APPARATUS AND METHODS FOR SINGULATING

BACKGROUND

The invention relates generally to power-driven conveyors and, more particularly, to singulators using conveyor belts with article-supporting rollers that rotate as the belts advance.

Singulating conveyors transport articles in single file. Frequently, they include a recirculating conveyor that redirects articles not in single file (referred to as "side -by-sides") back to the infeed to the singulator. In this way, the recirculation conveyor also serves as a buffer to accommodate intermittent oversupplies of articles. An elimination component strips all side-by-sides from their positions alongside the articles in the single file and feeds them to the recirculating conveyor. Typically, the recirculating conveyor is fed the side-by-sides from a gravity-roller chute or powered rollers. Consequently, some of the conveying surfaces, which are commonly formed by roller conveyors, are at different elevations. Thus, there is a need for a recirculating singulator all of whose components operate at a common vertical elevation.

SUMMARY

That need, as well as other needs, may be satisfied by a singulating conveyor system embodying features of the invention including an infeed conveyor, an elimination conveyor, and a recirculation conveyor. The elimination conveyor includes a pass-through conveyor belt portion that advances from an upstream end to a downstream end in a pass-through conveying direction. The pass-through portion extends inward from a first side of the elimination conveyor. Articles received from the infeed conveyor onto the pass-through portion pass along the elimination conveyor and off its downstream end. A second conveyor belt portion of the elimination conveyor extends inward from an opposite second side of the elimination conveyor. The second portion advances from the upstream to the downstream end of the elimination conveyor. Rotatable article-supporting rollers are arranged in the second conveyor belt portion to direct articles supported atop the rollers off the second side of the elimination conveyor. The recirculation conveyor receives the articles from the second conveyor belt portion and transports them along a recirculation conveying path back onto the infeed conveyor.

In another aspect of the invention, an elimination conveyor embodying features of the invention comprises a pass-through conveyor belt portion and a second conveyor belt portion, both advancing from an upstream end to a downstream end in a pass-through conveying direction. The pass-through portion extends inward from a first side of the elimination conveyor and passes articles it receives from an infeed conveyor off the downstream end of the elimination conveyor. The second conveyor belt portion extends inward from an opposite second side of the elimination conveyor toward the first side. Rotatable article-supporting rollers in the second conveyor belt portion are arranged to direct articles supported atop the rollers off the second side of the elimination conveyor. In yet another aspect of the invention, a method for singulating conveyed articles comprises: (a) conveying articles in a single file along one side of a conveyor providing a conveying surface advancing downstream; and (b) rotating article-supporting rollers that are disposed in the conveyor laterally offset from the single file as the conveying surface advances downstream and that are oriented to push articles atop them and side -by-side with articles in the single file away from the single file and off an opposite side of the conveyor.

BRIEF DESCRIPTION OF THE DRAWINGS

These features and aspects of the invention, as well as its advantages, are better understood by referring to the following description, appended claims, and accompanying drawings, in which:

FIG. 1 is a top plan of a singulating conveyor with a recirculating conveyor embodying features of the invention;

FIG. 2 is a top plan, partly cut away, of the elimination conveyor of FIG. 1;

FIG. 3 is a cross section of a portion of the elimination conveyor of FIG. 2 taken along lines 3-3;

FIG. 4 is a top plan, partly cut away, of another version of an elimination conveyor with transverse rollers usable in a singulator as in FIG. 1;

FIG. 5 is a top plan of another version of an elimination conveyor with transverse rollers and a widening pass-through portion usable in a conveyor singulator as in FIG. 1; FIG. 6 is a top plan of yet another version of an elimination conveyor with a frictional pass-through conveying surface usable in a singulator as in FIG. 1;

FIG. 7 is a side elevation of the elimination conveyor of FIG. 6 illustrating a vacuum hold-down system;

FIG. 8 is a top plan schematic of another version of singulating conveyor with a recirculating conveyor embodying features of the invention;

FIG. 9 is a top plan schematic of yet another version of a singulator with a parallel path for eliminating side-by-sides; FIG. 10 is a top plan schematic of the singulator of FIG. 9, but having an adjustable aligning side wall in an infeed portion of the singulator; and

FIG. 11 is a top plan schematic of a portion of a singulator as in FIG. 9, but having adjustable roller-bearing-surface zones in the elimination conveyor.

