JP4960689B2 - Chair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure appropriate lumbar support function and fitting property even if an inner shell of a backrest is formed of a synthetic resin with low flexibility in a chair having a lumbar support part of the backrest which advances by seating. <P>SOLUTION: The inner shell is an injection molded product of a synthetic resin such as PP (polypropylene), and the lumbar support part 22 has a semi-rigid structure without slit or the like. Both sides above/below the lumbar support part 22 are formed into deformation allowance parts 55 and 53 having multiple laterally long slits 59 and 52. Both left/right ends of the lumbar support part 22 are supported by an upper link. A lower shape-retaining part 54 is continued to the lower deformation allowance part 52 from below and left/right portions close to the intermediate part of the lower shape retaining part 54 are supported by a lower link from behind. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a chair whose backrest has a structure in which a cushion is stretched on the front surface of an inner shell made of synthetic resin.

  There are various backrest structures in a chair. For example, office chairs often have a structure in which a cushion is stretched on the front surface of an inner shell (back plate) made of synthetic resin. The reason why the inner shell is made of a synthetic resin is that it can be easily mass-produced even if it has a complicated shape, and that it can maintain appropriate elasticity.

  On the other hand, in a chair that a person keeps sitting for a long time, such as an office chair, in recent years, a lumbar support function for supporting a lumbar part (or pelvis or lumbar spine) of a seated person is regarded as important. 1 and 2, by forming a large number of slits in the inner shell of the backrest so that the inner shell can be easily deformed, it is possible to easily adjust the protrusion amount and the height of the protrusion position of the lumbar support portion. Disclosed.

In addition, when a person uses a chair, he does not always sit down deeply, and often works in a state where he sits shallowly, but as a groundbreaking chair that demonstrates the lumbar support function even when seated shallowly. The applicant of the present application has proposed in Patent Document 3 that the lumbar support portion of the backrest moves forward when a person is seated.
JP 2003-79487 A JP 2005-80677 A Japanese Patent Application No. 2005-237660

  In a backrest having an inner shell, it is important for the inner shell to be easily bent and deformed in order to improve the fit of the user to the back. However, the inner shell is deformed in a side view or a side sectional view. It can be said that there are two basic elements of doing (referred to as “vertical deformation” for convenience) and deforming in plan view or plan view (referred to as “lateral deformation” for convenience).

  And, the inner shell is mainly deformed vertically to adjust the protruding amount (projecting height) or protruding height position of the lumbar support part. It is possible to eliminate the feeling of pushing up in the extended state.

  On the other hand, the inner shell mainly deforms laterally, so that the backrest can be fitted to the waist and back even if the physique is different, and the cushioning can be enhanced by elastically supporting the leaning of the body Become. Further, by combining the vertical deformation and the horizontal deformation, when the seated person twists the upper body, the backrest can be twisted and deformed following this. In general, the inner shell is gently curved in a concave shape facing forward in plan view so as to wrap around the body of the seated person (the degree of curvature increases toward the lower part). Transverse deformation is interrelated.

  The backrest does not necessarily have to be able to freely deform all the parts thereof, and it is preferable that the upper portion does not bend and deform. This is in order to support the body of the person who is seated and to prevent a problem that the upper body falls off the backrest when the body is twisted in a locked state, for example.

  Therefore, it is preferable that the upper part of the inner shell is fixed to the back frame device. Patent Documents 1 and 2 disclose that the lower end of the inner shell is the back frame as means for allowing the inner shell to be vertically deformed in this state. It is disclosed that it can be moved up and down (the inner shell made of synthetic resin does not undergo compression deformation or elongation deformation like rubber, so some means is required to allow vertical deformation. is there.).

  The present invention allows the inner shell to be deformed in a manner different from Patent Documents 1 and 2, and has been developed as a suitable configuration for the chair of the Patent Document 3, but it has been further advanced and the backrest has been developed. It is an object of the present invention to provide a chair having an improved inner shell for a back that can be applied to a chair whose lumbar support does not move forward.

  The chair of the present invention includes, as a basic configuration, a seat, a backrest formed by placing a cushion on the front surface of a synthetic resin inner shell, and a back frame device that supports the backrest from the back side. The inner shell has a lumbar support portion that can support the lumbar portion of a seated person, and the upper portion of the inner shell is held by the back frame device with almost no deformation, while the lumbar support of the inner shell The lower end part below the part is connected to the back frame device, and the inner shell is allowed to extend and deform from a form in which the lumbar support part protrudes forward in a side sectional view to a state close to flat. .

  According to the first aspect of the present invention, in addition to the basic configuration, the lumbar support of the inner shell can be easily deformed in a side sectional view shape even if the planar view shape can be easily deformed by the body pressure of the seated person. A slit that allows the lumbar support part to move forward by extending and deforming vertically on either or both sides of the inner shell of the backrest that sandwich the lumbar support part. A group is formed.

