DESIGN OF A LABORATORY STAND FOR THE TESTING OF MECHANICAL CUTTING OF COAL AND ROCKS

ABSTRACT

The establishment of the characteristics to mechanical cutting of the rocks through chipping, just as it happens in practice for the bucket-wheel excavator having teeth, represents an elemental problem and underlies the concrete knowledge of rocks dislocation.
Interdependency laws among the geometric parameters and technological ones of the chipping teeth, the parameters of the dislocated chippings and the parameters of the cutting regimes which can be established taking into account qualitative and quantitative aspects for each rock respectively have to be based on data obtained through experimental attempts.
The stand for cutting non-homogeneous materials used for the determination of specific resistances to cutting of the lignite and sterile material is composed of hydraulic machine, model 7310 D, a tensometric dynamometer used for measuring the stresses in the tooth, the standard tooth set, sample of lignite or rock, the equipment for recording and processing experimental data and the electrical power and control system for the stand supply and command system. The stand ensures the attainment of the cut-off force with values in the aisle 5,000…28,000 N, cut-off speed contained between 0.05 and 0.8 m/s and a cutting length of 1,000 mm. Also the standard set of teeth permits a variable angle of chipping removal between 10 and 50° and the simulation of teeth wear. The workbench of the hydraulic machine permits the use samples having the maximum sizes of 600×500×400 mm.

Keywords: testing stand, mechanical cutting characteristics, bucket-wheel excavator