Abstract:
A robotic parts handler system for removing containers filled with articles from a sorting, feeding and/or stacking apparatus such as a mail or package sorting apparatus, and moving the container to a selected location for insertion into another conveying system, transport device, carrier, or other apparatus at extremely high speeds.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 09/363,622 filed on Jul. 29, 1999 now U.S. Pat. No. 6,257,821 issued Jul. 10, 2001, incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to robotic parts handler system for removing containers filled with articles such as mail or packages from a high speed sorting, feeding and/or stacking apparatus and conveying the container, tray, or a cartridge for containing flat articles such as is described in U.S. Pat. No. 5,833,076 by Harres et al. issued on Nov. 10, 1998 and incorporated herein by reference, to a selected location for insertion into another conveying system, transport device, carrier, or other apparatus at extremely high speeds. 
     2. Background Information 
     Articles of mail and packages are typically sorted, stacked, and conveyed by apparatus such as described in U.S. Pat. Nos. 5,634,562; 5,582,324; 5,562,195; 5,422,821; 5,201,397; all of which are incorporated by reference herein. A typical sorting and stacking apparatus is shown in FIGS. 2 and 3 consisting of a rectangular frame utilizing a plurality of receptacles and roller belt systems to convey, sort, and stack postal letters in accordance with a bar code or other indicia indicative of a particular destination. The articles are then fed into containers or boxes, whereby individuals detach the boxes upon filling, stack them on a cart, conveyor belt, or other means of moving, and transport the containers filled with mail articles to a distribution point. 
     The present mail distribution system is inherently inefficient in that the sorting, stacking, and conveying system is a highly automated high speed system capable of sorting and moving articles in a few seconds; however, the containers are manually carried by mail persons. Thus, the high speed equipment is frequently idle due to the inability of the mail persons to remove and replace the containers at a corresponding high rate of speed. 
     The present invention eliminates the necessary of mail persons to work in close proximity to the high speed operating equipment thereby eliminating the hazards associated therewith and the strenuous physical activities associated with moving the containers from the sorting apparatus to the distribution point manually. Moreover, conventional equipment utilizes a number of actuators, usually one for each mail slot or port requiring extensive maintenance and a large capital investment in equipment. 
     SUMMARY OF THE INVENTION 
     The present invention defines a robotic parts handling system having a platform forming a base including at least one linear servo magnetic motor affixed to and extending along the side beneath the platform. The platform is supported by a track including a first master rail and a second minor balancing rail. A plurality of supporting rollers supporting and hold the platform to the first master rail and the second minor balancing rail. A plurality of magnets mounted along the length of the first master rail are in cooperative magnetic engagement with the at least one linear servo magnetic motor. A plurality of positioning rollers mounted to the platform maintain a constant distance between the linear servo magnetic motor and the magnets mounted to the first master rail. A computer control unit controls and coordinates movement of the robot along the rails and the operation of the end effectors. A magnetic strip provides a means in close proximity to the rail for generating pulses readable by a reader in communication with the control unit for positioning the platform at selected positions upon the rail. A frame mounted upon the platform includes at least one pair of vertical rails spaced apart from and in alignment with one another. A pair of slide members, each one including a plurality of rollers cooperatively engage the vertical rails. A pair of timing belts provide means extending along the vertical rails in cooperative engagement with the slide members for moving the slide members up and down independently of one another along the Y-axis. A saddle having distal ends extending in between the vertical rails attaching to the slide members permit the saddle to be tiltable from side to side. An air cylinder, hydraulic cylinder, or servo driven ball screw (electric cylinder) provides a means for tilting the saddle from front to back along the x-axis. At least one end effector mounted onto the saddle includes means for engaging and removing a container from a preselected position on one side of the platform and transferring the container to the opposite side of the platform and positioning and releasing the container in a selected location. One such means includes a conveyor having timing belts with protrusions for cooperative engagement with opposing depressions formed on the bottom of a cartridge container. 
     The present invention defines a high speed robotic container handling system having a digital magnetic positioning system, a platform frame having a linear servo motor thereon moveable along a pair of rails one of which includes magnets affixed thereto. The platform supports a pair of frame members supporting a tiltable saddle which supports one or more end effectors with actuators and conveyor capacity for interfacing with containers or cartridges filled with mail or the like held in multiple bins or slots on either side of the rails at selected sites up or down the track rails. In one preferred embodiment, the robotic container handling system removes containers filled with articles from the sorting apparatus, transfers and inserts them within a buffer and releasing them therein, moves to a position in alignment with the buffer containing an empty container(s) and extracts the container(s) therefrom, and inserts the container(s) into an empty location of the sorting machine; thereafter, repeating the cycle. 
