Flickerless projector

Claim 2

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; a constant speed first motor for driving said stepping means and an adjustable speed second motor for driving said film supply means.

Claim 3

Apparatus as set forth in claim 1 in which speed of said second motor is continuously adjustable over an operational range.

Claim 4

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; a motor for driving said stepping means; said stepping meaNs including a portion providing an interruptable driving connection between said motor and a film strip to be moved by said stepping means; said first means including biasing means urging said portion toward a first position wherein said stepping means is effective to move film; said first means also including a section for operating said portion against force of said biasing means to a second position wherein said stepping means is ineffective to more film; actuation of said section being controlled by said control signals.

Claim 5

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; a motor for driving said stepping means; said stepping meaNs including a portion providing an interruptable driving connection between said motor and a film strip to be moved by said stepping means; said first means including biasing means urging said portion toward a first position wherein said stepping means is effective to move film; said first means also including a section for operating said portion against force of said biasing means to a second position wherein said stepping means is ineffective to more film; actuation of said section being controlled by said control signals.

Claim 6

Apparatus as set forth in claim 3, in which there is a constant speed first motor for driving said stepping means and an adjustable speed second motor for driving said film supply means.

Claim 7

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; said stepping means including a film advancing claw mounted for movement between a film driving position and an idle position; biasing means urging said claw to said film driving position; cam means for operating said claw to said idler position; latch means for maintaining said claw in said idle position; actuation of said first means responsive to said control signals being effective to release said latch means and permit said biasing means to operate said claw to said film driving position.

Claim 8

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; said stepping means including a film advancing claw mounted for movement between a film driving position and an idle position; biasing means urging said claw to said film driving position; cam means for operating said claw to said idler position; latch means for maintaining said claw in said idle position; actuation of said first means responsive to said control signals being effective to release said latch means and permit said biasing means to operate said claw to said film driving position.

Claim 9

Apparatus as set forth in claim 5 in which said first means includes an electromagnet which upon energization thereof releases said latch means; additional means for energizing said electromagnet responsive to each of said control signals generated by said second means; further means for deenergizing said electromagnet between occurrences of said control signals after said claw has moved to said film driving position.

Claim 10

Apparatus as set forth in claim 6, in which there is a constant speed means for driving said stepping means; and means continuously adjustable in speed within an operational range for driving said film supply means.

Claim 11

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; said stepping means including a Geneva mechanism including a star wheel and a driving pin; means mounting said pin for rotation about an axis extending parallel to said pin and laterally offset therefrom; biasing means urging said pin to a driving position wherein for each revolution of said pin about said axis said pin engages said wheel and rotates the latter through a partial revolution; actuation of said first means responsive to said control signals being effective to retract said pin from said driving position to an idle position wherein rotation of said pin about said axis is ineffective to impart motion to said wheel.

Claim 12

Apparatus for moving a film strip including a stepping means for imparting intermittent motion to a film strip; a film supply means for delivering film to said stepping means; first means for operating said stepping means to move a predetermined length of film delivered to said stepping means by said supply means; second means for generating a control signal each time said supply means has delivered said predetermined length of film to said stepping means; said control signals being coupled to said first means to control operation thereof whereby the frequency at which control signals are received by said second means determines the stepping rate for film being moved by said stepping means; said stepping means including a Geneva mechanism including a star wheel and a driving pin; means mounting said pin for rotation about an axis extending parallel to said pin and laterally offset therefrom; biasing means urging said pin to a driving position wherein for each revolution of said pin about said axis said pin engages said wheel and rotates the latter through a partial revolution; actuation of said first means responsive to said control signals being effective to retract said pin from said driving position to an idle position wherein rotation of said pin about said axis is ineffective to impart motion to said wheel.

Claim 13

Apparatus as set forth in claim 8, in which said first means includes an electromagnet which upon energization theReof operation said pin from said driving position to said idle position; additional means for energizing said electromagnet responsive to each of said control signals generated by said second means; further means for deenergizing said electromagnet after each time said wheel is rotated through said partial revolution by said pin; a constant speed means for driving said stepping means; and means continuously adjustable in speed within an operational range for driving said film supply means.