Patents - Kwikbolt Ltd v Airbus Operations Ltd

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Jane Lambert

Intellectual Property Enterprise Court (HH Judge Hacon) Kwikbolt Ltd v Airbus Operations Ltd [2021] EWHC 732 (IPEC) (25 March 2021)

This was an action for an injunction, damages and other relief against aerospace manufacturer Airbus Operations Ltd, for patent infringement. There was also a counterclaim by Airbus for revocation of the patent on grounds of lack of novelty, obviousness and insufficiency. The action and counterclaim came on for trial before His Honour Judge Hacon between 9 and 12 Feb 2021. In Kwikbolt Ltd v Airbus Operations Ltd [2021] EWHC 732 (IPEC) (25 March 2021) His Honour held that the patent was valid but that it had not been infringed. 

The Patent

The patent in suit is GB2455635B.  It was granted for a removable blind fastener.  The title might suggest that the invention has something to do with window blinds in an aircraft  cabin, In fact 

"'Blind' is a term of art in the context of fasteners, meaning that the fastener can be fitted from one side of the workpiece, essential if the technician only has access to one side"

as the judge pointed out in para [1] of his judgment.  The "fastener" in this context is much more like a rivet in shipbuilding as can be seen from the following abstract.

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"A removable blind fastener 1 comprises a first member having an elongate body 11 with a head 12 at one end and a second member 20 having an elongate body extending from and adapted to slide relative to the first member. The second member 20 has at least one flexible finger 22A, C with a finger head at one end remote from the first member. A screw member 30 has a screw head adjacent the first member head 12 and a screw shaft 33 which passes through the first member and engages with a threaded aperture on the second member20. Rotation of the screw member 30 in one direction causes the second member 20 to slide towards the first member and biases the or each flexible finger 22A, C radially outward. Rotation of the screw member 30 in the other direction causes the second member 20 to slide away from the first member and allows the or each flexible finger 22A, C to move radially inwards. In use the fastener 1 is insertable through an aperture 40A, 50A in each of two workpieces 40, 50 which need joining together with the 12 head of the first member located against a face of one workpiece 40. Rotation of the screw member 30 causes the or each flexible finger 22A, C to expand radially outward so the finger head on the or each finger engages a face of the other workpiece 50 and causes the two workpieces 40, 50 to be drawn together as the second member 20 slides towards the first member."

The judge described how the invention worked between paras [23] and [29] of his judgment.

The Claims

The claims alleged to have been infringed and whose validity was challenged were 1, 8, 16 and 18.  The judge discussed them between paras [30] and [33].

Skilled Addressee

His honour identified the skilled addressee ay [34] as "an engineering technician, typically employed in the aerospace industry, with practical experience in the use of temporary fasteners for product manufacture and maintenance."

Common General Knowledge

It was common ground "that the skilled person's common general knowledge would have encompassed a variety of both permanent and temporary fasteners."  Airbus pleaded a list of matters that were alleged to have formed part of the skilled addressee's common general knowledge.   Except for one item known as the "E-Nut" that list was unchallenged.  The learned judge found as a fact that the "E-Nut" did not form part of the skilled person's common general knowledge.

Construing the Claims

Judge Hacon referred to the Supreme Court's judgment in Eli Lilly v Actavis UK Ltd and others [2017] Bus LR 1731, [2017] UKSC 48, [2017] RPC 21.  He directed himself to decide what each claim meant in accordance with the general rules of construction of a document which is sometimes called the "normal construction" of a claim.  Referring to the Court of Appeal's decision in Icescape Ltd v Ice-World International BV and others [2018] EWCA Civ 2219 (10 Oct 2018) the judge added:

"It is a purposive construction, the inventor's purpose being ascertained from the description and the drawings as they would be understood by a person skilled in the art with the common general knowledge in mind."

His Honour also directed himself that if a product or process does not infringe the claim as a matter of normal construction, the analysis moves to the second question which is whether the product or process nonetheless falls within the scope of the claim because it varies from the invention according to the normal construction in a way or ways which is or are immaterial.


