Sheet feeder, feed roller system and method

Abstract

A sheet feed roller system for reversing the sheet contact side of a sheet feed mechanism for an offset printing press. A traction roller is attached to a pivot shaft in the place of an idler roller. A non-traction roller is attached in the place of a drive roller. A transmission is provided having a rotary input connectable to the press for receiving rotational power from the press and having a rotary output. A variant axes drive mechanism with a first end and a second end is constructed so that the first end couples to the rotary output of the transmission. A power roller is attached and coupled to the second end of the variant axes drive mechanism and so that it pivots with the pivot shaft and remains in rotational contact with the traction roller to impart rotational power to the traction roller. The power roller and the traction roller pivot together about the pivot shaft toward and away from contact with the non-traction roller so that a sheet to be fed is engaged between the traction roller and the non-traction roller and is propelled into the printing press by rolling contact with the traction roller.

1 . A replacement sheet feeder for changing the rolling contact traction side of a sheet to be fed in an existing sheet feed mechanism for an existing offset printing press of the type having a drive roller for driving rolling traction contact with one side of the sheet to be fed and an existing idler roller pivotable about an existing pivot shaft toward and away from the drive roller, the replacement sheet feeder comprising: 
 a non-traction roller sized and constructed for installation in place of the existing drive roller;    a traction roller sized and constructed for installation in place of the existing idler roller; and    a traction roller power source operatively installed to provide rotation to the traction roller during pivoting so that the traction roller receives rotational power when it contacts a sheet to be fed on a side of the sheet to be fed opposite from the non-traction roller.    
   
   
       2 . The sheet feeder of  claim 1 , wherein the power source comprises: 
 a transmission attachable to the existing offset printing press having a rotary input in a position for receiving rotational power in a given direction from the offset printing press, the transmission having a rotary output;    a variant axes drive mechanism having first and second ends that rotate in the same rotational direction about first and second axes that are variable during rotation, the first end constructed to be coupled to the rotary output of the transmission;    a power roller coupled to the second end of the variant axes drive mechanism, the power roller mountable to the existing pivot shaft so that it is positioned in rotational contact with the traction roller when the traction roller is installed in place of the existing idler roller to impart rotational power from the power roller to the traction roller, wherein the installed traction roller is pivotable toward and away from contact with the installed non-traction roller to thereby contact a sheet to be fed between the traction roller and the non-traction roller to thereby propel the sheet to be fed into the press through rolling traction contact on the traction roller side of the sheet to be fed.    
   
   
       3 . The sheet feeder of  claim 2  wherein the variant axes drive mechanism comprises a variant axes positive drive.  
   
   
       4 . The sheet feeder of  claim 3  wherein the variant axes positive drive comprises a knuckle shaft.  
   
   
       5 . The sheet feeder of  claim 4  wherein the variant axes positive drive comprises 
 a first coupler having a first socket with a first slot;    a second coupler having a second socket and a second slot,    a knuckle shaft having a first boss at one end of the knuckle shaft for slip fit engagement in the first socket and a first bearing surface projecting from the first boss for engagement in the first slot and having a second boss at another end of the knuckle shaft for slip fit engagement in the second socket and a second bearing surface projecting from the second boss for engagement in the second slot, wherein the first and second bosses pivot relative the first and second couplers while the bearings surfaces engage against the first and second slots to transmit rotational power through the knuckle shaft.    
   
   
       6 . The sheet feeder of  claim 4  wherein the variant axes positive drive comprises: 
 a U-joint having a first and second coupler on either end.    
   
   
       7 . The sheet feeder of  claim 4  wherein the variant axes drive mechanism comprises a flexible drive shaft.  
   
   
       8 . The sheet feeder of  claim 7  wherein the flexible drive shaft comprises: 
 a coil metal spring encased in polymeric tubing;    a first coupler formed at one end of the flexible shaft;    a second coupler formed at another end of the flexible shaft, so that the first and second couplers are rotatable about variable axes through flexure of the coiled spring and polymeric tubing.    
   
   
       9 . The sheet feeder of  claim 2  wherein the variant axes drive mechanism comprises a variant axes positive drive.  
   
   
       10 . The sheet feeder of  claim 1  wherein the non-traction roller comprises at least one non-traction rolling surface formed on a metal shaft.  
   
   
       11 . The sheet feeder of  claim 10  wherein the at least one non-traction rolling surface formed on a metal non-traction shaft comprises at least one smooth cylindrical metal surface formed coaxially along a portion of the metal.  
   
   
       12 . The sheet feeder of  claim 1  wherein the traction roller comprises at least one traction rolling surface formed on a metal traction shaft.  
   
   
       13 . The sheet feeder of  claim 12  wherein the traction rolling surface formed on a metal comprises at least one cylindrically shaped polymeric surface coaxially attached along a portion of the metal shaft.  
   
   
       14 . The sheet feeder of  claim 2  wherein the power roller comprises a rotatable shaft having a polymeric traction surface formed thereon, the rotatable shaft mounted through bracket and journal bearings to a mounting plate in a position with the power roller parallel to the traction roller, wherein the mounting plate is attachable to the existing pivot shaft adjacent to the so that the power roller remains engaged with the traction roller when the traction roller is pivoted on the pivot shaft.  
   