  According to a second aspect of the present invention, in the first aspect, the left and right end portions of the inner shell lumbar support in the backrest are connected to the back frame device, and the lower end portion of the inner shell is the left and right intermediate portion or the vicinity thereof is the back frame. Connected to the device.

  According to a third aspect of the present invention, in the first or second aspect, the back frame device includes a main frame that is connected to a base disposed below the seat so as to be rearwardly tiltable, and is directed upward from the main frame on the back side of the backrest. A back frame arranged to extend and a main link attached to the main frame so as to be able to turn forward about the lower end when placed by a person sitting on the back side of the lower part of the backrest. The upper part of the inner shell in the backrest is fixed to the upper end of the back frame.

  Further, in claim 3, the left and right end portions of the lumbar support portion of the inner shell in the backrest are connected to the upper link connected to the main link so as to be rotatable up and down so as to be relatively rotatable in a side view. The lower end of the inner shell in the backrest is connected to the lower link, which is connected to the main link so as to be relatively rotatable in a side view at a position below the upper link, and is relatively rotatable. The inner shell is deformed by changing the rotation posture with the link.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a group of lower slits extends in a state near the full length of the left and right below the lumbar support in the inner shell of the backrest. While the portion below the lumbar support of the inner shell is allowed to extend and deform in the vertical direction in any part of the left and right, the portion of the inner shell in the backrest that is continuous with the upper end of the lumbar support portion is Three portions of the left and right intermediate portions and the portions near the left and right ends are the deformation allowance portions having the upper slit group, and the space between the left and right side deformation allowance portions and the middle center deformation allowance portion is opened in the front and rear. It has become a space.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a cushion is stretched on the front surface of the inner shell of the backrest by an insert molding method, and the inner shell is disposed above the inner shell of the backrest. A bag-like portion into which a nut can be inserted from the front surface of the inner shell is formed. The upper portion of the inner shell is screwed into the nut and fixed to the back frame device with a screw. Further, the bag-like portion of the inner shell is closed by the nut. A cover piece that covers the female screw hole of the nut is formed on the front side of the inner shell in the bag-like portion.

  The terms “front and rear” and “left and right” are used in the claims and specification of the present application, and these terms are based on a person sitting in a normal posture on a chair.

  As a means for allowing vertical deformation in a state where the inner shell is connected to the back frame device at both upper and lower end portions, it is possible to form a horizontally long slit group on the lumbar support and both the upper and lower sides thereof. Since the lumbar support portion has low rigidity, a support member that supports the lumbar support portion from behind is required to project the lumbar support portion of the inner shell forward. That is, the lumbar support portion needs to be supported from behind in a wide range including the left and right intermediate portions.

  On the other hand, in the present invention, since the lumbar support portion of the inner shell is a semi-rigid body, only the lower end portion of the inner shell is supported, or the left and right ends of the lumbar support portion are connected to the back frame device as in claim 2. It is possible to support the occupant's lower back by connecting to, so that the structure can be simplified.

  Further, the lumbar support part is not a perfect rigid body, and the plan view form can be considerably deformed by the body pressure of the seated person, so that the lumbar support part is supported at both the left and right end parts as in claim 2 and is in a state of supporting both ends. Thus, the lumbar support can be fitted to the human body, or the lumbar support can be kept cushioned.

  If comprised like Claim 2, since the inner shell is connected with the back frame apparatus in four places, an upper end part, the right-and-left both ends of a lumbar support part, and a lower end part, it will be in the state of four-point support. However, because the upper and lower ends of the inner shell are connected to the back frame device, the lumbar support function is fully demonstrated, and the lumbar support part is supported by the back frame in the state of both-end support beams from the back. By being supported, the lumbar support is allowed to be deformed so as to be bent backward by the body pressure of the seated person, so that the fit is excellent.

  If the structure of Claim 3 is employ | adopted, since the upper and lower links rotate relatively with respect to a main frame and an inner shell, the freedom degree of a deformation | transformation of an inner shell becomes still higher, Therefore In this way, the lumbar support part is moved forward smoothly by sitting.

  If the structure of Claim 4 is employ | adopted, since the part which continues to the lower part of a lumbar support and the part which continues to the upper part of an inner shell can expand-contract vertically, the deformation | transformation of an inner shell becomes smoother. Thus, the fit can be further improved. In addition, since there is a pair of left and right openings in the upper part of the lumbar support part of the inner shell, the backrest can accurately follow the movement when the seated person twists the upper body. Can also give people a much higher feeling of use.

  By the way, as a method of attaching the inner shell of the backrest to a back frame device such as a back frame, an engaging portion such as a claw portion or an engaging hole that is elastically deformed is formed on the inner shell, and the engaging portion of the inner shell It is roughly classified into a catch method (snap engagement method) for fitting the engagement portion of the back frame device and a screw fixing (screw fixing). Of these, there are two types of screw fixing: a case where a nut is used to clamp the inner shell, and a case where a screw is screwed into a female screw hole formed in the inner shell or back frame device. Is excellent.

