GB431911A - Improvements in or relating to surveying instruments - Google Patents

Abstract

431,911. Surveying instruments. NAAMLOOZE VENNOOTSCHAP MACHINERIEEN-EN APPARATEN FABRIEKEN MEAF, (formerly NAAMLOOZE VENNOOTSCHAP MACHINERIEEN-EN APPARATEN FABRIEKEN), 30, Croeselaan, Utrecht, Holland. Dec. 24, 1934, No. 37009. Convention date, Jan. 17. [Classes 97 (i) and 97 (ii)] A sighting-telescope, an adjustable mirror adapted to reflect the sun's rays along a path parallel to the axis of the telescope, and a lamp provided with means for aligning it with the telescope are combined into a single instrument. As shown, a lamp casing 1, provided with a light source 3 of small size and a reflector 4 is mounted on an adjustable base 2 and forms a support for the sighting telescope 5 which is in two portions arranged to fit together so that the abutting ends form an annular collar 17. The latter is inserted in an annular recess in a bracket on the casing 1 and secured by a wedge 21. The cross wires of the telescope are illuminated at night by light from the lamp 3 passing through an aperture 18 in the casing 1, a slide 19 for regulating the intensity, and a small prismatic rod 6 mounted in the telescope wall. Means for accurately determining the position relatively to the reflector 4 to which the lamp 3 must be adjusted, consist of two small optical systems 9 disposed in the lamp casing 1 so that the angle subtended at the light source 3 is substantially 90‹ and adapted to reflect images of the light source adjacent each other on cross marks on the matt side of a prism 10. The systems 9, Fig. 3, each comprise a plano-convex lens 11, silvered on the flat side, embedded in a bowl-shaped member 12, and covered with a diaphragm 13. Fine adjustment of the reflector 11 is effected by rotating annular-shaped wedges 14 inserted between the member 12 and its seat. A pressure screw 15 is used for clamping. The adjustable mirror 7 for reflecting the sun's rays and a frame 8 carrying cross wires are mounted on the eyepiece and objective ends of the telescope respectively by conical pins disposed in threaded bushes. One of the bushes is bored eccentrically so that a lateral displacement of the conical pin is effected when the bush is screwed up or down. The instrument is adjustable about vertical and horizontal axes and the mirror 7 and lamp 3 are for the purpose of enabling the point at which the instrument is situated to be located from a distant observation station. The lamp 3 may be made to transmit intermittent flashes by a shutter controlled by a Bowden wire.