Abstract:
An auto reject unit includes a turntable rotatable about an upright axis and held stationary in operation along the upright axis. Driven rollers are mounted upon the turntable for selectively driving an article across the turntable in a direction. A motor is disposed to rotate the turntable about the upright axis in response to a command. The rotation adjusts the direction that an article disposed on the turntable will travel off of the turntable.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a sorting apparatus for sorting articles, such as items of baggage, on a conveyor. 
     X-ray systems for monitoring baggage are frequently installed in airports, government buildings and other places where security is important. 
     Such systems traditionally comprise a conveyor belt which passes through an X-ray scanner under the control of an operator. Baggage to be checked is loaded onto the conveyor belt, and passes into the X-ray scanner. Here, the baggage is irradiated with X-rays and a screen associated with the scanner shows the contents of the baggage to the operator. 
     The baggage passes out the other side of the scanner on the moving conveyor belt, and onto a set of freely rotatable rollers, called “lazy rollers”, adjacent to the conveyor belt. These rollers are typically mounted on a slight downward slope, so that the baggage is carried away from the moving conveyor belt. The baggage comes to rest in a collection area at the downward end of the rollers. 
     If the operator notes something suspicious in an item of baggage as it passes through the scanner on the conveyor belt, then the belt may be stopped whilst the item is still in the scanner. This permits the resultant stationary image on the screen to be inspected more closely. 
     If the operator then decides that the item must be investigated manually, an alarm is raised. This prompts another person to remove the item from the belt to a separate search area for opening and searching. Alternatively, random manual double-checks may be carried out on every one in ten, for example, items of baggage that are X-rayed. 
     In most situations it is important that the rate of examination of the baggage is as high as possible, to avoid delays. Clearly, items of baggage identified from manual inspection cannot be inspected in the collection area, as this will impede the retrieval of items of baggage which do not need to be manually inspected. Therefore, when an item has been identified for manual inspection, it must be lifted off the collection area (at the downward end of the rollers), and carried to a separate table. In order to maximize baggage throughput with this system, three operating personnel are therefore required, one to view the screen and identify items of baggage for manual inspection, one to remove such items from the collection area and place them on a separate table, and one to open the items on that table and manually search them. The weight of some items of baggage can create a health and safety problem for the person who is required to lift and carry such items from the collection area to the separate table. 
     In an alternative arrangement, a continuously moving conveyor belt has a chute arranged perpendicular to the belt. An extendable arm is located opposite the chute on the other side of the belt. When an object such as an item of baggage is identified to be removed from the belt, the arm extends rapidly transverse to the belt, pushing the chosen item down the chute. The arm then retracts back again. 
     The belt may move more rapidly in this alternative arrangement, thereby permitting a much more rapid rate of examination of baggage. However, the arm must equally extend and retract relatively rapidly, in order to avoid accidentally knocking adjacent bags as they move along the conveyor belt. The rapid reciprocating movement of the arm creates a substantial impulse on an item of baggage. Thus, the latter arrangement is wholly unsuitable for open or non-rigid baggage. 
     It is an object of the present invention to alleviate these problems with the prior art. 
     SUMMARY OF THE INVENTION 
     These and many other objects and advantages of the present invention will become apparent to those of ordinary skill in the art from a consideration of the drawings and ensuing description of the invention. 
     According to a first aspect of the present invention, there is provided an apparatus comprising: 
     a turntable; 
     driving means for selectively driving an article across the turntable; 
     and a motor arranged to rotate the turntable in response to a command, such that the article may be driven off the turntable by the driving means in one of a plurality of chosen directions. 
     The articles may thus be sorted into a plurality of directions, and moved off the turntable for instance into separate channels or onto separate platforms arranged adjacent the turntable in the various chosen directions. No manual input is required. 
     Preferably, the driving means includes at least one driven roller, and most preferably a plurality of driven rollers, mounted upon the turntable. 
     Preferably, the apparatus is controlled by a controller for receiving the command and sending a start motor signal to the motor to cause said motor to rotate the turntable. For example, the command may be user input in response to a particular property of the article, such as its contents, which may in turn be determined by X-ray examination of the articles. 
     The controller may also send a stop driving means signal to the driving means to stop said driving means as the turntable rotates. This prevents the article on the turntable from being ejected whilst the latter rotates. 
