Tracked vehicles are a mainstay of mining but these diggers, graders, scrapers and exploration vehicles have an inherent weakness that comes from their strength.
This weakness is that they are usually heavy and need top-notch maintenance of their many linkages to operate safely in the rough.
Rather than rely on traditional flogging spanners for the dozens of bolts involved, with the associated hazards for people and from unevenly torqued nuts, Enerpac has introduced a new series of compact torque wrenches that apply the power and precision of 700 bar hydraulics to the task.
The S and W series of compact high-pressure hexagonal and square drive torque wrenches, complemented by Enerpac’s pumping technology, combine durability, reliability and safety with rigid steel design and solid power-to-weight ratios.
The S series of double-acting square drive wrenches extends from 2.7kg to 31kg with outputs of 1898Nm to 34437Nm, while the W low profile hexagonal wrenches for low clearance bolting applications weigh from 1.4kg to 5kg and provide precisely repeatable torque from 27,12Nm to 20,337Nm.
The W wrenches’ small nose radius measurements of 31mm to 87.5mm ensure they fit readily into tight spaces with their hexagon range from 36mm to 115mm. The S models offer from 25mm to 63.5mm, with the square drive ranging from " to 2.5".
The tools weigh from 3kg to 31kg and 2kg to 15kg respectively yet exert high and repeatable forces.
Enerpac bolting product manager Pat Molloy says of the many bolts that need correctly tensioning, the critical ones for safety are any bolt that is related to steering or suspension in both crawler and conventional wheel vehicles, and all bolts on tracks.
“The track bolts, particularly, cop a tough time from the types of roads, or lack of roads, on which they operate, and from the loads that they carry,” Molloy says.
“Other bolts that tend to come loose if not correctly tensioned are any cutting edges that are face-hardened to prevent wear. These often need changing as part of routine maintenance where they are involved in the hard yakker of mine sites,” he says.
“Any bolt that may come loose causes downtime and if not spotted in time can cause failures in equipment.
“Correct torque values greatly assist in the prevention of such failures, but the use of flogging spanners to achieve such values is a very time-consuming and expensive exercise.
“Flogging spanners are hit and miss because human error and the elements control the tension you put on these bolts. The potential for hazard and error is obvious when you consider that flogging spanners are just a spanner fitted to the bolt and hit with a sledgehammer.”
Molloy says in some circumstances this method is an accident waiting to happen.
Features of the S series square drive torque wrenches include:
360º click-on, multi-position reaction arm and push-button square drive release to quickly reverse the drive for final tightening or loosening. A fine tooth ratchet prevents tool “lock on”
Compact, high-strength, nickel plated uni-body construction for a small operating radius. The robust design with minimal parts facilitates easy on-site maintenance without special tools
Lightweight ergonomic design for easy handling, with an optimised strength-to-weight ratio and fast operation because of the large nut rotation per wrench cycle (35º rotation angle and rapid return stroke).
Features of the W series include:
Fast operation from large nut rotation per wrench cycle (30º rotation angle and rapid return stroke). No tools are needed for changing heads
Pinless wrench construction incorporating quick release cylinder and automatic crank engagement. Robust design with minimal parts for easy on-site maintenance without special tools
Cylinders and low profile heads engineered for slim, compact, low clearance tooling with a small nose radius.
Constant torque output provides high accuracy across the full stroke of hexagonal and square drives. An in-line reaction foot ensures accuracy by reducing internal deflections in the hexagonal drives, while uni-body construction ensures accuracy in the square drives by reducing internal deflections.
Both torque wrenches come with a wide range of accessories for safety and efficiency in particular applications, including twin 4:1 safety hoses.
Both can be used with a wide range of optimum electric and air pumps, including the latest cool-running and energy-saving ZU4T hydraulic torque wrench pumps designed for bolting applications.
The compact and highly portable ZU4T series electric pumps, which weigh between 32kg and 36kg, offer auto-cycle for continuous cycle operations and quick, secure coupling by way of Parker spin-on-couplers for 700 bar models and Enerpac lock-ring couplers for 800 bar models.
The high-efficiency two-speed pumps have higher oil flow and bypass pressure (85 bar) for cooler running and require 18% less current draw than comparable pumps.