Patent GB-384988-A (GB)
Title: Improvements in or relating to the method of and apparatus for feeding or pulling tape
IPC: G03B21/134
Filed: 1931-03-11
Abstract: 384,988. Changing signs. TRANSLUX DAYLIGHT PICTURE SCREEN CORPORATION, 247, Park Avenue, New York, U.S.A.-(Assignees of Curtis, K. L.; 152, East 22nd Street, New York, U.S.A.) March 11, 1931, No. 7481. Convention date, April 5, 1930. Void [Published under Sect. 91 of the Acts]. [Class 3 (i).] Opticalprojection apparatus.-In a projection system wherein a character-bearing tape passes from printing-mechanism, such as stock ticker mechanism or typewriter mechanism, the tape is supported during movement through a projection field in a different direction from its first direction and a twisted loop is formed adjacent the entrance to the projection field which controls the movement of the tape through the projection field in response to the change in configuration of the loop. The printed tape T, Fig. 1, passes from the printing- mechanism A and its direction is diverted so that a twisted loop is formed at the entrance to a projection field or zone. The tape is pulled by coacting rollers 1, 2, the roller 2 being rotated through worm gearing by a motor M and the roller 1 being an idler roller which is mounted on a spring-pressed arm 3. An air chamber H is provided with an opening 20, Fig. 2, which is normally closed by the tape loop, and through which air may be drawn by means of motor-driven fan 17 connected to the chamber H by a conduit 16. One wire of the circuit of the motor M is connected to contact members 22, 23, Fig. 2, by means of leads 20, 21 respectively. The contact member 23 is connected by an insulating member 25 to a rod 26 carried by a piston 27 in a cylinder 28 which may be mounted on the projection apparatus. The cylinder 28 communicates by a passage 30 in a member 29 with the air chamber H so that when the opening 20 in the air chamber H is closed by the tape the vacuum created by the fan 17 draws the piston 27 inwardly of the cylinder 28 to maintain the member 23 in contact with the member 22. When the size of the loop of the tape T is decreased owing to a decrease or a stoppage of the feed from the printing- mechanism A the loop no longer covers the opening 20 in the air chamber H, air therefore enters and the piston 27 moves outwardly to break the circuit of the tape-pulling motor M- by separating the contact members 22, 23. The tape T will remain stationary in the projection field until a sufficient amount has been ejected from the printing-mechanism to form a loop such that the opening 20 in the air chamber H is closed by the side of the loop, when a vacuum is again created by the fan 17 and the piston 27 drawn inwardly to close the circuit of the motor M. A weighted lever 31, pivoted at 32 on a member 24, is provided with a curved end 31a which presses the tape T on the rounded nose of the chamber H to resist the pull of the rollers 1, 2 and keep the tape taut in the projection field. Since the tape twists in a gradual manner the configuration of the exterior wall of the air chamber H is correspondingly shaped. The projection field may comprise an aperture at the front of a condenser-housing 10 into which light passes from a light-housing 11. The light passes through the aperture in the housing 10 and is reflected by a mirror 12 through a lens 13 on to a screen. A reflecting-system may be used instead of a " through " projection system. Instead of opening the circuit of the motor M resistances may be introduced in the circuit and varied to change the speed of the motor. In a modification the tape is passed from the printing-mechanism flatwise and in a horizontal direction and then given a 180‹ twist so that it passes through the projection field flatwise in a direction at right-angles to its first direction and with the tape upside down. A loop formed at the twist is utilized as before to cover an opening in an air chamber for controlling the feed of the tape through a projection system. A weighted or spring-biased member or any other device may be provided to press the tape against a fixed surface to provide the necessary tautness during passage through the projection field. The controlling-device for the tapepulling motor may be actuated when the flow of air through the opening in the air chamber is varied by the tape loop.