Abstract:
A device for and method of robotically crating objects, such as consumer goods, being capable of securing an upstanding enclosure to a recyclable pallet having structural uprights. The device conveys a pallet and enclosure assembly into a work station, installs a number of threaded fasteners into predetermined locations in the top and two adjacent sides of the assembly, rotates the assembly one-hundred eighty degrees, installs fasteners into the two remaining sides, rotates the assembly back to the initial position, and conveys the secured crate assembly out of the work station. The device includes the ability to detect the number of times a recyclable pallet has been used, and to adjust the exact locations of fasteners accordingly, thereby assuring that new fasteners are always installed into an unused fastener location.

Description:
RELATED APPLICATION  
       [0001]    This application is a division of co-pending U.S. application Ser. No. 09/670,202, filed Sep. 25, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates generally to the field of crating and palletizing objects, such as consumer goods, in shipping boxes, and specifically to a device capable of securing an upstanding crate to a recyclable pallet having structural uprights.  
           [0003]    Near the end of a manufacturing conveyor line, finished product is often secured to pallets and crated for shipping. U.S. Pat. No. 5,823,349 describes a shipping container comprising a wooden base, a corrugated cardboard box that fits over the base, reinforcing material applied to the box adjacent to the base, and a plurality of fasteners which fasten the box to the base through the reinforcing material. While the described invention is a good system for attaching a cardboard crate to a wooden base, it provides little structural integrity and may collapse under a moderate overhead load. Shipping containers are typically stacked and sometimes require a high degree of structural rigidity. The present invention makes use of highly rigid structural uprights attached to the pallet which help support loads from all sides, as well as provide for additional fastener locations.  
           [0004]    Traditionally, the task of securing the product and crate enclosure to the pallet has been carried out manually. The repeated motions of manual labor can become tedious, and depending on the size of the crates, such tasks can also become strenuous. Continued crating and moving of such containers can cause injury to workers. Further, depending on the output speed and configuration of the conveyor line, multiple workers may be required to properly palletize and crate the product. In an effort to reduce workforce size and injury costs, there has been a significant move toward automating this process by utilizing robots. As is known in the art, industrial robots may be fitted with various “end of arm tools” or “end-effectors” to accomplish different tasks, including driving fasteners into a connecting medium.  
           [0005]    Robots have some advantages over human workers, such as being able to work continuously for days or weeks, while at the same time virtually eliminating human error. However, robotic arms lack the mobility of a human workforce. Due to a limited range of motion, a typical robot can only reach one or two sides of a container. Multiple robots have been needed to secure fasteners in all required locations. The present invention employs a turntable that rotates the container, thereby allowing a single robot to complete the entire task.  
           [0006]    After the enclosure is properly fastened to the pallet, the container is ready for shipping. When it reaches the “point of sale and delivery” destination, the pallet and enclosure are usually discarded. In the case of a distributor or retailer who receives a high volume of product, the vast amount of shipping materials creates disposal problems. Some dealers have even turned to burning the combustible materials because of the resources required to store and ship away the large amounts of refuse.  
           [0007]    Disposing of the shipping materials can also be very wasteful. The pallet is usually well built to provide a stable platform for supporting the product and moving the container. Some large or heavy products make use of a metal pallet, which are more difficult to dispose of than those made of wood. Metal pallets are relatively more expensive than other shipping materials, and should be used multiple times to boost efficiency.  
           [0008]    Reusing the shipping pallets requires some regulation to ensure they are still capable of providing an adequate supporting platform and secure fastening surface. The present invention employs a method of identifying said pallets before use in a way that allows the device to physically detect whether the pallet is still usable.  
         SUMMARY OF THE INVENTION  
         [0009]    According to the present invention, the foregoing and other objects and advantages are attained by providing an apparatus or device capable of conveying a pallet and enclosure assembly into a work station, detecting if the pallet is usable, installing a number of fasteners in predetermined locations, and conveying the finished container out of the work station.  
