Patent GB-678063-A (GB)
Title: Apparatus for the continuous cinematic solution of the ratio between the integrals of two independent variables
IPC: G01P11/00
Filed: 1950-07-26
Abstract: 678,063. Quotient and average-speed indicators. PERROTTI, F., and VALDIVIESO, M. July 26, 1950 [July 27, 1949], No. 18726/50. Classes 106 (iii) and 106 (iv). Apparatus for the continuous solution of the ratio between the integrals of two independent variables as the difference of their logarithms, comprises a differential device operated through gearing by the two meters of the variables, the driving element of each of which consists of a plane logarithmic spiral profile on the surface of a disc guiding an oscillating arm, and is characterized in that the axes of rotation of the driving elements and of the differential device are arranged in alignment and are supported by separable and distinct frames capable of being easily coupled to form a single unit. In one embodiment a clock 0, Fig. 5, drives through a shaft a and friction coupling 2, 3, a disc 5 having a logarithmic spiral cut in its under-surface, which spiral is followed by a projection 6 on an arm 7, and the motion transmitted to a sector 12 driving one of the sun wheels 16 of a differential gear. A worm 10, driven, e.g., by movement of a vehicle, drives through another friction coupling, a second disc 5<SP>1</SP> having a logarithmic spiral which is followed by an arm 7<SP>1</SP> and a sector 12<SP>1</SP> which drives the other sun-wheel 161 of the differential gear. The planet-wheel 15, which travels round the axis c by an amount representing the difference between the two logarithms, moves a graduated dial 17 past an index F to indicate, e.g. average speed. Manually-operable knobs 21, 21<SP>1</SP> provide for resetting of the logarithmically-grooved discs. The sections A, B, C are adapted to be assembled as completed units, the shafts 8, 8<SP>1</SP>, 18, 18<SP>1</SP> being formed by a number of separate elements connected by sliding couplings (not shown). In another embodiment a worm 209, Fig. 7, driven in proportion to distance travelled, turns a worm-wheel 208 carrying a pair of pinions 211, 211<SP>1</SP> engaging respectively with gearwheels 212, 212<SP>1</SP>, the numbers of teeth in which differ by one so as to provide a high reduction gear. The gear 212 is held while the apparatus is in operation, but can be manually rotated through gearing 215, 216, 217, 219 for zeroizing purposes. The spirally-grooved disc 213 which turns with the gear 212<SP>1</SP> co-operates with a projection 226 on a sector 223 which drives, through a pinion 224, a shaft 225 carrying a transparent dial 222. A second spirallygrooved disc 233, driven through gearing from a clock mechanism 238, co-operates with a projection 231 on a sector 229 which drives, through a pinion 228 and sleeve 227, a pointer 230 for indicating against the graduations of the dial 222. The fixed casing may also be graduated. Zeroization of the disc 233 is performed by pushing a pinion 235 out of mesh with a pinion 236 and rotating a knob 243 to drive the disc back to zero. The logarithmic spirals are preferably continued to form circular grooves at both their innermost and outermost limits to avoid locking of the mechanism.