WO2001051223A2

WO2001051223A2 - Automated sortation system for coded articles or packages and related method

Info

Publication number: WO2001051223A2
Application number: PCT/US2000/032859
Authority: WO
Inventors: James L. Layne; Michael D. Mcdaniel
Original assignee: Span Tech Llc
Priority date: 2000-01-11
Filing date: 2000-12-04
Publication date: 2001-07-19
Also published as: WO2001051223A3

Abstract

A sortation system and related method for sorting coded articles, packages, or the like includes a plurality of carriers that are driven in an endless path around a carousel. The carousel is defined by a frame that also forms a guide track for the carriers. Each carrier includes a ledge for supporting an article and an ejector flap. A scanner reads coded information from the articles or packages and determines the proper distribution station for ejection as the carriers pass. An actuator causes the ejector flap to sweep across the ledge and positively eject the article. To facilitate the automated loading of each article, each carrier may also include a conveyor pan that is capable of being tilted to a substantially horizontal position. In this position, fingers projecting from the pan interleave with a grate and sweep a coded article onto the pan for later sortation and distribution. The pan is then returned to the home position and the article held thereon ejected at the selected distribution station.

Description

AUTOMATED SORTATION SYSTEM FOR CODED ARTICLES OR PACKAGES AND RELATED METHOD

Technical Field

The present invention relates to sorting of articles, packages, or the like for later distribution and, more particularly, to an automated sortation system and related methods for receiving coded articles or packages and reliably ejecting them at selected distribution stations.

Background of the Invention

During the past few years, the number of businesses engaging in the retail sale of goods thorough mail-order or "e-commerce," where the entire operation involves warehousing, packing, and shipping items that customers order over the telephone or online, has greatly increased. In addition to those solely engaged in such commerce, many businesses maintain an online sales presence or mail-order catalog to remain competitive, but also continue to sell wares through retail stores or other outlets, which are usually supplied by regional distribution warehouses. To keep the ever-increasing number of online or mail-order customers satisfied by providing prompt service and to insure that retail stores remain fully stocked, there is a need for systems and methods capable of efficiently sorting and distributing the ever increasing volume of articles sold in a relatively short amount of time.

Whether engaging in "on-line," mail-order, or conventional commerce, most retailers depend on contractors or a central receiving warehouse to supply one or more sorting terminals or hubs. Each terminal or hub sorts the articles according to selected parameters, such as those going to a particular customer, retailer, or regional destination for sub-warehousing and redistribution. Necessarily, the systems employed must not only be capable of processing the articles or packages within defined time parameters, but also with virtually zero-error tolerance. Indeed, in response to the continuously increasing number of articles sold and packages distributed directly to the consumer, the sortation systems must operate much faster, as well as without errors and generally more efficiently, than just a few years ago. Providing a system having enhanced adaptability to accommodate fluctuations in need/demand, in addition to one that is simpler and less expensive to purchase and operate, is also desirable.

Since as early as the 1960's, conventional sortation systems have employed wheeled tilt tray units that receive, transport and deposit packages at selected distribution stations. U.S. Patent Nos. 3,167,192 to Harrison et al. and 3,327,836 to Burt both disclose sortation systems that utilize a number of tilt tray units propelled along a carousel-type track by an endless conveyor chain. Timers and magnetic readers are used to actuate solenoids to tilt the trays to one side upon reaching their destination, such that the articles or packages are ejected into the appropriate bin.

One significant limitation arising from the use of such tilt trays is that the articles or packages are not always reliably ejected leading to errors and low efficiency. One problem arises if the article or package is heavy, flimsy, wet, or has a high friction contact surface. In this instance, it may not be fully ejected by simply tilting the tray in the usual manner. Of course, this potentially leads to the problem of delivery of articles or packages to incorrect destinations and/or cartons containing fewer than all the articles or packages desired or requested, much to the disappointment of the retailer or customer expecting the delivery. Thus, inherent in the use of these prior art systems, insuring that articles are reliably ejected from the tilt trays to the proper bin and/or that the receptacles or delivery cartons contain the proper number of articles, still requires frequent human intervention. This of course increases the time and expense associated with sorting, distributing and shipping the articles. Another shortcoming is in the area of loading of the articles or packages on the tilt trays. Typically, an infeed conveyor is used for this purpose. In its simplest form, the infeed conveyor simply drops the articles directly onto the tilt tray. Such an arrangement is inherently unreliable, since there is little assurance that as the article falls onto the tray, it remains seated on the tray, rather than bouncing off it. Such misfed articles or packages can sometimes lead to deleterious jams, which require costly system downtime to clear. Even if a jam is avoided, articles falling from the tilt trays during loading further contribute to the misdelivery problems previously mentioned.

A more recent sortation system described in U.S. Patent

4,832,204 to Handy et al. integrates these prior art tilt tray sortation systems with complicated scanning equipment and computer control in an attempt to improve overall system speed and efficiency. Despite the successful integration of these components into a supposedly more modern and state of the art system, and with much greater complexity and at an increased cost, the system of the '204 patent still fails to improve the basic sortation apparatus and method. In essence, businesses that rely on such sortation systems are calling for a move away from the continued reliance on the complex, expensive, and unreliable tilt tray systems, such as in the '204 patent. At the same time, they are demanding significant increases in the overall speed, efficiency and adaptability of the sortation system.

Thus, an important aspect of the effort to improve this technology is to provide an automated sortation system and related method that is capable of sufficiently sorting and distributing an increasing volume of articles or other packages within a defined shorter period of time. The desired approach should be to eliminate the complexity, especially with regard to the tilt trays, and instead go to a simple series of carriers that can reliably support and hold the articles as they are driven around a carousel past the distribution stations. A simple ejector for positively and effectively discharging the articles from the carriers without tilting at the selected distribution station is desirable. Improving the manner of automatically loading the articles or packages onto the carriers in a reliable fashion to obviate the deleterious bouncing is also necessary. Overall, these improvements would result in increased system speed, efficiency and adaptability, as well as a lower cost of operation and maintenance. The reliability afforded would also keep the direct online customers, as well as the retailers, fully satisfied.