     According to a second aspect of the present invention, there is provided an apparatus for sorting baggage, comprising: 
     a conveyor for conveying baggage from a first end to a second end thereof; 
     a turntable, arranged adjacent the second end of the conveyor to receive the baggage therefrom; 
     driving means for driving the baggage across the turntable; and 
     a motor for rotating the turntable between first and second angular positions in response to a command, such that the baggage may either be moved off the turntable by the driving means and onto a first member arranged in the first angular direction or off the turntable by the driving means and onto a second member in the second angular direction. 
     Baggage which does not need to be manually inspected, for example, is moved onto a first member, such as a first bench, from where the baggage can be collected by its owner. Baggage which is to be opened and searched, for example will however be moved onto a second member, such as a second bench, suitably perpendicular to the first member. No lifting and carrying of the baggage is necessary which reduces the number of apparatus operators necessary and also reduces health and safety risks. 
     The invention also extends to a method of sorting articles comprising: 
     conveying a plurality of articles to a turntable; 
     and separating the plurality of articles by conveying a first quantity of articles to a first member through rotation of the turntable through a first angle, and driving each article onto the said first member, and by conveying a second plurality of articles to a second member through rotation of the turntable through a second angle, and driving each article onto the said second member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be put into practice in a number of ways, one of which will now be described with reference to the following Figures, in which: 
     FIG. 1 shows a plan view of one embodiment of the present invention; 
     FIG. 2 shows a side view of the embodiment of FIG. 1; 
     FIG. 3 shows a close-up plan view of a part of the embodiment of FIGS. 1 and 2; 
     FIG. 4 shows a sectional view through the line A-A′ in FIG. 1; 
     FIG. 5 shows a sectional view through the line B-B′ in FIG. 1; and 
     FIG. 6 shows a block diagram of the circuitry to control the embodiment of the invention shown in FIGS. 1 to  5 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Those of ordinary skill in the art will realize that the following description of the present invention is not intended to be in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons from an examination of the within disclosure. 
     Referring first to FIGS. 1 and 2, a baggage X-ray system  10 , including an automatic baggage handler, is shown. The system  10  includes an input unit  20  at a first end of a conveyor belt system shown generally at  30 . The input unit receives items of baggage to be X-rayed. 
     The conveyor belt system comprises a first conveyor belt  40 , and a second conveyor belt  50 . The first conveyor belt  40  is selectively arrestable, as will be described below, and thus acts to queue items of baggage placed in the input unit  20  onto the second conveyor belt  50 . This permits items of baggage to be moved onto the second conveyor belt  50  with a predetermined space between them, regardless of how closely packed the items of baggage are on the first conveyor belt  40 . 
     The system also includes two baggage guides  60 , which are mounted upon a frame (not shown) adjacent to the first conveyor belt. As may be seen from FIG. 2, these baggage guides  60  are generally conical and are freely rotatable about a vertical axis. Thus, the baggage guides  60  force items of baggage into the centre of the conveyor belt system  30  regardless of where in the input unit the items are placed. 
     A first item of baggage is carried along the first conveyor belt  40  and onto the second conveyor belt  50 . The second conveyor belt  50  in turn carries the item of baggage into an X-ray unit  70 , to which is connected a screen  80 . As the first item of baggage passes through the X-ray unit  70 , an image of the contents of the item of baggage is displayed upon the screen  80 . 
     The Civil Aviation Authority Guidelines of the United Kingdom for example require each item of baggage to be monitored for at least five seconds. Thus, the first conveyor belt  40  is arranged to queue the baggage onto the second conveyor belt  50  with a sufficient gap between each item. Furthermore, the second conveyor belt  50  is, like the first conveyor belt  40 , selectively arrestable. If the contents of the item of baggage are deemed acceptable to a person monitoring the screen  80 , then the second conveyor belt is allowed to continue moving. If, however, the contents of the first item of baggage are considered by the person monitoring the screen  80  to be suspicious, then the second conveyor belt  50  may be stopped whilst that item of baggage is still within the X-ray unit  70 . This allows the contents of the first item of baggage to be studied more closely on the screen  80 . 
     Once further investigation on the screen  80  has been completed, the second conveyor belt  50  may be restarted. Thus, the first item of baggage exits the X-ray unit  70 , still moving right-to-left as seen in FIGS. 1 and 2. 
     Meanwhile, further items of baggage are queued onto the second conveyor belt  50  from the first conveyor belt  40 . The first conveyor belt  40  is thus continually started and stopped to provide adequate spacing between items of baggage on the second conveyor belt  50 . Although this can be done manually, it is preferable to automate baggage queueing, and the way in which this is done will be explained below. 
