|This article requires additional photographic illustration — at the very least needs a proper picture for infobox, once someone has collected several different types|
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|Sense method||Metal leaf|
|Switch mount||Plate mount|
|Patents||US 4339643 (1980)|
In their 1982 catalogue, Cherry listed three different sizes of keyswitch: Cherry M7 ("Standard Mounting Height"), Cherry M8 ("Super Low Profile") and Cherry M9 ("Low Profile"). Cherry M9 switches are designed to sit almost entirely below the plate, with a 9.14 mm distance from the top of the plate to the top of the PCB (down from 17.4 mm in the Cherry M7). From the diagram, this gives a total switch height of 12 mm. This corresponds closely with the 11.6 mm overall height of the Cherry MX switch, but with a requirement of a taller PCB−plate gap. Less than 3 mm of the switch is above the plate.
The MX shell design, including its retention clips and four top release holes, is quite similar to the M9's. However, the M9 is usually mounted with latches on top and bottom, rather than the sides, as with the MX.
The switch shell and slider can accommodate separate contact mechanisms for two circuits. The stem is MX mount.
The M9 appears to be the least used of the three types of Cherry switches. According to dates on shipping boxes, it was produced until at least 1985.
US patent 4339643 filed in 1980 describes a tactile double-action version and claims that this switch has hysteresis; no explanation for the hysteresis is immediately obvious and the term only appears once in the text of the patent.
- Triumph-Adler Alpha 610 typewriter
The example below appears to be derived from a linear double-action switch, as one actuator ramp deliberately holds the contact open longer. The parts for the second stage are not present.
- Imgur — Cherry Switchery Dated 2013. Retrieved 2015-07-23.