Check digit calculator

Claim 2

Check digit calculator for use with a standard modulo ten type check digit system, comprising in combination means for storing the 10 numerals 0 through 9, means for displaying only one of said numerals at a time, and means for selecting that one of said numerals which represents the modulo-10 check digit of a given whole number by manipulating said storing means relative to said display means in accordance with said modulo-10 formula as applied to said given whole number, which comprises means for alternately Doubling and adding the individual digits of said given whole number taken in sequence, said doubled digits 5 through 9 being represented by the sum of the digits of the double quantity, said numeral representing the check digit being the tens complement of the alternately accumulated total.

Claim 3

Check digit calculator according to claim 1, further comprising a face plate, a disk mounted for rotating behind said face plate, and wherein said storing means comprises said numerals printed on said disk, and wherein said displaying means comprises a window in said face plate.

Claim 4

Check digit calculator according to claim 2, wherein said means for alternately doubling and adding comprises separate scales marked on opposite sides of an arcuate opening in said face plate, and said disk has an arcuate series of depressions concentric with said arcuate opening, said depressions being radially aligned wiith said scale markings.

Claim 5

Check digit calculator according to claim 3, wherein said add scale comprises numbers one through nine spaced arcuately at equal intervals, and said doubling scale also comprises numbers one through nine but spaced arcuately at double said add-scale intervals, said depressions being 18 in number with one half being marked to be readily distinguishable from the other half, said arcuate opening extending one of said add-scale intervals beyond the ends of said add-scale numbers.

Claim 6

Check digit calculator according to claim 4, wherein said disk numerals are arranged in inverse numerical order relative to said add-scale numbers and spaced arcuately at equal intervals that are arcuately equal to said add-scale intervals.

Claim 7

Check digit calculator according to claim 1, wherein said storing means comprises a diode matrix, said displaying means comprises a group of illuminable elements for forming said numerals by being illuminated in different combinations, and wherein said alternate doubling and adding means comprises a rotatable switch having 10 positions equally spaced around a radial contact arm, means for moving said arm in one direction of rotation only in steps of 36* or whole multiples thereof, circuit means for connecting said switch positions to said matrix, alternately selectable doubling and add scales corresponding with nine of said ten switch positions, said add scale comprising the numbers one through nine consecutively indicating said nine switch postions, and said doubling scale comprising the numbers one through nine indicating sequentially the same switch positions as the add-scale numbers two, four, six, eight, one, three, five, seven and nine respectively, all whereby said rotatable switch may be manipulated in steps as determined by said alternately selectable scales and in accordance with said modulo-10 formula.

Claim 8

Check digit calculator according to claim 6, wherein said alternate doubling and adding means further comprises means for indicating which of said alternate scales should be employed during said modular ten formula procedure, and a zero switch with circuit means for shifting said indicating means to the opposite scale when a zero digit is encountered in said given whole number.

Claim 9

Check digit calculator according to claim 1, wherein said storing means comprises a plurality of contacts on a rotary switch, and said displaying means comprises a group of illuminable elements for forming said numerals by being illuminated in different combinations, and wherein said alternate doubling and adding means comprises a rotatable switch arm for contacting said contacts individually, means for moving said arm in one direction only in steps of 36* or whole multiples thereof, circuit means including a diode matrix for connecting said contacts to said illuminable elements, and alternately selectable doubling and Add scales corresponding with all except one of said contacts, said add scale comprising the numbers one through nine consecutively indicating nine of said contacts, and said doubling scale comprising the numbers one through nine indicating sequentially the same contacts as said add-scale numbers two, four, six, eight, one, three, five, seven, and nine respectively, all whereby said rotatable switch arm may be manipulated in steps as determined in accordance with said alternately selectable scales and in accordance with said modulo-ten formula.

Claim 10

Check digit calculator for use with a standard modulo-ten type check digit system, comprising in combination a flat body member having a face plate, a disk mounted for rotation behind said face plate, an arcuate opening in said face plate concentric with said disk, a single numeral-sized window in said face plate located diametrically across from said arcuate opening, numbers one through nine spaced arcuately at equal angular intervals on one side of said arcuate opening and forming an add scale on said face plate, numbers one through nine spaced arcuately at twice said equal angular interval from one another and located radially aligned with various of said add-scale numbers but on the other side of said arcuate opening and forming a multiply scale, check digit numerals one through nine plus zero located on said disk and spaced on a concentric arc with equal angular intervals as said add-scale numbers and being situated for individual display through said window, 18 depressions on said disk located on a concentric arc for coinciding with said arcuate opening and being arcuately spaced apart at equal angular intervals equal to the intervals of said add scale, and a colored background strip for one half of said depressions in order to indicate when the direction of rotation of said disk should be reversed, said arcuate opening extending circumferentially an angular amount such that a single add-scale angular interval of rotation of said disk may be added at either end of said add scale by manipulation using the end one of said depressions opposite the one or the nine of said add scale, all whereby said disk may be manipulated using said depressions in conjunction with said multiply and add scales plus said colored strip and in accordance with said modulo-ten formula.

Claim 11

Check digit calculator for use with a standard modulo-ten type check digit system, comprising in combination a flat body member having a face plate, a disk mounted for rotation behind said face plate, an arcuate opening in said face plate concentric with said disk, a single numeral-sized window in said face plate located diametrically across from said arcuate opening, numbers one through nine spaced arcuately at equal angular intervals on one side of said arcuate opening and forming an add scale on said face plate, numbers one through nine spaced arcuately at twice said equal angular interval from one another and located radially aligned with various of said add-scale numbers but on the other side of said arcuate opening and forming a multiply scale, check digit numerals one through nine plus zero located on said disk and spaced on a concentric arc with equal angular intervals as said add-scale numbers and being situated for individual display through said window, 18 depressions on said disk located on a concentric arc for coinciding with said arcuate opening and being arcuately spaced apart at equal angular intervals equal to the intervals of said add scale, and a colored background strip for one half of said depressions in order to indicate when the direction of rotation of said disk should be reversed, said arcuate opening extending circumferentially an angular amount such that a single add-scale angular interval of rotation of said disk may be added at either end of said add scale by manipulation using the end one of said depressions opposite the one or the nine of said add scale, all whereby said disk may be manipulated using said depressions in conjunction with said multiply and add scales plus said colored strip and in accordance with said modulo-ten formula.