JP4888954B2 - Chair headrest device - Google Patents

Description

  The present invention relates to a headrest device for a chair, in which a headrest is supported on a guide rail provided on a headrest frame extending upward from a backrest so that the vertical position can be adjusted.

An example of this type of headrest device is disclosed in Patent Document 1.
JP 2004-202062 A

  In the headrest device described in Patent Document 1, a headrest frame (headrest column) having a plurality of upper and lower engagement grooves (ratchet teeth) is attached to a backrest support frame (back column) so as to be movable up and down. A headrest provided on the headrest frame by selectively elastically engaging an engagement member (locking piece) formed on a seat plate fixed to the backrest support frame with a fixing tool and a screw in the engagement groove. The vertical position of can be adjusted.

For this reason, when the engaging member is worn or damaged, it is necessary to replace the entire seat plate in which the engaging member is integrally formed, which increases the cost.
Further, in order to replace the seat plate, it is necessary to loosen the screw and remove the fixture, and the replacement work is troublesome.

  Furthermore, since the engaging groove is provided directly in the headrest frame, when it wears out, it is necessary to replace the entire headrest frame, which also increases the cost.

  The present invention has been made in view of the above-described problems. Only the engagement member that selectively engages with the engagement groove can be replaced, so that the cost can be reduced and the replacement operation can be easily performed. It is an object of the present invention to provide a headrest device for a chair that can be made of.

According to the present invention, the above problem is solved as follows.
(1) An elevating bracket provided on the headrest is slidably attached to a guide rail facing the vertical direction provided on the headrest frame extending upward from the backrest, and the elevating bracket and the guide rail are A plurality of upper and lower engaging grooves are provided on one of the opposing surfaces, and a non-circular concave holding portion that opens to the engaging groove side is provided on the other side, and the engaging groove is selected as the engaging groove. An engaging member having an elastic piece provided with an engaging protrusion that is elastically engaged is detachably fitted.

(2) In the above item (1), the engaging groove is provided on the front surface of the guide rail, and the lifting bracket is substantially rearwardly viewed in plan view so that the guide rail can be slidably moved upward and downward from the front. A square hole as a concave holding portion is provided in the front piece facing the vertical direction, and the engagement member is fitted into the square hole from the rear side while preventing the engagement member from coming off forward.

(3) In the above item (2), the engaging member includes a base piece having a square shape that can be fitted into the square hole, and a pair of retaining pieces projecting from at least the upper and lower edges of the base piece. The engagement member is prevented from coming off forward from the square hole by abutting against the rear surfaces of the upper and lower opening edges of the square hole.

(4) In the above item (3), a base end of an elastic piece that is elastically deformable in the front-rear direction is connected to the rear surface of the base piece, and a guide rail is provided on the rear surface of the free end portion of the elastic piece. An engaging protrusion that elastically engages with an engaging groove provided on the front surface is provided.

(5) In any one of the above items (2) to (4), a guide rail made of a synthetic resin having a separate member on the front surface of the headrest frame and having an engagement groove on the front surface is detachably fixed. To do.

According to the first aspect of the present invention, when the engaging member is worn, etc., it is possible to remove and replace it, and it is not necessary to replace the lifting bracket or the guide rail itself, so that the cost can be reduced. .
Further, since the engaging member is only fitted into the concave holding portion and no fixing means such as a screw is used, the replacement work can be performed very easily.

  According to the second aspect of the present invention, the lifting bracket has a backward U-shape, sandwiches the guide rail from the front, and the engaging member also fits into the square hole of the front piece of the lifting bracket. The lifting bracket and the engaging member are substantially integrated with each other, and can slide up and down stably along the guide rail without wobbling in the vertical and horizontal directions, and the engaging protrusion. Is reliably engaged with the engaging groove.

Further, since the engaging member is fitted to the front piece of the lifting bracket having a backward U-shape, there is no fear that it is exposed from the side, and the appearance is improved.
Furthermore, the engaging member can be easily removed from the square hole by pushing it backward from the front of the square hole.
By providing the engagement groove on the guide rail side, the vertical dimension of the lifting bracket can be minimized, and the appearance thereof is improved.

  According to the third aspect of the present invention, the base piece of the engaging member is simply fitted into the square hole from the rear, and the upper and lower retaining pieces can be easily prevented from coming forward from the square hole. Done.

