Abstract:
Fruit handling equipment comprising a conveyor having a plurality of linked carriages, each supporting at least one fruit carrying cup pivotally secured to the carriage, each cup having a latching mechanism operable to hold the cup in a fruit carrying mode and releasable to cause the cup to pivot to a delatched position to eject the fruit, and remotely controllable means in each carriage to release the latching mechanism.

Description:
This invention relates to fruit handling equipment and, in particular, relates to a conveyor system which carries fruit that is rotated past a photographic zone, weighed at a weighing zone and then ejected into appropriately positioned bins in dependence on the characteristics of the fruit as determined by the images taken at the photographic zone and the weight recorded at the weighing zone. 
     The term fruit as used herein embraces part spherical fruit and vegetables such as citrus fruits, apples, potatoes, tomatoes, and like shaped articles. 
     BACKGROUND OF THE INVENTION 
     Equipment of this kind usually utilises a series of carriages which are clipped onto a chain driven by sprockets. The carriages carry cups which support the fruit. A series of rotating rollers are arranged to rotate the fruit clear of the cups through a photographic zone. The fruit is then carried by the cups over a weighing zone in which the weight of each fruit is monitored. The cups are usually designed to pivot outwardly to cause the fruit to be ejected at appropriate positions along the conveyor determined by a computer that stores the data from the photographic and weighing zones. Equipment of this kind is very complex and thus expensive. The timing of the operation of components of the equipment is critical and thus setting up the equipment is a lengthy operation for a skilled individual. Furthermore, the power consumption of the motors which drive the sprockets is significant. 
     It is these issues that have brought about the present invention. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention there is provided a fruit handling equipment comprising a first conveyor adapted to transport a line of single pieces of fruit past a camera, over a load cell and through an ejection zone to eject the fruit at predetermined positions along the conveyor, and a second conveyor adapted to mesh with the first conveyor to lift the fruit off the first conveyor and rotate the fruit as it moves past the camera, characterised in that the first conveyor is a chain of fruit carrying carriages pivotally secured end-to-end to define a closed loop, and the second conveyor comprises a plurality of roller supports pivotally secured end-to-end to define a shorter closed loop, whereby each carriage pulls the adjacent meshing roller support. 
     Preferably, the fruit carrying carriages interlink with the roller carriages and the first conveyor drives the second conveyor. 
     Preferably, the respective carriages have interfitting formations which accurately line up the carriages and roller supports as the conveyor integrates. 
     In a preferred embodiment, the fruit carrying carriages and roller supports are manufactured in plastics. 
     According to another aspect of the invention there is provided a fruit handling equipment comprising a conveyor having a plurality of linked carriages, each supporting a fruit carrying cup supported in a cantilever fashion from each side of the carriage, each cup having a latching mechanism operable to hold the cup in a fruit carrying mode and releasable to cause the cup to pivot to a delatched position to eject the fruit, and remotely controllable means in each carriage to release the latching mechanism. 
     Preferably each carriage carries a radio controlled solenoid to trigger release of the latching mechanism. The solenoid may be powered by induction. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: 
         FIG. 1  is a side elevational view schematically showing a two lanes of fruit handling equipment; 
         FIG. 2  is a perspective view of the pair of lanes illustrating the inter-engagement of two conveyors forming part of the fruit handling equipment; 
         FIG. 3   a  is a perspective view of a roller assembly; 
         FIG. 3   b  is a side elevational view of the roller assembly; 
         FIG. 3   c  is a plan view of the roller assembly; 
         FIG. 3   d  is an end elevational view of the roller assembly; 
         FIG. 4   a  is a perspective view of a cup carriage assembly with the cups in a latched position; 
         FIG. 4   b  is a perspective view of the cup carriage assembly with one cup unlatched; 
         FIG. 4   c  is a sectioned perspective view of the cup carriage assembly with components removed to illustrate the latching assembly; 
         FIG. 5   a  is a plan view of one side of the cup carriage assembly; 
         FIG. 5   b  is a sectional view taken along the lines A-A of  FIG. 5   a;    
         FIG. 5   c  is the same section view but showing a cup in a delatched positioned; 
         FIG. 6  is a section view taken along the lines A-A of  FIG. 5   a  showing the cup in a weighing position; 
         FIG. 7   a  is a plan view of the cup carriage conveyor superimposed with the roller conveyor; 
         FIG. 7   b  is a cross sectional view taken through the lines A-A of  FIG. 7   a;    
         FIG. 7   c  is a side elevational view of the assembly shown in  FIG. 7   a;    
         FIG. 8  is a plan view showing part of a sprocket driving the cup carriage assemblies; 
         FIG. 9  is a cross sectional view taken along the lines A-A of  FIG. 8  and a partial section view taken along the lines BB of  FIG. 8 ; 
         FIG. 10  is a perspective view of a cup carriage running on a rail of the conveyor; 
         FIG. 11  is a sectional view of the carriage running on the rail; 
         FIG. 12  is a schematic circuit diagram illustrating the association of a radio transceiver and power supply with the fruit handling equipment; and 
         FIG. 13  illustrates the electrical circuitry carried by each carriage. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     General Layout 
     The fruit handling equipment of the preferred embodiment essentially comprises a series of parallel lanes each comprising a main conveyor  10  of interlinked fruit carrying carriage assemblies  20  that integrates with a second roller conveyor  11  at one end. A pair of lanes is illustrated in  FIGS. 1 and 2 . 