Summary of the Invention

Accordingly, it is a primary object of the present invention to provide a novel automated sortation system and related method particularly adapted to improve operating speed and efficiency, including to insure reliable ejection of articles, packages, or the like, in order to overcome the limitations of the prior art.

Another object of the present invention is to provide a simplified automated sortation system particularly adapted to utilize a plurality of carriers driven in an endless path around a carousel that effectively and reliably eject coded articles or packages at selected distribution stations. Still another object of the present invention is to provide an automated sortation system that utilizes a detector to read coded information on articles or other packages and a controller to determine a proper distribution station for ej ection of the articles or packages according to a selected parameter of the coded information.

A further object of the present invention is to provide an automated loading station as part of the system that reliably places an article or other package directly on each carrier for later sortation and distribution.

Another object of the present invention is to provide a sortation method including positioning the articles or other packages on one of a plurality of carriers driven in an endless path around a carousel, scanning the articles to read a selected parameter, and ejecting the packages at the proper distribution station according to the selected parameter.

Yet a further object of the present invention is to provide a method of automatically loading an article onto a passing carrier in a reliable fashion.

Additional objects, advantages, and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as described herein, an improved system for automatically sorting and distributing coded articles or packages according to a selected parameter is provided. The sortation system includes a plurality of carriers for receiving and carrying the coded articles or packages. The carriers are driven along an endless path around a carousel past a plurality of individual distribution stations. Each carrier includes a ledge for supporting at least one of the coded articles. A detector in the form of a scanner reads the code on each article or package as each carrier passes. When the coded article having the selected parameter reaches a corresponding selected distribution station, a controller signals an actuator to eject the package from the carrier. Positive and reliable ejection of each coded article is effected at the desired instant by an ejector flap on the carrier that sweeps across the support ledge. While the preferred embodiment of the present invention is described for use in conjunction with sorting articles or packages, other like objects, such as letters or other parcels of mail, can be sorted utilizing the same principles in accordance with the broadest aspects of the invention.

The carousel is defined by a frame that includes a guide track foimed of opposed guide rails on which the carriers travel. The plurality of distribution stations are positioned around the frame, each for receiving coded articles having a common parameter, such as those for delivery to a particular customer, retail store, or regional distribution warehouse. The distribution stations may include receptacles, chutes, or any other means for receiving the coded article or package from the carrier upon ejection.

In accordance with one of several important aspects of the present invention, each carrier includes a conveyor pan that supports the ej ector flap and defines the support ledge for the coded article. In the preferred embodiment, each pan is L-shaped and mounted at an acute angle to the horizontal plane. This angled placement is effective to prevent the article from tipping forward or falling from the pan as the carrier is driven around the carousel. The specific angle formed depends upon the particular application and specifications of the sortation system, and can be between 10° and 80° to the horizontal plane.

Also in the preferred embodiment, the ejector flap is hinged to the upper end of the conveyor pan and freely pivots outwardly when actuated to push the article from the support ledge. The leading and trailing edges of the ejector flap are outwardly divergent; that is, they project angularly outwardly relative to each other, and thus define a cradle for the article resting on the support ledge. A pusher arm carrying a cam follower is secured to the back of the ejector flap and extends through an opening in the rear of the conveyor pan.

At each distribution station, a gate is provided for engaging the cam follower carried by the pusher arm. The gate is selectively movable between an open and closed position in response to a signal received from the controller. Thus, when the carrier supporting an article or package having a selected parameter approaches the distribution station corresponding to that parameter, the controller signals the gate to move to the open position. The camming action provided by the open gate actuates the pusher arm to a forward position, which in turn forces the hinged ejector flap to sweep across the ledge. In this fashion, the article is positively ejected at the selected distribution station. The cam follower preferably then remains engaged as the carrier travels forward and clears the gate. The ejector flap thus remains in the forward, or eject position, around the remainder of the carousel. When the cam follower gets back to the home position on the carousel, the pusher arm and ejector flap are released to their respective stand-by positions. Keeping the cam follower engaged in the forward camming track avoids any inadvertent engagement with open actuator gate(s) associated with any approaching distribution stations. In the preferred embodiment, the pusher arm is mounted to the ejector flap such that it is capable of pivoting in response to a certain predetermined amount of force. Thus, if significant resistance is encountered, such as if the cam follower becomes hung up on the gate or other adjacent structures, the pusher arm may pivot to a release position to prevent any damage from occurring. The pusher arm can then be reset manually to the proper position and normal operation continued.

In accordance with another of the many important aspects of the present invention, the system may be capable of automatically loading articles or packages on the conveyor carriers from a loading station. In one embodiment, the conveyor pans are hinged to the carriers and a means for tilting each pan to a raised, substantially horizontal, position is provided. The trailing edge of the ejector flap includes a plurality of projecting pusher fingers that interleave with the members of a substantially horizontal grate positioned above the frame. An article or package previously placed on the grate manually, or by other loading means, is engaged by the fingers and swept onto the moving ejector pan as the carrier is driven past the grate. The article is gently engaged and drops only a short distance onto the ejector flap of the horizontal conveyor pan. In this way, the deleterious tendency for bouncing, that is characteristic of prior art automated loading arrangements using infeed conveyors, is eliminated. Once the loading station is cleared, the pan is then returned to the lowered position, where the article or package comes to rest on the support ledge. Because of the acute angle to the horizontal plane, and the outwardly divergent leading and trailing edges of the ejector flap, the article is securely cradled. The carrier is then driven past the scanner or other reader, the selected parameter is recognized, and the controller signals the actuator to eject the article or package when the proper distribution station is reached. By employing the automated loading concept as described above, the efficiency of the sortation system is further enhanced without sacrificing the desirable simplistic and reliable overall design.

