Abstract: A chair control mechanism is adapted to decrease a likelihood of the mechanism becoming unintentionally disengaged from a locked position. In particular, a control arm has locked position wherein a seat plate is restricted in movement relative to a main bracket and an unlocked position where the movement relative to said main bracket is allowed. A latch bar is biased against the control arm and the control arm is notched such that axial sliding of the control arm into said unlocked position is possible only after providing a force necessary to disengage said latch bar from said notch.

Abstract: A back construction for a seating unit includes a back frame, and a compliant back having a forwardly-protruding lumbar support section that is characteristically flexible and bendable, such that the compliant back can be flexed to a plurality of different convex shapes. Top and bottom connections pivotally connect the compliant back to the back frame. An adjustable force-generating mechanism is operably attached to at least one of the compliant back and the back frame. The force-generating mechanism is constructed to provide an adjustable biasing force that adjustably biases the lumbar support section forwardly for optimal lumbar support for a seated user's back, but the force-generating mechanism characteristically provides the biasing force without forcing a shape change in the compliant back. A vertically adjustable lumbar support is slidably attached to the back shell.

Abstract: The chair mechanism is configured as a so-called synchronizing mechanism in order, in the case of an adjustment in inclination of the rear support (4), to achieve simultaneous, harmonic adjustment of the seat panel (8). The underframe is positioned on a height-adjustable pneumatic spring (13,14). For the synchronized movement, use is made of a mechanical torsion spring, preferably a rubber spring, and a further mechanical spring, preferably a helical spring, is arranged parallel thereto, with accumulative effect in relation to the resistance of the torsion spring. The strength of the torsion spring can be adjusted. The positioning of the axes of rotation (A1-A4) is of considerable importance for the kinematics. The chair can be adjusted from an assembly position, where the springs can be inserted in a state in which they are relieved of stressing, via the vertical position into the inclined position.

Abstract: In a working chair with a seat (12), a back (14) and a lower frame the seat (12) is pivotally connected in the proximity of the front edge with a carrier frame (11) whereas a back support (15) connected with the back (14) is pivotally connected with the carrier frame (11) as well as with the seat (12). The pivot connections are provided for synchronous movement of the seat (12) and the back (14), whereby the seat from a backwards inclining extreme position may be moved to a forwards inclining extreme position and the back (14) synchronously therewith from a backwards inclining position in which it forms a maximum angle with the seat towards a more erect position, while gradually reducing its angle with the seat.

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 synchrotilt chair includes a base, a back, a seat, and a pair of parallel links pivoted to a rear of the base and to a bottom of the back to form a four-bar linkage arrangement. A spring arrangement includes leaf springs that extend between each link and the base to bias the link and in turn the back and seat toward an upright position, with the back and seat pivoting with a synchronous motion upon recline of the back. The base, the back, the seat, and the links are shaped to receive identical chairs along a stacking direction to form a densely nested stacked arrangement for compact storage. The base has a distinctive horizontal U-shaped mid-frame structure defining a plurality of corners, and further having up legs and down legs extending upwardly and downwardly, respectively, from each of the corners, with the pair of links attached to the two rearmost ones of the up legs.

Abstract: A seating unit is provided having a base assembly, a back frame pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back is connected to the back frame at top and bottom locations and is provided with lumbar adjustment for improved lumbar force/support and shape. A seat is provided with seat depth adjustment and with active and passive thigh flex support. The seat includes a front section adjustably and/or flexibly supported on a rear section for optimal comfort while supporting a seated adult user's thighs, With the rear section being configured to carry a majority of the weight of a typical seated adult user. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame.

Abstract: A tiltable chair including a base member (44), a seat (32), a back (34), and a linkage assembly (40) adapted to allow the seat and back to tilt downwardly and rearwardly and to allow pivotal movement of the seat about a pivot axis (52) in substantial alignment with the hip joints of a user. Other aspects of the invention are to provide a vertically adjustable column (42) for supporting the seat of the chair, a support assembly including a frame member (33) having a central opening therethrough and a receptacle formed around the perimeter thereof, a carrier member adapted to fit inside the receptacle, and a membrane of elastic material (210) covering the central opening, and a pair of armrests (36) adapted to be mounted to the chair to allow pivotal movement thereof.

