GB340013A - Improvements in or relating to calculating devices particularly applicable to mean speed indicators - Google Patents

Abstract

340,013. Wendling, H. Sept. 12, 1929. Logarithmic calculators.-Apparatus for calculating products and quotients of simple factors or of factors raised to a power incorporates two toothed cams interengaging to give a logarithmic conversion. The apparatus shown in Fig. 2 for calculating a quotient, in this case mean speed, comprises a cam H1 driven from a flexible drive R<1>, whose angular rotation is proportional to the magnitude of one factor, through the successive 10 to 1 gearing trains D1, J1 &c. the wheels D1, &c. gearing with wheels F1 &c., fast on the shaft E and toothed over <1>/6th of their circumference, the toothing on each of these wheels being displaced angularly by that amount with respect to that in the preceding wheel, and the circumference of the wheels F1 &c. being 5.4 times that of the wheels D1 &c., in order that, the factor varying from 1 to 10, the wheel D1 makes <9>/10 of a turn engaging all the teeth on the wheel F1 and rotating the shaft E 1/6th of a turn, and the factor varying from 10 to 100, the wheel D2 makes <9>/10ths of a turn and the shaft E 1/6th of a turn and so on. The cam H1 is rotated from the shaft E through the gear train G multiplying the movement by six and engages with the toothed cam H1<1>, giving a logarithmic conversion. The cam H1 makes a complete revolution corresponding to the completion of each decimal place effected by the wheels F1, F2 in succession. The cams H2, H2<1> are driven from a shaft, rotating through an angle proportional to the other factor, through gearing similar to that driving the cams H1 and H1<1>. The rotations of the cams H1<1>, H2' are transferred to a differential with sun wheels V1, V2, planet wheels W, W<1>, and frame S giving a rotation equal to half the difference of the rotation of the cams H1<1>, H2<1> which is thus a measure of the quotient of the factors. The simultaneous gearing of the cams H1, and H1<1> at the two points h and h<1>, Fig. 1, is facilitated by a pivoted sector I urged by the spring i<1> against an abutment i on the cam H1. The return to zero is effected by causing the shaft E to complete the rotation commenced, a lag of <1>/54th of a turn of the shaft being provided (the wheel F1 carrying supplementary teeth on <1>/54th of its circumference) to eliminate the initial error due to the logarithm of 0 not being mechanically translatable.