Abstract:
The present invention provides a method and apparatus for pleating paper. The apparatus includes a pair of pleating rollers, means to rotate one of said pleating rollers, a first pair of support rollers in supporting contact with a first of said pair of pleating rollers and a second pair of support rollers in supporting contact with a second of said pair of pleating rollers. Each of said pleating rollers has a plurality of radially reduced sections. An elongated pleating finger member is positioned in at least a plurality of radially reduced sections, and means are provided to movably support each of said elongated pleating finger members.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of the subject matter of Provisional Patent Application No. 60/538,633, for a Pleating System, which was filed with the U.S. Patent and Trademark Office on Jan. 23, 2004. The entire disclosure and contents of the above application is hereby incorporated by reference. 
     
    
     GOVERNMENT INTEREST STATEMENT  
       [0002]     NONE  
       FIELD OF THE INVENTION  
       [0003]     The invention relates to a mechanism for high speed pleating, and more particularly, to an apparatus for the continuous high speed pleating of paper, such as Kraft paper, or the like.  
       SUMMARY  
       [0004]     According to a first broad aspect of the invention, there is provided an apparatus for pleating paper comprising, a pair of pleating rollers, means to rotate one of said pleating rollers, a first pair of support rollers in supporting contact with a first of said pair of pleating rollers and a second pair of support rollers in supporting contact with a second of said pair of pleating rollers. Each of said pleating rollers have a plurality of radially reduced sections and an elongated pleating finger member is supported for being positioned in at least a plurality of radially reduced sections.  
         [0005]     Means are provided to movably support each of said elongated pleating finger members. The elongated pleating fingers are parallel to each other and are selectably movable toward and away from each other to varying the height of pleats that are formed, and are movable toward and away from said pleating rollers. The elongated pleating fingers remain parallel to each other in all positions.  
         [0006]     Advantageously, the support rollers are offset from each other on the order of about 8 degrees. In an embodiment of the invention, the angle formed between a first line drawn through the center of a first support roller to the center of a pleating roller and a second line drawn through the center of each of said pleating rollers is about 4 degrees.  
         [0007]     The apparatus includes paper feed means for feeding paper, preferably Kraft paper, between the pleating rollers.  
         [0008]     In an embodiment of the invention, the pairs of elongated pleating fingers are spaced from each other by a distance that is approximately equal to the height of pleats produced by said apparatus for pleating paper.  
         [0009]     Each of the elongated pleating fingers has a radial region at its proximal end for providing a decreasing space between pleating fingers as paper enters the space between pairs of elongated pleating fingers. In a preferred embodiment of the invention, the radial region is rounded.  
         [0010]     In an embodiment of the invention pairs of elongated pleating fingers are spaced apart by a lesser amount at their proximal ends than at their distal ends. Additionally, pairs of elongated pleating fingers are spaced apart by a first distance along a first region at the elongated fingers proximal end, and are spaced apart by a second distance along a second region. The second region extends from the first region to the elongated pleating fingers&#39; distal end. In a preferred embodiment of the invention, the second distance is greater than the first distance,  
         [0011]     In another embodiment of the invention, a projection member is proximate the junction of said first region and said second region, and is movably supported to variably project into the space between the pairs of elongated pleating fingers. The projection member may project about 20 thousandths of an inch into the space between the pairs of elongate pleating fingers.  
         [0012]     In an embodiment of the invention the pleating rollers are formed of a deformable material and are substantially flattened in the region of contact between said pleating rollers. The material of the pleating rollers can be about 80-durometer hardness rubber and the rollers can have a steel core.  
         [0013]     In an embodiment of the invention a plurality of the radially reduced sections have a width of about 0.37 inches and the rollers have a first plurality of sections having a width of about 0.38 inches. A second plurality of sections has a width of about at least about one inch, and the rollers have a diameter of about 1.5 inches.  
         [0014]     In an embodiment of the invention the length from the proximal end to the second region is about one inch and the length of the second region is about 3.5 inches. The total length of the first region and said second region is up to about five inches.  
         [0015]     In an embodiment of the invention paper is pleated by feeding paper to a pair of pleating rollers. Drive means are provided to rotate one of said pleating rollers. A first of the pair of pleating rollers can be supported by a first pair of support rollers. A second of the pair of pleating rollers can be supported by a second pair of support rollers. Each of the pleating rollers has a plurality of radially reduced sections and an elongated pleating finger member is positioned in at least a plurality of radially reduced sections. Advantageously, each radially reduced section accommodates a pleating finger.  
