GB406309A - Improvements in apparatus for indicating the quotient or product of two quantities - Google Patents

Abstract

406,309. Calculating-apparatus; speedometers; indicating-apparatus; weighing- apparatus. PEARSON, J. L., 2, Bank Road, Billingham, Stockton-on-Tees. Aug. 17, 1932, No. 23043. [Classes 106 (i), 106 (iii), and 106 (iv).] Apparatus for indicating the product or quotient of two factors comprises two cylindrical or right-conical surfaces carrying logarithmic curves, one of the surfaces at least being moved by some exterior mechanism, the curves co-operating with a fixed reading edge in such a manner that the required result can be read off one of them. The embodiment described is used for determining the mean speed of a vehicle. An inner cylinder A is rotated in accordance with distance travelled and has around its edge a scale B of miles. If an axial line is taken on the surface of the cylinder then the logarithms of distances are marked off on this line in such a manner that the last mark has the same value as the point with which it coincides on the scale B. This is repeated for a number of axial lines all round the cylinder and the corresponding points are joined to form curves C which are marked with figures representing speeds. An outer transparent cylinder F is rotated by clockwork and has a logarithmic curve H related to a time scale G. A second curve J, similar to the curve H but for a different range, is also marked on the cylinder F in a colour different from that of the curve H. The cylinder A is placed inside the cylinder F in a casing M and the curve C which happens to be intersected by the curve H (or J) at a fixed reading edge O indicates the required speed. An ordinary speedometer is observed through an aperture V, the distance scale B through an aperture R, the time scale through an aperture S and actual time through a window T. The shafts P and Q of the drums are connected to their driving means through clutches and the scales may be illuminated by a lamp placed inside the cylinders. The apparatus is stated to be applicable to fuel-consumption meters, watt meters, altimeters, and price-and-yardage and price-and-weight machines.