Patenting for Inventors Ep. 173: How to Trace a Patent's Relatives—and Why It Matters

Patent families often confuse inventors and entrepreneurs. In this episode, Adam Diament breaks down how patent applications branch into related filings—continuations, divisionals, and continuation-in-parts—and why tracking them matters for your business.

You'll discover how to use the USPTO Patent Center to spot the "continuity tab" that reveals all related applications, and how international tools like Google Patents and Espacenet expose INPADOC family members across borders. Adam walks through real scenarios: designing around a competitor's patent, preparing for litigation, and building a robust portfolio with multiple branches protecting hardware, software, and methods of use.

Whether you're researching a competitor or planning your own patent strategy, understanding patent families is essential business intelligence. Learn when to file a continuation before your patent issues—and why missing that deadline can cost you future protection. Contact Adam Diament at Nolan Heimann to discuss your patent family strategy, or explore the patent law practice for more resources on building and defending your IP portfolio.

Patenting for Inventors Ep. 173:

Podcast Transcript:

Hello, and welcome to the Patenting for Inventors podcast. I’m your host, Adam Diament, a registered patent attorney and partner at the law firm of Nolan Heimann in Los Angeles, California. This episode is How to Trace a Patent’s Relatives—and Why It Matters  

Okay, so you know how when you meet someone at a family gathering and they’re like, “I’m your second cousin once removed,” and you just kind of smile and nod and hope no one asks you to explain what that actually means? Well, welcome to the world of patent family trees. It’s a little like that, but with fewer awkward hugs and more international paperwork. 

So here’s the deal. A patent family isn’t a family in the emotional sense. It’s more like a paper trail of related patent applications that all come from the same original filing. That first filing? Think of it as the grandparent. Then you’ve got children, cousins, stepchildren, adopted kids — all depending on how the applications were filed, continued, divided, or branched out into other countries. 

Now, why should you care? Like, really, why should any inventor or entrepreneur spend time looking at this stuff? Well, let’s say you see a patent number and you’re curious if there’s more to it — maybe the company that filed it has other related patents that could block you from doing something similar. Or maybe they have stuff that’s about to expire. Or you’re worried they’ve filed something in Europe or China that might affect your market over there. That’s when this becomes really important. 

The easiest way to start snooping around is to go to the USPTO’s Patent Center — and plug in the application or patent number. If it’s a published application or an issued patent, you can usually find what’s called a “continuity tab.” That’s the section that shows you what came before and what came after. Like, if this application was a continuation, or a divisional, or if it has kids that were spun off. 

So let’s say you filed a non-provisional application. A year later, you file a continuation to add more claims. A few months after that, you file a divisional because the examiner said you had multiple inventions in one application. Now you’ve got this little web of filings that all share the same parent. That’s your patent family. 

Now, you might be thinking, “Okay, I get that. But how do I know what’s part of the family if it’s in other countries?” That’s where tools like Espacenet or Google Patents come in. They let you see “INPADOC” family members. And yeah, I know, INPADOC sounds like a Star Wars droid, but it’s basically a database that shows applications across different countries that are related by priority. So if you filed a U.S. provisional, then a U.S. non-provisional, then a PCT application, and then entered Europe, Japan, and Canada, those are all part of the same INPADOC family. 

And that’s not just trivia. That’s strategy. Because let’s say you’re designing around a competitor’s patent, and you think you found a loophole. But then you dig into their family tree and discover that, oh no, they have a related filing in Canada with broader claims. Or one in China that’s still pending. That changes your calculus real quick. 

Another reason to care is litigation. If someone’s suing you for patent infringement, you want to look at the whole family. There might be something in a sibling application that helps you out. Maybe they made a statement during prosecution of a continuation that contradicts what they’re saying now in court. That’s called prosecution history estoppel. Fancy term, I know. But the point is, tracking the full patent family can give you ammo. 

And if you’re the one building a patent portfolio, you want to think about how your filings are related. Should you file a continuation to go after new infringers? Maybe file a continuation-in-part because you’ve improved the invention? Or maybe a divisional, because the examiner forced you to split it up? Each move adds a new branch to your family tree. And you want to know where every branch is growing. 

