LIBRARY, SEARCH ROOM SEARCHES AND PATENT AND TRADEMARK

DEPOSITOR LIBRARIES
The Scientific and Technical Information Center of the Patent and Trademark Office at Crystal Plaza 3, 2021 Jefferson Davis Highway, Arlington, Va., has available for public use over 120,000 volumes of scientific and technical books in various languages, about 90,000 bound volumes of periodicals devoted to science and technology, the official journals of 77 foreign patent organizations, and over 12 million foreign patents.
A Search Room is provided where the public may search and examine United States patents granted since 1836. Patents are arranged according to the Patent and Trademark Office classification system of over 400 classes and over 120,000 subclasses. By searching in these classified patents, it is possible to determine, before actually filing an application, whether an invention has been anticipated by a United States patent, and it is also possible to obtain the information contained in patents relating to any field of endeavor. The Search Room contains a set of United States patents arranged in numerical order and a complete set of the Official Gazette.
A Files Information Room also is maintained where the public may inspect the records and files of issued patents and other open records.
Applicants, their attorneys or agents, and the general public are not entitled to use the records and files in the examiners' rooms.
The Search Room is open from 8 a.m. to 8 p.m. Monday through Friday except on Federal holidays.
Since a patent is not always granted when an application is filed, many inventors attempt to make their own investigation before applying for a patent. This may be done in the Search Room of the Patent and Trademark Office, and libraries, located throughout the U.S., which have been designated as Patent and Trademark Depository Libraries (PTDL). Patent attorneys or agents may be employed to make a so-called preliminary search through the prior United States patents to discover if the particular device or one similar to it has been shown in some prior patent. This search is not always as complete as that made by the Patent and Trademark Office during the examination of an application, but only serves, as its name indicates a preliminary purpose. For this reason, the Patent and Trademark Office examiner may, and often does, reject claims in an application on the basis of prior patents or publications not found in the preliminary search.
Those who cannot come to the Search Room may order from the Patent and Trademark Office copies of lists of original patents or of cross-referenced patents contained in the subclasses comprising the field of search, or may inspect and obtain copies of the patents at a Patent and Trademark Depository Library. The Patent and Trademark Depository Libraries (PTDLs) receive current issues of U. S. Patents and maintain collections of earlier issued patents and trademark information. The scope of these collections varies from library to library, ranging from patents of only recent years to all or most of the patents issued since 1790.
These patent collections are open to public use. Each of the Patent and Trademark Depository Libraries, in addition, offers the publications of the U.S. Patent Classification System (e. g. The Manual of Classification, Index to the U.S. Patent Classification, Classification Definitions, etc.) and other patent documents and forms, and provides technical staff assistance in their use to aid the public in gaining effective access to information contained in patents. The collections are organized in patent number sequence.
Available in all PTDLs is the Classification And Search Support Information System (CASSIS), computer data base. With various modes, it permits the effective identification of appropriate classifications to search, provides numbers of patents assigned to a classification to permit finding the patents in a numerical file of patents, provides the current classification(s) of all patents, permits word searching on classification titles, abstracts, the Index provides certain bibliographic information on more recently issued patents. Facilities for making paper copies from either microfilm in reader printers or from the bound volumes in paper-to-paper copies are generally provided for a fee.
Due to variations in the scope of patent collections among the Patent and Trademark Depository Libraries and in their hours of service to the public, anyone contemplating the use of the patents at a particular library is advised to contact that library, in advance, about its collection and hours, so as to avert possible inconvenience.