Haworth, Inc.

Patrick C Nelson

Richard N Roslund, Jr

Larry Allen Wilkerson

Joel Dral

John Clark

Troy Roark

Steve Simpson

Stephen Joseph Simpson

Robert T Ritt

Douglas M Thole

Manfred Kleinikel

Donald L Cool

Werner H&auml;rtel

Michael D Broekhuis

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. A control mechanism is coupled between the control housing, the upright assembly and the seat frame to permit synchronized tilting of the seat relative to the back in response to tilting of the back about the axis of the tilt shaft.

Chair

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.

Height-adjustment mechanism for a chair

A tilt control mechanism for an office chair includes a spring arrangement which permits forward and rearward tilting of the chair while also urging the chair to a normal upright position. The spring arrangement includes front and rear springs which act in combination such that the upward acting forces acting on the chair can be varied during use. The forces being applied by the front spring are adjusted by a side-actuated tension adjustment mechanism which incorporates a wedge block for adjusting the spring forces. Further, the rear springs provide a variable spring force such that the spring force is maximized when in the normal position but is decreased substantially once the chair is fully reclined. This reduction in spring force allows a user to maintain the chair in the fully reclined position with significantly less force than was required to tilt the chair rearwardly while a sufficient spring force continues to be applied by the front spring to urge the chair to the normal position.

Tilt control for chair

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.

Tilt mechanism for chair having adjustable spring characteristics

An office-type chair which includes a seat assembly and back assembly that are pivotally supported on a chair base or pedestal to support a user thereon. To increase the comfort of the user, the seat assembly is tiltable forwardly and rearwardly by way of a tilt control mechanism while the back assembly thereof is tiltable laterally from side to side, i.e. in the leftward and rightward directions by way of a back torsion mechanism.

Chairback with side torsional movement

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. The activating mechanism includes an activating lever pivotally supported on the arm element, and an activating rod with an upper end which cooperates with the activating lever and a lower end that engages a roller which engages a cam surface of the latch member.

Height-Adjustable chair arm assembly having cam-type adjusting mechanism

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.

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Holland, MI, United States of America

Patrick C Nelson