GB633510A - Improvements in and relating to range finders for photographic cameras - Google Patents

Abstract

633,510. Photographic camera range-finders. KALART CO., Inc. June 25, 1947, No. 16781. Convention date, Nov. 10, 1941. [Classes 97 (i) and 98 (i)] A range-finder attachable to a photographic camera contains a lever system operated by the focusing movements of the camera lens to drive a wedge which operates the pivotal reflector of the range-finder system, the velocity ratio of the lever and wedge system being variable. One form. is shown with cover removed in Fig. 14, the operating elements located behind, and mainly carried on, the plate 72 in that figure being shown in Fig. 18. The range-finder has the usual light-entry and viewing windows, a semi-reflecting mirror 119 and a mirror 114 pivoted on trunnion screws 108 and operated by an arm formed in two parts ; one, 112, being stiff, the other, 106, somewhat flexible and adjustable relatively to it by a screw 113 and carrying a pin 103 projecting through the plate 72. A spindle 53 projecting through the range-finder casing carries at its outer end an arm which engages a projection on the camera bed adjustable for focusing. The arm is held in contact with the projection by the spring 67 acting on the arm 66 carried inside the range-finder casing on the spindle 53. The projection on the camera bed is eccentric and rotatable for adjustment purposes. Movement of the lever 66 is transmitted to a lever 76, pivoted at 75, through the rounded portion 84 of a leaf-spring 83 secured to a member 82 adjustable along the lever. The spring 84 permits some overtravel of the arm 66 caused by the movement of the external arm when the camera is folded. In an alternative construction this overtravel is provided by a spring-loaded pin and slot device in the external arm. This device also provides the relative adjustment of range-finder and focusing movements. The lower end 86 of the lever 76 bears against a member 88, pivoted at 89, in contact with which is held, by a spring 93. a wedge member 92 which bears on an adjusting screw 97 and operates the pin 103 through the inclined surface 102. The screw 97 is carried on a plate 98 adjustable along the casing wall and held in place thereon by a wire spring 101. The adjustments provided in the range-finder permit its use with camera lenses of different focal lengths.