Conveyor system with distributed article manipulation

A system and method for manipulating articles includes providing a bed having at least one conveying surface. The conveying surface is adapted to move articles in a direction of conveyance from an upstream end to a downstream end of the bed. At least one sensor is provided to determine the position of any articles on the bed. Selected articles are moved in the direction of conveyance at a speed that is generally higher than articles traveling on the bed that have yet to be manipulated and the articles are selectively rotated.

BACKGROUND OF INVENTION

The present invention relates to conveyors, and more particularly to conveyors that manipulate articles. The invention may be applied in many ways, including by way of example, to separate batches of parcels by releasing parcels one at a time. Another application is to manipulate a stream of articles by delivering the articles one at a time with generally controlled gaps between the articles. The articles may also be aligned, such as lengthwise.

Conveyors-such as belt conveyors, roller conveyors, and other types of conveyors are in widespread use today for moving packages, parcels, mail, boxes, and other articles from one place to another. In many situations the articles that are to be carried by the conveyor are initially placed on a conveyor in a manner that is not conducive to being transported and processed by the conveyor system. Typically, the conveyor system is set up to optimally transport articles when they are arranged in a single-file line. In many situations, articles enter a conveyor system on conveyors that are sufficiently wide to accommodate multiple articles positioned side-by-side. In order to effectively process these side-by-side articles, it is desirable to manipulate them such that they are no longer arranged side-by-side, but rather in a single-file line. It may also be desirable to provide controlled gaps between the articles and to orient the articles in a particular manner, such as lengthwise.

In the past, several different types of article manipulators have been used, but these all contain features that have room for improvement. For example, PCT Application Serial No. PCT/US00/11370 (Publication No. WO 01/74693) discloses a hold and release singulator for manipulating items being transported. The hold and release singulator operates in a batch like fashion. In other words, groups of articles are transported onto the singulator, then stopped, and then individually caused to exit the singulator one at a time. After all of the articles have exited the singulator, another batch of articles is moved onto the singulator and the process is repeated. This method may produce an uneven flow of articles exiting the singulator. Further, a batch type manipulation process may not manipulate items as fast as a continuous process.

A continuous type of manipulation process is disclosed in European patent publication EP 0 979 788 82 (application number 99250264.1). However, not all items that enter the singulator of this patent will necessarily be manipulated during their first transport over the manipulation bed. The manipulation device disclosed in this patent includes a return section 70 in which non-manipulated items are re-circulated through the singulator. The re-circulation of these items is generally inefficient. Further, additional floor space must be provided to accommodate the re-circulation conveyors. Oftentimes factory floor space is at a premium and the use of additional space is desirably avoided.

PCT patent application serial no. PCT/US01/13556 (Publication No. WO 01/83339) discloses another existing type of article singulator. While the application discloses several different embodiments of an article singulator, none of these embodiments disclose a singulator which rotates articles. In addition to manipulating articles into a single file line, it is often desirable to rotate the articles such that their longitudinal axis is generally parallel to the longitudinal axis of the conveyor. The articles that enter a singulator are customarily oriented at all different angles. When a singulator is used, such as that disclosed in PCT application PCT/US01/13556, the orientation of the articles are not altered using the singulator. The articles therefore must be processed having skewed angular orientations, or additional means must be provided to rotate the articles to a desired orientation.

In light of the foregoing disadvantages with several of the prior art singulators, the desire can be seen for an improved singulator that overcomes these and other disadvantages.

SUMMARY OF INVENTION

Accordingly, the present invention provides an improved distributed manipulation system that overcomes many of the problems associated with the prior art. Specifically, the distributed manipulation system of the present invention takes up relatively little floor space, processes articles in a rapid manner, does not require recirculation of the items, is relatively quiet, and may process up to 6,000 or more articles per hour wherein the articles may have an average length of about 20 inches. The distributed manipulation system, according to the invention, utilizes a significant number of individual actuators to achieve exceptional dexterity.

A system for manipulating articles generally traveling in a direction of conveyance, according to an aspect of the invention, includes a bed made up of a plurality of conveyor groups, each of the conveyor groups being aligned with each other in the direction of conveyance and each of the conveyor groups made up of a plurality of individual conveyors positioned side-by-side in a direction transverse to the direction of conveyance. The conveyors are adapted to at least partially support articles traveling thereon and to move the articles in the direction of conveyance. At least one sensor is provided that is adapted to determine the position of the articles traveling over the plurality of conveyor groups. A controller is provided in communication with the at least one sensor and the conveyors. The controller is adapted to manipulate articles traveling on the manipulation bed by controlling the speed of the conveyors. The controller is further adapted to rotate an article positioned on the manipulation bed by controlling the speed of selected ones of the conveyors underneath the article such that at least the first one of the selected ones of the conveyors has a different speed than a second one of the selected conveyors.

A method of manipulating articles, according to another aspect of the invention, includes providing a bed having at least one conveying surface adapted to move articles in the direction of conveyance from an upstream end to a downstream end of the bed. The method further includes providing at least one sensor and using the at least one sensor to determine the position of any articles on the bed during at least one moment in time. The method further includes selecting an article on the bed to be manipulated, determining whether the selected article is to be located, and moving the selected article in the direction of conveyance at a speed generally higher than articles traveling on the bed that have yet to be manipulated. If the article is to be rotated, the selected article is rotated.

