Abstract:
An automated conveyor sortation and item discharge system for sorting items of varying sizes and weights to designated output destinations along a conveyor. The system utilizes a segmented slat conveyor connected by flexible connectors. The flexible connectors form a tooth for driving the conveyor by a sprocket. The flexible connectors isolate adjacent slats, and the flexible teeth isolate the slat conveyor from the drive sprocket for a enhanced reduction in noise levels. The system may utilize a conventional belt conveyor or rigid platforms attached by flexible connectors. Removable ejection mechanisms can be attached to the individual slats of the slat conveyor or to the belt of a belt conveyor. The ejection mechanisms have self-contained drive and actuation mechanisms and may operate independently of the speed of the conveyor. The drive mechanism for the ejection mechanism may be located separately from the ejection mechanism to drive the ejection mechanism when the ejection mechanism moves adjacent to a desired discharge destination. A programmable controller may be provided to control the conveyor and the discharge of items from the conveyor by the ejection mechanisms. The system is easy to repair and operates at high speeds at reduced noise levels.

Description:
RELATED APPLICATIONS 
     The present application is a continuation of and claims the full benefit to and priority of prior pending application Ser. No. 09/345,545, filed Jun. 30, 1999 is now U.S. Pat. No. 6,548,602 which itself is a divisional of application Ser. No. 08/786,247, filed Jan. 22, 1997, now issued as U.S. Pat. No. 5,921,378. Therefore, the present application has an effective filing date of Jan. 22, 1997. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to automated sorting of items such as packages to a variety of output destinations, and more particularly relates to a system utilizing parcel ejection mechanisms to discharge items from a slat or belt conveyor onto designated output chutes, bins or subsequent conveyors under programmed or manual control. 
     BACKGROUND OF THE INVENTION 
     In modern high volume package delivery systems, a variety of material handling systems are often used. Such material handling systems often include package conveying systems that divert packages placed thereon to a variety of output destinations such as chutes, bins, and subsequent conveyor systems. Systems for diverting objects from a moving conveyor have been available for many years. Such systems are useful in discharging objects from a conveying surface at selected stations located along the path of the conveying surface. 
     Typical package diverting systems utilize a pusher element mounted relative to a conveying surface which when actuated ejects an adjacently placed package laterally across the conveyor surface to the desired discharge station. Many such systems guide the pusher element laterally across the conveying surface using a complex series of guide tracks or cams mounted beneath the conveying surface. Such systems are noisy and relatively difficult to repair. Additionally, the speed with which such systems eject parcels from the conveying surface is typically related to and restricted by the speed of the conveying surface. 
     The amount of “down time” a conveying system or sorting system is shut down for repairs and/or maintenance significantly impacts operating efficiency. Thus, reliability and ease of repair are major requirements. Reliability can be increased and down time reduced by constructing package conveying and sorting systems where mechanical assemblies may be quickly and easily removed and replaced without the use of tools. Such construction may be accomplished by use of detachable mechanical assemblies such as package diverters or by mounting mechanical assemblies on modular conveying systems such that the failed mechanical assemblies or the conveyor sections housing the failed assemblies may be quickly removed and replaced. Furthermore, because of the increased speeds required of modern package handling systems, reduction of noise levels is also a major requirement. 
     In U.S. Pat. No. 4,170,281 to Lapeyre, a modular conveyor belt is provided from extruded flexible links which may be either plastic or metal having ends joinable into an endless belt by an extruded substantially rigid joining member. 
     In U.S. Pat. No. 3,349,893 to Jordan, a segmented conveyor belt is disclosed having rigid plate sections that are joined together by flexible arch joining members. The joining members include marginal beads that are inserted into retainer grooves formed into the plates transverse to the direction of travel of the conveyor belt. Adjoining members are made of elastic, flexible materials such as rubber. 
     The modular diverter shoe and slat construction disclosed in U.S. Pat. No. 5,127,510 to Cotter describes a modular diverter shoe for use in a slat conveyor. A diverter shoe is mounted to each slat so that the shoe may glide across the slat. The movement of the diverter shoe is affected by a guide pin and coaxial bearing which engages a network of guide tracks located beneath the conveying surface. When a package is to be diverted, a diverting switch is actuated to switch the guide pins for the diverter shoe adjacent to the package onto a diagonal track, which causes the diverter shoe to move across the slat and eject the package. 
     Another apparatus for sorting objects is disclosed in U.S. Pat. No. 4,732,260 to Canziani. In that system, a conveyor belt is described in which each conveyor element has a slit. The pusher elements are slidably inserted into the slits and each pusher element is connected to a drive element that extends beneath the conveyor surface. The drive element is attached to rollers and interacts with a series of cams or guide rails located beneath the conveyor. The cams include an electro-pneumatic two-position end portion. In one position, the cam engages the drive element rollers and slides the pusher element. In a second position, the rollers do not engage the guide rails. 