     It is an object of the present invention to provide a robot to interface with a container, tray, or cartridge for receiving letter mail from an existing belt distribution system that guides the mail pieces into the tray at speeds up to 10 pieces per second. 
     It is an object of the present invention to provide a robot to interface with a container, tray, or cartridge wherein the tray has an onboard lock-up means that retains the mail as the tray is used for off-system storage and/or transportation. 
     It is an object of the present invention to provide an end effector for manipulating the tray and interacting with the mail belt system and the tray at high speed. 
     It is an object of the present invention to provide a means for loading the tray containing mail onto the end effector, transport it to a position determined by an overall system controlling computer and unload the tray containing mail at a selected location at a selected time. 
     It is an object of the present invention to provide a conveyor module as a part of the end effector assembly which utilizes a belt having protrusions with interlock with opposing cavities and/or protrusions on the bottom surface of the tray allowing trays weighing in excess of twenty-five pounds to be handled at very high speeds and accelerations. 
     It is an object of the present invention to provide a robot having a platform base powered by linear servo magnetic motors providing a very high acceleration and deceleration and the ability to park the entire system consistently within 0.010 inches of a preselected position. 
     It is an object of the present invention to provide a robot powered by a linear magnetic motor which is cooperatively magnetically engageable with a master rail having a plurality of permanent magnets affixed thereto together with nonferrous guide rollers which maintain a necessary selected gap of about 0.020 of an inch between the motor and rail magnets in order to drive the unit back and forth in the X-axis with high speed and precision. 
     It is an object of the present invention for the linear motor and magnetic rail system to be adaptable with the platform of the robot for moving the robot over flat surfaces such as a floor with the aid of a second minor rail or balancing rail and for the entire track and robot to be suspended above the ground. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the several views and wherein: 
     FIG. 1 is a perspective view of the robotic container handling system of the present invention; 
     FIG. 2 is a top view showing the sorting and stacking apparatus having a platform base and end effector assembly movable upon a magnetic track rail system having a vertical lifting and stacking assembly including effector means for distributing and conveying articles; 
     FIG. 3 is a perspective view of a computer control center for the present invention together with a mail sorting apparatus on one side of the track and a storage unit on the opposite side of the track; 
     FIG. 4 is a sectional view along lines  4 — 4  of FIG. 2 showing the robotic handler system including effector head and platform base on a track with the effector head and conveyor assembly in the raised position in phantom lines, showing the effector head tilting and extending outwardly from the frame in phantom lines, showing support rail rollers on the top and inside of the track rail, and the linear servo motor and positioning roller on the outside of the opposing track rail; 
     FIG. 5 is a top partial cutaway view of the robot showing a pair of effector head assemblies supported by the saddle connected to the frame by slide members held within guide rails by rollers being moved in the Y-axis by a belt all being supported by the platform base setting on a master rail showing the nonferrous metal positioning rollers resting on the vertical portion of the master rail for holding the linear motors a selected distance from the magnetic plates affixed to the outside surface of the master rail and showing rubber support rollers mounted onto the minor balancing support rail; 
     FIG. 6 is a partial cutaway view showing the guide rollers of the platform base with the positioning guide rollers and rubber support rollers in cooperative engagement with the master rail, showing the brake, magnets, linear servo motor, magnetic strip, and gap between the linear servo motor and positioning rollers; 
     FIG. 7 is a partial cutaway view of FIG. 19 showing the guide rollers, brake, and servo motor with respect to the master rail; 
     FIG. 8 is a side view showing the bank of permanent magnets attached to the master rail; 
     FIG. 9 is a side view showing a pair of effector head assemblies in (phantom lines) supported by the saddle connected to the frame by trunions and supported by the platform base mounted onto the magnetic rails wherein a saddle is shown in phantom lines in the raised and pivoted position; 
     FIG. 10 is a top sectional view showing the of a rail in cooperative engagement with the rail brake in the open unlocked position; 
     FIG. 11 is a top sectional view of the brake of FIG. 6 in cooperative engagement with the rail brake in the closed locked position; 
     FIG. 12 is a top view of the tiltable saddle supported by vertical support columns and movable up and down by rollers cooperatively engaging the vertical columns by trunions and powered by rotary servo motors; 
