The Flawed Design of Typewriter Keyboards

Conventional PC keyboard designs are based upon a fundamental "typing core" inherited from the 150-year-old mechanical typewriter. That typing core consists of a monolithic "character" key array, with "carriage control" keys abutting the sides, and a spacebar key positioned below. Beyond the aforesaid heirloom keys, PC keyboard typing cores include other essential keys in the spacebar-row.

When a character key was depressed on a mechanical typewriter keyboard, it actuated the end of the type lever upon which that key top was fixed. In turn, that type lever actuated a respective type hammer that struck the ink ribbon with a type slug which impressed that specific character mark on the paper.

Because the type levers had to pass by each other, none of the keys in the typewriter character key array could be positioned in direct vertical alignment with any other key. As a result of the aforementioned mechanical imperative, the typewriter character key array had an uneven horizontal displacement between the four rows of character keys. Progressing downward, between the rows there is a one-half one-quarter one-half rightward displacement. That irregular "keystagger" gave rise to crooked oblique key columns.

The PC keyboard perpetuates that asymmetric mechanical configuration. Modern typists are bound to that design by a history of 150 years. Notwithstanding, the 19th-century typewriter keyboard configuration does not provide optimal human biomechanics, as evidenced by its protracted association with carpal tunnel syndrome.

The irregular oblique key columns of conventional PC typing cores are a hindrance to natural motion. The jagged asymmetric monolithic array of character keys is the source of two major flaws in mechanical typewriter keyboard configuration.

First Design Flaw: the left-hand touch-typing assignments (left of the oblique midline) are very stressful. Those assignments require a user to negotiate vertical reaches along contrarily angled (right-handed) key columns. An operator must "crab" their fingers along the backswept slope of the key columns. Any vertical reach for keys outside of home-row requires a coordinated lateral movement of the left forearm.

A typist maintaining "home position" (no lateral forearm movement) and following the backswept slope of the key columns would be bending their left hand outwardly at the wrist. The hand bones are thrust out of alignment with the ulnar bone of the forearm. This unnatural wrist bending is called "ulnar deviation"... that is a bad thing!

The left-hand fingers of an operator negotiating a conventional keyboard work harder than those of the right hand. Upward vertical reaches along contrarily angled key columns require inner fingers to "hurdle" over outer fingers and downward reaches require outer fingers to "crowd" under inner fingers.

Second Design Flaw: the right-hand touch-typing assignments compel typists, reaching out of home-row, to slightly deviate their fingertips laterally off-axis while following the inconsistent horizontal displacement of keys within the crooked oblique key columns.

As a typist's fingers contract or extend, while making vertical reaches out of home-row, the fingertips naturally move in straight paths. The constant skewing required to connect with an outlying key is stressful and when not effected results in a common error: an off-center keystroke actuating an abutting key rather than the targeted key when making a vertical reach.

Ronald Earl Walker - Mechanical Keyboard Critic