Percent calculator
OwnerJon L. Moffatinventor
Life of this patent
Estimating the term…
Abstract
This invention relates to a manually operable calculator; used to determine percent scores and to weight tests, comprised of a circular disc having a centrally pivoted rule. The disc has an outer periphery of numerals indicating per cent scores, the radii of numerals below 100 per cent indicating perfect scores, the radii of per cents other than one hundred indicating raw scores, and numerals on the rule corresponding to numerals on the radii below 100 per cent.
Claims6
A manually operable calculator to calculate per cent scores and to weight test scores comprised of a circular disc, a rule on either side of said disc centrally pivotally fastened to said disc to provide relative movement of three hundred and sixty degrees between said rule and said disc, each side of said disc including an outer circumference of numerals indicating from one to one hundred percent, the radii of the numeral extending inwardly from one hundred per cent comprising a series of numerals representing perfect raw scores, a series of interior circumferences of numerals each corresponding to one perfect raw score, each of said interior circumferences comprising a series of numerals representing test raw scores with one test raw score for each per cent on the outer circumference, each said test raw score on said interior circumference being the numerator, the perfect raw score on the same circumference being the denominator, the percentage score on the outer circumference of the radii of each such test raw score representing the percentage of the test raw score to the perfect raw score, numbers on the rule on each side of the disc representing various perfect scores.
A manually operable calculator comprising a manipulable array of the relation which individuals of a series of ratios representing actual raw scores compared with perfect raw scores bears to per cents, comprising:
- a disk having a series of per cents arranged on a plurality of angularly succeeding, equal length radii of an imaginary circle on the disk;
- a rule pivotally pinned to the disk at the origin of said imaginary cicle, the rule bearing a series of perfect raw scores, arranged in radiating line and a scale graduating the series along a radiating edge of the rule;
- a marker slidable along the rule to indicate a selection of the perfect raw score;
- a marker fixed on the rule and arranged to align with each of the individuals of said series of per cents, in consequence of pivotal movement of the rule with respect to the disk;
- a plurality of angularly spaced, individually radiating series of actual raw scores arranged on the disk in the following relationship:
- a. when the rule is angularly positioned with the fixed marker aligned with any particular individual of the series of percents,
- b. and the slidable marker indicates a particular perfect raw score,
- c. the graduated scale lies angularly beside one among said plurality of angularly spaced, individually radiating series of actual raw scores arranged on the disk, and
- d. the graduation on said graduation scale corresponding to the radius to which the slidable marker has been slid in (b) indicates the individual in said one series of (c) which most nearly equates to the actual raw score and multiplied by 100 equals the individual percent with which the fixed marker is aligned in (a), whereby
- when a particular raw score is to be converted to a percent score, the slidable marker may be set to align with the perfect raw score on the rule, and the rule may be pivoted until the said graduation of (d) indicates said particular raw score, whereupon the fixed marker will be found to be aligned with the percent corresponding to the ratio of the particular raw score to the perfect raw score.
Dependencies are inferred from the claim text.