Micro Switch magnetic reed

Micro Switch magnetic reed
Manufacturer	Micro Switch
Introduced	1966
Switch type	Linear
Sense method	Magnetic
Keycap mount	"Selectric-style" keycap adapter metal pin

Description

Reed switches utilize physical and magnetic components. Two ferrous strips of metal are suspended in an inert gas using a vacuum tube-like enclosure. A magnetic field is applied to the perimeter of the tube to pull the strips together, resulting in switch actuation.

Micro Switch housings are labeled 'MICRO USA.' The switch can be opened via two small screws at the top of each unit. The red slider sits at an angle in the switch housing. The metal component of the red slider is the magnetic contact. There are markings on the side of the switch housings indicating multiple switch models. Examples include '6949 7A1HS' and '6950 7A1HS.' The first number is a production date code (year/week). The second is a keyswitch specific characteristic marking. The switch is linear, smooth, and uniform in feel; impressive if you consider its age.

Micro Switch magnetic reeds are plate mounted on metal rails. The 2 plastic pieces, which are threaded for screws, have a small lip. They hold the bottom part of the switch to the rail; the 'lid' on the switch also grabs the top of the rail. The switches are directly soldered into the PCB as whole units. The Micro Switch magnetic reeds differ from Honeywell switches -- the former have two pins and the latter possess 4. The Micro Switch may predate Honeywell variants. Micro Switch used a consistent keycap design. Using a 'stem slot' may have maintained backwards compatibility for some models.

Known switch variations:

7A1HA
7A1HS
7A1MS
7A1MT

The Micro Switch magnetic reed switch is made up of eleven parts:

Keyswitch box housing
Box housing top
Two screws
Two plastic female screw parts
Slider
Spring
Magnetic contact
Contact
Keycap mount pin

Keyboards

Burroughs D8585 [1]
Micro Switch 800210/68
Micro Switch RW-105432s [2]
Mohawk Data Sciences keyboard [3]
Mohawk Data Sciences Key to Tape keyboards

Gallery

Micro Switch magnetic reed slider with magnetic contact, spring, and box housing top on Burroughs D8585
Micro Switch magnetic reed parts on Micro Switch RW-10543
Micro Switch magnetic side view on Micro Switch RW-10543
Micro Switch magnetic reed top view on Micro Switch RW-10543
Micro Switch magnetic reed assembled side view on Micro Switch 800210/68
Micro Switch magnetic reed assembled top view on Micro Switch 800210/68
Micro Switch magnetic reed grey side view open on Burroughs D8585
Micro Switch magnetic reed grey top view open on Burroughs D8585
Micro Switch magnetic reed grey box housing open on Burroughs D8585
Micro Switch magnetic reed grey parts on Burroughs D8585