Patents
Tips and tricks for online searching historical patents, from before 1970, with a focus on old calculating devices.
For recent patents and patent applications better online search tools and strategies are available.
In the mid 1990s I started collecting mechanical calculators. It seemed a good idea to use patents to get more information on these machines. In the still fledgling World Wide Web a few patent numbers of old calculators, such as the Curta, were listed. There was also a rudimentary website of the United States Patent and Trademark Office (USPTO, http://patft.uspto.gov/) where patents from 1976 and later could be found. That was not very useful for mechanical calculators. Fortunately I lived close to the library of the University of Delaware, which doubles as a state library and therefore contains a huge collection of federal government documents. This library had microfilms of U.S. patents. That way I could make photocopies of interesting patents if I knew their number. At that time I bought a Comptometer, which had a shield with some of patent dates, but no numbers. Since U.S. patents are published only once a week, on a Tuesday,[1] that meant that I'ld have to look through a lot of patents of one publication day before I would have found the Comptometer patent. With bad luck, the patents of one day were taking up several film spools, each of which had to be requested at the library desk. Fortunately, next to the microfilm readers was a shelf with the paper version of the Official Gazette for Patents, in which a summary of patents is given per day and subject. With the Gazette patent numbers could be identified much faster.
I scanned and OCR'd a few interesting patents and placed it on my brand new website "Original Documents on the History of Calculators". This attracted the attention of a few European collectors who asked if I could add copies of other patents. It threatened to get out of hand...
U.S. patents online
Fortunately the USPTO was steadily improving its online presence. Images in TIFF format of all old patents were put on the web. They could only be found by Patent Number and Classification, and not by date, title, inventor or text. The Comptometer had already shown that the ability to search by date would have been convenient. So I made a tool that could estimate a patent number based on the publication date. The tool converted this estimate into a query of the USPTO database. When you added a classification to the query (for calculating instruments: 235/$), and the patent was issued in a time where not many patents were issued, you quickly located the required patent. Years later, Google came up with its own full-text search engine for U.S. patents, and relieved us from of those inconvenient TIFFs.
Europe
In the late nineties, I returned to the Netherlands. The library of the Dutch Patent Office in the European Patent Office in Rijswijk took over the role of the University of Delaware Library. It has paper versions of European Patents and Gazettes. In a French Gazette I found a reference to a French patent from 1855 for a "nouvelle machine à calculer et à imprimer des tables de mathématiques" granted to "Nits, comte de Barck". I did not recognize the name, and the title sounded interesting, so I looked up the paper version of the patent. The quire had never been cut open, but the bookbinder of the library helped me out, adding a free lecture about the quality of the paper. It turned out to be the "difference engine" invented by George and Edvard Scheutz. Nits, comte de Barck, was a Swedish adventurer, Nils Barck, who applied for the patent in his own name (well, an impressive variant of it).[2] So I had not found an unknown inventor of a "machine à calculer et à imprimer des tables de mathématiques", but an ordinary case of fraud mistaken identity.
With the rising availability of patent information on the Web, the library opening hours were increasingly limited. The Library of the Netherlands Patent Office can now be visited by appointment only,[3] despite the fact that old patents and old gazettes not yet fully available online. Fortunately, the Nits patent, FR13480, can now be found in the INPI database (search for "Barck")
Metadata
Data about the patent is called "metadata". I will list the main items.
Title
Depending on the country and the time the title can say a lot or very little. Complete titles are often missing in online databases.
Inventor
Apart from the name of the inventor, in paper patents the residence of the inventor is often indicated as well. In English and recent patents even the full address of the inventor or applicant is given. Databases usually do not provide this extra information. Sometimes even more biographical information about the inventor can be deduced, such as the year of death if the patent is handled by an executor. One can also track name changes, such as that of Eli Hyman Goldberg to Hyman Golber[4] around 1919 or John George Bricken to John Beaver[5] around 1931.
Assignee or applicant
The applicant is the person or agency that applied for the patent, the assignee is the person to whom the patent was granted. This may be the inventor, but also a company or another person. Sometimes there are several persons or companies between applicant and "assignee", each passing the patent to another. U.S. patents call that "by mesne assigment." Take care with English patents: the databases often do not contain the true inventor or applicant, but a British patent attorney or agent.[6] The actual applicant will be mentioned in the text.
Application Date
The date the patent was handed in at a patent office. French patents also stated the time of application with a one minute precision.
Publication Date
Application date and publication date usually differ by a couple of years. Publication dates show a pattern. U.S. Patents are published on Tuesdays,[1] French ones around the first and 15th of each month.