To fully insure that the article or other package held on the ejector flap is reliably ejected, the flap is preferably provided with a low- friction surface. One preferred manner of creating this low- friction surface is to form outwardly projecting dimples in the upper surface of the flap. As should be appreciated, these dimples keep any substantially flat face on the article or package from establishing full contact with the upper surface of the flap. This reduces any tendency of the article or package to form a vacuum lock with (or otherwise stick to) the article-engaging upper surface of the flap. The tribologically enhanced surface thus provided further insures that full ejection is achieved at the desired instant when the proper distribution station is reached. Instead of outwardly projecting dimples, the use of other low friction coatings or materials is contemplated.

To further insure reliable ejection, the ejector flap may also include a plurality of depending fingers that correspond to slots formed in the support ledge. When the ejector flap is actuated and sweeps across this support ledge, the depending fingers travel through these slots and assist in positively lifting and ejecting the article. As should be appreciated, the depending fingers eliminate any tendency for pinching or catching that would otherwise be created if the lower edge of the flap remained flush with the upper surface of the support ledge. This is especially beneficial where soft or flimsy articles, such as packages of clothing or the like, are presented for sortation. To support the conveyor pan, each carrier includes a wheeled undercarriage that rides along the opposed guide rails forming the guide track. In the preferred embodiment, this undercarriage includes a plurality of vertical casters mounted to permit swiveling in all directions. This swiveling capability advantageously insures that the carriers properly negotiate the curves in the guide track in traversing around the carousel. Additionally, the undercarriage is provided with at least one pair of horizontal bumper wheels. In addition to assisting in guiding the carrier and providing lateral stability, these bumper wheels make only rolling contact with the inside surfaces of the opposed guide rails, which serves to reduce friction and wear.

To keep debris or articles from falling on the guide track, the front face of the support ledge on each conveyor pan may depend downwardly and partially cover the upper surface of the outermost guide rail . Additionally, a flexible web of material may be attached to the trailing and leading edge of each adjacent pair of carriers. Most preferably, the web is elastic and is attached directly to the leading and trailing edges of a corresponding pair of the adjacent conveyor pans. As should be appreciated, since the web of material is elastic, it stretches and thus does not prevent the conveyor pans from tilting to the uppermost horizontal position during automated loading.

In the preferred embodiment, a cable drive system is employed to drive the series of carriers around the carousel. Specifically, each carrier is connected directly in series to a continuous cable pulled around the carousel. A drive sprocket positioned adjacent to one curved end of the frame and an idler sprocket at the opposite curved end is effective in driving and guiding the cable. The use of a cable arrangement is particularly preferred, since it insures that the carriers remain properly spaced and the timing of the article ejection is precise. Despite the description of a cable drive arrangement as being preferred, it should be appreciated that the use of other types of arrangements for driving the carriers are possible.

A further aspect of the invention, and in accordance with its objects and purposes, is to provide a method of sorting coded articles or packages according to a selected parameter and separating it for distribution. The method includes the steps of positioning an article on one of a plurality of carriers driven in the endless path around a carousel. The articles are scanned, and then each one in turn, according to sensing a selected parameter, is ejected at its determined distribution station. An ejection flap sweeps across an article support ledge on the carrier to perform the ejection function.

A related method for automatically loading articles or packages in a sortation system or the like is also disclosed. This method includes the step of lifting a conveyor pan on an article carrier to a horizontal position. In this position, projecting fingers carried by the pan interleave with a grate holding at least one article. The fingers sweep the article onto the pan, which is then lowered to the stand-by position. Ejection is effected when the selected distribution station for that article or package is reached. Still other objects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments, and its several details are capable of modifications in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

Brief Description of the Drawings

The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

Figure 1 is a partially schematic perspective view of the overall sortation system of the preferred embodiment of the present invention, including a partially cutaway view of an automated loading station; Figure 2 is a side view of the sortation system of the preferred embodiment, where the distribution station includes a sloping chute and the scanner is supported by the frame, spaced from the passing carriers;

Figure 3a is a side view of a single carrier traveling along the guide track supported by the frame; Figure 3b is a rear view of the carrier showing the pivoting pusher arm connected to the rear of the ejector flap through an opening in the conveyor pan, and also illustrating the manner in which the ejector flap is hinged to the conveyor pan, and the conveyor pan is in turn hinged to spaced vertical supports on the undercarriage; Figure 3 c is a cross-sectional top view of the guide track with the upper components on the carrier removed to illustrate the manner in which the horizontal bumper wheels engage the sidewalls of the opposed guide rails along a curve;

Figure 3d is an enlarged cutaway side view of the carrier showing the flap in the forward position ejecting an article from the support ledge at the selected distribution station, which includes a sloping chute;

Figure 4a is an enlarged, partially cutaway top view of the gating arrangement that serves to actuate the ejector flap in a preferred embodiment of the present sortation system; Figure 4b is a top cutaway view of a pair of adjacent carriers, with the cam follower carried by the pusher arm of the leading carrier engaging the gate of the actuator to cause the ejector flap to sweep across the article support ledge;

Figure 5 is a side view of the carrier similar to that of Figure 3a, but showing the manner in which the conveyor pan is tilted to the horizontal position for automated loading; Figure 6a is a partially cutaway perspective view showing a single article carrier with the upper surface of the ejector flap having a plurality of outwardly projecting dimples for creating a low-friction surface to insure that each article is reliably ejected upon actuation of the flap;

Figure 6b is a close-up cutaway and partially cross-sectional view of the dimples shown in Figure 6a taken along line 6a - 6a;

Figure 6c is a cutaway, partially cross-sectional view of the ejector flap illustrating an alternate low-friction surface in the form of a short- pile nylon carpet;

Figure 7 is a cutaway perspective view of a pair of carriers having a flexible web of elastic material extending between the respective conveyor pans to assist in preventing debris from falling onto the guide track; and

Figure 8 is an overall schematic view of a one possible layout of the automated sortation system of the present invention. Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.

