Patent GB-629591-A (GB)
Title: Improvements in photographic cameras provided with rangefinders
IPC: G03B13/20
Filed: 1946-01-24
Abstract: 629,591. Photographic cameras. MONTREMY, J. DE. Jan. 24, 1946, No. 2377. Convention date, Jan. 29, 1945. [Class 98 (i)] A photographic camera including a range-finder coupled with the focusing device, in which the objective lens is mounted in a support freely slidable axially with respect to the camera body against the action of opposing spring means, and the rangefinder includes a mirror carried by a support pivoted to the frame at a point spaced from the rangefinder objective and urged by spring means to pivot in one direction, is characterized in that a screw, operable from outside the camera, rotates in a threaded portion of the camera body, one end of the screw being in contact with a lever pivoted to the frame to transmit the longitudinal movements of the screw to the lens mount against the action of its associated spring means, and with a movable element, interposed between the other end of the screw and the mirror support and acted upon by a third.spring means, which transmits the longitudinal movement of the screw to pivot the support against its spring means. The screw may be rotated by means of a disc thereon projecting outside the camera casing. A retractable colour filter may be mounted in the casing. The camera may be of rectangular shape, having a box frame 1, Fig. 2, with a cylindrical opening 2 in which slides axially a sleeve 4 with a square flange 5 in which the objective lens 6 is mounted. Four holes in the box 1 contain springs acting on the flange 5 to urge the sleeve 4 away from the film in the gate 3. One end of a lever 8 pivoted to the frame 1 at 9 has a fork 7 bearing on the sleeve 4; the other end bears on the end of a screw 10 threaded in the frame and rotatable by a disc 10<SP>1</SP> thereon projecting outside the camera. An element 15 is spring-urged against the other end of the screw, and abuts a part 13, Fig. 3 (Cancelled), pressed into contact therewith by a spring 14 and forming part of a support, pivoted at 12 and carrying a mirror 11 by adjusting screws 22. At the other side of the camera is a concave lens 18 mounted in front of a cube 19 formed of triangular prisms, one of the faces having a small depression 20. The lens 18, together with an eyepiece 17, forms an inverted Galilean telescope constituting the viewfinder. Light entering an aperture in the casing and reflected by the movable mirror 11 passes through a lens 21 of the same power as lens 18 and at the same distance from the centre of cube 19, and is reflected at the surface opposite depression 20. The mirror 11 is adjusted by screw 10 until the images obtained by the two optical paths coincide, movement of the screw simultaneously focusing the objective 6 on the object by the action of lever 8. A colour filter 26, Fig. 2, is mounted in a frame 27 which slides in front of or away from the objective 6 on pillars 28, by action of a lever 29 with a pin-and-groove connection with the frame 27. The Specification as open to inspection under Sect. 91 comprises also a diaphragm adjustable by a ring on the sleeve 4 by means of a knob thereon projecting through the casing, and a roller-blind shutter. The shutter blinds are wound from spring-loaded rollers 32, 33 to rollers 34, 35, Fig. 2. When the winding key is turned to set the shutter, a large pinion 38, Fig. 3, (Cancelled), meshing with a pinion 40 fast with one of the rollers 34, 35, is rotated to wind one blind. A pin on pinion 40 moves in a groove in a second pinion (not shown) free on the same shaft; it reaches the end of the groove when the exposure slot is closed and thereafter turns the second pinion which drives the second winding roller through a pinion 43 to wind the blinds together. Pinion 43 drives a large pinion 44 through nearly 360 degrees during the winding of the blinds; at the end of this process a spring-urged finger 45 on pinion 44 drops into an opening in the casing 1. At the same moment pinion 40 is freed on reaching a gap 381 in the teeth of pinion 38, and turns under tension of the first blind until its pin reaches the other end of its groove, re-forming the exposure slot, pinion 38 being locked by a pawl on a spring-urged lever 49. The shutter release knob releases pinion 44 by pushing finger 45 out of its socket, allowing the blinds to be rewound on rollers 32, 33, effecting the exposure. The finger 45 strikes lever 49, releasing pinion 38 and braking the shutter, just before striking a stop at the end of its travel. The shutter is braked during travel by. friction of a spring 54, of variable tension by screw adjustment, on a pinion 53 driven by pinion 44. Slot width is varied by adjusting the angular position of pinion 43 relative to the roller which it drives. For bulb exposures, a tongue lowered by depression of the release knob arrests the finger 45 during the exposure movement of the parts. The film may be of 16 mm. width and may be wound by means actuated by the shutter setting mechanism. An exposure counter 59 may be provided. This subject-matter does not appear in the Specification as accepted.