     FIG. 13 is a side view of the tiltable saddle of FIG.  12  and the vertical support columns showing the saddle connected to the columns by trunions and showing a pair of rotary servo motors for raising and lowering each side of the saddle independently; 
     FIG. 14 is a side view of the cylinder shown in FIGS. 12 and 13 used for tilting the saddle forward or rearward; 
     FIG. 15 shows a top view of the guide rollers mounted onto the saddle trunion supporting the end effector for sliding up and down the guide rails mounted to the vertical support rails of the frame having a pair of opposing fail safe brake pads extending against the interior surface of the support column to stop vertical motion of the assembly upon loss of power; 
     FIG. 16 is a perspective rear end view of a cross slide module of the present invention showing the cross slide saddle, base, rails, drive pulley, timing belt, pillow block, and drive motor; 
     FIG. 17 is a perspective front end view of the cross slide module of FIG. 16 showing the ball screw, ball screw cover, and ball screw support bearing housing; 
     FIG. 18 is a top view of FIG. 16 showing the cross slide module; 
     FIG. 19 is a sectional view of FIG. 18 showing the motor drive of the cross slide module; 
     FIG. 20 shows a sectional view of a the cross slide module of FIG. 18 showing a portion of the servo driven ball screw is assembly; 
     FIG. 21 is a rear end view showing a saddle supporting a pair of cross slide modules having conveyor modules mounted thereon with a pair of container cartridge trays shown in phantom lines supported thereon; 
     FIG. 22 is a front end view of the cross slide module showing the ball screw and slide rods that move the cross slide saddle back and forth on the cross slide base; 
     FIG. 23 is a rear end view of the cross slide module showing the motor and drive train for moving the cross slide saddle back and forth over the slide rods mounted on the cross slide base; 
     FIG. 24 is a front end perspective view of a conveyor module of the effector head assembly; 
     FIG. 25 is a rear end perspective view of the conveyor module of FIG. 24; 
     FIG. 26 is a top view showing the conveyor module of FIG. 24 showing the motor and belt drive of the conveyor module; 
     FIG. 27 is a side view of FIG. 26 showing the conveyor module with the motor and belt drive whereby protrusions of the belt are engaging the indentations of the container cartridge shown in phantom lines; 
     FIG. 28 is a side view showing a cross slide module supporting the conveyor module including a container cartridge whereby protrusions of the belt are engaging the indentations of the container cartridge shown in phantom lines; 
     FIG. 29 is a rear perspective view of the drop gate actuator which mounts to the cross slide module of the effector end assembly showing the drop gate actuator in the down position; 
     FIG. 30 is a front perspective view of the drop gate actuator which mounts to the cross slide module of the effector end assembly showing the drop gate actuator in the extended “up” position; 
     FIG. 31 is a partial sectional view of the drop gate actuator assembly taken through FIG. 33 showing the curved slide cam and rollers and the drive motor; 
     FIG. 32 is sectional view taken through FIG. 33 showing the drive pulleys and belt for operating the drop gate assembly; 
     FIG. 33 is an front end view of the drop gate actuator assembly showing the drop gate top and bottom links in the raised position and also showing them in the lowered position with phantom lines wherein the engageable mail cartridge container or tray on the end effector conveyor are also shown in phantom lines and rotated 90 degrees for viewing clarity; 
     FIG. 34 is a top view showing the drop gate module, and showing the stack support actuator assembly in phantom lines of the end effector; 
     FIG. 35 is a side view of the drop gate actuator assembly mounted onto the end effector slide plate showing the arm in the raised position engaging the drop gate lever of the cartridge container in the raised position wherein the drop gate is lowered for receiving mail from a sorting apparatus; 
     FIG. 36 is a front perspective view showing a stack support actuator; 
     FIG. 37 is a rear perspective view showing the stack support actuator of FIG. 36; 
     FIG. 38 is a side view showing the stack support actuator with the cam track for lifting and engaging the fork rod with a receiver means extending through the bottom of a mail cartridge container; 
     FIG. 39 is a top view showing the stack support actuator assembly of FIG. 38 comprising a “rack and pinion” assembly wherein a fork extending from the distal end of a rod or “rack” is extendable back and forth by a pinion gear driven by a motor with a gear belt pulley and gear belt (shown in phantom lines) for driving another gear drive pulley attached to the pinion gear; 
     FIG. 40 is a front view of the effector head and stack support actuator of FIGS. 38 and 39, wherein a fork extending from the distal end of a rod or “rack” is extendable back and forth by a pinion gear driven by a motor. The mounting plate and drop gate assembly are shown in phantom lines; 
     FIG. 41 is a sectional view of the stack support actuator taken through FIG. 38 showing the drive mechanism and timing belt for the cam assembly and cam track; 
     FIG. 42 is a section along lines  43 — 43  taken through FIG. 40 showing the motor and drive belt (in phantom lines), and pulleys; 