Detailed Description of the Preferred Embodiment

With reference to the perspective view of Figure 1, there is shown a preferred embodiment of a sortation system 10 for sorting coded articles A or packages according to a selected parameter. The sortation system 10 includes a plurality of article carriers 12 that ride along a guide track 14. The guide track 14 is defined by opposed S-shaped guide rails 16, 18 held together by a plurality of spaced cross-members 19 (only one shown in Figure 1). As perhaps best understood by viewing Figures 1 and 2 together, the guide track 14 is supported by a frame, generally designated by reference numeral F. The frame F is elongated and is arranged in the form of a carousel R to define an endless path for the article carriers 12, including two elongated sides and two curved ends. Vertically extending legs 20 are provided for supporting the guide track 14 above the ground. As should be appreciated, the length of the sides and the radius of the ends can be adjusted to fit a particular use. Moreover, the shape of the sortation system 10 can also be altered to accommodate any number of turns and to include any number of sides to provide additional sorting capacity.

A plurality of distribution stations DS are located along the sides of the carousel R, as well as at the curved ends, if necessary or desired for a particular sorting operation. As illustrated, each distribution station DS includes a discharge chute, which is preferably passive, such as a flexible chute foimed out of a plurality of interconnected modular links 22 (Figure 2), or a simple U-shaped rigid chute 22a (see Figure 6a). Alternatively, the passive chute may include idler rollers if necessary, or an active chute (not shown) may be utilized, such as one formed of a plurality of driven rollers. Downstream of the chute 22 or 22a, a receptacle (not shown) may be provided for collecting the coded articles having a common parameter that have been scanned and ejected. Instead of receptacles, a takeaway conveyor (not shown) downstream of the chute 22 or 22a, or as an alternative thereto, may be associated with each distribution station DS to transport the articles or packages once ejected to another location for packaging, distribution, or other processing. As illustrated in Figure 2 and shown schematically in Figure 4a, a detector, such as a scanner 24, is positioned in a spaced relationship from the frame F for reading codes on the articles or packages carried by the carriers 12. The scanner 24 is shown supported in a cantilevered fashion by the frame F, but may be mounted on a freestanding support at any position around the carousel R. The scanner 24 is designed to locate and read a parameter on a coded label L attached to each article A as the respective carrier 12 passes. Preferably, the label L is a UPC label and the scanner 24 is one of several known in the art that are capable of rapidly locating and reading a code on a passing article. Upon detecting a selected parameter from each label L on the coded article A, the scanner 24 generates a signal during continuous movement of the carriers 12 around the carousel R. As explained in further detail in the description that follows, based on later processing of the signals generated by the scanner 24 and the known amount of time it takes for each carrier 12 to travel a certain distance around the carousel R (or sensors that evaluate the position of the carriers 12 along the carousel R), each article A having a selected parameter is then ejected on the fly at the corresponding distribution station DS. Instead of providing a stationary scanner 24 as illustrated, it is within the broadest aspects of the present invention to employ a hand-held device that permits manual scanning (not shown).

As shown generally in Figure 2 and in detail in Figures 3a and 3b, each carrier 12 includes a conveyor pan 26 that supports and carries the coded article A as it is transported around the carousel R. In the preferred embodiment, this pan 26 is L-shaped and thus defines a support ledge 28 for each article A. To insure that the article A rests on the ledge 28 as the carrier 12 is driven along the guide track 14, the pan 26 is mounted at an acute angle θ to the horizontal plane H (see Figure 3 a). By positioning the pan 26 at such an angle, the article A fully rests on the support ledge 28 and is prevented from becoming unbalanced and inadvertently tipping forward, which reduces the potential for deleterious jams and/or misdeliveries. In the illustrated embodiment, the angle θ is between approximately 50° to 60°, but may be varied from between 10° and 80° depending upon the particular application, the specifications of the sortation system, and the types of articles presented for sortation. As shown in Figures 3a-3b and described in further detail below, the pan 26 is also hinged to a pair of generally upstanding support members 30 on each carrier 12, and is thus capable of tilting to the horizontal position for automated loading.

Figure 3a also shows in detail the wheeled undercarriage 32 that rides along the opposed guide rails 16, 18 forming the guide track 14 and carries the vertical supports 30 for the pan 26. The undercarriage 32 includes a plurality of vertical casters 34 that are rotatably mounted in brackets 36 having an inverted U-shape. Each bracket 36 is mounted on a shoulder bolt 37 such that it can freely swivel in all directions. This insures that each carrier 12 can smoothly negotiate the curves in the guide track 14 as it is driven around the carousel R. Additionally, to reduce the incidence of friction and wear created as the carrier 12 travels along the guide track 14, as well as to assist in providing lateral stability and guidance, the undercarriage 32 is also provided with one or more pairs of horizontal bumper wheels 38. These bumper wheels 38 are rotatably mounted adjacent to the top of the undercarriage 32 and engage the inside surfaces of the respective opposed guide rails 16, 18 forming the guide track 14 (see action arrows B in Figure 3c). As illustrated in this figure, each shoulder bolt 37 may provide a common mounting for each vertical caster 34 and a corresponding bumper wheel 38.

