Patent GB-581120-A (GB)
Title: Electrical methods of and apparatus for locating moving objects
IPC: G01S1/02
Filed: 1939-12-12
Abstract: 581,120. Linkwork. STANDARD TELEPHONES & CABLES, Ltd., JACOBSEN, B. B., and SECKER, B. Dec. 12, 1939, Nos. 32052/39 and 4289/40. [Class 80 (iii)] [Also in Groups XIX, XXXVI and XL] An apparatus is shown in Figs. 2 and 3 for predicting the future position of an object when its distances and velocities relative to three fixed points are known. Points A, B, C represent the fixed points, their distances apart being to any convenient scale. Universally jointed at these points are three extensible rods AP, BP, CP flexibly jointed at a point P such that it can occupy any position above the plane ABC. These extensible rods consist of two or more tubes telescoping within one another. They may be adjusted in length by being connected by a screw turned by a small motor, or they may be filled with a non-compressible fluid, their length being controlled by adjusting plungers. Alternatively, the tubes or rods may slide through A, B, C, their length being adjusted by rack and pinion. The extensible rods AP, BP, CP are provided with fixed length extensions AG, BH, CJ shown beneath the plane ABC. If the lengths of the rods AP, BP, CP be set to represent the distance of the object from the points represented by A, B, C, then P will, on the same scale, be the present position of the object. In order to determine the position of the object after an interval of time, the velocities are combined by means of the apparatus shown in Fig. 3. A1, B1, C1 represent the fixed points as before but translated laterally and A1 L1, B1 M1, C1 N1 similar extensible rods to AP, BP, CP. These rods have similar fixed length extensions A1 Gl, B1 H1, C1 J1, below the plane ABC, the lower ends of these extensions being connected by links hinged at each end to the similar points G, H, J. Fig. 2. Then A1 L1, B1 M1, C1 N1 intersect at a point P1 indicating the present position of the object relative to the points Al, B1, C1. A fixed length rod Q1 L2, P2 is mounted on a linkage attached to the rod A1 L1 so that it always lies parallel to A1 L1 by means of two parallel and equal links L2 D1, Q1 F1 hinged at L2, Ql, and sliding on the rod L1 A1. These links are constrained by two further links L1, U1, El, V1 hinged at L1, E1 so that the point L2 is constrained to move in a plane perpendicular to A1 L1 and passing through L1. Two other equal rods are attached in the same way to the rods B1, M1, C1, N1 and the three rods are universally jointed at P2. The extensible rods are set in accordance with the velocities and P2 is the scale position of the object relative to the points Al, B1, C1 at the time predicted. The flexible joints P1, P2 are constructed as shown in Fig. 4 in which two pieces of tubing AC, PB are rigidly joined perpendicularly to each other and take the cranked ends of the rods DE, FG, HJ, which are free to turn about the axis of the tubes, but held axially by set-screws &c. The upper ends of the rods are so cranked that no mutual interference is produced between them when the point P moves in any direction. The lower ends of the rods are free to slide and turn in ball joints E, G. J. The-apparatus may be combined with a machine for working out gun angles and fuse setting from position angles, distance, wind, velocities, &c. so as to supply directly settings for the guns.