Patent Searches and How to Find Similar Inventions.

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The following is a transcript of Episode 4 from the "Patenting for Inventors" Podcast.

This episode is going to be about how to conduct a patent search to determine whether or not there are similar inventions that will prevent you from getting your own patent. I have to give a huge disclaimer first. There is an entire industry related to patent searching. There are people whose entire career is patent searching. Even a lot of patent attorneys don’t do complicated patent searches on their own, but hire specialized patent search firms.

Why do you want to do a patent search? The main reason is cost. There’s actually no legal requirement for you to do a patent search before you file a patent application, but the whole process of patenting your invention can be tens of thousands of dollars. If you’re interested in getting patents across the world, it could be in the hundreds of thousands of dollars. If you could just spend a little bit of time and energy or a few thousand dollars to hire someone to do a search for you, then you can cut your losses early if you find out that your invention already exists, or something really close to it exists.

In the last episode I talked a little bit about prior art, which is a term used in patent law for anything publicly known before you made your invention. A patent search is just one part of a prior art search because patents are just one kind of prior art. Prior art can also be catalogs or websites, or anything that was known at the time of the invention, not just patents and patent applications. To start your prior art search, you might just want to go to Google and start trying to find out if your invention has been done. In my example from the last episode, where I talked about a pencil with three erasers, just type in pencil with three erasers. Nothing popped up that I saw that was a pencil having three erasers, but you don’t just want to stop at a general Google search because there’s a good chance that you’ll miss a lot of stuff. In this episode I’m only going to be going through searching patent databases, because in whatever field you’re in, you probably know the other places to search. If you’re in the toy business, you probably know how to search toy catalogs. If you’re in the tool business, and you have a new tool, you probably already know how to search tool catalogs. I’m just going to be going through the patent database searches.

There are three websites that I like that offer free patent searching. One is the United States Patent and Trademark Office. The website is Another is Google patent search at and the last one that I use a lot is called at None of these are perfect, and I find the United States patent and Trademark Office website not to be that user friendly, and it only searches patents and patent application from the United States. So for free databases that can search worldwide patents, I use Google patent search and pretty regularly. (Patentscope through WIPO is also very useful for worldwide patents).

If you combine the Google patent search and patent search, you’re going to get patent results in China, Europe, the U.S., Germany and a few other countries in your patent search. Most people who have filed a patent application somewhere will probably apply in one of these countries so you cover most of your bases if you use them. Now it’s always possible that someone filed their patent application only in Egypt and nowhere else, and you won’t pull that up, so a patent search is never going to be 100% perfect at finding everything that might be relevant, but it might be good enough so you can make an education decision on whether to go forward with your patent application.

How do you do a patent search? We’re going to do a simple example search that everyone can follow. One of my favorite kitchen gadgets is 3 in 1 avocado splitter, pitter, and slicer. There are lots of them, but the one I have is the Oxo good grips 3-in-1 slicer and you can get it on Amazon for $10. I don’t get a commission and I’m not a paid sponsor, I just love this thing. You should check it out on Amazon so you can see the features I’m talking about when I’m explaining the search. We’re going to pretend that I’m original inventor of this device so it’s not already being sold on amazon and I’m going to do a prior art search to see if maybe I could get a patent on it.

There are lots of ways to do patents search, but I’m just going to start with a really simple and basic way, which is just typing in a couple words about the invention into the Google patent search bar.

I typed in avocado slicer. In my search it came up with 234 results. Now when you get these results, you sort by date, selected only issued patents, pick which patent office you want to see the results from and other things.

On the left side you can see one image from each of the patents so you can get a rough idea of what the avocado slicer looks like in that patent. I’m scrolling down and don’t really see anything exactly the same as my concept, which has a splitting single blade at one end, a pitter in the middle and a slicer that has a bunch of blades inside of a loop. That’s just the first page, then at the bottom I click to go to page two of the search results, and I actually see a patent called “Avocado pitting device” and that is the exact device that I see on Amazon. I can see that that they got a patent for this and the patent application was was filed August 23, 2011. I’m going to pretend with this patent search example that it’s August 23, 2011 and not really take into consideration anything that came afterwards because those things aren’t relevant to whether my invention was new or obvious, because they didn’t exist.