           [0010]    The process begins by manually securing a product to the pallet. This can be done in one or more ways, such as attaching straps to the pallet that wrap around said product. Next, one or more rigid U-shaped uprights are inverted and placed into pre-existing slots in the pallet. A bottomless cardboard enclosure is then lowered over the pallet, enclosing said product and said uprights.  
           [0011]    The entire pre-loaded crate assembly may be brought to the work station by an infeed conveyor. The conveyor has pallet usage sensors that recognize how many times the current pallet has been used before, and photoeye sensors that detect the physical size of the incoming crate. This information is sent to the robot&#39;s computer for calibration of the fastening sequence.  
           [0012]    The pre-loaded container is delivered by an infeed conveyor to a turntable, where it is rotationally aligned to receive fasteners. The robot end-effector is equipped with at least one automatic screwdriver that receives threaded fasteners from a feeder mechanism. The preprogrammed robot and its screwdriver install said fasteners through the cardboard crate into the pallet and rigid uprights.  
           [0013]    Because the robot has a limited range of motion, fastener installation is preferably accomplished in stages. The robot first inserts fasteners through the top of the crate into the rigid upright(s), then inserts fasteners on two adjacent sides of the container, into either the upright(s) or the pallet, depending on the preselected fastener location. The turntable then rotates the container 180° so the robot can install fasteners into the two remaining sides. When this stage of robot activity is completed, the turntable reverses back to its original position. A conveyor then moves the finished container off the turntable and onto an exit conveyor. If any faults had been detected during the robot&#39;s fastening operation, a label is placed onto the container as it leaves the work station indicating that a manual inspection and correction is required. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of the present invention.  
         [0015]    [0015]FIG. 2 is a top plan view of the present invention.  
         [0016]    [0016]FIG. 3 is a perspective view of the present crate assembly.  
         [0017]    [0017]FIG. 4 is an exploded view of the present crate assembly.  
         [0018]    [0018]FIG. 5 is a perspective view of the present crate assembly with all components visible.  
         [0019]    [0019]FIG. 6 is a perspective view depicting the present invention as the crate assembly enters the work area.  
         [0020]    [0020]FIG. 7 is an elevational side view depicting the robot and fastener supply system.  
         [0021]    [0021]FIG. 8 is a side elevational view depicting the robotic end-effector of the present invention.  
         [0022]    [0022]FIGS. 9 through 12 are perspective views depicting the present invention during various stages of operation.  
         [0023]    [0023]FIG. 13 is a top plan view of the turntable assembly.  
         [0024]    [0024]FIG. 14 is a front elevational view of the turntable assembly.  
         [0025]    [0025]FIGS. 15 through 19 are perspective views depicting the present invention during various stages of operation.  
         [0026]    [0026]FIGS. 20 and 21 are side elevational views of the turntable assembly depicting the crate assembly being conveyed off the turntable.  
         [0027]    [0027]FIG. 22 depicts a side view of the label applicator of the present invention.  
         [0028]    [0028]FIG. 23 depicts a top view label applicator of the present invention.  
         [0029]    [0029]FIG. 24 is a perspective view of the pallet from slightly above.  
         [0030]    [0030]FIG. 25 is a perspective view of the pallet inverted to show the bottom thereof.  
         [0031]    [0031]FIG. 26 is a cross-sectional view showing the pallet usage identification sensors, taken along line  26 - 26  of FIG. 2.  
         [0032]    [0032]FIG. 27 is a side elevational view showing the pallet usage identification sensors.  
         [0033]    [0033]FIG. 28 depicts the arrangement of available fastener locations in a fastening zone of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0034]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.  
         [0035]    With reference to FIGS.  1 - 3 , inclusive, the present invention comprises a robotic crate fastening cell  30  for crating and palletizing objects. In brief, the apparatus includes a pre-loaded crate assembly  80 , an infeed conveyor  50 , a turntable  60 , a robot  40 , a robot control system  42 , and an exit conveyor  70 . A conventional programmable logic controller (PLC) or similar device controls the operation, receiving information from and giving instructions to the various components in the correct order.  