     The roller conveyor comprising a closed loop of pivotally interconnected roller assemblies  40 . The roller conveyor  11  is arranged to freely rotate around semi-circular guide drums  12 ,  13  positioned at each end of the conveyor  11  whereby as the main conveyor  10  returns, the carriage assemblies  20  mesh with the roller assemblies  40  to pass together through a photographic zone A near the end  15  of the main conveyor  10 . After the superimposed carriage and roller assemblies  20  and  40  pass the photographic zone A, the roller conveyor  11  descends a ramp  19  to disengage from the cup carriage assemblies  20  to return around the semi-circular guide drum  13 . The fruit carrying carriage assemblies  20  of the main conveyor  10  then continue to pass through a weighing zone B to an ejection zone C to return on the underside of the main conveyor  10  as shown in  FIG. 1 . The portion of the conveyor between the carriage and drum assembly separation and end  16  of the conveyor  10  is referred to as the active zone (AZ). 
     In this manner, a much shorter secondary conveyor  11  drives the roller assemblies  40  only at the photographic zone A. 
     The main conveyor  10  is driven at one end  16  by a metal sprocket  17  with plastic tipped teeth  18  and runs at the other end  15  integrated with the roller conveyor  11  on the drum  12 . The integration of the two conveyors  10  and  11  ensures that the main conveyor  10  drives the roller conveyor  11  around the drums  12 ,  13 . 
     Roller Assembly 
     As shown in  FIG. 3 , each roller assembly  40  of the roller conveyor  11  comprises a roller support  41  having two pairs of parallel flanges  42 ,  43  which extend in opposite directions parallel to the longitudinal axis of the conveyor  11 . The flanges  42 ,  43  support each end of a spindle  44  which supports a roller  45 . The roller  45  comprises two frusto-conical central members  46 ,  47  and two larger tapered outer members  48 ,  49  defining gaps therebetween. 
     The spacing of the roller flanges  42 ,  43  on one side is slightly less than the spacing of the roller flanges of the other side so that a series of roller carriage assemblies  40  can be joined together with the pins that support the rollers extending through the flanges  42 ,  43  of one roller assembly and the flanges of the adjacent roller assembly as shown in  FIG. 2 . In this way, the roller conveyor is made up of a series of interlinked roller assemblies  40  joined through the spindles  44  to provide a series of pivotal links forming the closed loop which constitutes the roller conveyor  11 . 
     The roller support has an upstanding tooth  98  designed to fit in the slot  62  created between 2 adjacent carriages  20  thereby locating each roller assembly with respect to the carriage conveyor  10  when the two conveyors merge as shown in  FIG. 7   b . In operation the leading vertical flange  96  of the carriage  20  acts against the upstanding tooth  98  of the roller support causing the roller conveyor  11  to be driven by the main conveyor  10 . 
     Carriage Assembly 
     In a similar manner, the main conveyor  10  is constituted by a series of links made up by interconnection of the fruit carrying carriage assemblies  20 . Each carriage assembly  20 , as shown in  FIGS. 4 to 6 , comprises a central carriage  21  which pivotally supports a pair of laterally extending radius arms  22  on each side, each radius arm  22  in turn supporting a fruit carrying cup  23 . The carriage  21  is of rectangular profile with a substantially planar underside  24  and an open recess  28  covered by a removable cover  29  with a pair of outwardly extending flanges  25  at one end supporting a pair of wheels  26  on an axle  27 . Two pairs of parallel outwardly extending flanges  25  coaxially fit onto the flanges carrying the wheels at the other end so that carriages can be interlinked through the axle  27  that extends through the flanges of one carriage and the flanges on the end of the adjacent carriage. In this manner, the carriages are pivotally interlinked to form a continuous loop to define the main conveyor  10  as shown in  FIGS. 1 and 2 . 