A system for manipulating articles generally traveling in a direction of conveyance, according to another aspect of the invention, includes a bed having at least one conveying surface adapted to move articles in a direction of conveyance from an upstream end to a downstream end of the bed. At least one sensor is provided that is adapted to determine the position of the articles traveling on the bed. A controller is provided that is in communication with the at least one sensor and the bed. The controller is adapted to manipulate articles traveling on the bed by controlling the speed of the conveying surface. The controller is further adapted to determine if two articles having overlapping alignment in a traverse direction on the bed are on opposite sides of a dividing line extending in the direction of conveyance. The transverse direction is that which is extending in a direction transverse to the direction of conveyance. The controller is adapted to cause the two articles to exit a downstream end of the bed during at least one coincident moment in time if the two articles are on opposite sides of the dividing line.

A method of manipulating articles, according to another aspect of the invention, includes providing a bed having at least one conveying surface adapted to move articles in the direction of conveyance from an upstream end to a downstream end of the bed. The method further includes providing at least one sensor and using the sensor to determine the position of any articles on the bed during at least one moment in time. The method further includes determining whether two articles on the bed have overlapping alignment in a transverse direction and whether the two articles are on opposite sides of a dividing line. The transverse direction is that which extends in a direction transverse to the direction of conveyance. The dividing line extends in the direction of conveyance. If the two articles are on opposite sides of the dividing line and have overlapping transverse alignment, the method provides moving the two articles such that they exit a downstream end of the bed during at least one coincident moment in time.

A system for manipulating articles generally traveling in a direction of conveyance, according to another aspect of the invention, includes a bed comprising a plurality of conveyor groups, the conveyor groups being generally aligned with each other in the direction of conveyance. Each of the conveyor groups consists of a plurality of individual conveyors positioned side-by-side in a direction transverse to the direction of conveyance. The conveyors are adapted to at least partially support articles traveling thereon and to move the articles in the direction of conveyance. At least one sensor is provided that is adapted to determine the position of the articles traveling over the plurality of conveyor groups. A controller is in communication with the at least one sensor and the conveyors. The controller is adapted to manipulated articles traveling on the bed by controlling the speed of the conveyors. The controller is further adapted to be able to control the speed of the conveyors at more than two different non-zero speeds.

As noted above, the various embodiments of the present invention provide a quiet, fast, compact, distributed manipulation system that uses no re-circulation. These and other benefits of the present invention will be apparent to one of ordinary skill in the art upon review of the following specification and accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described with reference to the accompanying drawings wherein the reference numerals in the following written description correspond to like-numbered elements in the accompanying drawings. An article manipulation system20according to a first embodiment of the present invention is depicted inFIGS. 1 and 1A. Article manipulation system20moves articles in a direction of conveyance indicated by arrow22. Article manipulation system20includes a feed conveyor24, a gapper26, a transition conveyor28, a distributed manipulation bed30, and a downstream conveyor32. Article manipulation system20further includes one or more article sensors. In the illustrated embodiment, a plurality of video cameras34and a photo sensor array36are used. However, other configurations of article sensors may be used. By way of example, a plurality of parallel photo sensor arrays36may be spaced along manipulation bed30between groups of individual conveyors42. Alternatively, other types of overhead image capture devices may be used in lieu of cameras34to detect shapes of articles below.

In operation, articles38travel from feed conveyor24onto gapper26. Gapper26enlarges the gaps between articles38in at least a lateral direction (i.e. in a direction transverse to the direction of conveyance22). After passing over gapper26, articles38move onto transition conveyor28. The position, size, and orientation of the articles38is detected by photo sensor array36and/or video cameras34. This information is fed to a controller40which processes this information and controls the speed of the individual conveyors that make up manipulation bed30. Controller40controls the operation of manipulation bed30in such a way that articles38exit manipulation bed30one at a time with a desired gap between the articles. Stated alternatively, manipulation bed30manipulates articles38into a single stream of articles. As will be discussed more herein, controller40can be optionally programmed to manipulate articles into a dual stream of exiting articles, such as will be described in more detail with respect to the embodiment depicted inFIGS. 11–17.

Manipulation bed30is made up of a number of individual conveyors42. In the embodiments ofFIGS. 1 and 1A, conveyors42are belt conveyors. It will, of course, be understood that other types of conveyors42can be used within the scope of the present invention, such as those employing steered or non-steered wheels, rollers, or other types of conveying structures. As illustrated inFIGS. 2A and 2B, each conveyor42of a conveyor unit41includes a belt44that is wrapped around two or more idler rollers46that are generally aligned in a horizontal plane. Belt44is also wrapped around a drive roller48that may be positioned underneath idler rollers46. The arrangement and position of motorized rollers48may be like that depicted inFIG. 1A, or, alternatively, like that depicted inFIGS. 2A and 2B.