         [0036]    The crate assembly  80  is fed onto the turntable  60  by the infeed conveyor  50 . A plurality of fasteners are installed into the top  92 , a first end  93  and first side  94  of the crate assembly  80  by the robot  40 . The crate assembly  80  is then rotated 180 degrees around its central vertical axis by the turntable  60 . A plurality of fasteners are installed into second end  95  and second side  96  of the crate  80 . The turntable  60  then rotates the crate  80  back to the original position, and the crate assembly  80  exits the cell  30  via the exit conveyor  70 .  
         [0037]    [0037]FIG. 3 depicts a typical crate assembly  80  and shows one example of fastener locations. Of the twenty-eight total locations in this particular configuration, sixteen are visible in FIG. 3, specifically, four in the top  92  (F 1   a,  F 1   b,  F 2   a,  F 2   b ), two in the first end  93  (F 3 , F 4 ) and ten in the first side  94  (F 5   a,  F 5   b,  F 6   a,  F 6   b,  F 7   a,  F 7   b,  F 8   a,  F 8   b,  F 9   a , F 9   b ). Two more (locations F 10  and F 11  being shown in FIG. 17) are located in the second end  95 , while ten more (locations F 12   a -F 16   b,  inclusive, being shown in FIG. 18) are located in the second side  96 . Individual fastener locations, such as “F 1   a ,” identified in FIG. 3 will be referred to later in this description. Fastener location terminology will also be described below.  
         [0038]    Now referring to FIGS. 4 and 5, the crate assembly  80  comprises an object  83  to be crated, a pallet base  81 , one or more structural uprights  82 , and an enclosure or container  87 . The object  83  is placed on the supporting platform  99  of the pallet base  81  and secured to prevent shifting. The present method of securement includes tying down the object  83  using straps  91  affixed to eyelet holes  85  in the pallet base  81 . Structural uprights  82  are then placed into receiving slots  90  in the pallet base  81 . The structural uprights  82  will eventually provide vertical support to allow stacking of finished crate assemblies during shipping. The enclosure  87  is lowered over the uprights  82 , object  83  and pallet base  81  to form the crate assembly  80 . A marginal fastening area  97  of the enclosure  87  overlays a fastening surface  78  of the pallet base  81 . A plurality of handgrip openings  88  may be formed in the enclosure  87 , and may be placed to allow manual or visual confirmation that the structural uprights  82  are correctly in position. Lift openings  86  in the pallet base  81  and enclosure slotted end portions  89  allow the crate assembly  80  to be carried by a conventional forklift vehicle to and from the robotic cell  30 .  
         [0039]    The pre-loaded crate assembly  80  may be brought manually or via forklift to the infeed conveyor  50 , and set on an incoming storage conveyor  38 , as shown in FIG. 1. A plurality of infeed rollers  51  begin rotation, thereby conveying the crate assembly  80  until it rests against a popup stop  52  at the location depicted by FIG. 6. The crate assembly  80  is then checked for both physical size and previous usage of the pallet base  81 . This information is electronically transmitted to the robot control system  42 , and is used to calibrate the robot  40  for the immediate crate assembly  80 , as the present invention is capable of operating on crate assemblies of various sizes, and of reusing pallet bases  81  a predetermined number of times. One or more photoeye sensors  58  (see FIG. 1) determine the physical height and length of the crate assembly  80 , while the pallet usage sensor  54  determines the number of times that the pallet base  81  has been previously used. Operation of the pallet usage sensor  54  and the effects of its findings will hereinafter be discussed.  
         [0040]    Once the needed information is ascertained, the popup stop  52  is retracted and the infeed rollers  51  and turntable rollers  62  convey the crate assembly  80  onto the turntable  60 . When the crate assembly  80  clears the popup stop  52 , the infeed rollers  51  stop and the popup stop  52  returns to its original position. The crate assembly  80  is moved until it rests against a fixed stop  63  (see FIG. 6) on the turntable  60 , wherein the turntable rollers  62  shut off. The crate assembly  80  is now in position to receive fasteners from the robot  40 .  
