GB190103172A - Improvements in Range Finders or Telemeters. - Google Patents

Abstract

3172. Barr, A., and Stroud, W. Feb. 14. Range-finders.-Relates to improvements on the invention described in Specifications No. 9520, A.D. 1888, and No. 13,507, A.D. 1893, which have for their object the elimination of errors due to bending of the frame. Fig. 3 shows diagrammatically one form. Light enters a compound prism D, which bends it three times at a right-angle and reflects it to a second prism D<1> combined with an .objective G. A third prism H reflects it finally to form an image for examination with an eye-piece E. Deviation by the prism C is prevented by a small prism K cemented on the back of C. The light entering the other end of the base of the range-finder does so by a prism A, similar to D, which reflects the light through the objective B to the prism C in the eye-piece E, as shown. Coincidence of the partial images may be effected by the adjustment of a refracting- prism R. By this disposition of the optical parts the two objectives G, B can be rigidly connected. The arrangement of the reflecting-prism may be modified in various ways. The beams from opposite ends of the telescope may be reflected through a common objective ; or separate telescopes may be used, rigidly connected. For use on board ship, a mounting may be employed which allows of adjustment in altitude and azimuth and which is fitted with a breast-rest.