  According to the invention described in claim 4, since the elastic piece is easily bent in the front-rear direction, the engaging protrusion provided at the free end thereof is easily elastically engaged with the engaging groove of the guide rail. .

  In addition, the engaging protrusion of the free end portion of the elastic piece is always in pressure contact with the front surface of the guide rail, and by the reaction force, the engaging member is urged forward, so that the base piece is detached rearward from the square hole. No fear of doing.

  According to the fifth aspect of the present invention, the guide rail is separate from the headrest frame and is made of synthetic resin. For example, the headrest frame is made of metal and part of the guide rail has an engagement groove. As a result, the guide rail can be formed at a low cost, and only the guide rail can be easily replaced when the engaging groove or the like is worn.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a chair to which the present invention is applied, FIG. 2 is a rear view of the chair, and the chair includes a leg (2) with casters (1) and a pedestal (3) standing up from the center. The support base (5), which is attached to the upper end of the support base (5), and the lower end of the support base (5) is pivotally attached to both sides of the support base (5). Is a back support frame (6) that is standing in the rear of the seat body (4) and has a substantially vertically downward U shape, and left and right 1 attached to the lower ends of both sides of the back support frame (6). It has a pair of armrests (7) and (7).

  A mesh-like backrest plate (9) on the rear surface of the backrest (8) is attached to the front surface of the backrest support frame (6).

  As shown in FIG. 3, the back support frame (6) is formed in a rearward convex arc shape by a pair of left and right side frames (10), (10) formed of aluminum alloy or the like, and also of aluminum alloy or the like. The upper frame (11) is made of.

  On the opposing surface at the upper end of both side frames (10), there are connecting pieces (10a) (10a) whose upper and lower dimensions are equal to those of the upper frame (11). It protrudes diagonally rearward and inward with a curvature almost equal to that of the two side ends.

  Bolt insertion grooves (12) that open to the front are formed on the front surfaces of both end portions of the upper frame (11), and the bolts (13) inserted into the bolt insertion grooves (12) are connected to the upper frame (11). The upper frame (11) is inserted into the upper ends of the left and right side frames (10) by inserting the side ends and screwing into the screw holes (not shown) to be provided on the inner surface of the coupling piece (10a). It looks nicely combined to give a sense of unity.

  (14) and (14) are a pair of left and right projections for attaching the upper end of the backrest plate (9) to the front of the backrest support frame (6), and the front of the upper end of both side frames (10). The upper and lower female screw holes (15) are formed in both protrusions (14) (see FIG. 4).

The headrest device (16) of the present invention is provided at the upper end of the back support frame (6).
The headrest device (16) includes a headrest frame (17) made of aluminum alloy or the like having a U-shape when viewed from the front, and a headrest (18) attached to the front surface thereof.

  As shown in FIG. 3, the headrest frame (17) has a pair of left and right downside ridges (17a) and (17a) whose left and right spacing dimensions are substantially equal to the spacing dimensions between the side frames (10) and (10). A horizontal bar (17b) that curves backward in a convex arc shape is integrally formed on the upper end of the upper and lower ends.

The front and rear and left and right dimensions of the lower end portion of the downward side flange (17a) are substantially equal to the front and rear and left and right dimensions of the upper end portion of the side frame (10) so that they have a sense of unity after mounting.
The headrest frame (17) is connected to the upper end of the backrest support frame (6) as follows.

  As shown in FIG. 4, at the upper ends of the left and right side frames (10) in the back support frame (6), there are bottomed recesses (19) that open upward in a short vertical dimension. Also, a female screw hole (20) having a small diameter and a long vertical dimension is formed so as to communicate with each other.

  At the lower end of the left and right downward flanges (17a) of the headrest frame (17), a stepped hole that opens downward, i.e., an upward concave hole (21) with a short vertical dimension, and a smaller diameter than that A connecting hole (22) having a long vertical dimension is formed in communication with each other.

(23) is a connecting member made of hard metal facing in the vertical direction, the screw shaft (24) at the lower end, the intermediate connecting shaft (25) having a diameter larger than that, and the intermediate connecting shaft (25). It has a small-diameter upper connecting shaft (26) and a short hexagonal shaft (27) connected to the upper end thereof.
The vertical dimension of the upper connecting shaft (26) and the hexagonal shaft (27) is slightly shorter than the connecting hole (22).