  On the other hand, as one of the methods of stretching the cushion on the front surface of the inner shell, there is an insert molding method in which the inner shell is set in a mold and the cushion material is injected into a mold cavity and foamed and molded. Employing this method has the advantage that a beautiful and uniform cushion layer can be obtained even if the inner shell has a complicated shape, and that the bonding step is unnecessary.

  And, when the cushion is stretched by the insert molding method and the inner shell is fixed to the back frame device with a nut and a screw in this way, since the cushion exists on the front surface of the inner shell, the screw inevitably becomes a part of the inner shell. When screwing into the nut from the back side, it is necessary to set the nut in the inner shell in a state in which the nut cannot be pulled backward. In this case, a bag-like part for loading the nut into the inner shell will be formed, but in order to secure a high fastening strength by firmly holding the inner shell with the nut, the nut is bagged from the front side of the inner shell. It is preferable to fit in the shape part.

  However, when the nut is fitted into the bag-shaped part of the inner shell from the front side, the screw hole of the nut opens to the front and rear of the inner shell, so when the cushion is manufactured by the insert molding method, the cushion enters the female screw hole of the nut. There is a possibility that screws cannot be screwed in, and it is troublesome to use a nut with a bottom in which a female screw hole is opened only on the back side of the inner shell.

  On the other hand, since the female screw hole of the nut is closed by the cover piece provided in the bag-shaped portion when configured as in claim 5, the insert molding method can be used without hindering the cushion without using a bottomed nut. In addition, the cover piece of the bag-like portion is provided on the inner shell from the beginning, and no post-processing work is required. Moreover, since the cover piece of the bag-like portion also functions as a holding member or a retaining member for the nut, it is possible to prevent the nut from dropping between the time when the nut is loaded and the time of insert molding.

  The feature of claim 5 can be widely applied to chairs using nuts for fixing to the back frame device without assuming the configuration of claims 1 to 4 (the effect of preventing the nut from falling off with the cover piece). Can also be applied to cushions that are not stretched by insert molding.)

  Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a rotary chair for office use or the like.

(1). Outline of Chair First, an outline of a chair will be described with reference to FIGS. 1A is an overall perspective view of the chair as viewed from the front, FIG. 1B is a partial rear view, FIG. 2A is a partial perspective view of the chair as viewed from the rear, and FIG. 3 and 3 are perspective views of some members.

  The chair includes a leg 1, a seat 2, and a backrest 3. The leg 1 includes a group of branch legs 4 extending horizontally and a leg column (gas cylinder) 5, and a base 6 made of a metal plate opened upward is attached to the upper end of the leg column 5. Although not shown, the seat 2 includes a resin seat inner shell (not shown), a cushion stretched on the upper surface thereof, and a seat outer shell 7 that supports the seat inner shell from below (see FIG. 2B). ).

  Left and right front support links 8 are connected to the front portion of the seat outer shell 7 so as to be rotatable relative to each other, and the left and right front support links 8 are connected to the base 6 via first left and right first support shafts 9. Has been. The first support shaft 9 is tilted backward in a side view (inclined rearward with respect to the horizontal) provided in the base 6 and is fitted into a longitudinally long slot. For this reason, the first support shaft 9 slides in the front-rear direction. Can do. Although not shown, the base 6 is provided with a locking spring that supports the backward movement of the first support shaft 9.

  On one of the left and right sides of the base 6, as one of the components of the back frame device, a pair of left and right swing frames 10 extending in the rearward tilting posture (backward tilting with respect to the vertical line) and extending rearward of the base 6 are shown. The front end of the swing frame 10 is connected to the base 6 by a horizontally long second support shaft 11, and therefore the swing frame 10 can tilt around the second support shaft 11. The left and right swing frames 10 are fixed with screws (not shown) in a substantially box-like intermediate housing 12 having an upward opening shown independently in FIG. The intermediate housing 12 is also a constituent element of the back frame device described in the claims. In this embodiment, the swing frame 10 and the intermediate housing 12 constitute the main frame described in claim 3.

  The middle housing 12 is connected to the lower part of a pair of left and right rear support links 13 by a left and right longitudinal rotation shaft 14, and the upper part of the left and right rear support links 13 is connected to the rear part of the seat outer shell 7 by a left and right longitudinal axis. It is connected. Accordingly, when a person is seated, the seat 2 moves downward while retracting as the front and rear support links 8 and 13 rotate. The seat outer shell 7 is integrally formed with a downward bracket for attaching the support links 8 and 13.

