Abstract:
A package sorting conveyor system. The conveyor system includes: a conveying track; at least one unloading station; and a transition zone funnel upstream of the unloading station to receive the package from the conveying track, the transition zone funnel including a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position. Also, in the preferred embodiment, the present invention includes a secondary downstream chute located downstream from the transition zone funnel for conveying the discharged package to its final destination.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates generally to package sorting conveyors and, more particularly, to a conveyor system having a conveying track, a transition zone funnel for receiving a package from the conveying track, selectively positionable between at least a first and second position, and a secondary chute downstream from the transition zone funnel having at least two definable discharge paths. 
     (2) Description of the Prior Art 
     Conveyor systems having a number of individual carrying carts have been used for many years to carry and sort packages such as shoes and apparel or other items such as mail. Conventional tilt tray sorters discharge their goods onto individual chutes located near each packer. For example, U.S. Pat. No. 5,054,601 to Sjogren et al. discloses a package sorting conveyor comprised of a train of tilt tray carriers coupled in tandem to form a continuous loop. Each carrier includes a pivotally mounted tilt tray normally maintained in an upright position. The carriers are moved around the loop by a series of motors spaced around the loop. Branching out from the loop are out-feed positions for receiving packages from the carriers. When a particular carrier holding a particular package to be sorted reaches a selected out-feed position, an actuator tilts the tray to dump the package into a transition zone funnel or other package-receiving device. 
     Another example of a similar package sorting conveyor is disclosed in International PCT Application No. PCT/DK90/00047 of Kosan Crisplant A/S. 
     One significant disadvantage of most conventionally designed package sorting conveyors is that the conveyor carriers laterally tilts only on a horizontal axis parallel to the direction of conveyor travel. While this accomplishes the objective of dumping the package from the carrier at the out-feed position, the package is often roughly tumbled or rolled, sometimes damaging the package and package&#39;s contents. One reason for this is that the package typically is unloaded from the carrier while still traveling forward at the same speed as the conveyor. Thus, packages tend to slam into a forward retaining wall of the transition zone funnel or other package-receiving device. 
     Another problem with most conventional horizontally tilting conveyors is that because the package is moving forward at full speed when they are unloaded at the out-feed position, the transition zone funnel must be relatively wide so that the package does not miss the funnel and fall off the conveyor past the funnel. This often unnecessarily decreases the number and location of the out-feed positions of the conveyor system. 
     U.S. Pat. Nos. 4,744,454 and 5,086,905, both to Pölling, disclose previous attempts to remedy this problem of rough handling by conventional laterally tilting conveyor carriers. Both of these patents to Polling disclose a conveyor element for a package conveyor that includes a tilting carrier tray mounted to be rotatable about two swivel axis. A first swivel shaft extends obliquely downward from the under side of the carrying tray and is in turn connected at an angle to the end of a second swivel shaft extending obliquely upwards from a base support part of the conveyor element. Together, the two swivel shafts form a “V” that points in the direction of the conveyor travel. Both of the swivel shafts lie in the vertical plain of symmetry of the conveyor element when the carrier tray is disposed in its upright position. 
     Because the carrier tray of Polling rotates about two oblique axis, the carrier tray tilts not only on a horizontal axis, but is moved through a geometrically complex spatial reorientation during package discharge. This allows for more gentle placement of a package on an out-feed chute than can be accomplished using conventional conveyor trays that laterally tip only on a horizontal axis because the Polling conveyor element imparts some degree of rearward velocity to the package as it is discharged, which, when added to the forward velocity of the conveyor system, results in the package&#39;s forward velocity during discharge being lessened. 
     However, the conveyor elements of both of Pölling&#39;s patents are unduly complicated. In fact, the second Pölling patent was directed towards simplifying the original design disclosed in the first Pölling patent which was expensive and complicated to manufacture efficiently. As a result of this complexity and cost, the Pölling devices have not enjoyed significant commercial acceptance and success. In addition, there is no provision in Pölling to take advantage of the tilting movement of the tray to allow the direction of the discharged package to be further controlled. 