     FIG. 43 is a sectional view taken through FIG. 42 showing the guide rollers on the cam track; 
     FIG. 44 is a top view of a pair of end effectors showing a pair of stack support actuators, a pair of drop gate actuators, and a pair of conveyor modules mounted on the cross slide module showing the saddle and trunions in phantom lines; 
     FIG. 45 is a perspective view of FIG. 44 showing details of the pair of end effectors with a pair of stack support actuators, a pair of drop gate actuators, and a pair of conveyor modules mounted on the cross slide module; 
     FIG. 46 is a front view of the cartridge showing the horizontal drop gate which is cooperatively engagable with the drop gate actuator of the end effector; 
     FIG. 47 is a rear end view of the cartridge which abuts and is cooperatively engageable with a mail sorter; 
     FIG. 48 is a top view of a cartridge showing the slot having a longitudinal notched member therein and showing a stack support in cooperative engagement therewith, and the peripheral drop gate pivot rod extending therearound; 
     FIG. 49 is a side view of the cartridge showing the drop gate rod pivot point; 
     FIG. 50 is a top view of a clearing gate actuator; 
     FIG. 51 is a side view of the clearing gate actuator of FIG. 50; 
     FIG. 52 is an end view of the clearing gate actuator of FIG. 34; 
     FIG. 53 is a side view of the platform base of the present invention showing the use of fail safe brakes mounted to each end of the platform for easy maintenance; and 
     FIG. 54 is an end view of the platform showing the master rail, the linear servo motor, the magnets, the nonferrous positioning rollers and antifriction bearings therein, the rubber support rollers, and the brake pads on each side of the rail. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Articles of mail and packages are typically sorted, stacked, and conveyed by apparatus such as described in U.S. Pat. Nos. 5,634,562; 5,582,324; 5,562,195; 5,422,821; 5,201,397. A typical mail sorting apparatus is shown in FIGS. 2 and 3 and denoted as prior art. The present robotic container handling system  10  as best shown in FIG. 1, provides a means of handling the mail or other articles deposed in containers or cartridges. The present invention comprises a platform base movable upon a magnetic track or rail system having a vertical lifting and stacking assembly including effector end means for distributing and conveying articles. The distributing means consists of a effector head assembly  12  having a belt conveyor module  14 , clearing gate module  15 , drop gate module  17 , stack support module  90 , all mounted upon a cross slide module  23  to convey, sort, and stack postal letters in accordance with a bar code or other indicia indicative of a particular destination. These articles are then fed into containers, cartridges, or boxes  16 . The present invention robotic container handling system, (“robot”),  10  removes the containers  16  from the sorting apparatus  18  and conveys the containers  16  filled with articles, such as letters, to a selected distribution point defining a buffer or storage unit  20  having container receivers  21  or pockets therein which engages a container or cartridge  16 , such as shown best in FIGS. 27-28, and returns in a matter of seconds to insert the container  16  into a preselected position of the sorting apparatus  18  selected by a computer control system  11  which may be mounted piggyback onto an end of the frame  40  or be contained in a control center station with a computer, monitor, keyboard and supporting control and electrical equipment as illustrated in FIG.  3 . Furthermore, as shown in FIG. 1, one or more protective conduits  200  may be used to shield and house electrical cables and hydraulic lines which are used to control the robot&#39;s various modules. 
     The robotic container handling system  18  of the present invention is manufactured from readily available materials and simple in design. The preferred embodiment is comprised of metal, more particularly stainless steel, steel, or brass; however, it is contemplated that plastic or other polymer composite materials, such as graphite fiber, nylon, or even fiberglass, could be molded and used in combination with or substituted for the steel components of the present invention. 
     With reference to FIG. 1, the present invention comprises a high speed robotic parts handling system  10 , whereby movement of the parts handling system  10  in the X-axis is accomplished by moving a platform or base  19  supported by rollers  26  which roll on a pair of rails  28 . As best illustrated in FIGS. 1,  3 - 4 , and  54 , the pair of rails  28  include a first master rail  29  having a modified “I-beam configuration” including an “L-shaped member”  35  backed against a “C-shaped member” 37 . More particularly, the “L-shaped member” includes defining vertical body member connecting to a horizontal leg supported by a base defining the outside portion of the rail  29 . The interior portion of the master rail  29  includes a top arm extending inwardly connecting to a vertical body member supported by a horizontal leg mounted onto a base member thereby forming a channel. The minor rail  31  is a simple “I-beam”  31  provided only for stability. Of course, it is contemplated that the minor rail  31  could be replaced with another master rail  29  including magnets  30  for cooperatively engaging another linear servo motor  22  mounted to the opposing side of the platform  19 . 