InFIGS. 2A and 2B, the position of each drive roller48is alternated between a forward position, illustrated in one of theFIGS. 2A and 2B, and a rearward position, illustrated in the other of theFIGS. 2A and 2B, for each adjacent conveyor42. This provides additional space for the drive rollers48, as well as their associated motors49, and any control wires and/or other structures. Each of the belts orFIG. 2Afurther include a tensioning roller51that is in operative contact with the associated belt. Tensioning rollers51are each biased toward their associated belt by a spring51aoperating on an eccentric51bwhich is operative to move the shaft which rotatably supports the tensioning roller. Spring51aand eccentric51bare located opposite a support plate43from the associated tensioning roller. Tensioning rollers51maintain a constant amount of tension in the belts44due to the bias placed on tensioning rollers51. Preferably, although not necessarily, tensioning rollers51are not aligned in a direction transverse to the direction of conveyance. This provides more space for positioning supporting structure underneath the top surface of belts44.

As an alternative to the belt arrangement depicted inFIGS. 1A,2A and2B, conveyors42could be constructed in a wide variety of different manners. For example, one of end rollers46could be replaced with a drive roller48such that each conveyor42only had two rollers. As another alternative, conveyors42could be made of four rollers, with each roller at the vertex of a square or rectangle, when viewed from the side. As yet another alternative, conveyors42could include a number of support rollers underneath belt44generally in the horizontal plane of conveyance. Conveyors42could also be constructed without a belt44. As one example, conveyors42could be made of one drive roller48connected by one or more O-rings to a series of adjacent rollers. Conveyors42could also be constructed in some of the manners described in PCT Patent Application Serial No. PCT/US01/13556 (Publication No. WO 01/83339), the disclosure of which is hereby incorporated herein in its entirety. Rollers46and48may be supported by support beams50aandbor may be supported in any other conventional manner.

Each drive roller48is in communication with controller40via a communication line52. Communication line52may be a single communication bus that is connected to each drive roller48, or it may be a number of individual communication buses, each of which is connected to some of the drive rollers48. As yet another alternative, communication line52could comprise separate communication lines from controller40to each and every drive roller48. As will be discussed more below, controller40sends speed control commands over communication line52to each of drive rollers48to thereby control the speed at which conveyors42convey products in the direction of conveyance22. Communication line52should allow messages communicated thereover to be transmitted quickly, such as within a few milliseconds, although greater communication times may be used. Controller40may also include additional communications lines (not shown) for communicating with other components of the overall material handling system. Thus, if not enough articles are being supplied to conveyor32, controller40can increase its manipulation rate. Alternatively, it can slow down its manipulation rate where the downstream conveyors are not processing the articles quickly enough. Controller40preferably, although not necessarily, controls the speed of conveyors28and32, in addition to conveyors42of manipulation bed30.

Conveyors42of manipulation bed30are arranged in an array or matrix type of arrangement. Stated alternatively, manipulation bed30is made up of a plurality of columns or groups of conveyors42identified inFIG. 1by the capital letters A–H. Each of these conveyor groups extends in a direction generally transverse to the direction of conveyance22. Manipulation bed30also includes a plurality of conveyor rows identified inFIG. 1by the lower case letters a–k. In the embodiment illustrated inFIG. 1, there are eight groups (columns) of conveyors and eleven rows of conveyors42. Manipulation bed30therefore is made up of88individual conveyors42. Each of these 88 conveyors42includes a drive roller48that has a unique address for communication with controller40. The speed of each individual conveyor42can therefore be individually controlled.

It will be understood that manipulation bed30can include different numbers of groups and rows of conveyors42. In other words, manipulation bed30may include more or less than eight transverse groups of conveyors42. Likewise, manipulation bed30may include fewer or more than eleven rows of conveyors42. The width of each conveyor belt44may range from 10 to 15 centimeters, although widths outside of these ranges can also be used. The length of each conveyor42may also vary from 30 to 100 centimeters, although other lengths can also be used outside of this range. Further, it is not necessary that the size of conveyors42be uniform throughout manipulation bed30. For example, in the embodiment depicted inFIG. 3, the three downstream-most conveyor groups have a length that is longer than the four upstream-most transverse conveyor groups. Other variations are also possible in the size and shape of conveyors42.

Gapper26is an optional component that may be utilized to increase the gaps between articles. The gaps may be increased in a direction transverse to the direction of conveyance22, a lateral direction, or both. Increasing this gap will help video cameras34and/or photo sensor array36to distinguish the boundaries of individual articles38. Gapper26, in one embodiment, may include a number of individual belt conveyors54. Each belt conveyor54is arranged at an angle with respect to the direction of conveyance22. The magnitude of this angle increases from the center of gapper26towards its outer edges. Thus, inFIG. 1belt conveyor54D is angled slightly outwardly from the center of gapper26. Belt conveyor54C is angled outwardly to a greater extent. Belt54B is angled outwardly even more and belt54A is angled outwardly to the greatest extent. Belts54E–H are shown with angles that are mirror images of the angles of belts54A–D. As articles38travel over gapper26, the angled nature of belt conveyors54exerts a transverse force on articles38. This transverse force tends to create transverse gaps between the articles, or increase any pre-existing transverse gaps.

