Patent GB-191001053-A (GB)
Title: Improvements in Means for Indicating, Locating and Predicting the Position, Direction and Velocity of a Distant Object.
Inventor: BARR ARCHIBALD
Filed: 1910-01-15
Granted: 1911-01-16
Abstract: 1053. Barr, A., and Stroud, W. Jan. 15. Range - keepers. -Means for indicating, locating, and predicting the position, direction, and velocity of a distant objectcomprise in combination a positionindicator and a record member, to one of which is imparted a movement the resultant of two motions, one corresponding to the change of bearing and the other proportional to the change of distance of the object; or one motion may be imparted to the indicator and the complementary motion to produce the resultant movement to the record member. In one form of apparatus, shown in Fig. 1, a collimator tube G, carrying a lamp D and lens H to produce a luminous image on a table I in a position corresponding to that of the object observed, has imparted to it the distance motion by the range-receiver R' rotating the threaded shaft J, upon which a nut carrying the collimator is mounted, and the bearing motion by the bearings-receiver R<2>, which rotates, by means of a worm and worm wheel, the pivoted frame carrying the collimator &c. about the axis A A. Alternatively, a pencil or indicating-point may replace the collimator. The lens only of the collimator may receive the distance motion. In other forms, there is no mechanical connexion with the bearings-receiver, but as in the form shown in Fig. 4, the frame is turned by means of a handle L by an observer in accordance with the movements of the bearingsreceiver R<2>, the distance movement of the image of the lamp D being produced by the range-receiver R<1> rotating the mirror N, from which the rays from the lamp D are reflected on to the table I, after passing through the lens M and being reflected from the vertical mirrors K, K<1> through the lens M<1>. Unless the table is turned equally with the spindle A of the bearings - receiver R<2> which carries the mirror K, the mirror K<1> carried by the frame is not parallel with the mirror K, and two images of the lamp are projected upon the table. Fig. 6 shows mechanical means for indicating whether the frame is turned conformably with the bearings-indicator R<2>, which is geared with the element V<1> of a differential gear, the frame turned by means of the handle L being geared with the element V<3> of the differential gear, the intermediate element V<2> of which carries a drum X with a mark Y to be kept opposite a fixed mark Z by the handle L being turned by the observer. Another form is described'in which the moment of inertia of the rotating frame is made small to reduce the work required of the bearings-receivers, of which there are two connected by worm gearing with the frame, and in which the only work performed by the rangereceiver is the turning of a mirror to deflect the rays from the lamp producing the image. A transparent scale for reading from the plotted positions the predicted range and the amount of deflexion to be allowed is shown in Fig. 11. This scale is pivoted by means of the ring C<2> upon a stud. on the record table in line with the axis upon which the frame rotates. The range of the point q<3> predicted from the plotted points q<1>, q<2> can be read off from one of the radial scales shown radiating from the centre of rotation of the scale. Deflexion is read off by observing upon which of the deflexion lines ruled at the side of each range scale the point q<2> falls. Means for finding the absolute velocity and direction of motion of the object are shown in Fig. 12 and comprise a slit of light or a straight-filament electric lamp B<2> producing an image upon the table by means of the movable lens H<1>. The effective length of the slit or filament is adjustable according to the speed of the observer's vessel, and is parallel with its keel so that the line projected upon the table represents the velocity of the observer's ship. One end of the luminous line is brought over a plotted point, and the line joining the other end of the luminous line to the next plotted point represents the absolute velocity of the object. Specifications 4404/06, [Class 92, Ordnance &c.], 4422/06, 15,256/06, and 29,450/06, [all in Class 40, Electric telegraphs &c.], and 13,306/07, [Class 92, Ordnance &c.], are referred to.