  An upright standing portion 10a is integrally formed at the rear end of the left and right swing frame 10, and a back frame 15 having a substantially square shape in rear view having left and right vertical frame portions and upper and lower horizontal frame portions is formed on the standing portion 10a. It is fixed. At the upper part of the back frame 15, a laterally long portion 15 a is formed extending substantially along the entire length of the backrest 3, and the backrest 3 is fixed to the laterally long portion 15 a (details will be described later). The horizontally long portion 15 a of the back frame 15 is covered with a back cover 16 from the back side.

  In this embodiment, the swing frame 10 and the intermediate housing 12 are light metal products such as aluminum, and the back frame 15 is made of synthetic resin. Of course, the material and processing method of each member can be arbitrarily selected as necessary (for example, a sheet metal product can also be adopted), and the swing frame 10 and the intermediate housing 12 can be integrated, The entire back frame device may be integrated. The back frame 15 can also be called a back column.

  Although not shown, an interlocking member having a front end connected to the first support shaft 9 is disposed inside the base 6, and the rear end of the interlocking member is the second end shown in FIG. The three support shafts 17 are connected to the left and right swing frames 10.

  The front support link 8 and the rear support link 13 are inclined slightly rearward with respect to the vertical line in a side view in a neutral state (basic posture) in which no person is seated. As a result, the seat 2 retreats while being lowered (or slides obliquely backward) with almost no change in the side posture.

  When a person leans against the backrest 3, the backrest 3 tilts backward against the locking spring, and the seat 2 tilts backward by a slight angle while moving backward in conjunction with the back tilt of the backrest 3. For example, a return spring for returning the seat 2 to the base when a person leaves the seat is provided at an appropriate portion such as the inside of the front support link 8. The front support link 8 and the rear support link 13 are examples of seat lowering allowance means.

  As will be described in detail later, the backrest 3 includes a flexible resin inner shell 19, a cushion 20 stretched on the front surface thereof, and a cloth (skin material) 21 covering the cushion 20. The cloth 21 is formed in a bag shape and covers most of the back side of the inner shell 19. The cushion 20 is formed by an insert molding method, and therefore partially surrounds the back side of the inner shell 19.

  The backrest 3 is gently curved in a forward-facing concave shape in plan view in both upper and lower parts. Further, the lower end of the backrest 3 is positioned near the seat 2 in the non-sitting state, and a lumbar support portion 22 protruding forward in a side view is provided at the lower portion of the backrest 3. The lumbar support portion 22 is curved in a forward projecting shape with a gentle curvature.

  The inner shell 19 of the backrest 3 has an upper end fixed to the back frame 15 so as not to be separated. On the other hand, upper bracket portions 23 project rearward from the left and right ends of the lumbar support portion 22 of the inner shell 19, and the upper bracket portion 23 is an arcuate upper link that is loosely curved in a concave shape in a plan view. 24 is connected to a laterally long shaft 25 so as to be relatively rotatable.

  Further, a lower bracket portion 26 protrudes rearward from each of the lower ends of the vertically long center line at the lower end of the inner shell 19, and the front end portion of the lower link 27 extends to the lower bracket portion 26 so as to be a horizontally elongated shaft. 28 is connected to be relatively rotatable. The upper and lower links 24 and 27 are connected to a vertically long main link 29 by a shaft 30 so as to be relatively rotatable. When a person is seated, the main link 29 pivots forward about its lower end, and this causes the lumbar support part 22 of the backrest 3 to move forward greatly. As a result, even if the person sits shallowly, the waist is accurately positioned. Supported.

(2). Forward movement mechanism of lumbar support part Next, an interlocking device in which the lumbar support part 22 moves forward by sitting will be described mainly with reference to FIGS. 4 is a perspective view of members constituting the interlocking device, FIG. 5 is a partially separated plan view of a portion where the interlocking device is disposed, FIG. 6 is a longitudinal side view of the main part, and FIG. 7 is a schematic diagram showing movement. .

  The interlocking device of the present embodiment includes the drive shaft 14 described above, a first interlocking link 32 fixed to the drive shaft 14 by welding, a second interlocking link 33 disposed behind the first interlocking link 32, The main link 29 and the vertical links 24 and 27 described above and the first interlocking link 32 are provided. The drive shaft 14 is rotatably fitted to a bearing portion 34 formed at the front portion of the intermediate housing 12 and is connected to the left and right rear support links 13 so as not to be relatively rotatable.

  An arm body 35 is disposed below the first interlocking link 32. A lower part of the arm body 35 is rotatably supported by the intermediate housing 12 via a rotary damper 36, and a left and right horizontally elongated first interlocking pin 37 is fitted into the upper part of the arm body 35.

  The first interlocking link 32 has left and right side plates and a top plate, and is formed in a substantially U-shaped cross section. The left and right side plates are formed with long slots 38 with rearward openings in which the first interlocking pins 37 are fitted. Has been. Therefore, the first interlocking link 32 and the arm body 35 can rotate integrally.

