Patent Publication Number: US-10315227-B2

Title: Stepped wall singulator conveyor for oversized item removal

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional 62/387,286 filed on Dec. 23, 2015 and is a Continuation-In-Part application of U.S. Ser. No. 15/330,185 filed on Aug. 20, 2016 which is a Continuation application of U.S. Pat. No. 9,452,449 which issued from U.S. application Ser. No. 14/544,890 filed on Mar. 3, 2015 and also claims priority from EPO Application 15759058.9 filed on Aug. 31, 2016 claiming priority from PCT/US15/000034 filed on Mar. 3, 2014 all of which are incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     This invention relates generally to a static conveyor assembly for separating and aligning parcels, packages, bags and other articles prior to processing with a singulator. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to material handling and in particular to methods and apparatuses for conveying packages and a mechanism for controlling the location of packages on a conveyor. 
     Conventional conveyor systems convey large numbers of packages at high speed, especially in the parcel delivery industry wherein the packages are sorted according to the desired categories. The efficiency with which the packages are handled can be seriously diminished when a plurality of smaller packages, irregular sized or shaped items, or a mixture of oversized, large, and small articles pass together on the conveyors as a single unit. 
     Problems occur with scanning and separating packages and parcels which travel through the conveying system as an aggregate unit rather than in a single file and with oversize packages. Large packages hide small parcels and small side-by-side packages cause problems whenever they pass simultaneously through a scanner causing confusion and sorting problems. Moreover, packages such as bags or other flexible containers having the weight distributed unevenly, or where the width and length of the container are extreme, or where the container is soft or only partially full such as a floppy partially filled bag of mail tend to present sorting problems in that they do not move in predictable lateral patterns. 
     Typical conveyor systems for sorting parcels in typical applications comprise devices that take randomly arranged items and convert the random flow to a single file stream of items. The items are conveyed forward with both forward and lateral forces and aligned along one side. An ejector, ramp or other device can be placed after the aligned stream of items in order to remove items that did not make it all the way to the side wall on the aligned side to be separated laterally away from the primary stream of parcels. Typical configurations direct the laterally removed items and recirculate them back to the skewed roller section for another pass and opportunity to be aligned against the wall, to be passed through with the primary line of flow. Items are conveyed forward with both forward and lateral forces and aligned along one side. 
     Present technology works well for rigid parcels, like a box, but items that do not behave as a rigid item like flexible parcels or large bags containing several small items and oversized parcels are separated in accordance with their center of gravity and need to be removed from the parallel stream when the item is not aligned in single file. 
     Rearrangement of clusters of articles into a singulated single file is difficult to accomplish with packages having one dimension that is significantly greater than its other dimensions. If several packages having unequal loading, partially filled bags or boxes, or long and slender articles are conveyed side-by-side, conventional article singulation conveyors have difficulty separating side-by-side pairs into single file especially over a short distance and residence time. Occasionally instead of being positioned in single file, some of the packages may be conveyed abreast of one another, i.e., in side-by-side relationship traveling two abreast. The combined width of the two packages may present a problem at a downstream location in the conveyor system especially if one or both packages are oversize. 
     The need exists for a simple means of removing oversized items such as a stepped wall singulator conveyor assembly for removal of oversized items which may be used as a module in a conveyor system or be used together with a singulator conveyor to organize packages having unequal weight, irregular dimensions, and off-set center of gravity. 
     SUMMARY OF THE INVENTION 
     This invention relates generally to a conveyor assembly for separating and aligning parcels, packages, bags and other articles prior to processing with a singulator apparatus. The stepped wall assembly includes a low friction conveying surface having both forward and lateral conveying forces for moving articles toward a lateral sidewall and a downstream conveyor. A series of offsets disposed between lateral and diverging sidewalls force parcels toward the center of the conveyor against the lateral forces of the low friction conveying surface gradually separating and converging the parcels toward a selected sidewall section of the conveyor and in line with a singulator apparatus. 
     The stepped wall singulator conveyor includes a lateral sidewall section spaced apart and generally parallel with an opposing diverging sidewall section. The conveyor rollers are positioned horizontally at a selected angle with respect to the lateral sidewall section and diverging sidewall section whereby the distal end of the conveyor rollers adjacent the lateral sidewall section extend forward a greater distance than the distal end of the conveyor rollers adjacent the opposing diverging sidewall section creating lateral forces which tend to move parcels inwardly against the diverging sidewall section. 
     A first section having a first inwardly directed offset extends at a selected angle from a first diverging sidewall section forcing articles to move against the lateral force of the conveyor and toward the center of the conveyor for a selected distance and then the sidewall section is angled inward parallel with the lateral sidewall section a selected distance. 
     A second section having a second inwardly directed offset extends at a selected angle from a first diverging sidewall section forcing articles to move against the lateral force of the conveyor and toward the center of the conveyor for a selected distance and then the sidewall section is angled inward parallel with the lateral sidewall section a selected distance. 
     A plurality of sections can be disposed between a feed conveyor and a singulator or takeoff conveyor to separate and singulate parcels along the diverging sidewall sections which converge closer to the lateral sidewall section after each offset. 
     At a selected position along the conveyor the diverging sidewall section is parallel with the opposing lateral sidewall section for a selected distance. The diverging sidewall section is angled outwardly away from the center of the conveyor at a selected angle forming a step whereby parcels are spaced apart from the diverging sidewall section prior to entering a singulator apparatus. A raised high friction conveying surface or rail belt extends along an outer edge of the low friction conveyor parallel to the lateral section of the diverging sidewall section as the lateral conveyor sidewall section terminates. At least a portion of the high friction belt is raised above the surface of the adjacent conveying surface in flow communication with the low friction conveying surface. Parcels contacting the high friction belt are prevented from shifting over toward the sidewall section and parcels having a center of gravity outside the tipover point fall over the belt onto a recirculation conveyor. 