     Moreover, the minor rail  31  could be eliminated and a single master rail  29  utilized for support of the platform, by for example, a “T”-shaped rail providing a vertical and horionzontal support surface for mounting the magnets thereto and supporting the requisite load bearing roller wheels and positioning rollers on the rail. 
     As shown in the Figures, a plurality of free wheeling rubber rollers  26  hold the platform  19  to the rails  28  shown in the figures. In the preferred embodiment six rubber rollers  26  are mounted along the sides of the platform  19  to roll on top of the rails  28  and two rollers  26  are mounted laterally to the platform providing lateral support thereto. The robot  10  and its payload are supported by anti-friction bearings. Furthermore, a plurality of positioning rollers or positioning rollers comprised of nonferrous material are used to maintain a constant distance between the faces of the linear servo motors  22  mounted onto the moving platform  19  and continuous magnet panels or plates  30  mounted to the master guide rail  29 . In the preferred embodiment, twelve positioning rollers  24  are mounted onto a longitudinal support member  13  having a generally square cross-sectional shape and which extends along one side of the base  19 . The positioning rollers or guide wheels  24  are used to separate and hold the linear servo motors  22  away from the magnets  30  positioned alone the master rail  29  a selected distance. As best shown in FIGS. 1,  4 ,  5 - 7 , and  54  the positioning rollers  24  contact the master rail  29  at points above and below the magnet plates  30  which are located therein between. The positioning rollers  24  have the hub and inner wheel portion fabricated from aluminum and an outer periphery band is fabricated from stainless steel; however, it is contemplated that other materials such as graphite, other polymers, or even ceramic material could be used to fabricate the nonferrous positioning rollers  24 . Using accurately sized positioning rollers  24  rolling upon the vertical sides of the master rail  29  provides a means for selecting and accurately maintaining a precise distance between the rail mounted magnets  30  and the linear servo motors  22  mounted to the platform  19  of the robot  10 . 
     The platform is powered by at least one and preferably a pair of brushless linear servo motors  22  and permanent magnets  30  mounted on edge to the side of the rail  28  whereby the faces of the motor(s)  22  and magnets  30  are perpendicular to the platform surface  19  and the supporting surface of the rails  28 . Thus, linear motor is mounted  22  vertically to the track rail  28  allowing for the use of a single master rail for both robot support and propulsion. 
     The linear motors  22  and magnets  30  provide a means to accelerate, propel, and stop the payload platform  19  at precise locations along the horizontal rail  28 . This high speed system is capable of speeds of to 1,000 feet per minute in the X-axis and subject to acceleration up to 0.6 g. 
     The rails  28  having a magnet bank  30  of permanent magnet plates extending therealong as shown in the FIGS. 4-8 and  54 . More particularly, the linear servo motors  22  are mounted in tandem for providing a magnetic positioning system whereby the platform  19  is suspended by a plurality of rail rollers  26  supported and guided upon rails  28 . A plurality of magnets  30  may be abutted together as longitudinal plates and affixed to the rail  28  depending upon the desired length of the track. In the preferred embodiment the magnets are attached to the outer vertical portion of the rail; however, it is contemplated that the magnets  30  could be affixed to the inside of the rail or a separate strip of longitudinal material in close proximity thereto. The thickness of the magnet plates is dependent upon the magnetic force required for the linear motor(s) selected, and the length and width of the magnetic plates  30 , but it is preferably less than one inch thick, more preferably less than one-half inch thick, and most preferably from about 0.35 to about 0.50 inches thick. As best shown in FIGS. 2 and 19, a gap  25  of approximately 0.020th of an inch gap exists between the motor  22  and the rail  28 . The strong attraction between the motor(s)  22  and magnets  30  allow the motors  22  (and platform  19 ) to follow a slightly irregular track path if required. Moreover, the unique arrangement allows clearing debris which could foul the running clearance necessary for motor efficiency. 
     A thin magnetic tape indicator strip  32  extends along the inner surface of at least one of the rails  28  includes magnetized graduations  36  which generate pulses readable by the a reader in communication with the control unit for the robot  10  as it moves along the rails  28 . 