In order to ensure that a sufficient longitudinal gap exists between articles38so that video cameras34and/or sensor array36can distinguish between individual articles, gapper26may operate at a higher longitudinal speed than feed conveyor24. This higher longitudinal speed will cause articles traveling from feed conveyor24onto gapper26to have their longitudinal gaps increase. The combination of feed conveyor24and the increased longitudinal speed of gapper26ensures that articles38will be sufficiently separated in both the lateral and longitudinal directions from each other so that they can be properly detected and processed by sensor array36and/or video cameras34. The construction of gapper26may vary substantially from that depicted herein. For example, alternative constructions using wheels or other non-belt conveying means can be used.

Transition conveyor28may include a single belt56, or it may be constructed with multiple belts, such as is illustrated inFIGS. 1–2. As illustrated, transition conveyor28includes two belts56that are each wrapped around a pair of end rollers58. One of each pair of end rollers58may be a powered roller which powers the movement of belt56in the direction of conveyance22. Transition conveyor28may alternatively be made up of a number of additional belts56, such as is illustrated in the embodiment depicted inFIG. 3. By using multiple smaller belts56, rather than one or a few large belts56, the cost of manufacturing transition conveyor28may be decreased. Transition conveyor28is an optional component and may be omitted, especially in article manipulation systems in which no photo-sensor array, such as photo-sensor array36, is used.

Photo sensor array36is an optional sensor that, if used, is preferably placed approximately in the middle of transition conveyor28. Array36should be positioned far enough downstream of gapper26such that any residual sliding or rotating of articles that may have been caused by gapper26has stopped. The position of the articles detected by array36will therefore not unknowingly change downstream of array36. Photo sensor array36consists of a plurality of individual photo sensors that are arranged to detect light, or other electromagnetic energy, that is emitted downwardly onto the surface of transition conveyor28and array36. This light may be fluorescent light that is emitted from a fluorescent light bulb (not shown) positioned above array36at a sufficient height to allow articles38to travel underneath the light bulb while on transition conveyor28. Photo sensor array36includes sensors for detecting the light energy. Because the light, or other energy, will be obscured by articles38traveling over array36, photo sensor array36can distinguish between articles38and an empty space on transition conveyor28. Photo sensor array36preferably, although not necessarily, comprises an array of sensors that are closely packed together and extend in a transverse direction. The individual sensors of array36may be positioned within five millimeters or less of each other, although other spacing may be used. The sensor array36may be a conventional product such as is manufactured by Kore Computing of Comstock Park, Mich. or SICK, Inc. of Bloomington, Minn. The outputs of each sensor in array36are preferably scanned multiple times per second with sufficient speed to allow the size, orientation, and position of articles38to be detected as they pass above array36. This information is passed from array36to controller40by way of a communications line60. Controller40uses this information, along with information from video cameras34if so equipped, to determine which will be the next article to be manipulated, whether it will need to be rotated, and to make other determinations as will be discussed in more detail below.

In the embodiments illustrated inFIGS. 1 and 1A, there are three video cameras34a–c. It will be understood by those skilled in the art that a different number of video cameras34can be used to practice the present invention. As previously disclosed, other article sensors, such as other types of overhead article shape sensors or additional photo sensor arrays spaced along the bed in the direction of article flow, may be used in the alternative. Video cameras34a–care positioned above manipulation bed30and transition conveyor28. Video cameras34a–cthus detect the movement of articles38on transition conveyor28and manipulation bed30. Further, video cameras34a–cdetermine the position and/or shape of each article38with sufficient accuracy to allow controller40to properly manipulate articles on manipulation bed30. Video cameras34a–ccommunicate with controller40over a communications line62. Video cameras34a–cmay be used in conjunction with photo-array36, or they may be used without photo-array36. Alternatively, the article manipulation system may use only a photo-array36without any video cameras34.

Controller40, which may be a conventional programmable logic controller (PLC) a personal computer, or any other type of computer, receives and processes the information from video cameras34a–cand/or photo sensor array36. Controller40includes conventional video image processing software that processes the information received from video cameras34a–c. This software allows controller40to know precisely where each article38is positioned on either transition conveyor28or manipulation bed30. In particular, when articles38are positioned on manipulation bed30, the output from video cameras34a–callows controller40to determine which specific conveyors42are underneath each of the articles38on manipulation bed30. Controller40then sends appropriate speed commands over communications line52to control the speed of individual conveyors42to effectuate manipulation of article38.

A diverter/merge conveyor64may be positioned adjacent the downstream end of manipulation bed30. Diverter/merge conveyor64may be used to perform several different functions, depending upon the desired application. In one application, diverter/merge conveyor64simply directs the incoming articles from manipulation bed30toward a generally uniform position on conveyor64with respect to its side66aandb. This is a useful operation where the conveyor downstream of conveyor64has a narrower width than that of conveyor64. In order to ensure articles exiting conveyor64will be aligned with this narrower width, conveyor64steers the articles traveling thereon so that they will be aligned with the downstream conveyor.

