| 摘要 |
A keyboard has column channels and row channels filled with displacement balls and having trough-like, semicircular cross-sections; this bottom contour of the channels is continued right into the intersection so that balls when displaced by key depressing will be retained in the respective channel, and not be deflected into any intersecting channel, so that the each key is positively identifiable by two switch closings, the switches being disposed for actuation at one end each of these channels. |