  The second interlocking link 33 includes a left and right side plate 33a and a top plate 33b, and is formed in a downward opening U-shape. The rear end portion of the left and right side plate 33a is rotated relative to the lumbar support portion 22 by the second pin 39. Connected as possible. In addition, the left and right side plates 33a of the second interlocking link 33 extend forward from the top plate 33b, and the forward extensions of the left and right side plates 33a are formed with a U-shaped bowl-shaped portion 33b that opens in the opposite direction. And the edge part of the said 1st interlocking pin 37 is engage | inserted by this hook-shaped part 33b. The slider 40 made of synthetic resin is fitted into the hook-shaped portion 33 c of the second linkage link 33, and the first linkage pin 37 is fitted into the slider 40. Accordingly, the first interlocking link 32, the second interlocking link 33, and the arm body 35 rotate together.

  The rotary dampers 36 are disposed on both the left and right sides of the arm body 35 and are fitted into the receiving portions 41 of the upward opening formed in the intermediate housing 12. Further, a cover plate 42 for preventing the removal is fixed to the upper surface of the receiving portion 41 with screws. The fixed shaft 36 a of the rotary damper 36 is non-rotatably fitted in a groove 43 formed in the intermediate housing 12, while the rotary shaft 36 b of the rotary damper 36 is fitted below the arm body 35 so as not to be relatively rotatable. The rotary damper 36 uses a viscous fluid so that a large resistance is generated when the arm body 35 is turned over and a small resistance is generated when the arm body 35 is rotated back. .

  The lower end portion of the main link 29 is positioned between the rear portions of the left and right side plates 33a of the second interlocking link 33, and the lower end portion of the main link 29 is connected to the rear portion of the intermediate housing 12 by the second interlocking pin 39. ing. Accordingly, the main link 29 and the second interlocking link 33 rotate around a common axis. A bush 45 is fitted into the third interlocking pin 44.

  In addition, a stopper groove portion 44 that is opened downward is formed in a lower portion of the main link 29 on the front side of the second interlocking pin 39, while a stopper groove portion 44 is formed on the rear portion of the second interlocking link 33. A stopper pin 45 to be fitted is attached. The top plate 33a of the second linkage link 33 is formed with a downward piece 46 cut and raised. A pin 47 is inserted into the downward piece 46 and one side plate 33a, and the pin 47 is inserted through a cylinder. The interlocking spring 48 is fitted. The interlocking spring 48 is a torsion spring in which a load acts in the coil winding direction, and both the one end portion 48a and the other end portion 48b extend backward.

  One end 48 a of the interlocking spring 48 is in contact with the top plate 33 b of the second interlocking link 33 from below, while the other end 48 b of the interlocking spring 48 is in the stopper groove 44 of the main link 29 from above. It is hit. As described above, the upper link 24 is connected to the upper end portion of the main link 29, and the lower link 27 is connected to a vertical middle part of the main link 29.

(3). Description of Movement The movement under the above configuration is shown in FIG. That is, when a person is seated, the front and rear support links 8 and 13 tilt backward, and the seat 2 moves backward while descending. Then, when the drive shaft 14 rotates in conjunction with the rearward tilt of the rear support link 13, the first interlocking link 32 tilts backward, and the rotation of the first interlocking link 32 causes the second interlocking link 33 and the interlocking spring 48 to rotate. To the main link 29, and the main link 29 tilts forward. Accordingly, the posture of the backrest 3 is changed so that the lumbar support portion 22 moves forward. For this reason, even if a person sits shallow, the lumbar support function is exhibited.

  When the seat 2 descends due to the seating, resistance is applied to the descending motion of the seat 2 by the rotary damper 36, so that the seat 2 descends gradually without descending with the stone, and thus the seating comfort. Is excellent.

  Some people sit deeply, and even if they sit shallowly, the degree varies. In the present embodiment, since the main link 29 is rotated forward by the interlocking spring 48, the lumbar support portion 22 of the backrest 3 is not lowered even when the seat 2 is lowered when a person is sitting deeply from the beginning. The interlocking spring 48 escapes and deforms with little or no advance. In addition, when seated shallowly, depending on the sitting position, the lumbar support portion 22 of the backrest 3 may only advance by a dimension smaller than the maximum advance stroke. That is, the difference in the sitting depth is absorbed by the deformation of the interlocking spring 48, and the lumbar support function for the user is exhibited.

  The chair of this embodiment is intended for general adults, and the lumbar support portion 22 has a height that supports the user's lumbar vertebra (particularly the third lumbar vertebra) in a state where the person is seated and the seat 2 is lowered. It is set to be. It is also possible to provide a lock device that kills the function of the interlocking mechanism so that the lumbar support portion 22 does not move forward even when the seat is lowered.

(4). Structure of the backrest Next, the structure of the backrest 3 will be described mainly with reference to FIGS. 8 is a rear view of the inner shell 19, FIG. 9 is a front view of the inner shell 19, FIG. 10A is a side view of the inner shell 19, and FIG. 8B is a state in which the cushion 20 is displayed. 9 is a cross-sectional view taken along the line XB-XB in FIG. 9, and FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG.