     If an item of baggage is considered not to require further, manual investigation, then this item passes along to the end of the second conveyor belt  50  and onto a turntable  140 . In a first position, the item of baggage is driven across the surface of the turntable, in a direction parallel to its direction of travel along the conveyor belt system  30 . The item then proceeds onto a set of collection bench rollers  160  adjacent to the turntable  140 . The collection bench rollers  160  are motor-driven and thus drive the item of baggage onto a collection bench  170 . The collection bench  170  has a series of freely rotatable or “lazy” rollers (not shown for clarity), and the momentum imparted to the item of baggage by the collection bench rollers forces the item into a collection area  180  at the end of the collection bench  170 . 
     If the person monitoring the screen  80  considers that an item of baggage does require further, manual investigation, then that person operates an alarm. The alarm includes a klaxon or warning light, which indicates to another person employed to operate the system  10  that an item of baggage must shortly be manually searched. The item continues along the second conveyor belt  50  and onto the turntable  140 . The turntable rotates through 90° and drives the item of baggage onto a set of inspection bench rollers  190 . The inspection bench rollers  190  are located adjacent to the turntable  140 , at a first end of an inspection bench  200 . The inspection bench  200  is arranged perpendicular to the direction of travel of the conveyor belt system  30 , as may be seen from FIG.  1 . 
     The inspection bench  200  also contains a series of “lazy” rollers (again not shown for clarity) which allow the item of baggage to slide along the inspection bench and into an inspection area  210 . Here, the item of baggage may be opened and inspected manually. 
     Once the item of baggage to be inspected manually has been deposited onto the inspection bench  200 , the turntable  140  rotates back through 90° to allow subsequent baggage to be collected from the second conveyor belt  50 . If the next item of baggage does not need to be manually inspected, then it is passed to the collection bench rollers  160 , as previously described. If however the next item of baggage also needs to be manually inspected, then the turntable rotates through 90° once more to deposit the item onto the inspection bench  200 . 
     Thus, it may be seen that, once baggage has been placed into the input unit  20  at the end of the first conveyor belt  40 , no further lifting and carrying is necessary until each item of baggage has been X-rayed and manually inspected if necessary. This reduces health and safety risks, and also reduces the number of personnel required to operate the system  10 . Indeed, as the inspection area  210  is arranged proximal to the screen  80 , one person can operate the whole system  10  without introducing unacceptable delays. Normally, however, two people would be employed, one to monitor the screen  80  and one manually to inspect items of baggage as required. 
     Having briefly described the principles of the system  10 , the turntable and the manner in which it is controlled will now be described in more detail, with reference to FIGS. 3 to  6 . 
     FIG. 3 shows a close-up plan view of the turntable  140 , the collection bench rollers  160 , and the inspection bench rollers  190 . The turntable  140  is generally circular and supports a plurality of turntable rollers  150 , whose axes are generally parallel. Each of the turntable rollers  150  is driven by a turntable roller motor  300 , which is also supported by the turntable  140 . The turntable roller motor  300  drives a shaft  310 , and each turntable roller  150  is connected by an associated belt  320  to the shaft  310 . 
     The turntable  140  is mounted upon a spindle  330  which may be rotated by a turntable motor  340 . The angular position of the spindle  330 , and hence the turntable  140  to which it is attached, is measured by a pair of orthogonal turntable position sensors  350 ,  360 , as shown in FIGS. 4 and 5. The turntable sensors comprise a plurality of cam switches which start and stop the various motors as will be described in further detail below. It will be understood, however, that any suitable angular position transducer may be used. 
     A plurality of idler rollers  400 ,  400 ′,  400 ″ and  400 ′″ are also arranged around the circumference of the turntable  140 . 
     The turntable  140  is initially aligned such that the axes of the rollers  150  are each generally perpendicular to the direction of travel of the conveyor belt system  30 , i.e. as shown in FIG.  3 . When the person monitoring the screen  80  decides that no further manual investigation of an item of baggage is necessary, that item passes along the second conveyor belt  50  and onto the turntable  140  at the point marked A in FIG.  3 . The turntable rollers  150  are each rotated clockwise (see FIG. 5) to pull the item of baggage across the turntable  140  in the direction X (FIG.  3 ). As the item of baggage reaches the last of the turntable rollers  150 , it moves onto the collection bench rollers  160 . The collection bench rollers  160  are individually powered by 24 V motors mounted inside each of the rollers  160 . A low voltage supply is desirable to avoid the risk of injury if a person&#39;s hands gets caught in the collection bench rollers when attempting to remove an item of baggage from there. 