In an alternative application, diverter/merge conveyor64may be used to steer articles traveling thereon to two or more downstream conveyors, each of which may, in turn, lead to a separate conventional sortation apparatus. In the embodiment depicted inFIG. 3A, diverter/merge conveyor64is a conventional steered wheel conveyor. As illustrated inFIG. 3A, conveyor64includes a plurality of individually steered wheels68. Each wheel68rotates about a horizontal axis. The orientation of this horizontal axis can be changed between an orientation parallel to the direction of conveyance22to a horizontal direction that is skew to this. The changing of these horizontal axes can be accomplished in a conventional manner through the use of actuators70, or other devices. Typically, each column of wheels68that extends from side66a–bare controlled in unison. The individual columns can be controlled independently from other columns, if desired. The control of conveyor64may be carried out by a local controller that is part of conveyor64, or it may be controlled by controller40. The rotation of wheels68exerts a force against articles traveling on conveyor64. The direction of this force is dependent upon the horizontal orientation of the horizontal axes of the wheels68. By appropriately changing the orientation of these horizontal axes, the side-to-side position of articles traveling on conveyor64can be altered as desired.

Controller40controls the manipulation of articles38that takes place on manipulation bed30. Controller40can be programmed to manipulate articles in a variety of different manners. A first method for manipulating articles is depicted inFIGS. 4–10. A second method of manipulating articles is depicted inFIGS. 12–17. In the first method, articles traveling on manipulation bed30may be rotated so that their longitudinal axis is closer to being parallel to the direction of conveyance. Regardless of whether articles are rotated or not, this first method of control causes the articles to exit one at a time from the downstream end of manipulation bed30. In the second manner of manipulation depicted inFIGS. 12–17, article rotation may or may not be included as part of the programming. Regardless of whether rotation is included as part of the programming of controller40, the second method involves allowing articles to simultaneously exit the downstream end of manipulation bed30provided that the articles are sufficiently spaced apart laterally. These two methods will be described in more detail below.

Referring now toFIG. 4, a plurality of articles38are shown initially positioned on transition conveyor28. Articles38have been individually identified by capital letters A–G. At the moment in time depicted inFIG. 4, video cameras34and/or photo sensor array36have provided controller40with sufficient information for it to determine the locations of articles A–G. Controller40selects the downstream-most article that can be advanced without colliding with an adjacent article. In the illustration ofFIG. 4, article B has a corner that is the furthest downstream of any other part of the illustrated articles. However, if article B were to be advanced in the direction of conveyance, it would collide with article A. Therefore, controller40selects article A as the first article to be manipulated. Controller40therefore determines which row of conveyors42will be positioned under article A as it travels over manipulation bed30.

The individual conveyors42of manipulation bed30are generally controlled to operate at one of two different speeds. As will be discussed more below, when rotation of articles is desired, other speeds may be used other than these two different speeds. The first speed is illustrated inFIG. 4as Vuand refers to the velocity at the upstream end of manipulation bed30. Speed Vumay also be the velocity of transition conveyor28. The other speed is illustrated inFIG. 4as Vd, and refers to the downstream velocity of manipulation bed30. Speed Vdmay also be the speed of downstream conveyor32. A boundary line72separates those conveyors42that are operating at speeds Vdfrom those operating at the speed Vu. The conveyors operating at speeds Vdare also shaded inFIGS. 4–10for greater clarity. Speed Vdis greater than speed Vu. Therefore, articles traveling on conveyors42operating at speed Vdwill separate themselves from other articles on conveyors42traveling at speed Vu.

It will be understood that controller40may control the speeds of individual conveyors42so that articles transitioning across boundary72from speed Vuto speed Vdwill have their instantaneous accelerations reduced or minimized. In other words, a conveyor42that is to operate at speed Vd, and that is downstream of an adjacent conveyor traveling at speed Vu, may initially have its speed set to match, or come close to, the speed Vuof the adjacent upstream conveyor. After the article has transitioned onto the downstream conveyor42, its speed is increased to that of Vd. In this manner, article slippage on the conveyor belts, noise from this slippage, and wear on the belts is reduced. Conveyor belts42therefore may be operable at two or more non-zero speeds and may be operable at essentially infinitely variable speeds. The shaded areas in the accompanying drawings representing conveyors42operating at speeds Vdare thus somewhat generalized to illustrate the underlying control logic used by controller40. Individual belts within the shaded areas may operate at speeds other than Vd, particularly those belts involved in transitioning an article across boundary line72. Unoccupied belts downstream of those operating at Vdalso may not operate at this same speed until the article traveling at speed Vdis actually delivered to these unoccupied belts.

Controller40operates to alter boundary line72as articles38travel over manipulation bed30such that articles are manipulated. With the exception of the rotation of articles, the algorithms that controller40follows in altering the position of boundary line72inFIGS. 4–10may be the same as those disclosed in International Patent Application Serial No. PCT/US01/13556, the disclosure of which is hereby incorporated herein by reference.

As article A transitions from transition conveyor28to manipulation bed30inFIG. 4, the speed of article A will increase relative to the other articles at the moment that article A is sufficiently on manipulation bed30to be controlled by the conveyors42underneath it. The longitudinal space between article A and the other articles will therefore begin to increase after article A's speed transitions from that of Vuto Vd. At the moment in time illustrated byFIG. 5, the individual conveyors42that are underneath article A are conveyors42Af and42Ag. A small portion of article B also overlies conveyor42Af. Because this portion is so small relative to the size of article B, controller40determines that the operation of conveyor42Af at speed Vdwill not affect the position or orientation of article B.

