Motion picture projector having cam apparatus enabling stop frame projection

Claim 2

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including a first cam assembly means which moves a claw arm which periodically engages and disengages the film for advancement thereof frame by frame, the improvement comprising means for selectively disengaging said film advance mechanism from the film to allow an individual frame of said film to stop and be projected, comprising selectively operable second cam assembly means for normally maintaining said advance mechanism in a first position in which it periodically engages and disengages said film and for moving said advance mechanism to a second position in which it is disengaged from the film, said second cam assembly means including a pair of cam elements which normally remain in a given relationship with respect to one another and which move relative to one another to allow said advance mechanism to move to said second position, and selectively operable means coupled with said cam means for moving one of said cam elements relative to another.

Claim 3

An apparatus as in claim 1 wherein said selectively operable means comprises a solenoid device coupled with said cam elements for selectively rotating said cam elements with respect to one another.

Claim 4

A motion picture projector selectively operable for stop frame projection comprising an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including claw arm means moved by a cam follower riding on a rotating cam face causing said claw arm to periodically engage, move and disengage said film, means for selectively disengaging said claw arm means from the film for enabling a single frame of film to be projected, comprising cam means normally maintaining said rotating cam face in a first position in which it permits said claw arm means to periodically advance said film and for moving said rotating cam face in the direction of its axis to a second position in which it moves said claw arm means away from said film whereby said claw arm means is continually disengaged from said film, and selectively operable means coupled with said cam means for selectively causing said cam means to move said rotating cam face axially to said second position.

Claim 5

A motion picture projector selectively operable for stop frame projection comprising an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including claw arm means moved by a cam follower riding on a rotating cam face causing said claw arm to periodically engage, move and disengage said film, means for selectively disengaging said claw arm means from the film for enabling a single frame of film to be projected, comprising cam means normally maintaining said rotating cam face in a first position in which it permits said claw arm means to periodically advance said film and for moving said rotating cam face in the direction of its axis to a second position in which it moves said claw arm means away from said film whereby said claw arm means is continually disengaged from said film, and selectively operable means coupled with said cam means for selectively causing said cam means to move said rotating cam face axially to said second position.

Claim 6

A projector as in claim 3 wherein said cam means includes a pair of cam elements normally maintained in a first spaced relatiOnship, and which are movable relative to one another to move to a second spaced relationship for respectively allowing said advance mechanism to be positioned in said first and second positions thereof.

Claim 7

A projector as in claim 6 wherein said claw arm means and rotating cam face are mounted on a shaft, and a resilient member normally biasing said claw arm means and cam follower away from said film, and said cam means normally biasing said claw arm means and cam towards said film, said cam means comprising a pair of cam elements normally maintained in a first spaced relationship for normally biasing said claw arm means and cam follower towards said film, said cam elements being movable relative to one another to move to a second spaced relationship for allowing said claw arm means, rotating cam face and cam follower to be moved away from said film by said resilient member.

Claim 8

A cam mechanism for use with a film advance mechanism of a motion picture projector for allowing selective stop frame projection of motion picture film by causing said film advance mechanism to move out of engagement with said film, comprising a pair of similar cam elements each having a side with a cam surface having high and low points on said cam surface, said cam elements being mounted together with said cam surfaces adjacent one another, and means coupled with said cam elements for normally maintaining said cam elements in a position with the high points of said cam surfaces abutting one another, and for allowing said cam elements to be relatively moved to cause the high points of one cam surface to abut the low points of the other cam surface to enable said sides of said elements to move together.

Claim 9

A cam mechanism for use with a film advance mechanism of a motion picture projector for allowing selective stop frame projection of motion picture film by causing said film advance mechanism to move out of engagement with said film, comprising a pair of similar cam elements each having a side with a cam surface having high and low points on said cam surface, said cam elements being mounted together with said cam surfaces adjacent one another, and means coupled with said cam elements for normally maintaining said cam elements in a position with the high points of said cam surfaces abutting one another, and for allowing said cam elements to be relatively moved to cause the high points of one cam surface to abut the low points of the other cam surface to enable said sides of said elements to move together.

