Patent GB-884180-A (GB)
Title: Shutters for photographic cameras
IPC: G03B9/22
Filed: 1959-07-07
Abstract: 884,180. Photographic shutters. NEUBERT, W. July 7, 1959 [July 17, 1958], No. 23282/59. Class 98(1). A shutter for photographic cameras comprising shutter blades which perform an oscillatory motion for opening and shutting the camera aperture is characterized in that the first half oscillation is produced by forces engendered in springs which act on the element provided for actuating the blades, said forces exceeding in magnitude the spring forces which induce the second half oscillation, and the energy of motion of the blades performing the first half oscillation being used in known manner to energize springs for driving the blades during the other half oscillation, and that the greater power applied to the performance of the first half oscillation is at least partly supplied by an energy storage spring energized by the action of setting or cocking the shutter. As shown, shutter blades 9 pivoted about fixed points 21 are controlled by an actuating ring 8, which-in the rest position shown in Fig. 2-is urged clockwise m the shutter opening direction by a strong spring 26 but is prevented from moving by a leaf spring arresting means 28, 31. On cocking of the shutter by rotation in the clockwise direction of a setting lever (not shown) coaxially mounted in the shutter housing, by way of a lever 39 caused to rotate by an abutment of said setting lever, and further by way of a member 42 pivoted on a lockable arm 41 of said lever 39, an energy storage spring 43 engageable with an abutment 44 of the ring 8 is tensioned. At the same time a lever 46 is moved to the "ready" position shown in Fig. 2 by a second abutment 45 on the setting lever. When the shutter is released, the setting lever is spring moved in the direction of arrow 38, abutment 45 moves lever 46 in the direction of arrow 46a, and abutment face 47 thereon deflects leaf spring 31 of the arresting means 31, 28 out of locking engagement with leaf spring 28, which is then deflected by the sloping portion of an abutment 34 on the ring 8 to allow this ring to rotate in the clockwise direction for opening of the shutter blades 9 under the combined tension of springs 26 and 43. When the blades 9 reach their wide open position, a further abutment on the setting lever engages a pin 59 on locking lever 40 and displaces this lever against spring bias for releasing-underloading of a weak spring 60- the arm 41 and hence also the spring 43. At the same time, an abutment 51 on ring 8 comes against a stiff U-shaped spring 50 and the direction of motion of ring 8 is thereby reversed, the ring 8 being driven during the ensuing blade closing motion by now tensioned spring 27, which is stronger than spring 26 alone but not as strong as springs 26 and 43 together. When the blades 9 reach their closed positions the ring 8 is locked by spring 28 engaging abutment 34 and being itself engaged by spring 31, the abutment face 47 now riding on ring 8 (see Fig. 3) out of interference with this latter spring. Exposure regulation. The shutter as described above and as shown in Fig. 2 is set for a minimum time exposure (say 1 /1000th sec.). For exposures of say 1/500th sec. speed setting ring 49 is moved a short distance to the right, whereupon lever 53 and return spring 50 are spring urged into the positions shown in Fig. 3, and the blade opening motion of ring 8 is reversed by means of spring 27 along. A second leaf spring arresting means 35, 36 co-operating with abutment 37 is provided for arresting the blades in the open position, but is normally held inoperative by the engagement of spring 36 by a finger of a lever 63. For exposure of say 1/250th sec. however, this second arresting means is made operative by moving the setting ring 49 further to the right, into the position shown in Fig. 3, the blades 9 then being arrested in their wide opening positions until an abutment 64 on the setting lever (which may be coupled to a retarding mechanism) engages upturned face 56 of a lever 57, the said finger of lever 63 then displacing spring 36 for releasing the arresting means 35, 36. For exposures of say 1/125th sec. speed setting ring 49 is moved even further to the right so that lever 57 moves into its alternative position (shown in dotted lines in Fig. 3), the blades 9 then being arrested in their open positions until abutment 64 engages upturned face 55 on lever 63. In alternative embodiments (Figs. 5-8, not shown) the second arresting means 35 and 36, and levers 63, 57, are dispensed with and exposure time regulation is by various arrangements of spring devices which are placed in the path of abutment 51 for reversing the direction of motion of ring 8, and which are adjustable in position or strength by the speed setting ring 49. In a further embodiment (Fig. 1, not shown), the two arresting means are in the form of spring urged locking pawls 10 and 16 and the energy storage spring 3 acts indirectly on the actuating ring through a further pawl 6. The springs 26, 27, and 50 may be arranged in symmetrical multiples, and the actuating ring 8 may be mounted on roller bearings to reduce friction (Figs. 9 and 10, not shown). In further modifications the shutter may be used in cine cameras if the tensioning of spring 43 and release of arresting means 28, 31 is effected by motor means.