Fecha de publicación: 06/11/1913 Fuente: WIPO "pollen" 2497. Pollen, A. H., and Isherwood, H. Feb. 4. Range-keepers.-Relates to means for giving mechanically a reading of the changing range of a moving target when the initial bearing, range, speed, and course of the target are known and the course and speed of the observing ship. If BO, CO, Fig. 2, represent the velocities of the observing ship and of the target respectively so that BC represents the velocity of the ship both in magnitude and direction with respect to the target then a carriage R travelling along BC with a velocity proportional to BC will represent the travel of the ship. The bar OZ is set to the bearing of the target, and the bar RL, Fig. 5, is set so as to be parallel to OZ and, initially, so that it passes through the centre of a drum T connected to a drum G as shown. The carriage R is spring-pressed towards C, Fig. 6, but constrained by a rod K carrying a roller L, which engages a fixed bar BM and only allows motion of the carriage to the left in proportion to its own constant travel outwards under the influence of clock-work. A pointer on the drum T indicates the range as the drum is rotated. The readings may be transmitted to the gun.