He analysed claims 1 and 16 according to the normal rules of construction between paras [40] and [79]. He next considered whether Airbus's product (a drawing of which appears at the gear of the page) had the integers that he had identified in his analysis,   He concluded at [91] that Airbus's fastener did not infringe on a normal construction because features of the claims were missing.

Having referred to para [66] of Lord Neuberger's judgment in Eli Lilly, the learned judge considered each of the reformulated Inprover questions,  He concluded at [111] that Airbus's product did not achieve the result of the inventive concept at all.  It followed that the defendant's fastener did not exploit the inventive concept of claim 1.  Accordingly, the patent had not been infringed even under the doctrine of equivalents.

Lack of Novelty

The prior art relied on by Airbus for its contention that the patented invention was not new was a US patent application for an "Expandable collet anchor system and method" numbered 2005/0169726 A1 ("McClure 1") and an item called "the E-Nut" which was alleged to be a specific embodiment of McClure 1.  The judge considered McClure 1 between para [126] and para [142].  He concluded at [143]:

"In my view there are no clear and unmistakable directions in McClure 1 to the invention of claim 1 because there is no disclosure of a fastener which is suitable for removal as a unit. On the contrary, the skilled person would understand that the sleeve insert should be secured to a workpiece. Claim 1 does not lack novelty over McClure 1. "


Referring to the skilled addressee and the common general knowledge which I have mentioned above, Judge Hacon said that the principal difference between McClure 1 and claim 1 of the patent in suit was that there was no teaching in McClure 1 that the sleeve insert should be removed and thus that the fastener as a unit is removable. In fact, a key teaching of McClure 1 is to anchor the sleeve to the workpiece so that it cannot rotate in use. In His Honour's view, the skilled person would not have thought it obvious at the filing date to abandon that central feature of McClure 1 which is necessary for the fastener to work. Consequently, claim 1 did not lack an inventive step over McClure 1.  The same was true of claims 8, 16 and 18.

Turning to the "E-Nut" the judge said that it was a physical embodiment of one of the versions of the fastener disclosed in McClure 1. The sleeve insert/first member of the E-Nut must be glued to the underside of the upper panel or workpiece. The collet body/second member is pushed into the sleeve insert, after which the screw is rotated into the collet. The sleeve insert is not removable. Further, it was admitted in cross-examination that the E-Nut was not a blind fastener because access is required to the far side of the workpiece in order to install it.  His Honour concluded at [149] that the "E-Nut" added nothing to McClure 1.

The learned judge considered McClure 2 between paras [150] and [156].  He concluded at [157]:

"This idea of isolating the collet fingers from the torque moment of the screw to avoid damaging the fingers and the workpiece seems to me to have been central to the inventive concept of McClure 2. It is also the principal difference between McClure 2 and the Patent. I do not believe that it would have been obvious to a person skilled in the art to abandon the key teaching of McClure 2 and instead have the collet moved by receiving the screw into a threaded aperture within the collet (the second member). Claim 1 does not lack inventive step over McClure 2."

The same was true of claims 8, 16 or 18.

The judge addressed Wylie between [159] and [175].  He could not see how Wylie could work in the way suggested by Airbus and concluded that claim 1 of the patent was not obvious over Wylie.  Wylie had been a very old piece of prior art but that did not mean that it could not be relevant.  His Honour said at [177] in passing:

"Even if a piece of prior art is old, the hypothesis is still that the skilled person will read it with care at the filing or priority date. If an obvious modification to the prior art would occur to the skilled person, such a modification is not taken out of consideration for inventive step solely because the skilled person would believe that modified or not, this old piece of prior art would have little practical or commercial use as of the filing or priority date."


An argument on insufficiency had been based on a schematic diagram.  In the course of the trial, it was agreed that the diagram would not be taken literally and that the invention could be implemented.


As the anticipation, obviousness and insufficiency attacks had failed, Judge Hacon concluded that the patent was valid.   Anyone wishing to discuss this case or any of the topics raised in it may call me on 020 7404 5252 during office hours or send me a message through my contact form.


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