Abstract: In a configuration in which a holder holding a controller is mounted on a seat part with a plate-shaped member, the exposure of the mounting part of the plate-shaped member on which the holder is mounted is eliminated. A seat device includes a pressure sensor measuring a value relating to the seated person's state a vibration imparting device performing a vibration imparting operation, an ECU controlling the vibration imparting device corresponding to the measurement result of the pressure sensor, a holder holding the ECU, and a mounting bracket fixed to a lower frame such that the holder is mounted on the lower frame of a seat part. The mounting bracket includes a mounting projection on which a side wall of the holder is mounted in a predetermined mounting direction. When the side wall is mounted on the mounting projection, the mounting projection is covered with the side wall.

Abstract: An extreme ultraviolet (EUV) source includes a collector mirror, a drain, a droplet generator configured to eject a target material toward the drain, a pellicle disposed over the collector mirror. The pellicle is configured to catch debris formed of the target material.

Abstract: A reclining seat assembly includes a seat frame, and a backrest frame supported by the seat frame for pivoting movement about a backrest pivot axis. A seat pan has a forward portion supported by the seat frame for relative longitudinal movement, for example, using a slider. The seat pan has a rearward portion that is pivotally supported along a rear seat pan axis by a lower extension of the backrest frame, such that the backrest frame reclines relative to the seat frame upon forward longitudinal movement of the rear seat pan pivot axis relative to the seat frame. A backrest recline angle adjuster on the seat frame, such as a pair of linear actuators respectively coupling the seat frame to each side of the backrest frame along an actuator pivot axis that is itself offset from the backrest pivot axis, maintains a selected position of the rear seat pan support axis relative to the seat frame to thereby achieve a desired backrest inclination.

Abstract: In an aspect, the invention is directed to a chair that has a pedestal and an upper assembly including a body support assembly and a tilt control assembly. A biasing member is provided to bias the body support assembly towards an unreclined position. When the chair is empty the biasing member has a certain preload. When a person sits in the chair or when a downward force is applied to the upper assembly, there is relative movement between two chair components which causes an increase in the preload in the biasing member as compared to the preload when the chair is empty. As the downward force on the upper assembly increases, the preload in the biasing member increases.

Abstract: A chair and method of use is for a chair disposed upon a surface that is designed for a female anatomy; the chair includes a seat having proximate and distal end portions forming a first convex surface with a chord plane intersecting, the having a length shorter than its width. The chair includes a back having first and second end portions that form a second convex surface, wherein, a second lateral measure on the second end is less than a first lateral measure on the first end. The seat plane and an extension axis that is perpendicular to the surface are relatively positioned to one another to form an acute angle to one another, such that a user's femur bone lengthwise angles downward from hip to knee toward the surface while the user's shoulders arch rearward thus aligning the user's hip joint and shoulder joint vertically for better posture.

Abstract: An apparatus for sitting, including: a keystone assembly which connects various parts of the apparatus; a back that provides support for at least a person's back or shoulders; a floating lumbar support, which provides support for a person's lower back, attached to the keystone assembly; a seat that can adjust between a forward tilted and reclined position; a plurality of rollers, disposed on the keystone assembly, on which the seat rests; a central column, attached to the keystone assembly, on which the seat can spin; and a lower torsion spring connected to the seat and disposed on the keystone assembly allowing controlled movement of the seat.

Abstract: A seat assembly including a seat base, a back support, a support for the back support and/or for the seat base and at least one elastomer torsion-spring element. The back support and/or the seat base are/is pivotably hinged to the support in such a manner that a pivoting movement of the back support and/or of the seat base on a rotation axis can be carried out. During the respective pivoting movement of the back support and/or of the seat base with the elastomer torsion-spring element a restoring torque is generated that acts on the back support and/or on the seat base. The elastomer torsion-spring element includes an internal casing, an external casing encompassing the internal casing, and an elastomer body arranged in a space between the internal casing and the external casing. The elastomer body is rigidly connected to contact surfaces of the internal and external casings. The internal casing and/or the external casing are/is rotatably arranged on a rotation axis.

