the housing 27 is an example of the first engagement portion described in the claims. 29 and the engagement hole 30 provided in the recess 28 are examples of the second engagement portion described in the claims. In either case, since they can be fitted and removed from the top and bottom, when the upper parts are tightened together with the screws 38, both the rail member 25 and the housing 27 are held so that they cannot be displaced in either the top, bottom, left or right directions. The first engaging part and the second engaging part can adopt various other fitting modes.

On the back surface of the rail member 25, a large number of engagement protrusions 39 are formed vertically side by side as part of height adjustment means. On the other hand, the clip member 26 is configured to hold the rail member 25 from the front and rear, and the rear portion of the rail member 25 serves as left and right locking claws 40 that engage and disengage from the engagement projections 39.

To be precise, the clip member 26 has a base plate located in front of the rail member 25, left and right side plates protruding backward from both left and right sides of the base plate, and left and right locking claws 40 integrally provided on the left and right side plates. The rail member 25 is sandwiched between the board and the locking claw 40. More specifically, as shown in FIGS. 3(A), 5(B), and 5(C), thinned ribs 25a are formed vertically and vertically on the left and right side edges of the rail member 25, while the clip member The side plate 26 is formed with a dovetail groove into which the rib 25a is slidably fitted.

The locking claw 40 has a lower end (tip) as a free end, and the height of the lumbar pad 22 is maintained by the lower end of the claw fitting between the adjacent engagement protrusions 39 . When an external force is applied in the vertical direction to the lumbar pad 22, the locking pawl 40 is elastically deformed and gets over the engagement protrusion 39. Thereby, the height of the lumbar pad 22 can be adjusted in stages.

The holder member 24 is arranged inside a surrounding frame 41 formed on the rear surface of the lumbar pad 22. A group of inward ribs 42 are formed on the left and right inner surfaces of the enclosing frame 41, while outward ribs 42 are formed on the left and right outer surfaces of the clip member 27 to fit with the inward ribs 42 and hold them so that they cannot move vertically. 43 is formed. Therefore, the clip member 27 is held and held by the holder member 24 so as not to shift in any of the up, down, right and left, and front and back directions.

For example, as shown in FIG. 3(B), flanges 44 are provided on the front and left and right sides of the holder member 24. Step portions 45 are formed on the left and right sides of the housing 27, into which the flanges 44 of the holder member 24 are fitted so as to be vertically slidable.

Further, as shown in FIG. 3(B) and FIG. 4(B), a vertical and longitudinal guide rib 46 is integrally provided at the middle position between the left and right sides of the rear surface of the holder member 24, and left and right engagement ribs are provided at both upper and lower ends of the guide rib 46. 47, as shown in FIGS. 3(A) and 5(A), on the bottom surface of the housing 27, a guide rib 46 and an engaging rib 47 cooperate to maintain the height of the lumbar pad 22. A locking portion 48 is formed.

As clearly shown in FIG. 5(A), the lock portion 48 forms a center groove 49 into which the guide rib 46 is fitted so as to be slidable up and down, and a group of lock grooves 50 into which the engagement rib 47 is fitted. . The lock groove 50 is formed by lock protrusions 51 arranged vertically, and the lock protrusions 51 are integrally formed with left and right longitudinal ribs 52 forming the center groove 49. The lock projections 51 are formed at the same height and pitch as the engagement projections 39 formed on the rear surface of the rail member 25.

When no backward external force is applied to the lumbar pad 22, the engagement rib 47 is removed from the lock groove 50 toward the front, and the lumbar pad 22 can be moved up and down. On the other hand, when the pressing force of the seated person acts on the lumbar pad 22, the rail member 25 is pushed backward and the engagement rib 47 of the holder member 24 fits into the lock groove 50. This locks the lumbar pad 22 so that it cannot move up and down.

Now, when a seated person is leaning against the backrest 2, vertical slippage may occur between the seated person's back and the backrest 2, and as a result, the lumbar pad 22 may unintentionally rise. Or it may go down. However, in this embodiment, when a seated person leans back against the backrest 2, the engagement rib 47 of the holder member 24 fits into the lock groove 50 of the housing 27, so that the lumbar pad 22 is held immovable up and down. .