     Another significant disadvantages of conventionally designed package sorting conveyors is the lack of versatility and amount of floor space required by the conveyor, especially when sorting a variety of items on the same conveyor is desired. For example, it is common in distribution centers to sort items both contained in cardboard boxes, such as shoes, and in polyurethane bags, such as shirts. 
     Conventional sorting conveyors sort boxes and bags by providing package-receiving devices at out-feed positions that have a roller-lined surfaces for boxes, and more steeply declined package-receiving devices at different out-feed positions without rollers for bags. Thus a fixed number of box out-feed positions and bag out-feed positions are established on the conveyor. Alternatively, distribution centers may use two conventional sorting conveyors, one dedicated to boxes and one to bags. 
     It is often the case, however, that when sales product mixes change, a distribution center sorting both boxes and bags is required to sort either fewer boxes and more bags, or vice versa. In such cases, a distribution center using a sorting conveyor with a fixed number of out-feed positions for boxes and bags must make costly modifications to a conventionally designed sorting conveyor. In the alternative, the center may have designed excess out-feed positions for both boxes and bags into the conventional sorting conveyor in anticipation of product mix changes, which increases the size of the conventionally designed sorting conveyor. So the distribution center must choose between such competing alternatives. 
     Thus, there remains a need for a new and improved package sorting conveyor system having a conveying track and a transition zone funnel for receiving a package from the conveying track which is selectively positionable between at least a first and second position while, at the same time, includes a secondary chute downstream from the transition zone funnel having at least two definable discharge paths. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a package sorting conveyor system including: a conveying track; at least one unloading station; and a transition zone funnel upstream of the unloading station to receive the package from the conveying track, the transition zone funnel including a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position. Also, in the preferred embodiment, the present invention includes a secondary downstream chute located downstream from the transition zone funnel for conveying the discharged package to its final destination. 
     In the preferred embodiment, the transition zone funnel includes: (i) an inlet adjacent to the conveying track at the unloading station for receiving the package; (ii) an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; (iii) an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and (iv) a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis. 
     Also, in the preferred embodiment, the inlet of the transition zone funnel is substantially flat to receive the package being discharged by the package sorting conveyor system. Also, the inlet may be wider than the front edge of the package providing a wider range of curvature enabling the package to slide off the package sorting conveyor system onto the inlet. The upwardly inclined downstream wall preferably has a radius of curvature of between about 6 inches and 2½ feet, with about 1 foot being most preferred. Thus, the forward direction of the package may change about 90° from its initial direction on the conveying track to its direction at the outlet of the funnel. In the preferred embodiment, the surface of the transition zone funnel is a low-friction, wear-resistant polymeric material, such as high-density polyethylene. The positioner assembly for selectively positioning between at least a first and a second position along at least two axis may further include at least one pivot point and a drive means. The pivot point may be a ball joint, an inclined axis or at least two independent pivots. In the preferred embodiment, the two independent pivots include a rotary joint and a hinge joint. The drive means for positioning may include a rotary actuator and a linear actuator. In the preferred embodiment, the linear actuator is a fluid actuator, such as a pneumatic air cylinder. 
     The transition zone funnel may further include a powered conveying section for accelerating or decelerating the package. The powered conveying section may be a powered roller or a powered belt. 
     The secondary chute may further include at least two definable discharge paths. In the preferred embodiment, at least one of the discharge path includes at least one path having a curved surface. In the preferred embodiment, the curved surface is between about 90° and 360°. Also, in the preferred embodiment, the curved surface is between about 6 inches and 30 inches radius of curvature. The surface of the secondary downstream chute may be a low friction, wear resistant polymeric material. In the preferred embodiment, the material is a high density polyethylene. 
     Accordingly, one aspect of the present invention is to provide a package sorting conveyor system including: a conveying track; at least one unloading station; and a transition zone funnel upstream of the unloading station to receive the package, the transition zone funnel including a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position. 
     Another aspect of the present invention is to provide a transition zone funnel for receiving a package discharged at an unloading station by a package sorting conveyor system having a conveying track, the transition zone funnel including: an inlet adjacent to the conveying track at the unloading station for receiving the package; an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis. 
