Patent GB-138321-A (GB)
Title: Improvements in method and apparatus for navigating vessels and aircraft
Filed: 1920-01-05
Abstract: 138,321. Bates, L. T. Jan. 25, 1919, [Convention date]. Mariners' compasses. - Apparatus for navigating vessels and aircraft on a predetermined irregular course includes means for changing the position of the lubber line automatically in accordance with the course to be steered. When the lubber line is on the rim of the compass 3, the latter is mounted on a platform 7, Fig. 1, carried by a shaft 8 which passes down through a fixed bracket 16, and has a pinion 17, Fig. 3, gearing with a rack 18. The outer end of the rack is secured by a link 20 to a lever 21 mounted on a rocking- shaft 22. This shaft carries levers 27, 29 which may be clamped thereto by a screw 30. The lever 29 has a pointer 34 and is adjusted with reference to lever 27 by a bolt 32 passing through a slot 31 in the former. The lower end of the lever 27 has an extension plate 35 freely mounted in vertical slots. In the plate is a pin 39 upon which is a roller which moves in a cam groove 41 of the course controlling cam 42. The pin 39 is constrained to move horizontally by a guide 44, the latter being extended to form a pointer 45 for the initial setting of the cam 42. The cam is attached to a plate'50 which is rotated by an electric motor through worm and worm gear 55, 56, splined shaft 57, and friction disk 58. The speed of the plate 50 can be varied by adjusting the disk 58 through a lever 61 on a shaft 60 controlled by a hand-lever outside the pedestal 1. The speed of the motor is maintained constant'by clock mechanism which cuts in or out resistances in the armature or field. The motor shaft 54 drives by worm gearing a disk 66 having three insulated sections 67, 68, 69, and on the shaft of the disk is a hand 70 driven by clock mechanism. If the motor speeds up and drives the disk 66 faster than the hand 70, the latter contacts with the section 69 and the field resistance is reduced. If the motor slows up, the hand 70 contacts with section 68 and the armature resistance is reduced. The clock is stopped and started simultaneously with the motor. As the cam revolves, the compass is moved, and the ship is steered by the helmsman keeping the lubber line in position with regard to a fixed mark 4. For ordinary steering, the platform 7 is locked by a pin 11, which is operated by a rod 12 passing through the pedestal 1 and rack-and-pinion gearing 11, 13. The cam disk may have more than one cam groove with pivoted automatic points for guiding the roller. The disk is provided at its periphery with contact blocks opposite each position of change of direction which co-act with a fixed brush in a circuit containing an audible or visible signalling device, so that the change in course is communicated as desired. The contact blocks may be made of different numbers of segments so that variation in the form of signal denotes the particular course started. In order to obtain a correct setting of the cam, the groove is arranged with a positioned extension for the initial entrance of the roller to the groove, and the cam is set with respect to its driving disk by pins. In a modification, the cam member is clamped between the driving disk and an outer rim. Instead of worm gearing operated by the oscillating lever for moving the compass base 7, one of a series of pulleys on the base shaft 8 is rotated by a cord passing round the pulleys and fixed at its ends to the oscillating lever and an extension thereof.