JP2008194125A - Armrest device in chair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an armrest device in a chair in which an armrest base plate can be moved back and forth stably and smoothly and assembled easily with parts reduced in number. <P>SOLUTION: The armrest base plate 31 is mounted on the upper end of an armrest support rod 14. An engagement portion 48 of a support block 46 provided on the upper end of the armrest support rod 14 engages in an oblong hole 35 in the cross direction provided on the armrest base plate 31, and the armrest base plate 31 is put between the wider portion 49 of the support block 46 and the upper surface of the armrest support rod 14. A plurality of recesses 41 are arranged in the cross direction and provided on the side face of a projection 40 provided on the armrest base plate 31 so as to be parallel with the side edge of the oblong hole 35, and the distal end of an elastic tongue 61 provided on the side face of the wider portion 49 in the support block 46 is brought into press contact with the side face with the recesses 41 in the projection 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an armrest device for a chair that can move the armrest in the front-rear direction.

  Some high-grade office chairs are provided with a seat plate height adjustment mechanism and a back plate reclining mechanism, as well as an armrest device that allows the armrest to move in the front-rear direction.

  As a conventional example of this type of armrest device, for example, there is one described in Patent Document 1 or 2 below.

Each of these is provided with a long hole facing in the front-rear direction on the armrest substrate, and a plurality of recesses arranged in the front-rear direction on both side edges of the long hole, and provided at the upper end of the armrest support rod that supports the armrest. The support body is provided with an elastic body that presses against both side edges of the long hole, and the armrest substrate can move in the front-rear direction with respect to the armrest support rod, and the elastic body elastically engages with each recess. Thus, a moderation feeling is imparted to the back and forth movement of the armrest substrate.
JP 2005-2111245 A JP 2002-51871 A

  However, in both of Patent Documents 1 and 2, a plurality of recesses are provided on the side surface of the long hole for guiding the back and forth movement of the armrest substrate, and a means for imparting a sense of moderation is provided in the long hole. The back and forth movement of the armrest substrate becomes unsmooth.

  Moreover, what is described in patent document 1 arrange | positions a pair of engaging pin which faces an up-down direction on the both sides | surfaces of the elastic body provided in the support body, and press-contacts them to the both-sides edge of a long hole. As a result, the number of parts increases and the assembly work becomes complicated.

  In the device described in Patent Document 2, the elastic body is formed by a pair of left and right arcuate members and held by the elbow rest bracket, but the rigidity and durability of the arcuate member is maintained. However, it is necessary to pay attention to the selection of the material and the specification of the shape.

  The present invention has been made in view of the above-mentioned problems of the prior art, and the armrest board can be moved back and forth stably and smoothly, and can be easily assembled with a small number of parts. The object is to provide an armrest device for a chair.

According to the present invention, the above problem is solved as follows.
(1) On the upper end of the armrest support rod supported so as to stand up from the side of the seat, an armrest substrate whose upper surface is covered by an armrest pad is placed, and in the long hole facing the front-rear direction provided on this armrest substrate, A fitting portion having the same width as the left and right width of the long hole in the support block provided at the upper end of the armrest support rod is fitted, and the widened portion provided at the upper end of the fitting portion in the support block and the armrest support rod The armrest substrate is mounted on the armrest support rod so that the armrest substrate can be slid in the front-rear direction by sandwiching the armrest substrate from above and below, and parallel to the side edge of the long hole. A plurality of recesses are arranged side by side in the front-rear direction on the side surface of the protruding piece, and the tip portion of the elastic tongue piece provided on the side surface of the widened portion in the support block is brought into pressure contact with the side surface having the recess in the protruding piece, Moderation for back and forth movement of the armrest substrate The so as to grant.

  (2) In the above item (1), a pair of projecting pieces are provided symmetrically on both sides of the elongated hole in the armrest substrate, and are pressed against the side surfaces of the projecting pieces on both side surfaces of the widened portion of the support block. A pair of elastic tongues is provided symmetrically.

  (3) In the above item (1) or (2), the support block can be rotated about an axis orthogonal to the upper surface of the armrest support rod, whereby the armrest substrate is moved in the front-rear direction with respect to the armrest support rod. Are slidable in the left and right directions and are rotatable in the left-right direction.

  (4) In any one of the above items (1) to (3), when the armrest substrate is moved forward between the upper surface of the armrest support rod and the lower surface of the armrest substrate, the long hole of the armrest substrate faces downward. A shielding plate is provided to prevent exposure.

