GB531996A - Improvements in or relating to light measuring devices - Google Patents

Abstract

531,996. Photo-electric photographic exposure meters. SANGAMO WESTON, Ltd. Aug. 10, 1939, No. 23132. Convention date, Jan. 14. [Class 40 (iii)] [Also in Group XXV] In a photo-electric photographic exposure meter provided with means for altering the proportion of available light allowed to fall on the lightsensitive cell, these means are adapted to cause the automatic exposure of the corresponding scale of the measuring instrument. As shown, a barrier-layer cell 2 is exposed through a multiple compartment 4 and a multiple lens plate 3 as described in Specification 435,335, [Group XX], and a perforated shutter 11 is hinged at 13 and can be moved over the lens plate as shown in full lines or out of the way as shown in dotted lines. The shutter is held in the full line position by a spring bolt 14, and in the dotted line position by the knob 15 of the same bolt. A scale plate 20 carries two scales corresponding to the two positions of the shutter 11, and is slidably mounted below a window plate 8 over which moves the pointer 7 of the moving coil 6 of the measuring instrument, which has a fixed permanent magnet 5. The scale plate 20 is connected by a lever 25 to a sliding rod 28 ; and a spring 23 urges the scale plate outward and makes the rod 28 bear against the heel of the shutter 11. Hence when the shutter is in the closed position, the outer scale is exposed at the window in the plate 8 ; and when the shutter is in the open position, the inner scale is exposed.