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Photo | Hirschvogel Eisenach GmbH

The hot steel blanks now lie directly on the belt during transport.
Photo: Hirschvogel Eisenach GmbH

Hot as iron

Sprocket chains from Rexroth Pneumatics transport glowing hot steel blanks with hardly any wear and tear.


The German company Hirschvogel Eisenach GmbH produces automobile components for renowned car manufacturers and concentrates on shaping solid steel. Punctual delivery of products of the highest quality is vital to the company; reliable production means are a must. The rapid tempo in its three-shift operations, coupled with the extreme environment generated by steel forming, makes high demands on all the components used for manufacturing. A special challenge is moving the red-hot items from one processing station to the next. This is why Hirschvogel Eisenach GmbH places its faith in rugged sprocket chain conveyors supplied by Rexroth Pneumatics to link its new production equipment.

Tough conditions

Machines like drop forging presses are designed to withstand tough conditions and are engineered to be rugged. However, deformation, guide problems and high levels of wear and tear occurred when using apron conveyors. One reason: the heat. Today, these red-hot steel blanks, still in the 1,200 degree range, are transported right on the sprocket-type chains supplied by Rexroth Pneumatics. These are up to the job, being made of quality tempered steel. They run on sprockets made of vacuum-toughened tool steel. Due to their slat-shaped design, they expand only slightly, while the special tooth profile prevents damage to the “freight”.

Hardly any wear and tear

As a result of the heat, the steel blanks form scale which flakes off during transport, floats downward, and accumulates on the sprocket chain links. To minimize wear and tear, the chains are cleaned by additional disks each time they pass over the sprocket. This guarantees reliable functioning and long chain life. And this is achieved without lubricants in spite of the high speed of one meter per second. Lubricants would carbonize in the heat and cause further grime.

The longest chain used at the Eisenach plant is ten meters long, with sprocket centers five meters apart. This long distance and the fact that workpieces are frequently moved at right angles to the conveyor made it necessary to reinforce the guides for the chain. This provides more stability and lengthens life spans, since there is less abrasion to the guide shackles.

Dennis Reinhardt, a member of the maintenance team at Hirschvogel Eisenach GmbH, is thoroughly excited. “We used to replace the conveyor every three months. Nowadays, we merely exchange the conveyor’s sprocket chains in the course of scheduled annual plant maintenance and the conveyors have to be replaced only every two years.”