     In some of the systems noted above, pusher elements are guided across an underlying conveying surface by interacting with a series of cams, guide rails or guide tracks located beneath the conveyor surface. It would appear that the action of the components of the moving pusher element against some of the underlying cams, guide rails and guide tracks would be a source of wear and noise. Upon failure of the underlying cams or guide components, it would appear that some of those prior art systems could undergo time consuming repair with resulting downtime for the conveying system. 
     Other problems associated with prior sorting systems could include the inability to eject objects from the moving conveying system at ejection speeds which are independent of the speed of the moving conveyor system. Other limitations in the prior art include limitations on the ability to eject a wide range of sizes and shapes of packages and the ability to manipulate the positioning of the object on the conveying surface prior to ejection. 
     As may be seen from the foregoing, prior sorting systems tend to be complex and require significant maintenance upon failure. Moreover, because such systems employ the interaction of rollers, cams and guide rails, such systems would appear to be noisy. Therefore, there has been a need in the art for a sorting system that is simple in construction, which can be easily maintained by removal and replacement of modular sortation assemblies, or conveyor sections housing sortation assemblies, without the use of tools, and which can sort and manipulate a wide range of objects at varying speeds and at relatively low noise levels. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved conveyor sorting system which is simple in construction and may be easily maintained by the quick removal and substitution of failed components and/or by the quick removal of conveyor sections housing failed components. The present invention provides an improved system for efficiently discharging items of varying sizes and weights from a conveying surfaces. The present invention decreases noise levels by employing flexible connectors between sections of a segmented conveyor and by isolating the segmented conveyor from drive and support sprockets or drive and support drums by driving the segmented conveyor with flexible teeth formed from the flexible connectors. These features individually and in combination are aspects of the present invention. 
     Generally described, the present invention provides a conveyor apparatus defining a plurality of supporting surfaces for conveying a plurality of packages placed thereon, the apparatus comprising a frame, a plurality of substantially rigid platform members disposed end to end in spaced apart relation and mounted for movement relative to the frame along a continuous path, each of the plurality of substantially rigid platform members defining at least one of the supporting surfaces in a substantially planar configuration, a plurality of flexible connectors alternating between and connecting the platform members, the flexible connectors each including two platform engaging portions for engaging adjacent platform members and also including a driven portion, and drive means including flexible connector engagement means for engaging the driven portion of the flexible connectors such that the platform members are driven along the path at least partially under the power of the drive means. 
     The present invention also provides a conveyor apparatus defining a plurality of supporting surfaces for conveying a plurality of packages placed thereon, the apparatus comprising a frame, a plurality of substantially rigid platform members disposed end to end in spaced apart relation and mounted for movement relative to the frame along a continuous path, each of the plurality of substantially rigid platform members defining at least one of the supporting surfaces such that it is substantially planar, a plurality of flexible connectors alternating between and connecting the platform members, the flexible connectors each including two platform engaging portions for engaging adjacent platform members and also including a driven portion, and drive means including flexible connector engagement means for engaging the driven portion of the flexible connectors while being isolated from contact with the platform members, such that the platform members are driven along the path at least partially under the power of the drive means. 
     The present invention also provides a conveyor apparatus defining at least one package supporting surface for conveying a package placed thereon from a first to a second location, the apparatus comprising a stationary frame, a package conveying portion (which can be part of a flexible belt or part or all of a rigid platform) movable relative to the frame for defining the supporting surface and including a moving support member, a pusher member for pushing the packages from the supporting surface, force transfer means intermediate the pusher member and the moving support member for transferring force from the moving force transfer means to the pusher member, such that the package may be transferred from the supporting surface. 
     The present invention also provides a conveyor apparatus defining at least one package supporting surface for conveying a package placed thereon from a first to a second location, the apparatus comprising a stationary frame, a package conveying portion movable relative to the frame for defining the supporting surface, a pusher member for pushing the package across the supporting surface, an electric motor attached relative to the package conveying portion for providing energy to urge the pusher member such that it pushes the package across and off of the supporting surface. 
     The present invention also provides a conveyor apparatus defining at least one package supporting surface for conveying a package placed thereon from a first to a second location, the apparatus comprising a stationary frame, a package conveying portion movable along an endless path relative to the frame for defining the supporting surface, a pusher member for pushing a package from the supporting surface, force transfer means for urging the pusher member across the supporting surface, an electric motor attached relative to the frame, the electric motor including at least one movable electrical lead movable with the motor; and at least one stationary electrical connection attached relative to the frame, the movable electrical connection and the stationary electrical connection being configured for relative sliding contact so as to provide electrical power to the electrical motor while the package conveying portion is in motion along the endless path. 
