Platform Rockers like this are often called “Patent Furniture” because quite often components or designs were protected from reproduction by other furniture makers by the original designer applying for patent protection. Platform rockers like this one generally postdate 1870, many will have patent dates on the spring rocker mechanism to indicate the earliest date of production. The majority of them were produced during the last quarter of the 19th Century. Depending on the country of origin this patent protection could last for over 15 years.
Values for them peaked during the 1990's, along with the demand for other Victorian decorative items. Demand since then has been in decline along with values for them. Chairs of this type are neither rare nor very valuable, they often sell for more fully restored than in good original condition. Currently a comparable one at auction would sell in the $150.00- $300.00 range.