Willis Floating Lever action to Couplers
For a full resolution view of the Willis Floating Lever - click on the
The beauty of the Willis Floating Lever Action is the way in which the
movement of the motor tracks the movement of the key and therefore the
pallet, acting only to reduce the weight of any coupled action to the manual
which includes the lever, without interrupting in any way the direct linkage
between key and pallet.
As a means of clarifying the description of the motion of the floating
lever, consider the wind to be "off". At the depression of the key, the
lever M is pulled downwards by the tracker C - the fulcrum will then be
at T, the lever moving about that point. This is a temporary fulcrum
The valve H will then be open. A space is produced between the lever
and the plunger at F: with the wind "on" the wind passes into the chamber
J and thence by the valve H into the motor S; It will try to escape through
the valve D by raising the valve with its own pressure, but the downward
pressure of wind on the valve E equals the upward thrust on D and thus
no escape is possible.
As the wind inflates the motor S, the lever is pulled up at the end
marked T - the fulcrum has now changed to the opposite end and the lever
swings upward about the centre W raising the valve H, this continues until
this valve closes altogether, the wind being cut off from the motor S.
The motor remains inflated and open because there is no escape at any point
(even if the motor is leaking, wind will be re-supplied automatically by
valve H). All this happens more quickly than the eye can follow.
With the motor open and the key end of the lever down, valve H is closed,
therefore an imaginary point Z on the lever between point F & G has
restored itself to the same relative position as when the action was at
rest - both the supply and the exhaust valves are closed, yet the motor
is open and the key down.
As the finger is released from the key, the imaginary centre at Z will
move upward as the key tracker C is released by the finger - once more
the fulcrum has returned to the opposite end of the lever. The double valve
D E is now opened so that the motor S collapses and the lever falls at
T - the fulcrum has changed again back to W and thus the double valve D
E falls shut and closes the exhaust valves.
This action is almost silent in operation.
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