     The present invention comprises or consists of a stepped wall singulator conveyor assembly for use with upstream and downstream conveyors for removal of oversize parcels. The stepped wall singulator conveyor assembly is insertable at selected positions within the conveying system and can be an integral unit or can include a plurality of conveyors linked together. It includes at least one low friction conveying surface having both forward and lateral conveying forces such as a plurality of driven skewed rollers having rotary axes skewed relative to a longitudinal direction of travel for moving articles toward a parallel second lateral sidewall section and a downstream conveyor. At a selected position, a first diverging sidewall section gradually converges parcels toward the center of the conveyor against the lateral motion imparted by the skewed low friction rollers. An inwardly directed offset extends from the first diverging sidewall section to the second lateral sidewall section defining an offset for shifting parcels, packages, and bags inwardly toward the second lateral sidewall section due to the forward and lateral forces of the low friction conveyor. Parcels conveyed on the outer portion of the low friction conveyor fall off of the end of the conveyor onto a take off ramp. Parcels which are biased against the first diverging sidewall section are conveyed forward and parcels which are conveyed near the center of the conveyor are moved forward and engage a high friction conveying surface such as a conveyor belt. 
     A raised high friction conveying surface, such as a rail belt, extends along an outer edge, parallel to the low friction conveyor and forward direction of travel prior to the conveyor belt. At least a portion of the high friction belt is raised above the surface of the adjacent conveying surface in flow communication with the low friction conveying surface. Oversized parcels contacting the high friction belt are prevented from shifting over toward the second lateral sidewall section so that packages having a center of gravity outside the tipover point fall over the belt onto a ramp extending from the outer edge of the rail belt and low friction conveying surface of the stepped wall singulator conveyor assembly down to a recirculation conveyor. 
     More particularly, a stepped wall singulator conveyor conveying apparatus for removing oversize parcels, comprising or consisting of a conveyor includes a low friction conveying surface for conveying parcels in a forward direction and a lateral direction. A first sidewall section extends outwardly along an inward side edge of the conveyor at a selected position for a selected length. A second sidewall section extends along an inward side edge of the conveyor at a selected position for a selected length downstream from at least a portion of the first sidewall section. An offset extending from the first sidewall section toward the second sidewall section. A high friction belt of a selected width extends along an outer edge of the conveyor opposing the second sidewall section and is raised a selected height above the surface of the low friction conveying surface and in flow communication therewith. The raised belt forms a tip-over threshold. 
     In one preferred embodiment, the high friction conveying surface has a least a portion raised above the level of the low friction conveying surface which may be adjacent to or in close proximity thereto. It is contemplated that a strip of material comprising a low friction conveyor or static surface may separate the high friction conveying surface and the low friction conveying surface which may comprise a conveying surface having a forward direction or more preferably a conveying surface having a forward and lateral direction such as driven skewed rollers having axes skewed relative to the longitudinal direction of travel for moving articles toward the second lateral sidewall section. 
     A raised high friction conveying surface, such as a belt, extends along an outer edge, parallel to the low friction conveyor and forward direction of travel. At least a portion of the high friction belt is raised above the surface of the adjacent conveying surface in flow communication with the low friction conveying surface. Oversized parcels contacting the high friction belt are prevented from shifting over toward the second lateral sidewall section packages having a center outside the tipover point fall over the belt onto a ramp extending from the outer edge of the stepped wall singulator conveyor assembly down to a recirculation conveyor. 
     The raised high friction conveying surface or belt comprises a narrow belt which extends along an outer edge, parallel to the low friction conveyor and forward direction of travel. At least a portion of the high friction belt is raised above the surface of the adjacent conveying surface in flow communication with the low friction conveying surface. Raising the narrow belt disposed at or near the edge of the conveying surface creates a tip over threshold. Of course, the adjacent supporting surface or portion of the conveyor surface may be lowered with respect to the high friction belt to create a tip over threshold as well. Oversized parcels contacting and supported by the narrow high friction belt are moved forward and prevented from shifting over toward the second lateral sidewall section. Packages having a center of gravity outside the tipover point fall off over the side of the narrow high friction belt and slide down to a recirculation conveyor or they are carried forward in a straight path where the width of the conveyor narrows so that the parcels or packages fall of the end of the conveyor onto a ramp and are removed from the conveying line. Packages which do not engage the high friction belt are conveyed downstream to a separation conveying assembly such as a singulator or side by side eliminator conveying surface. 
     A singulator conveyor can be used to remove the oversized parcels or side-by-side parcels having a surface engaging the high friction belt which resist lateral movement imparted by the skewed rollers toward the second lateral sidewall section. A singulator conveyer has separation and orientation capabilities effective in separating side-by-side packages and parcels having unequal loading such as different sized packages (e.g., boxes, flats and softpacks), partially filled bags or boxes, or long and slender articles having an offset center of gravity into one or more rows of single file singulated articles over a short distance and residence time. The parcels which are not biased against and/or aligned with the second lateral sidewall section engage the high friction belt and are carried forward onto the conveying surface of the singulator or side by side eliminator, or singulator and then the side by side eliminator where any parcels which are wider than the threshold are removed from the flow do not pass through but tip over onto a ramp and slide down to a recirculation conveyor. 
     Thus, the stepped wall singulator conveyor assembly can be combined with a downstream singulator to insure that two of more small items abreast of one another are separated while permitting large items to pass thorough the singulator even when the item is a large bag of small items. which may be used alone or in combination with singulators using a plurality of driven rollers or belts whose axes extend obliquely relative to the direction of conveyance to cause packages to be displaced laterally toward one side of the conveyor and become aligned behind one another. 
     The upstream conveyor has a greater width than each of the downstream conveyors, and the width of the side by side eliminator conveyor is less than one-half the width of the upstream conveyor. This tends to ensure that the downstream conveyor receives only packages arranged in single file and having a width less than the width of the downstream conveyor, in order to minimize the risk of jams occurring in downstream turns of the conveyor system. The singulator also includes a more narrow width that the upstream conveyor in order to remove packages which have a center of gravity extending over the outer edge. A ramp extends from the drop zone conveyor to a recirculation conveyor. A ramp may also be extended or added to the outer portion of the discharge end of the stepped wall singulator conveyor and adjacent to the outer edge of the singulator or side by side eliminator conveyor which may be positioned in a series or separated by other conveying systems. 