According to the present invention, the following effects can be achieved.
According to the first aspect of the present invention, the longitudinally moving guide means of the armrest substrate composed of the long hole provided in the armrest substrate and the fitting portion in the support block, and the projecting piece provided with a plurality of recesses arranged side by side on the side surface Since the moderation feeling imparting means comprising the elastic tongue piece provided on the side surface of the widened portion in the support block is provided separately from each other, the armrest substrate can be moved back and forth stably and smoothly, Since the projecting piece can be integrally formed with the armrest substrate and the elastic tongue piece can be integrally formed with the support block, the number of parts can be reduced and the assembly can be easily performed.

  According to the invention of claim 2, since the projection piece and the elastic tongue piece are respectively provided in a pair so as to be symmetric with respect to the elongated hole in the armrest substrate, the armrest substrate is provided with a good balance between left and right, It can be moved back and forth stably and smoothly.

  According to invention of Claim 3, an armrest board | substrate can be rotated to the left-right direction smoothly with sufficient balance in a stable manner.

  According to the invention of claim 4, when the armrest substrate is moved forward, the front part of the long hole of the armrest substrate is closed by the shielding plate, so that fingers of the hand etc. are not sandwiched in the long hole, Moreover, since the long hole is not exposed to the outside, the appearance is good.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a chair provided with an embodiment of the armrest device of the present invention, and FIG. 2 is a side view of the same.
This chair includes a pillar 3 standing upright from the center of five radial rods 2 provided with casters 1 at the tip, a support base 4 provided at the upper end of the pillar 3, and A seat 6 supported via a support link 5 above the support base 4, a backrest 8 that is pivotally attached to the support base 4 with a shaft 7 facing in the left-right direction, and can be tilted backward, It has an armrest device 9 that stands up from both sides (sometimes only one).

3 to 8 show details of the armrest device 9.
The armrest device 9 includes an armrest support cylinder 11 that is configured to stand in a slightly forward tilted posture from the side of the seat 6 by fixing a bracket 10 provided on the inner surface of the lower end portion to the lower surface of the side portion of the seat 6, An intermediate cylinder 12 fitted so as to be in contact with the inner surface of the armrest support cylinder 11 and a cylindrical armrest support rod which supports the armrest 13 and is fitted in the intermediate cylinder 12 so as to be slidable in the vertical direction. 14 and a height adjusting device 15 for adjusting the height of the armrest support rod 14 with respect to the armrest support cylinder 11.

  The armrest support cylinder 11, the intermediate cylinder 12, and the armrest support rod 14 have an elliptical cross section in which the long axis facing the front-rear direction is slightly longer than the short axis facing the left-right direction. It is good.

  The intermediate cylinder 12 is formed by facing and joining halved pieces 12A and 12B divided into left and right parts. At the four corners of the opposing surfaces of the two halved pieces 12A and 12B, there are provided positioning concave portions 16 and convex portions 17 which are fitted to each other when they are opposed to each other in a normal positional relationship. Yes.

  An elastic locking claw 18 having an outward claw 18a extending in the front-rear direction at the lower end is provided at the lower end front and rear portions of the opposed portions of the half halves 12A and 12B. When facing and joining, the elastic locking claws 18, 18 facing left and right are joined together, and the joined two elastic locking claws 18, 18 close the bottom wall of the armrest support cylinder 11. By engaging and locking in an engagement hole 19 (see FIGS. 7 and 8) provided in 11a, the intermediate cylinder 12 can be removed from the armrest support cylinder 11 without the position of the halves 12A and 12B being displaced. It has been stopped.

  The height adjusting device 15 has an operation portion 21a that projects forward and downward through a notch 20 provided on the upper front surface of the armrest support rod 14, and a downward U-shaped engagement recess 21b at the rear end portion. And an operating lever 21 pivotally attached to the upper part of the armrest support rod 14 with a projecting shaft 21c whose middle part faces in the left-right direction, and a side face that is substantially rhombus long in the vertical direction, with the middle part as the center A shaft portion 22a that is fitted in the armrest support rod 14 so as to be rotatable, is received in the engagement recess 21b of the operation lever 21 and engages with the upper end portion, and is provided on the lower end portion. Through the long holes 23 provided in the side walls slightly below the armrest support rod 14 facing in the front-rear direction, the intermediate portion of the engagement pin 24 penetrating the armrest support rod 14 in the left-right direction is directed in the left-right direction. Rotating lever provided with pin insertion hole 22b 2 and an engagement hole 25 provided in each of the half pieces 12A and 12B of the intermediate cylinder 12 and fitted to each end of an engagement pin 24 protruding to both sides of the armrest support rod 14. It has.

