Abstract: A chair seat tilting mechanism comprises a support for mounting to a chair spindle and a lever arm pivotally mounted at a pivot to the support, which lever arm is for mounting to a chair seat. A link arm is pivotally mounted at a pivot to the support and has a cam with a camming end positioned between the lever arm pivot mount and the link arm pivot mount. An extension of the link arm mounts to a chair back such that when a chair occupant leaning back on the chair back, the link arm pivots about the link arm pivot causing the cam to cam lever arm so that it pivots about its own pivot with the support. This results in the chair seat tilting forwardly.

Abstract: A chair armrest adjustment mechanism for an armrest is disclosed. The armrest adjustment mechanism includes a first member, an upstanding second member for mounting to an armrest support member, and a third member having attachment means for fixedly attaching the third member to an armrest pad. The third member and the second member have a pin and slot arrangement to limit the rotational movement of the third member. The first member is pivotally mounted to the second member via a pin such spring cups between the first member and the second member at either side of the pin for biasing the first member to a level orientation with respect to the second member.

Abstract: An improved seat back height adjustment mechanism for a chair is disclosed. The improved height adjustment mechanism includes a U-shaped mounting bracket having a back wall and two side walls. A longitudinal shaft having a handwheel is rotatably mounted in the bracket between the side walls and spaced from the back wall. A seat back support arm is insertable through the bracket between the shaft and the bracket back wall. A back plate provided with a rack and an adjacent planar surface both extending along the length of the back plate is mounted onto the seat back support arm. In one aspect, the shaft is provided with a pinion for engaging the rack and a multi-sided, symmetrical cam adjacent the pinion for locking the shaft against free rotation. When assembled, the rack and the planar surface of the back plate are aligned with the pinion and cam respectively.

Abstract: An improved height adjustment mechanism for a chair seat back is disclosed. The improved height adjustment mechanism includes a U-shaped mounting bracket having a back wall and two side walls. A longitudinal cam having a handle is rotatably mounted in the bracket between the side walls and spaced from the back wall. A seat back support arm is insertable through the bracket between the cam and the bracket back wall. The cam is provided with a plurality of planar faces extending in the longitudinal direction disposed around about a third of the circumference of the cam. The radial length of the line extending perpendicularly from each planar face to the longitudinal axis of the cam increases steadily from one planar face to the next in one direction around the circumference of the cam. This steady increase in distance of the planar faces from the axis of the cam provides a cam action on the seat back support arm when the cam is rotated in one direction with the support arm located between the cam and back wall.

Abstract: There is disclosed a unitary brake for a chair tilt mechanism. The chair tilt mechanism is of the type having a seat back support mechanism biased with respect to a seat tilt mechanism, the seat back support mechanism provided with a mounting bracket and the seat tilt mechanism has a housing attachable to the underside of a chair. The mounting bracket is pivotally attached to the housing adjacent to an end portion thereof. The unitary brake comprises a spindle bracket pivotally mounted in the housing for receiving therein a chair support spindle. The spindle bracket has a plurality of parallel slotted arms extending therefrom with the spindle bracket and the arms being of one piece unitary construction. The unitary brake includes a rear lammal pivotally mounted on the mounting bracket. The rear lammal includes arms interleaved with the spindle bracket arms. The rear lammal arms have slots extending therethrough which are in registration with the slots in the spindle bracket arms.