Abstract: A chair having a seat rotatably attached to a tilt spring portion of a tilt mechanism such that the tilt spring is activated by movement of the seat. A backrest and/or the seat can be rotatably connected to the tilt mechanism by parallel arm arrangements which permit the seat and backrest to tilt relative to each other. A tilt limiter can have a magnetic member which facilitates full movement of the tilt limiter between free and locked positions, and which creates an audible indication of full movement of the tilt limiter. The seat/backrest can be made from a flexible mesh material secured to a rigid overmolding which surrounds and is attached to an inner frame of the seat/backrest wherein an outer surface of the overmolding forms an outer surface of the seat/backrest frame and attachment of the overmolding causes the inner frame to stretch the mesh to a final condition.

Abstract: A chair assembly has a base frame, a pivot frame, a backrest frame, a seat frame and a backrest-adjusting device. The pivot frame is mounted pivotally on the base frame. The backrest frame is mounted securely on the pivot frame. The backrest-adjusting device is mounted between the base frame and the pivot frame and has a torsion spring biasing the pivot frame and the backrest frame to pivot forward. The backrest-adjusting device tightens or loosens the torsion spring to change the resilient force provided to the backrest frame against users' back. Therefore, the chair assembly adapts to differ users well.

Abstract: A weight-responsive chair is provided which has a weight-activated mechanism that resists rearward tilting of a chair back upright while also effecting lifting of a rear portion of the seat to counteract the rearward tilt forces. The weight-activated mechanism includes a spring package connected between the chair frame and back upright which provides for ready mounting of same to the chair frame. Further, the rear seat portion is connected in lifting engagement with the upright but also includes independent suspension for the center of the rear seat portion to allow for independent movement and flexing thereof to improve comfort for the chair occupant.

Abstract: A chair has a link of a chair back, a link of a chair seat, and a link mechanism that pushes up the link of the chair seat when the link of the chair back is pressed to incline rearward, so that the occupant can take the optimum seating posture without being conscious, thus further improving the comfort in the reclined posture.

Abstract: A preference control mechanism is provided that includes a housing, a shuttle, a sub shuttle and at least one resilient member. The housing has a channel. The shuttle has a cavity. The shuttle is moveable within the channel of the housing from a first position to at least one second position. The sub shuttle is moveable within the channel of the housing and is moveable independent of the shuttle. The one or more resilient members have a first end and a second end opposite the first end. The first end is attached to the shuttle and the second end is attached to the sub shuttle. The preference control mechanism is configured for attachment to at least one chair component. Chairs may also be designed to include one or more embodiments of the preference control mechanism.

Abstract: A seat comprising a seat pan (12) and a support structure, wherein the seat pan (12) is pivotally coupled to the support structure (8) about a first pivot axis (pi) provided across substantially the front of the seat pan (12), such that the seat pan (12) may be pivoted about the said first pivot axis (pi) in use, and the angle of the seat pan (12) relative to the support structure (18) may thus be adjusted. The seat further comprises a backrest (14), the backrest being coupled (p2) to substantially the rear of the seat pan (p12). Also provided is pneumatic apparatus for use with a seat, comprising one or more inflatable cushions for supporting a user in use.

Abstract: A mechanism for an office chair having a backrest support which may be pivoted rearwardly. Adjustment of the backrest pivotal motion is accomplished by the mechanism having a base support which may be positioned on a chair column, a seat support, the backrest support which may be pivoted to the rear, and a pre-tensioned spring arrangement for enabling the mechanism to counter or oppose the movement of the backrest support. The seat support and the base support form a movable unit, which may be moved relative to the chair column depending on the weight of a user applying a load to the seat support. Movement of the movable unit causes an adjustment of the pre-tension of the spring arrangement and/or an adjustment of the spring constant of the spring arrangement.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. The tilt control mechanism includes a control plate mounted to the control shaft on which the uprights are mounted, wherein the control plate rotates in combination with the uprights. This control plate is located within the control body and cooperates with a front stop assembly and a back stop assembly to vary the limits of forward and rearward tilting of the seat and back assemblies. Also, the tilt control mechanism includes a pneumatic actuator assembly having fixed and rotatable cam blocks. The rotatable cam block rotates relative to the fixed block such that the rotatable cam block is driven downwardly to depress the control valve of the pneumatic cylinder and thereby vary the height of the seat assembly.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. The tilt control mechanism includes a control plate mounted to the control shaft on which the uprights are mounted, wherein the control plate rotates in combination with the uprights. This control plate is located within the control body and cooperates with a front stop assembly and a back stop assembly to vary the limits of forward and rearward tilting of the seat and back assemblies. Also, the tilt control mechanism includes a pneumatic actuator assembly having fixed and rotatable cam blocks. The rotatable cam block rotates relative to the fixed block such that the rotatable cam block is driven downwardly to depress the control valve of the pneumatic cylinder and thereby vary the height of the seat assembly.