     Therefore, it is an object of the present invention to provide an improved automated conveyor sorting system. 
     It is a further object of the present invention to provide an improved conveyor which may be easily dismantled for repair and maintenance. 
     It is a further object of the present invention to provide a conveyor which operates at reduced noise levels. 
     It is a further object of the present invention to provide an improved ejection mechanism for ejecting items from a conveying surface. 
     It is a further object of the present invention to provide an ejection mechanism for ejecting items from a conveying surface which may be removed from the conveying surface quickly and easily. 
     It is a further object of the present invention to provide an improved apparatus for conveying and sorting items that can be repaired by quickly removing failed sub-assemblies. 
     Other objects, features, and advantages of the present invention will become apparent upon review of the following description of preferred embodiments and the appended drawings and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of an automated sorting conveyor  10  embodying the present invention. 
     FIG. 2 is a side diagrammatic view of an automated sorting conveyor  10 . 
     FIG. 3 is an isolated pictorial view of a platform, or “slat” of the sorting conveyor of FIG.  1 . 
     FIG. 4 is a pictorial view of a flexible connector for connecting the platform of FIG. 3 to adjacent platforms. 
     FIG. 5 is a side elevation view of the joint between two adjacent platforms connected by the flexible connector of FIG.  4 . 
     FIG. 6 is an end view of an alternate form of the flexible connector of FIG. 4 showing an internal slot. 
     FIG. 7 is a pictorial view of a strengthening member for introduction into the slot of the flexible connector of FIG.  6 . 
     FIG. 8 is a cut away side view of a sprocket supporting a slat conveyor. 
     FIG. 9 is an end view of a drive sprocket assembly showing two sprockets connected by an axle. 
     FIG. 10 is a pictorial view of an insert box for receiving teeth formed from the flexible connectors of FIG.  4 . 
     FIG. 11 is a side diagrammatic view of a tension sprocket and tension mechanism. 
     FIG. 12 is an end diagrammatic view of an ejection mechanism embodying the present invention. 
     FIG. 13 is a diagrammatic view of a polarity reverser showing electrical leads and contacts. 
     FIG. 14 is a pictorial view of a cog belt driven ejection mechanism. 
     FIG. 15 is a pictorial view of a belt conveyor-embodying the present invention. 
     FIG. 16 is a pictorial view of a drive drum for supporting the belt conveyor of FIG.  15 . 
     FIG. 17 is a side diagrammatic of an alternate ejection mechanism embodying the present invention. 
     FIG. 18 is a side elevation view of a mounting assembly of the ejection mechanism of FIG.  17 . 
     FIG. 19 is a side diagrammatic view of the ejection mechanism of FIG. 17 mounted on a slat conveyor. 
     FIG. 20 is a pictorial view of a cover plate for the ejection mechanism of FIG.  17 . 
     FIG. 21 is a pictorial view of an alternate cover plate for the ejection mechanism of FIG.  17 . 
     FIG. 22 is a end elevation view of an “off-board” drive assembly for driving the ejection mechanism of FIG.  17 . 
     FIG. 23 is a side diagrammatic view of an “off-board” drive assembly for the ejection mechanism of FIG.  17 . 
     FIG. 24 is a side elevational view of a bellows-type push plate configuration in its retracted configuration. 
     FIG. 25 is a view similar to that of FIG. 24, with the bellows shown expanded. 
     FIG. 26 is a top view of multiple dual-bellows push plate configurations  400  atop a serpentine belt with notches to allow side bending. 
     FIG. 27 is a side view of a conveying system for supporting the belt of FIG. 26 in an “over-under” configuration, although a flat “carosel”-type conveyor design is also possible with the side notches allowing for sideward bending of the conveyor belt. 
     FIG. 28 is a top view of dual-bellows push plate configurations  400  atop rigid platforms connected by flexible intermediate connectors. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like numerals refer to like parts throughout the several drawings, FIG. 1 shows an automated conveying and sorting system  10  embodying the present invention, hereinafter described as “conveyor system”  10 . With reference to FIGS. 1 and 2, the conveyor system  10  includes an endless segmented “belt”  14  comprised of a plurality of platforms or “slats”  18  connected by intermediate flexible connectors  36 . In the form shown in FIGS. 1 and 2, the segmented conveyor belt  14  forms a closed loop. Thus, the slat conveyor  14  may be driven by a drive sprocket  58  and idler sprocket  60 , to be described in detail below. 
