Mining truck

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A trolley is a track-bound conveying means in mining underground to feed fluid, mineral or mountains is used. Trams are mainly used in main lines , in connection with locomotives , for rail-bound commuting.

Basics and history

The first trams were used in the mining industry in the second half of the 19th century to transport routes . Although they differed significantly from the hunt in structure , they were often referred to as hunt. The difference between the classic Hunt and the more modern trolley lies essentially in the design of the rear wheels. These are larger than the front wheels on the Hunt and the same size on the truck. Even at that time, the trolleys had a larger capacity and were therefore used wherever large masses were to be conveyed at higher speeds. This was mainly the case in lignite and hard coal mining . But also for the extraction of noble ores mine wagons were gradually used more and more and displaced the hunt that had been used until then. The trolleys were pushed by young miners from the mining operating points to the main lines and from there they were transported to the filling site by pit horses or by means of ropes . In the first half of the 20th century, people began to develop and use cars with a larger capacity. This trend continued in the second half of the 20th century. The usable volume of these trams has been increased in stages from one cubic meter to seven cubic meters. Self- emptying conveyor wagons such as the Granby wagon or the floor dump truck were also increasingly used to convey bulk goods.

construction

Basically, a trolley consists of the three main components car body, frame and wheelset. There are also connecting elements such as the coupling and shock-absorbing components such as the buffer.

Car body

The cross-sectional shape, the material used, the capacity and its dimensions (length, width, height) are decisive for the construction of the car body.

There are different cross-sectional shapes for the car body. Depending on the cross-sectional shape, a distinction is made between trough cars, boxes with a rectangular cross-section, boxes with a trapezoidal cross-section, boxes with broken side walls, boxes with curved side walls and trolleys with crooked boxes. Of all types of wagons, the wagon with a trough-shaped cross-section is the most common. This is primarily due to the fact that this type of cart is the most resistant due to its cross-sectional shape. This car body also has the fewest corners and therefore the fewest weak points. The car body with curved side walls has the largest capacity of all shapes. However, the long sides of this box dent slightly and break through quickly when filling. A sediment made of fine coal and mountains quickly collects in the box. The rectangular box has the smallest capacity of all cross-sectional shapes and too high a center of gravity . In the case of the trapezoidal and broken side walls of the car body, the wheels are not sufficiently protected under the car so that they can easily become soiled by dust falling out of the body.

Either wood or sheet steel are used as materials for the car body. These materials are either used individually or together. The side walls of wooden boxes are made of planks with a thickness of 25 to 35 millimeters. Wooden boxes are cheaper to manufacture, but they wear out much faster than boxes made of sheet steel. In particular, the bottom of the box is heavily used. This is particularly noticeable in the mining of ores or mountains. The bottom of the box is therefore made of much thicker wicker or oak planks with a thickness of at least 40 millimeters. These are then placed across to achieve greater resistance. Boxes with a double bottom are even better. However, such car bodies can easily be repaired by replacing the worn planks with new ones. Another disadvantage of this box is that the wood soaks up moisture and then increases in weight. In the case of car bodies made of steel, the side walls are made from individual sheets, which are then either riveted or welded together. The sheet steel is protected against rust by hot-dip galvanizing . For boxes made of mixed materials, the box floor is made of five millimeter thick sheet steel. The side walls are made from 33 millimeter thick fir planks. Due to their robustness, only trolleys made of sheet steel are used today.

The selected box capacity depends on various factors. First and foremost, the dimensions of the routes are decisive for the use of a car size. The track width of the underground rail network also has an influence on which wagon size is used. While at first only trolleys with a capacity of 750, 875 or 1000 liters were used, since the 20th century mainly boxes with a capacity of 1250, 1500 or 2000 liters have been used. The dimensions of the box are essentially influenced by the dimensions of the shaft and the cross-sections of the route. If you want to increase the capacity of a car in existing systems, this can best be achieved by increasing the height.

Frame

The frame, also known as the underframe, is used to connect the car body and the wheelsets. The frame is made of either iron or wood. Profile iron is used for frames made of iron. Double T-beams or sometimes U-irons are used here. Wooden bases are made from planks that are screwed together. The disadvantage is that the center of gravity of the trolley is shifted significantly upwards by the frame. Another disadvantage is that the frame increases the height of the trolley. This makes it more difficult to fill the box and reduces the capacity.