The undercarriage 32 is also provided with means for connecting each carrier 12 to a continuous drive cable C. It is this drive cable C that serves to pull the carriers 12 along the endless path, as discussed in more detail in the description that follows. The attachment of the cable C to each carrier 12 may be by any known means. For example, as shown in Figures 3a and 5, a projecting tongue 42 having an aperture may be used to support a clamping mechanism 44 secured to a sleeve, coupler or other structure swaged to the continuous cable C. As should be appreciated, the relative spacing of the carriers 12 is determined by the specific location where each clamping mechanism 44 is attached to the cable C. In addition to the support provided by the ledge 28, each article

A is also partially supported by resting on an ejector flap 46 carried on the conveyor pan 26. As best shown in Figures 4b and 6a, the ejector flap 46 in the preferred embodiment is in the form of a tray having a substantially flat middle article-engaging portion and outwardly divergent leading and trailing edges 47a, 47b. These edges 47a, 47b form a cradle for assisting in holding the article A on the carrier 12 by preventing it from tilting or falling from the side edges of the ejector flap 46 during sortation, as well as during automated loading, as explained further in the description that follows.

To permit the flap 46 to pivot forward and eject the coded article A from each carrier 12 when the selected distribution station DS is reached, it is preferably attached to the upper end of the conveyor pan 26 by a pair of hinges 49 (see Figure 3b). This hinged connection allows the flap 46 to freely pivot outwardly when actuated and gently, but reliably, push the article A from the support ledge 28 at the desired instant in response to actuation (see action arrows D, and D₂ in Figure 3a, which shows the ejector flap 46' in the forward position).

In the preferred embodiment, the ejector flap 46 is moved to this forward position 46' by a pusher arm 48. As best shown by viewing Figures 3a and 3b together, the pusher arm 48 is secured to the back of the ejector flap 46 and extends through an opening 50 in the rear of the conveyor pan 26. A cam follower 52 is carried at the inwardly projecting end of the pusher arm 52 that, as described in detail immediately below, when engaged by camming action forces the ejector flap 46 to sweep across the ledge 28 and positively eject any article A or package held thereon.

To actuate the ejector flap 46, a gate 54 is associated with each distribution station DS. As illustrated in Figures 3a and 4a, the gate 54 includes inner and outer pivoting blades 54a, 54b. The inner blade 54a is actively controlled and can be switched between the open and closed positions by a solenoid 55 in response to a signal received from a controller 56 (open position shown at the left of Figure 4a; closed position shown at the right of this figure). The controller 56 continuously receives signals from the scanner 24 regarding the coded information on each article A as it passes. By monitoring the passage of time and the speed of the carriers 12 as they traverse the carousel R (or alternatively by relying on sensors positioned around the carousel R), the controller 56 is able to determine the position of each coded article and signal the inner blade 54a to pivot open to begin the ejection sequence. In the preferred embodiment, the controller 56 is a computer running software that includes appropriate instructions to insure the smooth operation of the system 10 and reliable article ejection at the desired instant in response to the detected parameters on the coded articles. In the open position, the inner blade 54a provides a camming surface for engaging the cam follower 52. A stop 57 associated with each distribution station DS and supported by the inner guide rail 16 and frame (see Figure 3a) serves as a resting point for the non-camming face of the inner pivoting blade 54a in the open position. The outer pivoting blade 54b is passively opened through engagement with the cam follower 52 to allow it to pass to a forward camming track 58, which in the preferred embodiment is partially defined by the vertical outer face of the outer blade 54b at each distribution station DS. To insure that it returns to the home position to form the track 58 once the cam follower 52 passes through the gate 54, the passive outer pivot blade 54b is mounted on a spring loaded hinge 59.

During operation of the sortation system 10, and in accordance with the related method of sorting, when a coded article A having a selected parameter approaches the selected distribution station DS, the gate 54, or more specifically the inner pivoting blade 54a, is moved to the open position by the solenoid 55 in response to a signal received from the controller 56. As should be understood from reviewing the foregoing description, the controller 56 previously received signals from the scanner 24 regarding the selected parameters from the coded label L of each passing article A. The controller 56 then counts the amount of time required for the carrier 12 with an article A having a selected parameter to reach the corresponding distribution station DS and open the corresponding gate 54. When in the open position, the inner pivoting blade 54a is held at an angle such that it abuts the stop 57 (see Figure 4a). The inside camming face of the pivoting blade 54a is engaged by the approaching cam follower 52 (the direction of travel is indicated by action arrow E in Figure 4b). As the cam follower 52 travels along the inner camming face of the angled pivoting blade 54a, it causes the pusher arm 48 to move forward, while simultaneously the opposite surface of the cam follower 52 moves into engagement with the spring-loaded outer blade 54b (see reference numeral 52' in Figures 4a and 4b, as well as action arrows F and G). As a result of the camming action created by the inner blade 54a in the open, pivoted position, the biasing force on the outer blade 54b provided by the spring-loaded hinge 59 is overcome and the cam follower 52 moves into the forward camming track 58 (see reference numeral 52" in Figure 4a).

