Mitsumi standard mechanical double action

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Mitsumi standard mechanical double action

Manufacturer	Mitsumi
Family	Mitsumi standard mechanical
Switch type	Double action
Sense method	Metal leaf
Keycap mount	Proprietary cruciform
Switch mount	Plate mount

Mitsumi standard mechanical double action is a double action switch in the Mitsumi standard mechanical family.

Description

The two switchplates have different shaped actuator leaves, and a powerful spring inside the slide makes stage two very heavy. Stage one seems to be fairly light, at under 60 cN actuation.

This switch has been reported either at Deskthority or Geekhack in what was likely a typewriter, but the details are presently lost. This switch may explain why all Mitsumi standard mechanical switches feature holes for four terminals, but SPST is not ruled out.

Keyboards

• Smith-Corona Ultrasonic typewriter (for five keys, with white switchplates; most keys are KKR Type)<ref name="Imgur-Smith-Corona" />
• Olympia electronic compact 2 typewriter (for four keys, with white switchplates; and an extra lid detector switch)

Gallery

NOS switch from STRONIC in France; these can be found in typewriters and are used to detect what state the lid is in, open, partially closed, and fully closed. The long wires and 4 pin connector connect the the PCB and the switch itself is mounted inside the case of the typewriter.

• 
  Switch in its original condition, as shipped
• 
  Opened; both switchplates and the two-stage spring are visible
• 
  Actuator leaves: stage one (left) and stage two (right)

References

<references> <ref name="Imgur-Smith-Corona">Imgur — Smith-Corona Typewriter Keyboard Teardown</ref> </references>