DETAILED DESCRIPTION

A singulating conveyor system embodying features of the invention is depicted in FIG. 1. Articles A and B are transported along an infeed conveyor 10 advancing in a main conveying direction 12. The infeed conveyor may be a roller conveyor, a flat belt conveyor, or a modular chain conveyor. In a preferred version, the infeed conveyor is realized as a modular plastic conveyor belt with article-supporting rollers 14 oriented to rotate in a direction oblique to the main conveying direction to push articles toward and against a side rail 16 along one side of the infeed conveyor. Bearing surfaces underlying the conveying surface of the infeed conveyor belt contact the peripheries of the rollers, which extend through the thickness of the belt. As the belt is driven forward by sprockets on a shaft 20 driven by a motor 22, the rollers roll on the underlying bearing surfaces and rotate in the direction of arrow 18.

Articles delivered onto the infeed conveyor are often crowded together along the length and width of the conveyor. Because many processing stations are designed to handle articles serially, it is often necessary to convert the mass of articles into a single file. An elimination conveyor 24 strips unregistered side -by-side articles B, side -by-sides, from pass- through articles A registered against the side rail 16 in a single file. The elimination conveyor, which is laterally offset from the side rail, receives the articles from the infeed conveyor at an upstream end 26 of the elimination conveyor. The elimination conveyor includes a conveying surface 28 formed by a conveyor belt 29 advancing from the upstream end to an opposite downstream end 27 in a pass-through conveying direction 30. The conveying surface of the elimination conveyor is divided into a pass-through conveyor belt portion 32 extending inward from a first side 34 of the belt at the side rail and a second conveyor belt portion 36 extending inward from an opposite second side 35 of the belt toward

the first side. A hashed line 38 roughly indicates the demarcation between the two portions of the conveying surface.

In this example, the pass-through portion of the elimination conveyor is formed by a portion of the conveyor belt having rollers 40 extending through the thickness of the belt. As the belt advances, the rollers, which are oriented oblique to the pass-through conveying direction, roll on an underlying bearing surface to apply a force to articles, such as article A, in the direction of arrow 41. The force maintains the articles against the side rail and away from the second conveyor belt portion 36. This allows the registered articles A to pass through the elimination conveyor in a single file and off its downstream end. The second conveyor portion is formed on the same conveyor belt 29 as the pass-through portion. Rollers 42 on the second portion extend through the thickness of the belt and roll on underlying bearing surfaces just as for the pass-through portion. The difference is that the rollers on the second portion are oriented to rotate in the direction 43 to push side-by-sides, such as article B, away from the pass-through portion and toward the second side 35 of the elimination conveyor. Preferably, the axes 44, 45 of the oblique rollers are between about 30° and 60° measured from the pass-through conveying direction. This means that the angle α between the roller axes will range from about 60° to about 120°.

The width of the pass-through portion is preferably preselected to be about the same as the width of the articles received from the infeed conveyor. In that way, side-by-sides B will rest largely on the second conveyor belt portion and be directed away from the single file of pass-through articles A. As indicated by parallel broken lines 46, 47, which represent abutting sides of abutting conveyor belts, the single conveyor belt 29 may be replaced by a pair of conveyor belts, each forming one of the two portions.

The elimination portion 36 of the elimination conveyor directs side-by- sides B off the second side 35 and onto a recirculation conveyor 48, which forms a recirculation path that guides the eliminated articles B back onto the infeed conveyor 10. In this way, the elimination conveyor, in conjunction with the recirculation conveyor, serves as a buffer to handle intermittent oversupplies of articles. The recirculation conveyor shown in this example includes an oblique-roller belt 50 whose rollers 52 are arranged to rotate in the direction of arrow 54 as the belt advances in the recirculation direction 56 along the first part of a recirculation path 57. The oblique-roller conveyor belt pulls stripped articles B from the elimination conveyor, reverses their direction of travel, registers them against the side rail 58, and delivers them to a main recirculation conveyor 60 that transports the stripped articles to

be delivered back onto the infeed conveyor. A side-feed conveyor 62 at the end of the main recirculation conveyor feeds the stripped articles back onto the infeed conveyor 10 completing the recirculation path. The rotating rollers in the elimination portion of the elimination conveyor allow the recirculation conveyor to be positioned at the same vertical level as the infeed and elimination conveyors.