Claim 10

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including means which periodically engages and disengages the film for advancement thereof frame by frame, the improvement comprising means for selectively disengaging said film advance mechanism from the film to allow an individual frame of said film to stop and be projected, comprising selectively operable cam means for normally maintaining said advance mechanism in a first position in which it periodically engages and disengages said film and for moving said advance mechanism to a second position in which it is disengaged from the film, said cam means comprising a pair of substantially identical cam elements each having a side face with cam faces thereon, said cam faces of said elements normally engaging each other to maintain said advance mechanism in said first position, and said cam elements being movable relative to each other to move the cam faces of one element with respect to the cam faces of the other element to thereby cause said cam elements to move toward one another to allow said advance mechanism to move to said second position, and selectively operable means coupled with said cam means for moving one of said cam elements relative to the other.

Claim 11

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including means which periodically engages and disengages the film for advancement thereof frame by frame, the improvement comprising means for selectively disengaging said film advance mechanism from the film to allow an individual frame of said film to stop and be projected, comprising selectively operable cam means for normally maintaining said advance mechanism in a first position in which it periodically engages and disengages said film and for moving said advance mechanism to a second position in which it is disengaged from the film, said cam means comprising a pair of substantially identical cam elements each having a side face with cam faces thereon, said cam faces of said elements normally engaging each other to maintain said advance mechanism in said first position, and said cam elements being movable relative to each other to move the cam faces of one element with respect to the cam faces of the other element to thereby cause said cam elements to move toward one another to allow said advance mechanism to move to said second position, and selectively operable means coupled with said cam means for moving one of said cam elements relative to the other.

Claim 12

An apparatus as in claim 7 wherein said selectively operable means comprises a solenoid device coupled with said cam elements for selectively rotating said cam elements with respect to one another.

Claim 13

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including means which periodically engages and disengages the film for advancement thereof frame by frame, the improvement comprising means for selectively disengaging said film advance mechanism from the film to allow the individual frame of said film to stop and be projected, comprising selectively cam means for normally maintaining said advance mechanism in a first position in which it periodically engages and disengages said film and for moving said advance mechanism to a second position in which it is disengaged from the film, said cam means incLuding a pair of cam elements each of said cam elements having a side with a cam surface having high and low points on said cam surface, the cam elements being mounted together with said cam surfaces adjacent one another with said high points normally engaging each other to maintain said advance mechanism in said first position and said cam elements being movable relative to each other to move the high points of one element into engagement with the low points of the other element to thereby cause said cam elements to move together to allow said advance mechanism to move to said second position, and selectively operable means coupled with said cam means for moving one of said cam elements relative to another.

Claim 14

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including means which periodically engages and disengages the film for advancement thereof frame by frame, the improvement comprising means for selectively disengaging said film advance mechanism from the film to allow the individual frame of said film to stop and be projected, comprising selectively cam means for normally maintaining said advance mechanism in a first position in which it periodically engages and disengages said film and for moving said advance mechanism to a second position in which it is disengaged from the film, said cam means incLuding a pair of cam elements each of said cam elements having a side with a cam surface having high and low points on said cam surface, the cam elements being mounted together with said cam surfaces adjacent one another with said high points normally engaging each other to maintain said advance mechanism in said first position and said cam elements being movable relative to each other to move the high points of one element into engagement with the low points of the other element to thereby cause said cam elements to move together to allow said advance mechanism to move to said second position, and selectively operable means coupled with said cam means for moving one of said cam elements relative to another.

