JP2011136039A - Rocking chair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rocking chair keeping the base easy to assemble. <P>SOLUTION: The rocking chair has a base 3, the base 3 is disposed with, as an example, a torsion bar as a rocking spring unit, a cam 40 for applying an initial load to the torsion bar, a handle shaft 41 for movably operating the cam 40, and an arm 37 for transmitting the movement of the cam 40 to the torsion bar. The cam 40 is moved to a position at which the cam member does not abut on the arm 37. Accordingly, the chair is assembled safely and efficiently. Usually, the second cam surface 40b of the cam 40 abuts on the arm 37, and in such a state, the cam 40 is held with a screw fixed to the handle shaft 41 so as not to be moved in a direction reducing the resiliency. Therefore, a minimum load always acts on the torsion bar 34 safely. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rocking chair whose backrest tilts backward against spring means.

  In a rocking chair in which the backrest tilts backward, the back tilt of the backrest is supported by spring means. As the spring means, a coil spring, a torsion bar, a torsion bar coil spring (kick spring) or the like is used. In any case, it is common to provide a resilience adjusting device for adjusting the magnitude of the resistance of the spring means against locking. As an example, the applicant of the present application disclosed in Patent Document 1 a resilience adjusting device having a structure in which a cam member is moved to the left and right by rotating a screw shaft with a handle.

Japanese Patent Application No. 2008-313170

  Now, when a seated person leans on the backrest, if no load is applied to the spring means at the initial stage of the leaning, the spring means deforms from a state where the load is zero. And very dangerous. Therefore, the spring means must be applied with an initial load even when the person is not leaning against the backrest.

  In addition, in a synchronized type chair in which the seat tilts backward / retreats in conjunction with the back tilt of the backrest, the back tilt / retreat motion of the seat is also supported by the spring means, so that the seat can be moved in the non-locking state. The spring means must be loaded so that it does not tilt or retract.

  In any case, in a rocking chair, an initial load (pretension) must be applied to the spring means. Therefore, when assembling the chair, there is a method of assembling the spring means with an initial load applied, but there is a problem that the work is troublesome because the spring force of the spring means is quite strong.

  On the other hand, there is a system in which the cam member is moved by rotating a screw shaft with a handle as an elasticity adjusting device. In this system, the spring member is moved to a position where no load is applied to the spring means. The initial load can be applied. However, in this method, the handle is erroneously returned and rotated in the use state of the chair, and the cam member is moved to a position where no load is applied to the spring means. Therefore, as described above, the backrest is locked when locking. There is a possibility of exhibiting a phenomenon of sudden backward tilt.

  The present invention has been made in view of such a current situation, and an object of the present invention is to provide a rocking chair excellent in assembly workability and safety in use.

  The chair according to the present invention is provided with a spring means for supporting rearward tilting of a backrest on a base provided at an upper end of a leg, and an elastic adjustment device for adjusting an initial elastic force of the spring means. The adjusting device has a screw shaft with a handle that is rotated by a person, and a cam member that moves in the axial direction of the screw shaft by the rotation of the screw shaft, and the spring means is moved by moving the cam member. The initial load applied to is changed.

  And in invention of Claim 1, in the said structure, the said cam member can move to the free position which has not applied the initial load with respect to the said spring means at all, and the initial load is applied to the said spring means. Stopper means for preventing movement from a position to a position where no initial load is applied is provided by retrofitting. The invention of claim 2 is the screw according to claim 1, wherein the stopper means is screwed into the screw shaft from a direction orthogonal to the axis.

  According to a third aspect of the present invention, in the first or second aspect, the spring means is a torsion bar extending in the left-right direction, and the torsion bar is attached with a rotary arm for applying an initial load of torsion. When the cam member moves, the cam member is brought into contact with the arm, and the contact surface between the arm and the cam member is a cam surface inclined with respect to the axis of the screw shaft. The initial turning amount of the torsion bar is changed by changing the initial rotation amount.

