Pneumatic multiplier of 300,000Nm output

Paul Boughton
Maintaining safe working practices and minimising downtime costs are top mining industry priorities and achieving accurate torque is important to both objectives.

Torque tools ensure the safe and secure bolting of fastenings and assemblies across a broad range of mining applications.
With its main manufacturing site at Banbury, Oxfordshire UK, Norbar Torque Tools exports 75 per cent of its production.
Orders for torque tools come both direct from mine operators, including major multinationals and from specialist mining equipment suppliers. The mining industry uses the standard torque wrenches and torque multipliers familiar in other sectors like manufacturing, but frequently has a need for specialist products that are engineered to order (ETO), sometimes because of the scale of equipment requiring to be maintained.
Norbar’s largest Pneutorque pneumatic multiplier of 300,000 Nm output was produced specifically for the mining application of releasing and re-tightening the gland nut on the rod assembly of hydraulic cylinders. Other ETO requirements for torque tools in mining include specially designed reaction arms and nose extensions to deal with deeply recessed bolts.
The range of technology for measurement and maintenance of bolted fasteners is extensive and continually developing. Leading-edge ultrasonic measurement (USM) is used for mining applications such as checking fasteners for tension during mill liner replacement. Norbar’s USM equipment can calculate the elongation and load in threaded fasteners ranging from the smallest sizes to over 15m long. The USM meter also records relaxation in a joint.
With vehicles used in mining operations, the trend has frequently been for a growth in size and capacity. The most common applications for torque tools are wheel and track bolting. Additionally, the removable teeth on dozer buckets require repeated replacement and the bolts have to be accurately torqued. Aluminium is banned underground because of danger from sparks, so Norbar’s torque tools used to maintain specialist underground vehicles need to be either all steel or manufactured from specially coded aluminium that doesn’t spark.
The expansion of mining has meant an increase in the vehicle fleet and the requirement for tools such as Norbar’s powerful 2,000 N.m to 3,000 N.m torque multipliers for large wheel fastenings has consequently also grown. These tools offer high performance coupled with low noise and vibration levels for an improved working environment. 

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