     It is an object of the present invention to provide a stepped wall singulator conveyor assembly having a low friction conveying surface providing forward and lateral force toward a sidewall section and a high friction belt raised above the level of the adjacent conveyor to engage parcels, and impede the lateral movement of parcels in contact with the high friction belt wherein the parcels are conveyed forward and separated by weight or size. 
     It is an object of the present invention to provide a conveyor assembly having a first diverging sidewall section which terminates in a n inwardly extending step or offset connecting to a second lateral sidewall section extending along the inner edge of the conveyor parallel thereto creating a shift region. A low friction surface including both forward and lateral conveying forces move articles inwardly toward a first diverging sidewall section and a lateral side wall. 
     It is an object of the present invention to provide a driven conveyor lane surface including rollers having a low friction surface and rotary axes skewed relative to a longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forward and laterally inwardly toward a vertical side wall where incoming items are positioned there along at a selected speed. 
     It is an object of the present invention to provide a raised high friction belt extending along the lateral outer edge of the conveyor and the upper edge of the drop zone so that packages resting on the high friction belt and conveyor having a low friction surface will be prevented from making the shift toward the sidewall section. 
     It is an object of the present invention to provide a high friction raised rail belt which runs at a selected speed greater, lower, or at the same speed as the vector speed of the rollers on the adjacent conveyor in the primary flow direction and is raised up above the roller surface up an effective distance to contact and hold packages resting on the belt and adjacent conveying surface. 
     It is an object of the present invention to provide a high friction raised belt which runs at a speed which matches the vector speed of the rollers on the adjacent conveyor in the primary flow direction and is raised up above the roller surface at an effective height for contacting and holding parcels in contact therewith. At least one preferred embodiment extends a selected height or distance of up to 5 inches, and more preferably up to 3 inches, and more preferably from ⅛ to 2 inches, more preferably from ½ to 2 inches and preferably about 1 and ½ inches to contact and hold packages resting on the belt and adjacent conveying surface. 
     It is an object of the present invention to insert the stepped wall singulator conveyor assembly into a conveyor system as a unit which may be utilized together with a singulator, side by side eliminator, or other type of conveyor unit. 
     It is an object of the present invention to provide a high friction belt which is narrow enough to have an effective width enabling raising of the belt or lowering the conveying area around the belt creates a tipover threshold for packages having a portion extending over both sides of the belt. 
     Other objects, features, and advantages of the invention will be apparent with the following detailed description taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the several views and wherein: 
         FIG. 1  is a top plan view of the stepped wall singulator conveyor for oversize item removal in combination with a singulator apparatus showing a low friction conveying surface having both forward and lateral conveying forces for moving articles toward a lateral sidewall section and a downstream conveyor and a series of offsets disposed between straight and diverging sidewall sections force parcels toward the center of the conveyor against the lateral forces of the low friction conveying surface gradually separating and converging the parcels toward a selected sidewall section of the conveyor and in line with a singulator apparatus; 
         FIG. 2  shows a perspective downstream side view of the stepped wall singulator conveyor assembly including the upstream conveyor, offset wide wall shift, conveyor with adjacent raised high friction rail belt, side by side eliminator conveyor with take off ramp and recirculation conveyor; 
         FIG. 3  shows a perspective downstream end view of the stepped wall singulator conveyor including the upstream conveyor, 9 inch offset wide wall shift, 36 inch low friction conveyor with high friction rail belt, and 12 inch side by side eliminator conveyor or singulator comprising a narrow conveyor providing a tipover threshold in flow communication with a take off ramp and recirculation conveyor wherein the articles flow from the upstream conveyor toward a 36 inch low friction convey having the high friction rail belt disposed along the outer sidewall section so that oversize items having a center wider than 36 inches will engage the high friction rail belt and will not make the shift toward the sidewall section resulting in the center of the article being more than 6 inches to the left of the tipover threshold; 
         FIG. 4  shows the stepped wall singulator conveyor assembly including packages of various sizes positioned via the offset sidewall section wherein the larger packages which engage a high friction belt which prevents them from making a shift toward the side whereby the oversized items tipover and onto a ramp; 
         FIG. 5  shows the stepped wall singulator conveyor assembly including packages, parcels, or articles of various sizes positioned via the offset sidewall section wherein the larger oversize packages which do not extend over to and engage a high friction belt are shifted via low friction skewed rollers over against the side wall and pass through a side by side eliminator so itmes below a selected threshold make the shift and the center of the item is inside of the tipover point and pass through the singulator, and oversize items above the selected threshold engage the raised high friction belt adjacent the conveyor and do not make the shift prior to the singulator and are tipped over onto a take off ramp; 
         FIG. 6  shows the stepped wall singulator conveyor oversize item removal assembly wherein packages are conveyed downstream via an upstream conveyor including an offset sidewall section, a conveyor including a high friction raised belt along the outer edge of the conveyor and a side by side eliminator conveyor transferring packages to a downstream conveyor; 
         FIG. 7  shows the stepped wall singulator conveyor oversize item removal assembly wherein packages are conveyed downstream via an upstream conveyor including an offset sidewall section, a conveyor including a high friction raised belt along the outer edge of the conveyor, a downstream singulator conveyor system, and a side by side eliminator conveyor transferring packages to a downstream conveyor; 
         FIG. 8  shows the stepped wall singulator conveyor oversize item removal assembly wherein packages are conveyed downstream via an upstream conveyor including an offset sidewall section, a conveyor including a high friction raised belt along the outer edge of the conveyor, a downstream conveyor, a singulator conveyor system, and a side by side eliminator conveyor transferring packages to a downstream conveyor; 
         FIG. 9  is a top plan view of the stepped wall singulator conveyor assembly showing a selected point opposite the first diverging sidewall section near the offset section an outward converging edge portion of the conveyor converges toward the opposing lateral wall inwardly to about 36 inches at a point where the raised belt begins and the inwardly directed offset extends from the first diverging sidewall at a selected angle; 
         FIG. 10  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel positioned along the first diverging sidewall section supported by the low friction conveyor wherein the parcel has a width below the threshold shift over for which does not contact the high friction conveyor and is conveyed through the conveyor system; 
