Patent GB-190219363-A (GB)
Title: Improvements in or connected with Photographic Cameras.
Filed: 1902-09-03
Granted: 1903-07-09
Abstract: 19,363. Newman, A. S., and Newman & Guardia. Sept. 3. Cameras; shutters.-A blind shutter is provided in front of the plate, and a mirror 35 is used for focussing. Special means are provided for varying the exposure, and for operating the shutter and the mirror. For varying the exposure, two blinds 1, 2 are used, as shown in Fig. 5. The blinds are wound on spring rollers 5, 7 at the bottom and on winding-up rollers 6, 8 at the top. The rollers 6, 8 are geared together by toothed wheels 12, 11, 10,9. The intermediate wheels 10,11 are mounted on a shaft 13, Fig. 7, and are pressed together by a spring 16, forming a friction clutch. When the shutter is released, both blinds are drawn down simultaneously. It is possible, however, to displace the apertures 3, 4 relatively, and so to shorten the exposure, by continuing the rotation of the roller 8 after the blind 1 has been fully wound up. This movement is permitted by the wheel 11 slipping on the wheel 10. Fig. 7 shows means for limiting the extent of the movement. The pin 23 fixed on the shaft 13, to which the wheel 10 is rigidly attached, after completing a revolution, turns the clutch-sleeve 19. After two revolutions, the sleeve 20 is turned by the sleeve 19, and, finally, after four revolutions the sleeve 21 comes in contact with the pin 29 on the loose wheel 11. The movement of the wheel 11 with regard to the wheel 10 is therefore limited to four revolutions. The displacement of the roller 8 with regard to the roller and, consequently, the size of the aperture in the blinds, is registered by the indicating - disc 32, Fig. 1. Fig. 6 shows the securing and releasing apparatus for the shutter. The roller 6 carries a disc with a notch 47, and is geared by toothed wheels with a disc 51 having a notch 52. The catch-levers 30, 36 have pairs of projections 53, 55 and 54, 56, which engage simultaneously with the notches 47, 52. The roller 6 and disc 51 are so geared together that the notches are only brought into position for engagement when the shutter has made its full movement, for instance after the roller 6 has made four and a half turns and the disc 51 one and a half. To hold the roller 6 during the winding-up of the shutter, the lever 36<a> engages with the ratchet-teeth 36<b>. The lever 36<a> is disengaged simultaneously with the catchlever 36. The catch-levers 30, 36 are operated by the mechanism for moving the mirror 35 shown in Fig. 1. When the mirror is moved down, so that it is inclined at 45‹ for focussing, the pin 44 on the disc 41 moves the bar 38 to the left. The bar 38 then disengages the catch 30, and the shutter is free and may be wound up. During the winding- up, the plate is screened by the mirror 35, so that it is not exposed while the aperture in the blinds is travelling upwards. On turning the mirror 35 to the raised position, the pin 45 draws back the bar 38, which releases the catch 36 and makes the exposure. In order that the mirror may be raised rapidly, a spiral spring 59 is fitted on the axis of the disc 41, as shown in Fig. 2. When the mirror is turned down by rotating the knob 43, it is held by the engagement of the pin 61 on the disc 41 with a projection 62 on the bar 60. When the knob 63 is pressed, the mirror is raised rapidly by the spring 59. By holding the knob 43, the mirror may be allowed to rise slowly. For giving a time exposure, the shutter blind is wound up till the aperture is in the centre. The knob 63 is pressed in and immediately released, the mirror rising sufficiently to expose the plate, but its full movement being prevented by the stud 64 engaging the projection 62. To terminate the exposure, the knob 63 is pressed in a second time. The pin 64 being released, the spring causes the mirror 35 to complete its upward movement, so that the bar 38 releases the shutter catch and the spring rollers draw the shutter down.