Patent GB-191415600-A (GB)
Title: Improvements in or relating to Photographic Cameras.
Inventor: NIELL MAGNUS
IPC: G03B19/12
Filed: 1914-06-29
Granted: 1915-06-29
Abstract: 15,600. NiÚll, M. June 29. [Cognate Application, 24,174/14.] Focusing-devices.-Relates to a camera in which the image projected through the lens can be seen for the purpose of focusing, view-finding, &c. up to the moment of taking the photograph, through the back of the camera by reflection from a mirror arranged on the lens-carrying front. The viewing- aperture is in the form of an horizontal slot in the back of the camera above the sensitive surface, and the focal-plane shutter passes over it and is provided with apertures so arranged that the viewing- aperture is open when the shutter is set for taking a photograph, but is closed by the shutter while exposure of the sensitive surface takes place. The lever which controls the shutter releasing - mechanism first releases a slide carrying the lens supports so as to allow the lens to move back to bring the image from the plane of the viewing- surface to the plane of the sensitive surface ; it also controls mechanism which keeps out of action the means for holding the lens cap up, until the lens has been moved back into its focusing and view-finding position. A folding hood is arranged over the viewing-aperture and is constructed so that its form can be varied when it is desired to use the camera with the viewing-aperture vertical. The viewing-aperture A' is arranged in the back of the camera as shown in Fig. 4, the viewing- mirror E is mounted in supports E<1> tilted forward by springs on their pivot Ex, and the viewing- surface is arranged in front of the sensitive surface D, preferably on the back of the roller-blind shutter C. This shutter passes over rollers c', c<2>, c<3> arranged so that it passes over the viewing-aperture and sensitive surface in different planes. The shutter is provided with a narrow slot which, when the shutter is set to take a photograph, is in front of the viewing-aperture and also serves for instantaneous exposures. A second larger opening may be provided in the shutter for time exposures. The lens-carrying front F can be adjusted by a focusing-lever N, Fig. 5, mounted on a slide 0, which also carries the lever P that operates the shutterreleasing mechanism and normally engages a pin B<2> on the baseboard to hold the lens in its forward or viewing position. On operating the lever P, it is first freed from the pin B<2> to allow the slide O by spring action to carry the lens back to the rear or exposure position..The lens is provided with a spring-closed cap Q, Figs. 11 and 12, which, when the lens is in its forward position, can be held open by the engagement of a rod R with a projection Q<4> on its pivot Q<1>. As the lever P is operated, it pushes to one side a member S mounted as shown, but on its return, passes under and raises this member, so as to lift the rod R into the position shown in Fig. 12, to allow the cap Q to close and to prevent its being held open until the lens and its sliding support 0 have been pushed forward to allow the lever P to engage the catch pin B<2> and free the member S. The hood comprises two folding flaps I, Fig. 18, with spring binges tending to open them, and flexible light-tight parts I<2>, I<3> adapted to fold snugly inside the flaps. On the flap I<2> is hinged a disk J to form an eye-shade, and lugs or projections J<4> are provided to hold the flaps I in the partly closed positions shown, when it is desired to use the camera with the viewing- aperture A' vertical.