Patent GB-190108360-A (GB)
Title: Improvements in or relating to Photographic Shutters.
Inventor: BOULT ALFRED JULIUS
Filed: 1901-04-23
Granted: 1901-09-21
Abstract: 8360. Boult, A. J., [Bausch & Lomb Optical Co.]. April 23. Shutters. - Relates to photographic shutters which are arranged for making time, instantaneous, and bulb exposures. The casing for the shutter, Figs. 1 and 2, is formed of a back section 2 for attachment to the camera front, and a front section 1 to which is attached the lens. In a recess in the part 1 is an iris diaphragm, held in place by a clip 10 and comprising a ring 7, leaves or blades 70, and an annular rotary plate 8 having an index finger 9. The leaves 70 are provided with pins co-operating with the rings, so that by relative movement of the rings the size of the aperture can be adjusted. A spring-controlled lever 11, pivoted on the face of the part 1, rests at one end on a movable cylinder 13 forming part of the bulb or pneumatic engine, and is provided with a pin 14 extending through an opening in the casing for the purpose of controlling the operating-mechanism, The shutter members are supported upon a plate 5, Figs. 4 and 6, and preferably consist of pivoted wings 16 provided with projecting tongues 18 extending between pins 19 projecting through a slot in the plate and connected to an actuating-lever 21. This lever is actuated by a pivoted master lever 26, which is operated by a lever 32, the levers all being controlled by springs. The lever 26 is made of spring material, such as brass or steel, and so shaped at the parts 25 &c., which act upon pins 24 and 34 on the levers 21 and 32, that latch connections, acting only in one direction, are formed between these levers. The lever 32 carries a lug 35 adapted to engage a projection 36 on a controlling-member 37, which carries an arm 40 having an inclined time stop 41 and an arm 42 having a bolt stop 43. These stops may be brought into the path of a lug on the master lever 26, during the making of time or bulb exposures. The lever 32 is operated by the pin 14 on the lever 11, and the member 37 is spring-controlled and its position is adjusted by means of a pin 45 secured to an index arm 46, Fig. 1, cooperating with characters indicating time, instantaneous, and bulb exposures respectively. When the member 37 is in the position for obtaining instantaneous exposures, the stops 41, 43 are out of the path of the lug on the lever 32, and, by operating this lever, the lever 26 is moved without operating the shutter, and is returned by its spring to operate the lever 21, and thereby open and close the shatter. When it is desired to make a time exposure, the pin 45 is moved so that the stop 41 may lie in the path of the lug, as shown in Fig. 6, so that, when the lever 32 sets and releases the lever 26, the latter engages the member 21, and, as the lever 32 only partially returns to its normal position due to its engagement with the projection 36, the movement brings the time stop into engagement with the lug, and holds it there with the shutter open. A second movement of the lever 32 is required to release the parts. In making a bulb exposure, the stop 43 engages the lug, and the shutter is held open so long as the lever 32 is prevented from returning by the action of the lever 11, which is controlled by the bulb.