Upon the cam follower 52 reaching this fully engaged position, the pusher arm 48 is completely moved to the forward position (as designated in dashed line outline in Figure 3a by reference number 48'). This in turn moves the hinged ejector flap 46 to a full forward position 46' such that the article A is positively ejected and falls onto the chute 22 lower end first at the selected distribution station DS (see dashed-line outline of position A' in Figure 3d). As should be appreciated, the gentle slope of the elongated blade 54a when held at an angle in the open position (see Figure 4a) insures that the sweeping is effective to positively eject the article A, but does not impart excessive energy that could prevent the ejected article from landing on the chute 22. The retraction of the inner blade 54a is preferably timed by the controller 56, or a sensor is provided to close it, once the cam follower 52 passes. The gate 54 reopens only when the next carrier 12 having a coded article A with a common parameter arrives. Once ej ection is complete, the cam follower 52 travels along the camming track 58 forward of the gate 54 in position 52" until at least the approaching group, and preferably all of the distribution stations DS around the carousel R are fully cleared. When this occurs, the camming track 58 keeping the cam follower 52 in the forward position ends (see the right side of Figure 4b). The cam follower 52 thus returns to the home position, at which time the ejector flap 26 likewise returns to the retracted or home position. Keeping the cam follower 52 in the track 58 until all the distribution stations DS in the respective distribution zone, or those surrounding the entire carousel R, are cleared prevents it from interfering with the opening of the inner blades 54a of approaching distribution stations. Since the outer pivoting blade 54b of each gate 54 is automatically closed by spring action immediately after the cam follower 52 passes, there is no chance of interference with the cam followers in the forward position 52" as trailing carriers pass. Of course, the location at which the cam follower 52 on each carrier 12 is allowed to return to the home position may depend on several factors, including whether the system 10 includes one or more automated loading stations. Despite the anticipated smooth contact with which the cam follower 52 engages the pivoting blade 54a, the pusher arm 48 is preferably mounted such that it is capable of pivoting about the point of attachment to a release position in response to a certain predetermined amount of resistance. In the preferred embodiment, as shown in Figure 3b, a detent 60 is provided at the interface between the base of the pusher arm 48 and the rear surface of the ejector flap 46. The detent 60 may take any form that provides the desired resistance, such as for example a spring-loaded ball housed in a bore formed in the base of the pusher arm 48 for engaging a corresponding recess (not shown) formed in the rear surface of the ejector pan 46. Regardless of the particular arrangement employed, the detent 60 insures that, if the cam follower 52 becomes hung up on any gate 54 or otherwise encounters significant resistance as the carrier 12 traverses around the carousel R, the pusher arm 48 can move to a release position 48 "(see dashed line outline in Figure 3b). The pusher arm 48 is then simply manually returned to the home position and the sortation operation continues as normal.

To provide the desired easier and/or fully automated loading, and in accordance with the related method, the pans 26 are hinged to the upstanding supports 30 and means for tilting each pan to a substantially horizontal position is provided. In the preferred embodiment, the tilting means includes a second cam follower 62 mounted on a bracket 63 extending from the top rear portion of the conveyor pan 26. In the home position, the cam follower 62 is captured and rides in a continuous C-shaped camming track 64 mounted above the frame F. When tilting is desired, the camming track 64 twists and curves downwardly to a lower vertical position, such that the second cam follower 62 is cammed and the pan 26 moves to a substantially horizontal position (see action arrows H and I, as well as dashed line outline of track 64 and progressive movement of second cam follower to position 62 ' in Figure 5). To avoid creating any interference with the pusher arm 48 as the pan 26 tilts, the gate 54, camming track 58, and other structures are not provided in this section of the system 10.

In the preferred embodiment, the angled trailing edge 47a of each ejector flap 46 is provided with a plurality of projecting fingers 68. Alternatively, the fingers 68 may project from the trailing edge of the conveyor pan 26 itself (not shown). When each pan 26 is tilted to the horizontal position by the camming action, these fingers 68 interleave with a substantially horizontal grate 70 positioned above the frame F, which defines a loading station LS (see Figures 1 and 5). An article A previously placed on the grate 70 either by hand or other loading means, such as a pusher, is engaged and swept onto the cradle-like ejector flap 46 by these projecting fingers 68. The pan 26 is then gradually returned to the home position by twisting and raising the static camming track 64, such that the article A gently comes to rest at an angle on the support ledge 28 and rests flat against the ejector flap 46. During this movement, the outwardly divergent lateral edges 47a, 47b of the ejector flap 46 insure that the article A is fully cradled and prevented from falling from the sides of the carrier 12. If included as part of the overall automated sortation system 10 described above, the carrier 12 then passes the scanner 24 and the selected parameter on the article or package is read, the controller 56 signals the actuator, or gate 54, to open, such that the article A is ejected when the selected distribution station DS is reached.

To insure that loading is reliably completed in a rapid fashion, each loading station LS in the most preferred embodiment includes first and second horizontal grates (not shown), each for loading alternating carriers. Thus, when a leading carrier is sweeping an article from the first grate, the next-in-line carrier is sweeping a second article from the second grate. This alternative arrangement increases the amount of time available for loading each article on the respective grate, and is particularly advantageous when the carriers pass in rapid succession.

Referring now to Figures 6a, 6b, and 6b, insuring that each article A is smoothly and reliably ejected is important in preventing deleterious jams and misdeliveries. To promote this action, the ejector flap 46 can be provided with a low-friction surface. In the preferred manner of providing the desired low-friction surface, and as shown in Figures 6a and 6b, outwardly projecting dimples 72 are formed in the upper surface of the flap 46. These dimples 72 prevent any flat faced or high friction articles from establishing full contact with the upper surface of flap 46. This reduces the area of contact so that there is a lower coefficient of friction, and also eliminates the tendency for forming a vacuum lock. This reduces any tendency of the article or package to stick to the flap 46, and further insures that full ejection is achieved at the desired instant when the selected distribution station DS is reached. As should be appreciated, dimples 72 may also be formed in the chute 22a to provide a low-friction surface for the articles as the transition is made to a downstream location.

