Can an innovative novel patent searching app strengthen your inter partes review (IPR) petitions?

Demand for inter parte reviews IPRs has been three times higher than the USPTO expected, with 3,277 IPR reviews filed in the last 3 years. This was according to a recent blog published by the director of the USPTO. The director also pointed that to dated only 12 % of claims available to be challenged in the contested patents (4,496 out of 38,462) have been invalidated in a written decision. Other claims were either not challenged, cancelled, resolved by settlement or upheld. This perhaps contrasts with the view of the PTAB as a ‘patent death squad’ as pushed by some.

The 12% ‘success rate’ suggests that the IPR process is far from a walkover. The IPR process allows the petitioner to submit either new or known prior art. Known (or previously cited) prior art is easy to find, but in some cases this can involve reviewing a long lists of prior art citations.

Similarly it can be tempting to look at the published final or non-final rejection reports for the patent to see which prior art was used as the basis of 102 (novelty) or 103 (obviousness) rejection. While this is always going to be an important step, it is entirely possible that the examiner has missed or ignored other cited patents that are also relevant, particularly if combined with other art in an 103 objection,

Alternatively the position of the petitioner can be strengthened by finding new prior art needs to be found, but this can be costly and require time and delays to find.

But what we could both, and in a matter of seconds and using a web application as easy to use as Google patent:


  • Quickly rank what can be a long list of known prior art in a manner that puts both a fresh and objective ranking of the known prior art ?
  • Find not previously cited prior art at the same time?

Would this be a new, disruptive and cost effective process for strengthening the filing IPR petitions?

The pursuit of this objective had led Ambercite to develop the process of Cluster Searching achieve both of these objectives, using a web application as easy to use as Google searching. We will demonstrate this using two case studies recent IPRs.


First case study – US7597502, Jet Blast Resistant Vehicle Arresting Blocks, Beds and Methods

US7597502 is a patent filed by Engineered Arresting Systems Corporation. This patent has a priority date of September 2001, and claims a foam unit for slowing down out of control vehicles, which include a deformable ceramic foam and a frangible cover on top of the foam. Materials referred to in the specification as frangible covers include the likes of cement board.

This patent has attracted a couple of IPRs from a company called Runway Safe.

The patent itself has 24 listed prior art citations. Of course a diligent reviewer would look at every one of these known citations, but it could be helpful to know which of these 24 known prior art citations is most likely to be similar – particularly in cases where there are a lot more than 24 prior art citations.

A search query in Cluster Searching can be as simple as entering US7597502 into Cluster Searching, and setting to date filter to only show patents filed before the patent’s priority date of September 2001. This query looks like this.


And the result? The three most similar patents in ranked order are:

  • US5193764, Aircraft arresting system, filed in 1991. This disclosed the use of a phenolic foam, but without a cover
  • US3066896  Method and means for decelerating aircraft on runways, filed in 1959. This includes a disclosure for a flexible, compressible material with a flexible cover.
  • US5902068, Vehicle arresting unit fabrication methods, filed in Feb 1997. This discloses a concrete foam, which can include a hard coat layer of a thin layer of cellular concrete having a higher dry density.

So how does compare with the examiner found? In this case, the examiner cited US4007917 as being the basis for a 103 objection. This disclosed a ceramic foam covered with a plastic film. This is also relevant, but shows the first benefit of cluster searching – a different ranking is produced (and in an objective manner), which may produce new insights on the known prior art.

And what about unknown (not previously cited) prior art? Near the top of our list of unknown prior art is:

  • US3967704 Vehicle decelerating means, filed in 1971. This discloses a bed of crushable rigid foamed material, which can include a protective covering such as paints, lacquers, bitumen and waxes.
  • GB1122297, Improvements in arrester pads for aircraft runways, filed in 1968. This discloses an arrester pad made from Improvements in arrester pads for aircraft runway, made from honeycomb construction ,..of foam material, synthetic plastics or aerated concrete, along with an upper skin,

So as you can see, Cluster Searching was able to list a series of patents that are very similar to the patent being contested, at least as similar as what is previously known.

You can also see in one of these unknown citaiton documents in a non-US document. You may be surprised how often examiners appear to avoid citing prior art outside of their own jurisdiction. In contrast Cluster Searching can be excellent at finding and ranking highly relevant prior art from other jurisdictions. This is an important benefit. 


Second case study – US6291966, Method and an apparatus for storing and communicating battery information

US6291966 was filed by Ericsson with a priority date of January 1998, and claims a battery with a separate system to log battery information, suitable for use in a mobile phone.

This patent has attracted an IPR from Apple.

The patent itself has just two listed known citations – and yet Cluster Searching was able to return many ‘unknown’ citations in a simple search



Heading the list of unknown (rior art patents returned by this query are

  • US5939856, Battery and charging system using switchable coding devices, which also discloses a battery information circuit, and was filed by Motorola in May 1997.
  • US5606242, Smart battery algorithm for reporting battery parameters to an external device. This was filed by Duracell in October 1994.
  • US6104967, Fault-tolerant battery system employing intra-battery network architecture. This was filed by 3M in July 1997.

And there are many others in this list along a similar vein.

Compared to the just two known prior art patents, this list of unknown and yet potentially relevant prior art patents could help strengthen IPR petitions for this case.


Benefits of Cluster Searching

These two case studies start to illustrate the benefits of cluster searching.

  • An objective perspective is used to rank the known prior art in a new way, so providing new insight on existing information.
  • A list of unknown prior art is also produced. In some cases this can include patents from other jurisdicitons that can also be highly relevant. 

Together, this can greatly expand the patent list for an attorney to base an IPR on. Best of all, this list can be produced in seconds from any computer, and without having to instruct others and wait for the results. Even if other search processes such as outsourcing are used, Cluster Searching can be used to augment relevant patents found by other searchers or processes.


Want to try Cluster Searching for yourself?

Cluster Searching is a very fast and easy to use web application. Free demonstrations and confidential trials are available to qualified applicants – please contact us to arrange a short demonstration and trial. You may be surprised (and impressed) by just how much time and money you may save.

Matter pricing is available to patent litigators. 


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