Chair with novel seat construction

A chair comprising:

• a base assembly including a control housing;
• a back frame pivoted to the base assembly at a back pivot for movement between upright and reclined positions;
• seat support structure operably supported on the base assembly and the back frame including a slide member slidably engaging the control housing for generally horizontal sliding movement and including a seat carrier pivoted to the slide member at a front seat pivot and also pivoted to the back frame at a rear seat pivot:
• a spring mechanism position in the control housing, the spring mechanism being operably connected to the slide member and including a spring positioned transversely in the control housing, and further including a lever operably pivoted to the control housing, the lever having one end operably engaging the spring and another end operably engaging the seat support structure;
• and
• a pivot member, the pivot member and the lever having interfacing surfaces, at least one of which is curvilinear so that the arrangement operates like a rack-and-pinion, the pivot member being adjustable to vary a fulcrum point on the lever to adjust a length of a moment arm over which the spring acts to.

A chair comprising:

• a base assembly including a control housing;
• a back frame pivoted to the base assembly at a back pivot for movement between upright and reclined positions;
• seat support structure operably supported on the base assembly and the back frame including a slide member slidably engaging the control housing for generally horizontal sliding movement and including a seat carrier pivoted to the slide member at a front seat pivot and also pivoted to the back frame at a rear seat pivot;
• and
• a seat shell slidably supported on the seat support structure for selective depth adjustment, whereby a depth of the seat shell can be selectively adjusted relative to the back frame.

A chair comprising:

• a base assembly including a control housing with sidewalls defining a track;
• a seat having a front portion with bearings slidably engaging the track and having a rear portion, the seat including a seat shell having a flexibly supported front portion;
• a back pivoted to the base assembly and separately pivoted to the seat for movement between an upright position and a reclined position, the rear portion of the seat being pivoted to the back so that the seat moves forwardly and the seat rear portion moves forwardly and downwardly with a synchronous motion as the back is reclined;
• a spring mechanism positioned in the central housing and operably connected to the seat for biasing the seat rearwardly, the spring mechanism including an extendable/compressible spring positioned in the control housing and a lever pivoted to the control housing and defining a moment arm with the spring for transmitting energy from the spring to the seat to bias the back to the upright position;
• and
• a gas spring operably connected between the front portion of the shell and a remaining portion of the seat adapted to carry the weight of a typical seated adult user, the gas spring being operable to adjust a position of the front portion relative to the remaining portion of the seat.

A chair comprising:

• a base assembly including a control housing with sidewalls defining a track;
• a seat having a front portion with bearings slidably engaging the track and having a rear portion, the seat including a seat shell having a flexibly supported front portion;
• a back pivoted to the base assembly and separately pivoted to the seat for movement between an upright position and a reclined position, the rear portion of the seat being pivoted to the back so that the seat moves forwardly and the seat rear portion moves forwardly and downwardly with a synchronous motion as the back is reclined;
• a spring mechanism positioned in the central housing and operably connected to the seat for biasing the seat rearwardly, the spring mechanism including an extendable/compressible spring positioned in the control housing and a lever pivoted to the control housing and defining a moment arm with the spring for transmitting energy from the spring to the seat to bias the back to the upright position;
• and
• a leaf spring positioned between and resiliently-supporting the front section and a remaining portion of the seat.

A chair comprising:

• a base assembly including a control housing with sidewalls defining a track;
• a seat having a front portion with bearings slidably engaging the track and having a rear portion, the seat including a seat shell and a depth-adjustment structure for adjusting a depth of the seat shell relative to the back;
• a back pivoted to the base assembly and separately pivoted to the seat for movement between an upright position and a reclined position, the rear portion of the seat being pivoted to the back so that the seat moves forwardly and the seat rear portion moves forwardly and downwardly with a synchronous motion as the back is reclined;
• and
• a spring mechanism positioned in the central housing and operably connected to the seat for biasing the seat rearwardly, the spring mechanism including an extendable/compressible spring positioned in the control housing and a lever pivoted to the control housing and defining a moment arm with the spring for transmitting energy from the spring to the seat to bias the back to the upright position.

A chair comprising:

• a base assembly including a control housing;
• a reclineable back frame pivoted to the base assembly for movement between upright and fully reclined positions;
• a seat slidably supported on the control housing and pivotally supported on the back frame;
• and
• a variable back-stop mechanism operably supported on the base assembly for engaging the seat to stop the seat and concurrently stop recline of the back at selected positions prior to reaching the fully reclined position, the variable back-stop mechanism including a seat-engaging member and an actuator lever for adjustably moving the seat-engaging member, the seat-engaging member and the lever including intermeshing teeth for providing slip-free engagement.

