Norbar torque tool for London Underground 15 February 2022

Norbar has developed a unique torque tool for the London Underground to help with the removal and refit of the inter-car coupler mounting bolts on the fleet of 47 Bombardier 09 Stock trains used on the Victoria Line.

The inter-car coupler mounting bolts are accessed from the underside of the train, either from the pit road or with the train jacked up. The coupler mounting has four bolts with a significant boss in the middle that houses the Absolute Position Reader (APR). Of the four bolts, the upper two were particularly difficult to access due to them being deeper up into the train and surrounded by other hardware. However, the bolts are required to be tightened to a torque of 1,050Nm. London Underground’s tool supplier, Hayley Group, contacted Norbar Torque Tools Ltd with the remit of providing one tool to reach all of the bolts on the coupler.

The Norbar solution was to use a Pneutorque® PTS tool with a specially developed drive that is slim, long and offset from the PTS square drive, with a series of gears arranged in-line and driving each other. This enables all of the bolts to be reached during maintenance.

In addition, the gearbox of the tool is supplied with quickchange reaction arms in order to reach all of the bolts and safely take torque reaction from the tool. The aluminium bodied gearbox can also be positioned on the bolt before the driving tool is coupled. This significantly reduces the total weight that has to be lifted and makes the location of the offset gearbox and its reaction plate much easier.

Philip Brodey, head of new product development at Norbar, commented: “We chose the pneumatic Pneutorque PTS tool as the basis for the specialist torque wrench due to its quiet and smooth power source allied to its accurate torque delivery. The development was a complex process that involved the use of a 3D printed model to ensure the tool could reach the bolts required. We were able to develop one tool that reaches all of the bolts whilst retaining power, accuracy and safety for the operator.”   

Deputy Editor

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

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Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

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