Ibex has been designing and manufacturing shock cord and braided rope in
custom and standard assemblies for some years, its principal customers
being in the marine, construction, aerospace and leisure industries.
Recognising the potential for these products in a wider industrial
context, the company has now joined forces with Lee Spring to market a
new product called PowerSpring, which is based on the former's shock cord
technology.
PowerSpring is a high-strength tension/extension spring comprising a core
of many natural rubber filaments enclosed in a braided polyester fibre
tube. The cord is crimped at its ends to a metal fitting (which can be
supplied in aluminium, cold drawn steel or stainless steel). An epoxy is
then injected into the termination, which penetrates the spaces between
the filaments to form a solid plug. Finally, a metal disc is inserted to
cover and protect the bonded filaments. The integrity of this end
termination has been verified in tests carried out by the Institute of
Spring Technology, which saw a PowerSpring achieve in excess of five
million cycles.
A standard 32mm diameter PowerSpring delivers 3.5kN at 90% elongation
(maximum recommended), while the smallest 12.5mm diameter product
achieves 0.5kN. The service life of PowerSpring is considerably increased
when it is used in continually oscillating applications, where there are
a large number of cycles and the extension is not allowed to fall below
15% during load cycles. The rubber core resists most contaminants, apart
from mineral oils and ozone, from which it must be protected. For this
purpose, Ibex has developed a latex sealing coat, which is applied to the
outer braid.