BACKGROUND

The invention relates generally to power-driven conveyors and more particularly to sorters using roller-top belts.

In the tire industry finished tires leave the inspection area in a mix of types and sizes. The tires are then sorted to different destinations based on their size and type. This has been achieved by interrupting a main conveyor with one or more cross conveyors. Each cross conveyor includes a bidirectional transverse roller-top belt that can sort to the left or the right by the bidirectionally driven belt or across the belt and back onto the main conveyor for further sorting downstream. One example of such a sorting system is described in U.S. Pat. No. 7,306,086, issued December 11, 2007, to Henk W.M. Boelaars. The conveyor system described in that patent requires the roller-top belt to be raised and lowered depending on the tire's assigned destination. If a tire is to be diverted to the right or the left, the roller-top belt is raised above the level of the main conveyor. The roller-top belt is lowered for a tire that is not to be diverted by the cross conveyor. The momentum of a tire entering the cross conveyor is sufficient to push the tire across the roller-top belt onto the next main-conveyor segment, which can then convey the tire downstream. But if the cross conveyor is much wider than the diameter of a tire, the tire's momentum may not be great enough for the tire to cross the cross conveyor.

SUMMARY

One version of a sorting system comprises an infeed conveyor advancing articles from an entrance to an exit in a first direction, a cross conveyor, and first second, and third destinations for the articles. The cross conveyor includes a roller-top conveyor belt that has a first side and an opposite second side spaced apart in the first direction and a first end and an opposite second end. The roller-top conveyor belt is arranged to travel selectively in a second direction perpendicular to the first direction or in a third direction opposite the second direction. Article-supporting belt rollers in the roller-top belt are freely rotatable in the first direction. The first destination is positioned at the second side of the roller-top conveyor belt opposite the infeed conveyor to receive articles passed atop the belt rollers across the roller-top conveyor belt in the first direction. The second destination is positioned at the first end of the roller-top conveyor belt to receive articles discharged off the first end of the roller-top conveyor belt advancing in the second direction. The third destination is positioned at the second end of the roller-top conveyor belt to receive articles discharged off the second end of the roller-top conveyor belt advancing in the third direction. A booster disposed between the exit of the first conveyor and the first side of the cross conveyor is selectively operable to apply a force in the first direction to selected articles exiting the infeed conveyor to push the selected articles across the width of the roller-top conveyor belt to the first destination.

Another version of a sorting conveyor comprises a main conveyor line including a series of main conveyor segments advancing articles in a first direction from an entrance to an exit of each main conveyor segment and a plurality of cross conveyors intersecting the main conveyor line between the main conveyor segments. Each of the cross conveyors includes a roller-top conveyor belt. The roller-top conveyor belt has a first side and an opposite second side spaced apart in the first direction and a first end and an opposite second end. The roller-top conveyor belt is arranged to travel selectively in a second direction perpendicular to the first direction or in a third direction opposite the second direction. Article-supporting belt rollers are freely rotatable in the first direction. First destinations at the first ends of the roller-top conveyor belts receive articles discharged off the first ends of the roller-top conveyor belts advancing in the second direction. Second destinations at the second ends of the roller-top conveyor belts receive articles discharged off the second ends of the roller-top conveyor belt advancing in the third direction. A booster disposed between the exit of each main conveyor segment and the first side of each cross conveyor intersecting the main conveyor line and selectively operable to apply a force in the first direction to selected articles exiting each main conveyor segment to push the selected articles across the width of the roller-top conveyor belt to the entrance of the next main conveyor segment in the main conveyor line.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a sorting section of a sorting conveyor using a bidirectional roller-top cross-conveyor belt with an assist roller.

FIG. 2 is a top plan view of the sorting section of the sorting conveyor of FIG. 1.

FIG. 3 is a side elevation view of the sorting section of the sorting conveyor of FIG. 1. FIG. 4 is a top plan view of a sorting conveyor comprising a series of sorting sections as in FIG. 1.

FIG. 5 is a side elevation view of a sorting section as in FIG. 3 but with linear-motor- driven rollers in place of an assist roller.

FIG. 6 is a side elevation view of a sorting section as in FIG. 3 but with an air manifold in place of an assist roller.

DETAILED DESCRIPTION

A sorting conveyor embodying features of the invention is shown in FIGS. 1-3. The conveyor 10 comprises an infeed conveyor 12, which may be a conveyor belt or a roller conveyor, for example. The infeed conveyor 12 conveys articles, such as tires, in a first conveying direction 14, i.e., in a main conveying direction. The infeed conveyor 12 extends in length in the conveying direction from an entrance 16 to an exit 17. The infeed conveyor 12 feeds articles onto a cross conveyor 18 that includes a roller-top conveyor belt 20, such as an INTRALOX® Series 4400 TRT (transverse roller top) conveyor belt, manufactured and sold by Intralox, L.L.C, of Harahan, Louisiana, U.S.A.