     Movement is accomplished by interaction of the linear motors  22  with the magnets  30  based upon the Hall effect, whereby a transverse electric field is developed in a current-carrying conductor placed in a magnetic field. Ordinarily the conductor is positioned so that the magnetic field is perpendicular to the direction of current flow and the electric field is perpendicular to both. The high magnetic attraction between the coil assembly of the linear servo motors  22  and magnet plates is very effective for preloading heavy-duty bearings commonly used in high force applications such as the closed loop servo performance required for the instant invention. 
     As shown in FIGS. 10-11 and  54 - 55 , at least one fail safety brake  29  is attached to the platform  19  having a brake shoe  27  held in the “on” position by springs to bear against the inside one of more of the rails  28 , wherein the brake shoe  27  is spaced apart from the rail  28  and held in the release “open” position by air pressure supplied to the actuators of the robot  10 , so that failure of the air pressure permits the shoes to contact the guide rail  28  stopping the motion of the platform  19  in case of an emergency. 
     Movement along the Y-axis is accomplished by having at least one end effector assembly  12  mounted on a cross slide module  23  attached to a support saddle  56  pivotally mounted between a pair of trunions  53  suspended by a pair of slide members  52  cooperatively engaging a timing belt  62  reciprocating up and down vertical rails  46  mounted to a vertical column  44  extending upward from the platform  19  and being supported by an “A-frame”  40  mounted upon the platform  19 . More particularly, as illustrated in FIGS. 1,  4 - 5 ,  9 ,  12 - 15 , and  44 - 45 , the “A-frame” or frame  40  includes a pair of spaced apart vertical support columns  44  extending upward from the base  42 . Three vertical guide rails  46  are attached to and extend along each support column  44  on the sides and outer surfaces thereof. The support columns  44  are connected together at the top end by a horizontal truss member  48 . A plurality of twelve guide rollers  50  move in cooperative engagement along the surface of the frame guide rails  46  in the Y-axis. 
     The support column  44  having three guide rails  46  includes guide rolls  50  in cooperative communication therewith extending from the interior side of a pair of aluminum slide members  52 . The slide members  52  consist of a back and sides plates attached forming a “U-shaped” slide member  52 . The guide rolls  50  positioned on each side of the rail  46  slidably hold the slide member  52  to the guide rails  46 . The slide members  52  have a pair of trunions  53  projecting inwardly therefrom connecting to the distal ends of an end effector support saddle  56  which support one or more end effectors assemblies  12  which pick up, convey, position, and release the containers or cartridges  16 . The saddle  56  defines a substantially flat base having upwardly extending arms in cooperative engagement with the trunions  53  providing for movement in tilting the saddle  56  along the X-axis in the Y direction “side to side”, so the saddle is  56  higher with respect to one side of the vertical support columns  44  than the other and utilizing hydraulic, air cylinders, or ball screw actuator (electric cylinder)  51  for tilting the saddle  56  pivoting around the X-axis providing a means to cooperatively engage the upper containers of the mail sorting apparatus and providing a means for engaging the receiver  21  of the buffer  20  which are formed having a downward angle of about 10 degrees in order to hold the containers  16  in position by gravity during transfer from the receiving point to the distribution point. 
     A means for attaching a steel and KEVLAR reinforced urethane timing belt  60  having a plurality of spaced apart projections extending therefrom is attached to an exterior side of each of the slide members  52  and extends around a pulley  62  mounted to the top of a column  44  and driven by a motor  63  mounted to the bottom of the column  44  for moving the slide member along the vertical guide rails  46  at a high rate of speed. 
     At least one and preferably more end effectors  12  are mounted onto the platform  19  providing a means of elevating and maneuvering a container or cartridge thereon. FIG. 15 shows a top view of the guide rollers  50  mounted onto the saddle trunion  53  supporting the end effector  12  for sliding up and down the guide rails  46  mounted to the vertical support  44  of the frame  40  having a pair of opposing fail safe brake pads  27  extending against the interior surface of the support column to stop vertical motion of the assembly upon loss of power. 
     A fail safety brake  29  is also attached to each slide member  52  having a brake shoe  27  in the “on” position to bear against the inside of the support column  44 , wherein the brake shoe  27  is spaced apart from the guide rail  46  and held in the release “open” position by air pressure supplied to the actuators of the robot  10 , so that failure of the air pressure permits the shoes  27  to contact the column  44  stopping motion of the slide member  52  in the vertical direction in case of an emergency. 
