Editing Omron B2R series (section)

==Description==
The switches are branded "OMRON" on the top, as well as being marked "B2R" and "JAPAN". The front of each switch is marked in white paint with what appears to be the model number, along with the lot number.

Known designs are [[SPST]] only, with a single reed module compartment. B2R features both upstroke and downstroke [[damping]] using separate rubber rings. Different models within the series provide illumination, [[alternate action]] and potentially an additional operation mode yet to be discovered.

B2R-M has a single-piece shell. The slider is inserted in from the top, and the reed module is inserted in from below. Considerable force is required to remove each of these parts, and damage may ensue from attempted disassembly, as noted later.

The downstroke is damped by a rectangular rubber pad which fits around the bottom of the slider and comes to rest against two small posts. The upstroke is damped by a second rubber part, which fits into a groove within the slider. A small piece of this part protrudes outwards above a corresponding protrusion in the slider itself, and this comes to a stop against a downward-facing ledge that is formed from the top of a shallow recess in the wall of the slider chamber.

The slider and reed module have separate chambers within the switch, with a wall in between them. The reed module comprises a plastic block into which the terminals are placed; in type M switches, this appears to be moulded as a single unit with the factory and cannot be disassembled, but in type G switches this block appears to be a separate carrier from which the terminals and reed capsule assembly can be removed.

The return spring (or springs, in illuminated variants) is offset to the back of the slider. In front of this is the magnet. The slider chamber features a special ridge, designed to hold in place either one or two return springs, depending on whether or not the switch is illuminated.

The front of the shell is recessed and has two guides, a notch, a step and a circular hollow post. Additional parts can be mounted onto the front. The slider does not protrude into this region and cannot influence its behaviour directly, but there is a tapered recess in the front of the slider that appears to be designed to rotate a lever, and one that could pivot from the hollow post directly below it. Possible explanations include an [[alternate action]] latching mechanism and a physical [[shift lock]] assembly.

===Keycap mount===
The keycap mount appears to be wholly proprietary. Ignoring the lamp fittings, it is a block around 5.2 mm wide by 5.0 mm deep and around 3.45 mm tall. Each of the four edges has a small vertical notch cut into it; this is difficult to measure, but it is around 0.7 mm by 0.7 mm (measurements vary from 0.64 to 0.8 mm). Additional grooves run around this block.

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File:Omron B2R-M -- keycap mount.jpg        | Keycap mount, demonstrated with a FANUC keycap
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===Dimensions===
Total height from the PCB standoffs to the top of the slider is around 29 mm. The shell is stepped and appears to be designed for two different mounting plate thicknesses or different PCB-to-plate distances, by way of different size holes in the plate. The mounting hole should be around 15.3 mm square, and the PCB-to-plate distance of 14.2 mm. The switch appears to support a slightly larger hole of 17.6 by 15.3 mm; this is in fact a pair of ridges that retain the sealing bellows sometimes seen on these switches. The maximum width and depth of the switch (above the plate) is around 17.6 by 17.7 mm.

The magnet is 6.4 mm wide by 5.9 mm tall by 2.8 mm deep.

===Age===
The age of the switch is not known. Type "B2R1-M" (which may or may not be part of this series) was discontinued in September 1988, while B2R series as a whole was discontinued in March 1993.<ref name="closed" />