Log positioning device and method

Abstract

A method of positioning a log of sheet material includes sensing the presence of a log in a staging area having a length, a midpoint at the center of the length, and a boundary point between the midpoint and an end of the length; sensing the presence or absence of a portion of the log at the boundary point; and moving the log along the length of the staging area. When the log is present in both the staging area and at the boundary point, the log is moved toward the midpoint. When the log is present in the staging area and absent from the boundary point, the log is moved toward the boundary point.

1 . A method of positioning a log of sheet material, comprising: 
 sensing the presence of a log in a staging area, the staging area comprising a length, a midpoint at the center of the length, and a boundary point between the midpoint and an end of the length;    sensing the presence or absence of a portion of the log at the boundary point; and    positioning the log relative to the boundary point.    
     
     
         2 . The method of  claim 1 , wherein, when the log is present in both the staging area and at the boundary point, the positioning comprises moving the log along the length of the staging area toward the midpoint until the log is absent from the boundary point.  
     
     
         3 . The method of  claim 1 , wherein, when the log is present in the staging area and is absent from the boundary point, the positioning comprises moving the log along the length of the staging area toward the boundary point until the log is present at the boundary point.  
     
     
         4 . The method of  claim 1 , wherein the staging area comprises a conveyor belt, and the positioning further comprises cycling the conveyor belt.  
     
     
         5 . The method of  claim 1 , further comprising providing the log in the staging area prior to sensing the presence of the log in the staging area.  
     
     
         6 . The method of  claim 1 , further comprising releasing the log from the staging area after positioning the log relative to the boundary point.  
     
     
         7 . The method of  claim 1 , wherein the sensing the presence of the log in the staging area comprises measuring a status of a switch.  
     
     
         8 . The method of  claim 1 , wherein the sensing the presence of the log in the staging area comprises measuring a mass of a substance in the staging area.  
     
     
         9 . The method of  claim 1 , wherein the sensing the presence of the log in the staging area comprises measuring a signal from an ultrasonic sensor.  
     
     
         10 . The method of  claim 1 , wherein the sensing the presence of the log in the staging area comprises measuring a signal from an optical sensor.  
     
     
         11 . The method of  claim 1 , wherein the sensing the presence or absence of a portion of the log at the boundary point comprises measuring a status of a switch.  
     
     
         12 . The method of  claim 1 , wherein the sensing the presence or absence of a portion of the log at the boundary point comprises measuring a mass of a substance at the boundary point.  
     
     
         13 . The method of  claim 1 , wherein the sensing the presence or absence of a portion of the log at the boundary point comprises measuring a signal from an ultrasonic sensor.  
     
     
         14 . The method of  claim 1 , wherein the sensing the presence or absence of a portion of the log at the boundary point comprises measuring a signal from an optical sensor.  
     
     
         15 . The method of  claim 14 , wherein the log comprises a center portion and an end portion, the center portion comprising a width edge, and the optical sensor having a focal point which is positioned past the width edge.  
     
     
         16 . The method of  claim 15 , wherein the focal point is positioned from about 1 millimeter to about 20 millimeters past the width edge.  
     
     
         17 . The method of  claim 15 , wherein the focal point is positioned from about 2 millimeters to about 10 millimeters past the width edge.  
     
     
         18 . The method of  claim 15 , wherein the optical sensor has a focal window comprising the focal point.  
     
     
         19 . The method of  claim 15 , wherein the end portion has a uniform width equal to the width of the center portion.  
     
     
         20 . The method of  claim 15 , wherein the end portion has a non-uniform width.  
     
     
         21 . The method of  claim 1 , wherein the log comprises a wetting solution add-on of at least 25%.  
     
     
         22 . A method of positioning a plurality of logs of sheet material, comprising: 
 providing a single log in a staging area, the staging area comprising a length, a midpoint at the center of the length, and a boundary point between the midpoint and an end of the length;    sensing the presence or absence of a portion of the log at the boundary point;    positioning the log relative to the boundary point;    releasing the log from the staging area; and    repeating the providing, sensing, positioning and releasing.    
     
     
         23 . The method of  claim 22 , wherein the positioning comprises moving the log along the length of the staging area toward the midpoint when the log is present at the boundary point.  
     
     
         24 . The method of  claim 22 , wherein the positioning comprises moving the log along the length of the staging area toward the boundary point when the log is absent from the boundary point.  
     
     
         25 . The method of  claim 22 , wherein the providing comprises sensing the presence of the log in the staging area.  
     