         [0016]     In an embodiment of the invention each of the elongated pleating finger members are movable in order to adjust the distance between elongated pleating fingers by a predetermined amount and thereby producing pleats of a corresponding predetermined height.  
         [0017]     The process is initiated by unwinding Kraft paper from a continuous roll, feeding the Kraft paper to said pleating rollers and withdrawing pleated paper from said elongated pleating fingers.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The invention will be described in conjunction with the accompanying drawings, in which:  
         [0019]      FIG. 1  is a schematic fragmentary illustration of a pleating mechanism in accordance with the present invention.  
         [0020]      FIGS. 2 and 2   a  are fragmentary illustrations of the pleating rollers, partly in cross-section;  
         [0021]      FIG. 3  is a fragmentary illustration of the pleating rollers, partly in cross-section, and showing pleats formed by the pleating rollers in accordance with an embodiment of the present invention;  
         [0022]      FIG. 4  is a schematic illustration of a pair of pleat rollers driving a sheet of paper in accordance with an embodiment of the present invention;  
         [0023]     FIG,  5  is an enlarged view of the pleating region in accordance with an embodiment of the present invention;  
         [0024]      FIG. 6  illustrates the use a pleating operation in which the pleating starts prematurely.  
         [0025]      FIG. 7  is a schematic illustration of a pleating operation in accordance with an embodiment of the present invention;  
         [0026]      FIG. 8  is a side schematic view of a pair of pleating fingers, in accordance with an embodiment of the present invention; and  
         [0027]      FIG. 9  side schematic view of the upper pleating finger of  FIG. 8 , showing the projection member projecting from the bottom of the pleating finger, in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0028]     It is advantageous to define several terms before describing the invention. It should be appreciated that the following definitions are used throughout this application.  
         [0000]     Definitions  
         [0029]     Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated.  
         [0030]     For the purposes of the present invention, the term “offset” as applied to the relationship between support rollers and pleating rollers, refers the angle formed between a first line drawn through the center of a first support roller to the center of a pleating roller and a second line drawn through the center of a second support roller to the center of the pleating roller. As the terms are herein employed, an offset of 8 degrees between a pair of support rollers is equivalent to an offset of 4 degrees for each roller.  
         [0031]     For the purposes of the present invention, the term “radial region” refers to a concave region, a rounded region, or a region having a tapered or gradually decreasing thickness.  
         [0032]     For the purposes of the present invention, the term “continuous roll” means sheet paper wound about a core, that is paper that encircles or spirals an interior core member.  
         [0000]     Description  
         [0033]     Pleating devices have been in commercial use for over a hundred years and pleated fabrics have been used for apparel. Pleated paper has been used for filters such as automotive oil, air and gasoline filter media.  
         [0034]     The use of pleated paper as a low cost, high volume void fill can be greatly enhanced if the paper can be repeated by a high-speed system that consistently produces pleats of a predetermined size. Pleat height is typically measured in terms of the normal distance, or right angle distance between a pair of parallel lines that touch the apices of the pleats. The hypotenuse of the pleat angle stays consistent but the apex angle and the pleat height can vary. The use of pleated Kraft paper for a void filter or pleated wrap material requires the formation of an acute angle and a sufficiently sharp crease at the apex to resist the migration of the pleats toward an obtuse angle. The system preferably generates pleats with an apex angle under 45 degrees, and more preferably, with an angle of less than 25 degrees.  
