Excerpted from Vertical Vanguards
By Paul Moore Editor, International Mining
The supply of hoists and winders, plus associated wire ropes,
brakes, electrical and automation systems is a specialized market with
a relatively small number of players. Paul Moore looks at some market
developments and new contracts.
As might be expected, technologies related to even greater safety
levels and maximum efficiency achievement though greater use of
digital tools dominate the world of hoisting and winders in mining.
Hoist brakes and controls, access shafts and hoisting systems
are essential components for mining activities. To optimize transport,
stopping and parking operations, these elevator machineries need high-
quality redundant controls for speed, acceleration and deceleration.
When a leading manufacturer of mine hoists, Coalfield Services,
Inc, needed a custom braking solution for one of its setups, it chose
Svendborg Brakes and Twiflex, two brands of Altra Industrial Motion
Corp, for the production of a reliable system. The mining industry
heavily depends on hoisting equipment for uninterrupted and efficient
operations. This offers vertical transport of miners and materials as
well as providing access to the network of openings used to recover
underground resources. Fundamental in key operations, mine shaft
elevators must be fully operational and accurate in their movements at
all times.
Twiflex Series VKSD spring-applied,
hydraulically released, dual-spring caliper
brakes act on a pair of discs shaft-mounted
to the hoist’s cable reel.
In particular, they should not be affected by power failures that
can occur at mining sites. More precisely, it is extremely important for
these systems to be able to maintain smooth and precise control to avoid
unexpected movements, such as abrupt stops and startups.
By showcasing these features, mine hoists can deliver comfort in
the transport of materials and workers as well as preventing the power
train from suffering shock loads caused by abrupt movements, which
can lead to substantial mechanical stress on multiple components. Only
advanced systems that can modulate braking forces and support ‘soft
transitions’ from movement to stillness and vice versa can guarantee this
level of performance in any condition.
When developing a highly reliable setup with these characteristics,
Coalfield Services, a major OEM of mine hoists, identified the most
suitable braking system as SOBO® (Soft Braking Option) iQ from
Svendborg Brakes, a leading global expert in intelligent braking
solutions. This solution is a closed-loop controller that can automatically
adjust the braking force, even in high-speed situations.
The industry-leading SOBO iQ braking
controller from Svendborg brakes, combines
cutting-edge technologies to provide
significant flexibility, safety and durability
on applications including mine hoists.
This ability is the result of three-state digital modulation, a dual-
loop proportional integral (PI) algorithm to control pressure and speed
and an internal pressure control loop. By combining these elements,
SOBO iQ can apply only the torque needed for a fully controlled
stop. More precisely, the system collects data on speed, pressure and
deceleration/acceleration from sensors on the brakes and compares
them to pre-defined setpoints. If the values differ, a suitable corrective,
modulated change is communicated to the brakes to adjust their action
accordingly.
In this application, the most suitable brakes to integrate with
SOBO iQ were identified as VKSD58 spring-applied, hydraulically
released caliper disc brakes from Twiflex, another brand within Altra
Industrial Motion. As a global leader in innovative braking solutions
designed to provide years of reliable performance, the company’s
solution is well equipped to withstand the challenging operating
conditions found in mines.
Furthermore, by relying on member companies within Altra, the
hoist producer could benefit from a one-stop-shop for its braking needs.
In particular, the two brands could leverage a strong, close collaboration
to deliver matching components for a fully integrated solution while
also offering a single point of contact to the hoist manufacturer.
Manufactured in-house, Svendborg Brakes’
specialized SOBO iQ hydraulic power units
are engineered to perform in tough mining
applications.
The spring applied calipers would assure operators that braking
would be maintained in the event of electrical supply system failure as
well as supplying sufficient braking force, as the VKSD series can reach
over 100 kN. In addition, to deliver a system that would fully address
the requirements of the mine hoist OEM, Twiflex leveraged its in-house
design and manufacturing capabilities to create the custom brakes.
The resulting solution consisted of SOBO iQ communicating with
VKSD58 calipers with proximity switches acting on a pair of discs
that were shaft-mounted to the hoist’s cable reels. For this project,
the elevator machinery manufacturer could benefit from advanced
application expertise from Svendborg Brakes and Twiflex, which proved
crucial to specify, integrate and customize the braking systems. Thanks
to the components provided, Coalfield Services improved the design of
its accurate, robust and reliable products, delivering enhanced setups to
clients in the mining sector.