  Further, the invention of claim 4 is the invention according to claim 3, wherein the cam surface of the cam member ranges from a completely unloaded state where no load is applied to the torsion bar to an initial load state where a certain amount of load is applied to the torsion bar. And a second cam surface that functions in a range from the initial load state to a maximum load state that imparts the largest load to the torsion bar, with respect to the axis of the screw shaft The angle at which the first cam surface is inclined is set to an angle larger than the angle at which the second cam surface is inclined with respect to the axis of the screw shaft.

  In the present invention, when assembling the chair, the spring means can be gradually and gradually loaded (initial load) by rotating the screw shaft from an unloaded state, so that the assembly of the chair can be performed safely and easily. Yes. After assembly of the chair, the cam means moves only in the area where the load is applied to the spring means by the stopper means, preventing the phenomenon that the backrest suddenly tilts when locking, ensuring safety. it can.

  Various stopper means can be employed. However, when a screw is employed and screwed into the screw shaft as in claim 2, the cam member can be reliably stopped and moved with a very simple structure.

  Now, it is possible to make the cam surface of the cam member have the same profile over the entire length, but in the configuration in which the cam member moves to a position where no load is applied to the spring means, the moving stroke of the cam member becomes large. There is a risk that the left and right width dimensions of the base must be increased due to the left and right movement stroke of the cam member. In this regard, when the invention of claim 4 is adopted, the cam member can change the initial load proportionally in a normal use state while reducing the moving distance from the no-load state to the initial load state. Therefore, it becomes possible to make the width dimension of the base as small as possible without impairing the function of smoothly adjusting the elasticity of the spring means.

It is an external view of the chair which concerns on embodiment, (A) is a perspective view, (B) is a side view. FIG. FIG. (A) is the whole perspective view of the part centering on the base, (B) is the whole separation perspective view. It is the isolation | separation perspective view centering on the locking mechanism and the elasticity adjusting device. It is an isolation | separation perspective view of the part centering on the base. It is the isolation | separation perspective view centering on the locking mechanism and the elasticity adjusting device. (A) is the front view of a base part, (B) is the perspective view which looked at the base part from the downward direction. (A) is a partial bottom view of the base portion in the initial load state, and (B) is a partial bottom view in the maximum load state. (A) is the partial bottom view of the base in an unloaded state, (B) is the perspective view which looked at the base part in an unloaded state from the bottom. It is a figure which shows the attachment structure of a back frame, (A) (C) is a separated view, (B) is a fragmentary perspective view of a central axis. FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a swivel chair frequently used for office work. In the following description (and claims), the words “front and back” and “left and right” are used to specify the direction, and this is based on a normal sitting state.

(1). Outline of Chair First, an outline of a chair will be described with reference to FIGS. As shown in FIGS. 1 and 2, the chair includes, as main elements, a leg device 1 having a leg column 2, a base 3 fixed to the upper end of the leg column 2, a seat 4 disposed above the base 3, and a backrest 5. The back frame 8 is provided.

  The leg device 1 includes a plurality of branch legs extending radially, and a caster is provided at the tip of each branch leg. In the figure, only a part of the limbs is displayed. The leg support 2 uses a gas cylinder that can be expanded and contracted. The chair also has a back frame 7 that extends in the front-rear direction on both the left and right sides of the base 3, and a back column 7 a that extends upward is integrally provided at the rear of the back frame 7. The back frame 8 is fixed with screws. A mesh-like sheet material 9 is stretched on the back frame 8. Therefore, in this embodiment, the backrest 5 is constituted by the back frame 8 and the sheet material 9.

  As shown in FIG. 4 (B), the back frame 7 is connected to the base 3 by a horizontally elongated central shaft 10 so as to tilt backward with the front end portion as the center. The central shaft 10 uses a hollow cylinder, and a torsion bar as an example of a spring means is built in the center shaft 10, and the backrest 5 tilts backward against the elasticity of the torsion bar (details will be described later). ).

  The member indicated by reference numeral 11 in FIG. 3 is a lumbar support, and the member indicated by reference numeral 12 in FIG. 3 is a rear link for relatively moving the lumbar support 11 backward during locking. The lumbar support 11 is attached to the upper end of the rear link 12, and at the time of locking, the lumbar support 11 is retracted and the tension on the sheet material 9 is weakened (or the sheet material 9 is loosened).