Alright, so how do you actually visualize all of this? There are some third-party tools that do a decent job. Some of them even show a literal tree, like with branches and lines connecting parents and children. Google Patents actually has a visual “Family” view now for some patents, which is kind of handy if you don’t want to stare at a spreadsheet. 

But even without fancy tools, just using the USPTO Patent Center, you can start building out a mental map. It’s kind of like looking at a family photo album. One that I use that is free is at interstellarip.com. You might see a sibling application that was abandoned, or one that’s still alive and kicking. That helps you predict what the applicant might be planning next. 

Now, let’s say you’re trying to figure out how all this relates to your own patent. You filed a provisional application a year ago, then filed a non-provisional claiming priority to that provisional. That’s a very basic two-generation family tree. Now imagine six months later you file a continuation because you want to go after a narrower version of your claims — or maybe a broader one that got left out the first time. Boom. New branch. Then maybe the examiner says, “Hey, you’ve got two inventions here,” so you file a divisional. Now you’ve got another sibling application growing on the side. 

It’s like you planted one seed — that first filing — and now you’ve got this weird patent bonsai tree growing in multiple directions. Each new filing adds more complexity. But it’s strategic complexity. Because maybe one application protects the hardware version of your product, and another protects the software, and another covers the method of use. Different branches, same family. 

And one of the reasons companies do this is timing. Let’s say your original patent is about to expire or issue. You can file a continuation before it issues to keep the family alive and go after new claims. But once that original patent issues, the door shuts. You can’t file a continuation afterward. So staying on top of your patent family tree isn’t just about organization — it’s about keeping your options open. 

Now, if you’re looking at a competitor’s portfolio, the same logic applies in reverse. You want to know which filings are still pending. Which ones might turn into something. Which ones have been abandoned. You might find something super broad that looks scary — but then you realize it was rejected and never appealed. Or maybe you see a child application that’s still pending with claims that are uncomfortably close to what you’re doing. That’s the kind of stuff you want to track early, not when you get hit with a cease-and-desist letter. 

Another thing to keep in mind is that not all applications in a family are published at the same time. Some may be delayed. Some countries have different rules about publication. And of course, unpublished U.S. applications generally don’t show up in public databases until 18 months after filing, unless the applicant requests non-publication. So sometimes the family tree has some invisible ghosts hiding out — like a branch you don’t see until it’s already issued. 

Oh, and just a quick sidebar here — sometimes inventors come to me and say, “Wait, I just found another patent that looks almost identical to mine, and it’s owned by the same company. What gives?” And the answer is, it’s probably a continuation or a continuation-in-part. It’s not a duplicate. It’s a sibling. And if the claims are different, even slightly, it can be a different patent with separate rights. 

And hey, if you’re in licensing or fundraising mode, investors and partners love seeing a healthy patent family. It signals you’re serious, you’ve got multiple angles covered, and you’re building a real IP moat. But it also means you need to keep your tree organized. I’ve seen companies where the founder couldn’t tell me which applications were still pending, which were allowed, and which were dead. That’s not a good look. 

If you’re working with a patent attorney — and you really should be — they should be tracking this for you. But if you’re DIY-ing your patent research, then take advantage of those free databases. Google Patents is great for a quick overview. The USPTO Patent Center is great for U.S.-specific data. And if you’re international, Espacenet or Patentscope will let you peek into filings all around the world. 

The bottom line is, patent family trees aren’t just for patent nerds like me. They’re useful business intelligence tools. They help you figure out what protection you have, what’s still possible, and what your competitors might be doing next. You wouldn’t walk into a negotiation or a product launch without knowing who your competitors are — so don’t launch without knowing what’s in your patent family, or theirs. 

And you don’t have to get all spreadsheet-crazy about it. Even just checking in once in a while — like every time you get a patent office communication, or when you’re planning a product update — can help you stay one step ahead. Think of it like checking your credit report. You don’t have to stare at it every day, but you really don’t want to be surprised by it either. 

That’s it for today’s episode, and if you need help filing a patent application, or other intellectual property, give me a call at 424-281-0162. Until next time, I’m Adam Diament, and keep on inventing!