US patents become publications for all purposes, i.e. both for testing novelty and obviousness, as soon as they are granted back to the date of first application in the US Patent Office. An important aspect of US practice is a stringent requirement that the applicant disclose to the US Patent Office everything that is pertinent to the invention. It is vital that the inventor set out all the information with which he or she is acquainted and also any information which might bear on the practicality of the invention. It is also necessary to disclose the best mode of carrying out the invention so one cannot conceal a commercially important aspect. Finally, once granted, US patents are not subject to opposition although it is possible to institute a re-examination procedure of a US patent if publications are found which are pertinent to the invention as claimed.
Maintenance fees are payable before the end of the fourth, eighth and twelfth years.
Because of the rather longer gaps than in most countries, it can sometimes be easy in the absence of an adequate record system to overlook the necessity of such maintenance. A US patent lasts for 17 years from grant for present patents. For applications after 8 June 1995 it will be 20 years from application date. In looking for advice on US laws remember that the UK Chartered Patent Agents have to study US patent law for the purposes of the UK examinations. A List of US attorneys located in Europe can be obtained from the US Patent Office or the US Embassy in London.