GB574046A - Improvements in or connected with rangefinders and like optical observation instruments - Google Patents

Abstract

574,046. Range - finders. BARR & STROUD, Ltd., and FOSTER, C. Dec. 4, 1939, No. 31374. [Class 97 (i)] The eyepiece (or eyepieces) of a range-finder having a self-contained base is carried by an extension system enabling the observer to make observation with the back of his head towards the base casing; the base casing may be rotatable about its axis, and the eyepiece (or eyepieces) may be movable relative to the casing so that their displacement due to rotation of the casing may be reduced. As shown in Figs. 2 and 3, an eyepiece 8 is carried on a mounting 7 rotatable about the axis 12 of a tube 6 extending from a base casing A rotatable in bearings 11 ; additional prisms 9 and lenses 10 are provided. The mounting 7 may be turned about the axis 12, as indicated in Fig. 3, when the base casing is turned, so that the eyepiece remains within reach of the observer. Each eyepiece of a stereoscopic range-finder may be similarly and separately carried, the mountings 7 being extensible to permit maintenance of the interocular distance ; alternatively, the eyepieces may be mounted on a bridge connecting the two tubes 6 and be immovable relative to the casing A. Figs. 9 and 10 show a construation wherein the eyepiece is rotatable round an axis 21 parallel to the axis of the base casing A, and on a forward extension 19 from a fixed tube D within which the casing A is rotatable ; an arm 23 on the eyepiece mounting 20, connected by a link 24 to a bracket 25 on the casing A, causes automatic movements of the eyepiece when the casing A is rotated. Stereoscopic range-finders may have two links and arms for separated eyepieces, or one link for eyepieces on a bridge connection.