You're probably already lacing up your running shoes at the very thought of the mention of the International Patent Classification (IPC), but please stick around; I promise this will be almost painless.

If you're like me, your introduction to the IPC was a seemingly random string of letters and numbers rolling off someone's tongue. It made no sense at the time, and yet, despite the years, when one might think they have it down pat, there are still times when it's a head scratcher.

I'm going to try to help you, firstly, find the right patent classification for your idea, and secondly, help you use that information in a meaningful way, but before all that, a few letters and numbers.

A typical IPC classification looks like A61K31/192. This one happens to relate to pharmaceutical compositions containing ibuprofen, but let's break it down into its constituent parts.

An IPC classification is composed of five parts: section; class; subclass; group; and subgroup, each building on what has come before. In the example above the section is A; the class is A61; the subclass is A61K; the group is A61K31, and the subgroup is A61K31/192.

Sometimes you'll see IPC classifications with a space between the subclass and the group, or with some extra zeros in the group numbers. They all mean the same thing.

There are eight sections, labelled A to H, and these cover broad technology areas as follows:

  1. Human necessities
  2. Performing operations; Transporting
  3. Chemistry; Metallurgy
  4. Textiles; Paper
  5. Fixed constructions
  6. Mechanical engineering; Lighting; Heating; Weapons; Blasting
  7. Physics
  8. Electricity

These sections get subdivided and further subdivided until you end up with these figures for the most recent iteration of the IPC published in January 2020.

Eight sections – 131 classes – 646 subclasses – 7518 groups – 68030 subgroups.

I know those are daunting numbers if you want to find the right classification but the IPC is a hierarchical system that is laid out in a very orderly fashion.

Here's the IPC layout for A61K31/192.

There are a series of dots known as 1-dot subgroups, 2-dot subgroups and so on. All 2-dot subgroups are subsets of 1-dot subgroups, and 3-dot subgroups are subsets of 2-dot subgroups. What we are aiming for is the last possible subgroup into which we could put our idea, or in this case, ibuprofen.

We're looking for pharmaceutical compositions containing an organic compound which brings us to the group A61K31. Ibuprofen is an acid, so A61K31/185 (1-dot). It's also a carboxylic acid, so A61K31/19 (2-dot). It's not an acyclic carboxylic acid so we drop down to the next 3-dot, and it is a carboxylic acid having aromatic groups, so A61K31/192. It doesn't have two carboxyl groups nor does it have an amino group, so we stop at A61K31/192.

Still here?

I can't imagine I've made your views on the IPC more positive so far, but this is where I make it easier.

The bottom line is: Forget about all those dots (if you want).

The easiest way to find the right classification for your idea is to use the knowledge of someone who knows the IPC inside out. Conducting a narrow keyword search for your idea should bring up earlier patent applications in the same technology area. All of these earlier applications will have an IPC classification on their front page, and they are there because a patent examiner or searcher has determined they are relevant to each of those inventions. The subgroups (e.g., A61K31/192) might be different but you will find that they all have the same group (e.g., A61K31), and it's the group you're after.

Now you can look up that IPC group online and see if you can further classify your idea. Then, in AusPat for example, you can conduct a search for an IPC classification (or IPC Mark as it's described there) by looking for A61K31/* as in our example. The /* after the group is necessary for the search to capture all of A61K31 in this database.

Another method of finding the right IPC classification is to use a tool such as the IPC Search tool. For this I'll go back to the battery powered surfboard idea from my previous article on quick patent searches.

A search in the IPC Search tool for "surfboard" brings up two classes which are for two different subgroups in the group B63B32 (water sports boards).

Unfortunately for my example's purposes, WIPO has just created a new class for surfboards or water sports boards in general. In the 2019 edition surfboards were classified within a class for vessels adapted for special purposes, so until the relevant patent applications are reclassified we also have to search the subgroup B63B35/79.

Doing the same thing for "battery" gives 75 or so results, which should be expected for something that occurs in multiple applications including vehicles and circuits, and also has a military definition. We need to check each classification until we find the one most appropriate for our needs. In this case it is H01M. We are at the subclass level now as the different groups cover various types of battery.

In the previous article we focussed solely on keywords to reduce the number of patent applications to consider in a search for a battery powered surfboard. The keyword search gave us about 300 hits in the search results.

It would be possible to combine the classifications we have found in a search that looks for patent applications in both the surfboard and battery classes. It's not something I do a lot of, and is mainly for trying to pick out a combination of features that has been described in an unusual way or misclassified within the class of interest, such as describing a surfboard as a water sports board.

If we do that search we get about 30 hits in the search results. It's not too many, and useful to consider them even if they would also appear in the next couple of searches as well.

The following searches are essentially backups to the earlier keyword search, where we will swap one of the keywords (or set of keywords) for the equivalent IPC classification. I previously identified the following variations on describing a surfboard: a surfing board, a watercraft board, a water sports board, a surfing device, and a surf board. There could be others, but chances are most of them have been classified in B63B32 or B63B35/79.

The search then is, (IPC = B63B32 OR B63B35/79) AND (keyword = battery OR batteries OR ...). You would also need to find a set of keywords that describe a battery. Doing this search gives about 350 hits, which is consistent with the keyword only search.

Searching the other way round, i.e., (IPC = H01M) AND (keyword = surfboard OR surf board OR ...) gives about 50 hits.

Putting all these four searches together gives about 400 hits because there is a lot of overlap between them, but you are getting more than a keyword search alone, so the IPC can be invaluable even at a very high level to provide additional patent applications you would otherwise have been unaware of.

So, take a deep breath and dive into the IPC as far down as you dare. Even just having a paddle can make your searching much more effective.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.