GB534450A - Improvements in or relating to photographic shutters - Google Patents

Abstract

534,450. Photographic shutters. KODAK, Ltd. March 1, 1940, No. 3847. Convention date, March 22, 1939. [Class 98 (i)] In a photographic shutter comprising an apertured shutter blade 12 moved by a spring 20 to uncover an aperture 15 in the shutter plate 11, a member 43 holds the blade during tensioning and is then moved to release it by means carried by manually-operable tensioning means 16, the member 43 also moving into the path of the blade to prevent rebound thereof after completion of the exposure. In the form shown, inward movement of the operating knob 26 causes a spring blade 27 to engage alternately shoulders 32, 33 formed on a plate secured to the frame-like member 16, which is thereby rocked in alternate directions about its pivot 18, so tensioning the blade-actuating spring 20 to move the blade in alternate directions to make successive exposures. From the position of rest shown, depression of the knob 26 causes the spring blade 27 to engage the shoulder 32, so rotating the member 16 clockwise. In the early part of the movement, a cam surface 47 on the member 16 raises the spring 43, but allows it to return and again to engage a shoulder 40 on the blade 12 -before the blade is turned by the spring. When the frame 16 has turned to tension the spring fully a second cam 47 on it raises the spring 43 to release the blade 12, which then moves clockwise to make the exposure. The spring then engages behind a second shoulder 41 on the blade, preventing the blade rebounding. For giving time exposures a bell-crank lever 51 is loosely mounted on the shutter blade pivot, and is engaged at 54, 55 by a lug 21 on the shutter blade being thereby turned until the end 60 of one arm engages a time stop button 59, which arrests the movement with the shutter blade in the open position. For instantaneous exposures, the button 59 is turned so that a cut-away portion 62 allows the end 60 of the lever to pass.