     As shown in FIGS. 1,  2 ,  8  and  12 , each slat  18  may include an ejection mechanism  124  to eject items such as parcels (a.k.a. “packages”)  24  off the slat conveyor  14  onto a variety of output destinations such as a receiving chute  16 , a parallel conveyor (not shown), or a non-parallel conveyor (not shown). The parcels  24  may be loaded onto the slat conveyor  14  manually or by an induction conveyor  15 . The ejection mechanism  124  discharges the parcels  24  to the desired destination, in a manner described below. 
     Other subassemblies of the sorting system include a polarity reverser  180 , shown in FIG. 13, which allows the ejection mechanisms  124  to eject items to the left or to the right of the slat conveyor  14  as directed by a programmable logic controller (PLC) (not shown). An idler (a.k.a. “tensioning” sprocket  60 , shown in FIGS. 2 and 11, provides necessary tension in the slat conveyor  14 . The assemblies and subassemblies thus far noted and shown will now be described in detail. 
     Referring now to FIGS. 1,  2 ,  3 ,  4  and  5 , the endless slat conveyor  14  is comprised of a plurality of slats  18  (a.k.a. “platforms”). In the preferred form shown, the slats  18  are formed from extruded aluminum. It is understood that the slats  18  may be formed from other suitable materials such as plastic or steel. Although other configurations are contemplated, as shown in FIG. 3, each slat  18  includes an elongate pusher member slot  22  extending along the length of the slat  18  transverse to the direction of travel of the conveyor, as shown in FIGS. 1 and 2. As will be described below, the elongate pusher member slot  22  is included in slat  18  for the placement and operation of ejection mechanism  124 . It should be understood that the slat  18  may be constructed without the pusher member slot  22  where the slat  18  will not house an ejection mechanism  124 . 
     As shown in FIG. 3, the leading and trailing edges of each slat  18  can include elongate connector slots  28  formed along the length of the slat  18  transverse to the direction of travel of the slat conveyor  14 . As shown in FIGS. 3 and 5, the elongate connector slots  28  are comprised of an upper member  29  and a lower member  30 , which combine to retain a flexible connector as discussed below. As can be seen in FIGS. 3 and 5, lower member  30  is inwardly offset from upper member  29  to provide some clearance for flexing and bending about flexible connector  36  and relative to adjacent slats  18 , as shown in FIG.  8 . 
     Referring now particularly to FIGS. 4,  5  and  6 , each slat  18  is connected to adjacent slats  18  by a flexible connector  36  which is inserted into the connector slots  28  of adjacent slats  18  as shown in FIG.  5 . The flexible connector  36  is an elongate flexible member which runs substantially the width of the slats  18  and transverse to the direction of travel of the slat conveyor  14 . The flexible connector  36  is formed from extruded rubber or plastic, but it is understood that other suitably strong materials may be utilized. 
     In an alternate form, as shown in FIG. 6, an elongate slot  48  may be included in flexible connector  36 . An insert  44 , as shown in FIG. 8, may be inserted or molded into the elongate slot  48  of flexible connector  36  to provide enhanced strength to the flexible connector  36 . The insert  44  may be constructed of a suitably strong material such as Kevlar or spring steel. 
     As can be seen from the end view of the flexible connector  36 , as shown in FIGS. 5 and 6, the flexible connector  36  can be comprised of a vertical stem  37  and a “bow tie” shaped cross member running transverse to vertical stem  37 . The “bow tie” shaped cross members forms flanges  39  which slidably engage the elongate connector slots  28  of the slats  18  as shown in FIG.  5 . Referring still to the end view of flexible connector  36 , shown in FIG. 5, the lower terminus of the vertical stem  37  of the flexible connector  36  forms a tooth  40  for engaging complementary notches in a drive sprocket or drive drum in order to drive the slat conveyor  14 , as shown in FIG.  5 . Although the flanges are essentially trapezoidal in shape, it should be understood that other headed configurations are likewise contemplated. Other non-headed flanges are likewise contemplated if suitable attachment means are provided. 
     Referring now to FIGS. 1,  2 , and  8  and  9 , the conveyor belt  14 , comprised of slats  18  and connected by flexible connectors  36  as described above, is connected into a closed loop and is supported by a drive sprocket  58  and an idler sprocket  60 . The conveyor  14  is driven by the drive sprocket  58  by engagement of the teeth  40  of flexible connectors  36  with corresponding notches  68  formed on the drive sprocket  58  and the idler sprocket  60  as shown in FIGS. 8 and 11. The use of flexible connectors  36  to connect the slats  18  and to drive the slat conveyor  14  via the flexible teeth  40  see FIGS. 4 and 5 of the flexible connectors  36  allows for increased speed and reduction of noise by isolation of each slat from adjacent slats and by isolation of direct contact of the slat conveyor  14  from the drive sprocket  58  and the idler sprocket  60 . The use of the flexible connectors  36  to connect the slats  18 , as described above, also facilitates quick and easy removal and replacement of individual slats  18  for maintenance and repair. As may be understood, the slats  18  may be removed by slidably withdrawing the flexible connectors from each end of a given slat  18 , and then removing the slat  18 . 