The roller-top conveyor belt 20 has article-supporting rollers 22 on an outer face of the belt. The belt rollers are freely rotatable on axes 24 that are perpendicular to the first conveying direction 14. In that way the belt rollers 22 can rotate freely in the first direction. The roller-top conveyor belt 20 is driven bidirectionally to the left in a second direction 26 and to the right in a third direction 27 by a drive 28 that includes, for example, a motor, a gearbox, a drive shaft, and drive sprockets. The second and third 20 directions 26, 27 are perpendicular to the first conveying direction 14. The roller-top belt 20 extends in length from a first end 30 to an opposite second end 31 and in width from a first side 32 to an opposite second side 33.

The cross conveyor 18 facilitates the sorting of articles received from the infeed conveyor 12 to a selected one of three destinations: (1) straight across the roller-top conveyor belt 20 to an outfeed conveyor 34; (2) left to a left destination 36; or (3) right to a right destination 37. The left and right destinations 36, 37 may be realized as discharge conveyors, chutes, or collection tables, for example. The cross-conveyor drive 28 selectively drives the roller-top conveyor belt to the left destination 36 in the second direction 26 or to the right destination 37 in the third direction 27 depending on the destination assigned to the article. An article not assigned to either the left or the right destination is passed atop the freely rotatable rollers 22 across the roller-top conveyor belt 20 to the outfeed conveyor 34. When an article, such as a tire 38, is destined for the outfeed conveyor 34, the roller-top conveyor belt 20 is stopped. In that way the article can coast over the freely rotatable rollers 22 and onto the outfeed conveyor 34 at the exit 17 of the infeed conveyor 14. A position sensor 39 near the exit 17 detects the presence of an article.

Because the roller-top conveyor belt 20 may be wide or the article may not have enough momentum on exiting the infeed conveyor 12 to cross the cross conveyor 18, a booster in the form of a motorized assist roller 40 is positioned in a gap 41 between the exit 17 of the infeed conveyor and the closer first side 32, the upstream side, of the roller-top conveyor belt. The booster 40 is selectively operable to apply a force in the first direction to selected articles exiting the infeed conveyor 12 to help push them across the width of the cross conveyor 18 and onto the outfeed conveyor 34. The motorized assist roller 40 is driven by a roller drive 42 that is independent of the infeed drive 44 for the infeed conveyor 12. The speed of the motorized assist roller 40 is great enough to ensure that the momentum of an article destined to cross the cross conveyor 18 is sufficient to complete the crossing. If an article is assigned to the left destination 36 or the right destination 37, the speed of the motorized roller 40 can be adjusted to a speed below the speed of the infeed conveyor 12 to decelerate an article so that it does not overshoot the cross conveyor. While an article destined for the left or the right destination 36, 37 is being transferred onto the cross conveyor 18, the roller-top conveyor belt 20 can be stopped or can be moving. As one alternative, the motorized roller's drive 42 can include a clutch, which is engaged to propel an article across the cross conveyor and is disengaged for an article exiting the infeed conveyor 12 that is assigned to the left destination 36 or the right destination 37. As another alternative, the motorized assist roller 40 can be slaved to the infeed conveyor's drive 44 by a drive belt or chain, a pulley or a sprocket, and a clutch, for example.

A longer conveyor system 46 including multiple cross conveyors 18 and sorting destinations is shown in FIG. 4. A main conveyor line 48 includes a series of main conveyor segments 50, such as the infeed and outfeed conveyors 12, 34 of FIGS. 1-3. Like the infeed and outfeed conveyors 12, 34 of FIGS. 1-3, all the main conveyor segments 50 are aligned in the main conveying direction 14. The main conveyor line 48 is intersected by cross conveyors 18 that each provide bilateral sorting destinations 36, 37. A different kind of booster is shown in FIG. 5. This booster 52 is realized as a series of smaller diameter rollers 54 that include magnetic or ferrous material. A linear-motor stator 56 under the rollers 54 produces an electromagnetic flux wave that causes the rollers 54 to rotate to push articles in the first conveying direction 14 across the cross conveyor 18 and onto the outfeed conveyor 34. Rollers 54 with magnetic material form linear synchronous motors with the stator 56; rollers with ferrous materials form linear induction motors with the stator.

Another alternative booster is shown in FIG. 6. This booster is realized as an air manifold 58 supplied pressurized air by an air source 60. Outlets in the top of the manifold direct air jets 62 at articles exiting the infeed conveyor 12. The air jets apply a component of force in the first conveying direction 14 to help push selected articles across the belt rollers 22 on the stopped roller-top belt 20 and onto the outfeed conveyor 34.

The speeds of the drives 28 for the cross conveyors 18, the drives 44 for the main conveyor segments 50, and the drives 42 for the boosters 40 are controlled conventionally by a processor (not shown). The position sensors 39 along the length of the conveyor system report the positions of articles to the processor. Identification sensors, such as bar-code readers, also provide the processor with identifying information for each of the articles so that the processor can determine each article's assigned destination and control the sorting system accordingly.