  As shown in FIG. 2, the seat 4 has a structure in which a cushion material 14 is stretched on a resin inner shell 13, and the inner shell 13 is fixed to a resin outer shell 15 disposed therebelow. The outer shell 15 is attached to a seat receiving member 16 having a substantially square shape in plan view disposed below the outer shell 15 so that the front and rear positions can be adjusted.

  As can be understood from FIG. 5, a pair of left and right support cylinders 18 project from the left and right outwards on the front side surface of the base 3, and a front link 19 is rotatably fitted in the support cylinder 18. On the other hand, as shown in FIG. 3, for example, a downward front bearing portion 20 is formed at the front end portion of the seat receiving member 16, and the front link 19 is connected to the front bearing portion 20 by a front pin 21.

  As shown in FIG. 3, a rear bearing portion 22 projects downward from the rear portion of the seat receiving member 16, and a lower end of the rear bearing portion 22 and the back frame 7 are connected by a rear pin 23. The rear pin 23 is slidably fitted into a guide long hole 24 formed on the inner surface of the back frame 7 via a square slider 25. While the front link 19 tilts backward, the rear pin 23 slides through the guide slot 24 of the back frame 7, thereby allowing the back frame 7 to tilt backward. The front end of the rear link 12 is connected to the seat receiving member 16 by a pin 21.

(2). Outline of structure of base and its peripheral portion Next, an outline of the base 3 and its peripheral members will be described with reference to FIG. 6 and subsequent drawings. The base 3 is a metal molded product such as an aluminum die cast. For example, as shown in FIG. 5, the base 3 is generally a rectangle that is long in the front-rear direction in a plan view, and is generally open upward except for its front part. It has become. A leg support 2 is fitted to the rear end of the base 3.

  A bearing recess 28 whose left and right sides are opened upward is formed in a slightly forward portion of the base 3, and the central shaft 10 is fitted in the bearing recess 28. The central shaft 10 is rotatably fitted to the base 3 via a vertically separated resin bush 29 (see FIG. 7 in particular). The bush 29 is held by a pressing plate 31 (see FIG. 6) so that it cannot be separated vertically. The pressing plate 31 is fixed to the base 3 with screws.

  For example, as can be understood from FIG. 5, the base portion of the left and right central shaft 10 is fixed by welding to a center bracket 32 having a substantially upward U-shape when viewed from the front. That is, the base portion of the left and right central shaft 10 is welded to the side plate 32 a of the center bracket 32. Accordingly, the left and right center shafts 10 rotate (rotate) together with the center bracket 32.

  As shown in FIG. 7, a torsion bar 34 is arranged inside the central shaft 10 (in FIG. 7, the torsion bar 34 is drawn out and displayed). The torsion bar 34 has a prismatic shape as a whole by bundling four unit bars.

  The central shaft 10 is manufactured from a pipe having an inner diameter larger than the circumscribed circle of the torsion bar 34, and a square holding portion 35 (see FIG. 5) is fitted or crushed at the outer end thereof. An end portion of the torsion bar 34 is fitted into the holding portion 35 so as not to be relatively rotatable. An auxiliary bracket 36 extending rearward is fixed to the outer end portion of the central shaft 10 by welding, and the auxiliary bracket 36 is fixed to the front end portion of the back frame 7 (details will be described later).

  For example, as shown in FIG. 7, a portion 37 of the torsion bar 34 that enters the center bracket 32 is fitted with an elastic adjustment arm 37 that extends forward so as not to rotate relative to the base 3. It protrudes forward from the provided through hole 38. For example, as shown in FIG. 8, a downward opening recess 39 is formed in the front portion of the base 3, and a cam member 40 for adjusting elasticity is disposed in the downward opening recess 39.

  The cam member 40 contacts the arm 37 from above, and when the cam member 40 moves left and right, the arm 37 rotates up and down, and the initial load (pretension) on the torsion bar 34 changes. The arm 37 is made of metal. The arm 37 is an example of a load operating body that causes the movement of the cam member 40 to act on the torsion bar 34.