Issue Date
The date on which the patent takes effect is the issue date. In the United States, this coincides with the publication date, but in many European countries the issue date is some time before the publication date. In Germany the difference can be more than one year, which I do not understand. What should the inventor do? When he marketed his invention in the meantime, and someone else did the same, the other can not be accused of infringement, because he could not know the patent. When the inventor waits until publication, he looses one year.
There are no Dutch patents issued between 1869 and 1912.[7]
Types of patents, patent numbers
Apart from the "ordinary" patents, called "Utility Patents" in the USA, a few other types of patents exist. In the databases different types can be recognized by different number formats. Different types usually have different search engines.
In international databases, an "ordinary" patent has an patent number comprising of a country code (US, DE, GB, FR, etc), a number and sometimes a letter. The trailing letter mimics the status of the patent document display (application, publication, abandoned). In most searches for old patents that letter is not relevant. An exception is Austria. AT{number} gives an entirely different patent than AT{number}B. Usually the B variant is interesting for mechanical calculator collectors because AT{number}B refers to patents between 1899 and 1994, and the letter-less version is more recent. And another exception is France. If a French patent is an addition to an existing patent, its number will with an E: FR{number}E. The numerical value has nothing to do with the number of the patent it is added to. A third exception is the German Gebrauchsmuster (DRGM). The Gebrauchsmuster in the European patent database end with U: DE{number}U. A graph showing DRGM numbers versus year can be found at www.holzwerken.de
The United States has two special types of patent: the "Reissue" , listed in international databases as USRe{number}, and the "Design" which is listed as USD{number}. Both types have their own numbering. The number of a Reissue has nothing to do with the number of the original patent.
Most countries started once with patent number 1 and continued ever since. We have already seen that Austria restarted around 1994. Until 1916 the UK patent number restarted each year. In the databases English patents of at that time are listed as GB{year}{number}. The year is the year of registration and the number has at least 5 digits, starting with extra zeroes if necessary. In print the number would be GB{number}/{year}.
Japanese patent numbers started anew for each era: Meiji: year 1 = 1868, Taisho: year 1 = 1912, Showa: year 1 = 1926, Heisei: year 1 = 1989. Japanese patents are numbered in the database as JP{era-letter}{year}{number}B . Patent JP S47-23487B (for a planimeter) dates from the 47th year of Showa, so from 1972.
The numbers of patent applications usually start anew each year. In Germany, complex application codes were used, which often appear in the databases with additional prefixes. So far I have had little success searching old German patents by their application codes.
Classification
For the assessment of the novelty of a patent application one needs to quickly and easily compare it with existing patents. A good patent classification is essential for this task. Historically, there have been several national patent classifications. In 1971 an International Patent Classification was made, which has gone through several versions since then. The national patent databases went to great lengths mapping old classes to the new IPC. The IPC version that is currently used most commonly dates from 2006[8] but the "core" IPC significantly adapts every three years to the latest technological developments. Fortunately collectors of mechanical calculators do not suffer from the latest technological developments.
The IPC consists of 8 sections.[8] At first glance, Section F "Mechanical engineering, lighting, heating, weapons, blasting engines or pumps" seems fitting for mechanical calculators, but it is not. Section F is mainly about energy conversion, which is not the aim of calculators. For collectors of calculating devices Section G "Physics" is interesting, especially Subsection G01 "Measuring, testing" (e.g. G01B5/26 for planimeter) and G06 "Computing, Calculating, counting (e.g. G06G1/06 for straight slide rules)
The U.S. Patent Classification is also still in use. For collectors of calculating devices the main class is 235 "Registers", which strangely enough also covers slide rules (235/70R). The mapping of the U.S. to IPC8 classification is publicly available.
For U.S. Design Patents a separate classification is used. The main classes for collectors of calculating devices are D10 "Measuring, Testing or Signaling Instruments," D18 "Printing and Office Machinery" and D19 "Office Supplies, Artists 'and Teachers' Materials".
The Canadian Patent Classification CPC is very similar to the U.S. Patent Classification. Until 1978, only the CPC codes appeared on Canadian patents. Then, the IPC was gradually introduced.[9]
In Germany, Austria and surrounding areas a "Klass"-system was used. For collectors of calculating devices Klass 42m is the most important.
ECLA is a detailed version of the IPC which is used primarily by patent evaluators.[10]
Family
A patent family is a collection of patents for the same invention by the same inventors with equal priority but applied in different countries. Patents in a family are similar, but can vary in style and level of detail. Databases sometimes contain the full text of only one patent of a family.