     As explained previously, the item of baggage moves across the collection bench rollers  160  and onto the series of lazy rollers mounted upon the collection bench  170  (FIG.  1 ). 
     On the other hand, when a person monitoring the screen  80  decides that an item of baggage must be investigated manually, an alarm (not shown) is triggered. The item of baggage moves off the end of the second conveyor belt  50  and onto the turntable rollers  150  on the turntable  140 . A detector (to be described below), detects when the item of baggage has moved onto the turntable rollers  150 , and the turntable roller motor  300  is switched off to prevent the item of baggage from moving further across the turntable rollers  150 . 
     Once the turntable roller motor  300  has been switched off, the turntable motor  340  is activated to rotate the turntable through 90°. Thus, the axes of the turntable rollers become parallel with the direction of movement of the conveyor belt system  30 , and perpendicular to the inspection bench  200 . The turntable position sensors  350 ,  360  sense when the turntable has rotated through 90°, the turntable motor  340  is switched off again, and the turntable roller motor is restarted, again driving each turntable roller  150  in a clockwise direction. Thus, the item of baggage is moved off the turntable and onto the inspection bench rollers  190 . As with the collection bench rollers  160 , each of the inspection bench rollers are individually driven by a low voltage motor. 
     The item of baggage moves off the driven inspection bench rollers  190  and onto the series of lazy rollers on the inspection bench  200 . 
     As soon as the item of baggage has moved off the turntable and onto the inspection bench rollers, the turntable roller motor  300  is switched off once more. Next, the turntable motor  340  is restarted, to rotate the turntable  140 , via the spindle  330 , back through 90°. It is preferable that the turntable motor  340  is bi-directional so that the turntable may be rotated either clockwise or counter-clockwise. 
     Once the turntable position sensors  350 ,  360  determine that the turntable has rotated back through 90°, the turntable motor  340  stops again. Thus, the axes of the turntable rollers  150  are re-aligned perpendicular to the direction of movement of the conveyor belt system  30 . 
     Provided that the next item to be loaded onto the turntable  140  from the second conveyor belt  150  does not require manual inspection, the turntable roller motor  300  is restarted, and items of baggage pass across the turntable to be collected by the collection bench rollers  160  once more. The turntable roller motor  300  continues to rotate until the next bag to be manually searched moves onto the turntable  140 . 
     In order to prevent items of baggage from being thrown off the turntable through centrifugal force as the turntable rotates, the speed of the turntable motor  340  is ramped up relatively slowly from zero to a constant operating speed. Similarly, the motor is ramped down slowly from the operating speed to zero once more, when the turntable has completed its 90° rotation. Ramping the motor up and down is accomplished by controlling the power to the motor, as will be described in connection with FIG. 6 below. Finally, the turntable motor is braked, for example by energising one of the phases only of the turntable motor, when the turntable motor is switched off. 
     Although the X-ray system described above can be controlled manually, it is preferable that the system be fully automated. To this end, the system is fitted with a plurality of pairs of photoelectric cells (PECs), which are arranged to detect the position of items of baggage throughout the system. The pairs of PECs are each linked to a central system controller such as a programmable logic controller, which operates the various motors driving the first and second conveyor belts  40 ,  50 , the turntable roller motor  300 , and the turntable motor  340 . 
     The location of the various PEC baggage position sensors is shown schematically in FIG.  1 . 
     A first pair of PECs  90  is located at the end of the first conveyor belt  40  distal from the input unit  20 . A second pair of PECs  100  is located and the second conveyor belt  50 , upstream of the X-ray unit  70 . A third pair of PECs  110  is located downstream of the X-ray unit  70 , again around the second conveyor belt  50  and adjacent to the turntable  140 . Finally, fourth and fifth pairs of PECs  120 ,  130  are located on opposite sides of the inspection bench rollers  190  and collection bench rollers  160  respectively. 
     Referring now to FIG. 6, a programmable logic controller  400  is shown. The programmable logic controller controls the automated operation of the X-ray system  10  based upon user inputs as well as signals from the pairs of PECs  90 ,  100 ,  110 ,  120 ,  130  which indicate the position of items of baggage within the system at any time. 
