Patent 5209473 Issued on May 11, 1993. Estimated Expiration Date: May 11, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
A set of iron-type golf clubs including a predetermined number of clubs is disclosed with each club including a hosel portion with a shaft operatively inserted therein and a blade portion attached to the hosel portion. The blade includes a substantially planar face portion which is generally oval in shape, a back portion which is generally oval in shape and is disposed opposite the planar face portion. The back portion includes a cavity which is generally oval in shape. A torsion ring which is generally oval in shape completely surrounds the cavity and distributes the weight thereof around the perimeter of the cavity.