My grandfather is the inventor. My late father and his son told me my grandfather sold the patent, but I don't see that someone else holds it. Could you tell me more about it?
Lee John B is listed as inventor and original assignee of the patent. The inventor is the person who made the invention. The assignee is the person or organization that owns the economic rights to the patent — primarily the right to demand money if someone uses the invention. Assigneeship can be sold and is very often conferred to the employer by contract when the invention was made as part of a job.
Economic rights last about 20 years, depending on the country and exact circumstances. This is called the term of a patent. For this patent, the term expired in 1984, 20 years after filing. Therefore the invention has been in the public domain for 30 years. At this point, there are no rights to be had.