Patent GB-191408312-A (GB)
Title: Improvements in Telemeters.
Filed: 1914-04-02
Granted: 1915-06-24
Abstract: 8312. Zeiss, C., [Firm of]. April 23, 1913, [Convention date]. Range-finders; micrometer systems. -Telemeters are so grouped together in a system that, each being a singleobserver instrument and provided with a setting device, a joint indicating- device is so moved on the operation of the setting- devices, which may be mechanically joined together, that a mean value is given. As shown in Fig. 1, the movements of the Rochonprisms 5 of the two telemeters shown operate the scale 6 and index 7 of a joint indicator. In the modification shown in Fig. 2, two coincidence instruments are included in the same casing 8 with oculars facing in opposite directions. The deviation prisms 13 move, for measuring, in the same direction, and each operates an indicator, while also acting through racks 21, on a pinion 23, the arbor of which is attached to slides carrying a sca!e moving against an index to give a mean value of the individual readings. In a further modification, somewhat similar to the last, setting of the deviation prisms, which rotate in the same direction, rotates the Amici prisms 46, Fig. 6. These prisms form part of an optical system forming an image of a mask 44 in the plane of a scale in the ocular which occurs behind the last reflecting-prism 43 of the system. The joint scale is, in this case, four times as open as that of the individual instruments. Fig. 10 shows an arrangement for getting a mean reading from three telemeters by means of a long - distance indicator. A rotating field is formed at each telemeter, which acts as a transmitting point, by two pairs of stationary coils 61, 62 on an iron core 60, these being supplied with two phase current from lines 57, 58 and a neutral line 59. The lines are also connected to stationary coils 66, 67 at a common receiving-station, while a movable coil 68 carrying an indicator 70, at this station has connected to it, in parallel, pairs of coils 63 at the three transmitting points, these coils being carried on wheels 64 which are rotated during the setting of the instruments. In a further modification, shown in Fig. 13, in which two telemeters are used in one casing, means are provided for adjusting the two instruments mutually before reading. Reading of the individual telemeters is given by pointers 93 reading on scales on the adjusting - heads 92, and the joint indication is given by means of an index 104 on a window 103 reading on a scale 102 on a box 101, on which is mounted the bevel - wheel 99 adapted to be driven by differential gearing from both setting movements of the prisms 90, 91. For adjustment before taking a reading, the tube 75 of the upper telemeter is rotated till the aperture 83 faces the prism 107, Figs. 13 and 14, and the prisms 85 are turned into the positions shown in dotted lines, and the prisms 90, 91 are set for infinity. An image of an external object produced by the objective 105, Fig. 14, is then thrown into the instrument, split by the separating system 81 and transmitted as the two images of an object at infinity to the lower telemeter. When coincidence in this instrument is effected, the index 93 is, if necessary, adjusted to an infinity reading and, similarly, for the joint reading.