Roadheader

A roadheader (TSM ) is a tunneling machine for tunneling and mining. Roadheader are due to their design to the peripheral milling. As today's roadheader work with cutting heads, called these machines cutting head machines. With roadheader arbitrarily shaped track sections can be created.

• 4.1 force entry into the rock
• 4.2 Dust Control

History

The first roadheader was used in the mid-1960s in Eastern Europe. This machine consisted of a frame with the tracked undercarriage of a working tank. A cantilever arm on the base frame was attached to the upper end of cutter heads were mounted. The boom had a three-axis motion. These machines were also used in Western European coal mines for testing. In the early 1970s they began in Western Europe in order to develop their own machines. First, originating from Eastern Europe machines were rebuilt and improved in the license, and later own machines were constructed. The roadheader were developed in parallel with the full -face machines.

Construction

The roadheader consists of a base frame ( machine body ), which houses the hydraulics of the machine. At the front of the machine an arm is mounted. The boom is both horizontally and vertically pivotable. At the upper end of the boom is the cutting head. The cutting head is equipped with several cutting chisels. The TSM is equipped for locomotion with two caterpillar tracks. Some TSM types have border plants instead of the crawler tracks for locomotion. The operator usually sits as an excavator on the machine, the operator can place on small machines or with low cross sections but also behind or beside the machine be arranged. For Wegladen of the bulk material is located on the front of the base frame in the sole area a loading table, which is equipped with an appropriate charger. For conveying away the bulk material, a scraper chain conveyor is integrated in the center of the machine chassis or to the side. This scraper chain conveyor is dimensioned so large that larger rocks can be conveyed away. The entire conveyor is adjustable in height usually and swivel. Thus at brächigem hanging wall immediately after cutting a First backup in the form of anchors or Gebirgsverfestigern can be introduced, roadheader if required be fitted with a drilling. The power supply of the machine is integrated with larger roadheader in a Nachläuferzug. In this Nachläuferzug is also the dedusting and all other resources such as the weather climate.

Machine types

Roadheader be divided into axially and radially in overlapping types. Axial cutting part cutting machines have a cross- cutting head. In these machines, the cutting head axis is perpendicular to the boom. Due to the design work on this machine, the reaction forces in the direction of cutting arm. For this reason, axial cutting machine types have a relatively low weight. Radial cutting part cutting machines have a longitudinal cutting head. In these machines, the cutting roller rotates in the extension of the cutter. For this reason, the reaction forces are applied vertically to the cutter. Due to the long lever arm, the weight of the cutting head has an effect on the required weight of the machine. Machines with radial head be cut require a high weight. The weight of the machine must be so high that it can counteract the overturning moment during pivoting of the cutting head.

Sizes

According to the requirements roadheader be built with different driving powers for the cutting head and varying total weight. Currently, there are machines with power ratings from 20 kW to 400 kW and total weights of 8 tons to 140 tons. Depending on the driving power and the total weight machines are categorized from mild to extra heavy or over hard.

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Operation

To edit the working face, the roadheader is to run with the crawlers on the working face and the cutting head is set in motion. Subsequently, the working face of the tunnel and the track is piecewise milled with the cutter head. In order to fully edit the working face, first a so-called break-in of the face must be created. After the break-in was created, then the entire working face can be milled. The material is cut out feinstückig by the cutting head. The removed by the tipped with tungsten carbide tools milling head material or rock is taken with a loading shovel and pushed by several loading arms or the rotating loading disks to a centrally running through the roadheader scraper chain conveyor. At the end of the conveyor belt, the rock is then dropped on a boom on a conveyor belt that needs to be tracked progresses Drift excavation.

Force entry into the rock

In the roadheader the power entry is made into the rock in two ways. On the one hand by the rotational movement of the cutting head, the other by the pressure against the rock. The proof printing inducing to the mountains feed force is provided by the crawlers. The machines can not be clamped to the mountains, for this reason, the inclusion of the restoring forces takes place during the cutting process by the machine ground. So that the machine can initiate a high enough force into the rock, she must have a high mass. The greater the weight of the machine is, the more solid rock types can be cut with the machine.

Dust control

When milling the rock produces a lot of dust, which must be fought by appropriate means. There are two ways that dust extraction and sprinkling with additional ventilation. In the Dust of the dust is concentrated extracted at the point of origin and directed to a dust. For suction, there are two possibilities, the extraction of a anticipatory pilot tunnel or extraction via suction pipes. The suction pipes are mounted on the machine left and right. The suction pipes flexible air tubes are fixed on the dust is then guided to the dust removal system. When sprinkling the dust is wetted by water sprayed and thereby partially bound. The water is sprayed through special inner nozzles are integrated in the cutting head under high water pressure. The water pressure is adjustable within limits. This is necessary to equalize the amount of water required to the local conditions. The water cools at the same time the cutting bit and reduces the sparks when cutting. In addition, the remaining dust is extracted and sent to dedusting.

Applicability and limitations

Roadheader can be used for excavation in rocks of medium strength. Particularly in the case of layered and fractured rock roadheader are well suited. You can with a roadheader mount up different route profiles. The operating limits of roadheader lie primarily in the compressive strength of rock. However, these limits are not fixed but are influenced by many factors such as particle binding, tensile strength, joint faces and rock classification. Key factors are the stability of the cutting tools and the drive power and the total weight of the machine. Another limit to the applicability of roadheader is the track cross section. With too little roadway cross -sections roadheader can not be used because such small machines can not provide the required cutting power.