  A left and right handle shaft (screw shaft) 41 extending in parallel with the torsion bar 34 is inserted into the cam member 40, and the handle shaft 41 passes through the support cylinder 18 of the base 3. One end portion (outer end portion) of the handle shaft 41 protrudes outward from the right support cylinder 18, and a handle (pick) 42 is fixed to the protruding end portion. For example, as shown in FIG. 4B, the base 3 is provided with an upper cover 43 and a lower cover 44. The upper cover 43 is a front and rear separation system.

(3). Locking Elasticity Adjusting Mechanism Next, details of the elastic adjusting device composed of the arm 37, the cam member 40, etc. will be described. Although not clearly shown in the drawing, as can be understood from FIG. 7, the central shaft 10 has an inward end portion 10 a that enters the center bracket 32, and the ring body 45 is fitted into the inward end portion. ing. The arm 37 is provided with an overhanging portion 37 a that overlaps the ring 45 from above. For this reason, it is possible to prevent a bending load from acting on the torsion bar 44.

  As described above, the cam member 40 overlaps the arm 48 from above. Accordingly, the arm 48 and the cam member 40 have contact surfaces that overlap each other. As can be understood from FIG. 8, the cam member 40 has a first inclined surface with respect to the axis of the handle shaft 41 in the front view. A cam surface 40a and a second cam surface 40b are formed. Both cam surfaces 40a and 40b are inclined so as to approach the handle shaft 41 as they approach the handle 42, and the inclination angle of the first cam surface 40a is larger than the inclination angle of the second cam surface 40a.

  The first cam surface 40a is used when the chair is assembled or disassembled, and the second cam surface 40b is used when the chair is used. The contact surface (cam surface) of the arm 37 is set to be in close contact with the second cam surface 40 b of the cam member 40. The cam surfaces 40 a, 40 b, and 37 b of the cam member 40 and the arm 37 may be inclined so as to approach the axis of the handle shaft 41 as the distance from the handle 42 increases.

  The cam member 40 is made of resin or metal, and a handle shaft (screw shaft) 51 is inserted through the cam member 40. Although not shown, a nut is non-rotatably fitted into the cam member 40, and the male thread portion of the handle shaft 41 is screwed into the nut (note that the position of the nut can be arbitrarily set, It is also possible to fit a plurality of nuts.) The handle shaft 41 is held in a state in which the cam member 40 comes into contact with the arm 37 from one direction (right direction) so that the handle shaft 41 can only rotate.

  Accordingly, when the handle shaft 41 is rotated by being gripped by the knob 42, the cam member 40 moves left and right. As shown in FIG. 9B, when the cam member 40 moves to a position where the load on the torsion bar 34 is maximized, the cam member 40 abuts against the inner surface of the base 3 and further movement is restricted.

  For example, as shown in FIGS. 9 and 10, the cam member 40 is movable in a region where the second cam surface 40 b abuts on the arm 37, and the first cam surface 40 a It is possible to move to a region facing the arm 37.

  As described above, in the normal use state, the cam member 40 is used in a region where the second cam surface 40 b abuts on the arm 37. That is, even when the arm 37 is in contact with the end portion of the second cam surface 40b close to the first cam surface 40a, the torsion bar 34 is in an initial load state in which a load is applied. The initial elastic force is stored in the torsion bar 34, but the elastic restoring force in the initial load state is strong enough that the backrest 5 does not tilt backward rapidly even if the seated person leans on the backrest 5. Is set.

  Therefore, for example, as shown in FIG. 9, the cam member 40 moves to the other end portion (inner end portion) of the handle shaft 41 so as not to be removed from the state in which the second cam surface 40 b is in contact with the arm 37. Screws 46 are screwed and fixed as stopper means for regulating the above. Thus, even if a person rotates the handle shaft 41 so as to weaken the elasticity of the torsion bar 34, the second cam surface 40b of the cam member 40 does not come off the arm 37. As a result, safety is ensured.

  On the other hand, the assembly of the chair is performed with the screws 46 removed. That is, as shown in FIG. 9, the handle shaft 41 is screwed in with the cam member 40 being moved to the left end. Then, the arm 37 enters a load state in which the first cam surface 40a abuts from a no-load state, and further enters a load state in which the second cam surface 40b of the cam member 40 abuts. When the cam member 40 moves to a state where the second cam surface 40b is in contact with the arm 37, the screw 45 is screwed into the handle shaft 41.

