Patent GB-190309572-A (GB)
Title: Improvements in Shutters for Photographic Cameras
Inventor: WRIGHT JOHN STRATTON
Filed: 1903-04-28
Granted: 1903-06-25
Abstract: 9572. Wright, J. S. April 28. Shutters.-Relates to shutters for cameras, located in the front or rear of the lens, or between the lenses when a double lens is used, or in the focal plane of the lens, the latter case being illustrated. The shutters may be adjusted for instantaneous or time exposures. The curtain 21, Figs. 4 and 14, is in two parts 22, 23, separated by a slot 24, and secured, respectively, to rolls 25, 26. The roll 25 has an annular ring 28 at one end and a disc 29 at the other end secured to a sleeve 30, which has teeth 31 on the outer end engaging a wheel 32, Fig. 3, having. a stop tooth 34 to bring the parts to rest. A spindle 36 within the tube has a fixed disc 39 attached to one end of a spring 38, the other end being attached to a disc 35 fixed to the tube and capable of rotating on the spindle. A clutch disc 40 fixed to the spindle is recessed to engage a spring pin 42 upon the disc 35 to lock the spindle and tube together by drawing the spindle to the left by means of the thumb-piece 43. A ratchet-wheel 44 engages a pivoted pawl 45, which prevents the spring from unwinding. The tube composing the lower roll has a disc 52 secured to a sleeve 53 provided with teeth encaging the stop pinion 55. The spring 61 is similarly attached to the spindle 59 and to the disc 58, which carries a pin to engage the sliding clutch 63. A pawl 68 prevents the spring from unwinding. In operation, one spindle is locked to the tube while the other is free, and to ensure this arrangement a pivoted lever 72 is provided having its ends bearing against the thumb-pieces, so that one spindle is moved outwards when the other is moved inwards. The lever carries stops 74, 75, which alternately move into line with pneumatic pistons 48, 71 in the tube 49, to which air is passed through the flexible tube 50. The free piston acts upon one of the pawls 45, 68 to release the corresponding spring, which then winds the curtain from one roller upon the other and gives the exposure by the slot passing across the plate. The curtain is attached to the roll by removing section 103, Fig. 8, of the tube 51, passing one end of the curtain between the section and the tube, and screwing the section down to the end discs. The speed of the slot travelling across the plate is regulated by the amount the springs are wound up, and this amount is indicated by means of arrows on the casing and the thumb-pieces, respectively. To adjust the width of the slot, the curtain is wound on the lower roll, both springs are then wound up and the parts are in the relative positions shown in Fig. 4. By rotating the upper thumb-piece, the slot is moved from the roll 26, as shown in Fig. 14, and the wheel 55, Fig. 3, is moved into position for a slide 77 to enter one of the spaces 76 to lock the lower roll to the casing 20. The upper part of the curtain is then moved to decrease or increase the width of the slot by means of the slide shown separately in Fig. 15 having a cylindrical portion 78 sliding in the sleeve 79, Fig. 4, and a finger 81 to engage spaces in the disc 83 secured to the tube 51. The finger projects through a spurwheel 84 and a tape reel 5, both of which rotate with the thumb piece 80; the spur-wheel 84, by means of pinions on the shaft 88 and a second spur wheel 89, rotates a second tape reel 90. The reels carry tapes 91, 92, one end of each tape is secured to its reel and the other end to the eyes 96 on the part 23 of the curtain after passing through eyes 93, Fig. 10, formed in a flat strip of metal 95 on the part 22 of the curtain. By rotating the thumb-piece 80, the tapes are either unwound from, or wound upon, the reels, to increase or decrease the width of the slot. A stop 99, Fig. 15, prevents the slide from moving too far to the right. The flange 101 on the sleeve 79 is graduated to indicate the width of the slot, After the adjustment of the slot the thumbpiece is pushed inwards, and the curtain is then ready for operation.