If article B inFIG. 5extended further on to conveyor42Af, then controller40would only run conveyors42Af and Ag at speed Vduntil article B arrived at either or both of these conveyors. At that moment in time, controller40would decrease the speed of these two conveyors to Vu. The longitudinal gap between article A and article B would therefore only be increased for the time during which article A was traveling at speed Vdwhile article B was traveling at speed Vu. If more longitudinal gap were desired between articles A and B than was created by operating conveyors42Af and Ag at speed Vd, an increased longitudinal gap could be created by operating conveyors42Bf and Bg at speed Vdwhile article B had not entered onto any of these conveyors. Similar longitudinal gaps between articles A and B could be created using conveyors42Cf and Cg, as well as the conveyors in rows f and g and columns D, E, F, and G.

FIG. 6illustrates a moment in time subsequent to that illustrated inFIG. 5. At this moment in time, controller40has changed the speed of conveyors Af and Ag back to that of Vu. Controller40has determined that the next article to be manipulated will be article B. By returning conveyors42Af and Ag to speed Vu, the relative position of article D with respect to the other articles, such as article B will not be altered. The information that controller40receives from video cameras34a–cand photo sensor36indicates that article A has a skew orientation relative to the sides of74A and B of manipulation bed30. Video cameras34and sensor array36provide sufficient information to controller40for it to determine this angular orientation with respect to side74. If this angular orientation exceeds a predetermined value, controller40determines that the article should be rotated. The article is then rotated so that this angle is decreased. This rotation of articles helps the downstream processing of articles on the conveying system.

In general, controller40may be programmed to rotate all articles whose longitudinal orientation is greater than +/−15° with respect to the direction of conveyance. Other thresholds may be chosen. For square articles greater than a given size, such as 250 mm×250 mm, controller40may be programmed to rotate these articles so that one of the sides of the article is less skew with respect to the direction of conveyance. For square articles smaller than this given size, controller40may be programmed to not rotate the articles, regardless of their degree of skew. Oblong or irregularly shaped articles may be processed with or without rotation, depending on their aspect ratio. If the aspect ratio exceeds a given threshold, then rotation would more likely be carried out. Where the aspect ratio does not exceed a given threshold, no rotation would be carried out.

In the illustrated embodiment, controller40determines that article A has such a skew orientation that it will be rotated. Controller40will rotate article A in a clockwise direction indicated by arrow76inFIG. 6. This rotation is accomplished by increasing the speed of conveyor42Bf relative to that of conveyor42Bg. Controlled speed differences between the conveyors in rows f and g that underlie article A are maintained in each conveyor column until rotation has taken place. Therefore, as illustrated inFIG. 7, conveyor42Cf and Cg will operate with a speed difference, for at least an initial period of time. InFIG. 7, conveyor42Cf is operating at a speed Vd+K. Conveyor42Cg is operating at a speed Vd−K. This difference is speed causes article A to rotate such that its sides become less skewed with respect to sides74aandbof manipulation bed30. The precise value of the variable K can be varied as desired. In order to more quickly rotate an article, the value K should be higher, as would be known by one with ordinary skill in the art. The value of K may vary for each individual article, depending on the degree of skewness of the article, the size of the article, and other factors. The value of K may also vary with respect to time during the rotation of a given article. This time variation may include a gradual ramping up to a peak value of K, followed by a gradual descending back to a zero value during rotation so that instantaneous accelerations of the article are reduced. Other types of time-varying changes to the value of K may also be implemented. Controller40may be programmed to rotate articles generally about their center position. Video cameras34can be used to monitor the actual article rotation to provide feedback to controller40during the rotation process. This feedback is used by controller40to control the rotation process more accurately.

As illustrated inFIG. 8, the speed of the conveyors42underneath article A are reset to Vdafter the rotation of the article is complete. Article A will then continue to travel down manipulation bed at Vd. The speed of the conveyors under article B will be increased to that of Vdwhen a desired longitudinal gap has been achieved between articles A and B. This gap may be set anywhere from zero to whatever spacing is desired for articles in a particular application. For articles that will not be rotated, the gap is the longitudinal distance between the upstream end of the leading article and the downstream end of the trailing article. For situations in which one or more articles will be rotated, the gap is the longitudinal distance, after rotation, between the upstream end of the leading article and the downstream end of the trailing article. As illustrated inFIG. 8, the desired gap is less than that between the upstream end of article A and the downstream end of article B because controller40has determined that article B will be rotated. The desired gap is therefore the longitudinal separation between articles A and B that will be present after article B has been rotated. Controller40computes this gap and may use feedback from cameras34to verify the rotation of the articles. The size of the desired gap can be dynamically changed by controller40. Once this desired gap has been achieved, conveyors42in rows b–e will be set to speed Vdfor conveyor columns B–F. Article B will therefore begin to longitudinally separate from the other articles traveling at speed Vu.

As illustrated inFIG. 9, the rotation of article B is carried out in a similar manner to that of article A. Specifically, the speed of the conveyors in rows b and c underneath article B are increased relative to the speed of conveyors42in rows d and e. As illustrated inFIG. 9, conveyors42Db and Eb are operating at a speed Vd+L. Conveyors42Dc and42Ec are set at a speed Vd+K. Conveyors42Dd and Ed are set at a speed Vd−K. Conveyors42De and Ee are set at a speed Vd−L. These speeds K and L may be set as proportional to the lateral distance away from the point of rotation on article B. Thus, the variable L will have a greater value than the variable K. The value of L, like the value of K, may vary between articles and it may vary with time over the course of rotating a given article. The varying speeds of the conveyors underlining article B will thus cause article B to rotate in a clockwise direction. After rotation, it will have the desired longitudinal gap between itself and article A.

