How to quickly find new and relevant keywords and class codes for patent searching

How to use Ambercite to strengthen a conventional patent search

July 10 2019 Here at Ambercite we have long realised the limitations of searching by keywords and class codes. No matter what you may think are the best and most appropriate keywords and class codes for a given technology, and you may be completely right, you can almost guarantee that you will have missed some relevant keywords or class codes.

This came out yesterday in a search for a construction invention. I had searched in this area before, understood the technology, and even had a reference patent to start with, that exactly described the invention, and in clear terminology. I was running a Freedom To Operate search, and wanted to find all active patents of a particular country that that might refer to this concept - the sort of search that needed to be done in a conventional patent database.

But did I have all of the right keywords? Or class codes for that matter?

This was where Ambercite came in. Because this was a conventional keyword and class code patent search, I wanted to be sure that I had all of the right keywords and class codes. So the process I went through was a little like what will be shown below. However the subject area to be discussed will differ from the commercial search.

To demonstrate this, I might instead run a search for similar patents to US20130105355A1, which claimed a Shipping Carton Convertible To Display Configuration, as shown below.

shipping carton.png

There are two key concepts in this invention - a carton and a means of opening this to make it a display carton.

Lets have a look at the 50 most similar patents to this patent, via an Ambercite search. The search looks like this:

And the top three listed results look like this, or click here to see all of the results. In this display, I have highlighted the words carton and display:

top three results.JPG

This is interesting - while all three of the top results refer to ‘display’, only the third listed patent refers to the word ‘carton’. The other patents use the words ‘container’ and ‘shipper’ instead.

Already we are starting to see the variety of language used for even a simple concept. A little further down the list we come across this patent:

Packaging for consumer goods.JPG

Which does not use the word carton or display in the title or abstract - but does include a ‘tear strip’ to convert this ‘box’ into a display carton.

And we can keep going - for example finding a ‘‘retail ready container’.

retail ready container.JPG

All which proves just how variable terminology can be. This variability can come from different applicants, different understandings of the invention, different patent attorneys, or the patents being initially drafted in different countries or in different languages, and then being translated using different translators into English. Sometimes I am convinced that some patent attorneys go out of their way to describe an invention without using the most common used words for the concepts.

There are many reason why terminology is so inconsistent, but ultimately it does not matter - the point is that we need to be prepared for such variation in terminology (which is an excellent reason to use Ambercite to reinforce conventional patent searching).

What about class codes?

US20130105355A1 has just one listed class code, namely:

B65D5/5445 Lines of weakness to facilitate opening of container or dividing it into separate parts by cutting or tearing for dividing a tubular body into separate parts

This is perfectly relevant, but what can we learn from the similar patents we found using Ambercite?

It turns out that the first few patents in the list also listed the above class code, but the 5th ranked patent, US9994344B2 which covered a Shipping container convertible into a dispenser container or a display tray, again perfectly relevant, did not. Instead it listed these class codes:

  • B65B43/10;

  • B65D5/16;

  • B65D5/18;

  • B65D5/321;

  • B65D5/322;

  • B65D5/68;

  • B65D5/72;

  • B65D5/725

I am not going to detail all of the class codes, but they all fall in the right areas, in particular this one:

B65D5/16 Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper by folding or erecting a single blank to form a tubular body with or without subsequent folding operations, or the addition of separate elements, to close the ends of the body the tubular body being formed with an aperture or removable portion arranged to allow removal or insertion of contents through one or more sides

To further reinforce this point, I used a filter in Ambercite to filter out all patents that did not refer to B65D5/5445 . 26 patents remained in the top 50 most similar patents, and almost all disclosed the concept of a carton convertible into a display carton.


We often talk about using Ambercite to extend a conventional patent search, and this is always a great idea. But this in case we used Ambercite for a different purpose, namely to help identify the full range of keywords and class codes that might be apply to a conventional search. This was a great test of my assumptions about what class codes and keywords were relevant, even though I had a directly on-target patent for which I could base my assumptions on.

Want to try Ambercite for yourself?

Simply visit our website, sign up for a trial license, and you to could be using Ambercite to strengthen your patent searching.

Mike Lloyd