Patent GB-236013-A (GB)
Title: Improvements in or relating to means for operating camera shutters at a distance
IPC: G03B9/58
Filed: 1924-05-17
Abstract: 236,013. Leong, C. H. May 17, 1924. Shutters.-An appliance for operating a camera shutter from a distance by releasing or slightly tugging and releasing a length of string, tape or the like, comprises a bobbin for taking up the string, a motor, preferably clockwork, to rotate the bobbin, and means operated or released by the motor for releasing the camera shutter. The appliance may be so adjusted that the exposure is made only after all or a prearranged portion of the string is drawn in. In the case of an instantaneous exposure device built as part of the camera or shutter, the motor moves a member which presses on the shutter trigger to release it when the string is being wound in or a catch is moved to release a device such as a spring lever arm which pushes the shutter trigger. An appliance providing for both time and instantaneous exposures embodying auxiliary mechanism released by the motor is shown in Fig. 6. A catch q which normally abuts against a projection o of a cam m containing a spring n in the position shown is withdrawn by an element moved by the motor when the string is released, whereupon the cam moves in clockwise direction causing the shutter actuating slide 3 to be depressed and released through the agency of magnifying levers y. By means of a lever 12 in conjunction with a pawl q<1> and dash pot p the rotating cam projection o is temporarily retained by the pawl to increase the exposure interval, which is regulated by selectively setting the lever 12. In a modification, a crank and connecting rod replace the cam and a spring controlled lever is interposed between the crank and the catch q. Shutters which involve two pressing and releasing motions require the provision of two cams or of two projections on the cam. Fig. 8 shows means for operating an antinous release by a device separate from the camera, the release plunger 1 being pressed by the cup-like head of a slide 3. The plunger barrel 2 is held by a clip 4, the position of which may be adjusted by thumb nuts 7 when the string is drawn out a short distance in order to retard the opening of the shutter until the string has been drawn in by the motor to the same distance. A device for operating a pneumatic shutter release may comprise two roughened surfaces hinged together between which the bulb is placed, the surfaces being kept apart against the action of a spring by a catch which is released by the motor for an exposure. A clip may hold the string when pulled out, or a device for holding the string until released by a slight tug may be employed. On the string being pulled out a ratchet wheel 30, Figs. 10, 11, fixed to the bobbin spindle or any fast moving shaft of the motor, is retained by a pawl 33 until a lever 35 is moved by the operator into the position shown in Fig. 11, whereupon a slight tug at the string releases the pawl 33. The string which may be kept at a suitable tension by means of guide members, and which may be marked to serve as a measure of length, preferably has a tassel or kite or parachute-like construction at its free end. A distance meter may be embodied on the machine. To prevent the bobbin from rotating if the string breaks the bobbin spindle may be arranged close to the mainspring so that when the spring uncoils beyond a certain extent its outermost coil presses on the bobbin spindle and stops the motor. The appliance made as a. separate article may be fitted with clips or screws for ready attachment to the camera, a tripod, or a tree of the like.