  The inner shell 19 is manufactured in a substantially plate shape by an injection molding method made of a synthetic resin such as polypropylene, and the shape thereof is generally a quadrangle when viewed from the front, and a side view (or a longitudinal side view) As seen from the side sectional view, the lumbar support portion 22 is gently curved as a whole so as to protrude most forward. On the other hand, in plan view, it is curved in a forward concave shape at any height position. In addition, the lumbar support portion 22 has the largest degree of curvature in a plan view.

  In the present invention, the lumbar support portion 22 is a curved portion including a vertex protruding forward, and the actual size in this embodiment is about 80 to 100 mm in the vertical direction (specific dimensions are necessary). Can be set arbitrarily according to.) 10 and 11, the inner shell 19 shows a profile in a state before being attached to the back frame device.

  The lumbar support portion 22 has a quasi-rigid structure in which the shape in plan view can be changed (can be changed) depending on the human body pressure, but the shape in side sectional view is hardly deformed. In order to maintain appropriate rigidity, a horizontally long reinforcing rib 50 is provided on the back side of the lumbar support portion 22. The upper bracket portions 23 are formed at the left and right end portions of the lumbar support portion 22 as described above. Since the lumbar support portion 22 is a semi-rigid body, the left and right end portions are supported by the upper links 24. However, the body pressure of the person can be accurately supported, and the cushioning property can be secured by slightly deforming so as to sink backward.

  The lumbar support portion 22 is provided with circular or rectangular window holes 51 in the form of dots. This window hole 51 is mainly used to wrap around the back side when the cushion 20 is insert-molded. As the cushion 20 wraps around the back side of the inner shell 19, the cushion 20 is held in a state where it does not easily fall off with respect to the inner shell 19, and the cloth 21 located on the back side of the inner shell 19 is held tightly. It looks good.

  A portion of the inner shell 19 below the lumbar support portion 22 is a lower deformation allowing portion 53 formed by forming a group of left and right horizontally elongated lower slits 52 vertically and horizontally. The group of the lower slits 52 extends to the left and right end edges of the inner shell 19 as a whole. Therefore, the lower deformation allowing portion 53 can be expanded and contracted (particularly stretched) in the vertical direction at any position on the left and right.

  The lower end of the inner shell 19 that is continuous with the lower deformation allowing portion 53 from below is a lower shape retaining portion 54 having no slit, and the lower retaining portion 54 is formed with the lower bracket portion 26. Due to the presence of the lower shape retaining portion 54, the inner shell 19 (backrest 3) is stably held by the lower link 27. In addition, since the lower bracket portion 26 is located near the left and right middle portion of the inner shell 19, it is extremely easy for the right and left middle portion of the lower deformation allowing portion 53 to extend and deform (extend and contract) in the vertical direction. .

  A certain range of the inner shell 19 that is continuous with the lumbar support portion 22 from above (the range of the vertical width of the same extent as the lumbar support portion 22) is the upper deformation allowing portion 55. The upper deformation allowance portion 55 includes a center deformation allowance portion 56 located at the left and right intermediate portion of the inner shell 19, a side deformation allowance portion 57 located near the left and right ends of the inner shell 19, and the side deformation allowance portion 57 and the center. A substantially rectangular space 58 formed between the deformation permissible portion 56 and the center deformation permissible portion 56 and the side deformation permissible portion 57 are formed with a group of left and right horizontally elongated upper slits 59 in multiple stages. ing. The upper slit 59 has a slot-like shape whose both ends are closed and a groove-like shape which opens in the space 58 are alternately arranged up and down. The space 58 has the same or slightly smaller area as the center deformation allowing portion 56.

  The center deformation allowing portion 56 is a kind of bellows, while the left and right outer ends of the side deformation allowing portion 57 extend in a series. Accordingly, the upper deformation allowance 55 extends the largest at the center deformation allowance 56. Therefore, it is easy to escape so that the center deformation | transformation permission part 56 sinks back with the body pressure of the person who seated.

  A plate-like portion 60 that does not expand and contract is continuous above the upper deformation allowance portion 55 in the inner shell 19, and an attachment portion 61 that overlaps the horizontally long portion 15 a of the back frame 15 at the upper end of the plate-like portion 60. Are formed, and a laterally long rib 62 (see FIGS. 10 and 11) is formed on the back surface of the lower end portion of the attachment portion 61. Further, window holes 51 are also formed in the plate-like portion 60 and the attachment portion 61 in an appropriate arrangement.

  Further, left and right ends of the upper end portion of the plate-like portion 60 are formed with a side opening and a closed slot-like auxiliary slit 63. The presence of the auxiliary slit 63 makes it smooth that the lumbar support portion 22 moves forward when a person is seated. That is, the presence of the auxiliary slit 63 makes it easy for the plate-like portion 60 to bend in a side view with the upper end as the center, and as a result, the lumbar support portion 22 moves forward with ease.

