Pick hammer
The pick hammer , also known as a pick hammer, is a pneumatic tool that is used in mining to extract coal, ores or rocks . The pick hammer was created from the hammer drill. A first forerunner was the Frankish cutting machine used in Mansfeld's copper mining in the 1890s.
history
The first hammers were used in the German coal mining industry as early as the beginning of the 20th century. The pick hammer flourished in the period after World War II. As recently as the 1950s, coal in Belgium, Germany (except Saarland), Holland and France was mainly extracted with a hammer . Already at that time, the harder and more solid coals available there were extracted by means of a cutting machine in Saar mining, British and North American mining . From the 1970s to the beginning of the 1980s, pick hammers were only used in some struts of the steeply inclined and steep storage for non-mechanical extraction. The pick hammer has only been used very rarely since the 1980s. Its use is limited to less extensive work.
construction
The pick hammer consists of the housing, the handle, the striking device, the retaining cap and the pointed iron. The impact device is located in the housing, consisting of the cylinder with impact piston and the associated control. The piston of the hammer usually has a maximum diameter of 35 millimeters. This is necessary in order to be able to make the housing slim and easy to grip. The handle is usually made of plastic in order to minimize the effects on the user caused by the recoil of the impact device. Another way to reduce the effects of vibration is to use handles with springs. There is a hose connection nipple on the handle, via which the impact device is supplied with compressed air . The operating pressure is 5 bar , the maximum pressure must not exceed 30 bar. The compressed air consumption at operating pressure is between 100 and 120 liters of compressed air per minute, depending on the hammer. The starting device with which the striking mechanism is operated is integrated into the handle. The pointed iron is held in the holding device, the holding caps. There are two types of pointed chisels, pointed chisels with shank ends and pointed chisels without shank ends. Depending on the design, a pick hammer weighs between five and fourteen kilograms. The length of the pick hammer is about 0.5 meters without the point blade. Due to the maximum piston diameter of 35 millimeters, heavy demolition hammers are longer than light demolition hammers. There are also demolition hammers with which it is possible to bind the dust created during the work. These hammers, known as wet excavation hammers, have two atomizers from which a fine water mist sprays during operation. During operation, such breakers are constantly supplied with pressurized water. For this purpose, wet demolition hammers have a compressed air connection and a special water connection on the handle. The hammer is designed in such a way that it only works when it is supplied with water as well as compressed air. The water consumption of the wet breaker is 60 liters of water per hour.
function
As soon as the inlet valve is pressed against the working cylinder by pressing the handle or opened by pressing the handle valve, compressed air enters the cylinder. The compressed air is expanded in the cylinder. As a result, the piston in the cylinder is thrown against the tip iron with great force. The supply of fresh compressed air and the discharge of the used air from the impact device is regulated by the controller. Due to the rebound and the return air, the piston is driven back into its starting position. By utilizing pressure differences, the compressed air is reversed after each impact. During the stroke stroke, the cylinder is largely vented. So that the piston is braked by a compressed air cushion during recoil, the rear cylinder chamber is not fully vented during the return stroke. The number of blows with which the percussion piston is struck against the chisel is 1500 to 2000 blows per minute. With heavy breakers, the number of blows is significantly lower. With these breakers, depending on the weight of the hammer, it is between 600 and 1200 impacts per minute.
Use and Consequences
Pick-up hammers are used for cutting or for extracting the undercut coal face. To do this, the pick hammer is pressed against the coal face at an oblique angle. The pick hammer is also used to shred large ore and rock chunks. To increase the effectiveness of the mining hammer existing ones in the mineral detachments or bad use. It is important for the durability of the hammer and for the success of the work that the hammer is pressed permanently and firmly against the mineral with every use. This application makes the recoil of the hammer less noticeable. The dust generated during work is problematic, especially when it is rock dust. Decades of work with the pick hammer lead to a pathological change in the arm joints. This condition is known as pickle hammer disease.
Similar devices
literature
- Steffen, Praun, The practical miner , Lehrmitteldienst GmbH Hagen / Essen, 4th edition 1954
Individual evidence
- ^ A b c d Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia. Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
- ↑ a b c d e f g h Fritz Heise, Fritz Herbst: Textbook of mining studies with a special focus on hard coal mining. First volume, fifth improved edition, published by Julius Springer, Berlin 1923.
- ^ RAG Foundation (ed.): Chronicle of the coal mining in the Ruhr area. P. 3
- ↑ a b c d e f g h i j k l m Carl Hellmut Fritzsche: Textbook of mining studies. First volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1961.
- ↑ Heinz Kundel: coal mining. 6th edition, Verlag Glückauf GmbH, Essen, 1983, ISBN 3-7739-0389-8 .
- ↑ Ernst-Ulrich Reuther: Introduction to mining. 1st edition, Verlag Glückauf GmbH, Essen, 1982, ISBN 3-7739-0390-1 .
- ↑ a b c d e f g h i Horst Roschlau, Wolfram Heintze: Bergmaschinentechnik. VEB German publishing house for basic industry, Leipzig 1977
- ↑ a b c d e Horst Roschlau, Wolfram Heinze, SDAG Wismut (Hrsg.): Knowledge storage mining technology. 1st edition. Deutscher Verlag für Grundstofftindustrie, Leipzig 1974, pp. 18-19.