   
       15 . The sheet feeder of  claim 14  further comprising: 
 a pivot connection between the journalled bracket rotatably holding the power roller and the mounting plate;    a basing device interposed between the mounting plate and the journalled bracket operatively connected to bias the bracket and thereby to bias the power roller into rolling contact with the traction roller; and    a lockdown device connecting between the bracket and the mounting plate having a locked down position holding the bracket so that the power roller is pulled away from the traction roller against the biasing device and having a release position allowing the biasing device to bias the power roller into rolling contact with traction roller.    
   
   
       16 . A sheet feed roller system for inverting the rolling contact side of a sheet feed mechanism for an offset printing press of the type including a drive roller operatively coupled to the offset printing press through a rotary power receiving mechanism for receiving rotational power in a given direction to rotate the drive roller, an idler roller mounted above the drive roller on a pivot shaft, and the pivot shaft operatively connected for timed alternating pivoting of the idler roller downward toward the drive roller and upward away from the drive roller so that a sheet to be fed into the press when placed overlaying the drive roller can be pushed down by the pivoted idler roller against a top side of the sheet so that a bottom side contacts against the drive roller so that the sheet to be fed is caused to be linearly propelled into the press by rolling contact with the drive roller on the bottom side of the sheet to be fed, the sheet feed roller system for inverting the rolling contact side comprising: 
 a non-traction roller installed in place of the drive roller in a position below a sheet to be fed into the printing press;    a traction roller installed on the pivot shaft in place of the idler roller for alternating pivoting toward and away from the non-traction roller; and    a traction roller power source operatively connected to provide rotation to the traction roller during pivoting so that the traction roller is rotating when it is pivoted into contact with a sheet to be fed on the top side of the sheet to be fed opposite from the non-traction roller below the sheet to be fed.    
   
   
       17 . The sheet feed system of  claim 16  wherein the traction roller power source comprises: 
 a transmission having a rotary input positioned for receiving rotational power from the printing press and having a rotary power output;    a variant axes positive drive mechanism having a first end and a second end, the first end constructed for coupling to the rotary power output of the transmission;    a power roller constructed to be coupled to the second end of the variant axes drive mechanism and mountable to the pivot shaft in rotational contact with the traction roller to impart rotational power from the power roller to the traction roller and so that the power roller and the traction roller pivot together about the pivot shaft toward and away from contact with the non-traction roller so that non-traction roller receives rotational power when contacting the sheet to be fed and the sheet to be fed is propelled into the press by rolling contact with the traction roller.    
   
   
       18 . A sheet feeder for a printing press of the type for printing on one side of a sheet, the sheet feeder comprising: 
 a non-traction roller installed in a position below that a staging position of sheet to be fed into the printing press, wherein the non-traction roller is adjacent to a side of the sheet that is not the side to be printed;    a traction roller installed on a pivot shaft parallel to and spaced vertically above the non-traction roller and above the staging position of a sheet to be fed, wherein the pivot shaft is actuated by the press for alternating pivoting the traction roller toward and away from the non-traction roller and for contacting the side of the sheet that is the side to be printed;    a transmission having a rotary input positioned for receiving rotational power from the press and having a rotary output rotated in response to rotation of the rotary input;    a variant axes positive drive mechanism having a first end and a second end, the first end coupled to the rotary output of the transmission;    a power roller having a rolling traction surface, the power roller coupled to the second end of the variant axes drive mechanism and mounted to the pivot shaft so that the rolling traction surface is in rolling contact with the traction roller to impart rotational power from the power roller to the traction roller and so that the power roller and the traction roller pivot together about the pivot shaft toward and away from the non-traction roller so that the sheet is propelled with rolling contact on the traction roller on top of the side of the sheet that is the side to be printed.    
   
   
       19 . A method for changing the rolling contact traction side of a sheet to be fed in an existing sheet feed mechanism for an existing offset printing press of the type having a drive roller for driving rolling traction contact with one side of the sheet to be fed and an existing idler roller pivotable about an existing pivot shaft toward and away from the drive roller, the replacement sheet feeder comprising: 
 removing and existing drive roller and installing a non-traction roller in place of the removed existing drive roller;    removing an existing idler roller and installing a traction roller in place of the removed existing idler roller; and    installing a power source for the traction roller operatively connected to the press and the traction roller to provide rotation to the traction roller during pivoting so that the traction roller receives rotational power when it contacts a sheet to be fed on a side of the sheet to be fed opposite from the non-traction roller.    
   
   
       20 . The method of  claim 19 , wherein the installing the power source for the traction roller comprises: 
 installing a transmission attached to the existing offset printing press, the transmission having a rotary input in a position for receiving rotational power from the offset printing press and the transmission having a rotary output;    installing a variant axes drive mechanism having first and second ends that rotate in the same rotational direction about first and second axes that are variable during rotation, the first end constructed to be coupled to the rotary output of the transmission;    installing a power roller coupled to the second end of the variant axes drive mechanism, the power roller mounted to the existing pivot shaft so that it is positioned in rotational contact with the traction roller when the traction roller is installed in place of the existing idler roller to impart rotational power from the power roller to the traction roller, wherein the installed traction roller is pivotable toward and away from contact with the installed non-traction roller to thereby contact a sheet to be fed between the traction roller and the non-traction roller to thereby propel the sheet to be fed into the press through rolling traction contact on the traction roller side of the sheet to be fed.