The Centripetal Spring Chair or Armchair was a 19th-century American office chair, and one of the first modern designs for office chairs. Designed in 1849 by the American inventor Thomas E. Warren (b. 1808), the chair was produced by the in Troy, New York. Made of cast iron and varnished steel with wood and velvet upholstery, it measured 107 × 61 × 71 centimeters with headrest and armrests, and had a seat height of 48 centimeters.