Patent GB-191424715-A (GB)
Title: Improvements in or relating to Apparatus for Automatically Recording the Course of Ships.
Inventor: FORD HANNIBAL CHOATE
IPC: G01C17/00
Filed: 1914-12-29
Abstract: 24,715. Ford, H. C. Aug. 4, [Convention date]. Course-recording apparatus.-Apparatus for indicating a ship's course upon a chart, of the kind having a feed-roller adapted to be turned on its vertical axis in accordance with the ship's course and rotated about its own axis at a rate proportional to the speed of the ship, is provided with a compensating-connexion between the driving and turning means to prevent the feed-roller from being rotated upon its own axis by the directional driving-means; means are also provided for recording the position of a vessel under observation from the vessel containing the apparatus. A plan of the apparatus working on a chart is shown in Fig. 4, the apparatus being free to move on the chart in every direction, but being restrained from rotation about its own vertical axis by a parallel linkage system 48. The roller 13, Figs. 1 and 2, with serrated edge drives the roller apparatus over the chart, the serrations making a trace on the chart. This roller 13, which is mounted in a housing 34 at the end of a driven shaft 33, is made to rotate on its horizontal axis and to turn about its vertical axis by electric motors carried on the apparatus and respectively connected with a distance indicator, preferably driven from the ship's propeller shafts, and with a master compass. The roller 13 has a bevel-gear 26 driven from the two-faced gear 25, which is driven by the central shaft 23 connected to its motor by gearing including a differential gear combination. This differential gear is utilized to obtain a compensating movement through the connexion 19, 20 for the planetary action of the gear 25 round the gear 24 as the housing 34 is rotated in accordance with changes in the ship's course, the gear 20 being mounted on the shaft 33 to which the housing 34 is secured. The position of the target is indicated by means of a travelling carriage 51 provided with means for maintaining its position on the chart carried on a rod 36, to which angular motion corresponding to the movements of a telescope kept directed on the target is imparted by a motor actuated by a transmitter connected to the telescope, the gearing comprising a differential gear 43. Compensating movement for change of the course of the ship carrying the apparatus is communicated from the compass-controlled gear 20 through the pinion 49 fast to the gear 50 of the differential gear 43. The carriage 51 is traversed along the rod 36 a distance proportional to the range of the target by means of the threaded shaft 53 driven by a pinion 54 connected by gearing to a motor actuated by a rangetransmitter. The apparatus is also provided with means for recording time and the firing of guns. In a modified construction, the linkage 48 is omitted, three or more driving and directing rollers being used. Apparatus, shown in Figs. 9 and 10, is provided for giving the correct speed to the transmitter actuating the motor for traversing the apparatus at a speed corresponding to that of the ship, and for varying the scale of the recording movements of the apparatus on the chart. Motors 161 driven from the propeller shafts drive, through a differential gear, a speed cone 163 driving a friction roller 172 on the shaft of a transmitter 4 for actuating the speed driving-motor of the apparatus on the chart. The speed-cone and motors 161 are made adjustable with respect to the friction roller 172, in order to impart thereto the speed corresponding to the shaft revolutions and corrections for current &c., by being mounted on a threaded shaft 164, which can be turned by means of a head 168 to bring a indicator thread 178 carried by the speed-cone support into register with the appropriate point on the correction curves shown in the fixed plate 177 (which is shown displaced from its real position for convenience of illustration). The scale of reproducing movement on the chart is varied by means of the stepped gears 187, 189 transmitting movement to the speed and range transmitters 4, 11 respectively. The transmitters are both mounted on a plate 183 carried by a sliding rod 184, which can be turned by a knob 186 to disengage the gears and allow the sliding movement required to change gear to be effected.