Patent GB-769189-A (GB)
Title: Monocular photographic reflex camera
IPC: G03B19/12
Filed: 1955-05-31
Abstract: 769,189. Photographic reflex cameras. DECKEL, H., and DECKEL, F. W. May 31, 1955 [June 2, 1954], No. 15558/55. Class 98(1) In a single-lens reflex camera, a separate power source is provided for bringing the mirror from viewing position to exposure position, and the shutter has means cooperating with the mirror-actuating mechanism in such a manner that the mechanism is released for operation by the power'source is provided for bringing the the action of the camera shutter. As shown in Fig. 1. the between-lens shutter mechanism is contained in a housing 10. A toothed setting disc 16 is fast on a setting spindle 14 journalled in the casing 10, and a main driving element 18 is loosely mounted on the spindle 14 below the setting-disc 16. A driving spring 20 is mounted so as to be tensioned when the main driving element 18 is rotated anticlockwise, by a projection on the disc 16 co-operating with a lug 28 on the main driving element. The shutter blades 30, mounted within the shutter casing 10, are pivoted to a rotatable ring 34 and have guide slots 36 engaged by driving pin 38 rotated on a rotatable blade ring 40. A projection 42 of the blade ring 40 co-operates with the main driving element 18 to be actuated thereby when the blades are to be opened for an exposure. The opening of the blades for viewing purposes, on the other hand, is effected by rotating the ring 34 by. means of its radial arm 44 against action of a spring 46. The iris diaphragm comprises blades 52 pivoted on fixed pivots 54, and having pins 56 working in guide slots 58 of a diaphragm setting ,ring 60, which is rotatable by its projecting radial arm 62 to vary the diaphragm aperture. Ring 62 is urged by a spring 64 towards a lug 66 (Fig. 2) on a stop preselector ring 68. Ring 68 is set by means of an arm 70 moving over a scale of stop values 72. A control element in the form of a ring 76 is rotatably mounted in the shutter casing 10, surrounding the front lens tube 78. A radial arm 80 of control ring 76 can when rotated clockwise, engage the arms 62 and 44 of the elements 60 and 34 respectively. The control ring 76 is, however, normally held by action of a spring 84 in a rest position wherein the arm 80 rests against the face 86 of an opening 82 in the shutter casing. The setting-disc 16 meshes with teeth 88 formed on a sector of the control ring 76, so that the control ring 76 is rotated clockwise by operation of the shutter setting mechanism, and is held in set position by a pawl 92 engaging behind a lug 93 on the control ring 76. Control ring 76 also carries a pin 96 engaging a lug 98 on a toothed segment 100, which is pivoted at 102 in the shutter casing 10 and spring- urged clockwise. A lug 106 on the segment presses against a lug 108 on a locking lever 110 pivoted at 112 in the shutter casing 10. Locking lever 110 also has a projection 118 co-operating with a cam 120 on the control ring '76, and a locking nose 122 which can engage behind a lug 124 on the main driving element 18. The element 18 is controlled from setting ring rotatably fitted 'to the front of the shutter in order to vary the time of exposure. A spring 136 acts on a segment fast with a spindle 130 which is connected to the reflecting mirror in such a way that the action of the spring tends to raise the mirror out of the path of the rays entering through the lens. A cam 138, driven by the film winding mechanism, acts on the segment 134 in such a manner that, when the film is wound, the mirror is brought down into viewing position. The segment is then held in position by a lug 142 on a spring-loaded double-armed pawl 142. With the parts in the set position shown in Fig. 1, the setting spindle 14 is rotated anti-clockwise by the shutter setting means, rotating the setting disc 16 and the driving element 18 in the same direction. This movement also rotates the control ring 76, so that the arm 80 first actuates the arm 62 of the setting element 60 of the diaphragm stop, and afterwards the arm 44 of the ring 34, so that in the set position the iris diaphragm and the shutter blades are both brought to the open position. Control ring 76 is then held by the locking pawl 92 engaging its shoulder 93. The pin 96 on the control ring 76 locks the segment 100 enabling the locking lever 110 to turn anti-clockwise under spring action so that its locking nose 122 engages the main driving element 18. Its projection 118 is now in contact with the periphery of the control'ring 76. The shutter release is now effected by a trigger actuating a release element 94, which actuates pawl 92 to release the control ring 76. This allows the control ring to return under spring action, also allowing the iris diaphragm and shutter blades to close. The arm 80 of the ring 76 then engages the double pawl 142, rocking it so that lug 144 releases the segment 134. Spring 136 then rocks the segment about spindle 130, so that the mirror is brought up into its inoperative position. During the movement of the mirror, the segment 134 blocks movement of the arm 80. Only when the movement of the mirror has been completed can the ring 76 continue its movement. In the second part of the movement of the control ring 76, its cam 120 turns locking lever 110 clockwise and' releases it'from engagement with the main driving element 18. The driving element 18, rotating under action of its spring, engages the arm 42 of the blade ring 40 to cause the shutter blades 30 to open for an exposure. Meanwhile, the diaphragm blades 52 remain at their preselected setting. Continued movement of the driving element 18 causes the shutter blades to close again. The mirror actuating mechanism can also be connected with any other moving element of the between-lens shutter: A modification is described in which the segment 134 does not directly engage the control ring 76, but with an intermediate element fixed on the end of the setting spindle 14.