  The operating lever 21 is fitted with the protruding shafts 21c provided on both side surfaces of the intermediate portion thereof into a pair of left and right recessed portions 26 provided on the opening edge of the upper end of the armrest support rod 14 from above and the operating lever. 21 is brought into contact with the lower surface of the closing member 27 that closes the upper end opening of the armrest support rod 14, thereby preventing the protruding shaft 21 c from coming out of the recess 26, and the upper portion of the armrest support rod 14. It is designed to be easily installed.

  The closing member 27 has a disk shape and is fixed to the upper end of the armrest support rod 14 with a plurality of set screws 28, thereby forming a part of the armrest support rod 14. At the center of the upper surface of the closing member 27, an upward shaft 29 is provided in which an upper end of the circular shaft portion 29a is connected to a non-circular shaft portion 29b that is an angular axis.

  In the middle of the pivot lever 22 in the vertical direction, it is inscribed in the front and rear inner surfaces of the armrest support rod 14 and protrudes forward and backward in the portion corresponding to the top of the rhombus in the same arc shape. The bulging portion 22c is provided, and the turning lever 22 can be turned in the armrest support rod 14 around the center of curvature of the bulging portion 22c without any special pivot. .

  The engagement holes 25 provided in each of the half pieces 12A and 12B have a long hole-like connecting hole 25a facing the axial direction of the intermediate cylinder 12, and a forward groove on the front edge thereof. A plurality of recessed engagement portions 25b provided in a shape, and each end portion of the engagement pin 24 protruding to both sides from the armrest support rod 14 is fitted in the communication hole 25a. The engagement pin 24 and the armrest support rod 14 can freely move in the vertical direction with respect to the intermediate cylinder 12 and the armrest support cylinder 11, and the engagement pin 24 is provided with any of the recessed engagement portions 25b. When engaged, the vertical movement of the engagement pin 24 and the armrest support rod 14 is prevented.

An elastic tongue piece 30 that faces rearward and upward is integrally formed at the lower end portion of the rotating lever 22, and the distal end portion of the elastic tongue piece 30 is in pressure contact with the rear inner surface of the armrest support rod 14. As shown by a solid line in FIG. 8, the rotation lever 22 is always urged toward the locking position where the engagement pin 24 engages with any of the recessed engagement portions 25 b in the engagement hole 25. .
In other words, the elastic tongue piece 30 constitutes a biasing means that biases the rotation lever 22 toward the direction in which the engagement pin 24 engages with any of the recessed engagement portions 25b.

  Therefore, as indicated by a solid line in FIG. 8, the engaging pin 24 is normally engaged with any of the recessed engaging portions 25b by the action of the urging means, and the armrest 13 is engaged with the recessed engaging portion. The operation lever 21 is held at a height corresponding to the joint portion 25 b, and the operation lever 21 is located at a non-operation position where the operation portion 21 a protrudes forward and downward from the notch 20.

When it is desired to change the height of the armrest 13 from this state, first, the operating portion 21a of the operating lever 21 is moved from the non-operating position against the urging force of the elastic tongue 30 from the imaginary line in FIG. As shown by, it is turned upward toward the upper operation position.
Then, the engaging recess 21b at the rear portion of the operation lever 21 rotates forward, and accordingly, the rotating lever 22 in which the engaging recess 21b and the shaft portion 22a at the upper end are engaged is imagined in FIG. As shown by the line, the engagement pin 24 is rotated counterclockwise, and the engagement pin 24 is disengaged from the recessed engagement portion 25b of the engagement hole 25 and is moved to the unlocking position where the engagement pin 25 is fitted in the communication hole 25a. Moved.

Next, the armrest 13 and the armrest support rod 14 are raised or lowered to a desired height while the operation portion 21a of the operation lever 21 is held at the operation position.
At this time, since the engagement pin 24 is located in the communication hole 25a, the engagement pin 24 can freely move up and down in the communication hole 25a.