The screw shaft (24) is screwed into the female screw hole (20) of the side frame (10), and the lower half and the upper half of the intermediate connecting shaft (25) are recessed portions of the side frame (10), respectively. (19) is fitted into the recessed hole (21) of the downward side flange (17a), and the upper connection shaft (26) and the hexagonal shaft (27) are connected to the connection hole (22) of the downward side flange (17a). To be fitted.
An annular groove (28) is formed on the outer peripheral surface of the intermediate portion of the upper connecting shaft (26).

  In order to attach the headrest frame (17) to the backrest support frame (6), the screw shaft (24) at the lower end of the connecting member (23) is first inserted into the female screw holes (20) of the left and right side frames (10). Is screwed until the lower end of the intermediate connecting shaft (25) contacts the bottom surface of the recess (19), so that the connecting member (23) is connected to the upper half of the intermediate connecting shaft (25) at the side portion. Install so that it protrudes above the upper end of the frame (10).

  At this time, by rotating the hexagonal shaft (27) at the upper end of the connecting member (23) with a tool such as a spanner, the screw shaft (24) can be easily screwed into the female screw hole (20). Further, since the lower end of the intermediate connecting shaft (25) can be brought into strong contact with the bottom surface of the recess (19) by tightening firmly, the connecting member (23) can be firmly attached to the side frame (10).

  Next, the lower end of both the downward side ridges (17a) of the headrest frame (17) is opposed to the upper ends of the left and right side frames (10), and a concave hole provided at the lower end of the downward side ridge (17a) ( 21) and the connecting hole (22) are fitted into the protruding portion of the connecting member (23), that is, the upper half of the intermediate connecting shaft (25) and the upper connecting shaft (26), respectively.

  Next, it faces the front-rear direction communicating with the connection hole (22), which is formed in advance on the front surface of the lower end portion of the downward side flange (17a) so as to correspond to the annular groove (28) of the connection member (23). A slotted set screw (30) is inserted into the female screw hole (29) through a through hole (33) drilled in a guide rail (31) described later and screwed into the annular groove (28). Press.

  Thereby, the downward side ridge (17a) is secured to the connecting member (23), and the lower end of the headrest frame (17) is attached to the upper end of the backrest support frame (6).

  As shown in FIG. 3 and FIG. 4, the front surface of the left and right downward side ridges (17 a) in the headrest frame (17) is slightly shorter than the vertical dimension, and the left and right dimensions are substantially equal. A pair of synthetic resin guide rails (31) and (31) that support the headrest (18) and guide it up and down are attached by fixing the upper and lower ends with bolts (32).

A through hole (33) for inserting the set screw (30) is formed at the lower end of both guide rails (31).
On both side surfaces of both guide rails (31), a pair of left and right first guide grooves (34) and (34) having an inward concave shape whose lower end opens downward are formed to the vicinity of the upper end (see FIG. 5).

  Also, in the center of the front of both guide rails (31), there is a second concave guide groove (35) that opens to the front and faces backwards and concaves, and the upper and lower sides that face slightly to the left and right. The plurality of engaging grooves (36) are formed orthogonal to each other such that the second guide groove (35) is located at the center.

  On the left and right guide rails (31), a pair of elevating brackets (37) and (37) for supporting the headrest (18) and elevating are attached as follows.

  As shown in FIGS. 3 to 5, both the lifting brackets (37) are composed of, for example, a hard bracket body (38) formed of a fiber reinforced synthetic resin material and a softer synthetic resin material (for example, polyacetal resin). And an engaging member (39) formed by

  The bracket body (38) has a pair of left and right side pieces (38a) (38a) whose front-to-rear surface dimensions are approximately equal to the left-right dimensions of the guide rail (31), and a front piece having a square hole (40). 38b), a support cylinder (41) is formed integrally with the front upper end of both side pieces (38a) so as to face in the left-right direction.

  The center part of the opposing surface of both side pieces (38a) is a pair of first guide projecting pieces facing in the vertical direction that can be slidably fitted into the left and right first guide grooves (34) of the guide rail (31). (42) and (42) are integrally projected.