Abstract: A back rest tilting device in a reclining chair formed of fewer parts. A force promoting unit energizes a back rest in an upright direction. A rotating force promoting unit with rubber torsion springs includes a laterally extending pivot shaft rotated integrally with the back rest and an elastic body filled between an outer tube locked to a support body coaxially with the core and the pivot shaft so that the elastic body is elastically deformed when the pivot shaft is rotated about the center axis of the outer tube to impart a returning rotating force to the pivot shaft.

Abstract: An easily operable lock device for a movable member of a chair, the lock device being adapted such that a person sitting on the chair can select lock or unlock position by operating operation means with a load, such as the weight of the person, acting on the movable member and, when the load is removed after the selection of the lock or unlock position, lock or unlock operation is executed. A lock pin provided at a spring receiving member functioning as a movable member, is selectively engaged with and disengaged from engagement holes formed in a reinforcement plate functioning as a support member. The lock device has biasing means for biasing the lock pin toward the lock position when an operation member moved by the operation means is set at a lock reservation position and biasing the lock pin toward the unlock position when the operation member is set at an unlock reservation position.

Abstract: A seating system has a tiltable seat is coupled to a base, which can be coupled to or part of a motor vehicle or other device. The seat can include a seat bracket coupled to the base by a seat tilt pivot configured to permit limited tilting of the seat relative to the base. The seat also can include a footrest mounted to the seat bracket, a horizontal seat cushion and/or a back support coupled to the seat bracket or cushion. The seat is configured to maintain a user's body in a fixed position during tilting throughout the seat's range of tilt angles. A seat adjustment mechanism allows angular adjustment of the seat relative to the base and locks the seat at a fixed tilt angle relative to the base. In some embodiments the seat tilt pivot, that is the axis about which the seat tilts relative to the base, is located approximately vertically below the center of gravity of a loaded seat, thus reducing the force needed to tilt a loaded seat.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. The tilt control mechanism includes a control plate mounted to the control shaft on which the uprights are mounted, wherein the control plate rotates in combination with the uprights. This control plate is located within the control body and cooperates with a front stop assembly and a back stop assembly to vary the limits of forward and rearward tilting of the seat and back assemblies. Also, the tilt control mechanism includes a pneumatic actuator assembly having fixed and rotatable cam blocks. The rotatable cam block rotates relative to the fixed block such that the rotatable cam block is driven downwardly to depress the control valve of the pneumatic cylinder and thereby vary the height of the seat assembly.

Abstract: A tilt tension mechanism for a chair comprises a gear drive mechanism for driving a torsion bar having a drive shaft, a face gear and an actuator shaft with a pinion gear section. The pinion gear section and face gear have cooperating spiral threads which provide for multi-teeth engagement. An isolator bearing is disposed adjacent to the engagement section between said pinion gear teeth and said face gear teeth to support vertical tooth loads.

Abstract: The present invention relates to a mobile joint (1) for a seating construction, especially a chair, for mounting between a seat device and a base, comprising at least two joint elements (10, 30) which are reciprocally restricted pivoted between two extreme positions to allow tilting movement of the seating construction effected by the users weight displacement, comprising two outer joint elements (10, 30) which are pivoted related with a middle joint element (20), wherein the rotational axis (40, 50) between the two joint elements (10, 30) and the middle joint element (20) is displaced in relation to each other in the horizontal direction, whereby the joint (1) may assume a stable tilting position between the two extreme positions.

Abstract: A wheelchair includes a seat and a back that are pivotally supported in two side members and are kinematically interconnected in such manner that an angle between the seat and the back will increase when the back is swivelled backwards about its pivotal support in the side members, which kinematic connection comprises a link connection between the seat and the back. The link connection is in the form of a link arm arranged under the respective pivot supports of the seat and the back so that the distance between the back pivot support and the back link arm connection is less than the distance between the seat pivot support and the seat link arm connection, and that the axis of rotation of the seat through the seat's pivot support in the side members passes essentially through or close to the user's center of gravity.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. The tilt control mechanism includes a control plate mounted to the control shaft on which the uprights are mounted, wherein the control plate rotates in combination with the uprights. This control plate is located within the control body and cooperates with a front stop assembly and a back stop assembly to vary the limits of forward and rearward tilting of the seat and back assemblies. Also, the tilt control mechanism includes a pneumatic actuator assembly having fixed and rotatable cam blocks. The rotatable cam block rotates relative to the fixed block such that the rotatable cam block is driven downwardly to depress the control valve of the pneumatic cylinder and thereby vary the height of the seat assembly.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. This tilt control mechanism includes a tension adjustment assembly having a radial adjustment arm which supports the legs of a pair of coil springs and a cooperating cam block which cooperates with the arm to drive the arm upwardly and downwardly to vary the tilt tension. The cam block is mounted on a threaded shaft and is displaceable sidewardly to either drive the arm and spring legs upwardly or downwardly depending upon the direction of travel of the cam block.