Further details of the bearing surfaces underlying the belt rollers 40, 42 in the elimination conveyor belt 29 are shown in FIGS. 2 and 3. The rollers on each portion of the belt are oriented, in this example, to exert a force on conveyed articles in directions 41, 43 that are about 60° from the pass-through conveying direction 30. To enable the rollers to roll without too much slip, the bearing surfaces are formed by the peripheries of actuating rollers 64 arranged parallel to the pass-through conveying direction under the longitudinal lanes of rollers in the belt. (For smaller oblique angles for which slip is not so great a problem, flat stationery bearing surfaces, such as linear wear strips, may be used.) The actuating rollers are rotationally fixed at each end. As the belt advances, the belt rollers cause the actuating rollers to rotate and travel a helical path along their peripheries. Thus, the belt rollers engage the actuating rollers in rolling, rather than sliding, contact. Close to the line of demarcation 38 between the pass-through portion 32 and the elimination portion 36, one or more longitudinal lanes of rollers 65 may be left free to rotate without engaging an underlying actuating roller. In this case, a gap 66 is formed between the actuating rollers underlying the pass-through conveyor belt portion and the elimination portion. As best shown in FIG. 3, the pass-through belt rollers may include a peripheral tread 68 made of a high- friction rubber or elastomeric material for better frictional engagement with the bottoms of articles positioned to pass through the singulator. The belt rollers 42 in the elimination portion may have peripheries with a lower coefficient of friction, but, at oblique roller angles of 60°, a high- friction periphery makes for better engagement between the belt rollers and the actuating rollers.

In some instances, it may be desirable to disable the recirculation loop to flush articles from it. This can be done by disengaging the bearing surfaces from the belt rollers. The actuating rollers 64 in FIG. 3 are mounted in a framework to form roller arrays 70, 71 that can be selectively moved, such as raised and lowered, into and out of contact with the rollers by means of a pneumatic, hydraulic, or electromechanical actuator indicated by arrow 72. When the roller array 70 is lowered, the belt rollers 42 in the elimination portion do not rotate, and the side-by-sides atop them are allowed to pass through and off the downstream end of the elimination conveyor, bypassing the recirculation path.

Another version of the elimination conveyor embodying features of the invention is shown in FIG. 4. In this version, a conveyor belt 74 advancing in the pass-through conveying direction 30 has rows and lanes of long transverse rollers 76 with axes 78 parallel to the pass- through conveying direction. Two sets of actuating rollers 80, 81 underlie the belt. The actuating rollers 80 on one side define the pass-through portion 32 of the elimination conveyor, and the actuating rollers 81 on the other side define the elimination portion 36. The actuating rollers in each set are free to rotate on their axles 82, which are rotatably retained in a frame 84. A gap 66 between the two sets of actuating roller frames allows some of the transverse belt rollers to be fully freely rotatable in the direction of arrows 86, 87 only by contact with conveyed articles. The actuating rollers in each set are oriented oblique to the pass-through direction into the transverse belt rollers. This allows the belt rollers to roll along the peripheries of the oblique actuating rollers with little slip.

A variation of the elimination conveyor of FIG. 4 is shown in FIG. 5. In this version, the pass-through portion 32' is laterally narrower at the upstream end 26 of the elimination conveyor than at the downstream end 27, as indicated by oblique demarcation line 88. This arrangement helps wider articles that rest on both the pass-through portion and the elimination portion at the upstream end from being mistakenly stripped away and recirculated. Although the oblique demarcation line 88 in FIG. 5 indicates a linear outer boundary of the pass-through portion, the outer boundary could be curvilinear or rectilinearly stepped by corresponding arrangements of the actuating rollers to realize a laterally narrower pass-through portion at the upstream end of the elimination conveyor.

FIG. 6 shows an elimination conveyor having a pass-through portion formed by a conveyor belt 90 having a high- friction outer surface indicated by friction pads 92. The elimination portion is formed by a parallel conveyor belt 94 with belt rollers 42 oriented to push stripped side-by-sides off the side 35 of the elimination conveyor away from the pass- through portion. This version is effective when pass-through articles are fed onto the elimination conveyor in line with the pass-through region and no further registration, which the previous roller-belt versions are capable of, is required. The factional surface makes it difficult for articles extending laterally onto the oblique rollers in the elimination portion to be pulled away from the pass-through portion. The pass-through belt may alternatively or additionally be provided with perforations, or holes 96, extending through the thickness of the belt. A vacuum system 98, shown in FIG. 7 underlying the pass-through belt 90, draws air through the holes to hold the pass-through articles in place on the belt and prevent them form

being stripped away. An exemplary vacuum system includes a plenum 100 from which air is drawn through a tube 102 by a blower 104.