         FIG. 11  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel positioned along the transition region between the first diverging sidewall section and second lateral sidewall section supported by the low friction conveyor wherein the parcel has a width below the threshold shift over for which does not contact the high friction conveyor and is conveyed through the conveyor system; 
         FIG. 12  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel positioned on a singulator conveyor having a ramp extending to a drop zone and onto a recirculation conveyor wherein the parcel has a width below the threshold shift over and is conveyed through the conveyor system; 
         FIG. 13  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel which has passed through the singulator conveyor and onto a side by side eliminator conveyor having a ramp extending to a drop zone and onto a recirculation conveyor wherein the parcel has a width below the threshold shift over and is conveyed through the conveyor system; 
         FIG. 14  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel which has passed through the singulator conveyor and side by side eliminator conveyor wherein the parcel has a width below the threshold shift over parameters and is conveyed through the conveyor system; 
         FIG. 15  is a top plan view showing the upstream conveyor providing input flow, forward conveying rollers having their rotary axes normal to the longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forward downstream and laterally inwardly toward a diverging sidewall to a thirty-six inch low friction conveyor with a raised high friction rail belt on an outside and an offset nine inch wide wall shift on the opposing side feeding a narrow twelve inch side by side eliminator conveyor providing a tipover threshold and a with take-off ramp whereby an article having a center less than thirty-six inches will engage the high friction belt and pass through and over the singulator making the shift toward the sidewall because the center of the article will be less than 6 inches to the left of the tipover threshold; 
         FIG. 16  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel positioned along the first diverging sidewall section supported by the low friction conveyor wherein the parcel has a width above the threshold shift over which contacts the high friction conveyor; 
         FIG. 17  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel positioned between the second lateral sidewall section supported by the low friction conveyor wherein the parcel has a width above the threshold shift-over which contacts the high friction rail belt conveyor which prevents inward lateral movement of the parcel and provides forward conveyance thereof; 
         FIG. 18  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel which has discharged from the high friction belt of the stepped wall singulator conveyor and conveyed onto a singulator conveyor having a ramp extending to a drop zone and onto a recirculation conveyor wherein the parcel has a width below the threshold shift over and will tip over onto the ramp; 
         FIG. 19  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel which has passed through the singulator conveyor which has tipped over because the parcel has a width above the threshold limit and slides down a ramp extending to a drop zone; 
         FIG. 20  is a top plan view of the stepped wall singulator conveyor assembly showing a parcel which has passed through the stepped wall singulator conveyor assembly and onto the singulator conveyor before being tipped over because the parcel has a width above the threshold limit and slides down a ramp extending to a drop zone and onto a recirculation conveyor; 
         FIG. 21  is a top plan view showing the upstream conveyor providing input flow, forward conveying rollers having their rotary axes normal to the longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forward downstream and laterally inwardly toward a diverging sidewall to a thirty-six inch low friction conveyor with a raised high friction rail belt on an outside and an offset nine inch wide wall shift on the opposing side feeding a narrow twelve inch side by side eliminator conveyor providing a tipover threshold and a with take-off ramp whereby an article having a center wider than thirty-six inches will engage the high friction belt and drop off to a recirculation conveyor instead of making the shift toward the sidewall because the center of the article will be more than 6 inches to the left of the tipover threshold; 
         FIG. 22  is a top plan view of the stepped wall singulator conveyor showing a low friction conveying surface having both forward and lateral conveying forces for moving articles toward a lateral sidewall section and a downstream conveyor and a series of offsets disposed between straight and diverging sidewall sections force parcels toward the center of the conveyor against the lateral forces of the low friction conveying surface gradually separating and converging the parcels toward a selected sidewall section of the conveyor and in line with a singulator apparatus; 
         FIG. 23  is a top view of the stepped wall singulator conveyor of  FIG. 22  showing the angle the conveyor rollers are offset from the lateral sidewall section, the angle of the diverging sidewall section with respect to the conveyor rollers and the angle of the diverging sidewall sections; and 
         FIG. 24  is a perspective view of the stepped wall singulator conveyor assembly for separating and organizing parcels showing sections including a lateral sidewall section with diverging sidewall sections including offsets extending there between at selected positions, the low friction conveying surface with driven skewed rollers exerting forward downstream force and lateral force inwardly toward the second lateral sidewall section, the high friction raised belt extending along the outer edge of the portion of the conveyor downstream from the offset, a side by side eliminator conveyor downstream from the stepped wall singulator conveyor assembly with a discharge ramp extending from the side in flow communication with parcels from the side by side eliminator and discharge portion of the stepped wall singulator conveyor extending outwardly past the outer edge of the side by side eliminator. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As used herein, the term “about” can be reasonably appreciated by a person skilled in the art to denote somewhat above or somewhat below the stated numerical value, to within a range of ±10%. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “above,” “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. When the claims use the word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list 
     As shown in  FIGS. 1-24 , the present invention comprises or consists of a stepped wall singulator conveyor assembly  10  for use with upstream and downstream conveyors for removal of oversize parcels. The stepped wall singulator conveyor assembly  10  is insertable at selected positions within the conveying system and can be an integral unit or the unit can include a plurality of conveyors linked together. 
     At a selected position along the conveyor the diverging sidewall section is parallel with the opposing lateral sidewall section for a selected distance. The diverging sidewall section is angled outwardly away from the center of the conveyor at a selected angle forming a step whereby parcels are spaced apart from the diverging sidewall section prior to entering a singulator apparatus. A raised high friction conveying surface or rail belt extends along an outer edge of the low friction conveyor parallel to the lateral section of the diverging sidewall section as the lateral conveyor sidewall section terminates. At least a portion of the high friction rail belt is raised above the surface of the adjacent conveying surface in flow communication with the low friction conveying surface. Parcels contacting the high friction rail belt are prevented from shifting over toward the sidewall section and parcels having a center of gravity outside the tipover point fall over the rail belt onto a recirculation conveyor. 
