Product category:
Gears, brakes, couplings and engines
News Release from: Brevini | Subject: Planetary geared winch units
Edited by the Engineeringtalk Editorial
Team on 04 December 2003
Planetary geared winch units provide a
lift
Compact high-torque planetary geared winch units have enabled Balfour Beatty to meet weight and power targets for a custom-designed crane used to erect electricity pylons on soft waaterlogged ground.
Brevini's range of compact high-torque planetary geared winch units have enabled Balfour Beatty to meet weight and power targets for a custom-designed crane used to erect electricity pylons on soft waterlogged ground Two Brevini units are used, one to lift the crane's boom and a second acting as the hoist winch
Both winches are required to operate reliably in high winds and extreme conditions as the crane is used to restore power after outages in bad weather.
The special application crane is designed to maintain HV power lines in Argentina that run for over 1600km, often over difficult terrain.
The design specification requires the crane to lift 500kV towers weighing over 8t, while standing in 2m of flooded Pampas ground.
The unit itself is not self-propelled in order to reduce weight, also keeping the design simple and maximising its reliability in the field.
This philosophy is implemented throughout the design and is the reason for selecting Brevini's TNE Model of compact winch units.
The TNE design combines small hydraulic or electric motors with planetary gear stages to increase torque and reduce weight, making them an ideal choice for this application.
The drive arrangement also minimises the torque stress within the system by using smaller, faster drive elements and distributing any point pressure across many planet gears.
The result is a very reliable winch drive capable of withstanding high loads without the risk of failure associated with larger motors and gears handling more individual torque.
The arrangement is also highly efficient at over 98% per stage.
Rob Sonnex who is responsible for designing and building the Athey crane (named after the original tracked Athey logging trailer used to build the first version of this type of crane) had an existing drum to work with on the boom winch and asked Jon Snaith at Brevini UK to provide a solution.
"Line speed was important here as the time taken to hoist these pylons is just 30min, compared to the full day it takes to erect European style four leg pylons.
We achieved 39m/min line speed with a continuous 5t load using a three stage planetary reduction, an adapter plate and a hydraulic piston motor of just 90cm3.
We were also able to incorporate a fail to safe multi-disk brake at the input shaft".
Safety was a major consideration in this application.
The winch brakes are specified with a 10t capacity to compensate for wind loading, as the crane is used to restore power lines and pylons that have been blown down in storms and conditions can still be fairly inhospitable when they are being erected.
A two part hoist is used to lift an SWL of 10t.
The hoist winch is a TNE 6000 unit that incorporates the drum, drive and brake mounted onto an A-frame.
The advantage of this is that the design arrangement is fully tested and thanks to a modular build process can be specified to suit the parameters of the application exactly.
Fitting is also made remarkably easy as the entire unit can simply be bolted to the structure.
Once the cable is attached and hydraulic motor is piped in, it is ready to go.
Brevini UK is increasingly called on to design and supply complete drive systems due to its ability to combine a range of geared and hydraulic elements to achieve and ideal solution, all from within the UK group company.
The product range includes planetary, bevel and worm gear solutions alongside hydraulic pumps, motors and controls.
Brevini in the UK carries out all design, commissioning and servicing.
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