Web bending fixture

Abstract

A web bending fixture to bend lithographic plates used in web offset printing and production. Precise bends are created by a precision machine tool fixture. The fixture utilizes continuously supported eccentric camming members, one on each end of the fixture, each supported by a plurality of split bearings within which the camming members rotate. After the lithographic plate is precisely aligned with unique registration means and immobilized, the camming members, are moved into position and, rotating within the bearings, form the leading and trailing edges of the plate around precisely positioned and fixed anvils.

I claim as my invention: 
     
       1. A web bending fixture for bending plates of metal having a leading edge and a trailing edge comprising: a bed to support the plate to be bent;   at least one anvil having a bending radius at the edge of the bed;   at least one eccentric camming member having a bending surface positioned relative to the anvil to bend one of the edges of the plate around the bending radius of the anvil;   a full bearing supporting each end of the eccentric camming member for rotation;   a plurality of additional bearings intermediate the ends of the eccentric camming member within which the eccentric camming member is rotatably contained during rotation, the additional bearings being spaced along the length of the eccentric camming member to radially support the eccentric camming member throughout its length; and   means for rotating the eccentric camming member around the bending radius of the anvil, the closest point on the bending surface of the eccentric camming member being spaced from the anvil at all times during rotation a distance equivalent to the thickness of the plate being bent.   
     
     
       2. The web bending fixture of claim 1 wherein two anvils are provided, at opposing ends of the bed, to bend both the leading edge and the trailing edge of the plate and wherein an eccentric camming member is positioned adjacent each anvil to form both the leading edge and the trailing edge of the plate, each eccentric camming member having a bending surface, the closest point on which is spaced from the adjacent anvil during bending a distance equivalent to the plate being bent. 
     
     
       3. The web bending fixture of claim 2 wherein one of the anvils is retractable for purposes of removing the plate from the bed of the web bending fixture. 
     
     
       4. The web bending fixture of claim 1 further comprising means to position the plate on the bed of the web bending fixture. 
     
     
       5. The web bending fixture of claim 4 wherein the means to position the plate comprise apertures in the bed of the web bending fixture through which air is passed to provide an air cushion upon which the plate can ride during positioning. 
     
     
       6. The web bending fixture of claim 4 wherein the means to position the plate comprise a plurality of limit switches to determine when the plate is in position. 
     
     
       7. The web bending fixture of claim 6 wherein at least three limit switches are utilized to position the plate on the bed of the web bending fixture. 
     
     
       8. The web bending fixture of claim 4 wherein the plate has a plurality of registration holes prepunched in the plate before bending and wherein the means to position the plate prior to bending comprise registration pin mechanisms having registration pins for insertion into the registration holes. 
     
     
       9. The web bending fixture of claim 8 wherein at least two registration pin mechanisms are utilized to locate and fix the plate relative to two registration holes. 
     
     
       10. The web bending fixture of claim 8 wherein at least three registration pin mechanisms are utilized, two on one edge of the plate and one on the opposing edge of the plate to precisely position the plate relative to the bends to be made by the web bending fixture. 
     
     
       11. The web bending fixture of claim 8 further comprising: an end plate on each end of the eccentric camming member containing the full bearings which support each end of the eccentric camming member for rotation;   a header bar secured between the end plates; and   wherein each registration pin mechanism comprises: a registration pin having a rounded tip for insertion into the registration hole;   means for inserting and withdrawing the registration pin into and out of the registration hole;   a block fixed to the bed adjacent the registration hole in the plate;   a set of containment fingers for straddling the registration hole above the plate and being slidably mounted in the block;   a ramp mechanism secured to the containment fingers slidably movable therewith and positioned above the containment fingers;   positioning means attached to the header bar above the ramp mechanism, said header bar and positioning means being vertically movable so that the positioning means when moved downwardly engages the ramp to slide it and the associated containment fingers rearwardly away from the registration hole and edge of the plate; and   biasing means attached to the block and to the containment fingers and associated ramp to bias the fingers and associated ramp toward the edge of the plate so that when the positioning means moves upwardly the containment fingers and associated ramp move forwardly toward the adjacent registration hole and edge of the plate.     
     
     
       12. The web bending fixture of claim 1 further comprising means to secure the plate to the bed of the web bending fixture prior to bending. 
     
     
       13. The web bending fixture of claim 12 wherein the means to secure the plate to the bed comprises apertures through the bed of the web bending fixture through which air is drawn to create a vacuum. 
     
     
       14. The web bending fixture of claim 12 wherein the means to secure the plate to the bed of the web bending fixture comprise clamp means to hold the plate to the bed of the web bending fixture. 
     
     
       15. The web bending fixture of claim 1 wherein the plurality of additional bearings are split bearings comprising upper bearings carried by upper bearing mounts and lower bearings carried by lower bearing mounts secured to the bed of the web bending fixture. 
     
     
       16. The web bending fixture of claim 15 wherein the upper bearing mounts and lower bearing mounts are secured together during the bending to provide the plurality of additional bearings, each additional bearing having a continuous bearing surface during the bending of the plate by the web bending fixture. 
     
     
       17. The web bending fixture of claim 16 further comprising: an end plate on each end of the eccentric camming member each end plate containing the full bearing supporting the end of the eccentric camming member;   a header bar secured between the end plates;   a first motive means connected to the end plates to vertically move the end plates and header bar upwardly and downwardly and wherein the upper bearing mounts are secured to the header bar so that when the end plates and header bar is moved downwardly the upper bearing mounts and lower bearing mounts are secured together to provide the continuous bearing surfaces.   
     
     
       18. The web bending fixture of claim 1 wherein at least four bearings are positioned intermediate the ends of the eccentric bending member to support the eccentric bending member during bending. 
     
     
       19. The web bending fixture of claim 1 wherein six bearings are provided intermediate the ends of the eccentric bending member to support the eccentric bending member during bending. 
     
     
       20. The web bending fixture of claim 1 further comprising: an end plate on each end of the eccentric camming member;   a header bar secured between the end plates;   a plurality of upper split bearing mounts having upper bearing surfaces secured to the header bar;   a plurality of lower split bearing mounts having lower bearing surfaces secured to the bed;   means for slidably attaching the end plates to the bed of the web bending fixture;   clamp means operatively secured to the header bar;   first motive means connected to the end plates to slide the clamp means into engagement with the plate to clamp the plate to the bed of the web bending fixture and to slide the upper split bearing mounts into a secured engagement with the lower split bearing mounts to provide the plurality of additional bearings and so that a plurality of continuous bearing surfaces are provided to support the eccentric camming member during rotation; and   second motive means connected to the means for rotating the eccentric camming member so that a bend is formed in the edge of the plate.   
     
     
       21. The web bending fixture of claim 20 wherein the first motive means comprises a set of cylinders, one associated with each end plate and connected to raise and lower the end plate. 
     
     
       22. The web bending fixture of claim 20 wherein the means for rotating the eccentric camming member comprises a rack and pinion gear on each end of the eccentric camming member. 
     
     
       23. The web bending fixture of claim 22 wherein a rack is slidably mounted on each end plate. 
     
     
       24. The web bending fixture of claim 23 wherein the second motive means comprises a set of cylinders, one on each end of the eccentric camming member and mounted on each end plate and connected to each rack so that when the racks are moved they rotate the associated pinion gears. 
     
     
       25. The web bending fixture of claim 20 further comprising means for retracting the anvil after a bend is formed in the plate so that the plate can be removed from the web bending fixture. 
     
     
       26. The web bending fixture of claim 25 wherein the anvil is slidably attached to the bed and movable between a bending position and a retracted position and wherein the means for retracting the anvil comprise: a set of three vertically movable cams positioned behind the anvil so that when in their upward position they slide the anvil forward to the bending position and when in their downward position allow the anvil to retract;   third motive means connected to the cams to move the cams up to slide the anvil to the bending position and to move the cams down so the anvil can be retracted; and   biasing means between the bed and the anvil to retract the anvil when the cams are moved by the motive means to the downward position.   
     
     
       27. A web bending fixture for bending plates of metal having an image thereon and a leading edge and a trialing edge comprising: a bed to support the plate to be bent;   two anvils at opposing ends of the bed, each having a bending radius at the edge of the bed;   a set of two eccentric camming members, one associated with each anvil, each eccentric camming member having a bending surface positioned relative to the adjacent anvil to bend one of the edges of the plate around the bending radius of the anvil;   two sets of end plates, one set associated with each eccentric camming member to provide an end plate on each end of each of the eccentric camming members, each end plate having a full bearing mounted therein for supporting the end of the eccentric camming member with which it is associated for rotation;   a header bar secured between each of the two sets of end plates;   a plurality of upper split bearing mounts having upper bearing surfaces secured to each header bar;   a plurality of lower split bearing mounts having lower bearing surfaces secured to the bed below each header bar;   means for slidably attaching the end plates to the bed of the web bending fixture in a manner that they can be moved upwardly and downwardly;   means for positioning a plate on the bed;   means for aligning the plate on the bed so that the image on the plate is in registration with the bends to be formed in the plate;   clamp means operatively secured to each header bar;   a first set of four cylinders, one connected to each end plate to vertically move the end plates downwardly so that the clamp means clamp the leading edge and trailing edge of the plate to the bed of the web bending fixture and so that the upper split bearing mounts are moved into a secured engagement with the lower split bearing mounts to provide a plurality of additional bearings intermediate the ends of each of the eccentric camming members each of the plurality of additional bearings having a continuous bearing surface when secured together to support each eccentric camming member throughout its length during rotation;   means for rotating each of the eccentric camming members around the bending radius of the adjacent anvil so that the closest point on the bending surface of each eccentric camming member is spaced from the adjacent anvil at all times during rotation a distance equivalent to the thickness of the plate being bent, said means for rotating the eccentric camming member comprising:   a rack and pinion gear associated with each end of each eccentric camming member; and   a second set of four cylinders, one on each end plate and connected to the racks to slidably move each rack in a downward direction so that the associated pinion gears rotate the eccentric camming members so that a bend is formed in the leading edge and the trailing edge of the plate; and means for removing the formed plate from the fixture. .Iadd.   
     
     
       28.  A web bending fixture for bending plates of metal having a leading edge and trailing edge comprising: a bed to support the plate to be bent;   at least one anvil having a bending radius at the edge of the bed;   at least one eccentric camming member having a bending surface positioned relative to the anvil to bend one of the edges of the plate around the bending radius of the anvil;   a full bearing supporting each end of the eccentric camming member for rotation:   at least one additional bearing intermediate the ends of the eccentric camming member within which the eccentric camming member is rotatably contained during rotation, supporting radially the eccentric camming member intermediate its length; and   means for rotating the eccentric camming member around the bending radius of the anvil, the closest point on the bending surface of the eccentric camming member being spaced from the anvil at all times during rotation a distance equivalent to the thickness of the plate being bent. .Iaddend. .Iadd.   
     
     
       29.  The web bending fixture of claim 28 wherein the additional bearing comprises a split bearing having an upper bearing carried by an upper bearing mount and a lower bearing carried by a lower bearing mount secured to the bed of the web bending fixture. .Iaddend.