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Compumotor Division, North America: Home > Support > Applications > Film Advance
Tangential drives consist of a pulley or pinion which, when rotated, exerts a force on a belt or racks to move a linear load. Common tangential drives include pulleys and cables, gears and toothed belts and racks and pinion.
Tangential drives permit a lot of flexibility in the design of drive mechanics, and can be very accurate with little backlash. Metal chains should be avoided since they provide little or no motor damping.
Tangential Drives permit a lot of flexibility in the design of drive mechanics. In this application a movie camera is being modified to expose each frame under computer control in order to generate special effects. A step motor is installed to index a 38 mm (1.5 inches) frame in 200 msec.
Motion Control Requirements:
A movie camera is being modified to expose each frame under computer control for the purpose of generating special effects. A motor will be installed in the camera connected to a 1/2-inch diameter, 2-inch long steel film drive sprocket and must index one frame in 200 milliseconds. The frame spacing is 28 mm (1.5").
In this application, the move distance and time are known, but the required acceleration is not known. The acceleration may be derived by observing that, for a trapezoidal move profile with equal acceleration, slew and deceleration time, 1/3 of the move time is spent accelerating and 1/3 of the total distance is travelled in that time (a trapezoidal move).
It is determined that the acceleration required is 107.4 rps
An indexer is selected to be connected to a BCD interface in the camera electronics. Preset and Slew modes on the indexer are then controlled by the camera electronics to provide fast rewind and frame indexing.
Parker Hannifin Corporation, Compumotor Division,
5500 Business Park Drive, Rohnert Park, CA 94928
707-584-7558 or 800-358-9068
Email: Technical Support
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