FES-370, formerly referred to as “lever action” is a rare discrete mechanical keyboard switch from Fujitsu. It appears to be a metal dome switch the same as leaf spring but mounted vertically and with a lever actuator instead of the leaf spring. Keyboards with this switch are very rare; it appears to have been used in model FKB2930 (externally identical to FKB4700 “Peerless” keyboards), which is curious as analysis of Fujitsu keyboard series shows FKB2930 to be within the leaf spring series numbering range.
Detailed information in Japanese has been obtained by Kiyoto; more details will be provided once this has been processed. Numerically, they are one step after FES-360 (discrete leaf spring) and appear to be a way to provide discrete leaf spring switches in a lower-profile form factor.
The images below are preliminary until such time that better images are made available. The two switches below are from Chinese merchant cherry-jade and came from an unspecified keyboard collected from e-waste sent to China.
The return spring appears to be permanently attached to the plunger.
A US patent and a Japanese utility model have been found for this switch; it was introduced some years after leaf spring.
|US 4803316 A||Push button switch using dome spring and switch element thereof||1986-10-16||1989-02-07|
|JP H0615373 Y2||Pushbutton switch||1987-08-11||1994-04-20|