  As described above, since the handle shaft 41 and the cam member 40 can be mounted in a no-load state in which no initial load is applied to the torsion bar 34, the assembly of the chair can be performed easily, and the use state is as described above. Safety is also ensured. If the inclination angle of the first cam surface 40a is set to be larger than the inclination angle of the second cam surface 40b as in the present embodiment, no load is applied while the movement distance of the cam member 40 is made as small as possible. Since the state can be shifted to the load state, the lateral width of the base 3 can be made as small as possible, and the rotation speed of the handle shaft 41 can be suppressed when the handle shaft 41 and the cam member 40 are set. Decomposition is performed in the reverse procedure.

  Now, when the arm 37 rotates, the relative posture between the contact surface 37b and the upper surface of the base 3 changes. Therefore, when the cam member 40 merely moves left and right without changing the posture in side view, the arm 37 and the cam member 40 are in surface contact only when they are at a specific angle. At other angles, both are in line contact or point contact.

  On the other hand, in the present embodiment, the cam member 40 is rotated about the axis of the handle shaft 41, and therefore, the cam surface 40a of the cam member 40 regardless of the rotation angle of the arm 37. , 40b and the contact surface 37b of the arm 37 are maintained in a surface contact state. For this reason, even if the cam member 40 is made of resin, high durability can be ensured.

  For example, as shown in FIG. 7, the upper end surface of the cam member 40 is an arcuate surface 40 c extending around the axis of the handle shaft 51, while the upper inner surface of the downward opening recess 39 in the base 3 is the cam member 40. Therefore, the cam member 40 is supported by the base 3 in a wide area regardless of the rotation posture thereof, and therefore, a large load acting via the arm 37 is accurately supported. it can. Further, since no bending force is applied to the handle shaft 41, the handle shaft 41 and the cam member 40 are not twisted. Therefore, the handle shaft 41 can be rotated easily. These are one of the advantages of this embodiment.

(4). Locking mechanism / elevating / lowering mechanism Next, the tilt control mechanism of the backrest 5 and the elevating / lowering mechanism of the seat will be briefly described. For example, as shown in FIG. 6, a block-shaped first lock body 48 is fixed to the center bracket 32 with screws, and left and right horizontally long lock grooves 49 are formed in multiple stages on the rear surface of the first lock body 48. Yes.

  On the rear side of the first lock body 48, a second lock body 50 that is fitted in and removed from the lock groove 49 of the first lock body 48 by horizontally turning is disposed. The second lock body 50 has a form extending substantially in the left-right direction in plan view, and is fitted into a boss body 51 provided on the base 3 so as to horizontally rotate around one end (right end) thereof. The backrest 5 is fixed at an angle when the second lock body 50 is selectively fitted in the arbitrary lock groove 49 of the first lock body 48 or the second lock body 50 is detached from the first lock body 48. Or can be freely tilted backward.

  A rotor 52 is rotatably fitted to the boss body 51 of the base 3. A coil-type torsion spring 53 is fitted into the rotor 52, and the second lock body 50 is urged by the coil-type torsion spring 53 in a direction to release from the first lock body 49. The rotation control of the second lock body 50 is performed by pulling the lock wire 56. The pulling operation of the lock wire 56 is transmitted to the second lock body 50 via the control device 55. That is, by pulling the lock wire 56, the second lock body 50 is alternately switched between a lock posture in which the first lock body 49 can be engaged and a free posture in which the second lock body 50 cannot be engaged. The lock wire 56 is connected to a lever (not shown) provided on the right side surface of the outer shell 15.

  As shown in FIG. 5, the lifting operation mechanism includes a first lever 57 that pushes down the push valve of the leg column 2, and a second lever 58 that rotates the first lever 57. Both levers 57 and 58 are rotatably attached to the base 3. The second lever 58 has a substantially triangular shape when viewed from the side, and an elevating wire 59 is locked to the upper end.

  When the elevating lever 59 is pulled, the second lever 59 is rotated, and then the first lever 57 is rotated downward by the pressing action of the second lever 58, thereby pushing down the push valve of the leg column 2. The lifting wire 59 is also connected to a lever (not shown) provided on the right side surface of the outer shell 15.

