Improvements in or relating to binoculars, monoculars, telescopes and like viewing instruments

摘要

406,336. Binoculars &c. ; anglemeasuring instruments. OWEN, H. E. L., 73, Perham Road, West Kensington, and OWEN, R. E. L., 18, Wilton Crescent, Wimbledon, both in London. Aug. 23, 1932, No. 23606. [Classes 97 (i) and 97 (ii).] A binocular &c. telescope is provided with a magnetic compass and a periscope for projecting into the eyepiece a horizontal image of the horizontal portion of the compass rim that is opposite the upper reflector of the periscope when the compass is held horizontally for determining the magnetic bearing of a distant object. A clinometer may also be provided by which the elevation of the observed object may be read off in the eyepiece. As shown, a binocular telescope 1 is provided with a periscope tube 2 having an enlarged head 4 to which is attached a housing 5 containing the upper reflecting prism 10 of the periscope. The housing 5 has an extension 6 in which is rotatably mounted a tube 8 extending from the box 9 of a liquid magnetic compass. The compass card has a vertical rim 9b bearing graduations of which an image is projected by the periscope system into the eyepiece 7 so as to be seen as a horizontal image. The lower reflector of the periscope comprises a compound prism 11, 12, the prism 11 having a reflecting surface 11a, Fig. 2, inclined at 45‹ to the horizontal, and the prism 12 having a reflecting surface 12a lying in a vertical plane inclined at 45‹ to the exit surface of the prism. The compass card may be graduated on its flat surface to enable bearings to be read directly when the cover 9d is raised. To enable angles of inclination to be read, the housing 5 with the compass can be removed from the tube 2 and replaced by a clinometer comprising a weighted pendulum 18, Fig. 4, provided with transparent scale 18a adjacent a window 16 ; a fixed wire 19 forms a zero line. The lens 3 and prisms 11, 12 project an image of the clinometer scale into the eyepiece. Alternatively each of the two telescopes of a pair of binoculars may be provided with a fitting so that an image of the compass graduations is seen in one eyepiece and an image of the clinometer scale in the other.