GB523292A - Improvements in or relating to range finders - Google Patents

Abstract

523,292. Range-finders. KODAK, Ltd. April 14, 1939, No. 11333. Convention date, April 14, 1938. [Classes 97 (i) and 98 (i)] , The two beams entering a short base rangefinder pass through negative lenses producing virtual images which are re-imaged by collective lenses to form a combined image in the plane of a collective field lens, the combined image being viewed by a telescope; the range-finder may be combined with a camera and be adjusted simultaneously with the focussing adjustment of the camera lens, and may be simultaneously adjusted for parallax. As shown in Fig. 2, the beams from negative lenses 16, 17 at the ends of a base are reflected by surfaces 11, 12 to objectives 18, 19 producing images in a plane near a field lens 22 placed near the exit face of a prism 13 doubly reflecting part of the beam from the lens 16. The images are viewed by a telescope comprising an objective 20 having its axis parallel to the base and an eye-piece 21 having its axis perpendicular to the base, a reflector 14 being provided between them. Coincidence of the images is effected by moving the lens 17 in its plane by means of a sliding bar 29 operated through an extension 32 engaged by one arm 27 of a lever on a pivot 26. The lever may have an arm 25 engaged by a raised ring 24 on the camera objective, the range-finder being thus adjusted simultaneously with focussing adjustment of the objective. A third arm 28 of the lever carries a range-indicating scale 34 visible in the eye-piece with a frame 35 embracing the image produced by the objective 20. Parallax adjustment of the image in the frame 35 is effected by means of an arm 36 which is pivoted at 37, carries the objective 20, and is moved vertically by engagement with a lug 39 on the lever arm 25. Fig. 3 shows a modification in which negative and positive lenses 40, and prisms 41 ... 44, produce images in the plane of a field lens 45, the images being viewed by a telescope comprising objective lenses 53 and an eye-piece 54. A ring 49 on the camera objective operates, through a lever 50 and an arm 46 on a pivot 47, to turn the prism 42 and effect coincidence of the images. The arm 46 carries a rearward projection 57 carrying a scale'56 visible through an opening in a frame 55 enclosing the viewed image. The projection 57 also carries an ear 62 having an inclined edge engaging a spring-pressed rod 58 mounted on a pivot 59; the rod 58 carries one objective lens 53, and adjusts it for the parallax between the lenses 40 and the camera objective. Specification 129,043, [Class 97 (i)], is referred to.