  As shown in an enlarged view in FIG. 6, the engaging member (39) can be fitted into the square hole (40) of the front piece (38b), and has a horizontal portion at the upper end and a base piece (39a facing upward). ) And an elastic piece (39b) standing up from the rear surface of the lower end portion thereof, and a second guide provided on the front surface of the guide rail (31) is provided at the upper end (free end portion) of the elastic piece (39b). A second guide protrusion (43) facing vertically, which can be slidably fitted in the groove (35) up and down, and a plurality of upper and lower engagements on the front side of the guide rail (31) provided on both sides of the second guide protrusion (43) Engaging protrusions (44) (44) that can be selectively engaged with the groove (36) and are horizontal in the left-right direction with a projecting dimension smaller than that of the second guide protrusion (43). , Projecting integrally in the rearward direction.

  At the upper and lower edges of the base piece (39a), it is rearward in the locking step (45) (45) formed at the upper and lower opening edges of the square hole (40) on the rear surface side of the front piece (38b). By fitting more tightly, the retaining pieces (46) (46) for preventing the square hole (40) from slipping forward and preventing the movement in the vertical direction are provided so as to protrude in the opposite directions. Yes.

  To attach the lifting bracket (37) to the guide rail (31), after fitting the engagement member (39) into the square hole (40) of the front piece (38b) in the bracket body (38), The first guide protrusions (42) and (42) on the inner surface of both side pieces (38a) are fitted into the first guide grooves (34) and (34) on both side surfaces of the guide rail (31) from the opening end at the lower end. Let At the same time, the upper end of the elastic piece (39b) of the engaging member (39) is pressed against the lower front surface of the guide rail (31) and bent forward, and the entire lifting bracket (37) is moved upward. The second guide protrusion (43) of the elastic piece (39b) is fitted into the second guide groove (35) on the front surface of the guide rail (31).

  Thus, the lifting bracket (37) is attached so as to be movable up and down so as to sandwich the guide rail (31) from the front, and the second guide protrusion (43) is the lower end of the second guide groove (35). Is prevented from falling off and the maximum downward movement amount is restricted. The maximum amount of upward movement of the lifting bracket (37) is regulated by the first guide protrusion (42) coming into contact with the upper end of the first guide groove (34).

  When the elevating bracket (37) is moved in the vertical direction, the elastic piece (39b) is elastically deformed in the front-rear direction, so that the engaging protrusions (44) provided on the elastic piece (39b) have a plurality of front surfaces of the guide rail (31). The vertical position (height) of the headrest (18) that is selectively engaged with any one of the engagement grooves (36) and attached to the lifting bracket (37) can be adjusted.

  As shown in FIGS. 3 and 4, a pair of mounting pieces (48) and (48) having mounting holes (47) facing in the left-right direction are provided at the lower ends of the left and right sides of the rear surface of the headrest (18). The cover (49) is inserted and protrudes backward.

  As shown in FIG. 8, the rear end of the mounting piece (48) is rotatably fitted on the front surface of the center portion of the support cylinder (41) in the left and right lifting brackets (37). A rearward concave mounting groove (50) is formed.

  As shown in FIG. 3 and FIG. 8, the mounting hole (47) of the mounting piece (48) loosely fitted in the mounting groove (50) has one side portion (right side in FIG. 8) communicating with the mounting groove (50). The cylindrical portion (52a) of the frictional force applying member (52) inserted from the stepped hole (51) in the half portion is fitted. At the right end of the cylindrical portion (52a) of the frictional force imparting member (52), the outer diameter of the inner end is larger than the outer diameter of the cylindrical portion (52a), and the outer diameter gradually decreases toward the outer end. Thus, the conical portion (52b) whose outer peripheral surface is tapered is integrally connected, and the whole is integrally formed of a hard synthetic resin (for example, polyacetal resin).

  As shown in FIG. 7, a protrusion (53) is connected to a part of the outer peripheral surface of the cylindrical portion (52a), and this protrusion (53) is attached to the mounting piece (48) as shown in FIG. ), The frictional force applying member (52) is fitted in such a manner that it cannot rotate relative to the mounting piece (48). Are combined.

  (55) is a substantially cylindrical frictional force imparting member, which is fitted into the inner small diameter part (51a) of the stepped hole (51) in the support cylinder (41) as shown in FIGS. A small-diameter cylindrical portion (55a), a short large-diameter flange portion (55b) that is fitted to the outer large-diameter portion (51b) of the stepped hole (51), and the large-diameter flange portion ( 55b) is provided with three projecting strips (55c) continuously provided at intervals of 120 ° in the circumferential direction on the outer peripheral surface of the intermediate portion of the small diameter cylindrical portion (55a).