         [0041]    With specific reference to FIGS. 7 and 8, in the preferred embodiment, the robot  40  comprises a six-axis robot arm  41  equipped with an end-effector  44  having one or more pneumatic screwdrivers  45 , each screwdriver  45  being arranged to receive threaded fasteners  36  from a vibratory bowl feeder system  46 . In the present embodiment, the end-effector includes two Weber screwdrivers, each having its own SureTork controller  43  and vibratory bowl feeder system  46 . Threaded fasteners  36  are stored in vibratory feeder bowls  47  and are released from an air-operated escapement  48 . The fasteners  36  are conveyed by air pressure through a feed tube  49  and delivered into the end-effector  44 . As the fasteners  36  are installed into the crate assembly  80 , the SureTork controllers  43  monitor the torque applied to each fastener and the degrees of rotation of each fastener. If the fastener torque does not reach a certain minimum, or if the number of rotational degrees recorded is too high or too low, a fastener failure is detected and, upon ejection from the robotic cell, the crate assembly  80  will be labeled for inspection.  
         [0042]    In our preferred embodiment, the robot is an IRB6400/2.3-120 model manufactured by ABB of Sweden. The preferred pneumatic screwdrivers are commonly referred to as Weber screwdrivers and are manufactured by Weber Screwdriver of Kisco, N.Y.  
         [0043]    As depicted in FIG. 9, the robot  40  begins fastener installation by installing four fasteners  36  through the top  92  of the crate assembly  80  and into the top rail of the structural uprights  82 . Because the preferred end-effector  44  has two screwdrivers  45 , the robot need only stop in two positions, installing two fasteners simultaneously at each position. It should be apparent that one or multiple end-effector tools may be used without departing from the present invention. Multiple robots  40  could also be employed.  
         [0044]    Herein, fastener locations will be identified by the letter “F,” followed by a number that corresponds to the stop position of the robot while installing those fasteners. The stop position number may range from 1 to 16, as there are a total of sixteen robot stop positions in which fasteners are installed. This designation may be followed by reference letters “a” or “b” to identify between the two possible fastener locations at each robot stop position.  
         [0045]    The robot  40  stops at its first position and installs fasteners F 1   a  and F 1   b  through the enclosure  87  and into a structural upright  82 . The robot  40  then moves to a second position (as depicted in FIG. 9) and drives fasteners F 2   a  and F 2   b  through the enclosure  87  and into the other structural upright  82 .  
         [0046]    Next, referring to FIGS. 10 and 11, stabilization clamps  65  are actuated, thereby clamping the crate assembly  80  against the stabilization bar  64 , supporting the crate assembly  80  against the pressure of fastener insertion and preventing the crate assembly  80  from being skewed horizontally. The robot positions along the first end  93  of the crate assembly  80  and installs a single fastener F 3  through the enclosure  87  and into the pallet base  81 , as depicted in FIG. 10. A single fastener is used at this stop position because there is no rigid fastening surface behind the enclosure  87  above the pallet base  81 . Next, the robot  40  moves a short lateral distance to the fourth stop position and installs fastener F 4  on the first end  93  of the crate. It is conceivable, and within the purview of the invention, that fasteners F 3  and F 4  could be installed simultaneously using the preferred end-effector  44 . However, fasteners F 3  and F 4  may not be installed simultaneously if, as in the present case, the distance between the two fastener locations differs from the distance between the two screwdrivers  45  on the end-effector  44 .  
         [0047]    The robot  40  next swings around to the first side  94  of the crate assembly and into a fifth stop position, and installs fasteners F 5   a  and F 5   b,  both of which pierce the enclosure  87  and pallet base  81 . Fastener F 5   a  also passes through a structural upright  82 , thereby securing the upright  82  to the pallet base  81 .  
         [0048]    [0048]FIG. 11 depicts the robot  40  in the sixth position, installing fasteners F 6   a  and F 6   b  through the enclosure  87  and into the pallet base  81 . The robot then moves farther down the first side  94  of the crate assembly  80  and installs fasteners F 7   a  and F 7   b  in similar fashion, with fastener F 7   b  passing through a structural upright  82 . Reference to FIG. 3 may be helpful for showing the locations of these fasteners.  
