Patents by Inventor Arthur S. Thomas

Arthur S. Thomas 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).

  • Lubricant compositions with metal-free antiwear or load-carrying additives and amino succinate esters
    Patent number: 5254272
    Abstract: Lubricant compositions especially useful as hydraulic fluids contain a metal-free anti-wear or load-carrying additive containing sulphur and/or phosphorus and an amino succinate ester as corrosion inhibitor. Such compositions are free from heavy metal and have improved environmental acceptability where heavy metals are to be avoided, e.g. in agriculture. The lubricant base stock may be a biodegradable natural oil.
    Type: Grant
    Filed: November 2, 1992
    Date of Patent: October 19, 1993
    Assignee: Ethyl Petroleum Additives Limited
    Inventors: David K. Walters, Arthur S. Thomas