Patent GB-208128-A (GB)
Abstract: 208,128. Goerz Optische Anstalt Akt.- Ges., Akciovß Spolecnost K. P. Goerz Opticky ustav, C. P. Dec. 9, 1922, [Convention date]. Addition to 207,184. Range-finders.-Apparatus for predetermining the azimuth angle and the angle of sight of a point moving in a straight line with constant velocity in a horizontal plane at a known height, at a given time after the observation comprises a sighting device and means whereby the path of the point is registered by real or virtual projection as a line on a given scale on a horizontal drawing surface. The point in space moving through the points 0, 1, 2 at a known height H over the point of intersection P of the vertical and horizontal axes of rotation of a sighting device, has its projections 0<11>, 1<11>, 2<11> marked on a reduced scale on a plane surface passing through the point P<11>, bv means of a pencil 11, Fig. 3. The apparatus is mounted on a tripod 39 and levelled by screws, and arranged to rotate about a vertical axis 40, which is fixed. A bevel wheel 4, keyed to the pivot 40 is engaged by a smaller bevel wheel 6 rotated by the handLe 8 to turn the slide 3<a>, and a worm mounted on this bevel wheel 4 is utilized to rotate the curve plate 5 into any direction. The pencil 11 is mounted in a. guide 9 and traversed along the slide 3a by the screw 21 rotated by the handle 22. The height of the pivot 14 of slotted links 117 is adjusted by a screwed sleeve 12 in accordance with the height of the point in space, this height being indicated on a dial 13. The links 17 are pivoted in the axis of the pivot 40 and connected by a parallelogram linkage to the sighting device 20 so that the line of sight X-X is always parallel to the links 17. In place of a pencil 11 a pin 11<a>, Fig. 6, engaging a hollow spindle 26a, may be used. This spindle 26<a> is arranged in a ruler fitted with multiplying gear 26, 27, 28 whereby the pin 36 is traversed at such a multiple of the rate of the pin 11<a>, that at the end of the observed period, the pin 36 will indicate the position of the point in space at the predetermined instant. When the pin 11<a> is in the position 0<1> and in the hollow spindle 26a it is depressed to fix the ruler 23 to the drawing surface by the pin 35 and subsequent movement of the pin 11<a> automatically sets the ruler 23 in the correct direction. The pin 36 is turned over on its pivot to abut against the edge 37a of the curve plate 37 at the point 2<1>, Fig. 5. The readings for determining the necessary setting for the gun and fuze are made from the curves on the plate by a radial ruler 38. This ruler 38 moves over the curve plate 37 and is fitted with two aiming marks 38<a>, 38<b>. The edge of the plate, having been brought into register with the point 2' corresponding with the final position of the pin 36, the mark 38<a> is set to the same point and the ruler 38 then rotated over the plate 37 to read off on the appropriate curves by means of the marks 38a, 38<b> the angle of direction, the time of flight, the fuse setting and the deflection due to rifling. In a modification the plate 37 may be constructed as a plane mirror and the point in space viewed by reflection, the tracing point being also viewed along the same line of sight.