Unformatted text preview: full face has been cut, the machine is moved forward.
10.2.1.2 Disc type In this type of ripper unit, there are two cutting heads, each consisting of two vertical
discs laced with tipped bits. The cutting heads are carried in the front end of an extension boom. In this machine the cutting heads are rotated and at the same time a
to-and-fro movement of about 25 times/minute is imparted to the gear case and the
cutting heads. The resulting motion, therefore, of each pick is spiral which results in
low consumption of power and less degradation of rock/coal. In one of the designs, for
example, the cutting head cuts a kerf of 2.5 m wide and 0.6 m deep. The discs rotate at
the speed of 75 r.p.m. The cutting head can be lowered or raised hydraulically. Apart
from the cutting head, the machine has got an apron with gathering arms, a conveyor
extending up to the rear of the machine and crawler tracks. These types of machines can
be operated for the coal seams having thickness range 1–3 m.
Different combinations of ripper type boom headers with different muck loading
units include backhoe excavator loading the muck into trucks; cutter boom dischar
ging muck on to a chain conveyor unit for its onward transportation into trucks and the
integral unit gathering arms of a ripper-heading machin...
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- Spring '14
- Francis Group, Taylor & Francis Group, Excavator, roadheaders