  In addition, a tapered hole that complements the tapered outer peripheral surface of the small-diameter cylindrical portion (55a) is fitted with the conical portion (52b) of the frictional force applying member (52). (56) is formed.

  The three protruding strips (55c) are formed in three concave grooves (57) that are formed on the inner peripheral surface of the small-diameter portion (51a) of the stepped hole (51) and open outward and inward. It is fitted and cannot rotate relative to the support tube (41).

  The frictional force applying member (55) is integrally formed of a synthetic resin material that is softer and slightly elastic than the frictional force applying member (52), for example, a polyurethane-based elastomer.

  The mounting piece (48), the frictional force imparting member (52), and the frictional force imparting member (55) are stepped holes formed at the side end of the support tube (41) opposite to the stepped hole (51). The shaft hole (59a) of the stepped bolt (59) inserted from (58) is connected to the shaft hole (60) (60) having the same diameter as the frictional force applying member (52) and the frictional force applying member (55). ), And by screwing the barbed nut (61) into the male thread portion (59b) protruding into the stepped hole (51), it is attached to the support cylinder (41), that is, the lifting bracket (37), In addition, after the mounting, the side end of the cylindrical portion (52a) of the frictional force applying member (52) contacts the inner surface of the mounting groove (50), and the outer peripheral surface of the conical portion (52b) and the frictional force applying member. The inner surface of the tapered hole (56) of (55) is in contact with each other so as to be relatively rotatable.

  At this time, the tightening allowance and the tightening force of the frictional force applying member (55) by the brazing nut (61) are set so that the inner surface of the tapered hole (56) is slightly elastically deformed in the diameter increasing direction. It is preferable that the inner surface of 56) be in strong pressure contact with the outer peripheral surface of the conical portion (52b). By doing so, the frictional resistance between the contact surfaces becomes large, and the frictional force applying member (52) is applied to the frictional force applying member (55) in a state where a relatively large frictional force is applied. It will turn.

  Therefore, the rotational resistance of the mounting piece (48) and the headrest (18) which are substantially integrated with the frictional force applying member (52) is also increased, and the position of the headrest (18) in the front-rear direction relative to the backrest (8) is increased. The tilt angle can be adjusted steplessly, and it is prevented that the tilt angle is rotated even after the adjustment.

  As described above, in the headrest device (16) of the above-described embodiment, the pair of right and left lifting brackets (37) that support the headrest (18) have a U-shape in a plan view, and the headrest frame ( 17) Hold both side surfaces of the guide rail (31) attached to the front of both downward facing rods (17a) from the front, and the inner side surface (opposite surface) of both side pieces (38a) of the left and right bracket bodies (38) The first guide protrusions (42) facing each other in the vertical direction are slidably fitted in the first guide grooves (34) on both sides of the left and right guide rails (31). Therefore, the headrest (18) can be moved up and down along the downwardly facing sides (17a) of the headrest frame (17) while stably supporting the headrest (18).

  In addition, a second guide groove (35) is provided in the center of the front surface of the left and right guide rails (31), and the second guide groove (35) is engaged between the both side pieces (38a) of the lifting bracket (37). The headrest (18) is more stable because the second guide projecting piece (43) facing the up and down direction protruding from the elastic piece (39b) of the joint member (39) is slidably fitted. Can move up and down.

  Furthermore, the headrest (18) is only supported via the lifting bracket (37) on the guide rail (31) provided on the front surface of the left and right side rods (17a) of the headrest frame (17), The degree of freedom in designing the entire headrest device (16) including the lifting bracket (37) and the headrest frame (17) is increased.

  Since the lower end of the first guide groove (34) opens downward, the first guide protrusion (42) can be easily fitted from the lower end, and the guide rail (37) of the lifting bracket (37) Installation to 31) becomes extremely easy.

  Further, since the second guide protrusion (43) protrudes from the rear surface of the upper end of the elastic piece (39b) which can be elastically deformed in the front-rear direction, it can be easily fitted into the second guide groove (35). After the fitting, the second guide protrusion (43) comes into contact with the lower end of the second guide groove (35), so that the lifting bracket (37) and the headrest supported by the lifting bracket (37) can be obtained by simple means. The dropout from the guide rail (31) of (18) is prevented.