Therefore, the locking means described in the claims is constituted by the engaging rib 47 and the locking part 48, but when the pressing force of a seated person acts, the rail member 25 is elastically deformed and the engaging rib 47 Since the rail member 25 engages with the locking portion 48, strictly speaking, it can be said that the rail member 25 plays the role of a spring means and forms part of the locking means. In order to ensure the free state, it is also possible to provide a spring that pushes the holder member 24 forward.

(3).Summary The lumbar support device 5 of this embodiment is entirely assembled to the housing 27 as a base material. That is, the entire structure is integrated into one unit via the housing 27. Therefore, assembly is easy and high dimensional accuracy can be ensured.

Furthermore, since the rail member 25 is built into the housing 27 and most of the housing 27 is built into the recess 78 of the back support 11, most of the base of the lumbar support device 5 is located inside the back support 11. Hidden in thick areas. Therefore, the aesthetic appearance can be improved. Furthermore, it is also possible to reduce the distance between the back support 11 and the backrest 2 to prevent the chair from becoming larger.

Furthermore, if only the vertical sliding of the clip member 26 by the rail member 25 is used as the means for vertically sliding the lumbar pad 22, the rail member 25 has a small width, so the lumbar pad 22 cannot be smoothly raised and lowered. However, in this embodiment, since the holder member 24 is held in a vertically slidable manner relative to the housing 27, which is much wider than the rail member 25, twisting can be prevented or significantly suppressed, and the lumbar The pad 22 can be raised and lowered smoothly.

In the embodiment, the lower end of the rail member 25 is fitted into the housing 27, and the lower end of the housing 27 is fitted into the back support 11, so that the lumbar support device can be attached to the back support 11 with only one screw 38. It can be fixed to Therefore, the lumbar support device 5 can be installed efficiently. Further, although an external force acts backwards on the lumbar support device 5, this external force is supported by the back strut 11, so even if it is fastened with a single screw 38, there is no concern about the installation strength of the lumbar support device 5. There isn't.

As mentioned above, if a locking means is provided to hold the lumbar pad 22 so that it cannot move up and down while a seated person is leaning against the backrest 2, the lumbar pad 22 will be prevented from moving (particularly from sliding down), improving comfort. can be improved.

(4).Second Embodiment FIGS. 7 to 10 show a second embodiment applied to a mesh type. That is, the backrest 2 has a structure in which a mesh material 54 is stretched over a back frame 53 that is open in the front and rear, and includes a lumbar support device 5, an armrest device 6, and a headrest 7, as in the first embodiment. .

The lumbar support device 5 of the second embodiment is shown in FIGS. 9 and 10. As can be understood from these figures, the structure of the lumbar support device 5 of the second embodiment is basically the same as that of the first embodiment, but the support structure of the lumbar pad 22 is different from that of the first embodiment. ing.

That is, in the first embodiment, the holder member 24 was directly fixed to the back surface of the lumbar pad 22, but in the second embodiment, a spacer frame 55 having an arcuate shape in plan view is attached to the back surface of the lumbar pad 22. , the holder member 24 is fixed to the spacer frame 55. Therefore, the rail member 25 and the clip member 26 are arranged between the holder member 24 and the spacer frame 55. Further, the spacer frame 55 is formed with an enclosing frame 41 that holds the clip member 26 so that it cannot be displaced.

As can be understood from FIG. 10(A), the left and right ends of the spacer frame 55 have thin connecting portions 56, while the left and right ends of the lumbar pad 22 have boss portions 57 into which the connecting portions 56 enter. is forming . An engaging piece 58 facing outward is formed at the tip of the connecting portion 56, while an engaging groove 59 into which the engaging piece 58 fits is formed at the back of the boss portion 57 of the lumbar pad 22 so as to face inward. It is formed to be open.

The engagement piece 58 can be easily fitted into the engagement groove 59 by narrowing the spacer frame 55. Since the pressing force exerted by the seated person acts to widen the left-right distance between the spacer frames 55, the lumbar pad 22 will not come off the spacer frames 55 due to external force.

The left and right connecting portions 56 of the spacer frame 55 are connected by a reinforcing frame 60 that overlaps the lower surface of the lumbar pad 22. Since the boss portion 57 is located at the upper end, a moment may be applied to the lumbar pad 22 that pushes the lower end backward due to the pressing force of the seated person. It can firmly support the user's body without deforming the body.

