CONCRETE

Changing a Slew Bearing

Many times over the last 25 years HTC has been called upon by very diverse industries in New Zealand and in the Islands to provide solutions for heavy lifting, moving, and bolting.

Projects have included lifting and moving bridges, machinery, bolting test frames in place for testing jet engines and changing some of the largest slew bearings in the country.

When one of their customers needed to change a two tonne slew bearing in a 155 tonne machine on tracks they approached HTC. The project was to unbolt the slew bearing, lift the superstructure, and when the new bearing was in place, torque the bolts up and lower the superstructure so the machine could continue production.

The slew bearing was unbolted using Hydratight Sweeney RSL 2 and RSL 4 hydraulic torque wrenches which develop up to 4176Nm of torque powered by Powerteam PE55 hydraulic pumps.

The 155 tonne superstructure then had to be lifted 350mm to allow the bearing to be removed and the replacement bearing fitted and bolted into place.

The lift was made using 4 X 150 tonne locking jacks controlled by HTC’s custom made CPI controller. This lift was made more challenging as the weight of the superstructure was not an evenly spread load. To solve this challenge and ensure maximum safety and efficiency, the plumbing included check valves and needle valves to enable the finest control over this uneven load in both the lifting and lowering phases. The lift and lowering of the 155 tonne superstructure was monitored closely using calibrated digital pressure gauges fitted to each of the pumps.

HTC chose to use its Japanese made Riken SMP series pumps and valving for the lifting and lowering of the superstructure. These pumps have been tested and proven in its hire fleet for over 25 years. To complete the unbolting and torquing the new slew bearing in place, the industry standard Powerteam PE55 pump was used to power the Hydratight Sweeney torque wrenches and calibrated gauges ensured the correct torque value was applied to the bolts.

This project was completed over several weeks and the team was subjected to frosts, fog, rain, wind and dust storms with the odd bit of sunshine thrown in.

HTC bring 25 years’ of experience, and John Boyd, their most experienced sales engineer with over 20 years with HTC, has a wealth of knowledge to assist with your project. HTC always uses industrial quality tools for projects undertaken and can tailor a solution if required.

For further information contact: John Boyd, Freephone:
0800 48 2000 or Email: info@specialisedtools.co.nz