Other manners of providing a low- friction surface are possible, such as the use of specialized coatings or attaching sheets or panels of materials having favorable tribological (frictional) characteristics directly to the upper surface of the flap 46. For instance, in certain operations, some or all of the articles presented for sortation may be damp or wet from traveling exposed to the outside environment on the way to the sortation system, such as from a tractor trailer or airplane. To insure that such wet articles are reliably ejected, a short-pile nylon carpet 74 of the type commonly used in outdoor applications can be placed on the upper surface of the flap 46 (see Figure 6c). For semipermanent use, the carpet 74 may be attached to the upper surface of the flap 46 using an adhesive backing, or may be removably attached for intermittent use.

Another optional feature that is quite advantageous in insuring that ej ection is reliably effected is to provide the ej ector flap 46 with a plurality of depending fingers 76. As perhaps best shown in Figure 6a, these fingers 76 are sized and spaced to directly mate with corresponding slots 78 formed in the ledge. Thus, when the ejector flap 46 is actuated and sweeps across the ledge 28, these fingers 76 travel in and sweep through the slots 78. As compared to an embodiment where the lower edge of the flap 46 is flat and simply sweeps across the upper surface of the ledge 28 during ejection, the depending fingers 78 eliminate any tendency for pinching or catching the lower edges of the article A. Thus, when soft or flimsy articles, such as packages of clothing or the like, are regularly presented for sortation, employing this arrangement can be of substantial advantage.

Other optional features may be utilized to keep debris or articles from falling on the guide track 14. One such feature is forming the front face of the ledge 28 on each conveyor pan 12 such that it depends downwardly. In this position, the ledge 28 partially covers the upper surface of the outer guide rail 18 and thus guards against articles or debris inadvertently falling from the pan 26 onto the track 14. A second feature, as illustrated specifically in Figure 7, includes providing a flexible web of material 80 between all or a selected number of adjacent carriers 12a, 12b. Preferably, this web 80 is made of a highly elastic material, such as SPANDEX or the like, and attached directly to the trailing edge of the conveyor pan 26 on a leading carrier to the forward edge of the pan 26. Since the material 80 is elastic, it does not prevent adjacent carriers 12a, 12b from making the turns at the ends of the carousel R, or from tilting to the horizontal position, as occurs during loading. In fact, depending on the relative spacing, the interconnection thus provided by the web 80 may help in tilting the next-in-line carrier 12a to the horizontal position as the forward carrier 12b moves to the horizontal position.

As briefly noted above, the carriers 12 are preferably driven in an endless path around the carousel R by a continuous cable drive system. Specifically, each carrier is attached directly to a continuous cable C. The cable C is then pulled around the carousel R by a horizontal drive sprocket positioned adjacent to one curved end of the carousel R (shown schematically in Figure 8) that engages the portion of the cable exposed between each carrier 12. An idler sprocket at the opposite curved end assists in guiding the cable. Of course, instead of a cable drive arrangement, it should be appreciated that the use of other means to drive the carriers 12 around the carousel R is within the broader aspects of the present invention.

The overall schematic layout of a typical sortation system 10 employing the principles of the present invention, including an automated loading station LS, is shown in Figure 8. A plurality of distribution stations DS are provided along the straight sections of the carousel R in two "drop zones." The scan zone can be provided just before the first scan zone (see bottom of Figure 8). The drive for the carriers is provided at a first curved end of the carousel R (see right-hand end) and the idler is provided at the opposite curved end. After being engaged at the respective distribution station DS by the corresponding gate, each cam follower returns to the home position once the second distribution zone is fully passed. Automated loading is completed by a loading station LS positioned at the end of the second drop zone. In summary, a novel sortation system 10 and related method are provided for the improved sorting of coded articles, packages, or the like. The system 10 includes a plurality of carriers 12 driven in an endless path around a carousel R (see Figures 1 and 2). A coded article A resting on the carrier 12 passes a detector, such as a scanner 24. Coded information is read by the scanner 24, which sends a signal to a controller 56 that determines the proper distribution station DS for ejection of the article according to a selected parameter of the coded information. When the coded article A having the selected parameter reaches the desired distribution station, the controller 56 signals an actuator, such as at the gate 54, which engages a cam follower 52 supported by a pusher arm 48 on the carrier 12. The cam follower 52 in turn causes an ejector flap 46 to sweep across a support ledge 28 and positively and reliably eject the article A at the desired instant (see Figure 3d). To facilitate the automated loading coded articles, each carrier 12 may also include a conveyor pan 26 that is capable of tilting to a substantially horizontal position (see Figure 5). In this position, projecting fingers 68 adjacent to the trailing edge of the pan 26 interleave with a grate 70 and sweep a coded article onto the pan for later sortation and distribution. Since the article A falls only a short distance from the grate 70, the deleterious bouncing that is characteristic of prior art automated loading arrangements employing simple infeed conveyors is eliminated. The pan 26 is then returned to the home position and the article A held thereon ejected at the selected distribution station, if desired. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.

Claims

Tn the Claims

1. A system for sorting coded articles, packages or the like according to a selected parameter for distribution, comprising: a plurality of carriers, each having a ledge for supporting at least one coded article adjacent to an ejector flap; a frame defining a carousel and including a track for guiding said carriers in an endless path; a driver to impart motion to said carriers; a plurality of distribution stations located around said carousel; a detector for detecting a selected parameter on each coded article; an actuator for causing said ejector flap to sweep across said ledge and eject each article as coded at a selected distribution station; a controller for signaling the actuator to eject the article at the selected distribution station in response to the detection of a selected parameter by said detector; whereby said carriers are operative to move the coded articles in an efficient fashion and insure reliable ejection of the coded articles at the selected distribution station so as to optimize the operation of the sortation system.

2. The sortation system of Claim 1, wherein each conveyor carrier includes a pusher arm having a cam follower; and said actuator includes a gate associated with each of said distribution stations that is selectively movable between an open and closed position in response to a signal received from said controller, whereby said cam follower is engaged by said gate in the open position and forces said ejector flap to sweep across said ledge and eject the article at the selected distribution station.