Another version of a recirculating singulator is depicted in FIG. 8. In this example, the oblique -roller infeed conveyor 10 is preceded by a centering conveyor 110. The centering conveyor is preferably a modular plastic conveyor belt with oblique rollers on each half of the belt oriented to direct articles toward the center. (In FIGS. 8-11, the arrows on portions of the conveying surfaces indicate that articles on those portions of the conveying surface are pushed in the indicated direction by the rotation of activated belt rollers in the portion. The rollers are activated, for example, by bearing surfaces underlying the belts and contacting the belt rollers in those portions of the conveying surfaces. Arrows oblique to the conveying direction represent obliquely arranged rollers; arrows perpendicular to the conveying direction represent rollers oriented to rotate perpendicular to the conveying direction. In many cases, either oblique or perpendicular rollers may be used.)

Articles on the infeed conveyor 10 are registered against its side rail 112 before delivery to an elimination conveyor 114 having a side rail 116. Like the other elimination conveyors, this elimination conveyor has a pass-through portion 118 against the side rail 116 and an elimination portion 120 on the other side. The elimination conveyor may be the same as the elimination conveyor of FIG. 1. But it could also include an upstream portion 122 of the elimination portion in which the rollers are not actuated by an underlying bearing surface. Outer side-by-sides are directed by the downstream portion 123 of the elimination conveyor to a recirculation conveyor 124, which returns eliminated side-by-sides to the centering conveyor 110. The elimination conveyor may be identical to that in FIG. 1, but, instead of oblique rollers in the elimination conveyor, long, transverse rollers, such as those in the belts of FIG. 4, could be used. It would also be possible to use a belt with stacked oblique rollers in which the top roller in the stack supporting the articles rotates in the opposite direction of the lower roller to push articles in the direction opposite to the solid arrow on the elimination conveyor 120 in FIG. 8. Such a dual angled-roller belt could result in a sharper transfer. The side rail 112 of the infeed conveyor is recessed in from the side rail 116 of the elimination conveyor. The amount of recess is selected so that the overlap C of the infeed conveyor and the pass-through portion of the elimination conveyor is roughly the dimension of the width of the narrowest conveyed articles. The movable side rail 112 may be recessed manually or automatically, as indicated by arrow 125, to adjust the overlap C. The automatic adjustment

could be performed in real time in response to an upstream package-width sensor 121, such as an optical or visioning system.

The conveyor shown in FIGS. 9 and 10 are singulators without recirculation. In both of these conveyors, side -by- sides are separated in a separation conveyor 126 identical to the elimination conveyor of FIG. 8, except that the elimination portion delivers outer side -by- sides to a right-hand conveyor 128 advancing parallel to a left-hand conveyor 129 receiving the registered pass-through articles A. The unregistered side -by-sides B are merged back into the flow of registered articles A in a registration conveyor 130. The conveyor of FIG. 10 differs from the conveyor of FIG. 9 by the inclusion of an adjustable side wall 132 along the infeed registration conveyor to adjust for articles of different sizes. The wall is adjusted so that the overlap C of the infeed conveyor 10 and the pass-through portion of the separation conveyor 126 roughly equals the width of the narrowest conveyed articles. The width D of the pass-through portion in this and the other elimination conveyors shown is preferably equal to about the width of the widest conveyed article. The adjustable side wall, whose position may be manually or automatically adjusted, simplifies reconfiguration of the conveyor for articles of different sizes.

The separation or elimination conveyor of FIG. 11 uses bearing surfaces under the belt rollers to reconfigure the demarcation line 134 between the pass-through and elimination portions 136, 137. In this example, six pop-up bearing-surface sets underlie the elimination conveyor and selectively engage the rollers in six associated zones of the conveyor belt. If the widest product width requires a different demarcation 134', bearing-surface sets 138A and 138B pop up into position to actuate the rollers that ride on those bearing- surface sets in the upstream portion. Bearing-surface set 138C is out of engagement with the belt rollers to break up side -by-sides. The three pop-up sets allow for maximum package widths between D (all pop-ups extended and actuating belt rollers) and D' (all pop-ups retracted and deactuating belt rollers). Pop-up bearing sets 140 A-D in the downstream portion of the separation conveyor are adjusted to actuate the oppositely directed rollers to the right side of the demarcation line. Thus, if demarcation line 134' is used, bearing sets 140C and 140D engage the rollers to direct outer side -by-sides B away from registered articles A. And bearing sets 140A and 140B are retracted to deactuate the oppositely directed rollers above them. In this way, they don't interfere with the registration of wide articles against the pass-through rail 116. As an alternative, the pass-through portion 136 could be realized as a roller belt closer to the pass-through rail 116 and a wide belt 142, preferably having a high-friction surface, or a

powered roller conveyor pushing articles toward the pass-through rail as indicated by arrows 144.

What is claimed is: