When testing your invention can invalidate your patent

Article  \  31 Mar 2022

Between September and November 2011 at a small cul-de-sac in Jupiter, Florida Mr. Berardi was experimenting with expandable garden hoses. Mr. Berardi recorded videos of the construction and testing of the expandable garden hoses as a record to demonstrate his practice of the invention. As the hoses got longer, up to 50 feet, Mr. Berardi had to move outside. He worked near his outside tap, to the right of his house looking out towards the front lawn and road. A United States patent application was filed on 4 November 2011 and a corresponding UK patent application followed in 2012.

In August 2002 Mr. Claydon, working for the company Claydon Yield-o-Meter, connected a prototype seed drill to a tractor and went for a test run on a farm in Wickhambrook, Suffolk. Working with his brother and an assistant he spent ten hours ploughing a field confirming that the prototype seed drill could successfully use aligned tines to disturb soil in spaced apart rows. A United Kingdom patent application was filed on the 29 March 2003.

In each case a UK patent would be granted. However, the granted patent would later be challenged based on the prior uses described above being public disclosures. The opponents claimed that because of the use of the inventions before filing a patent application in places where the public could see the invention the inventions lacked novelty.

In the case of Mr. Berardi1 it was argued that a skilled person standing on the public road at the front of Mr. Berardi’s house would have observed all the construction and testing of his hose. The Judge accepted that this could have occurred and would have invalidated the patent. However, he was convinced that if Mr. Berardi had seen an observer, he would have packed everything away before the observer could identify the inventive features of the expandable hose. This meant the patent survived the prior use attack, although it was held invalid on different grounds.

In the case of Mr. Claydon2 it was discovered that an unmarked and unmaintained public footpath skirted the field around which he was testing the seed drill. Although a 6ft hedge separated the footpath from the field there were three gaps from which the field could be viewed. It was accepted that no-one was present to see the testing through the gaps. The Judge found that a skilled person standing on the footpath would have been able to see the prototype and the drilled soil and determine the inventive features of the prototype. Considering the size and operational constraints of the tractor and seed drill the Judge decided that Mr. Clayton would be unable to take action to prevent observation when he became aware of an observer. The Judge ruled that because it was possible for a disclosure to have taken place to the public the prototype was made available to the public, and the patent claims were invalid for lack of novelty.

Prior disclosure including prior use can invalidate a patent for your invention. It is important to consider whether any public access is possible to experiment or testing of your invention. In New Zealand and Australia, the patent legislation provides grace periods which may provide a defence to public prior use claims in the 12 months before applying for a patent. However, grace periods have limited scope and best practice is to file an application before any possible public disclosure of an invention, either through prior use, oral or written description, or any other way. This is particularly important where corresponding patent applications may be filed in other jurisdictions, such as the UK, where strict prior use rules apply.


[1] https://www.bailii.org/ew/cases/EWHC/Patents/2019/991.html

[2] https://www.bailii.org/ew/cases/EWHC/IPEC/2021/1007.html


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