3. The sortation system of Claim 2, wherein a conveyor pan supported by each said carrier defines said article support ledge.

4. The sortation system according to Claim 3, wherein said pusher arm is attached directly to said ejector flap through an opening in the rear of each said conveyor pan.

5. The sortation system of Claim 4, wherein said pusher arm is capable of pivoting about the attachment point and a detent is provided at the interface between said pusher arm and the ejector flap, whereby said detent allows said pusher arm to pivot to a release position if significant resistance is encountered.

6. The sortation system of Claim 3, wherein the ejector flap is hinged to an upper end of said conveyor pan.

7. The sortation system of Claim 3, wherein said conveyor pan is held at an acute angle to the horizontal plane in a home position such that any article carried thereon also rests on said ejector flap.

8. The sortation system of Claim 7, wherein said conveyor pan is held at an acute angle to the horizontal plane in a home position, but is capable of tilting to a substantially horizontal position for loading.

9. The sortation system of Claim 8, further including means for titling said conveyor pan to the substantially horizontal position.

10. The sortation system of Claim 9, wherein a plurality of fingers project from adjacent a trailing edge of said conveyor pan.

11. The sortation system of Claim 10, further including a grate positioned above said carousel for holding at least one article for distribution, said projecting fingers interleaving with said grate when said pan is in the horizontal loading position to sweep the article onto said conveyor pan.

12. The sortation system of Claim 11 , further including means for returning said conveyor pan to the home position such that the article held thereon is ready for ejection at one of said selected distribution stations.

13. The sortation system of Claim 1 , wherein the ej ector flap is provided with a low-friction upper surface that insures smooth ejection of the article in response to the actuation of said ejector flap.

14. The sortation system of Claim 13, wherein said low- friction surface is provided by a plurality of outwardly projecting dimples on said ejector flap.

15. The sortation system of Claim 1 , wherein said ej ector flap includes a plurality of downwardly projecting fingers that interleave with corresponding slots formed in said support ledge, whereby upon sweeping across said slots in said ledge, positive ejection function is reliably provided.

16. The sortation system of Claim 1, wherein said support ledge includes a depending front vertical face that assists in preventing debris from falling on said guide track.

17. The sortation system of Claim 1 , further including a web of flexible material extending between each pair of carriers to assist in preventing debris from falling on said guide track for said carriers.

18. The sortation system of Claim 1, wherein each of said carriers support a plurality of vertical casters that ride along said guide track.

19. The sortation system of Claim 18, wherein each of said casters is mounted in a bracket that is secured to said carrier by a shoulder bolt, whereby said shoulder bolt permits said casters to swivel to assist each of said carriers in traversing around the curves in said guide track.

20. The sortation system of Claim 18, wherein each of said carriers further includes at least one pair of horizontally extending bumper wheels for engaging the sidewalls of said guide track, whereby said bumper rollers provide lateral stability to said carrier and reduce friction and wear by creating only rolling contact with the sidewalls of said guide track.

21. The sortation system of Claim 1, wherein said detector includes a scanner for reading the selected parameter during movement of the coded articles as said plurality of carriers are driven around said carousel.

22. The sortation system of Claim 1 , wherein each distribution station includes a chute for carrying the at least one coded article ejected from said carrier to a downstream location.

23. The sortation system of Claim 1 , wherein said ej ector flap includes outwardly divergent leading and trailing edges to form a cradle for assisting in supporting said article on said carrier.

24. In a sortation system, a station for automatically loading at least one article, package or the like onto one of a plurality of carriers, comprising: each carrier having a conveyor pan that is capable of titling from a home position to a substantially horizontal position for loading, said carrier supporting a plurality of projecting fingers; at least one loading station including a substantially horizontal grate for supporting least one coded article; means for tilting each said conveyor pan to the substantially horizontal position such that said projecting fingers interleave with said grate as said carrier passes thereby, said fingers sweeping said at least one article onto said conveyor pan; means for returning each conveyor pan to the home position, whereby efficient and effective automated loading of said at least one article on each said carrier is provided.

25. The loading station in a sortation system according to Claim 24, wherein said conveyor pan supports an ejector flap and said fingers project from a trailing edge of said flap.

26. A method for sorting coded articles, packages or the like according to a selected parameter, comprising: positioning at least one coded article on one of a plurality of carriers driven around an endless path carousel; driving the carriers around the carousel to present each coded article held thereon in turn to a scanning station; providing a plurality of distribution stations around said carousel; scanning each article as coded to determine said selected parameter; and actuating an ejector flap on each said carrier to positively eject the article having the selected parameter at the corresponding distribution station; whereby said carriers are operative to move and eject the coded articles in an efficient and effective manner so as to optimize the operation of the sortation system.

27. The method for sorting of Claim 26, further including providing a loading station including a substantially horizontal grate for holding at least one article for later distribution, providing a trailing edge of said ejector flap with a plurality of projecting fingers, and tilting each ejector flap to the horizontal position such that said fingers interleave with said grate and sweep the article held thereon onto said flap.

28. A method of automatically loading an article, package, or the like on a carrier driven along a sortation system or the like, comprising: placing an article on a loading station including a substantially horizontal grate for supporting the article; tilting a conveyor pan on the carrier having a plurality of upwardly projecting fingers from a home position to a substantially horizontal position; and driving said carrier past the loading station such that said fingers interleave with said grate and sweep said article onto said pan.

29. The method according to Claim 28, further including returning said conveyor pan to the home position once said article is loaded thereon.

30. The method according to Claim 29, further including ejecting the article from said conveyor pan once said article is returned to the home position.