Back construction with flexible lumbar

A back construction for a seating unit comprising:

• a back frame;
• a back support;
• and
• at least two connections operably connecting the back support to the back frame for movement relative to the back frame;
• the at least two connections including a pair of spaced-apart cooperating links on each side, each with a first end connected to a lower portion of the back frame and each with a second end connected to a lower portion of the back support, the cooperating links being positioned and adapted to constrain a body-supporting portion of the back support to move along a predetermined path that provides continuous lumbar support to a seated user and, while moving along said path the body-supporting portion, defining a predetermined vertical angle corresponding to each location along the predetermined path;
• wherein the first and second ends of each of the first and second links define four axes of rotation, the four axes defining a first pattern that is different than a second pattern where the second pattern defines a parallelogram linkage arrangement.

A back construction for a seating unit comprising:

• a back frame;
• a back support;
• and
• at least two connections operably connecting the back support to the back frame for movement relative to the back frame;
• the at least one connection including a pair of spaced-apart cooperating links each with a first end pivotally connected to the back frame and each with a second end pivotally connected to the back support, the cooperating links having different lengths and being positioned and adapted to constrain a body-supporting portion of the back support to move along a predetermined path that provides continuous lumbar support to a seated user and, while moving along said path the body-supporting portion, defining a predetermined vertical angle corresponding to each location along the predetermined path.

A seating unit comprising:

• a base;
• a seat;
• a back frame;
• and
• a back support including at least one top connection operably supporting the back support on the back frame and at least one bottom connection operably supporting the back support on one of the base and the back frame, the back support having a flexible lumbar region between the top and bottom connections, the bottom connection being constructed to direct movement of a lower edge of the back support generally downwardly along a predetermined path as the lumbar region is flexed from a forwardly-protruding shape toward a more planar shape while providing continuous lumbar support to a seated user during changes between the shapes, the bottom connection being positioned rearward of front surfaces along sides of the lower edge, wherein the at least one bottom connection includes a pair of links on each side forming at least one four-bar linkage arrangement.

A seating unit comprising:

• seat;
• a back frame;
• a back support operably connected to the back frame at an upper connection and a lower connection, the back support having a flexible lumbar region generally between the upper and lower connections;
• and
• the lower connection including a linkage arrangement having at least a pair of cooperating links near each side, each link pivoted to the back frame at one end and pivoted to the back support at another end so as to be adapted to constrain at least the lower portion of the back support to move along a predetermined path that provides continuous lumbar support to a seated user as the lumbar region is moved.

A seating unit comprising:

• a seat;
• a back frame;
• a back support connected to the back frame at an upper connection and a lower connection, the back support having a lumbar region generally located between the upper and lower connections;
• and
• the lower connection including a constraining mechanism located rearward of the forward face of the back support and adapted to constrain at least the lower portion of the back support to move and rotate along a predetermined path that provides continuous lumbar support to a seated user as the lumbar region is moved, wherein the lower connection includes a four-bar linkage with four defined axes of rotation.

A back construction for a seating unit comprising:

• a back frame;
• a back support;
• and
• at least one connection operably connecting the back support to the back frame for movement relative to the back frame;
• the at least one connection including a pair of spaced-apart cooperating links each with a first end pivotally connected to the back frame and each with a second end pivotally connected to the back support, the cooperating links being positioned and adapted to constrain a body-supporting portion of the back support to move along a predetermined path that provides continuous lumbar support to a seated user and, while moving along said path the body-supporting portion, defining a predetermined vertical angle corresponding to each location along the predetermined path, wherein the back support comprises a shell having a flexible lumbar region.