| 摘要 |
A keyboard having a plurality of rows of depressable keys whose key tops define a surface of concave profile curved about an axis. The concave profile is achieved with key tops and key stems of identical configuration by maintaining a key holder plate which carries the key stems in a concave profile. The concave profile of the key holder plate is produced by forming the plate with graduated flexibility across its width and mounting it on a substantially rigid base so that a region of the plate located midway between its edges is drawn to a position outside the plane containing the edges of the plate by means of a plurality of fasteners between the base and a plate located along its length.
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