GB1300980A - Coital timing device - Google Patents

Abstract

1300980 Calculating apparatus CAMBRIDGE RESEARCH & DEVELOPMENT GROUP 20 Nov 1970 [21 Nov 1969] 55369/70 Heading G4B A device for calculating the fertile period of a woman, from the predetermined shortest and longest menstural cycles, and indicating an optimum coitus schedule to maximize the chance of conception, comprises two relatively movable scales, the first scale 34 being divided up into calendar months and days, the second scale 42 having a series of longest cycle markings 54 associated with each different shortest cycle marking 52 and a coitus schedule indicator 46 divided up into coitus and coitus abstention increments (i.e. periods of time in which coitus is and is not recommended respectively) 48, 50, which are preferably of different colours, for each group of similar shortest cycle markings. An initial abstention increment 114 may also be provided. The relative positions of the schedule indicator and cycle markings are dependent on the numerical value of the shortest cycle. A start of cycle indicator 56 is also provided on the second scale. Associated with the second scale is a further stationary indicator (58), (Fig. 6, not shown) with coitus and coitus abstention indicators 62, 64 for increasing the length of the coitus schedule when the difference between the shortest and longest cycles is greater than 3 days. In a preferred embodiment the scales are provided on moving belts running between parallel spaced rollers located within a common housing (Figs. 1 to 3, not shown). The second belt is transparent and both belts are viewable through a window 24. To use the device the second scale 42 is aligned so that the desired shortest and longest cycle markings appear in windows 26, 28. The first, calendar, scale is then moved so that the first day of the menstral cycle is aligned with the indicator 56. The recommended coitus schedule for maximizing the chance of conception is indicated by the increments 48, 50, 62, 64 and 114. A slidable day of the week indicator (Fig. 7, not shown) may be provided as well as fixed markings 94, 96 on the window 24 to facilitate the determination of menstrual cycle lengths. The device may be provided with interior lumination powered by batteries, such as an electroluminescent panel, to assist the reading of the scales.