The Film Path Through The Projector
- Introduction
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This picture shows a simplified diagram of the internals of a Kalee Model 20 projector. The film should be laced into the projector starting at the intermittent sprocket. Turn the film until the soundtrack is closest to you.
- The Fire Guard
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The fire guard is a carry over from the time when nitro based film was still used. This film was highly flammable, and the fire guard was used to prevent flames travelling up the film and to the reel above.
- Feed Sprocket
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The feed sprocket draws film into the projector from the spool tower.
- Feed Roller
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The feed roller keeps the film locked onto the feed sprocket.
- Feed Support Pin
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The feed support pin prevents the film from wrapping itself around the feed sprocket in the event of a snap.
- Internittent Sprocket
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The intermittent sprocket pulls film past the gate one frame at a time
- Pull Sprocket
- The pull sprocket pulls teh film from the intermittentsprocket and feeds it to the sound head.
- Pull Roller
- The pull roller keeps the film engaged with the pull sprocket.
- Sound Roller 1
- This roller guides the film into the sound head.
- Impedence Roller
- The impedence roller is connected to a heavy ,balanced wheel. Its job is to keep the film as steady as possible as it passes the sound head.
- Sound Guide
- The sound guide presses the film onto the impedence roller, and also keeps the film from wobbling side to side.
- Sound Sprocket
- This sprocket isolates the sound roller from the exit sprocket.
- Exit Sprocket
- The exit sprocket lets the film out of the projector to be taken up by the tower.
- Sound Roller 2
- Holds the film onto the sound sprocket.
- Exit Roller
- Holds the film onto the exit sprocket.
- Exciter
- The Exciter lamp housing holds the exciter lamp that provides light for the sound system, and the photocell that turns the optical sound track into electrical signals that are fed to the dolby system.
- Gate
- The gate holds the film against the mask and the intermittent sprocket.
- Gate House
- The gate house holds the mask and an electric dowser to protect the film in case of motor failure.
- Mask
- The mask masks the light from the main bulbso that it fits the aspect of the film. Hence there are different masks for each of the three most common film aspect ratios.
