Patent US3781820A successfully refreshed from Google Patents.
US3781820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portable electronic calculator
Assignee: HP Inc
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Filing: 1972-05-30
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Granted: 1973-12-25
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Expires: 1992-05-30
Abstract
Abstract An electronic calculator is provided with an enter key, a change sign and a store key. The enter key causes a stack memory to be pushed down, duplicating information from a keyboard register into a first memory register. The first data key actuated after the enter key causes the keyboard register to be cleared before the new data is entered into that register. The change sign key operates in conjunction with a keyboard register of the main stack memory to change the sign of a number contained therein. If this key is actuated subsequent to the performance of a function and data is entered after the key is actuated, then the sign of the new entry will be changed rather than the sign of the previous contents of the keyboard register. The store key causes information in the keyboard register to be duplicated into an auxiliary memory. The first data key actuated after the store key causes the keyboard register to be cleared before the new data is entered.
Inventors
- 👤 D Cochran
- 👤 T Osborne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:41
CPC Classifications
G; G06; G06F; G06F15/00; G06F15/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
81 words
In an electronic calculator including a stack memory for storing a stack of data words, shifting means for pushing the words in the stack up and down, digit keys for inputting data into the top word in the stack, and an enter key, the improvement comprising: control means connected to the enter key and the shifting means for pushing down the stack and leaving the word in the top of the stack unchanged in response to actuation of the enter key.
Claim 2
Dependent Claim
81 words
In an electronic calculator including a stack memory for storing a stack of data words, shifting means for pushing the words in the stack up and down, digit keys for inputting data into the top word in the stack, and an enter key, the improvement comprising: control means connected to the enter key and the shifting means for pushing down the stack and leaving the word in the top of the stack unchanged in response to actuation of the enter key.
Claim 3
Dependent Claim
48 words
In an electronic calculator as in claim 1, the further improvement comprising clearing means connected to the stack memory and the digit keys for clearing the top of the stack word in response to the actuation of a digit key subsequent to the actuation of the enter key.
Claim 4
Dependent Claim
84 words
In an electronic calculator as in claim 2 including function keys, the further improvement comprising function means connected to the stack memory and the function keys for combining the word in the top of the stack with the word in the next memory position, entering the result of the combination into the top of the stack and pushing up the rest of the words in the stack in response to the actuation of a function key subsequent to the actuation of the enter key.
Claim 5
Dependent Claim
45 words
In an electronic calculator as in claim 3 the further improvement comprising logic means connected to the shifting means and the function means for pushing the stack down in response to the actuation of a data key subsequent to the actuation of a function key.
Claim 6
Dependent Claim
80 words
In an electronic calculator as in claim 2 including function keys, the further improvement comprising function means connected to the stack memory and the function keys for combining the word in the top of the stack with the word in the next memory position, entering the result of the combination into said next memory position and pushing up the words in the stack in response to the actuation of a function key subsequent to the actuation of the enter key.
Claim 7
Dependent Claim
45 words
In an electronic calculator as in claim 5, the further improvement comprising logic means connected to the shifting means and the function means for pushing the stack down in response to the actuation of a data key subsequent to the actuation of a function key.
Claim 8
Dependent Claim
164 words
In an electronic calculator including a stack memory for storing data words, each word including information representing the algebraic sign of the word comprising at least one bit, digit keys for inputting data into the top word in the stack, and shifting means for pushing the words in the stack up and down, the improvement comprising: a change sign key; complementing means connected to the stack memory for complementing The sign information in the word in the top of the stack in response to actuation of the change sign key; and control means connected to the complementing means and the digit keys for recomplementing the sign information in the word shifted from the top of the stack to the next memory position in response to the actuation of a data key after the actuation of the change sign key and for complementing the sign information in the word containing data inputted into the stack memory in response to said actuation of a data key.
Claim 9
Dependent Claim
164 words
In an electronic calculator including a stack memory for storing data words, each word including information representing the algebraic sign of the word comprising at least one bit, digit keys for inputting data into the top word in the stack, and shifting means for pushing the words in the stack up and down, the improvement comprising: a change sign key; complementing means connected to the stack memory for complementing The sign information in the word in the top of the stack in response to actuation of the change sign key; and control means connected to the complementing means and the digit keys for recomplementing the sign information in the word shifted from the top of the stack to the next memory position in response to the actuation of a data key after the actuation of the change sign key and for complementing the sign information in the word containing data inputted into the stack memory in response to said actuation of a data key.
Claim 10
Dependent Claim
48 words
In an electronic calculator as in claim 7 including function keys, the further improvement comprising: logic means connected to the function keys and the control means for presetting the control means to respond to the actuation of a data key after the actuation of the change sign key.
Claim 11
Dependent Claim
95 words
In an electronic calculator including a stack memory for storing a stack of data words, shifting means for pushing the words in the stack up and down, digit keys for inputting data into the top word in the stack, an auxiliary memory, and a store key, the improvement comprising: control means connected to the store key, the stack memory and the auxiliary memory for duplicating the word in the top of the stack into the auxiliary memory, leaving the word in the top of the stack unchanged, in response to actuation of the store key.
Claim 12
Dependent Claim
95 words
In an electronic calculator including a stack memory for storing a stack of data words, shifting means for pushing the words in the stack up and down, digit keys for inputting data into the top word in the stack, an auxiliary memory, and a store key, the improvement comprising: control means connected to the store key, the stack memory and the auxiliary memory for duplicating the word in the top of the stack into the auxiliary memory, leaving the word in the top of the stack unchanged, in response to actuation of the store key.
Claim 13
Dependent Claim
48 words
In an electronic calculator as in claim 9, the further improvement comprising clearing means connected to the stack memory and the digit keys for clearing the top of the stack word in response to the actuation of a digit key subsequent to the actuation of the store key.
Claim 14
Dependent Claim
84 words
In an electronic calculator as in claim 10 including function keys, the further improvement comprising function means connected to the stack memory and the function keys for combining the word in the top of the stack with the word in the next memory position, entering the result of the combination into the top of the stack and pushing up the rest of the words in the stack in response to the actuation of a function key subsequent to the actuation of the store key.
Claim 15
Dependent Claim
45 words
In an electronic calculator as in claim 11 the further improvement comprising logic means connected to the shifting means and the function means for pushing the stack down in response to the actuation of a data key subsequent to the actuation of a function key.
Claim 16
Dependent Claim
80 words
In an electronic calculator as in claim 10 including function keys, the further improvement comprising function means connected to the stack memory and the function keys for combining the word in the top of the stack with the word in the next memory position, entering the result of the combination into said next memory position and pushing up the words in the stack in response to the actuation of a function key subsequent to the actuation of the enter key.
Claim 17
Dependent Claim
45 words
In an electronic calculator as in claim 13 the further improvement comprising logic means connected to the shifting means and the function means for pushing the stack down in response to the actuation of a data key subsequent to the actuation of a function key.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |