Lockup for thin plates

Claim 2

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining a first undercut surface for seating the inwardly bent leading edge of the plate and a second undercut surface arranged opposite thereto, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring having a first leg presenting a tip opposite the first undercut surface in position for bearing upon the leading edge of the plate and a second leg having an edge of hook cross section nested with the second undercut surface and extending under the inwardly bent trailing edge of the plate, means including a spring actuating cam shaft extending the length of the U-shaped spring along the trailing edge side of the slot and having a longitudinal ridge for applying force to the central portion of the second leg, force transmitting means bridging the space between the legs so that when the cam is rotated the force transmitting member causes the tip of the first leg to be brought to bear against the leading edge of the plate to hold it captively seated against the first undercut surface accompanied by movement of the edge of hook cross section on the second leg out of nested position with respect to the second undercut surface and into hooking engagement with the trailing edge of the plate for resiliently tensioning the plate for continuous automatic takeup as the cylinder rotates.

Claim 3

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring having a first leg presenting a tip in the form of a longitudinal edge opposite the undercut surface in position for bearing upon the leading edge of the plate and a second leg having an edge of hook cross section for underlying the inwardly bent trailing edge of the plate, a manually rotatable cam shaft extending along the length of the U-shaped spring on the trailing edge side of the slot and having a longitudinal raised portion for applying force to the central portion of the second leg thereby to move the hooked edge thereon into engagement with the trailing edgE of the plate, and means including a force-transmitting member interposed between the two legs for transmitting force from the second leg to the first so that the tip of the first leg is brought into engagement with the leading edge of the plate when the cam shaft is rotated.

Claim 4

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring having a first leg presenting a tip in the form of a longitudinal edge opposite the undercut surface in position for bearing upon the leading edge of the plate and a second leg having an edge of hook cross section for underlying the inwardly bent trailing edge of the plate, a manually rotatable cam shaft extending along the length of the U-shaped spring on the trailing edge side of the slot and having a longitudinal raised portion for applying force to the central portion of the second leg thereby to move the hooked edge thereon into engagement with the trailing edgE of the plate, and means including a force-transmitting member interposed between the two legs for transmitting force from the second leg to the first so that the tip of the first leg is brought into engagement with the leading edge of the plate when the cam shaft is rotated.

Claim 5

The combination as claimed in claim 3 in which the force-transmitting member is in the form of a spring plate having a portion bent out of the plane thereof for normally (filling up) bridging substantially the entire gap between the first and second legs so that inward movement of the second leg brought about by the cam causes force to be transmitted from the second leg to the first leg for simultaneous movement of the two legs.

Claim 6

The combination as claimed in claim 3 in which the force-transmitting member is in the form of a spring plate of dogleg shape having a central bend generally aligned with the axis of the cam shaft for defining a region of concentration of applied force, the bend defining an upper portion dimensioned to extend into force-transmitting engagement adjacent the tip portion of the first leg of the U-shaped spring.

Claim 7

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring being in the form of a centrally bent plate of spring metal characterized by first and second legs spaced closely parallel to one another, said first leg presenting a longitudinal edge at its tip arranged opposite the undercut surface in a position for bearing upon the leading edge of the plate, said second leg having an edge for underlying said inwardly bent trailing edge and formed into a hook for hooking onto said trailing edge of the plate, means including a cam shaft having a flat thereon forming a substantial continuation of one of the walls of the slot but capable of projecting out into the slot for engagement of the second leg of the spring when the shaft is rotated thereby to apply tension to the hooked trailing edge of the plate, a helper spring in the form of a flat plate of spring metal bent at its central portion positioned between the legs of the U-shaped spring so that when the second leg is engaged by the cam, movement is transmitted from the second leg to the first leg so that the tip of the first leg engages the leading edge of the plate thereby to hold it captive against the undercut surface, and means mounted in the slot for holding the U-shaped spring and helper spring seated in the bottom of the slot.

Claim 8

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring being in the form of a centrally bent plate of spring metal characterized by first and second legs spaced closely parallel to one another, said first leg presenting a longitudinal edge at its tip arranged opposite the undercut surface in a position for bearing upon the leading edge of the plate, said second leg having an edge for underlying said inwardly bent trailing edge and formed into a hook for hooking onto said trailing edge of the plate, means including a cam shaft having a flat thereon forming a substantial continuation of one of the walls of the slot but capable of projecting out into the slot for engagement of the second leg of the spring when the shaft is rotated thereby to apply tension to the hooked trailing edge of the plate, a helper spring in the form of a flat plate of spring metal bent at its central portion positioned between the legs of the U-shaped spring so that when the second leg is engaged by the cam, movement is transmitted from the second leg to the first leg so that the tip of the first leg engages the leading edge of the plate thereby to hold it captive against the undercut surface, and means mounted in the slot for holding the U-shaped spring and helper spring seated in the bottom of the slot.

Claim 9

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring having a first leg presenting a tip in the form of a longitudinal edge opposite the undercut surface in position for bearing upon the leading edge of the plate and a second leg having an edge for underlying said inwardly bent trailing edge and formed into hook shape for hooking onto said trailing edge of the plate, a cam shaft extending along the length of the U-shaped spring on the trailing edge side of the slot for applying force to the central portion of the second leg thereby to engage the hook with the trailing edge of the plate, means including a longitudinally extensive force-transmitting member in the form of a spring plate interposed between the two legs for transmitting force from the second leg to the first so that the tip of the first leg is brought into engagement with the leading edge of the plate when the cam is actuated, the spring plate being longitudInally coextensive with the U-shaped spring, the spring and plate being notched at the ends to form aligned ledges, and a blocking member registered with the slot for blockingly engaging the ledges on the plate and spring for holding the latter in seated position in the groove against centrifugal dislodgement as the cylinder rotates.

Claim 10

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges, the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring having a first leg presenting a tip in the form of a longitudinal edge opposite the undercut surface in position for bearing upon the leading edge of the plate and a second leg having an edge for underlying said inwardly bent trailing edge and formed into hook shape for hooking onto said trailing edge of the plate, a cam shaft extending along the length of the U-shaped spring on the trailing edge side of the slot for applying force to the central portion of the second leg thereby to engage the hook with the trailing edge of the plate, means including a longitudinally extensive force-transmitting member in the form of a spring plate interposed between the two legs for transmitting force from the second leg to the first so that the tip of the first leg is brought into engagement with the leading edge of the plate when the cam is actuated, the spring plate being longitudInally coextensive with the U-shaped spring, the spring and plate being notched at the ends to form aligned ledges, and a blocking member registered with the slot for blockingly engaging the ledges on the plate and spring for holding the latter in seated position in the groove against centrifugal dislodgement as the cylinder rotates.

Claim 11

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot having a first undercut surface along the edge corresponding to the leading edge of said plate as regards the direction of rotation of said cylinder, for seating the inwardly bent leading edge of the plate, a second undercut surface provided along the trailing edge of said slot, a longitudinally extensive U-shaped spring having a first leg presenting a longitudinal edge adjacent the said first undercut surface and a second leg having a longitudinal edge formed into hook cross section and disposed between the said second undercut surface and the inwardly bent trailing edge of the plate, a rockable shaft extending the length of the U-shaped spring along the trailing edge side of the slot, said shaft having a camming surface thereon for projection from the plane of said trailing side to engage said second leg whereby upon rotation of said shaft the said second leg is forcibly displaced in a direction opposite the direction of rotation of said cylinder to engage the inwardly bent trailing edge of the plate and exert a constant tension thereon, and means for transmitting the motion of said second leg to said first leg whereby the longitudinal edge of the first leg is brought to bear against the inwardly bent leading edge of the plate.

Claim 12

In a plate lockup for a thin printing plate having inwardly bent leading and trailing edges the combination comprising a plate cylinder having an axially extending radial slot formed in the surface thereof, said slot having a first undercut surface along the edge corresponding to the leading edge of said plate as regards the direction of rotation of said cylinder, for seating the inwardly bent leading edge of the plate, a second undercut surface provided along the trailing edge of said slot, a longitudinally extensive U-shaped spring having a first leg presenting a longitudinal edge adjacent the said first undercut surface and a second leg having a longitudinal edge formed into hook cross section and disposed between the said second undercut surface and the inwardly bent trailing edge of the plate, a rockable shaft extending the length of the U-shaped spring along the trailing edge side of the slot, said shaft having a camming surface thereon for projection from the plane of said trailing side to engage said second leg whereby upon rotation of said shaft the said second leg is forcibly displaced in a direction opposite the direction of rotation of said cylinder to engage the inwardly bent trailing edge of the plate and exert a constant tension thereon, and means for transmitting the motion of said second leg to said first leg whereby the longitudinal edge of the first leg is brought to bear against the inwardly bent leading edge of the plate.

Claim 13

In a plate lockup assembly, the combination comprising a thin printing plate having inwardly bent leading and trailing edges, a plate cylinder having an axially extending radial slot formed in the surface thereof, the slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring characterized by first and second legs spaced closely parallel to each other, said first leg presenting a longitudinal edge at its tip opposite the undercut surface in position for bearing upon the inwardly bent leading edge of the plate and a second leg having a longitudinal edge formed into hook cross section for underlying the inwardly bent trailing edge of the plate, the inwardly bent trailing edge of the plate being bent into Z formation to provide a lip for snapping over the edge of hook cross section when the plate is installed, the edge of the first leg being bent in the same direction as the edge on the second leg for engagement by the trailing edge during insertion of the plate to guide it into its snapped position, means including a longitudinally extending spring actuating cam at the trailing edge side of the slot for applying force to the central portion of the second leg thereby to move the edge of hook cross section into resilient engagement with the snapped in place trailing edge of the plate, and force-transmitting means bridging the space between the legs so that said movement of said second leg causes the tip of the first leg to be brought to bear against the leading edge of the plate to hold it captively seated against said undercut surface.

Claim 14

In a plate lockup assembly, the combination comprising a thin printing plate having inwardly bent leading and trailing edges, a plate cylinder having an axially extending radial slot formed in the surface thereof, the slot defining an undercut surface for seating the inwardly bent leading edge of the plate, a longitudinally extensive U-shaped spring seated in the slot, said U-shaped spring characterized by first and second legs spaced closely parallel to each other, said first leg presenting a longitudinal edge at its tip opposite the undercut surface in position for bearing upon the inwardly bent leading edge of the plate and a second leg having a longitudinal edge formed into hook cross section for underlying the inwardly bent trailing edge of the plate, the inwardly bent trailing edge of the plate being bent into Z formation to provide a lip for snapping over the edge of hook cross section when the plate is installed, the edge of the first leg being bent in the same direction as the edge on the second leg for engagement by the trailing edge during insertion of the plate to guide it into its snapped position, means including a longitudinally extending spring actuating cam at the trailing edge side of the slot for applying force to the central portion of the second leg thereby to move the edge of hook cross section into resilient engagement with the snapped in place trailing edge of the plate, and force-transmitting means bridging the space between the legs so that said movement of said second leg causes the tip of the first leg to be brought to bear against the leading edge of the plate to hold it captively seated against said undercut surface.