     As shown in  FIGS. 1-24 , and more particularly in  FIGS. 22-24 , the stepped wall singulator conveyor assembly or module  10  is comprised or consisss of an integral unit whereby the conveyor surface is continuous and comprise or consist a series of driven rollers  11 . Conveyors upstream or downstream of the stepped wall singulator conveyor assembly  10  comprises or consists endless conveying rollers  12  having their rotary axes normal to the longitudinal direction of travel. At least a selected portion or sections of the stepped wall singulator conveyor  10  adjacent a divergent sidewall section  28  and downstream second lateral sidewall section  40  are skewed relative to a longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forward L downstream and laterally inwardly L′ toward a first diverging sidewall section  28 . The skewed rollers  15  comprise or consist a series of driven rollers having rotary axes skewed relative to a longitudinal direction of travel so that the packages are conveyed simultaneously longitudinally forward and laterally outwardly. 
     The high friction conveyor(s) comprise or consist conveying surfaces of solid or mesh belts comprising rubber, elastomers, polymers, and combinations thereof providing a high friction material as compared with the low friction conveying surface. The high friction conveying surface may also comprise or consist rollers having at least a portion thereof covered or coated with a high friction surface such as a rubber, plastic, elastomer or other polymeric material including sleeves or bands composed of same. The low friction conveyor, conveying surface or conveying lane comprises or consists of a lower friction material such as metal including aluminum, stainless steel, steel, TEFLON, NYLON, graphite, or other polymeric material including sleeves or bands composed of same which comprises or consists of a low friction material when compared to the high friction conveying surface. The low friction convey surface may be formed by using a plastic modular belting, containing driven rollers, a belt, or a belt and/or rollers coated with a low friction coating. 
     As shown best in  FIGS. 1 and 22-24 , articles are fed onto the conveyor upstream of the stepped wall assembly  100  having a inner sidewall section  7  which is parallel to an opposing lateral sidewall section  23 . The stepped wall assembly  100  includes a low friction conveying surface  15  having both forward and lateral conveying forces for moving articles toward a diverging sidewall section  7  and a downstream conveyor. A series of offsets disposed between lateral and diverging sidewall sections force parcels toward the center of the conveyor against the lateral forces of the low friction conveying surface gradually separating and converging the parcels toward a selected sidewall section of the conveyor and in line with a singulator apparatus. 
     The stepped wall singulator conveyor includes a lateral sidewall section spaced apart and generally parallel with an opposing diverging sidewall section. The conveyor rollers are positioned horizontally at a selected angle of up to 40 degrees, more preferably from 10 to 30 degrees, and more preferably about 22 degrees with respect to the lateral sidewall section and diverging sidewall section whereby the distal end of the conveyor rollers adjacent the lateral sidewall section extend forward a greater distance than the distal end of the conveyor rollers adjacent the opposing diverging sidewall section creating lateral forces which tend to move parcels inwardly against the diverging sidewall section. 
     A first section having a first inwardly directed offset  21  extends at a selected angle of to 45 degrees, more preferably from 10 to 30 degrees, and more preferably about 22 degrees from a first diverging sidewall section forcing articles to move against the lateral force of the conveyor and toward the center of the conveyor for a selected distance. The diverging sidewall section  7  is angled inward forming a section  20  parallel with the lateral sidewall section  23  a selected distance along the conveyor. 
     A second section of having a second inwardly directed offset  22  extends at a selected angle from diverging sidewall section  20  forcing articles to move against the lateral force of the conveyor and toward the center of the conveyor for a selected distance and then the sidewall is angled inward forming parallel section  28  parallel with the lateral sidewall  23  a selected distance. 
     A plurality of sections can be disposed between a feed conveyor and a singulator or takeoff conveyor to separate and singulate parcels along the diverging sidewalls which converge closer to the lateral sidewall after each offset. 
     At a selected position, a first diverging sidewall section  28  gradually extends outwardly from a second lateral sidewall  40  extending along the inward edge of the conveying surface. The diverging sidewall diverts, aligns, and forces the parcels toward the center of the conveyor against the lateral and forward motion imparted by the skewed low friction rollers. The lateral forces imposed by the skewed rollers  15  of the low friction conveying surface  17  force the parcels against the first diverging sidewall which separates, aligns, and biases the parcels and packages on the low friction conveyor against the first diverging sidewall. An inwardly directed offset  42  extends from the first diverging sidewall section  28  at a selected angle to the second lateral sidewall  40  to narrow the width of the conveying surface, shift parcels, packages, and bags moving forward against the first diverging sidewall section  28  inwardly toward the second lateral sidewall  40  due to the forward and lateral forces of the low friction conveyor. The first diverging sidewall section  28  also diverts or conveys large oversize parcels toward the center of the conveyor which is about 36 inches, (36″), wide at the point of the offset section  42  where the diverging sidewall section  42  connects to the second lateral sidewall section  40  opposite the front end of the raised rail belt  50 . In one preferred embodiment, the first diverging sidewall section  28  is offset approximately 9 inches inwardly from the second lateral sidewall section  40 . It is contemplated that the first diverging sidewall section  28  can overlap or start in close proximity to the distal end of the second lateral sidewall section  40  or be an extension thereof. 
     As shown in Figures, at a selected point opposite the first diverging sidewall section  28  near the offset section  42 , an outward converging edge portion  24  of the stepped wall singulator conveyor  10  converges toward opposing lateral wall  23  inwardly toward the preselected width of about 36 inches at conveyor section  17 , or prior to, the termination of the first diverging sidewall section  28  forming a throat for converging and aligning packages near the center of the conveyor  10 . 