As is also illustrated inFIG. 9, controller40will increase the speed of the conveyors underneath article C when a desired gap is obtained between article B (after rotation) and article C. Because article C will not be rotated, the conveyor42underneath article C will simply be increased to speed Vd. Once article C has advanced down manipulation bed30such that a desired gap is obtained between articles C and D, the conveyors42underlying article D will have their speed increased to that of Vdby controller40, as is illustrated inFIG. 10. Controller40will continue to increase the speed of the underlying conveyors of each article as desired gaps are obtained. Thus, controller40will increase the speeds of the conveyors42underlying article E after a desired gap is obtained. Because article E will be rotated, this desired gap will be the gap created after rotation. Controller40will continue to operate in a similar fashion for articles F and G, and all subsequent articles.

While the operation of manipulation bed30and controller40has been illustrated with respect to only seven articles, it will be understood that manipulation bed30and controller40may operate substantially continuously. Alternatively, the operation of manipulation bed30may be a batch type of operation. As illustrated inFIG. 10, article A has been manipulated onto downstream conveyor32. At later moments in time, articles B, C, and D, as well as the rest of the articles will arrive at downstream conveyor32in a manipulated fashion. As described previously, downstream conveyor32may be constructed to alter the lateral position of the manipulated articles with respect to sides66aandb.

FIG. 11illustrates an alternative embodiment of article manipulation system20′ according to another aspect of the present invention. Article manipulation system20′ differs from that of article manipulation system20in that a pair of branch conveyors78aandbare positioned downstream of downstream conveyor32. Articles exiting downstream conveyor32will therefore travel down one of branch conveyor78aor78b. Article manipulation system20′ includes a feed conveyor24, a gapper26, a transition conveyor28, a manipulation bed30, and a downstream conveyor32. Further, although not illustrated inFIG. 11, it includes video cameras34and/or a photo sensor array36(also not illustrated). Transition conveyor28may be made up of a number of separate belts in order to minimize the costs of manufacturing transition conveyor28. The operation of article manipulation system20′ is illustrated inFIGS. 12–17, which are described in more detail below.

As a general matter, manipulation bed30of article manipulation system20′ operates generally in a similar manner as has been previously described with respect to article manipulation system20. Article manipulation system20′ differs from article manipulation system20in that article manipulation system20′ includes an imaginary dividing line80. Imaginary dividing line80is located at a lateral position with respect to sides74aandbof manipulation bed30that is collinear with the separation line between branch conveyor78aandb. Controller40is programmed to allow multiple articles to exit from manipulation bed30at the same time in those instances where the multiple articles are on opposite sides of dividing line80, or where the articles can be separated by conveyor32so as to travel down each of conveyors78aandb. Thus, article manipulation system20′ manipulates articles, where possible, into two streams of articles. This is described in more detail below.

Controller40determines that article A will be the first article to be manipulated. This determination is made using the same criteria as described above with respect to article manipulation system20. Accordingly, controller40increases the speed of those individual conveyors42that are in rows f and g to that of Vd. The conveyors in these two rows are the conveyors that are laterally in line with article A. Therefore, when article A enters onto manipulation bed30, its speed relative to the other articles will increase, and therefore its longitudinal separation. As illustrated inFIGS. 12 and 13, article A overlies dividing line80. Thus, a portion of article A lies above dividing line80(toward side74a) and a portion of article A lies below dividing line80(toward side74b). Controller40therefore determines that article A will be manipulated by itself; that is without simultaneously manipulating any other article. Controller40of article manipulation system20′ is programmed to determine whether the next article to be manipulated is either fully above or below dividing line80. If controller40of article manipulation system20′ is further adapted to rotate articles, then the determination of whether an article is below or above dividing line80is made with respect to the article's post-rotation position.

As illustrated inFIG. 14, the longitudinal separation of article A from the other articles will increase. Controller40reduces the speed of conveyors42Af and Ag after article A has exited from these conveyors. This reduction in speed back to speed Vuprevents article D from having its position and/or orientation changed with respect to the other articles traveling at speed Vu. Controller40determines that the next article to be manipulated is article B. Controller40determines that article B is fully above dividing line80. Therefore, controller40next determines if article B has any overlapping alignment in a transverse direction with another article (FIG. 15). This determination is made by extending the trailing and leading edges of article B perpendicularly toward one of sides74aandb. The trailing and leading edges of article C are also extended toward the same side. To the extent the area between the trailing and leading edges of each respective package overlaps, controller40concludes that there is overlapping alignment in a direction transverse to the direction of conveyance. In the example illustrated inFIG. 15, controller40determines that articles B and C have overlapping transverse alignment. Controller40therefore next determines whether article C is positioned on an opposite side of dividing line80as article B. In the illustrated case, it is. Therefore, controller40determines that articles B and C can be simultaneously advanced toward the downstream end of manipulation bed30. Articles B and C will thus exit manipulation bed30at a coincident moment in time. Because they are positioned on opposite sides of the dividing line80, article B will end up proceeding down branch conveyor78a, while article C will eventually move down branch conveyor78b. By simultaneously advancing articles B and C together, manipulation bed30can increase its throughput. If article C had not been on an opposite side of dividing line80, then controller40would have changed the speeds of the conveyors under article B such that it would have advanced ahead of article C.