Claim 15

A motion picture projector selectively operable for stop frame projection comprising an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including means causing the same to periodically engage, move and disengage said film, means for selectively disengaging said film advance mechanism from the film for enabling a single frame of film to be projected, comprising cam means normally maintaining said advance mechanism in a first position in which it periodically advances said film and for moving said advance mechanism to a second position in which it is continually disengaged from said film, said cam means comprising a pair of substantially identical cam elements each having a side with a cam surface thereon, said cam elements being mounted together with said sides adjacent one another and said cam surfaces engaging one another, said cam elements being normally maintained in a given spaced-apart relationship, and selectively operable means coupled with said cam elements causing said cam elements to move together upon operation thereof to move said advance mechanism to said second position.

Claim 16

A motion picture projector selectively operable for stop frame projection comprising an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including means causing the same to periodically engage, move and disengage said film, means for selectively disengaging said film advance mechanism from the film for enabling a single frame of film to be projected, comprising cam means normally maintaining said advance mechanism in a first position in which it periodically advances said film and for moving said advance mechanism to a second position in which it is continually disengaged from said film, said cam means comprising a pair of substantially identical cam elements each having a side with a cam surface thereon, said cam elements being mounted together with said sides adjacent one another and said cam surfaces engaging one another, said cam elements being normally maintained in a given spaced-apart relationship, and selectively operable means coupled with said cam elements causing said cam elements to move together upon operation thereof to move said advance mechanism to said second position.

Claim 17

A motion picture projector selectively operable for stop frame projection comprising: an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including a claw arm for advancing said film and a cam for moving said claw arm causing said advance mechanism to periodically engage, move and disengage said film, said claw arm and cam being mounted on a shaft, and a resilient member normally biasing said claw arm and cam away from said film said claw arm and said cam being mounted on said shaft intermediate said resilient member and said cam elements said cam means normally biasing said claw arm and cam toward said film, said cam means comprising a pair of cam elements, each of said cam elements having a side with a cam surface thereon, said cam elements being mounted together with said sides adjacent one another and said cam surfaces engaging one another, said cam elements being rotatable with respect to one another to allow said sides to move together upon selective operation thereof to move said cam elements to a second spaced relationship for allowing said claw arm and cam to be moved away from said film by said resilient member, and selectively operable means coupled with said cam means for selectively causing said cam means to move said advance mechanism to said second spaced relationship.

Claim 18

A motion picture projector selectively operable for stop frame projection comprising: an advance mechanism for advancing film through an optical system of said projector for normal projection of said film frame by frame, said advance mechanism including a claw arm for advancing said film and a cam for moving said claw arm causing said advance mechanism to periodically engage, move and disengage said film, said claw arm and cam being mounted on a shaft, and a resilient member normally biasing said claw arm and cam away from said film said claw arm and said cam being mounted on said shaft intermediate said resilient member and said cam elements said cam means normally biasing said claw arm and cam toward said film, said cam means comprising a pair of cam elements, each of said cam elements having a side with a cam surface thereon, said cam elements being mounted together with said sides adjacent one another and said cam surfaces engaging one another, said cam elements being rotatable with respect to one another to allow said sides to move together upon selective operation thereof to move said cam elements to a second spaced relationship for allowing said claw arm and cam to be moved away from said film by said resilient member, and selectively operable means coupled with said cam means for selectively causing said cam means to move said advance mechanism to said second spaced relationship.

Claim 19

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including claw arm means moved in an oscillatory motion to periodically move said claw arm into engagement with a film strip, advance said film strip one frame and then disengage said film strip, the improvement comprising disengaging means for moving said claw arm away from said film strip while continuing said oscillatory motion of said claw arm whereby said claw arm is continually disengaged from said film, and means for selectively controlling said disengaging meanS.

Claim 20

In a motion picture projector which includes a film advance mechanism for periodically advancing film for normal continuous projection thereof, said film advance mechanism including claw arm means moved in an oscillatory motion to periodically move said claw arm into engagement with a film strip, advance said film strip one frame and then disengage said film strip, the improvement comprising disengaging means for moving said claw arm away from said film strip while continuing said oscillatory motion of said claw arm whereby said claw arm is continually disengaged from said film, and means for selectively controlling said disengaging meanS.