     Still another aspect of the present invention is to provide a package sorting conveyor system including: a conveying track; at least one unloading station; a transition zone funnel upstream of the unloading station to receive the package from the conveying track, the transition zone funnel including: (i) an inlet adjacent to the conveying track at the unloading station for receiving the package; (ii) an upwardly inclined downstream wall located downstream of the inlet for preventing the package from tipping over; (iii) an outlet located downstream from the upwardly inclined downstream wall for discharging the package from the funnel; and (iv) a positioner assembly for selectively positioning the outlet of the transition zone funnel between at least a first and a second position along at least two axis; and a secondary downstream chute located downstream from the transition zone funnel for conveying the discharged package to its final destination. 
    
    
     These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram illustrating a package sorting conveyor constructed according to the present invention; 
     FIG. 2 is a front, elevation view of a single tilting conveyor cart of the package sorting conveyor and the power source of the conveyor; 
     FIG. 3 is a sectional side view of a tilting conveyor cart, taken along lines  3 — 3  of FIG. 2, which shows the tiltable support apparatus and the angled pivot structure of the tilting conveyor cart; 
     FIG. 4A is a top view of a train of carts of the package sorting conveyor; 
     FIG. 4B shows the train of carts of FIG. 4A with one of the carts in its tilted position and unloading a package onto the transition zone funnel; 
     FIG. 5 is a perspective view from the bottom of the four secondary downstream chutes of the tilt tray conveyors and transition zone funnel, and secondary downstream chute shown in FIG. 1; 
     FIG. 6 is a side view of the transition zone funnel for the four secondary downstream chutes; 
     FIG. 7 is an end view of the bottom of the four secondary downstream chutes; 
     FIG. 8 is a side view of the transition zone funnel; 
     FIG. 9 is a bottom perspective view of the positioner assembly for the transition zone funnel; 
     FIG. 10 is a bottom rear view of the positioner assembly for the transition zone funnel; 
     FIG. 11 is an enlarged top view of the transition zone funnel illustrating an alternative embodiment having a powered conveying surface. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as “forward,” “rearward,” “left,” “right,” “upwardly,” “downwardly,” and the like are words of convenience and are not to be construed as limiting terms. 
     Referring now to the drawings in general and FIG. 1 in particular, it will be understood that the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto. As best seen in FIG. 1, a sorting conveyor, generally designated  10 , is shown constructed according to the present invention for transporting and sorting a package  11  or other object. The sorting conveyor  10  includes a train of individual carts  20 , connected end to end, which preferably form an endless loop around a closed conveyor track  12 . 
     As best shown in FIG. 2, each cart  20  includes three major sub-assemblies: a trailer frame structure  22 , a generally horizontally disposed carrying tray  40  for holding the package  11  and a tiltable support apparatus  50 . 
     Each cart  20  is built around a base trailer frame structure  22  to which other components of each cart  20  are mounted. Mounted atop the trailer frame structure  22  of each conveyor cart  20  is the tiltable support apparatus  50 , which supports the carrying tray  40  thereabove. The tiltable support  50  supports the carrying tray  40  above the trailer frame structure  22  and allows tilting of the carrying tray  40  toward either side of the sorting conveyor  10  to unload a package into one of the unloading stations. Further details and operation of the two-axis tilt tray are set forth in the parent application, the entire disclosure of which is hereby incorporated by reference. 
     As best seen in FIG. 3, the tiltable support apparatus  50  generally includes three components: an upper support structure  52  joined to a bottom surface of the carrying tray  40 , a lower support structure  58  centrally mounted atop the longitudinal base member  24 , and an angled pivot structure  60  pivotally connecting the lower support structure  58  to the upper support structure  52  along a pivot axis  62 . 
     In turn, the upper support structure  52  includes a front support member  54  and a back support member  56 . The lower support structure  58  is preferably, generally plainer, lying in the vertical plain parallel to the conveyor line of travel  64 , and includes an angled upper edge  58 A. The pivot structure  60  preferably includes an axle  68  that runs either through or along the upper edge  58 A of the lower support structure  58  and is connected to the front and back support members  56 ,  58  respectively. Preferably, the axle runs through lower regions of the front and back support members  56 ,  58 . 
