Abstract: A synchrotilt mechanism for a chair to provide improved control over the relative but synchronized tilting of the back and seat during tilting. The chair back is supported on a rigid upright assembly including lower lever arms which project under the chair seat and are coupled at forward ends to a horizontal tilt shaft which is disposed under the front of the chair seat and is supported on a control housing fixed to the upper end of the base pedestal. A tension control mechanism is coupled between the tilt shaft and the control housing for normally urging the upright arrangement, and the chair back, into an upright position. The chair seat is movably supported on the lower lever arms by a support arrangement which permits the chair seat to pivot relative to the upright assembly about a generally transverse horizontal axis which is preferably slightly below the upper surface of the seat when the latter is in a nondeformed condition, i.e., the seat is not occupied.

Abstract: A synchrotilt mechanism for a chair to provide improved control over the relative but synchronized tilting of the back and seat during tilting. The chair back is supported on a rigid upright assembly including lower lever arms which project under the chair seat and are coupled at forward ends to a horizontal tilt shaft which is disposed under the front of the chair seat and is supported on a control housing fixed to the upper end of the base pedestal. A tension control mechanism is coupled between the tilt shaft and the control housing for normally urging the upright arrangement, and the chair back, into an upright position. The chair seat is movably supported on the lower lever arms by a support arrangement which permits the chair seat to pivot relative to the upright assembly about a generally transverse horizontal axis which is preferably slightly below the upper surface of the seat when the latter is in a nondeformed condition, i.e., the seat is not occupied.

Abstract: A height adjustment mechanism in a chair operates automatically by raising and lowering a chair component such as a chair back. The height adjustment mechanism is provided on a chair back or other chair support and includes a gear which engages a rack member that is vertically movable relative thereto in response to movement of the chair back. A locking member is provided which engages the gear to prevent downward movement of the chair back while still permitting upward movement of the chair back. A disengagement member also is provided to separate the gear and the locking member and maintain the gear in a disengaged position that permits lowering of the chair back.

Abstract: A height adjustment mechanism in a chair operates automatically by raising and lowering a chair component such as a chair back. The height adjustment mechanism is provided on a chair back or other chair support and includes a gear which engages a rack member that is vertically movable relative thereto in response to movement of the chair back. A locking member is provided which engages the gear to prevent downward movement of the chair back while still permitting upward movement of the chair back. A disengagement member also is provided to separate the gear and the locking member and maintain the gear in a disengaged position that permits lowering of the chair back.

Abstract: An office chair includes a tilt control mechanism which connects a seat assembly to a base. The tilt control mechanism defines a pivot connection between the seat assembly and the base whereby the seat assembly effectively pivots about a pivot point in any direction extending radially from the pivot point. The tilt control mechanism includes an annular elastomeric ring which resists multi-directional tilting and biases the seat assembly to a neutral position. The elastomeric ring has a contact area on which the tilting moment of the seat assembly acts which contact area can be selectively varied to adjust tilting resistance.

Abstract: A chair having height-adjustable arm assemblies mounted adjacent opposite sides of a seat. Each arm assembly includes an elongate armrest connected to an upper end of an arm upright. The arm upright includes a vertical support segment which has a guide bore therein. The armrest includes a vertically elongate slide tube and a horizontally elongate arm element connected to an upper end of the slide tube. A lower end of the slide tube is movably mounted within the guide bore. A latch arrangement permits the slide tube to be positioned relative to the support segment at any one of a plurality of height positions. The latch arrangement includes a cartridge assembly received within a window defined in a vertical wall of the slide tube. The cartridge assembly includes a latch member movably supported within a box-like housing and movable to engage one of a series of latching notches. An activating mechanism functions to move the latch member between latching and release positions.

Abstract: A load-released height-adjusting mechanism coacting between the relatively rotatable spindle and pedestal of a chair. The mechanism employs a split nut threadably engaged with the pedestal. A wedge is continuously spring-urged into engagement with the nut for urging the sectors thereof radially for engagement with the threaded pedestal. The wedge is loaded downwardly by the spindle when the chair seat is occupied to cause the nut sectors to lockingly and nonrotatably engage the pedestal to permit free rotation of the spindle without effecting height adjustment. The wedge is not acted on by the spindle when the latter is in a raised position due to the chair seat being unoccupied, but the frictional treaded engagement between the pedestal and nut prevents free-wheeling of the chair while permitting manual rotation of the chair seat and nut to effect height adjustment.