Overhead overhaul

5 December 1999

Foundry cranes built in the 1920s have been updated for modern use. Wolfgang Reiter and Herbert Lehner report

When Steyr Commercial Vehicles decided to overhaul its 79 year old factory in Austria, three overhead cranes could well have ended up as museum pieces. Instead it was decided that the cranes, which date back to 1921, would be dismantled and completely overhauled in line with other technological improvements being made at the factory.

Steyr, a subsidiary of Munich-based MAN AG, converted its factory from a foundry for casting commercial vehicle engine blocks into a facility for constructing and testing commercial vehicle prototypes. In nine months the 4,000m2 factory has become one of the most modern development centres in Europe for this type of work, Steyr says.

R Stahl Ges.mbH Fördertechnik, the Austrian subsidiary of Germany’s R Stahl AG, was contracted to refurbish the three overhead cranes. The cranes, each with a 17m span, were dismantled from the crane runway and taken to R Stahl’s Steyregg works, 50km away.

A comprehensive eight-week renovation started with shotblasting and painting the three riveted steel lattice girders. As for mechanical components, there was life left in the end carriages, but the drives and gears had to be replaced. Drive shaft bearings were renewed and the runway wheels were re-bushed.

As part of the renovation the old crane cabins were dismantled, but not replaced. To keep the same layout of the cranes and the workshop, the bridge was covered with zinc plated gratings to replace the old wooden boards.

Two of the cranes were fitted with push-button pendant controls, which are able to travel easily along the length of the crane runway. The third overhead crane was fitted with an HBC remote control because of the layout of the vehicle workshop.

The double rail crab or trolley was completely reworked and was equipped with new R Stahl wire rope hoists, (model SH3008-20 4/1 L3) from the SH range, introduced last year. The 3.2t capacity hoists operate at a speed of 5/0.8m/min. All motors have contactor control, and frequency regulated drives.

While the crane builder restored the fixed frame, the crane runways (between 43m and 49m long) were rearranged. The most important part of this was to renovate the lateral wear on the rail head, clean the runway and apply a surface protector. Before being fixed to the runway, the cranes were tested and reinstalled, using a mobile crane to put them back up on the 8m-high runways.

It was a very challenging project made more so by the need to remove and replace the cranes without damaging them or the surrounding building.