     
         26 . The method of  claim 22 , wherein the length of the staging area is at least as long as an average length of a plurality of logs.  
     
     
         27 . The method of  claim 22 , wherein the providing comprises dispensing the single log from a storage area comprising a plurality of logs.  
     
     
         28 . The method of  claim 22 , wherein the providing comprises dispensing the single log from a log forming apparatus.  
     
     
         29 . The method of  claim 28 , wherein the log forming apparatus is an apparatus for wetting and winding a sheet of material.  
     
     
         30 . The method of  claim 22 , wherein the providing comprises transporting the single log toward the staging area and depositing the single log in the staging area.  
     
     
         31 . The method of  claim 30 , wherein the transporting comprises dispensing the single log onto a conveyor.  
     
     
         32 . The method of  claim 22 , wherein at least 10 logs are positioned each minute.  
     
     
         33 . The method of  claim 22 , wherein at least 20 logs are positioned each minute.  
     
     
         34 . The method of  claim 22 , wherein at least 30 logs are positioned each minute.  
     
     
         35 . The method of  claim 22 , wherein the sensing the presence or absence of a portion of the log at the boundary point comprises a member selected from the group consisting of measuring a status of a switch, measuring a mass of a substance at the boundary point, measuring a signal from an ultrasonic sensor, and measuring a signal from an optical sensor.  
     
     
         36 . The method of  claim 25 , wherein the sensing the presence of the log in the staging area comprises a member selected from the group consisting of measuring a status of a switch, measuring a mass of a substance in the staging area, measuring a signal from an ultrasonic sensor, and measuring a signal from an optical sensor.  
     
     
         37 . A method of positioning a wet log of sheet material, comprising: 
 sensing the presence of a wet log in a staging area by measuring a signal from a first optical sensor, the staging area comprising a length, a midpoint at the center of the length, a boundary point between the midpoint and an end of the length, and a conveyor belt;    sensing the presence or absence of a portion of the wet log at the boundary point by measuring a signal from a second optical sensor; and    moving the wet log along the length of the staging area by cycling the conveyor belt, the moving the wet log comprising cycling the wet log toward the midpoint until the wet log is absent from the boundary point, when the wet log is present in both the staging area and at the boundary point; or cycling the wet log toward the boundary point until the wet log is present at the boundary point, when the wet log is present in the staging area and is absent from the boundary point.    
     
     
         38 . An apparatus for positioning a log of sheet material, comprising: 
 a staging area comprising a length, a midpoint at the center of the length, and a boundary point between the midpoint and an end of the length;    a first sensor positioned to detect the presence or absence of the log in the staging area;    a second sensor positioned to detect the presence or absence of a log at the boundary point; and    a conveyor belt positioned to cycle along the length of the staging area.    
     
     
         39 . The apparatus of  claim 38 , wherein the first sensor comprises an optical sensor having a field of view along the length of the staging area.  
     
     
         40 . The apparatus of  claim 38 , wherein the second sensor comprises an optical sensor having a focal point at the boundary point.  
     
     
         41 . The apparatus of  claim 40 , wherein, when a log comprising a width edge is in the staging area, the focal point is positioned past the width edge.  
     
     
         42 . The apparatus of  claim 38 , wherein, when the first sensor detects the presence of a log in the staging area and the second sensor detects the presence of a portion of the log at the boundary point, the conveyor belt cycles to move the log toward the midpoint until the log is absent from the boundary point.  
     
     
         43 . The apparatus of  claim 38 , wherein, when the first sensor detects the presence of a log in the staging area and the second sensor detects the absence of a portion of the log at the boundary point, the conveyor belt cycles to move the log toward the boundary point until the log is present at the boundary point.  
     
     
         44 . The apparatus of  claim 38 , wherein the staging area is connected to a log processing machine.  
     
     
         45 . The apparatus of  claim 38 , wherein the staging area is connected to a log forming machine.  
     
     
         46 . The apparatus of  claim 38 , further comprising a movable gate which can release the log from the apparatus.  
     
     
         47 . An apparatus for positioning a log of sheet material, comprising: 
 means for supporting a log;    means for detecting the presence or absence of a log on the supporting means;    means for detecting the presence or absence of a portion of the log at a boundary point; and    means for moving the log toward or away from the boundary point;    wherein, when the log is detected as present both on the supporting means and at the boundary point, the moving means moves the log away from the boundary point; and when the log is detected as present on the supporting means but absent from the boundary point, the moving means moves the log toward the boundary point.