     A first item of baggage travels along the first conveyor belt  40  and on to the second conveyor  50 . As the first item of baggage passes the first pair of PECs  90 , a flag is raised in the programmable logic controller  400 . The motor driving the first conveyor belt  40  is then stopped when a second item of baggage reaches the first pair of PECs  90 . 
     When the first item of baggage passes between the second pair of PECs  100 , the flag in the programmable logic controller is reset, and the motor driving the first conveyor belt  40  is restarted. The procedure continues with third and subsequent items of baggage passing along the first conveyor belt  40 . Thus, no matter how closely the items of baggage are placed together in the input unit  20 , the items of baggage are suitable separated as they pass through the X-ray unit  70 . 
     The three pairs of PECs  110 ,  120  and  130  around the turntable  140  co-operate with one another to prevent baggage being forced onto the turntable whilst the turntable is in use. In the case where an item must be manually inspected, a signal is sent to the programmable logic controller  400  by the person monitoring the screen  80 . This signal is sent on a search line  410  in FIG.  6 . When the programmable logic controller  400  receives a signal on the search line  410 , it enters a “wait” state. As the item of baggage identified for search passes between the third pair of PECs  110 , the programmable logic controller exits the wait state and commences a “reject baggage” sequence. 
     In the reject baggage sequence, the controller  400  first sends signals to the first and second motor controllers  420 ,  430 . The first motor controller  420  in turn sends a signal on line  415  to the turntable roller motor  300  to ramp down the power to that motor until the rollers  150  stop rotating. Simultaneously, the programmable logic controller sends a signal on line  425  to the second motor controller  430  to ramp the power up on the turntable motor  340 . The programmable logic controller receives inputs along lines  440  and  450  from the two turntable position sensors  350 ,  360 , and sends second signals along the lines  415  and  425  to the first and second motor controllers  420 ,  430  respectively when the turntable  140  has rotated through the required 90°. The second signals along the lines  415 ,  425  start the turntable roller motor  300  and stop the turntable motor  340 . 
     As soon as the item of baggage moves off the turntable rollers  150  and onto the inspection bench rollers  190 , it passes between the fourth pair of PECs  120 . The programmable logic controller receives a signal from the fourth pair of PECs as the item of baggage passes between them. This signal indicates that the turntable is clear of baggage and may commence a “rotate back” sequence, where the turntable  140  is rotated back through 90°. Here, further signals are sent by the programmable logic controller to the first and second motor controllers  420 ,  430  respectively, to stop the turntable roller motor  300  and start the turntable motor  340  again. 
     The two turntable position sensors  350 ,  360  send a signal to the programmable logic controller  400  when the turntable  140  has rotated back to its original position, with the axes of the rollers  150  perpendicular to the direction of travel of the conveyor belt system  30 . This allows the turntable roller motor  300  to be started again in dependence upon a signal from the programmable logic controller  400  to the first motor controller  420  along the line  415 . 
     As well as triggering the above “reject baggage” and “rotate back” sequences, activation of the alarm to send a signal along search line  410  also causes the programmable logic controller to send a signal to the motor driving the second conveyor belt  50  (not shown in FIG.  6 ). As soon as the item of baggage to be inspected passes the third pair of PECs, the second conveyor belt  50  is then stopped to prevent further bags from being carried into the turntable  140  whilst the turntable is in use. 
     Once the turntable position sensors  350 ,  360  indicate that the turntable  140  is back in its initial position (with the turntable roller axes perpendicular to the line of travel of the conveyor belt system  30 ), the programmable logic controller sends a further signal to the motor driving the second conveyor belt  50  to restart it. 
     The purpose of the fifth pair of PECs  130  is similar to that of the fourth pair of PECs  120 . That is, the fifth pair of PECs detects when an item of baggage that does not need to be manually inspected has passed off the turntable and onto the collection bench rollers  170 . The programmable logic controller  400  will not send a signal to the turntable motor  340  to rotate it, until a preceding bag has moved fully off the turnable  140 , as indicated by the fourth and fifth pairs of PECs. 
     The third and fifth pairs of PECs also allow the system  10  automatically to handle oversized baggage. Any item of baggage which is longer than the diameter of the turntable  140  is considered oversized. If, having passed through the X-ray unit  70 , the person monitoring the screen  80  decides that no further manual investigation is necessary, then the oversized item of baggage simply passes across the turntable  140 , over the collection bench rollers  160  and on to the collection bench  170 , without difficulty. 
