US3715747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive keyboard electronics
Assignee: International Business Machines Corp
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Filing: 1971-12-30
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Granted: 1973-02-06
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Expires: 1991-12-30
Abstract
Abstract In a keyboard, key actuation causes a signal to be coupled from a drive pad to a sense pad. The output from the sense pad is connected to the encoder by a switching circuit. The encoder output goes to both the keyboard data register and through a delay circuit to set a latch which interrupts the switching circuit that was initiated by key depression. Effectively the elapsed time of the delay circuit represents the duration of coupling between the circuit of a depressed key and the data register through the encoding circuits. An overrun condition causes the transmission from encoder to keyboard data register to be inhibited. Although the keyboard is not physically locked by an overrun condition, an audible sound, which occurs upon each key actuation that results in data being received by the keyboard data register, is interrupted to inform the operator that entry of the coded data into such register has not been effected.
Inventors
- 👤 C Hanson
- 👤 J Ho
- 👤 M Houdek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:05
CPC Classifications
H; H03; H03M; H03M11/00; H03M11/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
137 words
An electronic keyboard apparatus comprising; a signal source; a sense pad; encoding means for receiving the output from said sense pad; connecting means for interconnecting the output of said sense pad with said encoding means; key operated means for selectively coupling said signal source to said sense pad upon actuation thereof; said connecting means including a switching circuit conditioned to initiate a signal to said encoding means upon receipt of a signal from said sense pad; and second connecting means connected to the output of said encoding means and to said switching circuit to decondition said switching circuit upon the occurrence of a signal received from the output of said encoding means, said second connecting means including delay means in series therewith, whereby the duration of interconnection between said encoding means and said sense pad is determined.
Claim 2
Dependent Claim
137 words
An electronic keyboard apparatus comprising; a signal source; a sense pad; encoding means for receiving the output from said sense pad; connecting means for interconnecting the output of said sense pad with said encoding means; key operated means for selectively coupling said signal source to said sense pad upon actuation thereof; said connecting means including a switching circuit conditioned to initiate a signal to said encoding means upon receipt of a signal from said sense pad; and second connecting means connected to the output of said encoding means and to said switching circuit to decondition said switching circuit upon the occurrence of a signal received from the output of said encoding means, said second connecting means including delay means in series therewith, whereby the duration of interconnection between said encoding means and said sense pad is determined.
Claim 3
Dependent Claim
137 words
An electronic keyboard apparatus comprising; a signal source; a sense pad; encoding means for receiving the output from said sense pad; connecting means for interconnecting the output of said sense pad with said encoding means; key operated means for selectively coupling said signal source to said sense pad upon actuation thereof; said connecting means including a switching circuit conditioned to initiate a signal to said encoding means upon receipt of a signal from said sense pad; and second connecting means connected to the output of said encoding means and to said switching circuit to decondition said switching circuit upon the occurrence of a signal received from the output of said encoding means, said second connecting means including delay means in series therewith, whereby the duration of interconnection between said encoding means and said sense pad is determined.
Claim 4
Dependent Claim
137 words
An electronic keyboard apparatus comprising; a signal source; a sense pad; encoding means for receiving the output from said sense pad; connecting means for interconnecting the output of said sense pad with said encoding means; key operated means for selectively coupling said signal source to said sense pad upon actuation thereof; said connecting means including a switching circuit conditioned to initiate a signal to said encoding means upon receipt of a signal from said sense pad; and second connecting means connected to the output of said encoding means and to said switching circuit to decondition said switching circuit upon the occurrence of a signal received from the output of said encoding means, said second connecting means including delay means in series therewith, whereby the duration of interconnection between said encoding means and said sense pad is determined.
Claim 5
Dependent Claim
25 words
The keyboard apparatus of claim 1 wherein said key operated means comprises a keystem operated capacitive coupling of said signal source to said sense pad.
Claim 6
Dependent Claim
38 words
The keyboard apparatus of claim 2 wherein said switching circuit includes a latch which is reset by the termination of an output signal from said sense pad and set by a signal received from said second connecting means.
Claim 7
Dependent Claim
68 words
The keyboard apparatus of claim 3 further comprising data register means connected to the encoded output of said encoding means; and sensing means connected to detect an overrun condition at said data register means upon the occurrence of an output from said encoding means; said sensing means having an output which inhibits communication between said encoding means and said data register means when an overrun condition is detected.
Claim 8
Dependent Claim
43 words
The keyboard apparatus of claim 4 further comprising audible means connected to normally generate an audible sound in response to each key depression and means to suppress generation of said audible sound when said sensing means detects the occurrence of an overrun condition.
Claim 9
Dependent Claim
89 words
An electronic keyboard apparatus comprising: a signal source; encoding means; data register means connected to receive and store encoded data from said encoding means; manually operable means for connecting said signal source to said encoding means; connecting means from the output of said encoding to said manually operable means; said connecting means including delay means in series therewith; and said connecting means operatively connected to said manually operable means to electrically disconnect said signal source from said encoding means upon receipt of an output signal from said encoding means.
Claim 10
Dependent Claim
89 words
An electronic keyboard apparatus comprising: a signal source; encoding means; data register means connected to receive and store encoded data from said encoding means; manually operable means for connecting said signal source to said encoding means; connecting means from the output of said encoding to said manually operable means; said connecting means including delay means in series therewith; and said connecting means operatively connected to said manually operable means to electrically disconnect said signal source from said encoding means upon receipt of an output signal from said encoding means.
Claim 11
Dependent Claim
35 words
The electronic keyboard apparatus of claim 6 further comprising audible means for issuing an audible sound responsive to each operation of said manually operable means which couples said signal source to said data register means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |