Patent GB-190915902-A (GB)
Title: Improvements in Photographic Cameras.
Inventor: LEVIE FRITZ
IPC: G03B9/28
Filed: 1909-07-07
Granted: 1910-07-07
Abstract: 15,902. Levie, F. July 7. Shutters, roller-blind; focusing-devices.-In a photographic shutter, the roller-blind curtain of the shutter engages the plate-carrier so that the latter is moved from and to the exposing position during the winding-up and running- down of the curtain respectively, and means are provided, in conjunction with the shutter mechanism, for simultaneously and automatically moving the screen into and out of focusing position to occupy this position alternately with the plate. A release and slitadjusting mechanism is also described for the shutter. In one modification, the screen d, Fig. 2, and plate frame b are mounted on a sliding frame e. The plate is inserted into the frame b from the side of the camera. In winding the shutter, a cross-bar n on the blind engages catches s, Fig. 3, on the frame e. The catches normally fit in a recess t in the frame e, and are mounted by slotted springs l which are engaged by pins o on the frame. As the bar n engages the catches s, the catches are raised to the extent of the slot and simultaneously projected forward, and the bar n engages recesses t in the catches and makes a light-tight joint with the plate-carrier. The exposure slit is above the plate-carrier when the bar n engages the frame e, and the focusing-aperture in the curtain is drawn into position with the focusing-screen d. On releasing the shutter, the plate moves down with the curtain into the focal plane. The bar n then disengages from the recess t and the shutter continues to run down to expose the plate. A modified construction of catch s<1> is shown in Fig. 7 for engaging the ends of a bar n which project from the sides of the curtain. In a modified apparatus, the focusing-screen is displaced rearwards. The screen d, Fig. 10, is mounted on arms 127 fastened to a spring spindle 121 which normally holds the screen d behind the focal plane, as shown in dotted lines. The lower part of the plate-carrier engages the arm 128 on the spindle 121 at the end of its upward motion, and brings the screen forward into the focal plane, in which position it is retained by the catch 123 engaging the arm 128. On actuating the release pin 122, the arm 128 is first released and the focusing-screen moves backwards. The upper end of the lever 123 then actuates the shutter release 124, and the plate is brought into the focal plane and exposed, as above described. In a further modification, the focusing-screen is connected by springs 44, Fig. 11, to a spring spindle 45 with an arm 50. The arm 50 is raised to bring the screen into the focal plane by a jointed rod 49 operated from the lower blind-roller 35 The roller 35 surrounds a screw 35<a>, Fig. 13, with a left-handed thread, on which is a nut 47 having a projection 46 engaging a slot in the drum, so that as the drum is wound up the nut 47 moves towards the left. At tho end of the movement, a lateral tooth 48 engages the jointed rod 49. The rod 49 is raised and engages the arm 50 to bring the screen into the focal plane. The upper end of the rod 49 is raised in front of the release lever 38. The winding and release mechanism comprises the winding-wheel 28, which carries the wheel 26 having a projection 27. The retaining pawl-lever 37 is normally disengaged from the wheel 28 by a rod 30, which is held in engagement with the block 31 by a spring 32 connected to the pivoted cross-rod 29. On winding the shutter, the projection 27 engages the rod 29 and displaces the rod 30 from the block 31, and the lever 34 is then brought by the spring 33 into engagement with the wheel 28. When the release lever 38 is operated, the rod 49 is disengaged from the arm 50, thus freeing the screen, and the upper end 39 releases the pawl-lever 34 and the shutter. For adjusting the slit 26, Fig. 14, tapes 28<1> are attached to the upper blind 27<1>, looped through the lower blind 8, pass over rollers 54, 55, 56, 57, and wind on the upper blind-roller. The roller 56 is mounted on an adjustable bearer 53, Fig. 13, which is graduated with a scale indicating the slits, and visible through a small hole in the casing.