         [0049]    With reference to FIG. 12, the robot  40  now rotates the end-effector  44  ninety degrees, placing the two screwdrivers vertically relative to one another. At the eighth position, fasteners F 8   a  and F 8   b  are driven into the upper half of the first side  94 , through the enclosure  87  and into one structural upright  82 . Fasteners F 9   a  and F 9   b  are installed in similar positions into the other upright  82 . Again, FIG. 3 may be a useful reference for location of the fasteners. The robot  40  is now finished installing fasteners into the top  92 , first end  93  and first side  94  of the crate assembly  80 , and moves clear of the turntable  60 .  
         [0050]    The turntable  60 , which supports the crate assembly  80 , is depicted in FIGS. 13 and 14. Rotation is accomplished by a single drive wheel  68  set in a stationary track  69 . As the wheel  68  turns, the upper portion of the turntable  60  rotates about a central pivot point  67 . FIGS. 13 and 14 also depict the stabilization clamps  65  and an actuator  75  attached to each. As the actuator  75  extends or retracts, the stabilization clamp  65  raises or lowers. A lift chain conveyor  61  is also shown, and is later used to convey the crate assembly  80  off of the turntable  60 . In our preferred embodiment, the turntable  60  is manufactured by Lauyans &amp; Company of Louisville, Ky.  
         [0051]    [0051]FIG. 15 depicts the robot  80  in a clear position and the turntable  60  rotated to allow installation of the remaining fasteners into the second end  95  and second side  96  of the crate assembly  80 . The robot installs fasteners F 10  and F 11  into the second end  95  in the same manner as fasteners F 3  and F 4  into the first end (see FIG. 16, showing the robot  40  in the eleventh stop position).  
         [0052]    The robot then moves to a twelfth stop position, along the second side  96  of the crate assembly  80 , and installs fasteners F 12   a  and F 12   b  into the pallet base  81 , with fastener F 12   a  passing through a structural upright  82 . The robot moves to a thirteenth position, as shown in FIG. 17, and installs fasteners F 13   a  and F 13   b . Fastener installation continues at the fourteenth, fifteenth and sixteenth stop positions, which correspond with stop positions seven, eight and nine on the first side  94  of the crate assembly  80 . FIG. 18 depicts the robot  40  at the sixteenth stop position installing fasteners F 16   a  and F 16   b.  After the these fasteners are installed, a total of twenty-eight fasteners have been driven through the enclosure  87  and into either the pallet base  81 , structural uprights  82 , or both. The crate assembly  80  is now complete. The robot  40  again moves to a clear position, as illustrated in FIG. 19, and the turntable  60  rotates in the reverse direction, returning the crate assembly to its initial position.  
         [0053]    [0053]FIGS. 20 and 21 depict the crate assembly  80  being conveyed off of the turntable  60 . The stabilization clamps  65  swing down and the crate  80  is lifted off the turntable  60  by the lift chain conveyor  61 . The lift chain conveyor  61  is a powered chain transfer unit that uses an air-operated lift mechanism. The entire lift chain conveyor  61  raises, lifting the crate assembly  80  off the turntable  60 . A belt chain  76  that rotates in a continuous loop conveys the crate assembly  80  laterally until it rests on the exit conveyor  70 . Crate assemblies  80  move down the exit conveyer  70  by gravity, and are positioned laterally to allow a greater number of crates to be stored on the exit conveyor before removal.  
         [0054]    As shown in FIGS. 1 and 2, a label applicator  72  is located on the exit conveyor  70 . If a fastener failure was detected during the fastening operation, a label is applied to the exiting crate  80  to signal the need for a manual inspection and correction. In the present embodiment, the label applicator  72  is a Universal L 60 . FIGS. 22 and 23 depict the present label applicator  72  in greater detail. The preferred label applicator  72  is manufactured by Universal Labeling Systems, Inc., of St. Petersburg, Fla.  
         [0055]    The crate  80 , with the supported object  83 , leaves the robotic cell  30  ready for shipping. The multi-functional structural uprights  82  allow multiple crates  80  to be stacked without damage to the product. When the crate  80  and supported object  83  arrive at the “point of sale or delivery” destination, the fasteners  36  are preferably removed and the enclosure  87  and uprights  82  discarded. It should be noted that only a minimum number of fasteners  36  need be removed in order to uncrate the object  83 . The pallet base  81  can return to the factory and be reused.  
