Oki Tactile Gourd Spring

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Oki Tactile Gourd Spring

Manufacturer	Oki Electric
Inventor	Kazuo Aoki Toshimi Chiba Sadao Tachibana Yasushi Nagatomo
Switch type	Clicky
Sense method	Spring over membrane
Peak force	70 cN
Patents	US4927990

History

Developed by Oki Electric in the late 1980's as an extension to the Oki Gourd Spring switch to provide audible and tactile feedback. It's important to note that the patent directly references the IBM Model M switch tech, the IBM buckling spring (including cut-away actuation diagrams and a force curve).

These switches are only found in keyboards that were manufactured by Oki Electric, sometimes as OEM for other companies. Some electric typewriters made by Oki Electric might also have Oki Gourd Spring switches.

The term "Gourd Spring" seems to have originated from MouseFan of the Japanese keyboard community.<ref name="MouseFan" />

Key feel

Smooth barrel with an audible and tactile instant before the spring fully depresses on the sense membrane.

Keycaps

All known keycaps are dye sublimated.

Availability

It is unlikely that Oki Electric still produces these switches, and since they are not available as single units, the entire keyboard has to be formed. Known keyboards are from the early 1990's.

Keyboards

• Oki HMB-35957-14 (internal module is HMB-35957U-22)
• Oki HMB-35957U-22
• IBM KMB88102 (internal module is HMB-35957U-22)

Gallery

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  Tactile gourd springs

References

<references> <ref name="MouseFan">MouseFan — Reference to "Gourd Spring" on the OKI GA2260 (Japanese) Retrieved 2015-07-31.</ref> </references>