(5). Mounting Structure of Back Frame Next, the mounting structure of the back frame 7 will be described with reference to FIG. As described above, the auxiliary bracket 36 is fixed to the central shaft 10, and the back frame 7 is fixed to the auxiliary bracket 36.

  While the auxiliary bracket 36 has a U-shape when viewed from the front, a block-shaped protrusion 61 that fits inside the auxiliary bracket 36 is formed on the inner surface of the back frame 7. Therefore, the protrusion 61 is surrounded by the three grooves 62. A portion of the back frame 7 below the protrusion 61 is a notch 63 into which the auxiliary bracket 36 is fitted.

  The front end of the back frame 7 has an arc shape when viewed from the side, and the notch 63 is formed behind the arc-shaped portion. Accordingly, the back frame 7 cannot be fitted into the auxiliary bracket 36 simply by moving it from the top to the bottom, and as shown by O2, the end of the central shaft 10 is first placed in the back frame 7 in the state of being raised upward. The auxiliary bracket 36 and the projecting portion 61 can be fitted together by an operation of fitting into the front end portion and then tilting the back frame 7 into a predetermined posture.

  The auxiliary bracket 36 is fixed to the protrusion 61 with a bolt 64 and a nut 65. That is, a nut holding groove 66 that opens inward in the protrusion 61 is formed, and the bolt 64 is screwed into the nut 65 fitted in the nut holding groove 66, thereby fixing the auxiliary bracket 36 to the protrusion 61.

  Now, fixing the back frame 7 to the auxiliary bracket 36 of the central shaft 10 has been conventionally performed. However, if the back frame 7 is simply overlapped with the auxiliary bracket 36 and fastened with bolts, the positioning of the back frame 7 can be performed. In addition to being troublesome, the bolts must be screwed in while maintaining the posture of the back frame 7, and the work is troublesome.

  In contrast, in the present embodiment, the left and right positions of the back frame 7 are accurately fixed by fitting the projection 61 and the auxiliary bracket 36 together, and when the auxiliary bracket 36 is fitted into the projection 61, the back frame is fixed. 7 is held so that it cannot be pulled out upward, so that it is not necessary to hold the back frame 7 by hand when the bolt 64 is rotated. For this reason, the assembly work can be easily performed.

(6) Supplementary explanation (Part 1)
Next, the configuration of the embodiment will be supplementarily described. As shown in FIG. 3, the lower end of the rear bearing portion 22 of the seat receiving member 16 is provided with a cover piece 22b which is located on the outer surface and protrudes toward the front, and the cover piece 22b is used to The guide slot 24 is covered from the outside. For this reason, even if a person tries to insert a finger into the guide slot 24, it is possible to prevent the finger from being pinched.

  As clearly shown in FIG. 12C, the upper surface of the guide elongated hole 24 in the back frame 7 is curved upwardly concave in a side view, and the upper bush 72 fitted into the guide elongated hole 24 also has an upper inner surface in a side view. The lower bushing is also fitted in the guide slot 24 (not shown in the figure). For this reason, it is possible to prevent the square slider 25 from rattling during locking. This is due to the following reason.

  The square slider 25 moves relative to the back frame 7 in the front-rear direction at the time of locking, but the locus of the contact point between the upper surface of the square slider 25 and the guide long hole 24 at the time of locking is curved upwardly in a side view. For this reason, the rectangular slider 25 moves relative to each other while changing its posture in a side view. However, if the upper surface of the guide elongated hole 24 is a straight line in a side view, the guide length is changed to allow a change in the posture of the rectangular slider 25. The upper and lower inner width dimensions of the hole 24 must be increased, so that play can occur between the square slider 25 and the back frame 7, and the back frame 7 is easily rattled, and the seat 4 is thereafter Since the portion is supported by the back frame 7, the seat 4 is also easily rattled.

  On the other hand, when the upper inner surface 24a of the guide elongated hole 24 is curved as in the present embodiment, the rectangular slider 25 moves relative to the upper inner surface 24a of the guide elongated hole 24 in a state of surface contact. Almost no play is required between the guide slot 24 and the square slider 25. As a result, the back frame 7 can be prevented from rattling.