     As described above, the slat conveyor  14  is supported by the drive sprocket  58  and the tension sprocket  60 , both of which include notches for receiving inwardly extending teeth  40  of each flexible connector  36 . In an alternate form as shown in FIG. 10, metal insert boxes  76  may be inserted into the tooth notches  68  of drive sprocket  58  and the tension sprocket  60 . Metal insert boxes  76  provide for a smooth preformed tooth notch for the teeth  40  of the flexible connectors  36 . The metal insert boxes  76  may be secured to the drive sprocket  58  and the tension sprocket  60  by welding, bolting, riveting, or an other suitable attachment method. The metal insert boxes  76  may be constructed out of aluminum or other suitably strong material. 
     As shown in FIG. 9, the drive sprocket  58  is comprised of sprockets  58   a  and  58   b  connected by an axle  62 . In the preferred form shown in FIG. 9, the drive pulley  64  is mounted to the axle  62  outside drive sprocket  58   b . The drive sprocket  58  is driven by a drive motor (not shown). As shown in FIGS. 2 and 11, the slat conveyor  14  is supported at the end opposite the drive sprocket  58  by the tension sprocket  60 . The tension sprocket  60  provides necessary tension in the slat conveyor  14 , and conversely, releases the tension in the slat conveyor  14  in order to remove individual slats  18  for maintenance or repair. 
     As shown in FIG. 11, the tension sprocket  60  includes a tension mechanism  82 . The tension mechanism  82  is comprised of a compression spring  88  which is retained by forward spring retaining member  89 . At the rear end of the compression spring  88  is a spring compression and release member  90 . The spring compression and release member  90  is actuated by a hydraulic cylinder  95  which contains hydraulic fluid  100 . As is well, known to those skilled in the art, a suitable pneumatic cylinder may be used in place of hydraulic cylinder  95 . Tension in the slat conveyor  14  may be decreased by manually activating the hydraulic cylinder, or operation of the tension mechanism  82  may be directed by a programmable logic controller (not shown). 
     Referring now to FIGS. 1,  2 ,  8  and  12 , each slat  18  of the slat conveyor  14  can contain a built-in ejection mechanism  124 . As previously described, the ejection mechanism  124  may be used to discharge items such as parcels  24  from the slat conveyor  14  to a variety of output destinations. The ejection mechanism  124 , as shown in FIG. 12, includes a pusher member (a.k.a. “pusher plate”)  130  for pushing items off the upwardly-directed surface of the slat conveyor  14 . As shown in FIG. 8, the pusher member  130  is T-shaped and runs substantially across the length of the slat  18  transverse to the direction of travel of the slat conveyor  14 . 
     Referring now to FIGS. 8 and 12, the lower stem of the T-shaped pusher member extends down through the pusher member slot  22 . As shown in FIG. 12, beneath the slat  18 , a threaded opening  142  in the pusher member stem  136  threadably engages a screw actuator (a.k.a. “lead screw”)  148 . The screw actuator  148  is powered by an electric gear motor  154 . The screw actuator is rotatably mounted to the slat  18  at the end opposite the electric gear motor  154  by a bearing mount  160  as shown in FIG.  12 . The electric gear motor  154  is mounted to the slat  18  by a gear motor mount  164 . Thus, as shown in FIGS. 8 and 12, the ejection mechanism is mounted on board the individual slat  18  and travels with the slat  18  as a part of the slat conveyor  14 . 
     As shown in FIG. 8, the drive sprocket  58  and tension sprocket  60  include gear motor notches  70  to receive the electric gear motor  154  and screw actuator  148  as the slat conveyor  14  is driven over the drive sprocket  58  and the tension sprocket  60 . In an alternate form shown in FIG. 14, the pusher member  130  may be actuated by a cog belt  149  which engages a complementary set of teeth (not shown) disposed on the lower stem of the pusher member  130 . 
     Referring now to FIGS. 2,  12 , and  13 , a pair of movable electrical power contacts  170  are attached to the electric motor  154 . The electrical power contacts  170  extend outwardly from the ejection mechanism and engage fixed power strips  176  which are positioned adjacent to desired discharge locations. As shown in FIG. 13, electrical contacts  170  are spring loaded to provide continuous and even contact between the contacts  170  and the fixed power strips  176 . Thus, energization of the electrical contacts  170  via the fixed power strips  176  energizes the electrical gear motor  154  which in turn rotates the screw actuator  148  to drive the pusher member  130  across the slat  18  at a high rate of speed. 