     However, if the oversized item of baggage requires further manual investigation, then the turntable  140  will need to rotate through 90° once the item has moved onto it. This is not possible with an oversized item of baggage. Therefore, to avoid this situation, which will cause a blockage to subsequent baggage passing along the conveyor belt system  30 , the third and fifth pairs of PECs are used. If an item of baggage moves on to the turntable  140 , and cuts the light beam of both the third and fifth pairs of PECs simultaneously, then rather than executing the “reject baggage” and “rotate back” sequences explained above, the programmable logic controller instead sends a signal to the motor driving the second conveyor belt  50  to cause it to stop. Simultaneously, the programmable logic controller  400  sends a signal to the screen  80 . This prompts the person monitoring the screen to advise the other person who is conducting manual investigation of baggage to remove the oversized item of baggage from the turntable manually. 
     The collection bench rollers  160  and inspection bench rollers may both rotate continuously. However, it is preferable that the collection bench rollers are stopped when the turntable rotates to move a bag onto the inspection bench, and similarly that the inspection bench rollers are stopped when the turntable is in its initial position to move baggage onto the collection bench. Again, this is carried out under the control of the programmable logic controller  400 , which is programmed to send a signal to a switch  470  when the turntable rotation sequence is initiated. In particular, as the programmable logic controller receives a signal on search line  410  to commence the reject baggage sequence, the switch  470  is simultaneously moved from contact with the collection bench rollers  160  to contact to the inspection bench rollers  190 . Thus, as the turntable  140  starts to rotate, the collection bench rollers stop rotating and the inspection bench rollers start rotating. Once the item of baggage has been deposited onto the inspection bench, the programmable logic controller  400  sends a second signal to the switch  470  to start the collection bench rollers  160  again whilst stopping the inspection bench rollers  190 . This is simultaneous with the commencement of the rotate-back sequence described above. 
     The whole system may be fitted with a manual override to allow emergency stops of all or part of the system  10 . For example, if an item of baggage has a handle or carrying strap which becomes caught in one of the turntable rollers  150 , this may be noticed by the person monitoring the screen  80 . To prevent damage to the motors and to the item of baggage, an emergency stop button may be depressed. This will send a signal to the programmable logic controller which in turn shuts down all of the system motors immediately. A further automatic shut-off signal is provided along “trip-tray” line  490  to the controller  400 . This operates to shut down the conveyor belt motors when a blockage occurs on the belts  40 ,  50 . 
     In addition to, or as an alternative to manual rejection of items of baggage by pressing an alarm, the programmable logic controller  400  may be programmed to reject every, say, tenth item of baggage automatically. This allows random double checks of baggage to be carried out. Any of the first, second or third pairs of PECs  90 ,  100 ,  110  can be used to send a signal to the controller  400  each time an item of baggage passes. The controller  400  counts ten items and then sends a signal on lines  415  and  425  to start the reject baggage sequence. 
     Whilst the example described above relates to an X-ray system for sorting hand luggage in particular, it will be appreciated that other applications are envisaged, for sorting a wide range of articles. For example, when carrying out X-ray investigation of hold baggage for airlines, the turntable may be fitted with a substantially more powerful motor as hold baggage is generally more rigid and is securely closed. Thus, the conveyor belt system  30  and the turntable  140  can each operate much more quickly. 
     Furthermore, it is possible to sort canned food by can size. In a system, for such a purpose rather than employing an X-ray unit  70 , a size detector would be used instead. The size detector would then send a signal to the turntable such that small cans, for example, are moved off the turntable in one direction, and larger cans in another. 
     Finally, it will be understood that, whilst only two directions (one parallel and one perpendicular to the direction of travel of the conveyor belt system  30 ) have been described, articles moving onto the turntable  140  can be moved off it in a large number of directions. For example, the turntable can be stepped in 30° angles from 90° to 270° simply by reprogramming the controller  400 . This would allow seven points of exit off the turntable. Thus, multiple selection of articles can be achieved. 
     ALTERNATIVE EMBODIMENTS 
     Although illustrative presently preferred embodiments and applications of this invention are shown and described herein, many variations and modifications are possible which remain within the concept, scope, and spirit of the invention, and these variations would become clear to those of ordinary skill in the art after perusal of this application. The invention, therefore, is not to be limited except in the spirit of the appended claims.