  On the front surface of the guide rail (31), a second guide groove (35) and a plurality of upper and lower engaging grooves (36) facing in the left-right direction are perpendicular to each other with the second guide groove (35) positioned at the center. The second guide groove (35) is fitted with the second guide protrusion (43) at the center of the elastic piece (39b), and the engaging protrusions (44) on both sides sandwiching the second guide groove (35). Is engaged with the engagement groove (36), the engagement protrusion (44) is reliably and stably engaged with the engagement groove (36).

  Further, when the engagement protrusion (44) is detached from the engagement groove (36), the elastic piece (39b) bends forward, so that when the headrest (18) is raised and lowered, the headrest frame (17) No bending load or the like is applied to the left and right downward side rods (17a), and the vertical position of the headrest (18) can be easily adjusted with a light force.

  The elevating bracket (37) is a member that engages with the rear bracket-shaped rigid bracket body (38) that clamps the guide rail (31) from the front, and the engagement groove (36) of the guide rail (31). The engagement member (39) is composed of two members including an engagement member (39) having a mating protrusion (44), and the engagement member (39) is formed in a square hole (40) provided in the front piece (38b) of the bracket body (38). Since the engagement protrusion (44) is worn and held, it can be inserted and removed from the rear so that the lifting bracket (37) can be moved together with the headrest (18) from the lower end of the guide rail (31). It can be removed and only the engagement member (39) can be easily replaced.

  The engaging member (39) is held by the square hole (40) of the hard bracket body (38), and can be moved up and down stably integrally with the bracket body (38).

  In the above embodiment, the guide rail (31) is provided separately from the headrest frame (17) so that it can be replaced when it is worn, etc. And the front side thereof may be the same guide rail (31) as described above.

  Further, the position where the second guide groove (35) and the engagement groove (36) are provided may be, for example, one of the lateral side (17a) and the left and right side surfaces of the guide rail (31). At this time, the shape of the elevating bracket (37) may be a plane outward U-shape or inward U-shape.

  Further, the second guide groove (35) and the engagement groove (36) are provided on the rear surface side of the lifting bracket (37) having a large vertical dimension, contrary to the above embodiment, while the second guide protrusion ( 43) and an engaging member (39) including an elastic piece (39b) provided with an engaging protrusion (44) may be fitted into a concave holding portion provided on the front side of the guide rail (31).

  Instead of the square hole (40), the front piece (38b) of the lifting bracket (37) is provided with a square concave holding portion that opens to the rear, and the base piece (39a) of the engagement member (39) is provided on this. You may fit from back.

  In the above embodiment, the first guide grooves (34) are provided on both side surfaces of the left and right guide rails (31). However, the guide grooves (34) are provided only on the outer side surface or the inner side surface. Correspondingly, the first guide protrusion (42) of the lifting bracket (37) may be only one. Further, the backrest support frame (6) may be extended above the backrest (8) without using the headrest frame (17) as a separate body, and its upper end may be used as a headrest frame.

  In the above-described embodiment, the headrest (18) is attached to the pair of lifting brackets (37) by the guide rails (31) provided on the left and right side rods (17a) of the headrest frame (17) having a downward U shape when viewed from the front. For example, a slightly wider headrest frame is erected from the center upper end of the back support frame (6), and a guide rail having the same structure as the above is provided on the front surface. The headrest (18) may be supported by one lifting bracket similar to the above attached to the rail.

  In the above-described embodiment, the headrest (18) is attached to the pair of lifting brackets (37) by the guide rails (31) provided on the left and right side rods (17a) of the headrest frame (17) having a downward U shape when viewed from the front. For example, a slightly wider headrest frame is erected from the center upper end of the back support frame (6), and a guide rail having the same structure as the above is provided on the front surface. The headrest (18) may be supported by one lifting bracket similar to the above attached to the rail.

  In the above embodiment, the conical portion (52b) is provided on the frictional force applying member (52) side, and this conical portion (52b) is fitted into the tapered hole (56) of the frictional force applying member (55). The inner surface is pressed against the inner surface, but conversely, a conical portion may be provided on the frictional force applying member (55) side, and a tapered hole may be provided on the frictional force applying member (52) so as to face each other.

  Further, in order to increase the frictional resistance between the contact surfaces, the frictional force imparting member (55) is formed of a softer elastomer or the like than the frictional force imparting member (52), but the frictional force imparting member (55 ) Is made of the same material as the frictional force imparting member (52), and the required frictional resistance is obtained on the contact surfaces by adjusting the tightening force of the stepped bolt (59) and nut (61). Sometimes it can be done.

