for the life of me understand how it was meant to work.
The engine is a single cylinder steam engine with the steam chest on top of
the cylinder. Instead of the usual single slide valve arrangement (a la
Stuart Victoria), it has two rods driven from individual eccentrics, but
the eccentrics throw is aligned ie there is no angular difference in the
throw of the eccentric. Through an arrangement of levers two rods for
operating the valve gear emerge one vertically above the other. At this
point the timing of the action has moved from being in phase to being in
anti-phase. The lower rod drives what appears to be a conventional slide
valve covering three ports, though its difficult to be absolutely sure
without stripping this down (I can't get at the underside of the valve).
The upper pushrod is connected to nothing in the steam chest, whatever
valve it was supposed to drive is long gone. There is too many hours work
in the model for all that assembly to be a dummy (assumption).
I've drawn a complete blank as to how this valve gear was intended to work
or what the missing valve looked like - hours of fruitless Googling has
revealed nothing like this.
So I've tried to sketch the valve chest side on
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And provided this photo of the valve gear arrangement:
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Any ideas gratefully received -
TIA
Steve