Keyboard Patents

This is a list of patents notable for describing the mechanisms and features found on IBM and co keyboards. Whilst summarised on this page, please note that the actual patents will likely be very technical.

Patent #
Richard Hunter Harris
CA961541A, DE2224555C3, FR2138658B1, GB1348957A, IT950051B
Applied: 1971-05-21
Published: 1972-10-17
Catastrophically buckling compression column switch and actuator:
This is the original buckling springs patent. It does not share a lot in common with the later applied mechanisms used on the Model Fs and Ms, but it describes three related mechanisms based around a spring located in a barrel, like the later designs.
DE2246714A1, FR2153311B1, IT964141B, JPS4841277A
Applied: 1972-08-21
Published: 1974-08-14
Toggle mechanism:
This is the earliest patent available describing the IBM beam spring switch - the rest of world filing of US18358371A from 24 September 1971 (of which I am currently unable to locate). The components of the switch and the mechanism's assembly are described and several diagrams are given.
Richard Hunter Harris
CA1098947A, DE2860193D1, EP0001031B1, IT1109970B, JPS5741774B2
Applied: 1977-08-30
Published: 1978-10-03
Buckling spring torsional snap actuator:
This patent describes the IBM Model F's capacitive buckling springs switches, the applied form of Richard Hunter Harris' earlier patent regarding a similar design. Included are a written description of its operation and several diagrams.
Edwin T. Coleman, III
BR8404952A, DE3475025D1, EP0136488B1, JPH0561733B2
Applied: 1983-10-03
Published: 1985-07-09
Rocking switch actuator for a low force membrane contact switch:
This patent describes the IBM Model M's membrane buckling springs switches, an adaptation of Richard Hunter Harris' capacitive design for use with a membrane contact sheet. Included are a written description of its operation and several diagrams.
Edwin J. Selker, Joseph D. Rutledge
Applied: 1990-11-29
Published: 1996-05-28
Analog input device located in the primary typing area of a keyboard:
This is likely the original TrackPoint patent, developed by IBM, held by Lexmark for a time and currently assigned to Unicomp. The patent describes both a pointing stick device and under-keycap mounted device that can make use of strain gauges or various other alternative technologies for sensing movement with a pointing stick.