Although the embodiments of the present invention have been described above, each invention of the present application can be embodied in various other ways. For example, structural members such as the lumbar pad and the housing can be changed as appropriate depending on design requirements. In adjusting the height of the lumbar pad, it is also possible to provide a locking device that can be switched between a free state and a locked state by a lever device.

The present invention can be embodied in a chair equipped with a lumbar support device. Therefore, it can be used industrially.

2 Backrest 3 Back frame 5 Lumbar support device 11 Back support 22 Lumbar pad 24 Holder member forming the slider 25 Rail member 26 Clip member forming the slider 27 Housing 28 Recess 29 Downward protrusion forming the second engaging portion 30 No. 2 Engagement hole forming the engagement part 34 Locking projection forming the first engagement part 35 Engagement groove forming the first engagement part 39 Engagement projection 40 Locking claw 47 Engagement forming the locking means Rib 48 Lock part constituting the locking means

Claims (5)

It has a seat, a backrest, and a back frame to which the backrest is attached, and the back frame has a vertically longitudinal back support located in the middle between the left and right, and the backrest is attached to the back support. A configuration in which a lumbar support device is installed to support the
The lumbar support device includes a vertically longitudinal rail member provided with multiple stages of height adjustment engagement parts, a lumbar pad attached to the rail member so as to be height adjustable , and the rail member fixed inside. It has a vertically longitudinal and forward-facing opening housing arranged as a top and bottom,
A vertically longitudinal recess in which the housing is housed over its entire height is formed in the front face of the back strut, and is opened forward.
Chair. A slider to which the lumbar pad is fixed is attached to the rail member so as to be movable up and down while surrounding the rail member, and the slider is also attached to the housing so as to be slidable up and down.
A chair according to claim 1. It has a seat, a backrest, and a back frame to which the backrest is attached, and the back frame has a vertically longitudinal back support located in the middle between the left and right, and the backrest is attached to the back support. A configuration in which a lumbar support device is installed to support the
The lumbar support device includes a vertically longitudinal rail member in which height adjustment engagement portions are provided in multiple stages, and a lumbar pad that is attached to the rail member so that the height can be adjusted, and the rail member includes: fixedly disposed inside a housing stored in a recess formed in the front surface of the back strut;
and a first engaging portion that holds the rail member in an immovable manner is provided at a lower end of the rail member and a lower end of the housing, and a lower end of a recess provided in the lower end of the housing and the back support is provided. The part is provided with a second engaging part that holds the lower end part of the housing in an immovable manner,
The upper end of the rail member and the upper end of the housing are fastened together to the back support with a single screw.
Chair. It includes a seat and a backrest, a back frame to which the backrest is attached and has a back support located in the middle between the left and right sides, and a lumbar support device attached to the back support and supporting the backrest from behind,
The lumbar support device includes a vertically longitudinal, forward-opening case-like housing fixed to the back support, and a lumbar pad is height-adjustably attached to a rail member fixed to the housing. It is a chair that has
A vertically longitudinal recess in which the housing is housed over its entire height is formed in the front face of the back strut, and is opened forward;
A slider to which the lumbar pad is fixed is attached to the rail member so as to be movable up and down,
The slider and the housing are separated from each other when no pressing force from the seated person is acting on the lumbar pad, allowing the slider to move up and down, and when the pressing force from the seated person is applied to the lumbar pad, they engage and move the slider. It is equipped with a locking means that prevents it from moving up and down.
Chair . It includes a seat and a backrest , a back frame to which the backrest is attached and has a back support located in the middle between the left and right sides, and a lumbar support device attached to the back support and supporting the backrest from behind,
The lumbar support device includes a vertically longitudinal, forward-opening case-like housing fixed to the back support , and a lumbar pad is height-adjustably attached to a rail member fixed to the housing. It is a chair that has
A slider to which the lumbar pad is fixed is mounted on the rail member so as to be movable up and down; the slider is mounted on the housing so as to be slidable up and down;
The slider and the housing are separated from each other when no pressing force from the seated person is acting on the lumbar pad, allowing the slider to move up and down, and when the pressing force from the seated person is applied to the lumbar pad, they engage and move the slider. It is equipped with a locking means that prevents it from moving up and down.
Chair.

Images