Alps AKC
Alps AKC switches, commonly referred to as “Alps spring bridge” are a mid-1970s series of Alps switches.
Characteristics
The switch consists of a stem with a metal rod through for attaching a keycap, and a recess in which a fine, gold-plated spring rests slightly deformed. As the stem is pushed, the spring brushes against and bridges the contacts3), which are tinned pads on a square chunk of PCB substrate. This PCB substrate passes through a slot on a key module's PCB and is bridged to it. Return force is provided externally, and care should be taken when removing keycaps (which have a strong grip) as flyaway springs are incredibly likely.
Several variations exist - the metal-topped version, as seen in the infobox, appears to be first. There was a later all-plastic version4). There also appears to have been a keyboard variant, based on the AKB-3000 series keyboard advertisement. This has a larger quoted travel than any instance of the switch seen so far so could have a differently sized housing.
The switch could also be ordered as a set module under part code “AKM”. This can often be seen in calculators.
Additional Information
The switch was likely in production from as early as 19735) to 19796). It was replaced by Alps SKCC Gray.
The switch could sometimes be seen with a mount adapter allowing for cruciform mount keycaps to be fitted.
Gallery
