| 摘要 |
An improved audio-visual machine for projecting visual information segments carried by a transparency holder in an audio-visual cartridge, and for reproducing corresponding narrative and control information recorded on a movable storage medium carried by the cartridge, is disclosed. The teaching machine includes an optical system which incorporates a movable focusing lens which is mounted on a very long lever arm. The lever arm is pivoted at one end and is adjustably mounted on a threaded post at the other end to permit motion of the lens toward and away from the transparency for focusing while still permitting maintenance of the focus across the entire width of the transparency. A drive mechanism is provided to selectively align specified visual segments with the optical system. The movable storage medium is movable independently of the transparency holder, and a transducer for reproducing audio frequency signals from the storage medium is provided. The transducer includes an improved indexing assembly to permit precise location with respect to the storage medium. The entire mechanical assembly is mounted on a single mounting plate to facilitate assembly of the machine.
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