Currency exchange calculator
OwnerGeorge W. Van De Wegheinventor
Life of this patent
Estimating the term…
Abstract
A hand calculator is described for converting monetary amounts from one currency to another comprising a slide with a plurality of parallelly disposed logarithmic scales thereon, a sleeve engaged with the slide and having an index means, and a cursor slidably engaged about a portion of the sleeve and having an index means thereon. For facilitating the calculation of gratuities as well as for converting currencies, the logarithmic scales are laterally oriented such that adjacent scales are displaced by a factor of 15 percent (or 0.15). In an alternative embodiment, the cursor has means for receiving a movable marker which may be used to mark a scale to which the user wishes to later refer.
Claims7
A currency exchange calculator for simultaneously displaying the monetary unis of two currencies that are related by a conversion factor comprising:
- (a) a slide having a plurality of parallel quasi-logarithmic scales thereon with at least one said scale being laterally displaced relative to another of said scales by a predetermined factor of displacement not related to the conversion factor, (b) a sleeve slidably engaged about at least a portion of said slide and including means for exposing at least a portion of each of said quasi-logarithmic scales and said sleeve further including a sleeve index means for indexing the position of said sleeve relative to at least one of said scales, and (c) a cursor slidably engaged about at least a portion of said sleeve and including a cursor index means for indexing the position of said cursor relative to at least one of said scales.
A currency exchange calculator for displaying monetary units of two currencies related by a conversion factor as well as a predetermined percentage gratuity in each of the same two currencies, comprising:
- a. a slide having
- i. one face with a first group of at least two logarithmic scales in parallel spaced-apart relationship, one of said scales being laterally displaced by the predetermined percentage with respect to another slide in said first group of slides,
- ii. an opposing face with a second group of at least two quasi-logarithmic scales, each associated with a predetermined cut number, in a parallel spaced-apart relationship which corresponds to the parallel spaced-apart relationship of said first group of scales such that the portion of each quasi-logarithmic scale with numbers marked thereon greather than or equal to the associated cut number is different in color from the remainder of the scale, and
- iii. a transparent plastic envelope extending about said two faces of said slide;
- b. a sleeve slidably engaged about at least a portion of said slide and including
- i. means for exposing at least a portion of at least two of said scales, and
- ii. sleeve index means for indexing the position of said sleeve relative to at least one of said scales;
- c. a transparent cursor slidably engaged about at least a portion of said sleeve and having
- i. cursor index means for indexing the position of said cursor relative to at least one of said scales, and
- ii. means for receiving a moveable marker;
- and
- d. a marker movably engaged within said receiving means of said cursor,
- whereby said slide may be slidably displaced within said sleeve such that the monetary unit of one currency appearing on one of said scales is displayed through said exposing means in coincidence with said sleeve index means, and said cursor may be slidably displaced about said sleeve such that the corresponding monetary unit of the second currency appearing on the same one of said scales is displayed through said exposing means and said cursor in coincidence with said cursor index means, and said marker may be displaced within said receiving means and positioned over a portion of the same one of said scales which is exposed by said exposing means.
Dependencies are inferred from the claim text.