     If desired, two or more pusher members may be actuated simultaneously to eject a large or long parcel from the conveying surface. Because the ejection mechanism  130  is driven independently of the underlying conveyor, a PLC may direct the ejection mechanism  130  to eject items at varying speeds as may by desired. As is well known to those skilled in the art, the PLC may vary the speed of the ejection mechanism drive motor by positively or negatively ramping the electric current supplied to the motor. 
     Referring back to FIG. 13, positioned between the fixed power strips  176  and the gear motor power source (not shown) is a polarity reverser  180 . As shown in FIG. 13, the polarity reverser  180  includes a pair of fixed contacts  170  which engage moveable contacts  188  mounted on the switch  190 . An electric solenoid  194  is connected to the switch  190 , which at the direction of the programmable logic controller may actuate the switch, and thus reverse the polarity of current flowing through fixed power strip  176  and to the electrical contacts  170 , as shown in FIG.  13 . By reversing the polarity to the electric gear motor  154  by the polarity reverser  180 , as described, the pusher member  130  may be returned to a starting position, as shown in FIG.  12 . The polarity reverser  180  also may be used to cause the pusher member  130  to discharge an item such as parcel  24  to the right or to the left of the slat conveyor  14 , as desired. 
     A second embodiment of the present invention is shown in FIGS. 15 through 23, which portray an automated sorter system  200 , which may utilize a segmented slat conveyor as described in the first embodiment or which may utilize a flat drum-driven conveyor belt. As with slat conveyor of the first embodiment, a slat conveyor or a belt conveyor may comprise a plurality of ejection mechanisms for ejecting parcels to a variety of output destinations. In contrast to the “on-board” electric generator  154  of the first embodiment, the present embodiment utilizes a “off-board” pushing member driving means, to be described below. 
     As shown in FIGS. 15 and 17, the ejection mechanisms  220  are mounted on the upper surface of the conveyor belt  225 . As shown in FIG. 19, the ejection mechanism of this embodiment may also be mounted on a slat conveyor  14 . This configuration allows the belt conveyor  225  or slat conveyor  14  to be moved in alternate configuration, such as a serpentine configuration (not shown) without having equipment underneath the slat or conveyor to hamper movement. 
     As shown in FIGS. 17 and 18, ejection mechanism  220  is attached to conveyor belt  225  by inserting mounting rods  230  through corresponding holes (not shown) in the conveyor belt  225 . As shown in FIGS. 17 and 18, beneath conveyor belt  225 , the mounting rods are placed through flexible inserts  235  and are retained by spring washers  240  and retaining pins  245 . The flexible inserts  235  maintain snug, but flexible contact between the ejection mechanism  220  and the conveyor belt  225  or slat  18 . 
     As shown in FIG. 17, a conveyor superbed  226  may be provided with pre-formed receptacles for receiving the retainer rods  230  of the ejection mechanism  220 . As shown in FIGS. 15 and 16, where the second embodiment is employed using a conveyor belt  225 , drive drum  227  and tail drum  228  include first and second grooves  229  to receive the mounting rod assembly  231 . 
     Referring back to FIG. 17, the ejection mechanism  220  is comprised of a pusher member  130  actuated by a screw actuator  148 . A sheave  250  is attached to a drive shaft  252  at a first end of the screw actuator  148 . Bearing mounts  255  are provided at both ends of the screw actuator  148 , which are attached to the mounting rods  230 . As shown in FIG. 17, a coil spring retractor  260  is mounted on the drive shaft  252  between the sheave  250  and the actuator screw  148 . The coil spring retractor  260  is wound as the pusher member  130  is actuated away from the sheave  250 . Upon the cessation of rotation of the sheave  250  to drive the pusher member  130 , the coil spring retractor unwinds to reverse the rotation of the screw actuator  148  and return the pusher member  130  to the starting position at the sheave end of the ejection mechanism  220 . 
     As shown in FIGS. 17 and 20, a cover plate  261  is attached to the ejection mechanism  220  to protect the ejection mechanism  220  and to provide a smooth transitional surface between the conveyor belt  225  or slat  18  and the pusher member  130 . As shown in FIG. 20, the cover plate  261  comprises first and second bearing mounts  255  and a screw actuator cavity  264  through which the screw actuator  148  is placed. As shown in FIG. 21, an alternate cover plate  261  is provided. 