     As best illustrated in FIGS. 16-23, each end effector conveyor  14  is supported by a cross slide module  23  mounted onto the saddle  56  normal thereto. At least one end effector assembly  12 , and preferably more than one end effector assembly  12  is mounted onto the cross slide module  23  supported by a saddle  56 . 
     The cross slide module  23  includes a cross slide base  65  having a pair of rods or rails  61  mounted thereon slidably engaging corresponding linear ball bearings  69  within which support a cross slide mounting platform  64 . The mounting platform  64  is moved back and forth with respect to the cross slide  23  in the Z-axis with respect to the platform  19  by means of a servo driven ball screw  66  enclosed within a rubber bellows  67  ending in a ball screw support bearing housing  61  and powered by a drive pulley  62  connected to a servo motor  63  by a belt  60 . 
     Mounted onto the cross slide module  23  of the end effector head assembly  12  perpendicular to the end effector support saddle  56  is at least one and preferably two or more conveyor modules  14  as shown best in FIGS. 24-29 for interfacing with the container (cartridges)  16 . Each conveyor module  14  includes a frame  57  mounted onto the cross slide module  23  which supports a pair of conveyor rails  59  having a drive end pulley  47  and distal end pulley  54 . A belt guide projection  55  is located in front of the drive end pulley  47  and pass the distal end pulleys  54 . A spring  71  attached to the rail  59  biases against the conveyor take up end axle  73  of the distal end pulley  54  to maintain selected tension on the conveyor belt  68 . The conveyor belts  68  are driven by a servo motor  74  through a timing belt reduction drive  76  which engages a first set of drive pulleys  47  which are connected by the belt  68  to the set of idler pulleys  54 . A polyethylene slide plate  82  which rests upon an aluminum frame rails  59  supported by the frame  57  mounted to the cross slide saddle  64 . A pair of conveyor belts  68  fabricated of steel and KEVLAR reinforced urethane are driven by a timing belt  75  in communication with the drive end pulleys  47  and a servo motor  74  mounted to the frame  57 . It is contemplated a single belt fabricated from different material could be substituted for the belt  68  of the preferred embodiment. Moreover, the conveyor belt  68  of the preferred embodiment includes a plurality of spatial profiles or cleats  70  extending or projecting therefrom for positive cooperative communication with corresponding indentations  72 , molded into the bottom of the container (cartridge)  16 . 
     As best shown in FIGS. 29-34, a drop gate actuator assembly  90  comprises a support frame member  92  generally centrally mounted onto the cross slide module  23  inbetween the conveyor belts  68  and near the distal end of the conveyor belts  68  for engaging the drop gate of the container (cartridge)  16  held within the storage cart or slot of the sorting apparatus  18 . The entire drop gate actuator assembly  90  extends above the cross slide module  23 , but below the conveyor belts  68  and the pass line of the container  16  passing thereover. 
     A drop gate actuator motor  91  is mounted onto a support frame member  92  mounted onto the cross slide module  23 . Extending from the servo motor  91  is a shaft having a pulley  93  mounted thereon. The pulley drives a first timing belt  106  extending upward to a first drop gate pulley  102  attached to the a drive shaft  94  held by the inward end of the support frame member  92  in alignment with the drive shaft  94 . A second drop gate pulley  104  of a lesser diameter, preferably ½ the diameter of the first drop gate pulley  102 , is attached to the shaft  94 . A first drop gate link arm  96  is rigidly mounted to the shaft  94  extending at a selected angle therefrom. A second drop gate top link arm  98  is pivotally connected to the distal end of the first drop gate link arm  96  by a shaft  97  allowing rotation thereof from 0 to 180 degrees providing the second drop gate top link arm  98  to extend in a straight line or pivot back upon the first drop gate link arm  96 . The shaft  97  controlling the movement of drop gate arm  98  is rotatably held by a portion of the frame  92  in alignment with shaft  94 . An upper drop link control pulley  103  extending from the inward end of shaft  97  is in cooperative engagement with the pulley  104  and driven by timing belt  106 . Rotation of the upper control link pulley  103  by rotation of the timing belt  166  rotates the drop gate top link  98  effectively raising or lowering the distal end  100  of the drop gate top link arm  98  allowing movement in a vertical straight line and in vertical alignment with the drive shaft  94 . The ability for the distal  100  of the second drop link top arm  98  to move vertically develops the straight line motion required for alignment and engagement of the drop gate  132  of the container (cartridge)  16 . The means for engagement of the drop gate  132 , as shown in the preferred embodiment, is a socket  107  having a notch  108  therein extending normal from the front end of the distal end portion  100  of the second top link arm  98 . A tension means such as a spring  105  retains the socket  107  so that the notch  108  is in vertical alignment for engagement of the drop gate rod  132  of the container  16 . 
