Editing Sealed terminals

'''Sealed terminals''' are a feature or option of a number of switch families. The purpose is not known. RAFI note the following in the [[:File:RAFI Electromechanical Components 2001, section 5, excerpt RS 74 and 76.pdf|Electromechanical Components 2001 catalogue]]:

<blockquote>
Following momentary/latching keyswitches can be flow-soldered:<br>
*Momentary/latching keyswitches with '''sealed''' bottom and sealed terminals:
**Momentary keyswitches RS 74 M with increased ESD-strength
**Keylock, code and rotary switches
*All momentary/latching keyswitches RS 76 C (Hall-IC)
</blockquote>

The sealant is a firm but not strong substance, typically red in colour. Depending on the switch, scraping it with a sharp implement can cause it to flake (RS 74 M) or scratch, but it can be scratch-resistant.

With [[Alps SKCC series]] and [[General Instrument Series S950]], the base of the switch contains a recess surrounding the terminals that appears to be placed there to contain the sealant. RS 74 M sealed switches have small recesses around the legs to hold the sealant, instead of the typical large holes through which the legs pass.

[http://www.google.com/patents/US4760225 US patent 4760225] filed by [[Alps Electric]] (in relation to [[Alps common mount low profile]]) is titled "Push button switch having a frame member for preventing solder penetration of switch contacts", which ties in with the possibility that the increased level of manufacturing automation required some means of preventing the solder entering the switch during wave soldering.

With [[SMK J-M0404 series]] switches, the sealant secures the terminals sufficiently that they can be reinserted into the upper shell with ease, making light work of the typically fraught process of trying to reassemble an SMK switch. The widespread occurrence of this sealant in easy-to-assemble switches suggests that is is not a manufacturing aid, however.

==Gallery==
<gallery widths=250 heights=187>
File:Sealed terminals -- RAFI RS 74 M.jpg  | [[RAFI RS 74 M]] "with increased ESD-strength" (presumed to be 3.12961.001)
File:Sealed terminals -- SKCC Lock.jpg     | [[Alps SKCC Lock]]
File:Sealed terminals -- SMK J-M0404.jpg   | [[SMK J-M0404 series]], unsealed (left) and sealed (right)
File:General Instrument S95010 -- base.jpg | [[General Instrument Series S950|General Instrument S95010]] with uncharacteristic clear sealant
</gallery>

[[Category:Keyboard terms]]