There are over 200 000 km in Germany alone covered with roadmarkings. And Wachendorff encoders are the ones to ensure their precise application.
White lines at the edge of the road or in the centre of the carriageway are an important safety factor and ensure clearly visible traffic flow and improved orientation for drivers.
The rules concerning how and where these road markings are to be applied are well defined in Germany in the road traffic regulations and relevant directives. Precision is of immense importance and the application of these white lines is a factor that needs to be costed in during road construction.
Marking needs to be done correctly the first time round, otherwise the paint has to be laboriously removed; this not only costs money but normally results in considerable traffic delays. This means that both the men and their machinery have to work very accurately.
The markings are made up of a wide variety of substances: some need to be heated, others have two components that need to be mixed together immediately prior to application. Finally, for light reflection purposes, very small glass beads are scattered over the damp material. The roadmarking machines are complex and have to be both rugged and able to work with high accuracy.
A world leader in this market is the Hofmann company from Rellingen, near Hamburg, which has been manufacturing road marking machines since 1952. Hofmann supplies a wide variety of machines from small hand-controlled machines up to high-performance roadmarking trucks that can hold up to 3000 litres of sprayable thermoplastic compound. This family business is always making the news thanks to its innovations – for example, its machines were the first in the world to be able to work when the road bed is damp or wet. 90% of all the machines they manufacture are exported.
In Rellingen they prefer generally not to rely on off-the-shelf components. Their vertical range of manufacture is impressive; around 100 highly-qualified workers produce in house the majority of individual components that are used in their machines. One of the rare exceptions to this: an encoder, supplied by the Wachendorff company.
Wachendorff, also a family business, based in the Rheingau, has a company philosophy similar to that of Hofmann; it designs and manufactures its own encoders in-house, to a large extent by hand and with the utmost care and attention, so that it is able to meet the high quality requirements of its Rellingen-based customer.
Encoders are essential in marking technology, as they provide precise information regarding the distance covered – after all, when it comes to a dashed line in the centre of the road, all the dashes should be exactly the same length. The Wachendorff encoder used in the Hofmann machines is based on the standard model WDG 58B; however it has been customised in line with the wishes of the Hofmann company, featuring a longer, re-inforced shaft and special bearings. The housing has also been slightly modified and is equipped with a socket that accepts a plug connector used in all Hofmann machines.
“We were especially impressed by the ruggedness of the Wachendorff encoders”, says Jens-Uwe Eymers, control engineer at Hofmann. Not only is the encoder in later use subjected to the effects of weather and vibration – but it itself acts as a bearing and must tolerate high loads. “In our experience it is the Wachendorff devices that best withstand the challenges of high loads, vibration and adverse weather conditions,” he comments, making the point that this is the reason why his company insists on the devices from the Rheingau.
However, even the standard encoders featured in the Wachendorff catalogue can tolerate extremely high loads. Their design combines precision mechanics and a compact optical track with high-performance noise-resistant electronics. They also boast a high level of protection and a very wide operating temperature range. This makes Wachendorff encoders very rugged.
The WDG58 series of encoders is available with up to 25 000 pulses per revolution. The high resolutions of 10 000, 12 500, 20 000 or 25 000 ppr for the hollow and solid shaft encoder series WDG58 allow for very precise measurement.
For more information contact Brian Howson, Vepac Electronics, +27 (0)11 453 1910, [email protected], www.vepac.co.za
| Tel: | +27 11 454 8053 |
| Email: | [email protected] |
| www: | www.vepac.co.za |
| Articles: | More information and articles about Vepac Electronics |
© Technews Publishing (Pty) Ltd | All Rights Reserved
printer friendly version