Abstract: A motion-picture-projection system has a top intermittent sprocket (1) and a bottom intermittent sprocket (6) that are rotated intermittently in unison by mechanical and/or electrical means (8, 9, 19, 20, 21, 22, 23, 24) for conveyance of film (3) through a film gate (4) without formation of loops of film between the top intermittent sprocket and the film-gate outlet sprocket. To compensate for differences of length of unreeled film due to its cyclic advance and film-frame stoppage, compensatory loops (16, 17) are formed prior to instead of after a top intermittent sprocket and after instead of before a film-gate outlet sprocket. A film-contact surface (25, 26) of a film gate is arcuate and bordered with non-abrasive and suitably pliable material to minimize film wear. Air can be pumped onto the film for cooling and for distortion contamination resulting from heat absorption formation that is related to film "breathing".
Abstract: Mounted on a horizontal shaft 1 extending along surfaces of a film f are sprocket wheels 2 each having three tooth pairs 2a adapted to engage with perforations on the film. The tooth pairs 2a are angularily spaced apart from each other by 120 degrees around a periphery of the sprocket wheel 2. A triangular cam 11 is attached on one end of a horizontal shaft 7 rotatable in unison with the shaft 1. A lever 17 is attached to a horizontal shaft 15 carrying a cam follower 16 rotatable in unison with the rotation of the cam 11. A projection 20 which reciprocates registration pins 22 for engagement with and disengagement from the perforations g of the film f is fitted into an elongated slot 17a of the lever 17. A switching lever 14 is provided for displacement of the shaft 7 into a position where the shaft 7 is prevented from rotating even when the horizontal shaft 1 is rotated.
Abstract: A camera which includes film transport means for moving a strip of film past a lens and shutter assembly in a stepwise, frame by frame sequence, with the film being maintained stationary when the shutter is in the open position. A toothed driven gear is in operative engagement with a film driven reel. A mutilated drive gear having a toothed portion with an end gear tooth and a smooth peripheral portion is rotated in time relationship with the opening and closing of the shutter. The driven gear contains a space between adjacent gear teeth (as by removing one gear tooth) whereby the end tooth of the drive gear is received in said space to facilitate the smooth "meshing" of the drive gear with the driven gear.
Abstract: A hand held motion picture viewer includes a housing having a recess formed in one end of the housing for carrying a film cartridge, and a viewing aperture in the opposite end of the housing through which the images on the film in the cartridge may be viewed. The housing carries a film driving mechanism for engaging and advancing the film within the cartridge past the viewing aperture. The film driving mechanism includes a battery operated motor, a claw journaled for rotation within the housing and positioned to engage sprocket holes in the film when the cartridge is carried within the recess of the viewer, and a gear transmission means connected between the motor and the claw for rotating the claw in discrete arcuate steps when the motor is energized to produce intermittent film advance. An actuating lever and movable contact means are provided for selective electrical connection of the motor with the battery for selective energization of the motor and film advance.
Abstract: The present invention relates to a motion picture camera which includes a film feeding device for intermittently feeding a film for recording picture information on the film and the sound information on the film exposing part of the film. A sound recording device for recording sound information on the film, and a film constant speed feeding device for feeding the film to the sound recording position of the sound recording device at a constant speed are provided. A driving motor for driving the film constant speed feeding device and a reduction gear mechanism is provided between the driving motor and the film constant speed feeding device, whereby the driving power of the driving motor is transmitted to the film constant speed feeding device through the reduction gear mechanism in such a manner that the film constant speed feeding device is rotated at a constant speed.
Abstract: A film tension absorbing mechanism is provided on a motion picture projector for absorbing film tension shock in the film strip. The tension absorbing mechanism includes a first system comprising the combination of a pivotally mounted, biased film exit guide roller for absorbing a portion of the tension and a tension absorbing sprocket drive to permit relative movement between the film strip and the sprocket. The tension absorbing sprocket includes a sprocket wheel and a relatively movable sprocket tooth ring rotatably mounted for generally conjoint rotation. The sprocket tooth ring is biased in a direction opposite the rotation of the sprocket wheel so that film tension shock can be absorbed as the sprocket tooth ring rotates relative to the sprocket wheel in a direction against the biasing force. A second system also is provided and includes a bi-directional tension absorbing drive sprocket for absorbing film tension shock in two directions.
December 17, 1975
Date of Patent:
May 2, 1978
Bell & Howell Company
Vincent S. Pasturczak, Peter S. Mischenko
Abstract: A film drive for a motion-picture camera or projector has a film drive wheel which is rotatable about a first axis and has a plurality of angularly equi-spaced and radially extending teeth. A function cam rotatable about a second axis spaced from and perpendicular to the film axis has a generally helical peripheral formation which engages with the teeth of the wheel. This helical formation includes an intermittent-drive section having a holding portion constituting almost a complete turn of the formation of zero degree pitch and a switching portion at each end of the holding portion of predetermined pitch greater than zero degrees, and a constant-drive section of constant pitch greater than zero degrees and axially offset from the intermittent-drive section.
Abstract: The present invention refers to a motion picture camera which is characterized in that respectively on the driving shaft to be rotated by means of a driving power from the driving motor and on the shutter shaft to be rotated by means of a rotating power of the above mentioned driving shaft elliptical gears in mutual engagement with each other are provided in such a manner that the ratio of the angular speed to be communicated between the driving shaft and the shutter shaft is continuously increased and decreased while on the above mentioned shutter shaft a non-circular cam to reciprocate the claw for feeding film is provided in such a manner that while the shutter blade is opened the shutter shaft rotates slowly and further the claw for feeding film stops feeding film whereby the effective proper opening angle of the shutter blade is changed largely by means of the above mentioned pair of elliptical gears and the non-circular cam.
Abstract: A mechanical drive arrangement for a cinematograph projector. A double-sided tooth drive belt passes, in succession, over a motor driven, film take-up sprocket, idler sprocket, intermittent drive sprocket, film feed sprocket and shutter drive sprocket. The intermittent drive sprocket and intermittent motion film sprocket are mounted on a rotatable disc. The axis of rotation of the disc coincides with the circumference of the intermittent drive sprocket at the point where the plane through the axes of both mounted sprockets cuts the region of engagement of the drive belt around that circumference. In consequence, rotation of the disc moves the film anchor point, on the intermittent motion film sprocket, with only slight rotation of the shutter drive. Thereby, ghosting is avoided when racking.
June 21, 1974
Date of Patent:
March 30, 1976
Westrex Company Limited
Leroy Gordon Osborn, George Hunnam Brownlee