Abstract: A chair tilt mechanism comprising a mechanism support adapted for connection to the seat of a chair and including first means for connection to a chair base and which are pivoted to said mechanism support, second means for connection to a chair back support pivoted to said first means and resilient biasing means which extend between the pivot between the first and second means and the mechanism support, movement of the mechanism support against the biasing causing relative angular movement between the first and second means and relative angular movement of the mechanism support about the pivot between the first means and the mechanism support.

Abstract: A tiltable chair including a housing, a back support pivotally attached to the housing about a first horizontal axis and a seat support pivotally attached to the housing about a second horizontal axis. A leaf spring includes a first end engaging the housing and a second end biasing the back support and seat support in an upward direction. A fulcrum member is moveably supported in the housing and engages a bottom surface of the spring intermediate the first and second ends of the spring. The chair also include an adjustable backrest and armrests slideably mounted on the back support, and a seat slideably mounted on the seat support. A tilt limiter is provided to limit the rearward tilting of the chair. A selector member includes indicia that indicates the setting of the tilt limiter so as to apprise the user of maximum available rearward tilt position of the chair.

Abstract: A seating unit is provided having a base assembly, a back frame pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back is connected to the back frame at top and bottom locations and is provided with lumbar adjustment for improved lumbar force/support and shape. A seat is provided with seat depth adjustment and with active and passive thigh flex support. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame. The moment arm shift adjuster is readily adjustable and includes an overtorque device to prevent damage to components of the energy mechanism.

Abstract: A chair with seat and backrest that oscillate in a synchronized way, comprising:

Abstract: A seating unit is provided having a base assembly, a back frame pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. The pivots for connecting the back frame to the base assembly and for connecting the seat to the back frame permit quick fastenerless assembly by flexing the back frame during assembly. The pivots include rubber elements that permit flexing of a bearing element to prevent binding during rotation when the bearing element is not fully aligned with a pivot axis. A method of assembly including flexing the configured end sections of the back frame, positioning the configured ends adjacent opposite sides of the seat, and releasing the configured end sections so that they engage the seat, is also disclosed.

Abstract: A tiltable chair including a housing, a back support pivotally attached to the housing about a first horizontal axis and a seat support pivotally attached to the housing about a second horizontal axis. A leaf spring includes a first end engaging the housing and a second end biasing the back support and seat support in an upward direction. A fulcrum member is moveably supported in the housing and engages a bottom surface of the spring intermediate the first and second ends of the spring. The chair also include an adjustable backrest and armrests slideably mounted on the back support, and a seat slideably mounted on the seat support. A tilt limiter is provided to limit the rearward tilting of the chair. A selector member includes indicia that indicates the setting of the tilt limiter so as to apprise the user of maximum available rearward tilt position of the chair.

Abstract: A chair has a seat and reclinable back with a pair of armrests pivotably attached to the back. The back includes an outer shell and a mating inner shell. A bolt attaches each armrest to the outer shell and the inner shell is provided with sleeves for receiving the bolts and thereby securing the inner shell to the outer shell. By this arrangement, a single bolt provides for both the pivotable attachment of an armrest as well as for attaching the two mating shells together without any exposed hardware.

Abstract: A tiltable chair including a housing, a back support pivotally attached to the housing about a first horizontal axis and a seat support pivotally attached to the housing about a second horizontal axis. A leaf spring includes a first end engaging the housing and a second end biasing the back support and seat support in an upward direction. A fulcrum member is moveably supported in the housing and engages a bottom surface of the spring intermediate the first and second ends of the spring. The chair also include an adjustable backrest and armrests slideably mounted on the back support, and a seat slideably mounted on the seat support. A tilt limiter is provided to limit the rearward tilting of the chair. A selector member includes indicia that indicates the setting of the tilt limiter so as to apprise the user of maximum available rearward tilt position of the chair.