Design of the roof support with strait-line mechanism

One of the most important aspects of machine designing is to balance between the economic requirements and the safety ones. Taking into account these requirements it was conducted the design work to elaborate the new concept of the mining roof support that fulfil them. The mining roof support is a mining equipment that has the most influence on the safety of work in deep coal mines and on the productivity of deep mines. Moreover the hydraulic roof support generally accounts for over 50% of the total value of a coal mining and excavating system. It is considered not only with the complexity of the roof support but also with the accepted direction of the development of mining supports. Generally designers elaborate heavier constructions with props of larger diameters and loads. In this way the support system must be prepared not only to withdraw the rock mass forces but also the forces generated by its hydraulic system. These prerequisites underlie the new project of a roof support. This project bases also on many Polish patents concerning the mechanical devices and hydraulic equipment of a mining roof support. The main idea of the work was to elaborate the scheme of a support that will be compatible with the system of loads generated by the rock mass and by the conditions of work in a deep mine. As a result it was proposed the concept of a hydraulic roof support equipped with four props that work only in a vertical position. To realize that task it was proposed the special designed strait-line mechanism protected by Polish patent. This mechanism is supported by gas springs with low resistance. These springs allow eliminating horizontal forces which are generated by roof rocks. It has been also designed the special flexible roof part (also patented) that allows to eliminate the horizontal component of roof rock loads. The hydraulic system is equipped with gas dampers that compensate dynamic loads during bumps in longwalls. The design of the dampers is also patented. In the result of the design process the new concept of the roof support have been elaborated. One prototype has been manufactured. According to analysis it is about half the weight of standard roof support and the cost of it reaches the 50% of a standard one. It may be the optimal proposal for the European mining industry.