Masatoshi Iizawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
Abstract: A tennis racket includes a frame that includes a shaft and a looped frame portion, the shaft having a grip formed on one end side thereof, the frame portion being joined to the other end side of the shaft and forming a hitting face with a string being strung across and a plurality of insertion holes that provide communication between an inner peripheral side surface and an outer peripheral side surface of the frame portion and through which the string is inserted. Shock absorbing portions and hard portions are provided in an alternating fashion on at least a part of the outer peripheral side surface of the frame portion. Each shock absorbing portion is formed between insertion holes that are adjacent to each other. Each hard portion is formed between insertion holes that are adjacent to each other and is less elastically deformable than the shock absorbing portion.
Abstract: A tennis racket includes a frame that includes a shaft and a looped frame portion, the shaft having a grip formed on one end side thereof, the frame portion being joined to the other end side of the shaft and forming a hitting face with a string being strung across and a plurality of insertion holes that provide communication between an inner peripheral side surface and an outer peripheral side surface of the frame portion and through which the string is inserted. Shock absorbing portions and hard portions are provided in an alternating fashion on at least a part of the outer peripheral side surface of the frame portion. Each shock absorbing portion is formed between insertion holes that are adjacent to each other. Each hard portion is formed between insertion holes that are adjacent to each other and is less elastically deformable than the shock absorbing portion.