Title: Key arm mechanism

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Abstract: A key arm mechanism for keys of a typewriter or data entry device in which a uniform spring rate is achieved by varying the cross-sectional area of the key arms as a direct relation to the distance of the key support posts from a cantilever point. The entire key arm mechanism is formed of a unitary molded material. In one embodiment, the cross-sectional area of each key arm is uniform from the cantilever point to its associated key support post. In another embodiment, the cross-sectional area of each key arm decreases linearly from the cantilever point to its associated key support post. Uniform initial preload tension can be applied to the key arms by a slotted member which engages the ends of the key arms remote from the cantilever points. Non-uniform preload tension can be achieved by varying the height of some slots of the slotted member or by varying the height of the key arms at the ends thereof remote from the cantilever points. Adjustment of the preload tension can be achieved by an eccentric positioned adjacent the cantilever points.


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