Caster crown
A Schrämkrone is a tool , which on column shearers was used. There were up to five different types of cutting crown.
construction
The cutting crowns are made of tool steel and have hardened cutting edges at the top . The cutting edges of some types were interchangeable. In this way, worn cutting edges could be replaced with new cutting edges by the cutting tool on site without the need to replace the cutting head. For this purpose, the old cutting edges were knocked out of the side of the cutting crown and the sharp cutting edges were knocked in again. The crowns were 65 to 90 millimeters long, depending on the type of crown, and had between three and eight cutting edges.
commitment
Crowns with three blades shred the mountains very little and tend to a close Schram clamp. Multi-edged crowns are easier to use and do not tend to jam, they also work better free in the Schram. Multi-pointed crowns are particularly suitable for tough coal. Even coal , with pyrite is crisscrossed can be better handled by the vielspitzigen crowns. Due to the backsliding caused by cutting, the heights of the cut that can be created with these crowns are between 75 and 120 millimeters, depending on the type of crown.
Individual evidence
- ↑ a b c d e Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, fifth improved edition, published by Julius Springer, Berlin 1923.
- ↑ a b c d e Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, published by Julius Springer, Berlin 1908.