Mantle head nuts with brains

NEW mantle head nuts make changing-out head nuts a safer, shorter operation.

HEAD nuts are typically tightened manually during crusher service or mantle liner change-outs. However, this practice sometimes requires sledge hammers and lug welding equipment.

This can be dangerous and can cause lengthy delays during change-out.

A quarrying and mining equipment manufacturer has developed a solution that could eliminate this practice.

Terex Jaques has released a head nut system that safely tightens head nuts on cone crushers.

“Previously the user had no control on the head nut torque, and it took great effort to install and tighten the head nut,” Terex Jaques senior engineer Merv Tracey said.

“The product removes injury risk and does not require physical force to install or tighten,” he said.

The company’s head nut system is a hydraulic clamping nut that is torqued to precise tensile load.

The technology includes integrated mechanical locking rings and a sacrificial protective cover.

The unit is only marginally larger than a traditional mantle head nut and does not interfere with material cascade or crusher throughput.

The unit is reusable and includes a protective outer-sacrificial sleeve designed to wear slower than mantle lining manganese.

Fitting to a clean shaft takes about 30 minutes.

“Belting-up a head nut used to be hard enough and loosening was even harder,” Tracey said.

“As manganese expands with wear it often requires oxy acetylene cutting to loosen it. Head nut installation could take hours,” he said.

Karreman Quarries manager Danny Karreman was impressed with the product’s performance.

“We’ve had it fitted in a crusher in normal operating conditions and haven’t nursed it or put it under undue stress and it has held up well,” Karreman said.

“From an OH&S point of view it is fantastic, but from a time frame point of view the product will cut the change-out time in half, which increases productivity,” Karreman said.

“During operation it has not tightened up on the manganese.”

The product is beneficial for smaller operations, as they generally need to pull down cone crushers every six to eight weeks to replace the manganese.

The system can be used on any crusher with details of shaft thread size.

“Some primary gyratory crushers used in mine sites with mantle head nuts up to 60 cm need to have the entire shaft removed,” Tracey said.

“The crushers work on head nuts with specialty equipment and the product can be adapted to suit these machines,” he said.

Terex Jaques

John Flynn

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