         [0056]    With particular reference to FIGS. 24 and 25, the preferred pallet base  81  and structural uprights  82  are depicted. A predetermined number of usage indicators  84 , which may be formed on the pallet base  81  (see FIG. 25), correspond to the number of times the pallet base  81  may be used in a crate assembly  80  before it must be discarded. In the preferred embodiment, each usage indicator  84  is a predetermined location for an eventual use indication aperture  284  in the pallet base  81 . Use indication apertures  284  are physically probed by the pallet usage sensor  54  on the infeed conveyor  50 .  
         [0057]    A new pallet base  81  comes with only one use indication aperture  284  formed therein. After it is used in a crate assembly  80 , a second use indication aperture  284  is formed before the pallet base  81  is reused. In the present embodiment, there are ten possible usage indicators  84 , which correspond to the ten times the present pallet base  81  may be used. The present embodiment also uses pilot holes  184 , which are preformed into each usage indicator  84  location. The pilot holes  184  are small enough so as not to be detected by the pallet usage sensor  54 . They are used to ensure proper placement of the use indication holes  284 , which may be cut manually with a hole-cutting drill bit, or other suitable tool.  
         [0058]    With particular reference to FIGS. 26 and 27, the pallet usage sensor  54  comprises a plurality of spring-loaded probes  55 , each having a proximity switch  56  and air-operated popup mechanism  57 . The pallet usage sensor  54  is spaced a known distance from the infeed popup stop  52 . When the crate assembly  80  is in place behind the infeed popup stop  52 , the probes  55  align with the usage indicators  84  in the pallet base  81 . The probes  55  attempt to pop up, and either pass through a usage indicator aperture  284  or are prevented by the absence of such an opening (pilot holes  184  are physically smaller than the probes  55 , and do not allow passage). The proximity switches  56  sense the position of each probe and relay that information to the robot control system  42  for calibration of the robot  40 .  
         [0059]    When a pallet base  81  is reused in a crate assembly  80 , the new fasteners  36  in the pallet base  81  must be installed in slightly different locations than any previous fasteners. A previous fastener hole may not hold the new fastener securely, or old fasteners may have been left in the pallet base  81 . For this reason, every previously mentioned fastener location in the pallet base  81  (F 3 -F 7 , F 10 -F 14 ) is actually a zone comprising a plurality of possible pinpoint locations. In the present embodiment, a pattern of eleven possible pinpoint locations is available for each fastener in the pallet base  81 . This pattern in a single fastening zone  98  is depicted by FIG. 28. Fasteners installed into the structural uprights  82  that do not penetrate the pallet base  81  may always be installed into the same position because new uprights  82  are used in every crate assembly  80 . In other words, the fastening zone  98  exists primarily for fasteners installed into the pallet base  81 .  
         [0060]    A new pallet base  81  has one use indication aperture  284 . When the pallet usage sensor  54  determines that only one hole exists, the robot  40  is calibrated to install fasteners into the first pinpoint location P 1  in the fastening zone  98 . If the pallet usage sensor  54  determines that two use indication apertures  284  exist, it is known that the first pinpoint location P 1  has been previously used, and the robot  40  is calibrated to install fasteners into the second pinpoint location P 2 . This will continue until ten use indication apertures  284  exist, wherein the robot  40  installs fasteners into the tenth pinpoint location P 10 , and after which the pallet base  81  is discarded.  
         [0061]    The eleventh pinpoint location P 11  is provided as a backup location in case of fastener failure, and is available for a single use over the life of the pallet base  81 . If a fastener failure is detected, the robot  40  will attempt to place an alternate fastener  36  in pinpoint location eleven and manual inspection will not be needed. Because the eleventh pinpoint location P 11  is only available for one use, an attempt to install a fastener into an eleventh location that has been previously used will result in a fastener failure, and the crate assembly  80  will be labeled for manual inspection.  
         [0062]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.