Wheelsets

The combination of axle and wheel and the associated connecting pieces are referred to as wheelset, half-wheel set, or track. The wheel sets are either attached to the underframe or directly to the box floor. When determining the attachment points for the wheel sets, two dimensions are of great importance, the wheelbase and the track width. The wheelbase must be kept within certain limits. This is necessary to prevent the car from rocking. The wheelbase depends on the length of the car body. It is between 400 and 600 millimeters for smaller trucks and between 1200 and 1700 millimeters for larger trucks. It should be noted that with larger wheelbases, the radius of curves must also be larger. The gauges are adapted to the respective track network. They are usually 600 or 750 millimeters. There are also mines where the underground rail network has a gauge of 1000 millimeters. The track widths must be adapted to the width of the wagon within certain limits, but they must not exceed a certain amount so that the areas of track bends can be passed through more easily. In addition to these standardized track gauges, there are also mines in which the tracks are laid with dimensions in between. The wheel sets can be designed in such a way that the wheels are either firmly bolted to the axle or connected to the axle by means of bearings . Thus, either the axles turn in their bearings or the wheels turn in their wheel bearings. If the axle and not the wheels are mounted, the wheels cannot turn independently of one another. As a result, the outer wheel is braked by the inner wheel when cornering. This then inevitably leads to greater wear. Tapered roller bearings are used as bearings for the wheel sets. In order to avoid increased wear on the bearings, they must be provided with suitable lubricants at regular intervals .

coupling

The buffer can be seen at the front of the car, the coupling is located under the buffer.

To connect the individual trolleys to one another, each trolley is provided with a coupling. The coupling consists of two iron rings and an associated hook. The rings are mounted in the middle of the carriage. When coupling, the hook is hooked into one of the rings. The coupling must be designed in such a way that it does not sag when the trolleys are pushed together and thus bump into or get stuck on the lying surface . In cornering areas, the coupling must be able to give in a little to prevent the car from being levered out. In addition, the coupling must not protrude beyond the end walls of the trolley when it is hanging down. The clutch might otherwise in the well production in the shaft at the Einstein Richen stuck. In addition to these simple hand clutches, there are also trolleys that are equipped with an automatic clutch.

buffer

Each trolley must be equipped with a buffer at each end of the car. These buffers are intended to absorb the strong impacts that occur during the conveying operation. In the wooden trolley cars, the long trees that are lengthened over the car body are shod with sheet iron and wrapped around with rings. In the case of steel trolleys, the buffers are also made of steel. The buffers must be dimensioned in such a way that the car bodies do not hit each other when driving through curves. The buffers must each protrude at least 100 millimeters above the edge of the car. The buffers are either rigidly connected to the trolley or are sprung. Only special friction springs are used as buffer springs. There are also special block buffers that are equipped with a movable pull rod. The tensile forces are transferred from the tie rod to the buffer springs via a counter bearing. The tension springs can absorb both the tensile and impact forces.

Classification according to car size

Depending on their capacity, trams are divided into small, medium and large conveyors. Which wagon size is used depends on the cross-section of the route, the size of the conveyor frame and the curve radii of the track network.

Small truck in front of the Feggendorfer tunnel

Small trucks

Small conveyors are conveyors with a capacity of up to 1000 liters. In this type of car, the car body consists of five millimeter thick, hot-dip galvanized sheets that are welded together. Despite the 40 percent lower weight, aluminum trolleys were not used. This was because these wagons were not sufficiently resistant to aggressive mine water . They were also about eight times as expensive as carriages made of sheet steel. Rigid wheel sets are used as wheel sets in this type of car. The buffer of this type of car is unsprung and made of cast steel or forged steel.

Medium trolley

medium trams at the conveyor belt on Zollern

Medium conveyors are conveyors with a capacity of up to 2.5 cubic meters. Medium-sized trucks are similar in structure to small trucks. Two different wheel sets are often used as the wheel sets. One then uses a fixed and a pendulum wheel set. As a rule, middle conveyor vehicles are equipped with a spring-loaded buffer.

