The Sasse 200MN Keyswitch
Posted: 12 Nov 2015, 03:07
The Tiki-100 was a computer made and sold in Norway from around 1984 to the late 80s. Being designed by people who used to work for Norsk Data and Tandberg Data, it was originally intended for this machine to use Siemens STB 11 keyswitches like the Tandberg terminals. However, as this was too expensive the team decided to go for cheaper Siemens-keycap compatible switches. According to the technical reference manual the choice landed on the Sasse 200MN.
As you can see in from the pictures, there is a plastic bar that is pushed sideways by the slider to actuate the switch. This mechanism gives the switch very interesting characteristics. It's linear, as the spring is the main counterforce at all times. However, at the actuation point the force requiered to push the plastic bar sideways and additional friction is added. The result is a split linear curve, starting out as a regular linear switch but bumps up to almost 100cN if you want to push it to and past the actuation point. From there it continues linearly, but with the added friction. Needless to say, it has a very "springy" feel to it, and it's pretty heavy and not really suited for touch-typing. On the other hand, if you have an application where you need to hold keys down for some time or if you like to slam the keys as you type, then it's actually pretty good.
As you can see in from the pictures, there is a plastic bar that is pushed sideways by the slider to actuate the switch. This mechanism gives the switch very interesting characteristics. It's linear, as the spring is the main counterforce at all times. However, at the actuation point the force requiered to push the plastic bar sideways and additional friction is added. The result is a split linear curve, starting out as a regular linear switch but bumps up to almost 100cN if you want to push it to and past the actuation point. From there it continues linearly, but with the added friction. Needless to say, it has a very "springy" feel to it, and it's pretty heavy and not really suited for touch-typing. On the other hand, if you have an application where you need to hold keys down for some time or if you like to slam the keys as you type, then it's actually pretty good.
Also, something just intrigues me about the shape of the switch.