         [0035]     As shown in the embodiment of  FIG. 1 , the system, indicated generally as  100 , includes a pair of counter-rotating pleating rollers,  104  and  106 . The rollers are preferably about 80-durometer rubber mounted on a steel shaft  122  and  124  respectively. The durometer range may vary about +/−10%, but a variation of no greater than about +/−5% is preferred. The rollers can also be formed of other durable materials, such as steel. The backpressure generated by the pleating action is extremely high, and therefore it is desirable to use large diameter rollers in order to resist the bending or sagging of the rollers. However, it has now been found that the reliability and consistency of the pleating action can be greatly improved through the use of a small diameter roller. It can be desirable to produce pleated paper in 48-inch widths and thus the rollers can bow when under the pressure of the pleating action. Each roller  104  and  106  is reinforced by a dual set of 2-inch diameter rollers  121 D,  121 C,  121 B and  121  respectively. The support rollers can be offset slightly upstream for the bottom support rollers and slightly downstream for the upper support rollers in order to counter the forward and backpressure created by the twisting action of the pleating rollers. The point of contact of the support roller and the pleating roller is preferably offset about four degrees thus generating a counterpressure indicated in respect to roller  106 , by arrow  140 . The angle is measured on the basis of a line drawn through the center of the two pleating rollers and a line drawn from the center of a pleating roller and the contact point between the pleating and support rollers. Roller rotation directions are indicated by arrows  142  and  120 .  
         [0036]     The pleating action is controlled or regulated by a pair of finger members  130  and  132  that are position in the key regions of the pleating rollers. The finger members are mounted such that the distance  136  between the fingers can be adjusted as indicated by arrows  133 , or in the opposite direction from the arrows. The pleat height is substantially equal to the distance  136 . If the pleat apices are crushed flat then the height is approximately equal to the distance between the pleat apices. The pleating action is facilitated by the use of a projection  118 , on the finger  130 . The fingers  130  and  132  are also adjustable forward and aft, that is, further into or out of the region between the rollers, as indicated by arrow  160 . The projection can be on either finger, and preferably is on only one finger.  
         [0037]     As illustrated in  FIG. 2 , the rollers  202  are spaced apart by a distance indicated as  208 . The width of the rollers is indicated by arrows  210 . The projection  206  on the finger  204  is preferably threaded such that it can project to a greater or lesser extent into the path of the pleats of the pleated paper.  
         [0038]     The embodiment of the invention, as illustrated in  FIG. 2   a,  shows spaces  220  between the rollers,  222  and  224 . The fingers are positioned in each of these spaces. In this embodiment, two narrow rollers  222  are positioned to alternate with wide rollers  224 .  
         [0039]     As illustrated in the embodiment of  FIG. 3  pleats are formed by the series of pleating rollers  302  and  306 . The pleating rollers  302  can be spaced about approximately ⅜ to ½ of an inch as indicated by arrow  301 , and the roller width between fingers, is preferably about ⅜ th  of an inch. The unpleated sheet edge is indicated by the reference numeral  340 . The upper section  314  of the pleats engages the projection of the fingers,  316  and  318  and correspondingly, the lower section  313  of the pleats engage the fingers  312  and  320 . Arrows  303  indicated the pleat height. As illustrated in  FIG. 3 , the fingers indicated by reference numerals  312  and  320  are positioned in the gap between the rollers and the shaft  322 , called the keys. The width of the narrow rollers  302  indicated by arrows  303  is about ⅜ th  of an inch, and the width of the wide rollers  332  is about 1.1 inches wide as indicated by arrow  353 . The two narrower sections  302  are about 0.375 inches in width as indicated by arrow  303  and spaced about 0.365 inches, as indicated by arrow  301 . The steel core shaft  360  is preferably about 1 inch in diameter and the pleating rollers  332  and  302  preferably have a diameter of about 1.5 inches. Advantageously, the dimensions are within 10% plus or minus of the preferred dimensions. The width of the fingers  316  is less than the space  301  between rollers in order to provide clearance between the fingers and the rollers. The width of the fingers can be about 0.25 inches.  
         [0040]     The embodiment of  FIG. 4  shows a pair of pleat roller  402  driving a sheet of paper  400  in the direction of the indicated by the arrow  406 . The backpressure is indicated by arrow  412 . It should be understood that an equivalent backpressure is applied to each pleat roller. The pleating action begins in the region upstream and proximate the projections of the fingers. The formation of the pleats  420  can be adjusted by the movement of the fingers toward or away from the pleat rollers, as indicated by arrows  404 .  
         [0041]     In the embodiment of  FIG. 5  the pleating region is indicated generally as  500 . The pleating rollers  504  and  506 , are shown with their corresponding shafts  522  and  524 . The direction of rotation is indicated by arrow  520 . The fingers  508  and  510  are adjustable as indicated by arrows  514 . The formed pleats are indicated by reference numeral  512   a.  The threaded member  518  is shown extending into the path of the pleats. The pleating action is shown to begin with the paper contacting the surface of a finger. The pleats are backed up or essentially closed due to the action of the threaded member  518  that projects into the path of the pleated paper. When the paper moves downstream of the project, the pleats can open to some extent.  