     Parcels biased against the first diverging sidewall section  40  are conveyed forward. Parcels conveyed near the center of the conveyor are moved forward and engage a high friction conveying surface such as a raised rail belt  50  disposed along the outer edge of the conveying surface. The high friction conveying surface has at least a portion thereof raised above the level of the low friction conveying surface and is in flow communication therewith so that parcels resting on the high friction conveying surface have at least a portion thereof resting on the low friction conveying surface. Preferably the low friction conveying surface comprises or consists of a conveying surface having a forward direction and/or a conveying surface having a forward and lateral direction such as driven skewed rollers having axes skewed relative to the longitudinal direction of travel for moving articles toward the second lateral sidewall and away from the high friction conveying surface. 
     In at least one preferred embodiment, the high friction conveying surface comprises or consists a narrow high friction raised rail belt  50 , such as a V belt having an effective width for holding packages or parcels which are conveyed onto the rail belt to hold the parcels resting on the rail belt and low friction conveying surface forward preventing lateral movement toward the second lateral sidewall  40 . The rail belt may have a convex or flat surface and have an effective width up to several inches wide so long as the outer surface of the rail belt is of a shaped providing a tip over point for parcels resting thereon. The rail belt  50  extends along the horizontal outer leading edge of the stepped wall singulator conveyor  10  for preventing oversized items resting on or engaging the rail belt from making the shaft over inwardly to the lateral side wall  40 . In one preferred embodiment, the rail belt runs at a speed which matches the vector speed of the rollers in the primary flow direction. The rail belt  50  is raised up above the low friction conveyor surface “roller surface” about 1½ inches. it is contemplated that the effective height of the rail belt above the low friction conveying surface can be from 0.1 of to 3 inches in height and more preferably about 0.5 to 2 inches above the roller surface and more preferably 1 to 1.5 inches above the roller conveying surface. While not critical, in a preferred embodiment the rail belt  50  runs at a speed which matches vector speed of the rollers in the primary flow direction and is raised up above the roller surface a selected distance of about land ½ inches. 
     The high friction rail belt  50  disposed adjacent and slightly above the outer edge  24  of the conveyor  10  prevents oversized items engaging the high friction rail belt  50  from shifting over toward the second lateral sidewall  40  and accelerates the discharge of the packages resting partially on the low friction roller conveying surface  11  and partially on the rail belt  50  having a center outside the tip-over point. The items below the threshold which do not contact the high friction rail belt  50  may shift over toward the second lateral sidewall  40  and are inside of the tipover point and therefore pass over the conveyor  10 . 
     The stepped wall singulator conveyor assembly  10  embodiment illustrated in the drawings comprises or consists of a low friction conveying surface including a plurality of skewed rollers which impart forward and lateral forces inwardly toward the first diverging sidewall  28  and the downstream second lateral sidewall section  40 . However, it is contemplated that portions of the conveyor  10  may include a low friction conveying surface comprising sections of forward conveying rollers so long as an effective amount of low friction conveying surface is available to provide a forward and lateral force toward the sidewalls prior to and opposite the rail belt. It is also contemplated that a strip of static material could be disposed between the rail belt and low friction conveying surface and/or sidewall sections  28 ,  40 , and that the oversized parcels would still be removed so long as a portion of the parcel rested upon the rail belt and a low friction surface allowing forward movement of the parcel by the rail belt. 
     As shown in  FIG. 4 , packages of various sizes are positioned via the offset sidewall wherein the larger packages engage a high friction rail belt  50  which prevents them from making a shift toward the side whereby the oversized items tipover and onto a ramp; 
     As shown in  FIG. 5 , an oversized article is positioned via the offset sidewall section wherein the package does not extend over to touch and engage the raised high friction rail belt  50  but is biased and conveyed via low friction skewed rollers  15  over against the first diverging side wall  28  past the first tipover point contacting the set off  42  and moving via the low friction skewed conveyors  15  toward the second lateral side wall  40  onto a side by side eliminator  38  or singulator  111  past the second tip off point and the drop off zone conveyor or discharge chute  44  onto a return or recirculating conveyor  45 . Both the side by side eliminator  38  and singulator include low friction conveying means such as skewed rollers disposed between a pair of high friction conveying means such as belts. 
     As shown in  FIGS. 9-21 , the high friction conveying belts of the singulator are a selected width depending upon the size of the packages and friction imparted by the surface of the selected high friction material and can be of any selected width. Items with evenly distributed weight that engage the high friction rail belt at the 36 inch threshold will fall off. The width of the singulator belts shown in the instant drawings and are typically between 3-12 inches in width and more preferably about six inches each for a conveying system and package width proportioned for the conveyor example described herein. The tip over threshold of packages having a center of gravity along the path of the outside high friction singulator conveyor is typically about the center of the conveyor section  19  between the raised belt  50  and second lateral sidewall  40 . The skewed rollers of the side by side eliminator  38  and singulator  111  bias articles away from the first diverging sidewall section  40 . The items below the threshold make the shift and the center of the item is well inside of the tipover point and therefor pass over the side by side eliminator device or singulator  38 . Thus, the oversized items which do not engage the high friction belt  50  are conveyed over a singulator, side by side eliminator device, or combination thereof align and separate the parcels whereby side by side parcels or parcels larger than a selected width drop off of the side of the conveyor onto a ramp  44  for recirculation. Since the downstream portion  36  of the stepped wall singulator conveyor  10  as shown in the figures is 36 inches in width, any packages having a center wider than 36 inches will engage the high friction belt  50  and not make the shift over to the side wall  40 . The nine inch shift due to the offset will result in the center of the package being more than six inches to the left of the tipover threshold and the package or parcel will tipover and fall onto a ramp leading to a recirculation conveyor  46 . Thus, individual oversized items that are passing that are wider than the 36 inch width will engage the high friction rail belt and not shift towards the side wall are will be removed from the flow. 
