Editing Marquardt Butterfly (section)

==Description==
A metal leaf spring with complex folds is placed down over the central terminal, onto which the return spring is also placed. The central portion of the leaf is cut through, and the cut ends sit in slot in the central terminal; the leaf by itself can then see-saw (vertically pivot), held entirely by the terminal. Grease is placed around the central terminal where the leaf fits into it. 

One end of the leaf is then fed through a slot in the slider, which raises and lowers that end of the leaf. To cause the snap action to occur, the opposite end of the leaf must be prevented from exceeding a particular height. With the switch opened, you can find this maximum height using an implement such as a screwdriver. If the leaf is pressed down too far, it remains in permanent contact with the second terminal, while if the leaf can rise far enough, it is not bowed enough to achieve snap action. A protrusion in the lid provides this ceiling point.

Through snap action, the free end of the leaf jumps towards and away from the secondary terminal, giving instantaneous make and break accompanied by a click sound as the leaf snaps between states. The bottom of the leaf spring is gold plated at one end, as is the top of the terminal. The click sound is quite loud, and is comparable to [[IBM]] [[Beam spring|Beam Springs]].

To reassemble the switch, the leaf spring must be pushed back down onto the centre terminal (which is quite fiddly) and the split ends fed into the slot into the terminal on each side. Once this is accomplished, it will see-saw smoothly on the terminal. Next, place the return spring onto the terminal, and insert the slider; the leaf should feed through into the slider readily, at which point the lid can be placed. Once the lid is pressed down, it may be necessary to give the switch a hard push to release the leaf spring into action.

The flat spring construction appears to function similarly to [[stacked spring]], giving the switch a distinct amount of hysteresis, somewhere in the region of 1 mm (something that is quite difficult to measure with callipers). Testing with a multimeter demonstrates that actuation occurs at the point that the click sound is generated, and the contact release occurs at the point that the hysteresis is cleared, where a second click is emitted. Unlike stacked spring, while the return spring sits on the leaf spring it does not appear to influence it.

The terminals are held in place by twist mounting: they are placed through rectangular holes, and then the exterior portion is twisted so that they cannot be pulled back through the holes. To remove the terminals, use a small pair of pliers to rotate the exterior portion of the terminal back to the same orientation as the holes; they will then readily drop through when the switch is held upside down.