Cutting chain

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A cutting chain is a revolving link chain that is used to extract the contents of deposits . Cutting chains are used in mining on cutting cutting machines and on older types of continuous miners . Special cutting chains have been developed for cutting hard stone such as marble or travertine .

construction

The cutting chain consists of individual chain links. Each chain link consists of a specially shaped pocket or cam, the chisel holder. The cutting chisel, also known as a tooth, is inserted into these pockets. Pressure screws are attached to the side of the chisel holders to fasten the chipping chisels. The chisel holes on the individual chisel holders are offset from one another. As a result, the chipping bits are distributed over the entire width of the scraper. There are connecting straps on the individual chisel holders. The chains are riveted to one another at the connecting links or, in the case of improved chains, are connected with bolts. When connecting with bolts, repair work in the event of a chain break can be carried out more quickly. Depending on the chain design, a cutting chain has nine, eleven or thirteen rows of chisels. This enables scratches of between 120 and 175 millimeters to be achieved. Chains of the newer type with eleven or thirteen rows of chisels run better than the chains of the older type. This is due to an improved cutting process, more even cutting and coarser cutting. Also with cutting chains of the newer design the dust development is not as great as with the chains of older design. The cutting chains are up to ten meters long, depending on the size of the cutting machine.

Cutting chisel

The chisels are made of steel and have a low-wear hard metal cutting edge . Chisels made entirely from special steel are also used for softer rock. These teeth are given a special thermal treatment. During this thermal treatment, they are hardened accordingly ; at the same time, this heat treatment gives them the required toughness . The chisel types used were pin chisels and plate chisels. Chisels with hard metal tips with a cobalt content of nine to eleven percent have proven to be the best . Plate chisels have an all-round edge cut and protect the shaft from wear longer than pin chisels. They are also easier to regrind. The chisels wear out on the cutting surfaces and on the free surfaces. When cutting in hard coal , the chisels have a single stand length, that is the area that can be cut between two regrinding with the chisel, from 500 to 4500 square meters. The total stand length, that is the total area that can be cut during the life of a chisel, is between 1000 and 40,000 square meters in hard coal. The length of the tool life depends on the type and hardness of the mineral to be cut , the cutting and feed speed, the quality of the thermal treatment of the chisel and the care of the chisel. The optimal cutting chain speed is between 0.4 meters per second for copper shale and five meters per second for pure coal. With cutting chisels equipped with hard metal, the tool life is more than twenty times as long as with normal steel chisels. So that the chisels can be used long enough, they must be reground in good time. Worn teeth are replaced by new ones at certain intervals.

commitment

The cutting chain is pulled onto the cutting arm of the cutting machine and guided in a rail. When cutting, the chain must run in such a way that the cutting chisels emerge from the cutting. This pulls the cutting machine against the impact and the cuttings are conveyed out of the cut. Depending on the impact, the cutting chain must run to the right or left. The thickness of the scrape must be 175 millimeters for pressurized mountains and undulating terrain . In the case of non-pressure-sensitive mountains and levels lying flat, a thickness of 120 millimeters is sufficient.

Individual evidence

  1. ↑ a b c d e f B. W. Boki, Gregor Panschin: Bergbaukunde. Kulturfonds der DDR (Ed.), Verlag Technik Berlin, Berlin 1952.
  2. ^ A b c d Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia. 7th edition. Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  3. ↑ a b c cutting chain for cutting machines for cutting hard stone such as marble or the like. Patent No. EP0798446 November 6, 1997 (accessed on September 8, 2011).
  4. ↑ a b c d e f g Carl Hellmut Fritzsche: Textbook of mining science. First volume, 10th edition. Springer Verlag, Berlin / Göttingen / Heidelberg 1961.

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