Editing IBM buckling rubber sleeve (section)

==Design==

===Concept===
IBM buckling sleeves switches are membrane-driven and seemingly derive from the same patents and/or copyright shared with membrane buckling springs as their host devices often cite 1984 as the copyright date just like many buckling spring Model Ms. The sleeves are very tactile and are of medium weighting but do not feature part-way actuation as a property. Like membrane or conductive rubber dome switches, the user is required to bottom out to actuate but the experience of doing so is different to rubber dome switches and even some conceptually similar buckling rubber sleeve based switches. The key differences:

# Compared to rubber dome switches, the rubber component sits externally from the assembly on top of a barrel plate and is used for providing tactility and return force for the keycap only - they play no part in direct actuation. Most non-capacitive rubber dome switches are required to play a role in bridging the connection with the sensing mechanism.
# IBM sleeves are outwardly-expanding conical shaped and are sculpted so that the rubber at the top buckles to rest aside the bottom rubber instead of all 'squishing' at the bottom.
# Unlike the conceptually close [[Mitsumi KPQ Type]] switches, IBM's design lacks the conductive rubber foot on the bottom of its actuation element (keycap rod or barrel slider), eliminating another possible element that could dampen a solid bottoming out feel.

Instead, a rod on the keycap or a slider in the barrel (depending on implementation) provides a solid interface to the membrane to close the circuit<ref name="sharkbucklingsleeveswiki" />.

===Sleeve sizes===
IBM buckling sleeves have been employed on a multitude of devices, in some cases requiring a specific size (or gauge, if you will) of sleeve. 5 distinct types of sleeves have been documented, although they may be subject to slightly differing rubber thickness or colour.

[[File:Shark IBM sleeve gauges.jpg|720px|center]]