Inventors:
John Freedom - Tinley Park IL
Thomas Freedom - Palos Park IL
International Classification:
G06C 300
Abstract:
There is disclosed a calculator adapted to determine optimum fertility time periods for a female, formed by a first scale divided into 365 equal units, each unit assigned a day for each month of a full calendar year, a second scale positioned in operative relation to the first scale, the second scale including a first information segment formed by a series of 15 equal units, each unit representing a day in a menstrual cycle and ranging between 20 such days in a cycle and 35 days in a cycle, and a second information segment positioned a predetermined distance forward of the first information segment, the second information segment comprising the optimum fertility indicator segment and constructed by measuring a time period two days prior to and two days subsequent to the day of ovulation, the optimum fertility indicator segment constructed in the form of a box having a total of eight equal units from end to end, the center unit representing the point of ovulation, and the two markings measured therefrom each being spaced two equal units forward and rearward therefrom, the units being measured identically to the units formed on the first scale, whereby the optimum fertility period may be determined by the user thereof by placing the known number of days in a female's menstrual cycle from the second scale in registry with the date when the last menstrual cycle commenced as measured on the first scale, thereby to bring into registry the second information segment on the second scale with a certain time period as read from the first scale thereby to determine the time period of maximum fertility, and also showing the time period of non-fertility.