  The front end portion of the rear link 12 is connected to the rear portion of the seat receiving member 16 by a pin 12 '. For this reason, a hole 16a into which the pin 12 'is fitted is provided in the rear portion of the seat receiving member 16. The pin 12 'has a tapped hole passing through its axis, and is held so that it cannot be removed by screwing a screw inserted through the seat receiving member 16 from above into the tapped hole. In this case, the pin 12 'needs to be fitted into the seat receiving member 16 in a state in which the pin hole is held in such a manner that the tap hole faces in the vertical direction.

  Therefore, by forming a pair of inclined surfaces 12 at the tip of the pin 12 ′, the tip of the pin 12 ′ is formed as a wedge-shaped tip 12 ″, while at the back of the pin hole 16 a in the seat receiving member 16. A fitting groove into which the wedge-shaped tip portion 12 ″ fits exactly is formed. Accordingly, the pin 12 'can be inserted into the pin hole 16a only when the tap hole is in the vertical orientation, and the posture can be accurately adjusted.

(7) Supplementary explanation (Part 2)
As shown in FIGS. 12A and 12B (see also FIG. 3), the rear portion of the rear link 12 is a column portion 12a extending upward, and a ramp support 12c is attached to the column portion 12a via a holder 12b '. The lumbar support 12c supports the sheet material 9 (the lumbar support 12c has a foot portion 12c ', and the foot portion 12c' is provided in the space 12b provided in the holder 12b '. ″ Is inserted in.)

  Accordingly, when the lumbar support 12c is moved up and down, the height of the portion of the seat material 9 that protrudes most forward in the side view changes, and then the height that supports the seated person from behind can be changed (the rear link when locked). 12 rotates, the lumbar support 12c moves backward relative to the back frame 7, and as a result, the tension of the sheet material 9 is loosened.)

  This type of lumbar support function is disclosed in Japanese Patent Application Laid-Open No. 2008-295515 by the present applicant. In the embodiment of this publication, a concavo-convex portion having a waveform in a side view is formed on the column portion 12 of the rear link 12, and the lumbar support is moved up and down along the concavo-convex portion. The present embodiment is an improvement over this earlier application. That is, in the prior application publication, when the lumbar support 12c is raised and lowered, the lumbar support 12c moves in the front-rear direction. Therefore, if the sheet material 9 is strongly stretched, it may be difficult to raise and lower the lumbar support 12c. .

  On the other hand, in the present embodiment, a plurality of rectangular engagement holes 12a ′ are provided in the column 12c of the rear link 12 in the vertical direction, and the engagement protrusions 71 provided on the foot 12c ′ of the lumbar support 12c are engaged. It is engaged with the hole 12a '. In this embodiment, since the lumbar support 12c moves up and down in contact with the front end surface of the support column 12a, the lumbar support 12c moves up and down without moving back and forth, and the engagement protrusion 71 engages with the engagement hole 12a ′. Therefore, the raising / lowering operation of the lumbar support 12c can be easily performed with a light force. It is also possible to provide an engaging projection on the support column 12a and provide an engaging hole on the foot 12c '.

  Further, as a preferred modification of the present embodiment, as shown by a one-dot chain line in FIG. 12B, the front end surface of the support column portion 12a and the line of the engagement holes 12a ′ are curved in a concave shape in a front view. Is possible. Thereby, the vertical stroke of the vertex of the sheet | seat material 9 can be enlarged rather than the stroke of the vertical motion of the lumbar support 12c. That is, the range (up / down stroke) in which the height of the pressing position of the sheet material 9 can be adjusted can be made larger than the up / down stroke of the lumbar support 12c. This is due to the following reason.

  Now, the lumbar support 12c is curved in a forwardly convex shape in a side view, and when the front end of the column portion 12a is a straight line, the vertex portion P0 abuts against the sheet material 9 regardless of the height position. For this reason, the stroke in which the apex of the sheet material 9 changes up and down is the same as the up-and-down stroke of the lumbar support 12c.