  The auxiliary slit 63 is formed in the inner shell 19 when the inner shell 19 of the backrest 3 is made of a material having no flexibility such as an elastomer, and the forward movement of the lumbar support portion 22 accompanying the seating is smooth. As an invention to solve the problem, that is, to obtain a backrest suitable for the chair described in Patent Document 3, the invention may be an independent claim. The auxiliary slit 63 is an example of a weakening means for the edge of the inner shell 19, and other examples of the weakening means include forming the auxiliary slit in an opening shape, a closed shape, or both, as well as the edge portion of the inner shell 19. It is also possible to reduce the thickness.

  Needless to say, the cushion 20 enters the back side of the inner shell 19 also at the slits 59 and 63 and the space 58 (see FIG. 10B).

  In the above-described configuration, the inner shell 19 is mainly in a state where the lumbar support portion 22 is greatly advanced due to the upper and lower deformation allowing portions 55 and 53 extending and contracting in the vertical direction, and the inner shell 19 is greatly bent in the vertical side view or in the vertical side view. It can be smoothly deformed to a state where it is flattened.

  Further, since the inner shell 19 extends and deforms the largest in the vertical direction at the left and right intermediate portions, the inner shell 19 extends and deforms smoothly in a vertical side view even if the shape around the inner shell 19 does not change. As a result, when human body pressure is applied during locking, the inner shell 19 extends flatly and is deformed to provide good fit. In other words, in this embodiment, it can be said that the inner shell 19 has a hammock structure having a lumbar support function.

(5) Mounting structure of the upper part of the backrest Next, a connecting structure of the upper part of the backrest 3 (inner shell 19) and the back frame 15 will be described with reference to the drawings of FIG. 12A and 12B are views showing the upper part of the back frame 15, FIG. 12A is a rear view, FIG. 12B is a front view, FIG. 13C is a side view, and FIG. 13 is a view taken along line XIII-XIII in FIG. 14 is a sectional view taken along the line XIV-XIV in FIG. 12A. FIG. 15A is a partial front view of the inner shell 19, and FIG. ) Is a cross-sectional view taken along the line B-B, and (C) is a cross-sectional view taken along the line C-C of FIG.

  The horizontally long portion 15a of the back frame 15 has a rib protruding rearward around the periphery, and has a rigid structure as a whole. Then, four receiving seats 65 into which the screws 64 are inserted from the rear are formed on both the left and right sides across the vertically long center line. The front surface of the receiving seat 65 is a substantially square recess 66.

  On the other hand, a portion of the mounting portion 61 of the inner shell 19 corresponding to each receiving seat 65 of the back frame 15 is a bag-like portion 67 that fits into a recess 66 of the receiving seat 65 as clearly shown in FIG. Is formed. The bag-like portion 67 has a bottom plate 67a that overlaps the receiving seat 65, and a nut 69 overlaps the bottom plate 67a. The nut 69 is a horizontally long square (non-circular) and has a projecting portion 69a protruding forward, while a screw insertion hole 70 is provided in the bottom plate 67a of the bag-shaped portion 67.

  The bottom plate 67 a of the bag-like portion 67 in the inner shell 19 is stepped down from the front surface of the inner shell 19, and therefore the location of the bottom plate 67 a is a recess 71 that is recessed from the front surface of the inner shell 19. The bag-like portion 67 is formed with a cover piece 73 that closes the female screw hole 72 of the nut 69 from the front side. The cover piece 73 has a cantilever shape and extends downward, so that it bends and deforms. By bending and deforming the cover piece 73, the nut 69 can be fitted into the recess 71 from below, and the nut 69 is held by the cover piece 73 so as not to be detached.

  The inner shell 19 has a hole for forming the cover piece 73 by pulling out, and this hole is a square screw insertion hole 70. When the nut 69 is fitted into the recess 71, the screw insertion hole 70 is closed with the nut 69, and the female screw hole 72 of the nut 69 is closed with the cover piece 73. Therefore, the cushion 20 does not enter the female screw hole 72 of the nut 69 when the inner shell 19 loaded with the nut 69 is set in the mold and the cushion 20 is stretched by insant molding.

(6). Others Specific examples of the present invention are not limited to those described above, and can be embodied in various ways. For example, when forming a deformation | transformation permission part in an inner shell, the shape and arrangement | positioning of a group of a slit can be changed freely. In addition, the structure and form of the back frame device can be freely changed. When the lumbar support portion is advanced by lowering the seat, the seat lowering allowance means is not limited to that using a link, and for example, one using an inclined slider or one using a slide cylinder can be adopted.

