US 4,906,045 AGranted

Chair control for a pedestal chair having a knee-tilt seat

AssigneeThe Shaw-Walker Company

InventorWilliam K. Hofman

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Abstract

A chair control for a pedestal chair having a knee-tilt seat. An elastomeric torsion spring is offset rearwardly from the tilting axis of the seat. The seat and torsion spring are operatively connected by a cam surface and a cam follower which effectively reduce the restoring force exerted by the torsion spring against the seat as the rearward tilt of the seat increases. A mechanism to adjust the initial restoring torque of the torsion spring provides a large angular twist of the torsion spring with a minimum linear movement of the mechanism. The chair control provides the chair seat with a less than conventional seat angle relative to the horizontal when the chair is unoccupied. A mechanism is provided to enable the occupant to adjust the chair seat to a more conventional seat angle in its unoccupied condition.

Claims11

Dependent claims

A chair control for a pedestal chair having a knee-tilt seat, a chair post tube and a housing extending between said knee-tilt seat and said chair post tube, said chair control including:

a seat support pivot member pivotally mounted on said housing for rotation about a generally horizontal axis located forward of said chair post tube,
means mounted on said seat support pivot member for supporting said seat,
a torsion spring means mounted on said housing rearwardly of said seat support pivot member for rotation about a generally horizontal axis,
cam follower means and an arm having cam surface means, one of said means and said arm attached to one of said seat support pivot means and said torsion spring means, with said cam surface means engaging said cam follower means to bias said seat support pivot member to tilt said seat forwardly,
one of said arms having cam surface means and cam follower means extending non-axially relative to the horizontal axis of rotation of its means,
the engagement between said cam follower means and said cam surface means moving farther away from the horizontal axis of rotation of its means as said support pivot member rotates from its unoccupied position to its fully rearwardly-tilted position to thereby effectively decrease the force exerted by said torsion spring means against said seat support pivot member.

3 more elements

Dependencies are inferred from the claim text.