Patent GB-153622-A (GB)
Title: Additions to and improvements in and relating to course recording instruments
Filed: 1919-07-03
Abstract: 153,622. Glover, W. J., and Booth, C. H. July 3, 1919. Course-recording apparatus. - A travelling course recorder is provided with means for marking every mile or other distance, for marking the time and for setting to different scale charts. The instrument as shown in Fig. 1 may be provided with three elements, Fig. 6, comprising a milled wheel 7 rotated by means of a worm gear driven by a pawl 14 and ratchet 13 through a bevel gear 11, 12. An electro-magnet 15, receiving its impulses from the Forbes log, operates each pawl 14 by means of a forked armature engaging a ring connected to the pawl shaft. The planes of the milled wheels are changed in accordance with the master-compass charges by the usual transmitter driving a step-by-step motor 1 which rotates the elements through the gear box 4. This gearing comprises a pinion 17, mounted on an arm 16 fixed on the shaft 2 of the motor, meshing with internally toothed wheels 18, 19, the wheel 18 being fixed and having 179 teeth, whereas the wheel 19 has 180 teeth and meshes externally with the wheels 3 of the elements so that for one revolution of the shaft 2 the wheel 19 moves forward one tooth, i.e. a ratio of 180 to 1. Any desired gear can be obtained similarly. At every mile the electro-magnet 27 is energized and rotates the marking device 21 by means of a fork 24 in the lever 25 engaging a helical guide 23. At every quarter hour the electro-magnet 45 depresses the time - marking wheel 34 on to the chart. This wheel 34 is oriented in agreement with the milled wheels 7, by means of a worm gear 35 driven by a toothed wheel 20 in mesh with the wheel 19, consequently the time is always marked on side of the traced course. The timemarking wheel 34 is advanced by means of a pawl 39 at every fourth depression, this pawl 39 being held out of engagement with the ratchet 41, which is in one with the time-marking wheel 34, by the use of an idler ratchet 40 having shallower teeth except at every fourth tooth when the two ratchets move together. The electromagnet 45 is energized by the time contact, Fig. 12. A star wheel 60 on the minute spindle 59 raises a weighted lever 61 carrying a contact 64 in the form of a right-angle with the inside of the bend covered with insulating material. On the downward motion, the contact 64 makes on the front face of the specially shaped contact 66 but on the upward motion the inside of the bend of the contact 64 makes on the back face of the contact 66 which is also covered with insulating material. Fig. 16 shows a device to enable the instrument to be used on different scales, for example 8, 4, and 2 miles per inch and its function is to give 1, 2, or 4 impulses to the electromagnet 15 per impulse of the Forbes log. An electro-magnet 68 in parallel with the electromagnet 15 is energized through a contact 67 similar to that shown in Fig. 12 and rotates a ratchet wheel 77. This wheel 77 is provided with pegs of different lengths arranged in the order long, short, medium, short, which depress the upper arm of the contact 15<a> when they press on the wedge 81 of insulating material. The contacts 15<a> and 67 are in parallel and the former can be moved as a whole so that the wedge 81 engages only the long pegs, the long and medium pegs, or all the pegs. On an impulse from the log the contact 67 will be broken and the peg wheel moved forward which may close the contact 15<a>; the electro-magnet 68 will then be energized for the duration of the impulse; if the contact 15<a> is not made, the contact 67 will rise again and the process repeated until the contact 15<a> is closed so that the electro-magnet 68 and therefore the electro-magnet 15 will receive a number of impulses per impulse from the log. The wheel 77 may have 20 teeth and fixed to it may be a wheel 78 with one tooth engaging a wheel 79 with 20 teeth. The wheel 79 is provided with 4 pegs at 90 degrees in the same order as before and operating similarly a contact 27<a> by which the mile-marking electro-magnet 27 is energized at every lundred impulses from the log independently of the scale setting, since if the number of impulses in the electro-magnets 15 and 68 is doubled the wheel 79 has to rotate through twice the angle before the electro-magnet 27 is energized. The instrument is provided with electromagnets 53 which hold it down on an iron plate 54 on which the chart is placed.