Updated November 5, 2020:

Old Patents

When old patents expire, they typically become open for the public to use. Generally, the expiration date on a patent is twenty years from the filing date. Thus, any patent that is older than 20 years is available to the public to use for free without violating a patent right.

An abandoned patent is one that an inventor simply gives up during the patent process or fails to continue paying any associated fees.

How to Search for Old or Abandoned Patents

If you are interested in finding patents that are either old or abandoned, there are a few things you should do:

  • Conduct a patent search relevant to your invention or product. Free search engines include Google Patents Advanced Search, which allows you to search for patents that are more than twenty years old. If you find a patent you are looking for, make sure to write down the patent number and any other relevant information.
  • Alternatively, you can search the U.S. Patent and Trademark Office (USPTO) Public Pair website. On this page, you can either search by a specific patent number or, if it’s a patent application, by publication number.
  • Browse the patent status section to see if a certain patent is listed as “patented.” This means that it is currently active and not available for free public use. However, if it is listed as “expired” or “abandoned,” then it is free to use without violating any patent rights.

Old and abandoned patents are a great way for an inventor to reference previous research and designs to try and make improvements upon them. This type of model incentivizes creativity and innovation and has led to many subsequent patents that further the economy. It is important to note that even if a patent is abandoned or expired, you should always consult a patent attorney to be sure that the original owner did not file a related patent that would preclude you from using the old or abandoned patent.

How to Obtain Old Patent Drawings

If you are interested in obtaining old patent drawings that are not available on the internet, a word of caution as you begin your search. There has recently been a worrisome trend in which antique dealers have been trying to sell old patent drawings at an unreasonable price, claiming that they are very rare pieces of history and hoping an unsuspecting buyer will take him or her at their word. Be aware of this, as most of the time it is merely a scam. If you can find an old patent drawing, it will typically be free.

Before you begin your search for old patent drawings, there are three questions you should ask yourself:

  • Do you have the actual patent number?
  • Was the patent filing date before 1971?
  • Do you have any idea about when the patented product was made?

If you know the specific patent number, it is very easy to find what you are looking for. There are many websites now that offer this type of information freely. Often, older products will have the actual patent number inscribed somewhere on them. This was mainly due to the intense competition and fierce desire to guard one’s own patent.

An unconventional place to search is on eBay. Typically, eBay will display a magnified version of the product to easily show the inscribed patent. This helps potential buyers know that what they are buying is authentic and can be a good place to search for old patents.

How to Find Old Patents with a Specific Patent Number

If you have the actual patent number of a product you are looking for, you can search the U.S. Patent and Trademark Office’s website at http://www.uspto.gov/patft/index.html.  From that page, you can click on the box under “query” and type in the patent number. For example, type in 1,869,447 or 1869447 and both will give you the same result. Once you find the patent document, you can save the patent drawing as a “.TIFF” file that allows you to print the image.

If you need help with searching for an old or abandoned patent, you can post your legal need on UpCounsel’s marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law, and average 14 years of legal experience, including work with, or on behalf of companies like Google, Menlo Ventures, and Airbnb.