Patent for power tool vibration monitoring device upheld by Outer House 

Reactec Ltd originally brought an action against Curotec Team Ltd seeking interdict against patent infringement on the ground that two of its products had infringed their patent. Curotec counterclaimed that the pursuer’s original patent, granted in 2013, was invalid. 

The case was heard in the Outer House of the Court of Session by Lord Doherty. 

Monitoring hand-arm vibration 

The original patent was entitled “Monitoring Apparatus for Monitoring Hand Held Tool.” The pursuer used this patent in a device designed to assess the vibrations produced by power tools over a period of use, in particular hand-arm vibration experienced by the user which could lead to long-term illness, such as white finger, following regular long-term exposure. 

The monitoring component was capable of being attached to and removed from handheld tools via a mount that the monitor could itself be detached from and was more accurate and reliable than previous measuring apparatus that had been patented. It also contained a Radio Frequency Identification tag which held information relating to the tool.  

The patent was addressed to a skilled team, including an electronic engineer and other members. The exact makeup of the team was disputed by the parties, but the court was persuaded that the skilled team was to include an electronic engineer and either a mechanical engineer or a physicist with a background in vibration. 

The defender sought to invalidate the patent on the ground that it did not involve an inventive step as the claimed step was obvious to a skilled team in light of the state of the art at the priority date, agreed to be 23 December 2005. 

Two previous patents were considered in detail: a British Gas vibration assessor consisting of a wrist-worn device linked to a device mounted on the tool with an RF transmitter, and a Bruel & Kjaer device designed to be wrapped around a tool. 

The pursuer argued that the BT patent differed in that the monitor was worn on the wrist instead of mounted on the tool and did not contain an RFID tag. The Bruel & Kjaer device, meanwhile, was not designed for everyday use but for one-off measurements by specialist users rather than typical tool operators. 

Not obvious to a skilled team 

In his opinion, Lord Doherty found it useful to go through the Windsurfing/Pozzoli test for identifying whether the disputed inventive step was obvious. Identifying the relevant skilled person, he said: “While it is possible that the skilled person who is the addressee of the Patent and the skilled person for the purposes of considering obviousness may not always coincide it was not suggested that that was the case here. Both parties proceeded on the basis that the skilled team ought to have the same composition for both purposes.” 

He continued: “In my opinion the skilled team comprised a physicist or mechanical engineer with knowledge and experience of vibration monitoring and an electronic engineer.” 

On the inventive concept of the claim, he said: “The inventive concept of the claim is (i)that the vibration monitor is releasably mounted on the tool; (ii)that a timer operates in dependence on the vibration signal to record the duration of vibration; (iii)that the mount contains a passive RFID tag holding information relating to the tool, including information on vibration; and on being connected to the mount, the monitoring component actuates the RFID tag and reads the information.” 

He continued: “While in one sense it is fair to say that the two features do function largely independently, I disagree with [the defender’s] conclusion that there was no interaction. The information relating to the tool, including information on vibration, and the duration of vibration are both essential in order for the apparatus taught by the claim to arrive at vibration dosage for the operator.” 

Regarding the differences between the claim and the prior art, he said: “It is common ground that at the priority date RFID technology was widely used for bar coding, magnetic swipe card technologies, systems for identity verification and asset management, and systems for inventory control, but that it had not been used in any vibration monitoring apparatus.” 

He continued: “It is clear on the evidence that if the step of mounting the monitor on the tool was not taken, using RFID to communicate between the British Gas mounted unit and the wrist worn monitor would not have been obvious to the skilled team. On that scenario the use of RFID would not have been a technical improvement over the British Gas patent.” 

Of the Bruel & Kjaer device, he said: “The Bruel & Kjaer meter was a device designed to take representative measurements of the vibration magnitude of tools over short periods, often with a view to those measurements being used as the predetermined vibration magnitudes associated with those tools. In my view, the skilled team would have read the Bruel & Kjaer documents with interest, but then decided that they were of no interest to it as a basis for developing a vibration monitor suitable for measuring an operator’s vibration exposure.” 

Lord Doherty concluded: “The fact is that in some cases taking a combination of steps would not have been obvious to the skilled person who, by definition, lacked any invention. In my opinion that is the position here. The inventive idea was to combine the integers of claim 1 to produce an improved and more efficient monitoring apparatus.” 

For those reasons, Lord Doherty concluded that the patent was valid. In light of this, it was also found that the devices manufactured by the defender infringed on the pursuer’s patent, with the case put out to order to discuss an appropriate interlocutor to give effect to the decision.