Conical picks of mining machines with increased utility properties – selected construction and technological aspects

mineral deposits, especially hard coal, and for drilling roadways in
underground mines, tunnels and other underground buildings in civil
engineering. As the primary working process of this type of
machines, mechanical mining of rocks is carried out by cutting.
These machines' working units are equipped for this purpose with
picks, usually conical (point-attack). They have the form of an axially
symmetrical body consisting of a steel shaft and a tip usually made
of tungsten carbide, connected by a hard brass solder. Due to the
possibility of spontaneous rotation in the pick holders and even wear
and tear of their tip around the entire perimeter, conical picks have a
much longer service life compared to radial picks. Their life,
especially when cutting hard and sharp abrasive rocks, is, however,
still unsatisfactory. Rapid wear of the picks leads to a decrease in
mining efficiency, an increase in this process's energy consumption,
and an increase in dynamic surplus to which the cutting machine is
subject. Among many forms of wear and tear of the conical picks,
attention was paid to the problem of asymmetrical abrasive wear of
the tips, pulling out the connection of the soldered pick tip and fatigue
breaking of the pick shafts in the transition zone of the shank into the
shoulder. The article presents original propositions of modification
of the construction of the roadheaders/shearers conical pick shafts
and the method of fixing the tip in the pick shaft in order to increase
their operational durability significantly. The technologies and
devices necessary to manufacture conical picks of the proposed
structure were described. The developed modifications significantly
contribute to the improvement of functional properties, including the
reliability of conical picks, used in particular for hard rock mining.