Patent GB-147215-A (GB)
Title: Improvements in or relating to aerial navigation apparatus
IPC: G01C17/00
Filed: 1920-07-07
Abstract: 147,215. Werkstõtten f³r Prõcisions- Mechanik und Optik C. Bamberg. Nov. 20, 1917, [Convention date]. Addition to 147,194. Magnetic compasses. - Relates to navigating- apparatus for use on aircraft as described in the parent Specification, in which the observer indicates to the pilot the direction to be followed, and in which a directing-card 1, Fig. 2, is coupled to a rotary compass-box 14, Fig. 3, and a suitable indicating-device (not shown) for indicating when the aircraft is off the desired course. In place of the electrical contacts on the compass-box 14, two selenium cells 16, 17 are arranged on one side of the compass-card 15, whilst on the other side two sources of light 20 are located. Both the cells and the lights are fixed to the compass-box. When the desired course is being followed, the lamps 20 are covered by the card 15, but upon displacement of the compass box 14 by the vessel veering from its course or by readjustment of the director, one of the lamps is uncovered to illuminate one of the cells through which a current flows to actuate an indicating-device in view of the pilot. The directing-card 1 is rotated relative to the index 2 by a handle 3 through the gearing 4 and worm 6. By means of a flexible shaft 7 any angular movement imparted to the card 1 is also imparted to the compass box 14, through a worm 9 and worm-wheel 10, mounted upon the sleeve 11 carrying the yoke 13, which supports the compass box 14 in a cardan-like manner. Two selenium cells 16, 17 are arranged above the compass card 15, whilst two lamps 20 are mounted below it in cases 18, 19, in which are provided condensing lenses 21, by means of which a clearly-defined image is produced in the plane of the compass card 15. The compass card 15 has an incision 22, Fig. 4, extending over nearly one-half of its periphery, and is so formed that when the aircraft flies in the desired direction the radial edges 23 cover the sources of light 20. When the compass box 14 is displaced, one of the lamps 20 is uncovered, and one of the cells actuated to operate coloured lamps or some other indicating-device accessible to the pilot. The source of light 20 may be so arranged as to give an elongated image transverse to the edge 23, in order that a graduated exposure of light will result in a variable-current intensity through the selenium cell, and convey to the pilot the magnitude of the deviation. The Specification as open to inspection under Sect. 91 (3) (a) also describes an arrangement for transmitting the position of a compass card 25 to indicating-devices 33. Upon one side of the compass card 25 two sources of light 26, 27 are provided, whilst on the other side and rigidly connected to the sources of light, lies a rotary disk 29 carrying the selenium cells 30, 31, which are on a line parallel to the radial edges of the card 25. When the disk 29 is turned by steering the vessel, one of the lights is exposed, and the resulting current through the corresponding cell operates the motor 32 to rotate the disk 29 until both lights are again covered. The rotation of the motor 32 is transmitted synchronously to the motor 34 by a cylindrical switch 35, thus imparting any angular displacement of the disk 29 to the indicator 33. This subject-matter does not appear in the Specification as accepted.