The popular clock on Broadgate House in Coventry, from which emerges,
on the hour, a 50 year old, life size wooden model of Lady Godiva, is now
up and running again, following a short period of disrepair. The
restoration included the installation of modern motor controls and PLC
systems, but the all-important drive relies on a rather special
transmission chain
Lady Godiva's legendary ride through Coventry market place has been
commemorated since the 1950s by a clock and a life size model that
emerges from Broadgate House in the city centre. While the clock, which
dates from the 1850s, needed no maintenance, the mechanisms associated
with Lady Godiva's hourly appearance finally failed after 50 years of
service and she stopped appearing. Coventry City Council decided that it
was high time for an overhaul and awarded the contract to restore the
mechanism to the clock repair company, Smiths of Derby, which specialises
in the overhaul and restoration of large outdoor and ornamental clocks.
Smiths project manager, Kevin Litchfield said his company actually made
the most expensive bid for this project, but he believed its focus on
quality and thorough engineering won through.
Lady Godiva is now driven by a new motor, new control gear and
all-weather Tsubaki PC chain running on nylon sprockets. Mr Litchfield
said that Smiths often used Tsubaki PC chain, because the combination of
engineering plastics and stainless steel enabled it to be run without
lubrication in exposed environments. In his experience, the chain
operates reliably for long periods without maintenance.
The horse and rider are carved from solid pieces of wood and weigh more
than 120kg, so the chain also had to have reasonable strength in order to
handle the inertia and cope with frequent use without excessive wear. New
stainless steel rails, a PLC based control system and a new door opening
mechanism - also driven by Tsubaki chain - have been fitted to ensure
timely appearances on the hour. Instead of speeding round as she used to,
Lady Godiva now takes a less hurried trip and stops in the middle of her
journey to give tourists a chance to photograph her.
Tsubaki PC Plastic Engineered Chain uses stainless steel side plates and
pins for corrosion protection and strength, but is lighter than standard
chain thanks to the use of tough engineering plastics in the construction
of the links and rollers. Resistant to the effects of weather, detergents
and steam, as well as food ingredients such as oils and lactic acid, PC
chain can be used in a wide variety of machinery that regularly needs to
cope with these types of environmental conditions.