Shenzhen Carku Technology Co., Ltd v The Noco Company

In patent infringement and validity proceedings, equivalence is assessed by identifying the inventive concept and applying the structured approach in [2017] UKSC 48. The specification, common general knowledge and deliberate use of narrower claim language may show that a variant falls outside the claim, even where it performs the same function.

A claim requiring a reverse polarity sensor requires a sensor capable of detecting a battery connected with incorrect polarity. A claim for a manual override of a vehicle-battery isolation sensor does not necessarily require the reverse polarity sensor to be overridden. Communications to an online marketplace may constitute threats where, objectively, they indicate intended infringement proceedings against the marketplace or another person.

The claimant sought revocation of the defendant’s patent for a battery-powered vehicle jump starter. The defendant counterclaimed for infringement. The claimant also alleged that notifications made by the defendant to Amazon under its intellectual property complaints procedure were actionable threats under sections 70 and following of the Patents Act 1977.

The principal issues concerned claim construction, infringement by equivalence, obviousness over three items of prior art, and whether the Amazon communications amounted to threats of patent infringement proceedings.

1. Claim construction. A “reverse polarity sensor” must be capable of detecting that a battery is connected with incorrect polarity. A vehicle-battery isolation sensor, which cannot distinguish reverse polarity from absence of a battery or very low voltage, does not satisfy that requirement. The claim language did not require sensor checks to occur immediately before the connection was closed. “In response to” meant as a result of, not instantaneously.
2. Manual override. Claim 19 required an override of the vehicle-battery isolation sensor. It did not state or imply that the reverse polarity sensor had to be overridden. The claim was a “but” dependent claim, requiring the same physical components but permitting different behaviour. The narrower reverse-polarity safeguard described in the specification was an optional feature, not a requirement of claim 19.
3. Equivalence. Applying [2017] UKSC 48, the inventive concept of claim 1 was functional and concerned the use of isolation and polarity signals to control connection of the power supply. Nevertheless, a relay was not equivalent to the claimed power FET switch. The specification mentioned relays in the prior art, broader “switch” language was available but not used in the claim, and the claim descended to physical detail in relation to the switch. A separate microcontroller connection point used in Family C products was equivalent because the relevant logic and function remained unchanged and the specification gave no positive reason to exclude that variant.
4. Validity. The patent was obvious over the Projecta manual. It was obvious to implement its safety-focused override so that a severely depleted or absent battery could be bypassed while reverse polarity remained protected, and the use of two discrete sensors was a routine implementation choice. The patent was also obvious over Richardson, including because the delay before connection was not excluded by the claim and, alternatively, removal of the self-contained ignition-voltage-drop feature was an obvious simplification. The attack based on Krieger failed, principally because its separate teachings could be assembled into the claimed relationship only with hindsight.
5. Threats. Under sections 70 to 70C of the Patents Act 1977, the question was objective and depended on all relevant circumstances known to the recipient, including Amazon’s commercial procedures. The communications asserted patent rights and infringement and requested removal of identified products. They amounted to threats against Amazon and, in any event, indicated intended proceedings against third-party distributors. The patent was invalid, so the statutory justification defence failed. An inquiry as to damages was ordered; the scope of injunctive relief was to be addressed at a further hearing.