A chair back structure includes a flexible sheet, the flexible sheet mounted on a support plate so as to adjust a curvature of a chair back by changing a curvature between two ends of the flexible sheet. A fixing segment of the flexible sheet is connected with an end of the support plate. The support plate includes two tilted abutting tabs configured to abut against with a moving segment of the flexible sheet in a sliding path, such that when the moving segment is operated to change the curvature of the flexible sheet, the moving segment slides along the two tilted abutting tabs forward or backward so as to produce a displacement, thus enhancing a bending deformation of the chair back.

An ergonomic chair includes a back component and a seat component. The back component includes an upper back support, a lower back support, a seat back frame that is elastically deformed under traction or squeezing, and a locking mechanism for maintaining positions of the above three components to be relatively fixed. The lower back support is connected to the seat component through a connecting rod. A lower end of the upper back support is rotatably connected to an upper end of the lower back support. Upper and lower ends of the seat back frame are respectively hinged on an upper portion of the back support and the lower portion of the lower back support.

A seating structure includes a body support member having laterally spaced opposite sides and longitudinally spaced ends. The body support member has a curvature in least one of the lateral and longitudinal directions, wherein the curvature is changeable between at least first and second configurations. The body support member includes a shape memory material extending in at least one of the lateral and longitudinal directions, wherein the shape memory material is attached to the body support member at two spaced apart locations. The shape memory material is contractible between at least a non-energized state and an energized state in response to an application of energy. The shape memory material biases the flexible body support member between the first and second configurations when the shape memory material is contracted to the energized state. Other office systems incorporating shape memory materials are also provided.

A system of controlling various actuators associated with human support surfaces is disclosed. Such a system is made up of a support surface, a controller, and an actuator. The system may optionally include batteries, a means of charging the batteries, and a graphical user interface as well as a communication link between the graphical user interface and the support surfaces. The actuators are capable of altering contour and/or firmness, of a support surface, they may be vibrational or heating/cooling in nature, and they may also alter the overall relative position of a support surface.

An adjustable chair support system includes a first seat back support member spaced from a second seat back support member, and a seat back tensioning assembly that extends between the first and second seat back support members. The seat back tensioning assembly includes a carrier coupled to the first seat back support member, the carrier including an adjustable tension member and a first guide member, a pair of second guide members coupled to the second seat back support member, and a cable extending from the adjustable tension member into engagement with one of the pair of second guide members, with the first guide member, with the other of the pair of second guide members, and then returning to the adjustable tension member.

An adjustable chair support system includes a first seat back support member spaced from a second seat back support member, and a seat back tensioning assembly that extends between the first and second seat back support members. The seat back tensioning assembly includes a carrier coupled to the first seat back support member, the carrier including an adjustable tension member and a first guide member, a pair of second guide members coupled to the second seat back support member, and a cable extending from the adjustable tension member into engagement with one of the pair of second guide members, with the first guide member, with the other of the pair of second guide members, and then returning to the adjustable tension member.

A seat assembly having a seat back and a thoracic support mechanism. The thoracic support mechanism may have a flex plate that may be movably disposed on a support member of the seat back frame. A first actuator may flex the flex plate. A second actuator may actuate the flex plate along the support member.

An adjustable chair support system includes a first seat back support member spaced from a second seat back support member, and a seat back tensioning assembly that extends between the first and second seat back support members. The seat back tensioning assembly includes a carrier coupled to the first seat back support member, the carrier including an adjustable tension member and a first guide member, a pair of second guide members coupled to the second seat back support member, and a cable extending from the adjustable tension member into engagement with one of the pair of second guide members, with the first guide member, with the other of the pair of second guide members, and then returning to the adjustable tension member.

A lumbar support assembly, a backrest assembly, and a method for manufacturing a lumbar support assembly are provided. The lumbar support assembly includes a plate member configured to flex and conform to a lumbar region of a user, the plate member includes a mesh structure including a plurality of interconnected elements. The interconnected elements define a plurality of Y-shaped voids therebetween, and each interconnected element includes an edge portion thinner than a center portion. The lumbar support assembly also includes a frame member supporting the plate member.

A chair back assembly includes a frame assembly including a pair of slots extending through the frame assembly, a first location positioned between the pair of slots, and a pair of second locations located outward of an outer periphery of the frame assembly, and a vertically adjustable lumbar assembly configured to support a lumbar area of a seated user and including a central portion and a pair of end portions slidably engaging the central portion, the central portion located in the first location and the end portions located in the second locations, wherein the pair of end portion are slidably moveable within the slots between a first position and a second position that is different than the first position.