US3717235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impact contact keyboard
Assignee: Singer Co
•
Filing: 1970-07-27
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Granted: 1973-02-20
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Expires: 1990-07-27
Abstract
Abstract A keyboard is disclosed which produces a signal in response to the depression of a selected key lever. In response to the depression of the selected key lever, a resilient spring contact is deflected away from a relatively fixed contact and released. The resilience of the resilient spring contact causes said spring contact to return towards the relatively fixed contact and make a momentary closure therewith. In response to the momentary closure, an electrical signal is produced during the charge time of a capacitor in series with the closing contacts. The capacitor is so chosen that it will be substantially fully charged in response to the closure of the contacts and no additional signal will result in the event that there should be any contact bounce or multiple closures thereof. An actuating pawl for actuating the resilient contact spring is attached to the key lever and a single spring is used to bias the actuating pawl and the key lever to their at rest positions. A bail which may be selectively positioned in cooperative relationship with a projection on the actuating pawl may be used to lock the key levers against actuation. A frame member is employed to pivot the pawl near the end of the down stroke of the key lever and thereby release the resilient contact spring. The cited frame member, the pawl and the key lever coact to provide a down stop limit for the key lever. Alternate selective means may be provided for locking selected key levers against actuation. In the structure shown, selected key levers are pivoted from a forward position while other key levers are pivoted from a rearward position. The circuit of the cited capacitor is designed to assure discharge of the cited capacitor well within the cycle time of operation of a given key lever.
Inventors
- 👤 H Dannatt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:03
CPC Classifications
B; B41; B41J; B41J5/00; B41J5/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
231 words
In a keyboard mechanism, the combination comprising: a. a key lever supported for limited reciprocal motion between an operative position and a normal nonoperative position; b. electrical contact means comprising: 1. a first contact member; and 2. a resilient contact member supported as a cantilever parallel to, insulated from, and spaced apart from said first contact member for making contact at least once with said first contact member when said resilient contact member is deflected away from said first contact member a predetermined distance and released by an actuator pawl moving to its operative position whereby momentary contact between the contact members occurs regardless of the time spent by the actuator pawl in its operative position; c. said actuator pawl pivotally secured to the key lever and having an end portion thereof cOnfigured to engage said resilient contact member and deflect it away from said first contact member a predetermined distance in response to the movement of said key lever to its operated position and to slidingly contact at an intermediate portion thereof, without causing contact between said contact members, the end of said resilient contact member when said key lever is moved to its normal non-operative position; and d. a control member coacting with said actuator pawl for disengaging said actuator pawl from said resilient contact member when said actuator pawl has deflected said resilient contact member a predetermined distance.
Claim 2
Dependent Claim
231 words
In a keyboard mechanism, the combination comprising: a. a key lever supported for limited reciprocal motion between an operative position and a normal nonoperative position; b. electrical contact means comprising: 1. a first contact member; and 2. a resilient contact member supported as a cantilever parallel to, insulated from, and spaced apart from said first contact member for making contact at least once with said first contact member when said resilient contact member is deflected away from said first contact member a predetermined distance and released by an actuator pawl moving to its operative position whereby momentary contact between the contact members occurs regardless of the time spent by the actuator pawl in its operative position; c. said actuator pawl pivotally secured to the key lever and having an end portion thereof cOnfigured to engage said resilient contact member and deflect it away from said first contact member a predetermined distance in response to the movement of said key lever to its operated position and to slidingly contact at an intermediate portion thereof, without causing contact between said contact members, the end of said resilient contact member when said key lever is moved to its normal non-operative position; and d. a control member coacting with said actuator pawl for disengaging said actuator pawl from said resilient contact member when said actuator pawl has deflected said resilient contact member a predetermined distance.
Claim 3
Dependent Claim
30 words
In a keyboard mechanism, the combination comprising: a. a key lever supported for limited reciprocal motion between an operative position and a normal nonoperative position; b. electrical contact means comprising:
Claim 4
Dependent Claim
30 words
In a keyboard mechanism, the combination comprising: a. a key lever supported for limited reciprocal motion between an operative position and a normal nonoperative position; b. electrical contact means comprising:
Claim 5
Dependent Claim
5 words
a first contact member; and
Claim 6
Dependent Claim
5 words
a first contact member; and
Claim 7
Dependent Claim
43 words
The combination as set forth in claim 1 wherein said control member cooperates with the key lever to limit the reciprocal movement of the key lever to an operated position after the associated actuator pawl has been disengaged from the resilient contact member.
Claim 8
Dependent Claim
194 words
a resilient contact member supported as a cantilever parallel to, insulated from, and spaced apart from said first contact member for making contact at least once with said first contact member when said resilient contact member is deflected away from said first contact member a predetermined distance and released by an actuator pawl moving to its operative position whereby momentary contact between the contact members occurs regardless of the time spent by the actuator pawl in its operative position; c. said actuator pawl pivotally secured to the key lever and having an end portion thereof cOnfigured to engage said resilient contact member and deflect it away from said first contact member a predetermined distance in response to the movement of said key lever to its operated position and to slidingly contact at an intermediate portion thereof, without causing contact between said contact members, the end of said resilient contact member when said key lever is moved to its normal non-operative position; and d. a control member coacting with said actuator pawl for disengaging said actuator pawl from said resilient contact member when said actuator pawl has deflected said resilient contact member a predetermined distance.
Claim 9
Dependent Claim
194 words
a resilient contact member supported as a cantilever parallel to, insulated from, and spaced apart from said first contact member for making contact at least once with said first contact member when said resilient contact member is deflected away from said first contact member a predetermined distance and released by an actuator pawl moving to its operative position whereby momentary contact between the contact members occurs regardless of the time spent by the actuator pawl in its operative position; c. said actuator pawl pivotally secured to the key lever and having an end portion thereof cOnfigured to engage said resilient contact member and deflect it away from said first contact member a predetermined distance in response to the movement of said key lever to its operated position and to slidingly contact at an intermediate portion thereof, without causing contact between said contact members, the end of said resilient contact member when said key lever is moved to its normal non-operative position; and d. a control member coacting with said actuator pawl for disengaging said actuator pawl from said resilient contact member when said actuator pawl has deflected said resilient contact member a predetermined distance.
Claim 10
Dependent Claim
25 words
The combination as set forth in claim 2 and including bias means urging the actuator pawl to pivot towards engagement with the resilient contact member.
Claim 11
Dependent Claim
30 words
The combination as set forth in claim 3 wherein said bias means includes a spring supported substantially parallel to the key lever and in continuous contact with the actuator pawl.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |