Editing Metal contact switch (section)

====Ball contact====
A small number of switch types use a metal ball as the movable contact. These include [[Tokai MM9 series]] and its clones, [[Omron ball contact]], and non-keyboard switches from Sanwa and Hori sold in arcade buttons. No patent for any of these products has been found, and the exact operation remains a mystery. A metal ball, in some cases gold plated, bridges the gap between a pair of stationary contacts pressed into the base of the switch. The return spring sits above the ball, and on releasing the key, both pushes the slider up and raises the ball off one of the stationary terminals. This seems to defy the laws of physics. Ball contact switches are non-linear; Tokai switches are distinctly progressive rate with a sharp step in force before the force gradient increases; some other brands including Omron provide a much less distinct feel that is more like a wavering, imperfect linear design.

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File:Tokai MM9-1 -- opened.jpg        | [[Tokai MM9-1]] opened
File:Omron ball contact -- opened.jpg | [[Omron ball contact]] opened
File:Sanwa SW-68 -- opened.jpg        | Sanwa SW-68 arcade button switch; note the alternative design involving a guide ramp and tall stationary contacts, and the non-sealed shell
</gallery>