     Referring now to FIGS. 22 and 23, rotational force for the sheave  250  is provided by a plurality of drive assemblies  265  which are mounted externally to the conveyor at each discharge location. As shown in FIG. 22, the drive assembly  265  includes an upper drive motor  270  and a lower drive motor  275  mounted on the upper and lower mounting plates  280  and  285 . As shown in FIGS. 22 and 23 each of the upper and lower drive motors  270  and  275  drive a first drive pulley  290 . A support pulley  295  is mounted in spaced apart relation to drive pulley  290 , as shown in FIGS. 22 and 23. Drive pulleys  290  and support pulleys  295  support upper and lower drive belts  300  as shown in FIGS. 22 and 23. The drive belts  300  are driven by drive motors  270  and  275 . 
     Referring still to FIGS. 22 and 23, the upper and lower mounting plates  280  and  285  are pivotally mounted to a stationary support (not shown) external of and adjacent to the conveyor  210 . A tension spring  305  is attached to the upper mounting plate  280  and to the lower mounting plate  285  to urge the upper and lower drive belts  300  together and onto the sheave  250  as shown in FIGS. 22 and 23 during operation of the ejection mechanism, to be described below. As shown in FIG. 23, a separator wedge  310  is operatively mounted between the upper and lower mounting plates  280  and  285  to oppose the tension spring  305  and separate the upper and lower drive belts from the sheave  250  when the ejection mechanism is not in operation. An opening spring  315  is attached to the separator wedge  310  to draw the separator wedge into the open position as shown in FIG.  23 . Power to the upper and lower motors  270  and  275  is supplied by an external source (not shown) and is controlled by a PLC as described in the first embodiment. As shown in FIG. 23, the separator wedge  310  is mechanically retracted by energizing a solenoid  320  to allow the upper and lower drive belts  300  to engage the sheave  250 . 
     Referring now to FIGS. 24 and 25, a “push plate” conveying segment is shown as  400  in FIGS. 25-28. In FIGS. 24,  25  and  26 , two or more horizontally-acting bellows members are attached relative to the top surface of a conveyer belt  402  to provide a pushing function to a package  420  situated atop the top surface of the conveyor belt  402 , such that it is pushed off the belt. In FIG. 28, rigid platforms  411  are used to support the bellows configurations  400 . 
     Referring now particularly to FIGS. 24 and 25, the configuration  400  includes a conveyor belt  402 , a chamber housing  403 , bellows members  404 , and a push plate  401 . The air chamber housing  403  of the push plate conveying segment  400  is attached to and moves with the upper surface of the belt  402 , and is configured such that it fits under the edge restraint  470 . The air chamber housing  403  defines an interior air chamber  405  which is supplied air through a chamber inlet port  406  and itself supplies air to two chamber outlet ports  407 . Each of the two chamber outlet ports  407  supplies air from the chamber  405  to a corresponding one of the two horizontally-oriented members  404 . In one preferred embodiment, the belt  402  is composed of flexible conveyor belt material. 
     The bellows members  404  operate such they extend along their lengths upon the introduction or air, such that their two ends are separated along the width of the package conveying segment  400 . The bellows members  404  are side-by-side in a parallel relationship, and each has one end attached to the air chamber housing  403  and the other attached to the push plate  401 . Upon the energizement of the bellows members  404  from their retracted positions shown in FIG. 24 to their extended positions shown in FIG. 25, the push plate  401  is itself pushed substantially across the width of the belt  402  of the push plate conveying segment  400 . Should a package be positioned on the belt  402  beside the push plate  401 , it is discharged from the belt as shown in FIG. 25 by the bellows members  404 . Energizement of each bellows member is provided by opening a valve such as  416  from its position shown in FIG. 24 to its position shown in FIG.  25 . 
     Referring back to FIG. 1, the automatic sorting system  10  can be operated under the control of a digital controller, which may be a programmable logic controller (PLC) or a general purpose microprocessor which is found in a personal computer. Methods for programming such controllers to operate a sorting system of the type disclosed therein are conventional and known to those skilled in the art. 
     As described in the preceding section, the slat conveyor  14  is driven by a drive sprocket  58 . As previously described, motive force is applied to the slat conveyor  14  by engagement of notches in the drive sprocket  58  with the flexible teeth  40  of slat connectors  36 . During operation, adequate tension is maintained in slat conveyor  14  by the tension mechanism  82  connected to tension sprocket  60 . As increased tension in the slat conveyor  14  is required, the PLC will direct the actuation of the hydraulic cylinder  95  to compress the tension spring  88  and thereby apply force against tension sprocket  60  as shown as in FIG.  11 . Conversely, if the slat conveyor  14  needs to be slackened in order to remove an individual slat  18  or an ejection mechanism  124 , the hydraulic cylinder may be directed manually or by the PLC to release the tension in the tension mechanism  82  and thereby produce slack in the slat conveyor  14 . 
