Combination ergonomic task chair and exercise device

An apparatus that combines a task chair with an exercise device for the lumbar extensors of an occupant of the apparatus, said apparatus comprising:

• a seat for supporting the occupant;
• a seatback having a substantially upright position when said apparatus is in a chair configuration, said seatback movable between a first position and a second position with said apparatus in an exercise device configuration, said first position corresponding to a lumbar flexion position, said second position corresponding to a lumbar extension position;
• and
• a resistance mechanism including a spring assembly and a linkage mechanism, said resistance mechanism applying a seatback force between said seatback and said seat wherein said seatback force decreases as the angle between said seatback and said seat increases wherein said linkage mechanism converts a spring force to said seatback force by decreasing said spring force, said spring assembly biases a first member of said linkage mechanism, said linkage mechanism includes a stationary member, said first member, a second member, and a third member, said first and second members pivotably connected to opposite ends of said stationary member, said third member having a first distal end pivotably attached to said first member at an end of said first member opposite said stationary member, said third member having a second distal end pivotably attached to said second member at an end of said second member opposite said stationary member, said second member attached to said seatback with said seatback moving in tandem with said second member.

An apparatus that combines a task chair with an exercise device for the lumbar extensors of an occupant of the apparatus, said apparatus comprising:

• a seat for supporting the buttocks of the occupant;
• a seatback having a substantially upright position when said apparatus is in a chair configuration, said seatback movable between a first position and a second position when said apparatus is in an exercise device configuration, said first and second positions defining a range of motion from lumbar extension to lumbar flexion;
• and
• a resistance mechanism including a spring assembly and a linkage mechanism, said linkage mechanism connecting said seatback to said spring assembly, said linkage mechanism converting a spring force to a seatback force, said seatback force applied to said seatback, and said seatback force decreasing as the angle between said seatback and said seat increases, said linkage mechanism includes a stationary member, said first member, a second member, and a third member, said first and second members pivotably connected to opposite ends of said stationary member, said third member having a first distal end pivotably attached to said first member at an end of said first member opposite said stationary member, said third member having a second distal end pivotably attached to said second member at an end of said second member opposite said stationary member, said second member attached to said seatback with said seatback moving in tandem with said second member.