Film-sound synchronization system

A system for simultaneously filming a motion picture and recording sound on a record medium separate from the film, and for projecting the motion picture and playing back the recorded sound in synchronism, said system comprising:

• a. a first line providing electrical power from an AC source;
• b. a recording and playback unit including an electric motor for driving a record medium past a stationary transducer for recording on and picking up from said record medium audible sounds, an electrical system for converting sound to electrical signals and vice versa, and a plurality of switches for starting and stopping movement of said record medium and operation of said electrical system for recording or playing back;
• c. a movie camera;
• d. a movie projector;
• e. means for converting AC power from said source to DC power at a voltage level appropriate to operate said camera;
• f. a second line connecting said camera to said converting means;
• g. a first switch in said second line which is closed in response to closure of one of said plurality of switches which initiates movement of said record medium for recording, and is opened in response to closure of another of said plurality of switches which stops movement of said record medium, whereby operation of said camera is started and stopped simultaneously with starting and stopping of recording on said record medium;
• h. a third line connecting said electrical system to said first line;
• i. a fourth line connecting said movie projector to said first line;
• and
• j. a fifth line connecting said motor to said first line.

An adapter unit for use with a motion picture camera and projector and a sound recording and playback unit to synchronize projection and playback of the movie and sound which were recorded simultaneously, said unit comprising:

• a. a first line providing power from an AC source;
• b. means for converting AC power from said source to DC power of appropriate voltage for operating a movie camera;
• c. a first receptacle at which said DC power is available;
• d. a first switch between said first receptacle and said converting means;
• e. a second line connected between said first line and a second receptacle providing AC power at said second receptacle for operation of a movie projector;
• f. a third line connected between said first line and a motor adapted to drive a record medium on which sound is recorded;
• g. a second switch in said second line selectively operable to interrupt AC power to said second receptacle to allow the record medium to operate at a faster rate than the projector for a selected time interval until synchronism between projection of the motion picture and playback of the sound recording is restored;
• and
• h. a third switch in said third line selectively operable to interrupt power to said motor to allow the projector to operate at a faster rate than the record medium for a selected time interval until synchronism between playback of the sound recording and projection of the motion picture is restored.

A system for manually restoring synchronism of projection of a motion picture film with playback of sound recorded on a record medium separate from the film, said system comprising:

• a. a playback unit including an electric motor for driving the record medium past a stationary pickup means and an electrical sound system for producing audible sound from the movement of said medium past said pickup means;
• b. a first line providing a regulated voltage to operate said sound system;
• c. a second line connected between said motor and source other than through said sound system for providing a regulated voltage to operate said motor;
• and
• d. manually operable switch means selectively movable to vary the speed of said motor between rates both faster and slower than the normal speed thereof for selected time intervals to restore synchronism between projection of the motion picture and playback of the sound recording without affecting said regulated voltage operating said sound system.

A system for manually restoring synchronism of projection of a motion picture film with playback of sound recorded on a record medium separate from the film, said system comprising:

• a. a playback unit including an electric motor for driving the record medium past a stationary pickup means and an electrical sound system for producing audible sound from the movement of said medium past said pickup means;
• b. a first line providing a regulated voltage to operate said sound system;
• c. a second line connected between said motor and source other than through said sound system for providing a regulated voltage to operate said motor;
• d. manually operable switch means selectively movable to vary the speed of said motor between rates both faster and slower than the normal speed thereof for selected time intervals to restore synchronism between projection of the motion picture and playback of the sound recording without affecting said regulated voltage operating said sound system;
• and
• e. light responsive means for connecting said first and second lines with a power source in response to a predetermined increase in the intensity of light incident on a photosensitive element of said light responsive means.