Editing Membrane keyboard (section)

====Spring over membrane====
In some older keyboards, a spring is placed inside the [[slider]]. As the key is depressed, this spring makes contact with the top membrane. After sufficient pressure is applied, this spring deforms the top membrane enough to make the switch. As the spring can be compressed further, overtravel is possible.

Spring-over-membrane switches typically use a second device to provide additional force; this will normally be a second helical spring, but [[buckling rubber sleeve]]s have also been used, such as in the [[Fujitsu Libertouch]]. [[Omron vase spring]] does use a single metal spring.

<gallery widths=250 heights=187>
File:Oriental Tech OK-100M -- membrane pressure springs.jpg | Membrane pressure springs in an [[Oriental Tech OK-100M]]
</gallery>

See: [[:Category:Spring-over-membrane switches|Spring-over-membrane switches]]