BMHR 2016
52 \
World Cement
several months the deck boards start to warp and
crack. Was the cost really a good value?
Solution
There are no shortcuts when it comes to quality
chain. If a deal seems too good to be true, it probably
is. High quality materials – free from imperfections
and impurities prevent failures. Cheaper materials
will reduce upfront cost, but can lead to major costs
sooner than you may realise. So when considering
your supplier, it’s vital to look into how long they
have been making chain, the integrity of their
materials and their track record.
Problem: side plate failure
Side plate fatigue failure is one of the most common
types of failure that occurs with elevator chain
systems. Poor pitch hole quality, or old designed
punched holes with flats, result in scarred holes
through the thickness of the side plates – creating
concentrated stress areas that can lead to side plate
fatigue failure. These fatigue failures usually
originate at a specific point and radiate through
the side plate, much like a fault line in an
earthquake zone. The result is side plate failure
and costly down time.
Solution
Specifying machined or burnished pitch holes
prevent problems with side plate failures. Not
only will this extremely precise manufacturing
process solve premature side plate fatigue
failure, the design allows for much tighter
tolerances. These more precise tolerances cannot
be achieved with the old traditional way of just
punching pitch holes. Machined or burnished
holes provide the maximum interference fit,
a press fit if you will, between the pins and
bushings. This results in higher fatigue strength
and provides a much longer service life for your
chain.
Problem: severe pin wear
Extreme load conditions, high bearing pressures,
and abrasive material in the joint area cause
excessive pin wear. In some cases, premature pin
wear can result in major chain failure. As the
pins and bushings wear, diametrical clearances
increase between the pin and bushing allowing
more abrasive material to enter the joint area
resulting in increased wear conditions.
Solution
Choose chain with induction hardened pins
that provide a deeper hardened surface area
for maximum wear resistance coupled with a
more ductile core. The end result is a chain with
increased strength, ductility, and maximum wear
ability for the maximum service life.
The final mix
This is just a snippet of the engineering and
manufacturing techniques involved with producing
high quality elevator chain that meets or exceeds
the requirements in the concrete industry. So
remember, getting a great price on elevator chain
can seem like a great idea at first, but a poorly
constructed chain can end-up costing the company
more in replacements and lost production time
down the road. So take the time to fully investigate
your options, because all chains are not created
equal even though they may appear similar. Make
sure that you are purchasing an elevator chain
that has been manufactured to the highest quality
standards, using ASTM standard steel and precision
manufacturing techniques. This will save a lot of
money and headaches in the future, while lowering
the overall cost of production through increased
service life.
Premature pin wear caused by abrasion.
This side plate failure was caused by poor quality materials.
