Patent GB-696484-A (GB)
Title: Improvements in focusing hoods for photographic cameras
IPC: G03B13/20
Filed: 1950-05-19
Abstract: 696,484. Photographic cameras. HEIDECKE, R., [trading as FRANKE & HEIDECKE]. May 19, 1950 [March 3, 1949], No. 12616/50. Class 98 (i). A focusing hood for photographic cameras of the kind provided with focusing view-finders has direct-vision view-finding apertures in the front and rear walls of the hood, a panel normally closing the front aperture and movable to an open position out of the direct vision viewfinding path, and also a magnifier lens and an auxiliary mirror for viewing the ground glass screen of the focusing view-finding system, the panel being resiliently urged towards the aperture-closing position and the mirror being pivotally mounted on the panel and being provided with two abutments, one of which is held locked in the opened position of the panel and the other is engageable with the panel under the resilient panel pressure so as thereby to lock the panel in the open position and secure the mirror in the required angular position relatively to the magnifier lens and screen. As shown, the front wall 3 of the hood is hinged at 4 to the frame 1 carrying the ground glass screen 2 on which an image of the scene to be photographed is thrown by means of a mirror mounted below. The rear wall 11 of the hood is hinged at 10 to the frame 1, and the cover-plate 6, carrying the magnifier 9. for inspecting the screen 2, is hinged at 5 to the front wall 3. The plate 6 is normally held horizontally against a stop 8 by a spring 7. The direct-vision viewfinder is formed by the apertures 14, 12 in the front and rear walls respectively, and the aperture 14 is normally closed by a panel 15 hinged at 16 and pressed by the spring 17 to the upright position. A lever 19 also hinged at 16 abuts against a stop 32 on the auxiliary mirror carrier 33 and is hinged to a strut 18 carrying a pin 20 slidable in the slot 21. The pin 24 of the strut 22 hinged to the plate 6 at 23 is also slidable in the slot 21. On pressing the panel 15 down to the position shown, the pin 20 slides downwardly in the slot 21 and pulls the strut 22 down to swing down the plate 6 to the position shown in which it closes the top of the focusing hood, the pin 20 then entering the notch 25 and locking the struts together. The lever 19 turns the auxiliary mirror carrier 33 clockwise against the action of the spring 30 until the lug 34 engages the panel 15, the auxiliary mirror 28 then reflecting part of the image on the screen 2 into the magnifier 13, thus enabling both viewing through the direct-vision view-finder and inspection of the ground glass screen 2 to be made practically simultaneously. The lock. may be released by pushing down the coverplate 6 or by pushing the front wall 3 to rock the lever 19 through the link 18 until it is stopped by the abutment 27. In a modification, the abutment 27 may be omitted and the upper end of the rear wall 11 constructed to engage the rear end of the cover-plate 6 as the front wall is swung rearwardly, the plate 6 being thus caused to swing downwardly to release the lock. The focusing hood may be folded together in the normal way. The side walls of the hood may be joined to the frame 1 or to the front or back walls.