     Oversize items or packages conveyed via the stepped wall singulator conveyor assembly that has evenly distributed weight that engages the high friction rail belt at the 36 inch threshold will tipover and fall off onto the recirculation conveyor, while packages having a width of less than 36 inches pass through to the side by side eliminator conveyor  38  or singulator  111 . As shown in the figures, the conveyor assembly includes a singulator  111  positioned upstream from a side by side eliminator  38 . It is also contemplated that driven conveyors utilizing belts and/or forward motion and/or skewed rollers and combinations thereof maybe disposed between the singulator conveyor assembly or the side by side eliminator  38  device as illustrated in the figures which includes downstream conveyor  60 . 
       FIGS. 9-21  illustrate sequentially how a package moves through the stepped wall singulator conveyor assembly. The parcel is positioned along the first diverging sidewall section supported by the low friction conveyor wherein the parcel has a width below the threshold shift over for which does not contact the high friction conveyor and is conveyed through the conveyor system. The parcel moves along the transition region between the first diverging sidewall section and second lateral sidewall section supported by the low friction conveyor wherein the parcel has a width below the threshold shift over for which does not contact the high friction conveyor and is conveyed through the conveyor system. The parcel moves through a singulator conveyor having a ramp extending to a drop zone and onto a recirculation conveyor wherein the parcel has a width below the threshold shift over and is conveyed through the conveyor system. After the parcel has passed through the singulator conveyor, it moves onto a side by side eliminator conveyor having a ramp extending to a drop zone and onto a recirculation conveyor. Because the parcel has a width below the threshold shift over it is conveyed through the conveyor system. 
       FIGS. 16-21  illustrate sequentially how a package is selectively discharged through the stepped wall singulator conveyor assembly. The parcel moves along the lateral sidewall section toward the offset and diverging sidewall section supported by the low friction conveyor. The parcel has a width above the threshold shift over which contacts the high friction rail belt which prevents inward lateral movement of the parcel and provides forward conveyance thereof. The parcel is discharged from the high friction rail belt and low friction roller conveyor onto a singulator or side by side conveyor having a ramp extending to a drop zone and onto a recirculation conveyor. The parcel has a width below the threshold shift-over and will tip over onto the ramp because the parcel has a width above the threshold limit and slides down a ramp extending to a drop zone and onto a recirculation conveyor. 
     As described heretofore, the stepped wall singulator conveyor assembly combines a conveyor having a low friction conveying surface with lateral and forward conveying surfaces forcing parcels inwardly toward a first diverging sidewall section connecting to a second lateral sidewall section  40  by an offset, and a narrow raised high friction rail belt extending along the outer edge of the conveyor. 
     Oversize parcels conveyed along the outer portion of the low friction conveyor engaging the high friction belt will fall off of the end of the conveyor onto a take off ramp. Parcels which do not touch the belt and are positioned inwardly thereof are biased toward the second lateral sidewall section  40  and are conveyed downstream. 
     In one preferred embodiment, the packages moving pass the stepped wall singulator conveyor assembly  10 , move along the second lateral sidewall section  40  of the conveyor and feed the side by side eliminator conveyor  38  which is typically less than half of the width of the 36 inch wide conveyor, usually from 18-21 inches in width and preferably 12 inches wide a shown in  FIG. 3 . The side by side eliminator conveyor may include a low friction surface comprising a belt or a series of driven rollers  11  whose rotary axes normal to the direction of flow or they may be driven skewed rollers  15  relative to a longitudinal direction of travel. If the rollers are skewed the packages are conveyed simultaneously longitudinally forward and laterally inward toward a third side wall. 
     A drop off zone or ramp  44  is situated adjacent the outer edge of the side by side eliminator conveyor  38  surface for receiving packages which fall therefrom and convey the packages to a recirculation conveyor  56 . 
     Use of the side by side eliminator or singulator with the present invention provides upstream, and downstream conveying surfaces which are arranged in alignment for sequentially conveying packages. U.S. Pat. No. 5,222,586 which is incorporated by reference herein, describes a device wherein each of the conveying surfaces has a width measured from a reference line to an outer edge of the respective conveying surface. The width of the conveying surface is less than the width of the upstream conveying surface. The width of the downstream conveying surface is less than the width of the upstream conveying surface and greater than two times the width of the conveying surface. The packages are conveyed sequentially along the upstream, and downstream conveying surfaces, with inner edges of the packages traveling along the reference line. Packages traveling abreast, and packages having a width greater than the downstream conveying surface, tend to fall from the outer edge of the conveying surface. 
     The width of the upstream conveyor is greater than the width of the stepped wall singulator conveyor  10  and the downstream side by side eliminator conveyor width which is typically less than one-half of the upstream conveyor width so that the downstream conveying surface tends to receive only packages which are arranged in single file and which are of a width less that the conveyor width. 
     A single package may be of such a large width that it might jam in the downstream turns. Side by side packages or the excessively wide package that might jam downstream conveyance are removed where the width of the upstream conveyor is larger than each of the widths of the downstream and conveyors, and wherein the width of the second conveyor is less than one-half of the width of the upstream conveyor. 
     For example, if two packages traveling abreast, the outer package farthest from the side wall will have its center of gravity situated outside of the outer edge of the conveyor and will fall off that conveyor into a ramp in the drop-off zone. The ramp is situated in the drop-off zone to guide the package when it falls off the conveyor. The discharged package can then be recirculated onto the conveyor system. Alternatively, the packages can fall onto another conveyor which can transport the packages to a suitable location. The exceptionally wide package having a width greater than the width of the downstream conveyor, will have a center of gravity situated outside of the edge of the conveyor. In such case, the package will fall down the ramp. 
     It may also occur that the exceptionally wide package may have the weight of its contents distributed unevenly, such that the center of gravity of the package is disposed inwardly of the outer edge of the conveyor. That package would not ordinarily drop off of the edge; however, the high friction belt  50  adjacent the outward edge of the conveyor will hold the package preventing the package from shifting back to the side wall. The package will drop off of the conveyor onto the drop zone for recirculation. 
