Patent GB-218290-A (GB)
Abstract: 218,290. Bertin, C. F. J. M. June 30, 1923, [Convention date]. Course-recording apparatus.-A device for recording the course of a vessel comprises means for summing up the north-south and east-west components of predetermined lengths of course and which are proportional to the sines and cosines of the successive compass readings or angles of the head of the vessel for each distance travelled. The compass effects the movement of two members with insulated surfaces each of which controls one or other of a pair of electric motors that are rotated an amount proportional to the angles, the movement being transmitted to a corresponding integrating mechanism and recording member. As shown diagrammatically in Fig. 2, the movable member is constituted by a cylinder on which is formed a curve and the symmetrical curve with respect to the section of the cylinder perpendicular to its axis, the curve serving to separate two electrically conducting surfaces 1, 2. Co-operating withthe surfaces is a set of brushes 5, 6 mounted on a slide 7 carried by a screwed rod 8 adapted to be actuated through a differential gear 9 by one or other of a pair of motors D<1>, D<2>. The motors. which are shown as series motors with two fields, are adapted to rotate in either direction according as they receive current through the leads 14<1>. 15<1>, 14<11>, 15" from a distributor comprising three commutators 10, 10<1>, 10". The motors are also connected through a differential gear 16 to the shaft 17 of the registering mechanism. Rotation of the cylinder to vary the value of x effects the rotation of the commutators in such a manner that they make one half revolution for each successive value of x whereby the motor circuits are controlled to impart a movement to the shaft 17 proportional to f(x0)+f(x1)+f(x2)+&c. where x0, x1, x2 &c. are the successive values of x. As described the apparatus comprises two arrangements A, B, Fig. 5, of cylinders, brushes and motors, similar to that above set forth, for obtaining the components of the course in the north-south and east-west directions and with means for combining these movements to actuate a single recording point 53, Fig. 6, The cylinders 40, 40<1>, which are adapted to be rctated by a device under the control of the compass are formed of two conducting surfaces separated by sections 42, 42<1>, these sections being arranged at an angle of 90‹ and representing ellipses whose ordinates are proportional to the sine and cosine of the course angle respectively. A log or clockwork regulated by the speed of the vessel is adapted to indicate or signal the completion of each predetermined unit distance of course covered and at the same time to actuate commutators similar to those above referred to so as to displace the brushes distances proportional to the resolved components of the course. The successive movements, which are communicated to the registering shafts 17<a>, 17<b> are transmitted through reducing gears 45<a>, 45<b> to shafts 46<a>, 46<b> arranged as shown in Fig. 6, to operate the recording point 53. Mileage counters 55<a>, 55<b> and transmitting devices 56<a>, 56<b> may be provided the latter being adapted to control a distant recording device. To compensate for variations in latitude when recording on a chart with a non-uniform scale such as a Mercator chart the arrangement shown in Fig. 7, is adopted. The pairs of brushes 5<a>, 6<a>, &c. are each mounted on a rod 65a which is pivoted to the slide 7a and has a roller 68<a> disposed in guides 66<a>. The roller 68a engages a cam surface 64a adapted to be set by gearing 62, 63, through a differential 60 from the shaft 17<c> of a counter for determining the latitude, the latitude of departure being set by a hand crank 61. The Specification as open to inspection under Sect. 91 (3) (a) comprises also means for obtaining the area of a closed curve as above described and shown in Fig. 2. In a modification, Fig. 4 (Cancelled) the brushes 20, 21 may be arranged in contact with plain surfaces 22, 23 the conducting portions of which are bounded by a curve 24, 25, 26. The brushes may be adjusted relatively by means of a squared shaft which acts as a guide for the slide and carries a screw on which is mounted a nut forming a support for one of the brushes. This subject-matter does not appear in the Specification as accepted.