(1) Blue Gentian LLC (2) E. Mishan & Sons, Inc. trading as Emson v (1) Tristar Products (UK) Limited (2) Tristar Products Inc.
This was a decision from the Court of Appeal following an earlier decision from Birss J at the High Court.
The decision looked at whether the judge at first instance had erred in his construction of the prior art references.
The patent related to an expandable garden water hose having an elastic inner tube and flexible non-elastic outer tube. The two tubes were connected together only at the ends. At first instance, Tristar did not contest that their actions infringed the patent, but argued that the patent lacked novelty and inventive step in view of two published United States patent applications, McDonald and Ragner. However, at first instance, Birss J found the patent to be valid over these two documents.
Tristar appealed only on the grounds that the judge had erred when assessing obviousness.
In relation to Ragner, Tristar argued that the judge had wrongly construed the document and that his errors of construction led him to conclude, wrongly, that their obviousness attack should be rejected as reliant upon hindsight. However, Tristar’s arguments were rejected by the court:
I think important to have in mind that the claimed garden water hose assembly of the patent is an improvement on known garden hoses in that it is light in weight and contractible and therefore easier to store, and kink resistant. These are significant and real advantages. In such a case it seems to me that it is particularly important to avoid hindsight in considering an allegation of obviousness because it is all too easy to say, after the event, that the invention was obvious and could have been arrived at by a series of apparently easy steps.
An essential feature of the device of the patent is that the inner tube and the outer tube are only connected at their ends. The structure depicted in figure 3A of Ragner is very different indeed. I think the judge was therefore entitled to conclude as he did that it was not obvious to have the two covers sliding freely relative to each other in an embodiment in which one cover acts as the biasing means. Put shortly, Ragner appears to have missed the simple and highly effective structure disclosed in the patent.
In relation to McDonald, Tristar argued that the judge had wrongly construed the document and relied upon evidence from Blue Gentian's expert, which he should not have accepted. Again, the court rejected Tristar’s arguments:
He [the judge] concluded, based upon Mr Sinclair's evidence, that the skilled but unimaginative garden water hose designer looking at McDonald would have been concerned that the proposal had not been thought through properly. I am satisfied that this was a conclusion to which he was entitled to come.
Therefore, the Court of Appeal upheld the first instance decision of Birss J and dismissed the appeal, noting:
I am satisfied that the judge has carried out a thorough evaluation of the evidence before him and he has made careful findings. He has made no error of principle. In my judgment there is no basis for this court to interfere with the conclusions to which he has come.
 EWCA Civ 746