As illustrated inFIG. 16, the individual conveyors42underlying article D will have their speed increased to that of Vdwhen a desired gap is created between either article B or article C. Controller40will determine which of articles B or C to use as a reference for the gap between it and article D on the basis of which branch conveyor78article D will be traveling down. Specifically, because a majority of article D is positioned below dividing line80, downstream conveyor32will likely divert article C down branch conveyor78b. Therefore, controller40will wait until the gap between articles C and D reaches a desired gap before increasing the speed of the conveyors42underneath article D to that of Vd. Controller40therefore determines the desired gap between articles that will successively travel down the same branch conveyor78.

As illustrated inFIG. 17, controller40will determine that article E is the next article to be manipulated. Controller40will determine that article E is completely on one side of dividing line80. Controller40will therefore determine whether article E has any overlapping alignment with another article. Because article E does indeed have overlapping alignment with article F (seeFIG. 16), controller40will next determine whether article F is completely below dividing line80. Because article F is not completely below dividing line80, articles E and F cannot be manipulated simultaneously. This is because divert/merge conveyor64does not have the means to separate articles E and F laterally such that one of them will travel down conveyor78aand the other down conveyor78b. Therefore, controller40will increase the speeds of conveyors42underneath article E to that of Vd. As illustrated inFIG. 17this will increase the longitudinal spacing between articles E and F. If a divert/merge conveyor64is used that allows the lateral spacing between articles thereon to be controlled, then it would be possible to manipulate articles E and F simultaneously. Conveyor64would separate these articles so that they exited conveyor64on opposite sides of dividing line80, thereby directing them to opposite branch conveyors78aandb.

Controller40next determines that article F is completely to one side of dividing line80and that it has overlapping transverse alignment with respect to article G. Furthermore, controller40determines that article G is completely to the other side of dividing line80. Therefore, controller40will simultaneously advance articles F and G so that they can be manipulated together, in the same manner that articles B and C were manipulated.

Manipulation bed30of article manipulation system20′ may also operate in a continuous fashion or a batch fashion, just as manipulation bed30of article manipulation system20. As has been noted previously, controller40of article manipulation system20′ may optionally include programming that allows articles to be rotated in a manner described with respect toFIGS. 4–10. When controller40is programmed in this way, controller40makes all of its determinations with respect to dividing line80based on the post-rotational position of articles. In other words, controller40determines what positions articles will be in after they are rotated. These post-rotation positions are then used to determine whether an article is completely on one side or another of dividing line80as well as whether or not it has any transverse alignment with another article.

The gaps between articles exiting manipulation bed30of article manipulation system20′ may be dynamically controlled by controller40. Controller40may alter these gaps based on information it receives from other components in the overall conveyor or material handling system. Alternatively, the gaps may be adjusted by an operator inputting this information into controller40. In article manipulation system20′, the desired gaps are determined with respect to articles that will travel down the same branch conveyor78aorb. Thus, a pair of articles may exit bed30with less than the desired longitudinal gap between the two articles if they are to be sent down opposite ones of conveyors78aandb. In such a case, it is the longitudinal gap between each article and the downstream article on the same destination conveyor78aorbthat is controlled, not the longitudinal gap between each article in the pair.

FIGS. 18 and 19depict two alternative implementations of an article manipulation system according to the present invention. In the embodiment ofFIG. 18, the article manipulation system20″ includes a bulk conveyor24, photo-sensor array36, transition conveyor28, manipulation bed82, merge conveyor82, and take-away conveyor84. Article manipulation system20″ does not include a gapper26. Photo-sensor array36is positioned at an upstream end of transition conveyor28, rather than in a center region of conveyor28. Merge conveyor82may include a merge bar86that is angled with respect to the direction of conveyance. Merge bar86causes articles traveling on merge conveyor82that come into contact with it to be pushed toward the side of conveyor82that is aligned with take-away conveyor84. Merge conveyor82thus does not need to use wheels, or other types of actuators, to merge incoming article streams into exiting article streams having a smaller lateral expanse. Article manipulation system20″ may further include a vision processor88that is discrete from controller40. Processor88may pre-process the raw signals received from cameras34and/or sensor array36before passing the sensed information onto controller40. Processor88may include any suitable microprocessor and associated hardware components.

Article manipulation system20′″ ofFIG. 19includes the same components as article manipulation system20″, and further includes a gapper26. Photo-sensor array36is positioned in the center region of transition conveyor28. Article manipulation system20′″ includes a merge conveyor82that may be the same as the merge conveyor82of article manipulation system20″.

While the present invention has been described in terms of several preferred embodiments depicted in the drawings and discussed in the above specification, it will be understood by one skilled in the art that the present invention is not limited to these particular embodiments, but includes any and all such modifications that are within the spirit and scope of the present invention as defined in the appended claims.