Patent:US1163392
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Aus der Patentschrift GB191413073
"Proportional calculators.-In apparatus having two main graduated stationary arms A secured at an angle, preferably a right-angle, the adjustable members consist of a third side or hypoteneuse member B, pivoted to one end A<5> of one of the graduated members, and of two sliders C, E adapted for adjustment upon the graduated stationary arms and provided with clamping-screws C<1>, E<1>. A rectangular strut member D, having limbs D<4>, D<5> passing freely through apertures in the sliders, constitutes a means for correlating the positions of the sliders with the angle of the hypoteneuse member, for which purpose the apex D<1> of the strut may be clamped in a lengthways slot of the member B. One of the sliders may be dispensed with, and the corresponding reading taken at the edge of the limb of the strut member. ..."
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Foto
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Modell nach der Patentschrift
Multiplikation und Division mithilfe des Strahlensatzes.