     As can be seen, the front support member  54  depends further down from the carrying tray  40  then the back support member  56 . While the lower support  58  is rigidly fixed to the trailer frame  22 , the axle  68  allows the upper support structure  52  to pivot along the pivot axis  62  of the pivot structure  60 . 
     In an alternate embodiment of the tiltable support apparatus [not shown], the upper support structure  52  could also include, similar to the lower support structure  58 , a generally plainer member that lies in the vertical plain parallel to the conveyor line of travel  64 . In this case, the angled pivot structure  60  could take on the form of a hinge structure joined together the two generally plainer support structures  52 ,  58 . 
     The pivot axis  62  lies in a vertical plain parallel to the conveyor line of travel, which is shown in the drawings as horizontal line  64 . However, unlike conventional sorter conveyor tilting carts, the pivot axis  62  of the conveyor cart  20  of the invention is disposed at an angle θ to the conveyor line of travel  64  so as to impart two axial components to the tilting of the carrying tray  40 . Preferably, the pivot axis  62  angles downwardly at an angle of approximately 20-45 degrees below horizontal in a forward direction. In the embodiment disclosed, the pivot axis  62  is angled downwardly 30 degrees. The pivot axis  62  preferably intersects a plain occupied by the carrying tray  40  rearward of the center of the tray  40 . 
     By disposing the pivot axis  62  in a downwardly directed angle θ instead of parallel to the conveyor line of travel  64 , two axial components are imparted to the tilting motion of the carrying tray  40 . The first axial component of the trays&#39; tilting motion is lateral tipping on a horizontal axis parallel to the conveyor line of travel  64 . The second axial component of the trays tilting motion is rotating around a vertical axis  66  perpendicular to the conveyor line of travel. Thus, while the tray only tilts along a single, angled pivot axis  62 , the overall motion of the tray  40  as it tilts includes two axial components. 
     FIG. 4A shows a top view of a train of carts of the package sorting conveyor in their un-tilted position. One affect of the two-axis tilting of the carrying tray  40  is that a side  44   b  of the tray that is tilted downwardly also rotates rearwardly relative to the cart  20 , as shown in FIG. 4B by line  46   a . Side  44   d  of the tray, which is tilted upwardly, rotates forwardly relative to the cart  20 , as shown by line  46   b . In the preferred embodiment in which the pivot axis  62  intersects the plain occupied by the tray  40  rear of center, the front side  44   a  of the tray  40  rotates a greater distance around the vertical axis  66 , then the backside  44   c  of the tray  40 , upon tilting of the tray  40 . 
     As also shown in FIG. 4B, the bisecting center line of the tray  40  rotates further at its forward end from the horizontal line of travel  64 , then at its rearward end. Thus, front side rotation line  48   a  follows a longer arch than backside rotation line  48   b . By rearwardly rotating whichever side of the tray  40  is being tilted downwardly, some rearward velocity is imparted to package  11  as they are being discharged from the cart  20  of the invention into the transition zone funnel  14 . Thus, package  11  is discharged at a lower velocity relative to the transition zone funnel  14  than the velocity of the train of conveyor carts as a whole. This enables the package  11  to be discharged into a narrower “chute” than could be accomplished using a conventional conveyor cart. Additionally, because the package is slowed down somewhat as it is discharged, there is less potential for damage to occur. 
     FIG. 5 is a perspective view from the bottom of four secondary downstream chutes  138  looking up at the conveyor track  12 . At the top of the four secondary downstream chutes  138  is the transition zone funnel  110 . The inlet  114  of the transition zone funnel  110  is the side of the funnel  110  closest to the conveyor track  12 , where packages enter the funnel  110 . The funnel  110  also includes an upwardly inclined downstream wall  116  for guiding packages into the funnel  110 . Four secondary chutes, each having low-friction curved surface  148  are downstream from the transition zone funnel  110 . 
     FIG. 6 is a side view of the transition zone funnel  110  and the four secondary downstream chutes  138 . The positioner assembly  120  selectively moves the transition zone funnel outlet  118  into alignment with one of the four secondary downstream chutes  138 . 
