HOISTING TECHNOLOGY
platform, on which the control cabin with switch
cabinet, the boom, the drum winder and the drive
components required for the boom and winder
movements are mounted, is connected with the
base frame via a double-row slewing ring.
Depending on the shaft conditions, operation
can be performed independently of external
energy supply via a generator powered by the
truck’s diesel motor or via an external power
supply provided by the respective mine. These
two drive variants are a safeguard against power
failure.
The company told IM: “Compared to
conventional mobile shaft winches, which have an
emergency power supply via an additional standard
diesel generator set, OLKO’s patented system, with
the supply via a generator has on the one hand, the
advantage of a lower noise level and, on the other
hand, a significantly lower exhaust gas development
due to the truck engine, which is approved according
to Euro 6 emission class.”
Another development patented by OLKO
consists of a permanent monitoring of the hook
load. The existing hook load is permanently
acquired by a load measuring pin in the rope
attachment. The load measuring pin is arranged
in the round rope thimble of the rope attachment.
The signals are transmitted via two of the eight
wires inside the hoisting rope. Load steps due to
touchdown (slack rope) or jamming of the
kibble/hoisting installation result in immediate
shut-down of the winder. This measurement is
performed independently of the boom working
position or rope pulley and rope length. The
current load is continuously displayed via a
monitor in the operator’s cabin.
It is also possible to use existing
kibbles/cages that are additionally equipped
with a float/touch down switch on the bottom. If
the kibble actually touches/floats down, the load
measuring pin line is interrupted by the switch,
resulting in immediate shutdown of the winder.
In this case, the machine operator can only move
upwards, identically to slack rope functions. The
lower frame is equipped with an additional
hydraulic unit used for the operation of the
lateral supports. The respective valves are
operated manually. As with the generator, the
associated pump is powered as an auxilliary
drive via the truck’s diesel motor. The telescopic
boom can be loaded with a 5 t hook load in every
position. During hoisting inside the shaft it is
possible to carry out all crane movements (tilting,
telescoping and rotating) within the shaft with
persons in the kibbles/cages. All of these
movements, necessary for hoisting or
inspections, are recorded redundantly and
monitored in the machine control. “We are sure
that we have developed an innovative system
which will offer several benefits to our customers
compared to existing systems.”, says Uwe
Koesterke, Head of Engineering.
Hoist brakes for Elko
Twiflex, a member of the Altra Industrial Motion
Group, a leading global supplier of power
transmission components, late last year provided
a parking and emergency brake for use on hoists
at a gold mine in Elko County, Nevada. The VCSD-
VR brakes are installed on a motor pinion,
operating on a 1.168 m diameter disc to produce
a total torque of 128 kNm.
The Twiflex VCSD-VR is a spring-applied,
hydraulically-released disc brake which has been
designed for use in harsh environments, while
providing superior performance in heavy duty
dynamic and emergency stopping applications.
According to Steve Powell, Product Manager
for Twiflex, when selecting brakes for mine
hoists, it is important to consider factors such as
the depth of the shaft, stopping profile, drum
design and payload in order to calculate the
braking torque required for each application.
For mine hoists, Twiflex typically aims to
provide a braking solution which offers over two
million braking cycles to meet exacting industry
requirements. Twiflex’s VMS brake range for
hoists produces up to 460 kN braking force at a
nominal 0.4 coefficient of friction and 2 mm air
gap (distance between pad and disc face).
In the Elko gold mine application, the braking
speed is low at 500 rpm, but the stopping time
required is between 3 and 5 seconds, meaning
that the peak disc temperature and power