Dropper post
A lowering support is a flexible support element that is used in mining instead of the extension segments on the butt side of the line extension . Plumbing supports used in mining must be approved by the mining authority .
Layout and function
The dropper post is box-shaped and open at the top. The housing of the dropper column is made of sheet steel bent into a rectangular profile . The prop has a length of 0.8 to 1.8 meters. The ends of the sheet are welded together. A sheet steel base plate is welded to the lower end of the drop. A small steel brake shoe is mounted in the sheet metal housing. This brake shoe has a brake lining made of wood and is used to support and guide the expansion segment. When the brake shoe is loaded, the brake lining attached on one side presses against a wooden wedge mounted in the drop bracket. The extension segment is placed on the brake shoe so that it protrudes at least 0.3 meters into the support. The brake shoe applies a certain insertion resistance due to the friction between the wood and the brake shoe. This resistance is increased by the friction between the stamp foot and the plunger. In addition, the work of deformation between the brake lining and the wooden wedge increases the insertion resistance. This insertion resistance counteracts the rock pressure . The inner construction of the dropper column gives the extension a certain flexibility. This resilience is maintained until the punch reaches the footplate. Depending on the length of the prop, the insertion paths are between 0.5 and 1.5 meters. The support also gives the extension a slight flexibility to impact pressure. The impact pressure in the dropper post causes the brake lining and the wooden wedge to be deformed. This deformation of the braking elements lifts the extension segment slightly from the dropper post. As a result, the extension segment sinks a little into the prop. Drop supports therefore work on the principle of material deformation and flexibility.
Special features and use
It is possible to preload the extension of the route by using drop supports. This counteracts the loosening of the mountains. A special setting device is used to achieve a permanent pre-tensioning of the extension. Senkstützen be in rigid arch support , in hinged arch expansion , and when the articulated frame timbering used. For this purpose, the props are burned into the lying position. The combination of support and vertical support is referred to as support support. Prestressing of the vertical supports was common in the Dutch mining industry.
Individual evidence
- ^ A b Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary. 7th edition. Glückauf Verlag, Essen 1988, ISBN 3-7739-0501-7 .
- ↑ District government Arnsberg: Approval of plumbing supports online (accessed on December 23, 2011; PDF; 321 kB)
- ↑ Horst Roschlau, Wolfram Heinze, SDAG Wismut (Hrsg.): Knowledge storage mining technology. 1st edition. German publishing house for basic industry, Leipzig 1974, p. 87.
- ^ A b Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition. Springer Verlag, Berlin / Göttingen / Heidelberg 1962.