  After the armrest 13 is set to a desired height, when the hand is released from the operating portion 21a of the operating lever 21 or the operating force is loosened, the rotating lever 22 is moved to the original locking position by the biasing force of the elastic tongue 30. The engagement pin 24 is engaged with the nearest recessed engagement portion 25b at that time. When the engagement pin 24 does not properly engage with any of the recessed engagement portions 25b, the armrest 13 may be moved slightly up or down.

  When the engagement pin 24 is properly engaged with one of the recessed engagement portions 25b and the rotation lever 22 is returned to the locking position, the operation lever 21 is also returned to the non-operation position. .

  Further, when assembling the armrest device 9, the operation lever 21 is mounted on the armrest support rod 14, the operation lever 21 is positioned, and the rotation lever 22 is directed upward from the lower end of the armrest support rod 14. The rear end portion of the operation lever 21 and the upper end portion of the rotation lever 22 are engaged with each other via the engagement recess 21b, and the elongated hole 23 of the armrest support rod 14 and the rotation lever 22 are It can be easily assembled with the pin insertion hole 22b aligned. At this time, the operating lever 21 is positioned in the non-operating position by its own weight by forming the operating portion 21a to be heavy so that the center of gravity is located closer to the operating portion 21a than the protruding shaft 21c. 22 is positioned at the locking position by pressing the elastic tongue piece 30 against the inner surface of the rear part of the armrest support rod 14, so it is necessary to provide special positioning means for the operation lever 21 and the rotation lever 22. Absent.

  In this state, after the engaging pin 24 is passed through the elongated hole 23 of the armrest support rod 14 and the pin insertion hole 22b of the rotating lever 22 that are aligned with each other, both the half pieces 12A, 12B are faced to each other and both ends of the engagement pin 24 are engaged with a predetermined recessed engagement portion 25b so that the armrest support rod 14 is sandwiched between them, and these are joined together as an armrest support. By inserting the elastic locking claws 18 and 18 corresponding to the left and right jointed into the cylinder 11 from above into the engagement hole 19 in the bottom wall 11a of the armrest support cylinder 11, a screw or the like is obtained. The armrest support cylinder 11, the intermediate cylinder 12, the armrest support rod 14, the operation lever 21, the rotation lever 22 and the like can be easily and reliably assembled without using any of them.

Next, the structure of the armrest 13 will be described with reference to FIGS. 3 and 8 to 14.
The armrest 13 is composed of a horizontal plate-like armrest substrate 31 made of a hard synthetic resin material and extending in the front-rear direction, a core material 32 made of a soft synthetic resin material covering the upper surface, a cushion material 33 made of foamed polyurethane, and an elastomer. An armrest pad 34.

A long hole 35 that is long in the front-rear direction is provided at the center near the rear portion of the armrest substrate 31, and an upright piece 36 that sandwiches the peripheral edge between the core member 32 and the armrest pad 34 from the inside and outside is formed obliquely upward on the peripheral edge of the upper surface. A projecting edge 37 is provided.
Engagement holes 39 are provided at a plurality of locations on the outer peripheral surface of the standing piece 36 to engage with inward claws 38 provided at appropriate positions on the periphery of the core member 32.

On both sides of the long hole 35 on the upper surface of the armrest substrate 31, a pair of left and right projecting pieces 40, 40 that are parallel to the side edges of the long hole 35 are projected upward. Both projecting pieces 40, 40 have a waveform in a plan view so that a plurality of concave portions 41 are formed in the front-rear direction on the outer surface.
A large number of ribs 42 are provided on the upper surface of the armrest substrate 31 in the front-rear direction and the left-right direction.

The lower surface of the armrest substrate 31 is provided with a rectangular concave portion 43 that is long in the front-rear direction so as to surround the elongated hole 35. When the armrest substrate 31 is moved forward, the elongated hole 35 is exposed downward. A shielding plate 44 that prevents this is slidably fitted in the front-rear direction.
The shielding plate 44 is provided with a long hole 45 that is long in the front-rear direction and into which a fitting portion of a support block described later is fitted.

The armrest 13 includes a support block 46 and a fixed disk (fixed plate) 47 so that the armrest 13 can rotate about a vertical axis and can move in the front-rear direction.
The support block 46 includes a fitting portion 48 having the same width as the left and right width of the elongated hole 35 of the armrest substrate 31, and a widening portion 49 that is connected to the upper end of the fitting portion 48 and widens in the front-rear and left-right directions. A shaft hole 50 provided substantially at the center is externally fitted to a circular shaft portion 29 a of a shaft 29 protruding from the closing member 27, and is pivotally mounted on the armrest support rod 14.

