US4545022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fractional calculator
Assignee: Individual
•
Filing: 1983-02-10
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Granted: 1985-10-01
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Expires: 2003-02-10
Abstract
Abstract A fractional calculator (10) has a keyboard (12) with numeral keys (18) and denominator keys (20). Through use of the numeral keys (18) and the denominator keys (20), fractional inputs may be entered into the calculator and calculations carried out on the inputs through use of function keys (22). A decimal/U.S. toggle key (26) allows the calculator to be used in either a conventional decimal mode or a fractional mode. When the calculator is used in a fractional mode, key (30) is used to differentiate between integers and numerators of fractions entered by means of the numeral keys (18). Key (28) may be used to distinguish between feet and inches in mixed unit entries during fractional mode operation. Display (14) includes indicators (38, 39, 40, 42, 44) for different modes of operation and different types of entries.
Inventors
- 👤 James T. Hughins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:51
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/14; G06F3/1407; G06F15/00; G06F15/02; G06F15/025; G06F15/0258
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
144 words
A calculator for fractions, which comprises a keyboard including a plurality of number keys, a plurality of denominator keys having a preselected range of numbers, a plurality of function keys for selecting operations to be performed on whole numbers and fractions selected by actuation of said number keys for the whole numbers followed by actuation of a numerator function key in combination with said number keys for the numerator of the fraction and then selecting one of said preselected denominator numbers from said denominator keys, a display for showing entry of the selected numbers and fractions and results of the selected operations, and circuit means operatively connected to said keyboard and said display for carrying out the selected operations on the selected numbers and fractions, and for displaying the selected numbers, the selected operation, and the results of the selected operation on said display.
Claim 2
Dependent Claim
144 words
A calculator for fractions, which comprises a keyboard including a plurality of number keys, a plurality of denominator keys having a preselected range of numbers, a plurality of function keys for selecting operations to be performed on whole numbers and fractions selected by actuation of said number keys for the whole numbers followed by actuation of a numerator function key in combination with said number keys for the numerator of the fraction and then selecting one of said preselected denominator numbers from said denominator keys, a display for showing entry of the selected numbers and fractions and results of the selected operations, and circuit means operatively connected to said keyboard and said display for carrying out the selected operations on the selected numbers and fractions, and for displaying the selected numbers, the selected operation, and the results of the selected operation on said display.
Claim 3
Dependent Claim
23 words
The calculator for fractions of claim 1 in which said keyboard includes a selection key for choosing between decimal operation and fractional operation.
Claim 4
Dependent Claim
25 words
The calculator for fractions of claim 1 in which said keyboard includes a key for distinguishing entry of an integer and entry of a fraction.
Claim 5
Dependent Claim
26 words
The calculator of claim 1 in which said keyboard includes a key for reducing a fraction to the closest whole number numerator with a selected denominator.
Claim 6
Dependent Claim
20 words
The calculator of claim 1 in which said keyboard includes a key for selecting between mixed units for an entry.
Claim 7
Dependent Claim
33 words
The calculator of claim 1 in which said keyboard includes at least one key for selecting between different types of entries and said display includes an indicator for each different type of entry.
Claim 8
Dependent Claim
16 words
The calculator of claim 6 in which the different types of entries include integers and fractions.
Claim 9
Dependent Claim
20 words
The calculator of claim 7 in which the different types of entries include entries in feet and entries in inches.
Claim 10
Dependent Claim
34 words
The calculator of claim 6 in which said keyboard additionally includes at least one key for selecting between different modes of operation and said display includes an indicator for each different mode of operation.
Claim 11
Dependent Claim
17 words
The calculator of claim 9 in which the different modes of operation include decimal and fractional operation.
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) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |