Willis Floating Lever action to Couplers

For a full resolution view of the Willis Floating Lever - click on the picture above

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.