PART TWO - Introducing Patent 25964 of 1957A reading of the patent shows that Villager had read and understood the
Champion patent (linked below). Villager increased the cooling power by
incorporating
blade holder design in the equation.
If flywheel fins could circulate air across the ribbed cylinder cooling fins,
then that convection could be improved by the use of a
fanned blade holder,
acting through an
orifice in the mower base.
The 'Twin-Cooling' referred to the radiation of heat from ribbed cylinders,
and the convection currents produced by the rubber fins in the flywheel
'cake tin' cover and the blade holder. As to how efficient it was - over
close shrouded engines - I have no idea - but it would have been less
efficient. Maybe this was all about marketing ...
The patent, lodged in
March of 1957, is fairly east reading. But a few
things are worthy of note. The first, as an aside, is that Villager was
an early propagator of
swing-back blades.
The second point is that the
rubber vanes in the 'cake tin' flywheel cover
are sparse. The third point is that Figure 5 in the illustration depicts
metalware that purports to direct hot air through aperture [17] that is,
through the chassis base.
For me, the real interest is in the
blade holder. This is an early example
of the emerging sophistication of air flow in blade holder designs.
The
Twin Cooling system had
four components [see Photo Record].
TO BE CONTINUED ...