Large conveyors

Large conveyors, or large-capacity conveyors, are conveyors with a capacity of more than 2.5 cubic meters. With this type of wagon, a distinction is made between long wagons and wide wagons. Long conveyor vehicles are predominantly used in the German hard coal mining industry. The long shape means that the shaft cross-section is used more efficiently . In addition, when using long wagons, it is possible to convey two wagons side by side in the same shaft disc . On lines with a smaller cross-section and with double-track conveyance, the long wagon has less of an impact on the profile freedom than the wide wagon. The wide wagon is mainly used in North American mining. This is due to the fact that in North American mining mainly low but wide stretches are driven . Wide cars also have better cornering behavior than long cars.

Special car

Medium, Granby and large conveyor vehicles
Front tipper

In addition to the normal trams, there are also various special types of trams. There are special tipping wagons that are used to extract ore. At the shaft, the contents of the wagon are then poured into shaft bins. Depending on whether the goods to be conveyed are thrown out of the wagon from the short or the long side, the wagon is then referred to as a falling wagon or a tipping wagon. Depending on the material, there are stake wagons , silo wagons, pallet wagons or containers for material transport. Stake wagons are used to convey long materials. Silo wagons are used to convey liquids or powdery material. Flat wagons are used to convey large piece goods. Containers are used to convey small piece goods. There are also special wagons with a larger capacity that empty themselves. These types of cars, such as B. the Granby wagon or the bottom dump truck are used to promote ores, coal or salt.

Individual evidence

  1. ^ Tilo Cramm, Joachim Huske: Miners' language in the Ruhr area. 5th revised and redesigned edition, Regio-Verlag, Werne 2002, ISBN 3-929158-14-0 .
  2. ^ A b Ernst-Ulrich Reuther: Introduction to mining. 1st edition, Verlag Glückauf GmbH, Essen, 1982, ISBN 3-7739-0390-1 , pp. 38-39.
  3. ↑ a b c d e f Albert Serlo: Guide to mining science. Second volume, 4th revised edition, published by Julius Springer, Berlin 1884, pp. 9–47.
  4. ↑ Commission of the European Communities (ed.): Conveyor technology in hard coal mining underground. Volume 1, Verlag Glückauf GmbH, Essen 1978, ISBN 3-7739-0233-6 , p. 10.
  5. ^ Hermann Schäfer: Development possibilities for large conveyor vehicles. In: Glückauf, Berg- und Hüttenmännische magazine. Association for mining interests in the Oberbergamtsiertel Dortmund (Ed.), No. 7, 77th year, February 15, 1941, pp. 105–109.
  6. ↑ a b Heinrich Otto Buja: Engineering manual mining technology, deposits and extraction technology. 1st edition, Beuth Verlag GmbH Berlin-Vienna-Zurich, Berlin 2013, ISBN 978-3-410-22618-5 , pp. 349-350.
  7. ^ Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 , pp. 545-546.
  8. ↑ a b c d e f g h i j k l m Fritz Heise, Fritz Herbst: Textbook of mining studies with special consideration of hard coal mining. Second volume, fifth increased and improved edition, published by Julius Springer, Berlin 1932, pp. 398–415.
  9. ↑ a b c d B. W. Boki, Gregor Panschin: Bergbaukunde. Kulturfond der DDR (Ed.), Verlag Technik Berlin, Berlin 1952, pp. 511-520.
  10. ↑ a b c d e f g h i j k Hans Bansen (Ed.): The mining machines. Sixth Volume, The Line Funding. Published by Julius Springer, Berlin 1921, pp. 30–57.
  11. ↑ a b c d e f g h i j k l m n o Carl Hellmut Fritzsche: Textbook of mining science. First volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1961, pp. 342, 355–367.
  12. ↑ a b c d E. Glebe: Investigations into the use of large conveyor vehicles in Ruhr coal mining. In: Glückauf, Berg- und Hüttenmännische magazine. Association for Mining Interests in the Upper Mining District Dortmund (Ed.), No. 45, 73rd year, November 6, 1937, pp. 1009-1017.
  13. ↑ Horst Roschlau, Wolfram Heintze: Bergmaschinentechnik. VEB German publishing house for basic industry, Leipzig 1977, pp. 245–246.
  14. ↑ a b c d e f Horst Roschlau, Wolfram Heinze, SDAG Wismut (Hrsg.): Knowledge storage mining technology. 1st edition. German publishing house for basic industry, Leipzig 1974, pp. 173–174.
  15. ^ A b c Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary. 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .