Patent GB-829902-A (GB)
Title: Improvements in and relating to adjustment of photographic cameras
IPC: G03B7/00
Filed: 1956-03-05
Abstract: 829,902. Photographic cameras with coupled exposure meters. VOIGTLANDER A. G. March 5, 1956 [March 4, 1955; March 23, 1955; July 5, 1955], No. 6899/56. Class 98(1) [Also in Group XL(b)] A camera is provided with adjusting elements for the stop value, the exposure time, and the speed of the sensitive material. Stop values or exposure times may be adjusted manually at will and the non-manually adjusted control is then set mechanically and automatically by a photo electric exposure meter to give the correct exposure having regard to the other two adjustments. A non-automatic position may be provided in which both stop value and exposure time may be set manually. In a first embodiment a separate control element is set to control whether a manual adjusting member is connected to the stop setting or the exposure setting element and to connect the other element to the exposure meter mechanism. Exposure time setting ring 1 and stop adjusting ring 8 are, in this, mounted rotatably about the shutter casing. Behind them is a further ring 15 having a stepped aperture 29 cut in it and behind that manual adjusting member 32. Determination as to whether ring 15 is to be connected to ring 1 or ring 8 (or neither) and manually adjusting member 32 to the remaining ring (or also to neither) is by means of control element 60 rotatable to three positions 90 degrees apart. In the first of these pin 72 on the disc 60 is in its uppermost position and holds slide 25 at the top of its travel. This slide by means of fork 24 places detent-retained pivoted arm 20 in a position so that pin 23 engages in recess 10 and couples rings 8 and 15 together. Projection 13 on lever 11 on ring 8 is, at the same time held clear of notch 40 formed in a projecting part 39 on manually adjusting member 32. Projection 7, however, on a lever 5 on the ring 1 engages in this notch so that ring 1 is coupled to member 32 and can be adjusted by it in accordance with the values indicated on scale 25b opposite to pointer 37. In the second position of the control element pin 72 is in position 72a and the slide 25 is thus moved downwards to cause pin 23 to move to its mid-position and out of notch 10. In this position both the rings 1 and 8 are available for ordinary manual adjustment and the automatic exposure control disconnected. In the final position of control 60, pin 72 reaches position 72b and the slide 25 is moved to its lowest position. Pin 23 is moved downwards to engage notch 4 and couple ring 1 with ring 15. At the same time projection 13 is allowed to drop into notch 40 to couple ring 8 and member 32. The downward movement of slide 25 carries the scale 25b on its lower part away from pointer 37 and uncovers a scale 38a calibrated in stop values. As the changeover to be effected by control 60 can only be made when the pin 23 and the notches 4 and 10 are aligned, locking levers 65 and 66 are provided whose upper ends engage in slots 61 in control disc 60 and prevent its rotation except when the lower ends are engaged by projections 69 and 70 on ring 15 and member 32 respectively. The final angular position of ring 15 is determined by the photo-electric exposure meter, the position of member 32 which carries a shaped aperture 33 for the purpose, and control 43. This latter is adjustable to the speed of the sensitive material and is preferably arranged so that it can only be reached when the camera is being loaded. It effects a movement of slide 50 relative to carrier 41 by means of pinion 48 and rack 49. Carrier 41 slides on rod 42 and takes up a position in correspondence with the setting of control 60 and the positioning of member 32. Its movement is effected by means of pin 74 on disc 60 and lever 77 acted on by spring 79. In the uppermost position of slide 25 carrier 41 is urged upwardly by spring 79 so that pin 58 makes contact with the upper edge of aperture 33 in member 32. The exposure meter mechanism is effective with the row of steps on the upper side of opening 29 on ring 15. When slide 25 and carrier 41 are in their mid-position (in which spring 79 extends directly over the pivot 80 of lever 77) the exposure meter mechanism is ineffective and does not contact either of the stepped sides of opening 29. With both in their lower positions the mechanism co-operates with the steps on the lower side of the opening. As shown in Fig. 4 the meter movement is supported on the bent over upper end of slide 50 and the movable arm 53 of the meter shaft moves lever 55 mounted in strong bearings to a position corresponding to the intensity of the light received. The end 57 of this lever contacts one of the steps on the side of opening 29 to limit the movement of ring 15 under the influence of spring 16 in the setting period. Opening 33 in member 32 co-operates with the end of pin 58 on carrier 41 so that the automatic setting takes into account the manual adjustment made. In another embodiment (Figs. 6 and 7, not shown) the control disc 60 and adjusting member 32 are modified so that only one manual adjustment is needed. To this end disc 60 carries a scale extending from the largest exposure time to the shortest, then having a part where both stop and exposure times are manually adjustable, and finally a further scale reading from the largest to the smallest aperture. The disc is coupled by link-work to move the equivalent of member 32, which is not provided with a handle or scale, from one end of its travel to the other and back again whilst pins similar to 72 and 74 of Fig. 1 effect corresponding changeovers. The other parts of the arrangement are substantially the same as in the previous embodiment except that locking levers are omitted. Rotation of disc 60 sets one factor manually and automatically connects the other control to the photo-electric meter except in the manual position when rings 1 and 8 can be set in the usual way. The Specification discloses with respect to Figs. 8 to 18 (all not shown) ways of coupling the meter movement shaft to an arm so constructed and mounted that the impact of a stepped or equivalent member against it will not damage the meter. In these, the arm is linked to the meter in the manner generally indicated in Fig. 4. It is made rigid in the plane at right angles to the axis of rotation but resilient perpendicular to that plane. Stationary supports are provided just clear of the free travel path of the arm and the stepped member mounted so that its impact with the arm deflects the latter into contact with the supports which are robust enough to withstand the shock. Figs. 5, 19 and 20 (not shown) of the drawings indicate how the embodiments may be incorporated in the bodies of cameras.