  The means for preventing the lifting bracket (37) from falling off from the guide rail (31) may be a pin or the like penetrating the lower end of the first guide groove (34) and facing in the left-right direction.

It is a side view of the chair to which this invention is applied. Similarly, it is a rear view. It is a disassembled perspective view of a headrest device. Similarly, it is a partially cutaway enlarged side view. FIG. 5 is an enlarged cross-sectional plan view taken along line VV in FIG. 4. It is an expansion perspective view of an engaging member. It is an expansion front perspective view of a frictional force provision member and a to-be-frictioned force provision member. It is the VIII-VIII line enlarged vertical end view of FIG. It is the IX-IX line vertical side view of FIG.

Explanation of symbols

(1) Casters
(2) Leg
(3) pedestal
(4) Seat
(5) Support base
(6) Back support frame
(7) Armrest
(8) Backrest
(9) Backrest board
(10) Side frame
(11) Upper frame
(12) Bolt insertion groove
(13) Bolt
(14) Mounting member
(15) Bolt
(16) Headrest device
(17) Headrest frame
(17a) Downward side fence
(17b) Yokohama
(18) Headrest
(19) Recess
(20) Female thread hole
(21) Recessed hole
(22) Connecting hole
(23) Connecting member
(24) Screw shaft
(25) Intermediate connecting shaft
(26) Upper connecting shaft
(27) Hexagon shaft
(28) Annular groove
(29) Female thread hole
(30) Set screw
(31) Guide rail
(32) Bolt
(33) Through hole
(34) 1st guide groove
(35) Second guide groove
(36) Engagement groove
(37) Lift bracket
(38) Bracket body
(38a) side piece
(38b) Front piece
(39) Engagement member
(39a) Base piece
(39b) Elastic piece
(40) Square hole (concave holding part)
(41) Support cylinder
(42) 1st guide protrusion
(43) Second guide protrusion
(44) Engagement protrusion
(45) Locking step
(46) retaining piece
(47) Mounting hole
(48) Mounting piece
(49) Back cover
(50) Mounting groove
(51) Stepped hole
(51a) Small diameter part
(51b) Large diameter part
(52) Friction force imparting member
(52a) Cylindrical part
(52b) Conical part
(53) Protrusion
(54) Groove
(55) Friction force imparting member
(55a) Small diameter cylinder
(55b) Large diameter collar
(55c) Projection strip
(56) Taper hole
(57) Groove
(58) Stepped hole
(59) Stepped bolt
(59a) Shaft
(59b) Male thread
(60) Shaft hole
(61) Bracket nut

Claims (5)

  A lifting bracket provided on the headrest is slidably attached to a guide rail facing the vertical direction provided on the headrest frame that extends upward from the backrest, and the opposite surface between the lifting bracket and the guide rail is mounted. Either one is provided with a plurality of upper and lower engaging grooves, and the other is provided with a non-circular concave holding portion that opens toward the engaging groove, and the concave holding portion is selectively elastic to the engaging groove. A headrest device for a chair, wherein an engaging member having an elastic piece provided with an engaging protrusion to be engaged is detachably fitted.   An engaging groove is provided on the front surface of the guide rail, and the lifting bracket has a substantially backward U-shape in plan view so that the guide rail can be slid upward and downward from the front. The headrest device for a chair according to claim 1, wherein a square hole as a concave holding portion is provided in the piece, and an engagement member is fitted into the square hole from the rear side while preventing the engagement member from coming off.   The engaging member includes a base piece having a square shape that can be fitted into the square hole, and a pair of retaining pieces projecting from at least the upper and lower end edges of the base piece are connected to the upper and lower opening edges of the square hole. 3. The headrest device for a chair according to claim 2, wherein the engagement member is prevented from coming out of the square hole by being brought into contact with the rear surface.   The base end of the elastic piece that can be elastically deformed in the front-rear direction is connected to the rear surface of the base piece, and the rear surface of the free end portion of the elastic piece is provided in pressure contact with the front surface of the guide rail. The headrest device for a chair according to claim 3, wherein an engagement protrusion that elastically engages with the engagement groove is provided.   The headrest of the chair according to any one of claims 2 to 4, wherein a guide rail made of a synthetic resin having a separate member on the front surface of the headrest frame and having an engaging groove on the front surface is detachably fixed. apparatus.

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