  On the other hand, when a modified example is adopted, the lumbar support 12c moves up and down and changes its posture in side view. That is, the lumbar support 12c has its apex portion P0 in contact with the sheet material 9 at the upper and lower intermediate height positions, but when the lumbar support 12c descends from the intermediate height position, the lumbar support 12c has a lower end portion as shown by a dotted line b. The end is inclined so as to protrude forward, and for this reason, the position Pb in contact with the sheet material 9 shifts below the apex portion P0. Accordingly, the sheet material 9 is pushed from behind so that the lower part is the foremost than when the lumbar support 12c is translated.

  When the lumbar support 12c rises from the intermediate height position, as shown by the dotted line a, the lumbar support 12c is inclined so that its upper end protrudes toward the front, and for this reason, the position Pb that contacts the sheet material 9 Shifts below the vertex P0. Accordingly, the sheet material 9 is pushed from behind so that the upper part is the foremost than when the lumbar support 12c is translated.

  After all, in the modified example, the vertical movement of the lumbar support 12c can be amplified and transmitted to the sheet material 9. Even if the lumbar support 12c is inclined, it is preferable to be able to hold the posture firmly. This point can be dealt with, for example, by providing two engaging protrusions 71 on the foot 12c ′ of the lumbar support 12c and engaging the two engaging protrusions 71 with the two engaging holes 12a ′. it can. The posture can be maintained by bringing the lumbar support 12c and the column 12a into surface contact.

  Needless to say, this modification can also be applied to a structure in which a chevron-shaped uneven portion is formed on a support portion as described in JP-A-2008-295515. Further, the lumbar support 12c may be directly attached to the support column 12a without using the holder 12b.

(8). Others The present invention can be embodied in various ways other than the above embodiment. For example, the above embodiment is applied to a type in which the seat is tilted backward while being synchronized with the backrest, but it is needless to say that the seat can be applied to a type in which only the backrest is tilted backward. Needless to say, it can also be applied to fixed chairs such as theater chairs.

  Various spring means such as a coil spring and a leaf spring can be used. The form of the cam member can also be changed as necessary. Further, the cam member does not necessarily need to contact the arm. For example, a method of changing the elasticity of the spring means by moving the wedge member with the cam member is also possible. It can be adopted. The stopper means is not necessarily provided on the screw shaft, and may be provided on another member such as a base.

  The present invention is useful when applied to a chair. Therefore, it can be used industrially.

1 leg device 3 base 4 seat 5 backrest 7 back frame 10 central shaft 34 torsion bar as an example of spring means 37 arm as an example of load acting body 40 cam member 40a first cam surface 40a
40b Second cam surface 40b
41 Handle shaft 42 Handle (grip: grip)
46 Screws as an example of stopper means

Claims (4)

The base provided at the upper end of the leg is provided with spring means for supporting the back tilt of the backrest and an elastic adjustment device for adjusting the initial elastic force of the spring means, and the elastic adjustment device is rotated by a person. It has a screw shaft with a handle to be operated and a cam member that moves in the axial direction of the screw shaft by the rotation of the screw shaft, and the initial load applied to the spring means is changed by moving the cam member. The configuration is designed to be
The cam member is movable to a free position where no initial load is applied to the spring means, and is moved from a position where the initial load is not applied to the spring means to a position where no initial load is applied. Stopper means to prevent this is provided by retrofitting,
Rocking chair. The stopper means is a screw that is screwed into the screw shaft from a direction orthogonal to the axis.
The rocking chair according to claim 1. The spring means is a torsion bar extending in the left-right direction, and a rotary arm for applying an initial load of torsion is attached to the torsion bar, and the cam member is in contact with the arm. Since the contact surface between the arm and the cam member is a cam surface inclined with respect to the axis of the screw shaft, when the cam member moves, the initial rotation amount of the arm changes and the initial load on the torsion bar is increased. Is changing,
The rocking chair according to claim 1 or 2. The cam surface of the cam member has a first cam surface that functions in a range from a complete no-load state in which no load is applied to the torsion bar to an initial load state in which a certain amount of load is applied to the torsion bar; and the initial load state And a second cam surface that functions in a range from a maximum load state that gives the largest load to the torsion bar, and an angle at which the first cam surface is inclined with respect to the axis of the screw shaft. Is set to an angle larger than the angle at which the second cam surface is inclined with respect to the axis of
The rocking chair according to claim 3.

Images