Vol.12, No2, 2012, pp. 87–92
UDC 620.17:621.879.4

The chain excavator is the main technological part of a cleaning machine which is used for technological operation of railway maintenance. The purposes of the sub-assembly are to excavate the crushed stone (ballast) from the railway, under the sleeper and to transport it to the screen, where it is cleaned, sorted and reused. The chain excavator is loaded in bending, abrasive wear, shock, tension and other stresses. Due to these stresses, the chain excavator has defects as fractures, fatigue, wear and other. These defects can lead to a dangerous malfunction, defects, or immobilizations of the cleaning machine with risks for safety work and important losses of productivity and value. In this paper we establish and present the stress system, wear zones and some defects and fractures of elements of the chain excavator. Another important novelty is the FEM analysis using CAD for some extreme stress cases and the comparison of this analysis with experimental conclusions in situ. Effects of some types of usual defects are also analysed.

Keywords: chain excavator, cleaning railway machine, stresses, fracture and fatigue, wear, FEM, CAD