Patent GB-991002-A (GB)
Title: Cine-camera with battery fed exposure meter
IPC: G03B7/085
Filed: 1961-09-19
Abstract: 991,002. Cinematograph cameras. AGFA A.G. Sept. 19,1961 [Sept.23, 1960], No. 33571/61. Headings G2A and G2E. A cine camera with battery fed exposure meter includes a manually switchable camera control device having aplurality of switched positions including a position for setting the camera for normal operation, a position for battery testing in which position the exposure meter galvanometer is electrically connected through a testing resistor to the battery and a safe position in which the battery is open circuited. In a first embodiment (Fig. 2), a battery 57 and a photo-resistor 71 may be connected by way of a resistance 72, contacts 69, 68 of a switch 6 and contacts 59, 66 of a multiple switch 60 to a galvanometer 47 for automatic control of the diaphragm aperture in front of an exposure aperture 31 by means of known pivoted diaphragm levers 52, 53 controlled respectively by way of pin and slot connection 50, 51 on a disc 49 driven by the galvanometer 47. If it is desired to manually override the automatic selection of the diaphragm aperture, the moving contact 68 of switch 6 is rotated so as to contact with a resistor strip 74, when the circuit between battery 57 and photo-resistor 71 is made via pairs of contacts 59 and 61, 68 and 74 and a resistance 73. The diaphragm is then set by the galvanometer according to the position of the contact 68 and the strip 74. However, in the safe position of a manual control knob 9 (when mark 10 and switch knob 9 registers with mark S), in which position a lug 15 on a disc 12 on the switch spindle 11 engages with the spring contact 59, this contact is raised out of contact with contact 66 and the battery is opencircuited. Before setting of the diaphragm can be effected again by the galvanometer 47, contacts 59, 66 must be allowed to reclose by moving the knob 9 into any one of the positions E, L or D as described hereafter. A battery testing position for the knob 9 is provided at B in which position the contacts 61 and 59 are made (by means of the engagement of contact 59 by lug 15) and the battery is thereby connected through a resistance 63 to the galvanometer 47 so that the condition of the battery may be gauged by the deflection thereof. By means of a spring 16 wrapped round the spindle 11 and having an end 16a engageable with a part 18 of the camera housing it is arranged that the knob 9 automatically returns to the safe position S after release of the knob 9. A shutter disc 26 is shown rotatable by means not shown in the direction 26a and having upstanding lugs 27, 28 thereon engageable for arresting purposes by a lever end 24a. The lever 24 is connected by an over-centre spring arrangement 29, 21, 23 to a camera release 5. In the safe position shown, a lug 13 of disc 12 abuts against arm 24c of lever 24 and prevents movement thereof although the release 5 is movable against loading of spring 23. In the position E of knob 9, a shorter lug 14 on disc 12 allows movement of end 24a out of the path of lug 27 (on actuation of release 5) but holds it in the path of flange 28b whereby a single exposure is obtained. On movement of the knob 9 into the position L, there is no lug in register with the arm 24c and continuous operation of the camera is possible so long as release 5 is actuated. If the knob 9 is moved into the D position while the camera is operating continuously, the lug 15 engages over the arm 24c and holds the lever 24 in the operating position regardless of whether or not the release 5 is held depressed. In order to prevent end 24a from pressing against the shutter disc 26, a fixed stop may be provided between them. The knob 9 is held in each of the specified positions by a spring- detent device. The view finder comprises, as shown, a beam splitter 32 in the path of the exposure light path, lenses 35 and 40, an image-field bounding frame 41 and prism 36. A transparent disc 43, rotatably coupled through a pin and slot connection 30, 46 to the galvanometer 47 bears an aperture scale visible in the view finder in a recess 42 of the frame 41 and also serves by the provision of index marks to indicate the condition of the battery during testing. In a modification (Fig. 3), in which the shutter is drivable by an electric motor 78 powered by a battery 79, control of the shutter for exposure is effected by a switch 80 coupled to a manual release, not shown. A switch 9a is provided with S, L and B positions as in the case of switch 9-together with a further position "M" for testing the battery 79, in which position the galvanometer 47 and battery 79 are connected through a series resistance 83 and a resistance 85 is connected in parallel by closure of a switch 86 (coupled to 9a). The switch 9a (Fig. 4-not shown) is provided with a spring detent means for locating it in the positions S, L, M, or B, but overriding spring means are provided for urging it out of the B and M positions. A switch 81 is arranged to be opened (by the switch 9a) in all positions except L. The switch 6 of Fig. 2 is here replaced by a switch 76 which may be manually opened if it is desired to set the diaphragm manually by a known direct mechanical means (not shown). The exposure meter needle 89, visible in the lower region of the view finder field 87, cooperates in the L-position with a scale 88 to indicate the diaphragm setting and in the B and M positions with a split white/red field 90, 91 to indicate when the batteries 57 and 79 respectively are in need of re-charging (the resistances 63, 83 and 85 being chosen to produce the same galvanometer deflection in both cases). The ends 92 and 93 of the scale 88 are coloured red to indicate when light conditions are not suitable for proper exposure. In a further modification (Figs. 5 and 6) provision is also made for different shutter speeds- 16 (L-position), 32 (L32 position) or 48 (L48 position)frames per sec. To compensate the diaphragm regulating mechanism for these settings, extra resistances 103, 104 are arranged to be inserted in series with the photo resistor 71 and resistance 72. Control of the motor 78 for obtaining these different speeds is by way of a governor 118 having weights 119 coupled through a sliding sleeve 120, a pin 121 passing through the hollow motor shaft 117 and a spring-urged lever arm 122 to a spring contact 125 in the supply circuit to the motor 78. Normally contacts 115o, 125 are held touching by a spring 124 but on reaching a certain speed the lever 122 is pivoted away and the circuit is broken. The contact 115a on a screw shaft 115 is positioned according to the speed set by switch 9b by means of a pinion 114, toothed segment 112 and a cam 10b on the switch spindle 11. Instead of providing resistances 103, 104, a diaphragm 129 may be provided in front of the photo resistor 71 and coupled to a cam disc 126 on the switch spindle 11 or the galvanometer may be rotatably mounted. Alternatively for direct control by the switch 9b the diaphragm 129 may be replaced by other light alternating means or several photo-electric elements may be arranged for use separately or together.