GB191422929A - Improvements in "Range Finders". - Google Patents

Abstract

22,929. Kennedy, A. M. Nov. 23. Range-finders.-Range-finding apparatus comprises a sighting-device at one or each end of a base controlling one or both of two electric currents which pass through separate coils of a differential galvanometer or like indicating-instrument which reads directly in ranges. The apparatus is so constructed that the currents are proportional to the series of the angles at one sighting-device and at the object respectively, in the triangle determined by the sighting-devices and the object sighted, and are thus in the same ratio as the range from that sighting-device and the length of the base. As shown in Fig. 1, the coils 8, 9 of the galvanometer are in circuit respectively with a rotatable coil 11 and a fixed coil 10 forming armatures in magnetic fields produced by coils 3, 4 wound on cores 1, 2 and connected in series with an alternating or pulsating current generator 12. The cores 1, 2-are rotatable and are connected by a belt or chain 15 or otherwise so that in all angular positions their fields are at right-angles. The sighting-devices are secured respectively to the core 1 and the armature 11 as indicated by the arrows 13, 14. In the modification shown in Fig. 3, the coils 43, 44 of the meter are connected in parallel with variable resistances c, d, a, b respectively in a circuit containing a battery 37, the positions of the sighting- devices 32, 33 controlling the variable resistances. The sighting-device 32 is mounted at right-angles to a conductor 30, which is secured at right-angles to an insulating-strip 28, and these parts may be rotated as a whole about a pivot 20. Parallel insulating-strips 16, 18 of equal length are pivoted at the ends of the strip 28, and wires 24, 25 of relatively high resistance are stretched between them and alternatively contact with the conductor 30 to provide one of the variable resistances in the circuit. At the other end of the base, a similar arrangement of strips, wires, and conductor is provided, in which, however, the conductor 31 and strip 29 are fixed. The sighting-device 33 is mounted on the strip 17, and a strip 34 equal in length to the strip 16 is fixed at right-angles to the strip 17 and is connected to the strip 16 by cords &c. 35, 36, so that the strips 16, 17 are at rightangles to each other in all positions. In both these constructions, when the sighting-devices are directed to any particular object, the range of the object from the sighting-device on the left of the figure is indicated by the galvanometer. A depression type of apparatus is described in which the construction shown in Fig. 1 is modified by the omission of the sighting-device 14, the coils 4, 11, and the core 2, and the coils 8 are connected in series with the generator 12 and the coils 3.