         [0042]     The mechanism for driving the rollers may be gears, belts or other know driving mechanisms. Preferably, only one pleating roller is driven and the other rollers rotate due to the pressure applied to them by other rollers.  
         [0043]      FIG. 6  illustrates the use a pleating operation in which the pleating starts prematurely. It is seen that pleating of the paper  904  begins at the exit point  960  from the pleating rollers  900  and  902 . The pleats are compacted in region  903  until they reach the adjustable project between the fingers  950  and  952 , and then can open up. In this type of sequence, the pleats may be defective and it may not be possible to obtain continuous pleating.  
         [0044]      FIG. 7  illustrates the use of a pair of pleat rollers  900  and  902  form of a material, such as a rubber having a durometer hardness of about 80, such that the contact regions of each pair of rollers can flatten. As illustrated in  FIG. 6 , the peripheral surfaces of the rollers  900  and  902  between the points  960  and  962 , can contact a plurality of pleat apices. It has been found that using rollers having a small enough diameter to minimize or negate the contacting action between the roller surface and a plurality of pleat apices, greatly increases the reliability of the pleating system, and facilitates the operation of the system at unexpectedly high out puts.  
         [0045]     While the theory of what is happening or might happen during a pleating operation is not part of the invention, a discussion of the theory is provided for the purpose of attempting to provide a full understanding of what is happening or what might be happening. It should be understood that the description of the theory of the operation does not serve to limit the scope of the invention.  
         [0046]     The pleating system as shown in  FIG. 6 , starts with fingers  950  and  952  respectively, manufacturing pleats with the pressure from rolls  900  and  902  respectively. The pleat-pack  903  is the point at which the pleats make vertical 0 degree apices. If the diameters of the pleating rollers  900  and  902  are large then the distance to the point of manufacture of the pleat-pack  903  becomes longer than the pleat height, which appears to allow the pleats to form on the rolls  900  and  902  rather than on the fingers  950  and  952 . The arc of the rollers between the point  960  at which the paper  904  leaves the pleating roller and the point  962  where the paper first contacts the inner surface of the fingers  950  and  952  should be no longer than the pleat height.  
         [0047]     As illustrated in the embodiment of  FIG. 7 , to further facilitate the desired pleating action an 80-durometer roller  900  and  902  is allowed to compress and deform substantially to a flat region, which inhibits pleating on the roll as, shown in  FIG. 6 . The flattening of the rollers is understood to facilitate the pleating operation by decreasing the arc of the roller between the point  921  at which the paper leaves the pleat rollers and the pleat point  920  at which pleating starts. The flattening of the rollers thus is sufficient to decrease the arc of the roller between the point  921  at which the paper leaves the pleat rollers and the pleat point  920  at which pleating starts.  
         [0048]      FIG. 8  is an enlarged view of the finger assembly and provides preferred dimensions. It should be noted that the Kraft paper weight can be in the range from about 30 to 55 pounds per 3,000 sq. ft. Dimension a represents the height of a finger at the end proximal to the pleat roller. Dimension “a” is preferably about 0.23 inches.  
         [0049]     Dimension “c”=0.8 inches, and represents the distance of the projection to the proximal end of the fingers. The diameter of threaded projection member  1522  is preferably about 0.15 inches. Distal end dimension “e”=0.215, and is noted to be less than the proximal end dimension. The finger length “f” is 3.5 inches and the fingers have a travel that is varied b 6  sliding carriers  1505  and  1503  on tracks not shown. A radius section  1536  to reduce paper interference is preferably 0.225 inches. This leaves a pleating area “h” of about 0.575 inches which is preferred.  FIG. 9  illustrates the projection member  1522  projecting from the lower surface of the upper finger  1510 . Dimension “b” represents the extent to which the threaded projection member  1522  projects into the path of the pleats. The preferred dimension is about 0.020 inches. This projection or bump is variable and provides backpressure to the pleats.  
         [0050]     Although the present invention has been fully described in conjunction with several embodiments thereof with reference to the accompanying drawings, it is to be understood that various changes and modifications may be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart there from.