     In order to remove an individual platform or “slat”  18  from the slat conveyor  14  or to remove a slat  18  housing an ejection mechanism  124  for maintenance, repair, for other reasons, the slat conveyor  14  is slackened, as described, and the slat connectors  36  connecting the subject slat  18  to adjacent slats  18  are pulled out of the corresponding connector slots  28  as shown in FIGS. 3,  4 , and  5 , allowing the subject slat to be removed. 
     In operation, the number of and location of ejection mechanisms  124  and an identification code for each ejection mechanism are input into the controller memory when movement of the slat conveyor begins. Parcels  24  are induced sequentially onto the upstream end of the slat conveyor  14  either manually or automatically by an induction conveying system as illustrated by induction conveyor  15  shown in FIGS. 1 and 2. A destination code for each parcel is entered into the controller memory using a keypad (not shown), voice recognition input device (not shown), or an optical code reader before the parcel is placed onto the slat conveyor  14  as described above. Depending on the side of the slat conveyor  14  to which the parcel  24  is to be discharged, the PLC will cause the pusher member  130  of the ejection mechanism  124  of the slat  18  onto which the parcel  24  will be loaded to move to a left or right position by actuating the pusher member  130  via the electric gear motor  154  and screw actuator  148 , as described above. The parcel  24  is then placed onto the slat conveyor  14  onto the slat  18  with the pusher member  130  poised to discharge the parcel  24  as directed by the PLC. As the parcel  24  reaches the desired output destination, such as receiving chute  16 , as shown in FIG. 1, the spring loaded electrical contacts  170  attached to the electric gear motor  154  will engage the fixed power strips  176 , as shown in FIGS. 2,  12  and  13 . At the direction of the PLC, the electric gear motor  154  will be energized via the fixed power strips  176  and the electrical contacts  170  to rotate the screw actuator  148  and actuate the pusher member  130  to discharge the parcel  24  off the slat conveyor  14  onto the receiving chute  16 . 
     After the parcel  24  is discharged onto the receiving chute  16 , as described, the PLC may reverse the polarity of the current to the electric gear motor  154  to return the pusher member  130  to the start position, as described above, or the PLC may leave the pusher member  130  in its current position in order to discharge a parcel subsequently loaded and directed to the opposite side. 
     It should be understood that two or more pusher members  130  may be assigned to a single parcel  24  and that the pusher members  130  may be actuated simultaneously to such a single parcel from the slat conveyor  14 . This procedure is particularly useful for heavier or longer parcels. Additionally, where two or more pusher members  130  are assigned to a single parcel, the pusher members  130  may be actuated sequentially in order to rotate a parcel so as to facilitate it&#39;s discharge onto the receiving chute  16  with a desired end of the parcel forward. 
     As with the first embodiment, operation of the alternate ejection mechanism  220  described in the second embodiment can be controlled by a programmable logic controller. As a parcel  24  moves adjacent to desired output discharge location, as described for the first embodiment, the sheave  250  of the ejection mechanism  220  moves into position between upper and lower drive belts  300  of the off-board drive assembly  265 . The PLC causes the power source to energize the upper and lower drive motors  270  and  275 , shown in FIGS. 22 and 23, and the solenoid  320  is energized to cause the separator wedge  310  to retract as shown in FIG.  22 . As the separator wedge  310  retracts, the tension spring  305  pulls the upper and lower mounting plates  280  and  285  and upper and lower drive belts  300  together to engage the sheave  250  as shown in FIGS. 22 and 23. The sheave  250 , thus engaged, rotates the actuator screw  148  and causes the pusher member  130  to push the parcel  24  off the conveyor belt  225  and onto a discharge area (not shown). 
     As the pusher member  130  traverses the conveyor belt  225  or slat  18  as described, the coil spring retractor  260  retracts the pusher member  130  back to the starting position adjacent to the sheave end of the screw actuator  148  as shown in FIG.  17 . 
     For purposes of maintenance or removal of the ejection mechanism  220  from the conveyor belt  225  or from the slats  18 , the ejection mechanism  220  may be quickly and easily removed without the use of tools. As shown in FIGS. 17 and 18, the ejection mechanism  220  may be removed from the conveyor belt  225  or from the slats  18  by removing the retainer pin  245 , the spring washer  240  and the flexible insert  235 , and then lifting the ejection mechanism  220  off the conveyor belt  225  or slat  18 . 
     While the present invention in its various aspects has been described in detail with regard to preferred embodiments thereof, it should be understood that variations, modifications and enhancements can be made to the disclosed apparatus and procedures without departing from the spirit and scope of the present invention as defined in the appended claims.