Bumper

A bumper beam , also bounce bar called, is a component which has the task of the path of the conveyor basket or buckets and the counterweight in the event of a fault to limit upward. In German mining, impact carriers are required for main ropeway systems and goods handling systems with a travel speed of more than 4 m / s. In the Austrian mining industry, bumpers are required for ropeway systems that have a travel speed of more than 2 m / s.

need

Normally, the cages are braked in time before the attacks, so that they no later than at the pit bank or at the lowest sole grind to a halt. However, when conveying the shaft , an error can result in the conveying cages not coming to a standstill at the corresponding stops. If the hoisting cage moves over the top stop (hanging bench) due to overdriving or underdriving, it will inevitably move under the pulleys if it is not prevented beforehand . So that the kinetic energy of the hoist cage is reduced beforehand, appropriate safety devices such as limit switches and overdrive safety devices are installed in the hoistway tower and in the shaft sump . Although the cage is braked in front of the pulley due to these safety devices, there must also be a safety device for the worst case . This safety device is provided by the impact carrier attached to protect the pulleys.

Design and installation

Bumpers serve to protect the sheaves from damage by the conveyor. They must be designed and dimensioned in such a way that they can safely stop the conveyor or counterweight if they are overdriven. They are attached below the pulleys. The bumpers must be attached below the pulleys so that the intermediate harnesses and rope bindings have free passage. The distance between the bumpers and the pulleys must be so large that the cable bindings cannot run onto the cable carrier or the pulleys even if the conveyor or the counterweight hit the baffle. For larger aerial ropeways, the required "free height" is at least ten meters. Mining authorities stipulate a free height of at least three meters for smaller cable cars . The calculation of the bumpers is based on DIN 4118, headframes and headframes for mining; Load assumptions, calculation and design bases . In addition, the steel construction adaptation guideline must be taken into account when dimensioning the bumpers . However, the bumpers are not elastic, so that the conveyor cage is suddenly braked in the event of an impact. In order to reduce the force of the impact, so-called baffle blocks are attached to the underside of the impact beam as an energy-consuming device. These woods must have a minimum thickness of 20 centimeters. It may be necessary that the bumpers must also be reinforced towards the top in order to be able to stop the conveyor vessel or the conveyor cage safely by the baffle.

Effects

An impact on the bumper beam can damage the conveyor cage. The force of the impact on the bumpers can even be so strong that the rope breaks . This harbors considerable dangers for the traveling miners . So that the cage does not fall into the shaft in the event of a cable break, several safety supports are attached below the impact beams .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Technical requirements for shaft and inclined conveyor systems (TAS). Verlag Hermann Bellmann, Dortmund 2005
↑ ^a ^b Hans Bansen (Ed.): The mining machines. Fourth volume, The shaft production. Published by Julius Springer, Berlin 1913
↑ Entire legal regulation for mountain police regulations for the cable car, in the version of May 18, 2011 online (accessed on January 13, 2012)
^ ^A ^b ^c ^d ^e Carl Hellmut Fritzsche: Textbook of mining science. First volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1961
↑ ^a ^b Patent No. 73616 Excessive protection for shaft conveyance. Online (accessed January 13, 2012; PDF; 225 kB)
↑ ^a ^b Andreas Hachmann: The renovation of a headframe from 1944 (steel construction). In: Hossein H. Tudeshi (Ed.) AMS Online GmbH: Advanced Mining Solutions. 2014, No. 3, pp. 6-17
↑ ^a ^b Horst Roschlau, Wolfram Heintze: Bergmaschinentechnik. VEB German publishing house for basic industry, Leipzig 1977

Remarks

↑ The free height is the distance between the conveyor cage, in its highest operating position, and the bumper beam. (Source: Carl Hellmut Fritzsche: Textbook of Mining Studies. First Volume)

[Quelle_1-1] ↑ ^a ^b ^c ^d ^e ^f ^g Technical requirements for shaft and inclined conveyor systems (TAS). Verlag Hermann Bellmann, Dortmund 2005

[Quelle_6-2] Hans Bansen (Ed.): The mining machines. Fourth volume, The shaft production. Published by Julius Springer, Berlin 1913

[Quelle_4-3] Entire legal regulation for mountain police regulations for the cable car, in the version of May 18, 2011 online (accessed on January 13, 2012)

[Quelle_2-4] A ^b ^c ^d ^e Carl Hellmut Fritzsche: Textbook of mining science. First volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1961

[Quelle_3-5] Patent No. 73616 Excessive protection for shaft conveyance. Online (accessed January 13, 2012; PDF; 225 kB)

[Quelle_7-6] Andreas Hachmann: The renovation of a headframe from 1944 (steel construction). In: Hossein H. Tudeshi (Ed.) AMS Online GmbH: Advanced Mining Solutions. 2014, No. 3, pp. 6-17

[Quelle_5-7] Horst Roschlau, Wolfram Heintze: Bergmaschinentechnik. VEB German publishing house for basic industry, Leipzig 1977

[Anm._Fritsche-8] The free height is the distance between the conveyor cage, in its highest operating position, and the bumper beam. (Source: Carl Hellmut Fritzsche: Textbook of Mining Studies. First Volume)