References
A patent can contain two types of references to old patents: references by the inventor or applicant (often to its own patents ...) and references added by the patent examiner. In addition, references to technical literature can be made. U.S. Design Patents, which are only about appearances, often refer to sales catalogs. Weird associations have been made. For example, U.S. Design Patent USD148458 for a keyboard,[11] refers to US2170153, a patent for a waffle iron.[12]
Online Resources
When searching online for patents a single source is not sufficient. So I'll list some sources that complement each other.
A good starting point for patents on calculating instruments is the Recherlexikon Patent Database. This database is partially assembled by hand and partly by automatic import from esp@cenet by selected patent classes. The database therefore reflects the preferences of the editors. The main advantage of the Rechnerlexikon patent database is that the metadata that is missing in the official databases is added and normalized by hand. The name of an inventor, for example, is written in a uniform format, making it easy to find more patents of the inventor. There are references to articles on the inventor or the machine. The full-text of many patents is available to the Rechnerlexikon search engine but can not be read by the visitor. In the end, the reader is referred to esp@cenet or USPTO. For German patents the issue date is usually given instead of the publication date. There is no distinction between inventor and applicant/assignee. Instead, persons and companies are listed separately.
Esp@cenet by the European Patent Office contains most European patents, and patents from around the world. The quality of the metadata depends strongly on the age of the patent and country of publication. Full-text is missing for old or very large patents and can not be searched. Most patents are presented as PDFs. If the PDF is missing you can go to one of the national databases are listed below. Data coverage is given in an extensive report, or an up-to-date summary, but it is hard to find the coverage per patent type.
Depatisnet also has worldwide coverage, with a focus on European patents. The search interface is less user friendly than esp@cenet, but the database appears to contain more PDFs of old patents (at least in the areas I'm searching in). The Expert search interface allows creative solutions to the problem of missing metadata. If, for example, a search for French patents with a certain classification (e.g. IPC G06G1/00) published in a given year (e.g. 1901) remains unsuccessful, the year of publication might be missing in the metadata. In Expert mode you can then look for French patents with the appropriate classification whose metadata contain no publication year at all:
AC=FR AND IC='G06G1-00' NOT PY> 1700
You get a lot of "hits" from many years without an indication of the year, but because the French number their patents continuously you can quickly zoom in to patents in a given year. Be careful with the "NOT" operator: it may result in huge datasets that can grind the database to a halt.
USPTO's PatFT contains all U.S. patents (Utility, Design and Reissue). The search interface for old patents is limited to patent number and classification. A separate TIFF viewer or plugin is required to view the old patents. To search old patents by title you could try the "Subject-matter Index of Patents for Inventions Issued by the United States Patent Office from 1790 to 1873,[13] but the next search engine is much more convenient:
Google Patents contains U.S. Patents (Utility, Design and Reissue) and is much easier than the official USPTO database. Unfortunately the Google patent data are quite inaccurate. Sometimes the date is missing and for old patents (before 1976) it does not search on classification. Title, inventor, and assignee may be completely wrong. A sad example is the first U.S. Patent: Google gives an incomplete title, no inventor and a date that is almost a century off. Google Patents does contain full text. The full text of old patents has its flaws, but this is offset by the redundancies in the text. Google offers a download of bulk data in cooperation with the USPTO.
Canadian patents can be found on the website of the Canadian Intellectual Property Office The database contains PDFs of the illustrations, description and claims, but not of the cover page. This means that metadata that is missing from the database, and that is usually printed on the cover page, can not be searched online.
Some title-date-inventor information on German patents between 1841 and 1877 can be found in the archives of the Patentkomission der Zentralstelle für Gewerbe und Handel.
19th century French patents can be found in a special database provided by the French Institut National de la Propriété Industrielle.
Handwritten indices of 19th century patents issued in Belgium can be seen at the State Archives in Belgium. See for example the reference to the Belgian Nits patent (you need a free account to read the scans)
Early Spanish patents and trade marks are in the online historical archive of the Oficina Española de Patentes y Marcas, and later patents in its current archive.
Early Soviet Russian patents can be found in PatentScope (as well as patents from many other countries)
The Norwegian Patentstyret offers an official database of Norwegian patents issued since approximately 1976.
The Swedish Patent och Registreringsverket has an official database of Swedish patents, in which the metadata for old patents is very limited, but PDFs for virtually all patents are available.
