Patent GB-926795-A (GB)
Title: A shutterless camera for obtaining an image of a surface which is in motion at a constant velocity with respect to the camera
IPC: G03B37/00
Filed: 1960-06-17
Abstract: 926,795. Photographic cameras. J. L. GAFFORD. June 17, 1960, No. 21400/60. Class 98 (1). A shutterless camera for obtaining an image of a surface which is in motion at a constant velocity with respect to the camera includes an elongated housing having a cut-out side portion provided with a transparent cover for protecting the camera lens mounted inside of said cutout side portion, an aperture plate being disposed parallel to the axis of the elongated housing and having a slit exposure aperture opposite the camera lens, a pressure plate slidably mounted face to face with said aperture plate, and resilient means urging said pressure plate toward the aperture plate, reels for perforated film being mounted on a common shaft driven by a synchronous motor disposed in the housing, whereby the film will move continuously off of one reel, pass between said aperture plate and pressure plate, around a film guide roller and return to the other reel, lamps being positioned in a light chamber close to the camera lens for directing light through said transparent cover, the arrangement being such that the ratio between the camera speed relative to the surface to be photographed and the film speed is in a predetermined relation to the magnification ratio of the camera lens. As shown (Fig. 3), a camera comprises a housing 1 with a port-hole 95, lamps 84, 85 having reflectors 86, 87 for directing light through said port-hole on to the wall of a well-hole or the like, a wide angle lens 82, 75 for focusing an image of said wall on to a slit exposure aperture 74 in a fixed plate 72, a pressure plate 69 urged by springs 78 for holding the film 42 against said exposure slit, and means for moving said film past said slit at a constant predetermined speed. Two film spools 40, 41 are provided on a common shaft 39 and either may act as take-up spool by being coupled to a synchronous motor 24 by way of a belt 57 and a friction coupling 59. Rollers such as are shown at 44, 47 and 49 are provided for guiding the film 42 to the exposure slit, and the film feed means comprises two sprocket wheels 51, 54 which engage the perforations in the film and are coupled to the synchronous motor 24 by way of worm gears 30, 33 and 31, 34 and bevel gears 26, 27. The camera may be suspended in the well-hole or the like by means of a power cable 2 (cf. Fig. 1, not shown) and the speed at which the camera is raised or lowered is made to correspond with the speed and direction of the film past the exposure slit and with the magnification of the image produced at said slit. The cable 2 is connected to a power transformer 13 and a gyroscope 16 driven by a motor 15 is provided for preventing the camera from spinning. Out-rigger apparatus may be provided externally of the housing 1 for holding the camera straight in the well-hole. The whole of the film feed mechanism including the lens 82, 75 and lamps 84, 85 is mounted on a plate 18 for easy removal from the housing 1. When assembled as shown the housing is hermetically sealed so that gas under pressure may be injected through valve 106. The camera may be used for photographing any surface moving with a uniform constant velocity relative to the camera.