Abstract: A seating structure includes a support structure, a seat supported by the support structure and a backrest pivotally connected to the support structure. The seat includes a front and rear. The backrest is positioned adjacent the rear of the seat. The backrest includes a frame having a pair of bow-shaped side members. Each of the side members has a lower section and an upper section. The upper sections extend from the lower sections so as to form a pair of first bowed sections at substantially a lumbar region of the backrest. A flexible membrane is attached to and extends between the side members. The flexible membrane has a second bowed section corresponding to the first bowed sections of the side members. A method of using the seating structure is also provided.

Abstract: A seating structure includes a support assembly for supporting the body of a user. The support assembly includes a frame member defining an opening and having a channel formed around at least a portion of a perimeter of the opening and an expandable carrier member expandable between at least a first and second configuration. The carrier member is inserted into the channel when expanded to the second configuration. A membrane of elastic material covers the central opening. The membrane has an edge, at least a portion of which is attached to the carrier member. The membrane is stretched a desired amount as the carrier member is expanded between the first and second configurations. A method of assembling a seating structure is also provided.

Abstract: A height and pivot-adjustable office chair arm assembly with an arm rest that can be raised to different vertical positions by actuation of a gas cylinder and having a shroud surrounding and vertically movable with respect to at least a portion of an arm support that is hollow and surrounds the gas cylinder such that the shroud is vertically movable in relation to at least a portion of the arm support. The shroud is connected to the gas cylinder at an upper end for vertical movement by the gas cylinder. An arm rest pivot support is attached only to the shroud and receives the arm rest assembly and enables the arm rest assembly to pivot in a horizontal plane thereby allowing the arm rest assembly to assume any selected rotational position.

Abstract: A backrest for a chair comprising a frame, a membrane and a back support member. The membrane, at least a portion of which is transparent, is attached to the frame and has a first body-contacting surface and an opposite second surface. The back support member is attached to the frame and has a support surface. At least a portion of the support surface contacts the second surface of the membrane, and at least a portion of the back support member is visible through the membrane from the first body-contacting surface thereof. In another aspect, a backrest for a chair comprises a frame having a pair of side members, wherein each of the side members has a lower section and an upper section. The upper section extends rearwardly and outwardly from the lower section so as to form a bowed section therewith. A flexible membrane is attached to and extends between the side members, and has a bowed section corresponding to the bowed section of the side members.

Abstract: A height and pivot-adjustable office chair arm assembly with an arm rest that can be raised to different vertical positions by actuation of a gas cylinder and having a shroud surrounding and vertically movable with respect to at least a portion of an arm support that is hollow and surrounds the gas cylinder such that the shroud is vertically movable in relation to at least a portion of the arm support. The shroud is connected to the gas cylinder at an upper end for vertical movement by the gas cylinder. An arm rest pivot support is attached only to the shroud and receives the arm rest assembly and enables the arm rest assembly to pivot in a horizontal plane thereby allowing the arm rest assembly to assume any selected rotational position.

Abstract: A seating structure having a fabric with a weave pattern for supporting the body of a user. The fabric includes a plurality of strands of multifilament yarn and a plurality of monofilaments running generally perpendicular to the strands. At least some of the monofilaments are arranged in pairs. The monofilaments in each pair weaving alternatively above and below some adjacent strands and crossing over each other between other adjacent strands.

Abstract: A seating structure includes a support assembly for supporting the body of a user. The support assembly includes a frame member defining an opening and having a channel formed around at least a portion of a perimeter of the opening and an expandable carrier member expandable between at least a first and second configuration. The carrier member is inserted into the channel when expanded to the second configuration. A membrane of elastic material covers the central opening. The membrane has an edge, at least a portion of which is attached to the carrier member. The membrane is stretched a desired amount as the carrier member is expanded between the first and second configurations. A method of assembling a seating structure is also provided.

Abstract: A seating structure includes a backrest having a top and bottom and includes a frame. The frame includes a pair of spaced apart side members defining an opening therebetween. Each of the side members has a length. A flexible membrane extends between and is attached to the side members across the opening. An armrest is moveably mounted to each of the side members. Each of the armrests is adjustably moveable along at least a portion of the length of the side members between at least a first position and a second position. The first position is closer to the bottom of the backrest than the second position. A method of adjusting the seating structure is also provided.

Abstract: A seating structure includes a support structure, a seat supported by the support structure and a backrest pivotally connected to the support structure. The seat includes a front and rear. The backrest is positioned adjacent the rear of the seat. The backrest includes a frame having a pair of bow-shaped side members. Each of the side members has a lower section and an upper section. The upper sections extend from the lower sections so as to form a pair of first bowed sections at substantially a lumbar region of the backrest. A flexible membrane is attached to and extends between the side members. The flexible membrane has a second bowed section corresponding to the first bowed sections of the side members. A method of using the seating structure is also provided.

