Communications: electrical – Audible indication – Percussion-type sound producer
Patent
1977-03-15
1979-01-23
Caldwell, Sr., John W.
Communications: electrical
Audible indication
Percussion-type sound producer
340365R, 178 17C, 3401463SY, G08C 100, G06F 302
Patent
active
041363361
ABSTRACT:
A keyboard apparatus includes a pair of juxtaposed tablets against which a single probe or signal pen may be applied through an overlay or overlays. Each tablet has a multiplicity of key segments defined on its surface at specified coordinates. Each segment is operable as a key as the probe is applied against a particular overlay which assumes an open position over a selected one of the tablets. A plurality of overlays are bound in a binder or fastener in the form of a book so that any overlay can assume an open position on either tablet. Each overlay has indicium segments on its surface which coorespond to the key segments and on which indicia such as letters or characters designating the key segments may be entered. When a particular overlay assumes an open position on one of the tablets, a probe may be applied against a desired indicium segment thereof, whereupon the probe senses a signal from the corresponding key segment. Means is provided for sensing which one of the overlays assumes an open position on the associated tablet and for producing a detection signal. A sensed key signal and the detection signal are combined to provide a digital signal which identifies the desired indicium segment on the particular overlay.
REFERENCES:
patent: 3158317 (1964-11-01), Alexander
patent: 3187321 (1965-06-01), Kameny
patent: 3560964 (1971-02-01), Bedell et al.
patent: 3956745 (1976-05-01), Ellis
Abe Kiyomi
Kameda Hidetoshi
Adams Bruce L.
Burns Robert E.
Caldwell Sr. John W.
Crosland Donnie L.
Lobato Emmanuel J.
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