Let’s say you don’t want to go through a read 234 patents. You can start adding additional words in your search bar to narrow it. I put in “avocado slicer pitter” instead of just avocado slicer, so only patents that have those three words show up, and if you do that, there are 71 results. Now sometimes these words may show up in a patent and have nothing to do with the invention. There could just be avocado slicers that do not have a pitter, that just describe avocados, and it may happen to mention that if you want to take the pit out, you need to buy a separate pitter device. You really have to click on the link to read the patent, and look at the drawings to see how close your invention is to the one that was described the search results. The first step is to try to find the patent application that is most similar to your patent. This can take a while to do. I read through a bunch of these already and one that has a lot of the same features is the first one that popped up in the search, which is called “avocado pitter/slicer.” It’s patent number 7,421,786 and you can see it has a handle, blades, and a loop. I don’t see a slicing blade, and the thing that takes the pit out doesn’t have blades that poke into the pit to pull it out. The pitter in this device is just a smaller loop that is able to scoop out the pit instead of jabbing it.

There’s another patent that has slicing blades to split the avocado and the inventor is Narlock, patent 5,115,565, but it doesn’t have the same kind of pitter. I looked through these and nothing really struck me as really being that close to the Oxo splitter, pitter, and slicer. Considering that this invention got patented, the inventors were able to convince the examiner that this was new and nonobvious.

Now you have to be careful about your patent search. You can’t just assume that that your invention doesn’t exist because you put in the search bar what your invention is. Maybe your invention doesn’t exist for avocados but something extreme similar worked with removing peach pits, or there was a separate device that was able to take the pit out of the an avocado but it wasn’t combined with the splitter and slicer. The examiner might take that totally separate pitting device and say it would have been obvious to combine that pitting device into a splitter and slicer to make a 3-in-1 device instead of a just a 2-in-1 device. There are just all kinds of things you have to be careful of when you do your search.

What I just described was a very simple key word search and there are all sorts of ways to do specific kinds of key word searches that narrow or broaden the results. There are just too many ways to describe how to do keyword searches in an introduction to patent searching. There’s another way to do a search called a classification search which can be used to narrow down relevant patents.

The Patent Office gives every invention a classification number. You can find the classification manual by searching on the internet for the manual of U.S. patent classifications.

In our example, there’s a classification for “food and beverage apparatus” which is class 99, which is a really broad classification. So the patent offices gives devices subclassifications. And there’s a sub-classification for food and beverage apparatus that separate one internal portion from another, which is what our device does, and this is class 99, subclass 538. But you also have to be careful about figuring out what class your device is in because it could be listed in class 99 for food and beverage apparatus but there’s also class 30 which is the classification for cutlery. The patent classifier might put this avocado in class 30 so you probably want to search multiple classes that your invention could fit into. You can get a list of all patents in a certain class and subclass, and then you can use a keyword search to narrow it down even more.

Sometimes you can get so detailed in your search you start excluding things that are still relevant because maybe you used the word slicer, but the patent application uses the word “cutter” instead of slicer, and you might miss that patent. But if you’re too broad then you’re going to have thousands of patents to sift through, which is just too difficult to do. So there’s really an art and science to patent searching.

The last thing I’m going to suggest you do is what is called backwards and forward searching the relevant patents. When you do a Google patent search and click on one of the patents, scroll to the bottom of that patent and you’ll see a heading called “Patent Citations” and these are references that the inventor thought were similar enough to his or her invention that the inventor legally had to disclose it to the Patent Office. Since the inventor thought that these patents were similar to his patent, the same patents might also be similar to your invention, so it’s worth taking a look at those citations. This is called a backward citationn search.

Then after you do that, take a look again at the bottom of the patent and you’ll see a heading that says “Referenced By” and these are patent applications that came AFTER the patent you’re looking at. These later applications referenced this patent because the inventor thought that this patent was relevant to their own invention. You should take a look at these too because these will be more recent patents that could be related to your invention. This type of search is called a forward citation search.

To sum up, the three ways that I like to do my patent searches are keyword searches, classification searches, and forward and backward citation searches. I barely scratched the surface of how to do a proper patent search, but at least it’s a starting point on how you can do a very basic one, and if you find something nearly identical to your invention, you can cut your losses and not go forward with your application. If you’d like a professional patent search and patentability opinion, I do offer those services through Diament Patent Law.

One thing that is very important is that the type of patent search I described is to determine the likelihood that you will receive a patent on your invention. This type of search is NOT for figuring out whether you are infringing someone else’s patent, where you’d have to do a non-infringement search and a freedom to operate opinion. You can actually get a patent on your new device but at the same time be infringing someone else’s patent, and get sued, even though you have patent! I’ll go over non-infringement searches in a later episode after I talk about the claims of an invention.