Abstract: A tiltable chair including a base member (44), a seat (32), a back (34), and a linkage assembly (40) adapted to allow the seat and back to tilt downwardly and rearwardly and to allow pivotal movement of the seat about a pivot axis (52) in substantial alignment with the hip joints of a user. Other aspects of the invention are to provide a vertically adjustable column (42) for supporting the seat of the chair, a support assembly including a frame member (33) having a central opening therethrough and a receptacle formed around the perimeter thereof, a carrier member adapted to fit inside the receptacle, and a membrane of elastic material (210) covering the central opening, and a pair of armrests (36) adapted to be mounted to the chair to allow pivotal movement thereof.

Abstract: A backrest for a chair comprising a frame, a membrane and a back support member. The membrane, at least a portion of which is transparent, is attached to the frame and has a first body-contacting surface and an opposite second surface. The back support member is attached to the frame and has a support surface. At least a portion of the support surface contacts the second surface of the membrane, and at least a portion of the back support member is visible through the membrane from the first body-contacting surface thereof. In another aspect, a backrest for a chair comprises a frame having a pair of side members, wherein each of the side members has a lower section and an upper section. The upper section extends rearwardly and outwardly from the lower section so as to form a bowed section therewith. A flexible membrane is attached to and extends between the side members, and has a bowed section corresponding to the bowed section of the side members.

Abstract: A seat for a chair comprises a frame comprising spaced apart side members with inboard edges defining an opening therebetween. Each of the side members has a support wall extending upwardly from the inboard edges. A membrane extends between and is attached to the side members and covers at least a portion of the opening. At least a portion of the support walls extend upwardly from and are positioned above at least a portion of an upper body-supporting surface of the membrane. In another aspect, the seat has a frame and a flexible membrane secured to the frame, with the membrane and frame defining an upper body-supporting surface comprising substantially concave side portions and a substantially convex front portion. In yet another aspect, the seat comprises a frame comprising a front portion and a flexible membrane connected to the front portion. A cushion is disposed between the front portion of the frame and the membrane.

Abstract: A method of making an office chair by stretching a membrane in a stretching machine and retaining the stretched membrane on a loom. The loom, with the retained stretched membrane, is removed from the stretching machine and positioned between molds of a molding machine, wherein the molding machine is used to form a carrier member to hold a portion of the stretched member by injecting a material into a cavity formed between the molds to form a part of the chair.

Abstract: A support assembly for supporting the body of a user in a chair including a frame member having a channel. A prestretched membrane comprising an elastic material is attached to a carrier member, which is inserted in the channel. A method is also provided for manufacturing a chair including a frame member, a membrane and a carrier member.

Abstract: A membrane for a seating structure including a plurality of groups of at least two adjacent and parallel strands of multifilament yarn and a plurality of monofilaments arranged in generally perpendicular interlocking relationship with the strands. The monofilaments weave alternatively above and below the adjacent strands in each group. A plurality of pairs of the monofilaments hold the groups of strands in place by having the monofilaments in each pair cross over between each group of strands. In one aspect, the membrane is attached to a frame member such that the plurality of groups of strands are oriented in the longitudinal direction of the frame member and the monofilaments are oriented in the lateral warp direction of the frame member. In another aspect, the seating structure includes the frame member and attached membrane.

Abstract: An apparatus for controlling the tilt range of a chair and the resistance to tilting of the chair including a torsion spring mounted to an axle, a tilt rate adjustment mechanism, a forward tilt limiter and a rearward tilt limiter. The tilt rate adjustment mechanism includes an outer sleeve member mounted to the spring. An arm extends radially outward from the sleeve and operably engages a block member threadably attached to a screw. A first and second gear member are actuated to rotate the screw so as to move the block member which thereby moves the arm a desired amount to adjust the initial return torque of the spring. The forward tilt limiter includes an arm extending outwardly from the axle. The arm operably engages a pivot member pivotally attached to a tilt control housing. The rearward tilt limiter also includes an arm extending outwardly from the axle. The arm operably engages a cam member pivotally attached to the tilt control housing.

Abstract: A vertically adjustable column for supporting a seat of a chair. The column includes an outer guide tube mounted to a support stand, an intermediate telescoping tube slidably positioned with the guide tube and an inner telescoping tube slidably positioned within the intermediate tube. An upper portion of the inner telescoping tube is connected to the seat. A gas spring includes a cylinder mounted within the inner tube, a piston rod extending outwardly from the cylinder and a control pin assembly mounted to an upper portion of the cylinder. The piston rod is connected to the guide tube and is extensible between a collapsed position in which the cylinder and inner tube are substantially within the intermediate tube and the intermediate tube is substantially within the guide tube, and a raised position in which a portion of the cylinder and inner tube extend outwardly from the intermediate tube and a portion of the intermediate tube extends outwardly from the outer guide tube.