Patent GB-191223349-A (GB)
Title: Apparatus for Automatically Plotting the Courses of a Ship and a Moving Target.
Inventor: POLLEN ARTHUR HUNGERFORD
Filed: 1912-10-12
Granted: 1913-10-09
Abstract: 23,349. Pollen, A. H., and Isherwood, H. Oct. 12. Range-finders. - Consists of a device for automatically plotting the courses of a ship and a moving target. The paper is laid on a table 1 and is gripped between rollers 2, 3 and 7, 8. The latter pair of rollers are carried by a bracket 18 depending from a carriage 22 slidablv mounted on the fixed arm 4, at the extremity of which is the fixed pencil 39 for plotting the course of the target, the pencil 6 for plotting the course of the ship being carried by the carriage 22. Assuming the ship to be fixed, the change of range is plotted by moving the paper bodily over the table parallel to the line 6-39. For this purpose the carriages 10, 22 carrying the pairs of rollers 2, 3 and 7, 8 can be slidden at the same speed by means of the shafts 13, 14 driven by the shaft 15, Fig. 2, and having screw-threads of identical pitch engaging with nuts on the carriages 22, 10. The shaft 15 is driven from a transmitter geared to the range-finder &c. To plot the changes of bearing of the target, the paper can be rotated about the pencil 6. The carriage 10 and arms 18 are rotatable about vertical axes and are driven at the same speed by worm gearing 24, 23 and 20, 19 respectively, the shafts 25, 21 being driven by the shaft 27, which is rotated by a transmitting-gear at a rate corresponding to the rate of change of bearing as obtained from the range-clock &c. To plot the ship's motion, the paper is moved by the rollers 2, 3 beneath the pencil 6. The rollers are rotated in the same direction to represent the ship's speed by a shaft 47, which is driven at the ship's speed by a motor 101 through suitable gearing. The shaft 47 drives a worm mounted on the carriage 10, and the worm drives a wormwheel 45 on the shaft 46 carrying a bevel-wheel 44 engaging the bevel-wheel 43 fixed to the shaft 42. The bevel-wheels 104, 105 are also fixed to the shaft 42 and drive the wheels 108, 109 through idle bevels carried by the forks 106, 107; the wheels 108, 109 carry the rollers 2, 3, which are thus rotated at the same speed. To rotate the paper round the pencil 6 to represent changes in the ship's course, the rollers 2, 3 can be rotated in opposite directions at the same speed. A shaft 63 is gyroscopically controlled so that its rotation is proportional to the change in the course, and drives a bevel-wheel 61 through the worm gear 62. The wheel 61 drives the forks 106, 107 in opposite directions through the wheels 59, 60, and causes the idle wheels to drive the wheels 108, 109 and consequently the rollers 2, 3 at the same speed in opposite directions. A modification of the device for driving the rollers 2, 3 is described, in which the rollers are prevented from rotating on their axes when the frame 10 is rotated for change of bearing. To mark the plot at equal intervals of time, the pencils 6, 39 are caused to describe small circles on the paper at equal intervals. The pencils are eccentrically mounted on axes about which they are rotated by the shaft 72 and gearing 68, 69, the shaft 72 being instantaneously rotated at the required intervals. To obtain the angle between the course of the target and that of the ship, a dial 34 is driven from the shaft 21 and an arm 37 is read against it: the arm 37 moves with a scale 38 set to coincide with the course of the target. The angle between the arm 18 and the line of sight represents the bearing of the target, and can be read on the dial 32 carried by the arm 18 against the pointer 33 carried by the carriage 22.