     Moreover, as best shown in FIGS. 29 and 33, a cartridge drop gate spring depressor  99  having a head  101  with a concave surface  160  for cooperatively engaging the socket  107  of the drop gate in the down position extends from the distal end of a curved push arm  95 . The push arm  95  is supported by frame  92  and guided by cam rod bearing  162  and a pair of vee guide wheels  107 . The push arm  95  slides over a spring retainer  164  biased by spring  168  for working simultaneously with the drop gate  90 . The cartridge drop gate spring depressor  164  raises in unison with the drop gate socket  107  and releases drop gate  132  holding/retaining members on the bottom of the cartridge  16  upon engagement of the drop gate socket  107  with the drop gate  132 . 
     As best illustrated in FIGS. 36-43, a stack support actuator assembly  112  supported by a stack support base  114  is mounted upon the cross slide module  23  of the effector end  12 . The actuator defines a rack “rod”  116  and pinion  118  assembly whereby the horizontal member or rack  116  extends through a block stack support  109  having a stop block  113 . The rear end of the rack includes a carriage pull finger  170  front end of the rack  116  defines a “two prong” or “fork”  120  shape tool for cooperative engagement with a stack support  130  of a container “cartridge”  16 . The fork  120  a release plunger  172  disposed inbetween the tines and a downwardly angled lifting surface  115  providing a means to engage a container (cartridge)  16  within a slot of the mail sorting apparatus  18  and lift a stack support  130  vertically disengaging the stack support  130  from a rod forming a locking bar mechanism in the container  16 . 
     The stack support actuator assembly  112  is mounted to a support block  109  which is mounted by slide bars  111  in cooperative sliding engagement supported by a frame  110 . The frame  110  includes a roller plate  117  extending upwardly, spaced apart from, in alignment with, and opposite to, the support block  109 . At least one and preferably two sets of spaced apart vee guide rollers  119  extend inwardly in alignment with one another from the top and bottom of the roller plate  117 . A cam plate  123  having an “S-curve” track  121  is held between the vee guide rollers  119  of the roller plate  117 . The cam plate  123  is attached in the rear to a plunger  125  extending from a cylinder  127  mounted to a cylinder mount  129 . Extending from the support block  109  is a roller  131  which rolls along the cam plate track  121  providing forward lifting movement to the block  109  and stack support actuator assembly  112  mounted thereon upon actuation of the cylinder  127 . The cam mechanism provides good acceleration and declaration. For instance, a 2½ inch stroke lifts the fork  120  by about one inch. 
     The preferred embodiment of the container or cartridge  16  is formed of a plastic material; however, it is anticipated that metal or other material may utilized therefor. The container  16  of the preferred embodiment defines is formed having indentations on the bottom thereof for positive cooperative engagement with the conveyor belts  68  of the belt conveyor module  14  of the end effector assembly  12 . 
     As best shown in FIGS. 50-52, a clearing gate actuator  140  utilizes a cylinder  141  having a bumper  142  extending from a plunger to interface with a clearing gate of a mail sorter which sweeps the mail downward into the cartridge  16  compressing the mail slightly and moving it toward the stack support member  130 . Rollers  144  extending from a support flange  146  of the clearing gate actuator  140  aid in guiding the movement of the cartridge  16 . As the drop gate actuator  90  engages and pulls the peripheral rod  121  of the drop gate  132  down in the front of the cartridge  16 , the loops  135  pivot upward between the mail and sorter  18  holding the mail securely for movement by the end effector assembly  12  to a desired position. 
     An alternate embodiment of the present invention as shown in FIGS. 53 and 54 show the platform base  19  of the present invention incorporating the use of fail safe brakes  33  mounted to each end of the platform  19  for easy maintenance. FIG. 54 shows an end view and FIG. 55 a top view of the platform  19  is supported above the master rail by a longitudinal member  13  to which is mounted the linear servo motor  22 , the magnets  30 , the nonferrous positioning rollers  24  with the antifriction bearings therein, the rubber support rollers  26 , and the brake pads  27  of the fail safe brake  33  in contact with the vertical sidewalls of the master rail  29 . 
     The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modifications will become obvious to those skilled in the art based upon more recent disclosures and may be made without departing from the spirit of the invention and scope of the appended claims.