  Further, when the lumbar support portion of the backrest is moved forward by lowering the seat, various configurations such as using a wire can be adopted as the interlocking mechanism. It is also possible to advance the entire backrest by lowering the seat.

(A) is the whole perspective view which looked at the chair concerning an embodiment from the front, and (B) is a partial back view. (A) is the partial perspective view which looked at the chair from back, (B) is a partial side view. It is a perspective view of a partial member which constitutes an interlocking device. It is a perspective view of the member which comprises an interlocking device. It is a partial separation top view of the part by which the interlocking device is arrange | positioned. It is a vertical side view of the principal part. It is a schematic diagram which shows a motion. It is a rear view of an inner shell. It is a front view of an inner shell. (A) is a side view of the inner shell 19, and (B) is a cross-sectional view taken along the line XI-XI in FIG. 9 with the cushion 20 displayed. It is the XI-XI sectional view taken on the line of FIG. It is a figure which shows the upper part of the back frame 15, (A) is a rear view, (B) is a front view, (C) is a side view. FIG. 13 is a sectional view taken along line XIII-XIII in FIG. FIG. 13 is a sectional view taken along line XIV-XIV in FIG. (A) is a partial front view of the inner shell 19, (B) is a sectional view taken along the line BB of (A), and (C) is a sectional view taken along the line CC of (A).

Explanation of symbols

2 seats 3 backrests 6 bases 8 and 13 support links constituting lowering allowance means for seats 10 swing frames constituting main frames of back frame devices 11 intermediate housings constituting main frames of back frame devices 14 drive shafts 15 back frames Back frame 19 constituting the apparatus 19 Back inner shell 20 Cushion 22 Lumber support part 24 Upper link 27 Lower link 29 Main link 32 First interlocking link 33 Second interlocking link 52, 49 Slit 53 Lower deformation permissible part 55 Upper deformation permissible part 58 Space 64 Screw 65 Receiving seat 67 Bag-shaped part 69 Nut 73 Cover piece

Claims (5)

A seat, a backrest formed by placing a cushion on the front surface of the inner shell made of synthetic resin, and a back frame device that supports the backrest from the back side, and the inner shell in the backrest covers the waist of the seated person It has a lumbar support part that can be supported, and the upper part of the inner shell is held by the back frame device with almost no deformation, while the lower end part of the inner shell below the lumbar support part is the back frame. It is connected to the device, and the inner shell is allowed to extend and deform from a form in which the lumbar support part protrudes forward in a side sectional view to a state close to flat,
A chair called
The lumbar support of the inner shell has a quasi-rigid body structure in which the shape in plan view can be easily deformed by the body pressure of the seated person, but the shape in side sectional view is not easily deformed. A slit group is formed on either or both of the upper and lower sides sandwiching the lumbar support part to extend and deform in the vertical direction to enable the lumbar support part to move forward.
Chair. The left and right ends of the lumbar support of the inner shell in the backrest are connected to the back frame device, and the lower end of the inner shell is connected to the left and right intermediate portion or the vicinity thereof to the back frame device,
The chair according to claim 1. The back frame device includes a main frame that is connected to a base disposed below a seat so as to be rearwardly tiltable, a back frame that is disposed to extend upward from the main frame on the back side of the backrest, and an abbreviation of the backrest. It is arranged on the back side of the lower part and has a main link attached to the main frame so that it can rotate forward around the lower end when a person is seated,
While the upper part of the inner shell in the backrest is fixed to the upper end of the back frame,
The left and right end portions of the lumbar support portion of the inner shell in the backrest are connected to the upper link that is connected to the main link so as to be rotatable up and down, and can be relatively rotated in a side view, and the inner shell of the backrest The lower end portion is connected to the lower link that is connected to the main link so as to be relatively rotatable in a side view at a portion below the upper link, and is rotatable relative to the upper link and the lower link. The inner shell is deformed by changing
The chair according to claim 1 or 2. In the inner shell of the backrest, a group of lower slits extends in a state near the full length of the left and right below the lumbar support. Therefore, the portion of the inner shell below the lumbar support is vertically While being allowed to stretch and deform in the direction,
The portion of the inner shell in the backrest that is continuous with the upper end of the lumbar support portion is a deformation-permitting portion having upper slit groups at three portions, the left and right intermediate portions and the left and right end portions, and the side deformation located on the left and right Between the permissible portion and the center deformation permissible portion located in the middle is a space opened in the front and rear,
The chair according to any one of claims 1 to 3. A cushion is stretched on the front surface of the inner shell of the backrest by an insert molding method, and a bag-like portion into which a nut can be inserted from the front surface of the inner shell is formed on the upper portion of the inner shell of the backrest. The upper part is screwed into the nut and fixed to the back frame device with screws,
Further, the bag-like portion of the inner shell is closed by a nut, and a cover piece that covers the female screw hole of the nut is formed on the front side of the inner shell of the bag-like portion.
The chair as described in any one of Claims 1-4.

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