Czech (for calculator historians: Czechoslovak or even Austro-Hungarian) patents can be found in the National Database of the Czech Industrial Property Office. The Czech database contains some Hungarian patents. For instance: if CS2718 is requested, the document HU74223 is actually shown.[14] The Czech patent number has been written by hand on the Hungarian patent. There is also a Czech Industrial Design Database, with designs from 1967 and later.
Polish patents, issued after 1923, can be found in the Polish Patent Office Publication Server.
Australian patents, from 1904 onwards, are available in the AusPat database.
Patents from India, starting with no.1 in 1912, can be found in InPASS
For me it was quite an adventure to consult the Japanese database. I failed to find much there, but some planimeter patents emerged, of which I knew the number. Often the patent image is missing. Mind the Japanese eras when searching. Because old patents are only present as images, I use an online Japanese OCR service in combination with Google Translate to get some extra information
Slightly less challenging is the Korean Patents database, with patents since 1945, which has an extensive search engine. The Korean metadata can be directly fed into Google Translate, but you will need a TIFF viewer, like alternatiff, to see the complete documents.
A special collection of patents comes from the APC (Alien Property Custodian). These are patents (or patent applications) by European or Japanese inventors that have been "seized" during the second World War by the US Alien Property Custodian to be licensed to US manufacturers.Applications that became patents can be be recognized in the usual US patent databases by the phrase "vested in the Alien Property Custodian" or the assignment to the "Attorney General of the United States".
Gazettes in which patents are announced or summarized are partly available through Google Books, for example the French Bulletin des Lois. The London Gazette and the Australian Victoria Government Gazette contain summary patent information that is searchable. In some issues of the Amtsblatt zur Wiener Zeitung Austrian "Privilegien" (patents) are listed, but unfortunately this source is only accessible by browsing. Therefore I'm composing a list of Amtsblatt issues with patent information. Old U.S. Patent Gazettes and Annual Reports of the Commissioner of Patents are available online. 19th Century volumes of Scientific American contain patent listings as well.
If you still can't find what you're looking for, check WIPO's list of Patent Databases in Different Countries
Epilogue
The search for old patents can be frustrating: you know for example that a patent, or at least its application, should exist, because another patent refers to its application, but you can't find it because its metadata is missing in the databases. And once you found the patent, it might not help you in answering your question. A good example is Otto van Poelje's "Mystery D&P Slide Rule with Broken Powers"[15] The patent number "DRP 126499" on that slide rule refers to a general patent[16] on the construction of the slide rule, and says nothing about the mysterious scales.
Still, a lot of interesting information can be found in patents. Often you will be surprised by the ingenuity of the inventors, and sometimes by their naivety.
Notes
This is not true for American pre-1848 patents: U.S. Patent 1 was published on Wednesday, July 13, 1836.
Michael Lindgren, "Glory and Failure", Linköping Studies in Arts and Science, 1987.
H.E. Goldberg, "Algebraic total calculating machine", U.S. Patent 1296073, March 4, 1919.
J. Bricken, "Calculating machine", U.S. Patent 1883760, October 18, 1932.
Patent lawyers or agents that are erroneously considered as inventor in esp@cenet include: John Corry Fell, Wallace Fairweather, John William Mackenzie, Henry Conrad Heather Mills Claude Kennedy, Herbert Sefton-Jones, William Phillips Thompson, Alfred Julius Boult, Alfred John Henry Haddan, Justice Philip Middleton, Harold Wade, Harold Williamson Lake, Lake Henry Harris, Charles Aubrey Day.
IPC Version 8 (2006.01) http://www.wipo.int/classifications/ipc/en/ITsupport/versions.html, choose Version 8.
"Patent Classification System: Canadian Patent Classification", CIPO.
European Patent Office, "Coverage of IPC and ECLA classifications". sadly removed
H.L. Clary et al., "Design for a keyboard for calculating machines or similar articles", U.S. Design Patent 148,458, January 27, 1948.
J.T. Misiak et al., "Waffle Iron", U.S. Patent 2170153, August 22, 1939.
Subject-matter Index of Patents for Inventions Issued by the United States Patent Office from 1790 to 1873, inclusive Volume 1, Volume 2, Volume 3
Grimme, Natalis & Co., "Billentyüs számológep közös tengely körül kilengethetö emelökkel", Hungarian Patent 74,223, June 17, 1919.
O. van Poelje, "Mystery Slide Rule with Broken Powers by D & P" in O. van Poelje O. (ed.), "Proceedings IM2010", Leiden, 2010, p.189-190. The mystery was solved by an old manual, see MIR 54.
Dennert & Pape, "Schiebermaßstab", DRP 126,499, December 16, 1901.