Abstract A chair control for tilting and posture wherein the control has a first frame member and a second frame member pivotally attached together by a first pivot. The first frame member is mountable on the top end of the chair post which is carried by the chair base. The first frame member is pivotally connected, by a second pivot, to a seat-support member, adjacent the front end thereof allowing the support member to have pivotal movement. The second frame member, in addition to being pivotally connected to the first frame is also pivotally connected to the seat-support member, adjacent the rear portion, by a third pivot. A coiled torsion spring biases the second frame against movement from and return to a normal position to permit pivotal movement of the second frame relative to the first frame. A chair seat is pivotally fastened to the first frame for limited up and down tilting on its pivot. The chair back is mounted in an upright position to the second frame for limited backward movement against the tension of the torsion spring. When the chair back is tilted backward the seat is caused to pivot so that the seat will be tilted downwardly toward the back to a slight extent.
A chair comprising a chair seat and a chair back relatively tiltable about a horizontal axis, a chair control including support means carrying said chair seat, a first frame member, pivot means connecting the first frame member to said support means for relative pivotal movement between the first frame member and said support means; a second frame member having one end attachable to said chair back; a pivot pin pivotally connecting an opposite end of the second frame member to an adjacent end of the first frame member to permit pivotal movement between the first and second frame members; contact means on said second frame member disposed at a side of said pivot pin adjacent said adjacent end of said first frame member engageable with said support means when the second frame member is pivoted in a first direction in response to backward tilt of the chair back for pivoting said support means and said chair seat in an opposite direction thereby at least at times effecting simultaneous pivoting of said chair seat and chair back, and spring-biasing means urging the first and second frame members to a normal position at which said spring-biasing means resists backward tilting of the chair back under the influence of an external force effectively applied thereto.
Claim 2
Dependent Claim
212 words
A chair comprising a chair seat and a chair back relatively tiltable about a horizontal axis, a chair control including support means carrying said chair seat, a first frame member, pivot means connecting the first frame member to said support means for relative pivotal movement between the first frame member and said support means; a second frame member having one end attachable to said chair back; a pivot pin pivotally connecting an opposite end of the second frame member to an adjacent end of the first frame member to permit pivotal movement between the first and second frame members; contact means on said second frame member disposed at a side of said pivot pin adjacent said adjacent end of said first frame member engageable with said support means when the second frame member is pivoted in a first direction in response to backward tilt of the chair back for pivoting said support means and said chair seat in an opposite direction thereby at least at times effecting simultaneous pivoting of said chair seat and chair back, and spring-biasing means urging the first and second frame members to a normal position at which said spring-biasing means resists backward tilting of the chair back under the influence of an external force effectively applied thereto.
Claim 3
Dependent Claim
56 words
A chair as defined in claim 1 wherein said support means is defined by a pair of spaced-apart rigid supports carrying said chair seat, said first frame member including means for mounting the same upon a top end of an associated vertical post, and stop means for limiting the pivotal movement of said second frame member.
Claim 4
Dependent Claim
66 words
The chair as defined in claim 2 wherein said biasing means is a torsion spring carried by the first frame member and being coiled around said pivot pin in coaxial relation thereto, said spring having one end secured to and acting on said first frame member and its other end engaging the second frame member to resist pivotal movement between said first and second frame members.