     In another preferred embodiment, the side by side conveyor  38  may comprise or consist of a singulator conveyor system or assembly  111  which may be inserted in place of or prior to a side-by-side eliminator  38 . As shown in the figures, a singulator assembly  111  includes first conveyor  113  including rollers or preferably a generally flat belt having a high friction surface for conveying articles along a vertical side wall  112  where incoming items are positioned therealong, a second low friction conveyor  104  which may use skewed drive rollers  115 , and a third high friction belt conveyor  105 . Packages resting against the vertical side-wall  112  and resting on the first conveyor  113  will proceed across the conveyor to the down stream conveyor which may comprise or consist of a drop off zone conveyor which is from 18-21 inches in width and typically less than half of the width of the 36 inch wide conveyor. The support surface of the drop off zone conveyor may include a low friction surface comprising a series of driven rollers  14  whose rotary axes normal to the direction of flow or they may be driven skewed rollers  15  relative to a longitudinal direction of travel. If the rollers are skewed the packages are conveyed simultaneously longitudinally forward and laterally inward toward the side wall. 
     More particularly, a typical singulator conveyor such as described in U.S. Pat. No. 5,701,989 incorporated by reference herein, describes a singulator which includes or at least two and preferably three parallel conveyors or conveying surfaces in flow communication with one another and usually adjacent one another. It is contemplated that static or stationary conveying surfaces comprise or consist strips disposed between the conveying surfaces. Applicant&#39;s U.S. application Ser. No. 14/392,374 filed on Feb. 23, 2016 claiming priority from PCT/US14/00200 filed on Jun. 23, 2016, (publication on Jul. 2, 2015 as WO 2015/060885 all of which are incorporated by reference herein, also describe a singulator comprising three parallel adjacent conveyors, the first conveyor includes a low friction surface traveling in a forward direction and lateral direction away from the first conveyor and toward the third conveyor. The edge of the second conveyor is disposed below the first conveyor and forms an inclined plane angled upward from the first conveyor toward the third conveyor but slightly above the plane of the third conveyor. In this manner, when a package travels along having a portion resting on the first and second conveyor, the package will tend to be pulled forward. Packages will tend to move from the second conveyor toward the third conveyor along the inclined plane. Moreover, packages resting on the second conveyor and third conveyor will be dragged onto the third high friction conveyor to a position where the center of gravity is over the third conveyor and supported thereon. It is contemplated that the speed of the first conveyor having a high friction surface may be increased with respect to the second conveyor which will tend to arrange packages in a single file because the package adjacent the side wall will move ahead of the package resting on the second conveyor or (first and second conveyor) as both are urged in the direction of travel. Because this feature of the invention provides for positioning and aligning packages based upon contact with any portion of the package or article, the singulator removes side-by-side packages which have a package dimension which may be transverse to the direction of travel of the conveying surface by operating on the transverse width of the package as well as the center of gravity of the package. Even when the load is not distributed uniformly such as a partially filled bag, the bag will be moved and positioned onto the first or second conveyor depending upon the center of gravity of the package. Packages resting on both the second and third conveyors having a lateral dimension transverse to the direction of travel of the conveying surface will be pulled onto the third conveyor. 
     It is also contemplated that a discharge accelerator may be provided to assist in removal of the packages from the stepped wall singulator conveyor  10 , side by side eliminator  38 , and/or singulator  111 ; however, it is typically not necessary. The discharge accelerator comprises or consists of a roller which is driven in a direction tending to frictionally displace a falling package downwardly. The roller is rotated about an axis extending parallel to the reference line defined by the wall by means of a motor. In order to ensure that the packages do not engage the roller unless they are actually falling from the conveyor, the roller is disposed at a lower elevation than the conveying surface of the conveyor. In lieu of a roller, the discharge accelerator could comprise or consists of other types of driven devices, such as a belt conveyor for example. 
     Method of Use: 
     The method for separating and removing oversized parcels with the stepped wall singulator conveyor comprises of consist essentially of the steps of conveying parcels on a low friction conveying surface in a forward direction and a lateral direction toward a first sidewall section and aligning the parcels. The parcels contact the first sidewall section and the first sidewall section diverts the parcels inwardly toward a center portion of the conveyor a selected distance against the forward direction and the lateral direction of the low friction conveying surface establishing a threshold for separation of the parcels. The parcels are conveyed on the low friction conveying surface in a forward direction and a lateral direction downstream toward a second sidewall section offset outwardly with respect to a center of the conveyor and inwardly with respect to the first sidewall section shifting the parcels having a width below the threshold against the second sidewall section for conveying downstream. The parcels having a width above the threshold are conveyed onto a raised high friction conveying surface in flow communication therewith having a tip-over threshold and extending along a side edge of the conveyor at a position generally opposite the second sidewall section and spaced apart therefrom a selected distance. The parcels having a width above the threshold and having at least a portion thereof resting on the high friction conveying surface are held away from the second sidewall section and conveying the parcels downstream. The parcels remaining on the raised high friction conveying surface are removed from the primary downstream flow adjacent the second sidewall section. 
     Parcels engaging the raised high friction conveying surface onto a side ramp are tipped over and discharged from the side of the conveyor or discharged from an outward distal end portion of the conveyor. The process may also include the step of conveying parcels having a width below the threshold and passing through the threshold onto a side by side eliminator conveyor in flow communication with the low friction conveying surface thereof. Alternatively, the step of removing oversize parcels having a width below the threshold and pass through the threshold onto a singulator conveyor in flow communication with the low friction conveying surface thereof. The process may also include the step of conveying parcels having a width below the threshold and passing through the threshold onto singulator conveyor in flow communication with the low friction conveying surface and conveying the parcels passing through the singulator conveyor to a side by side eliminator conveyor in flow communication therewith. 
     Parcels above a threshold limit of the side by side eliminator are removed by tipping the parcels over onto a ramp extending from an outer edge of the side by side eliminator conveyor, and/or singulator. 
     The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modification will become obvious to those skilled in the art upon reading this disclosure and may be made upon departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not intended to be limited by the specific exemplifications presented herein above.