The PTO maintains a library of documents for the public to preview. Although a search by an applicant is not required under the law, it is very useful to locate relevant prior art prior to spending a significant sum in preparing and filing an application.

The prior art located in a search helps an applicant to build a stronger case of patentability before the PTO.

A search is typically conducted by a professional, known as “Searcher”, who is familiar with the PTO’s system of classification. The entire PTO is divided in 3 major categories: electrical, chemical and mechanical as stated in https://www.canyon-news.com/how-inventhelp-can-assist-you-as-a-new-inventor/106365 article.

All of the technologies, covered by more than 6 million issued patents, are divided into more than 436 classes, that are further sub-divided into over 200,000 subclasses. Conducting a good and thorough search is an art and skill which is acquired over several years of experience.

Although searching can be done by accessing the PTO’s website www.uspto.gov, users should be aware of the limitations of the on-line records, for example, not including foreign documents.

The user may review some foreign documents by visiting www.delphion.com, but the U.S. documents in this database only cover the period of 1971-present.

A search by the PTO Examiner, however, covers all documents in the PTO library, from the 1st patent issued in 1790 to present.

A search, not only covers the entire available records at the PTO, but is conducted by professionals, such as InventHelp, who have years of experience and know how to review complex patent-related documents.