  A non-circular shaft portion of the shaft 29 is formed by fitting a fixed disc 47 into a circular recess 51 provided on the upper surface of the widened portion 49 in the support block 46 and providing a square hole 52 provided in the center of the lower surface of the fixed disc 47. The support block 46 is prevented from being detached from the shaft 29 by being fitted to 29 b and fixing the fixed disk 47 to the upper end of the shaft 29 with a fixing screw 53 from above.

  Then, the armrest substrate 31 is placed on the upper end of the armrest support rod 14, and the fitting in the support block 46 is inserted into the elongated hole 35 in the armrest substrate 31 and the elongated hole 45 in the shielding plate 44 mounted below the armrest substrate 31. The armrest substrate 31 is slidable in the front-rear direction by supporting the joint portion 48 and sandwiching the armrest substrate from above and below by the widened portion 49 of the support block 46 and the upper surface of the armrest support rod 14. Together with the block 46, the armrest support rod 14 is mounted so as to be rotatable about the shaft 29.

  In front of the recess 51 on the upper surface of the support block 46, a square hole 54 and a narrow communication hole 55 that connects the rear center of the square hole 54 and the recess 51 are provided, and are fitted into the square hole 54. Due to the urging force of the elastic body 56 made of rubber or the like, the engaging pin 57 provided in the communication hole 55 facing the vertical direction is pressed toward the outer peripheral surface of the fixed disk 47, and the engaging pin 57 is fixed to the fixed disk. By elastically engaging a plurality of recesses 58 arranged in the circumferential direction on the outer peripheral surface of 47, an appropriate moderation feeling is imparted to the rotation of the support block 46.

  A fan-shaped concave portion 59 concentric with the shaft hole 50 is provided behind the concave portion 51 on the upper surface of the support block 46, and a convex portion 60 provided on the outer peripheral surface of the fixed disk 47 is fitted therein. Thus, the rotation range of the support block is restricted.

  The upper ends of both sides of the widened portion 49 of the support block 46 are connected to the base end portions of the elastic tongue pieces 61, 61 facing downward, and the chevron protrusions 61 a provided on the inner surface of the distal end portion of each elastic tongue piece 61. Are pressed against the outer surface of the protrusions 40 of the armrest substrate 31 where the recesses 41 are present, so that when the protrusions 61a are elastically engaged with the recesses 41, a sense of moderation is imparted so that the resistance is increased. It is.

  In this embodiment, the longitudinal movement guide means of the armrest substrate 31 comprising the long hole 35 provided in the armrest substrate 31 and the fitting portion 48 in the support block 46, and a plurality of concave portions 41 are provided side by side in the front-rear direction. The moderation feeling imparting means comprising the protruding piece 40 and the elastic tongue piece 61 provided on the side surface of the widened portion 49 in the support block 46 is provided separately from each other, so that the armrest substrate 31 can be moved back and forth stably and smoothly. Further, the projecting piece 40 can be integrally formed with the armrest base plate 31 and the elastic tongue piece 61 can be integrally formed with the support block 46, so that the number of parts can be reduced and assembled easily. Can do.

  In addition, since the protruding piece 40 and the elastic tongue piece 61 are provided in a pair so as to be symmetric with respect to the elongated hole 35 in the armrest substrate 31, the armrest substrate 31 is stabilized in a balanced manner on the left and right sides. And can be moved back and forth smoothly.

  Furthermore, by making the support block 46 pivotable about an axis orthogonal to the upper surface of the armrest support rod 14, the armrest substrate 31 can be slid in the front-rear direction with respect to the armrest support rod 14, and the left-right direction Therefore, the armrest substrate 31 can be smoothly moved back and forth, and can also be rotated stably and smoothly in the left-right direction.

  Moreover, a shielding plate 44 is provided between the upper surface of the armrest support rod 14 and the lower surface of the armrest substrate 31 to prevent the elongated hole 35 of the armrest substrate 31 from being exposed downward when the armrest substrate 31 is moved forward. Therefore, fingers and the like are not sandwiched between the long holes 35, and the long holes 35 are not exposed to the outside, so that the appearance is good.

The present invention is not limited to the above-described embodiments, and can be implemented in various modified forms without departing from the scope of the claims.
For example, a plurality of concave portions 41 may be provided on the inner side surface of the projecting piece 40 in the front-rear direction, and the tip portion of the elastic tongue piece 61 may be in pressure contact with the inner side surface from the inside.

