Film support for photomechanical camera

Claim 1

A VACUUM TYPE SHEET SUPPORT FOR USE WITH A PHOTOGRAPHIC CAMERA COMPRISING A FACE PLATE HAVING A PLURALITY OF CLOSELY SPACED OPENINGS DISTRIBUTED THEREOVER FOR APPLYING A SUCTION FORCE TO A SHEET OF FLIM FOR MAINTAINING IT THEREAGAINST IN THE FOCAL PLANE OF SAID CAMERA, A BACK PLATE, MEANS MOUNTING SAID BACK PLATE IN SPACED COOPERATING RELATIONSHIP WITH SAID FACE PLATE, RIB SECTIONS ON SAID BACK PLATE FORMING AT LEAST THREE INTERNESTED, GENERALLY CONCENTRIC, SEPARATE MANIFOLD CHAMBERS BETWEEN SAID FACE AND BACK PLATES, A SUCTION CONDUIT, MEANS MOUNTING SAID CONDUIT ACROSS THE MIDDLE OF SAID BACK PLATE, MEANS COMMUNICATING SAID CONDUIT AND EACH OF SAID MANIFOLD CHAMBERS FOR SUPPLYING SUCTION SUBSTANTIALLY SIMULTANEOUSLY TO EACH OF SAID CHAMBERS, A FIRST INTERNAL PLATE, MEANS MOUNTING SAID FIRST PLATE IN ABUTTING RELATIONSHIP WITH THE REAR OF SAID FACE PLATE, A SECOND INTERNAL PLATE, MEANS MOUNTING SAID SECOND PLATE BETWEEN SAID FIRST INTERNAL PLATE AND SAID BACK PLATE, SAID FIRST AND SECOND INTERNAL PLATES PROVIDED WITH CONCENTRIC COOPERATING APERTURES AT THE CENTRAL PORTION THEREOF FOR FORMING A CENTRAL ACCESS CHAMBER COMMUNICATING THE CENTRAL PORTION OF SAID FACE PLATE WITH THE INNERMOST OF SAID MANIFOLD CHAMBERS, FIRST CHANNELS FORMED IN THE FIRST INTERNAL PLATE AND EXTENDING FROM SAID CENTRAL ACCESS CHAMBER RADIALLY FOR CONDUCTING SUCTION FROM SAID INNERMOST MANIFOLD CHAMBER TO SUBSTANTIALLY THE ENTIRE OF SAID FACE PLATE, SAID FIRST CHANNELS BEING DEFINED BY SAID FIRST PLATE AND SAID SECOND INTERNAL PLATE AND CONSTRUCTED AND ARRANGED SYMMETRICALLY IN SAID FIRST INTERNAL PLATE, OPPOSED CHANNELS BEING OF SUBSTANTIALLY THE SAME LENGTH, A PLURALITY OF SECOND CHANNELS FORMED RADIALLY IN SAID FIRST INTERNAL PLATE AND DISPOSED BETWEEN SAID FIRST CHANNELS EXTENDING FROM A POINT REMOTE FROM SAID CENTRAL ACCESS CHAMBER TO THE EXTREMITIES OF SAID FACE PLATE, MEANS ASSOCIATED WITH EACH OF SAID SECOND CHANNELS FOR COMMUNICATING SAID SECOND CHANNELS DIRECTLY WITH THE INTERMEDIATE MANIFOLD CHAMBER, AND PASSAGES OPERATIVELY INTERCONNECTING THE OUTERMOST MANIFOLD CHAMBER WITH EACH OF SAID FIRST CHANNELS AT AN INTEMEDIATE POINT IN THE LENGTH OF SAID CHANNELS, SAID FIRST AND SECOND CHANNELS COOPERATING TO SUPPLY SUCTION SYMMETRICALLY TO SAID FACE PLATE IN ZONES OF CONCENTRIC, SUBSTANTIALLY EQUAL PRESSURES.