Abstract: A flexible chair that includes a seat member with seat bottom and back rest portions, first and second pairs of legs, and a plurality of cross members. The pair of first legs are pivotly connected to rearward positions of the seat bottom portion and extend downwardly and forwardly from the seat bottom portion. The pair of second legs are pivotly connected to forward positions of the seat bottom portion and extend downwardly and rearwardly from the seat bottom portion, such that the first legs cross the second legs. The plurality of cross members connect the first and second legs together such that the seat member is rearwardly reclinable against a resilient force provided by at least one of the first pair of legs, the second pair of legs and the plurality of cross members.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. This tilt control mechanism includes a tension adjustment assembly having a cam wedge which supports the legs of a pair of coil springs and a cooperating drive block assembly which cooperates with the cam wedge to drive the cam wedge upwardly and downwardly to vary the tilt tension. The drive assembly includes drive blocks mounted on a threaded shaft which are displaceable sidewardly toward and away from each other to either drive the cam wedge upwardly when the drive blocks move together or downwardly when the drive blocks move away from each other.

Abstract: A synchronous office chair comprising a support (1) firmly connected with a supporting column, a seat base (2) articulated on a tilting axis (4) support with a flange (5) and a backrest (3) with a back bracket (6). The back bracket (6) features a first, second and third cam tracks (7, 8, and 9) and engages in an interstice between support (1) and seat base (2). Said seat base (2) with flange (5) and backrest (3) with back bracket (6) are formed to execute a synchronous movement. A first roller bearing (10) is mounted on flange (5) of seat base (2) that engages in the first cam track (7) of back bracket (6) and in which the synchronous movement is guided in first cam track (7). A second roller bearing 11 is mounted on seat base (2) that engages in second cam track (8) of back bracket (6) and in which synchronous movement is guided in second cam track (8).

Abstract: Office chair with improved structure includes: chair back, seat cushion, base frame, L-shaped connecting piece; among others, the vertical part and transversal part of the connecting piece are connected with the chair back and seat cushion respectively; there is an cylinder rod in the middle of the base frame, it coordinates with a handle to realize the lifting and dropping of the seat cushion, the vertical part and transversal part of the connecting piece are directly fixed at the back end of chair back and bottom side of chair seat respectively; in addition, there is a fixing hole coordinating with the top of cylinder rod at the corresponding position of the middle of the seat cushion on the transversal part of the connecting piece.

Abstract: A seating unit comprising a base configured to be positioned on a floor, a torsional energy unit connected to the base, a back connected to the torsional energy unit and a seat rotatably connected to the torsional energy unit. The torsional energy unit biases the back to a forward position. The torsional energy unit further limits angular rotation of the seat between a substantially horizontal seating position and a substantially vertical seating position.

Abstract: A chair is provided that is designed so that the angle of the seat surface portion and the angle of the back surface portion are independent of each other and change, and a user can always take the optimum seated posture. The chair includes a base portion, a first link fixed to a seat and rotatably connected to the base portion, and a second link fixed to a seat back rest and rotatably connected to the first link. The chair also includes a first torque-generating mechanism that generates torque in accordance with the angle of the first link relative to the base portion; and a second torque-generating mechanism that generates torque in accordance with the angle of the second link relative to the first link.

Abstract: A tilt control mechanism for an office chair includes a spring assembly therein which controls the tilt tension on the back assembly. This tilt control mechanism includes a tension adjustment assembly having a radial adjustment arm which supports the legs of a pair of coil springs and a cooperating cam block which cooperates with the arm to drive the arm upwardly and downwardly to vary the tilt tension. The cam block is mounted on a threaded shaft and is displaceable sidewardly to either drive the arm and spring legs upwardly or downwardly depending upon the direction of travel of the cam block.