It is a perspective view of a chair provided with one embodiment of the armrest device of the present invention. Similarly, it is a side view. It is a disassembled perspective view of an armrest apparatus. It is an expansion disassembled perspective view of the part of the height adjustment apparatus in an armrest apparatus. It is a disassembled perspective view which shows the state which attached some members from the state of FIG. 4 illustration. Similarly, it is a perspective view which shows an assembly completion state. It is the perspective view which looked at the completed armrest apparatus from diagonally downward. Similarly, it is a vertical side view. It is the disassembled perspective view which looked at the upper part of the armrest from diagonally upward. It is the disassembled perspective view which looked at the upper part of the armrest from diagonally downward. It is an expansion vertical side view of the upper part of an armrest. It is a cross-sectional plan view which follows the XII-XII line | wire of FIG. It is a cross-sectional plan view which follows the XIII-XIII line | wire of FIG. It is a top view of an armrest which removes and shows a core material, a cushion material, and an armrest pad.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Caster 2 Leg rod 3 Leg column 4 Support base 5 Support link 6 Seat 7 Axis 8 Backrest 9 Armrest device 10 Bracket 11 Armrest support cylinder 11a Bottom wall 12 Intermediate cylinder 12A, 12B Half piece 13 Armrest 14 Armrest support collar 15 Height Adjusting device 16 Concave part 17 Convex part 18 Elastic locking claw 18a Claw 19 Engagement hole 20 Notch 21 Operation lever 21a Operation part 21b Engagement concave part 21c Projection shaft 22 Rotating lever 22a Shaft part 22b Pin insertion hole 22c Part 23 long hole 24 engaging pin 25 engaging hole 25a connecting hole 25b recessed engaging part 26 recessed part 27 closing member 28 set screw 29 shaft 29a circular shaft part 29b non-circular shaft part 30 elastic tongue piece (biasing means)
31 Armrest substrate 32 Core material 33 Cushion material 34 Armrest pad 35 Long hole 36 Standing piece 37 Projection edge 38 Claw 39 Engagement hole 40 Projection piece 41 Recess 42 Rib 43 Concave 44 Shield plate 45 Long hole 46 Support block 47 Fixing disk ( (Fixing plate)
48 fitting part 49 widening part 50 shaft hole 51 concave part 52 square hole 53 fixing screw 54 square hole 55 communicating hole 56 elastic body 57 engaging pin 58, 59 concave part 60 convex part 61 elastic tongue piece 61a protrusion

Claims (4)

  An armrest substrate whose upper surface is covered by an armrest pad is placed on the upper end of an armrest support rod that is supported so as to stand upright from the side of the seat, and the armrest support is mounted in a long hole facing the front and rear direction provided on the armrest substrate. A fitting portion having the same width as the left and right width of the long hole in the support block provided at the upper end of the heel is fitted, and the widened portion provided at the upper end of the fitting portion in the support block and the upper surface of the armrest support ridge The armrest substrate is mounted on the armrest support rod so that the armrest substrate can be slid in the front-rear direction by sandwiching the armrest substrate from above and below, and is provided on the armrest substrate so as to be parallel to the side edge of the elongated hole. A plurality of recesses are provided side by side in the front-rear direction, and the tip of the elastic tongue provided on the side of the widened portion of the support block is brought into pressure contact with the side of the protrusion having the recess, whereby the armrest substrate A sense of moderation is added to the back and forth movement of It was adapted to the armrest apparatus chair according to claim.   A pair of projecting pieces are provided symmetrically on both sides of the long hole in the armrest substrate, and a pair of elastic tongue pieces that are in pressure contact with the side surfaces of the projecting pieces are provided on both sides of the widened portion of the support block. The armrest device for a chair according to claim 1 provided symmetrically.   By making the support block pivotable about an axis perpendicular to the upper surface of the armrest support rod, the armrest substrate can be slidable in the front-rear direction and pivotable in the left-right direction with respect to the armrest support rod. The armrest device of the chair according to claim 1 or 2.   4. A shielding plate is provided between the upper surface of the armrest support rod and the lower surface of the armrest substrate, and when the armrest substrate is moved forward, a shield plate that prevents the elongated hole of the armrest substrate from being exposed downward is provided. The armrest apparatus of the chair in any one.

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