A chair comprising:

• a base assembly including a control housing;
• a reclineable back frame pivoted to the base assembly for movement between upright and fully reclined positions;
• a seat slidably supported on the control housing and pivotally supported on the back frame;
• a variable back-stop mechanism operably supported on the base assembly for engaging the seat to stop the seat and concurrently stop recline of the back at selected positions prior to reaching the fully reclined position;
• the variable back-stop mechanism including a movable cam with steps shaped to selectively engage the seat, and further including a spring detent for holding the cam in a selected stopping position where a particular one of the steps is positioned to engage the seat;
• and
• an actuator connected to the cam for rotating the cam to select the particular one step, the actuator including a lever pivoted to the control housing, the lever and the cam including intermeshing teeth.

A chair comprising:

• a base assembly including a control housing;
• a reclineable back frame pivoted to the base assembly for movement between upright and fully reclined positions;
• a seat slidably supported on the control housing and pivotally supported on the back frame;
• and
• a variable back-stop mechanism operably supported on the base assembly for engaging the seat to stop the seat and concurrently stop recline of the back at selected positions prior to reaching the fully reclined position, the variable back-stop mechanism including a movable cam with steps shaped to selectively engage the seat;
• the cam further including an undulated surface adapted to engage a detent for selectively holding the steps in position to engage the seat, and still further including teeth adapted to engage mating teeth on an actuator for operating the cam.

A seat construction for a chair comprising:

• a resiliently-flexible seat shell including a front section configured to comfortably support thighs of a typical seated adult user, a rear section configured to comfortably support buttocks of a seated adult user and to comfortably support a majority of the weight of the seated adult user, and a flexible intermediate section connecting the front and rear sections, the front section being located about midway or forward therefrom on the seat shell and generally forward of the expected location of a seated adult user's hip joint so that the seated adult user's weight is substantially carried by the rear section for most adult users;
• a seat cushion supported on the seat shell;
• a pan-shaped seat carrier supporting the rear section of the shell, the seat carrier including a forwardly-extending section extending under the flexible intermediate section and that is characteristically spaced below and not connected to the flexible intermediate section;
• and
• an adjustable thigh-flex support mechanism operably supporting the front section of the seat shell on the forwardly-extending section of the seat carrier, so that the front section is adjustable relative to the rear section to provide optimal thigh pressure and support to the seated adult user, the adjustable thigh-flex support mechanism including a pretensioned, transverse leaf spring.

A seat construction for a chair comprising:

• a resiliently-flexible seat shell including a front section configured to comfortably support thighs of a typical seated adult user, a rear section configured to comfortably support buttocks of a seated adult user and to comfortably support a majority of the weight of the seated adult user, and a flexible intermediate section connecting the front and rear sections, the front section being located about midway or forward therefrom on the seat shell and generally forward of the expected location of a seated adult user's hip joint so that the seated adult user's weight is substantially carried by the rear section for most adult users;
• a seat cushion supported on the seat shell;
• a pan-shaped seat carrier supporting the rear section of the shell the seat carrier including a forwardly-extending section extending under the flexible intermediate section and that is characteristically spaced below and not connected to the flexible intermediate section;
• and
• an adjustable thigh-flex support mechanism operably supporting the front section of the seat shell on the forwardly-extending section of the seat carrier, so that the front section is adjustable relative to the rear section to provide optimal thigh pressure and support to the seated adult user, the adjustable thigh-flex support mechanism including a bent rod axle and a releasable, lockable gas spring for rotating the bent rod axle and thereafter holding the bent rod axle in a selected orientation.

A seat construction comprising:

• a flexible seat shell including a front section configured to support thighs of a typical seated adult user, a rear section configured to comfortably support thighs of the seated adult user and to comfortably support a majority of the weight of the seated adult user, and a flexible intermediate section;
• a T-shaped seat support pan having a bottom panel defining a full-width rear section and a partial-width front section that has a width less than the full-width rear section and that extends forwardly from a center of the rear section, the full-width rear section being configured to support the rear section of the shell with the partial-width front section extending under and spaced below the front section;
• and
• an adjustable thigh-support mechanism adjustably connecting and supporting the front section on the partial-width front section.

A chair comprising:

• a base assembly including a control housing having at least one up flange and a lubricous bearing supported atop each up flange;
• a back frame pivoted to the base assembly at a back pivot for movement between upright and reclined positions;
• and
• seat support structure operably supported on the base assembly and the back frame including a slide member slidably engaging the lubricous bearing of each up flange for generally horizontal sliding movement and including a seat carrier pivoted to the slide member at a front seat pivot and also pivoted to the back frame at a rear seat pivot.