Abstract: A task chair, including a backrest assembly and a seat assembly pivotally coupled both to one another and to side portions of a fixed yoke member for synchronized movement, in which the seat of the seat assembly moves upwardly and forwardly concurrently with recline of the backrest of the backrest assembly. The chair further includes a tension assembly including an elongate tension member, such as a leaf spring, secured at one end thereof to the yoke member, and a contact member, such as a contact roller, adjustably mounted to the seat assembly. The contact member engages the tension member such that the tension member resists recline of the backrest assembly and concurrent movement of the seat assembly from their initial positions, and also provides a restoring force which tends to move the backrest to its initial upright position and the seat to its initial rearward and lowered position.

Abstract: A seating unit includes a base, a reclineable back, a seat, and a control operably supporting the back and the seat on the base for synchronous movement between upright and recline positions. The control includes a pair of flexible support members and a link that combine to operably support the seat and back for synchronous movement on the base upon recline, which provides ergonomic non-shearing support for a seated user during recline. The back and seat each include perimeter frames, parallel resilient support members extending between side frame sections of the perimeter frames, and covers covering the resilient support members for distributed support and aesthetics. By this arrangement, the flexible member and the link move the one component along a defined path during recline of the back, and the seat and back also provide ergonomic support, both during recline and without recline.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A seat brake apparatus having a small number of components. A pivot member connected to a seat is pivotally supported by a front plate of the battery compartment. A contact plate is connected to the front plate. A torsion spring supported by the front plate has a first end portion contacting the pivot member and a second end portion contacting the contact plate.

Abstract: A seating unit includes a base, a reclineable back, a seat, and a control operably supporting the back and the seat on the base for movement between upright and recline positions. The control includes a pair of flexible support members and a link that combine to operably support the seat and back for synchronous movement on the base upon recline. The flexible support member is stiff in a vertical direction for carrying a combined weight of the one component and of the seated user, but flexible in a horizontal direction to permit a swinging movement of its ends upon recline. The link is rigid and pivoted to the base for movement about a horizontal axis and also pivoted to the one component. By this arrangement, the flexible member and the link move the one component along a defined path during recline of the back.

Abstract: A reclining apparatus is provided between a post and a seat of a chair. The reclining apparatus includes a first joint for attachment to the post, a second joint pivotally connected with the first joint for supporting the seat and a locking device for locking the second joint in one of several reclined positions relative to the casing.

Abstract: A chair has a backrest and a pair of armrests. A pair of support struts for supporting the backrest is connected to a shaft of a base under a seat. The armrest is supported by an arm post. An operating lever is mounted on the upper front end of the arm post. When the backrest is tilted, it is held at a desired angle by pressing up the operating lever.

Abstract: A seating unit includes a seat, a back, a base, and a motion control having a plurality of flexible supports for operably supporting the seat and back on the base. The flexible supports are movable in a generally fore-to-aft direction but stiff in a generally vertical direction, and further the flexible supports have end sections projecting generally outward from said base for operably engaging the seat and/or back, so that when the flexible supports flex in the fore-to-aft direction, they provide for directed movement of the seat and/or the back. In one form, the flexible supports form leaf-spring-like beams with resiliently bendable ends that flex in a slightly angled fore-aft direction to provide a predetermined synchronized path of movement of the seat and back.

Abstract: A chair back is supported on a rigid upright coupled to a horizontal tilt shaft disposed under the front of the chair seat and supported on a control housing fixed to a pedestal. A tension mechanism urges the upright into an upright position. The chair seat is movably supported on the upright by an arrangement which permits the seat to pivot about a transverse horizontal axis positioned adjacent the upper surface of the seat. A control link is pivoted at one end to the control housing, and the other end has lost-motion pivotal connections to the seat frame and the upright. The lost-motion pivotal connection to the seat frame including a spring cooperating between the upright and the seat frame to allow the seat to move relative to the upright.