     FIG. 7 is an end view of the bottom of the four secondary downstream chutes  128 , each having a low-friction curved surface  148 . A pair of chutes rests directly atop and runs along parallel to a pair underneath. At the top of FIG. 9 is the position zone funnel  11 , including the inlet  114 , outlet  118 , and upwardly inclined downstream wall  116 . 
     FIG. 8 is a side view of the transition zone funnel  110  including the positioner assembly  120 , which includes a rotary joint  126  and horizontal drive means  125  for moving the transition zone funnel  110  about a vertical axis and a hinge joint  130  and vertical drive means  124  for moving the funnel  110  about a horizontal axis. 
     FIG. 9 is bottom perspective view of the positioner assembly  120  including a lower plate  111  and an upper plate  112 . Also shown is the horizontal drive means  125  and rotary joint  136  and a vertical drive means  124  for moving the transition zone funnel  110  about a horizontal axis. 
     FIG. 10 is a rear bottom view of the positioner assembly  120  including the upper  112  and lower plate  111  of the transition zone funnel  110 . A vertical drive means  124  for moving the transition zone funnel  110  about a horizontal axis, and a horizontal drive means  124  for moving the transition zone funnel  110  about a vertical axis is also shown. 
     FIG. 11 is an enlarged top view of the transition zone funnel  110  illustrating an alternative embodiment having a powered conveying surface  132  for moving a package from the funnel  110  inlet along the conveying surface  132  to the funnel outlet  118  and selectively discharging the package onto the low-friction curved surface  148  of one of the four secondary downstream chutes  138 . 
     In operation, a package moves along the conveyor track  12  to an out-feed position where it is discharged into the inlet  114  of the transition zone funnel  110 , with the upwardly inclined downstream wall  116  slowing the forward momentum of the package and guiding the package across the funnel  110  into the funnel outlet  118 . When a box package moves across the funnel  110 , the funnel  110  orients the package such that an end of the package is generally perpendicular to the conveyor track  12  when the box leaves the funnel outlet  118 . In the preferred embodiment, gravity moves the package along the transition zone funnel  110  from the inlet  114  to the outlet  118  because the funnel inlet  114  is higher than the funnel outlet  118 . Also, the transition zone funnel  110  includes a low-friction surface to reduce the coefficient of friction between the package and the funnel surface. In an alternative embodiment, the transition zone funnel includes a powered conveying surface  132  for moving a package across the transition zone funnel  110 . 
     The positioner assembly  120  selectively moves the transition zone funnel  110  so that its outlet  118  is aligned with one of four output positions. The positioner assembly  120  includes a vertical drive means  124  and a hinge joint  130 , pivotally connecting the transition zone funnel  110  to the conveyor track  12  along a lower plate  111  of the transition zone funnel. When the vertical drive means  124  is selectively activated, the drive means  124  exerts a force upon the bottom of the transition zone funnel  110  in an upward direction, rotating the funnel  110  from a lower to an upper position about the hinge joint  130  that connects the funnel lower plate  111  to the conveyor track  12 . The funnel  110  moves by the force of gravity from the upper to lower position. 
     The transition zone funnel  110  also includes a rotary joint  126  for connecting the lower plate  111  of the transition zone funnel  110  to an upper plate  112  of the funnel  110 . The upper plate  112  is rotated about the rotary joint  126  with a horizontal drive means  125 , which selectively operates in opposite directions to move the upper plate  112  of the funnel  110  between a right and left position. In the preferred embodiment, the vertical drive means  124  and horizontal drive means  125  of the positioner assembly drive simultaneously, as required, to selectively move the funnel  110  between four output positions such that the funnel outlet  118  deposits a package into one of the four secondary downstream chutes. 
     The four secondary downstream chutes  138  are aligned at the end of the conveyor. One pair of chutes rests atop and parallel to another pair below. Each of the four secondary downstream chutes  138  has a low-friction curved surface  148 . In the preferred embodiment, gravity moves packages along the chutes, which  138  decline about 15 degrees from the funnel outlet  110  to a position above a floor where an operator removes the packages from the chutes  138 . 
     Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, the four secondary downstream chutes can be formed of several sections of flat sheet metal or other materials instead of being a continuously curved surface. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.