Key shift mechanism

Claim 1

A key shift mechanism for a typewriter keyboard, said mechanism comprising: a. a shift key lever means including a first slide member and a shift key lever having a first end vertically movable between an up position and a down position for controlling said first slide member to generate a shift code representing upper case characters when said shift key lever is moved from said up position to said down position; b. an unshift key lever means including a second slide member and an unshift key Lever mounted substantially parallel to said shift key lever and having a second end vertically movable between an up position and a down position for controlling said second slide member to generate an unshift code representing lower case characters when said unshift key lever is moved from said up position to said down position; c. a rocker arm lever pivotally mounted about a given point along its length and coupled at one end to said first end of said shift key lever and connected at the other end thereof to said second end of said unshift key lever for maintaining said first end of said shift key lever and said second end of said unshift key lever in phase opposition to each other; d. spring means coupled to said first end of said shift key lever and said second end of said unshift key lever for yieldingly urging said first and second ends towards said up position; and e. button means connected near said first end of said shift key lever for controlling the vertical motion of said first end of said shift key lever whereby said rocker arm lever coacts with said unshift key lever to cause said second slide member to generate said unshift code when said first end of said shift key lever is moved from said down position to said up position.