Abstract: In order to provide a chair that can support near a pelvis or a lumbar portion of a person who sits on the chair irrespective of a body proportion the person or a way to sit, a boundary portion K between a back and a seat is arranged to be transformable or movable and the boundary portion K can be fixed at a position where the boundary K pushes against near the pelvis of the person with an operation from outside

Abstract: This object is attained in a chair comprising a pedestal; a seat support supported thereon via a chair column, said seat support comprising a front and a rear seat support element being connected with one another via a pivot axis extending substantially horizontally; a seat supported on said seat support elements; a backrest secured on said rear seat support element; a longitudinally adjustable energy storing means for mutually adjusting said backrest and said seat, said energy storing means being joined with said seat support elements at a distance from their pivot axis; a spring abutment being arranged pivotably around said pivot axis for adjustably dampening a pivoting movement of said seat support elements relative to one another; an adjusting element extending substantially tangentially relative to said pivot axis and being pivotable around an adjusting element pivot axis for modifying the bias between said spring abutment and one seat support element; and an actuating twist handle connected with said ad

Abstract: A seating unit includes a seat, a back, a base, and a motion control having a plurality of flexible supports for operably supporting the seat and back on the base. The flexible supports are movable in a generally fore-to-aft direction but stiff in a generally vertical direction, and further the flexible supports have end sections projecting generally outward from said base for operably engaging the seat and/or back, so that when the flexible supports flex in the fore-to-aft direction, they provide for directed movement of the seat and/or the back. In one form, the flexible supports form leaf-spring-like beams with resiliently bendable ends that flex in a slightly angled fore-aft direction to provide a predetermined synchronized path of movement of the seat and back.

Abstract: A chair has a seat connected to a support leg in an up and down angularly displaceable manner, elastic elements for propping up a rear end of the seat to a higher position, and a mechanism for limiting position of the seat when the seat seats people; the mechanism has an adjustment rod, a gear turnable together with the adjustment rod, an elastic plate for engaging the gear so as to prevent rotation of the gear when the adjustment rod isn't operated, and eccentric cams for holding the seat at desired position when the chair seats people; the cams can turn together with the adjustment rod, and are each formed with a stopping edge having several sections; thus, the depressed position of the seat, i.e. the position when the seat seats people, is decided by the position of the cams, and the seat can move accordingly when the sitter leans forwards.

Abstract: A seating unit includes a base having a housing and support arms extending laterally on each side of the housing. A back frame is pivoted to the support arms on each side, and a slide slidably engages the housing. A seat-supporting structure includes a crossbar pivotally attached to the slide member at a first pivot location and side frame sections extending rearwardly from ends of the crossbar that are pivotally attached to the lower arms of the back at a second pivot location spaced horizontally from the first pivot locations to define a three-point support for a seat above the housing. A spring is operably coupled to the slide to bias the back and seat toward upright positions.

Abstract: An office-type chair which provides for synchronous differential tilting of the seat and back assemblies, with the seat assembly being constructed such that the front lip thereof does not significantly lift upon rearward tilting. The chair incorporates a tilt control mechanism formed by a control body which secures to the upper end of the chair pedestal and an upright which pivotally connects to the control body about an axis disposed forwardly of the pedestal. A pivot assembly connects the upright and control body together.

Abstract: A chair control mechanism for positioning between the seat and seat support of a chair. The chair control mechanism includes a base section for mounting to a seat support such as an adjustable height cylinder, and a seat mounting section pivotally interconnected with the base section. A seat is mounted to the seat mounting section, and is pivotal about a seat pivot axis. An adjustable position back mounting arrangement is pivotally interconnected with the seat mounting section, and the chair back is engageable with the back mounting section. A variable stop arrangement is interposed between the base section and the seat mounting section, for varying the range of pivoting movement of the seat relative to the seat support. The back can be selectively locked in one of a number of predetermined positions relative to the seat by operation of a variable position back locking arrangement.

Abstract: The chair includes seat and back assemblies interconnected in a four-bar linkage. The chair further includes a tension mechanism comprising a coil spring projecting forwardly from a base and an adjustment linkage which is connected to said coil spring and to a front link of said four-bar linkage. A back linkage end of said adjustment linkage being axially movable along an axis of said coil spring and a front linkage end being vertically movable along said front link to adjust displacement of said adjustment linkage during rearward pivoting of said front link.

Abstract: A chair 1 allowing a person sitting thereon to move a part of the person's body above the waist which corresponds to the backrest of the chair is provided having a backrest portion located behind a seat portion, the backrest portion being divided into backrest upper frames 55 and backrest lower frames 50, wherein a first state which allows the whole backrest frame 5 to incline rearwardly and a second state which allows the backrest upper frames 55 to incline rearwardly relative to the backrest lower frames 50 are assumed, the first state and the second state being switchable to each other.