Norbar Case Study

Hitachi Cylinder Assembly

Torquing bolts on hydraulic cylinders

Hitachi Excavators

Hitachi are a trusted name within the mining industry, especially when it comes to their Hydraulic
Excavators.

Hitachi’s reputation has been earned for their ability to satisfy demands for reliability and durability in various large open-cast mines around the world. Hitachi’s hydraulic excavators come in a number of sizes, with their largest boasting an operating weight of 800t and a bucket capacity of 40m3.

Torquing Bolts on Hitachi Hydraulic Cylinders – An Ongoing Challenge

Hydraulic Cylinders are a critical and integral part of a Hitachi Excavator. These cylinders require periodic
maintenance to ensure their safe performance and service longevity.

Torquing bolts on the Hitachi Hydraulic Cylinders has been an ongoing challenge for operators due to the
cylinder shape, size and ‘inhex’ bolt style.

For some time, Hitachi had relied on hydraulic tooling with no traditional style reaction points. An operator
would hold the hydraulic tool in place with an irregular length socket and utilise a hydraulic pump to
apply the torque, ranging from 1100 Nm to 3400 Nm. The same process would also be used for breakout.

Image: The Norbar EBT-92-4000 in use on Hitachi Hydraulic Cylinder.

Associated Risks

This method of torquing bolts, which is widely used on hydraulic cylinder servicing, had potential to significantly impact operations in two main areas:

Resource Wastage
The common practice of manually handling traditional hydraulic tooling for torquing bolts requires the Operator to set up the pump, attach the hoses and manually hold the tooling to apply torque, resulting in the task taking longer than necessary.

Service technicians were also finding they were needing to replace or repair equipment frequently, due to the difficulty in achieving ideal reaction points on radiused surfaces, often resulting in damage to tooling, fasteners and cylinders.

OH&S Concerns
Due to the nature of Cylinder overhaul, manually holding tooling in place can put operators in uncomfortable positions open to OH&S risks. This includes those associated with holding the tooling in place and working in proximity to high-pressure, hydraulic oil.

A Safer Alternative

Norbar Australia was approached by Hitachi to provide a safe and reliable solution that would both reduce damage to tooling and reduce the time taken to undertake the application.

Subsequent to an assessment of the application across a number of cylinder models, Norbar was able to recommend products that would suit Hitachi’s needs. The solution included:

EBT Cordless Torque Multiplier

Battery powered multiplier which allows operators to move freely without any bulky air or hydraulic attachments
Accuracy of +/- 3%
Programmable and traceable

Custom Reaction Arm and Nose Extensions