     The radius arm  22  comprises a curved beam with a T-shaped mounting flange  33  on one end which is pivotally secured across the side of the carriage  21 . The opposite end of the radius arm pivotally supports one end of the cup  23  through an elongate pivot  39 . The underside of the cup has two spaced legs  34 ,  35  that are arranged to extend freely through a pair of spaced apertures  36 ,  37  in the curved beam  22  of the radius arm. The pivotal connection of the radius arm  22  to the carriage  21  allows the cup to be supported in a fruit carrying position shown in FIG.  4   a  and an ejection position shown in  FIG. 4   b  in which the radius arm  22  pivots downwardly to eject fruit carried by the cup  23 . 
     As shown in  FIG. 4 , each cup  23  comprises a dished recess defined by five fingers  30  to define gaps  31  therebetween. The gaps  31  between the fingers  30  of the dish-shaped cup  23  are designed so that when the two conveyors are integrated and the roller assemblies  40  are superimposed on the carriage assemblies  20  the upper surfaces of each roller  45  can extend through the gaps  31  to engage the underside of the fruit to lift the fruit clear of the cup  23  for rotation through the photographic zone A as shown in  FIGS. 1 and 2 . Once the fruit has passed the photographic zone A, the conveyors  10  and  11  part, causing the rollers  45  to be lowered, as shown in  FIG. 8 , so that a single piece of fruit then rests on the dish-shaped cup  23 . 
     The radius arm  22  has a downwardly extending foot  38  that engages a latching mechanism  50  mounted in the recess  28  of the carriage  21  to control the position of the cup  23  relative to the carriage  21 . As shown in  FIGS. 5 and 6 , the latching mechanism  50  is a long piece of plastic moulding which includes an L-shaped latching arm  51  that is pivotally secured to the base of the carriage and a trailing detent  52  that is flexibly formed integrally with the rest of the moulding. The detent  52  has a trailing abutment  53  behind a shoulder  54  which is arranged to engage the base  55  of a well  70  formed in the centre of the cover  29  of the carriage. The L-shaped arm  51  accommodates the base of the foot  38  of the radius arm  22  and, as shown in  FIG. 5   b , there is a shoulder  56  on the interior of the L-shaped arm against which the foot  38  engages in the latched position. The weight of the radius arm  22  and cup  23  causes the assembly to pivot down about the pivot point P. This in turn causes the foot  38  to rest against the shoulder  56  in the L-shaped arm  51 , holding the assembly in the latched position, see  FIG. 5   b . When the detent  52  is pushed down by operation of the solenoid, it flexes relative to the arm  51  causing the shoulder  54  to ride clear of the base  55  of the well  70 . The arm  51  then pivots backwards causing the foot  38  to ride clear of the shoulder  56  allowing the radius arm  22  and cup  23  to pivot downwards into the unlatched position shown in  FIG. 5   c . The interior of the L-shaped arm  51  acts like a gear whereby the foot  38  meshes with its inner surface as it travels from the latched position shown in  FIG. 5   b  to the unlatched position shown in  FIG. 5   c.    
     The cups  23  remain in the unlatched configuration as they round the end  16  of the conveyor  10 . As they invert, gravity causes the cups  23  to return to the longitudinal position and an inclined plastic ramp  75  on the return consolidates the latching mechanism  50  of each cup  23 . 
     When the main conveyor  10  is assembled, the carriage assemblies  20  are pivotally interconnected through the shaft  27  on the wheels  26  so that there is wheeled support at each end of each carriage  21 . These wheels  26  are arranged to run on tracks  60 ,  61  that are formed by open rectangular aluminium beams  60 ,  61  which are located on the underside of the top of the main conveyor  10  and on the underside of the return, as shown in  FIGS. 1 and 2 . As shown in  FIGS. 10 and 11 , each beam  60 ,  61  has an open top with inturned flanges  68 ,  69  that support the wheels  26 . The position of the wheels  26  in the carriage is such that, as the carriage assemblies  20  invert on the return, the wheels  26  engage the lower track  61 . 
     The adjacent ends of the carriages  21  defines a rectangular slot  62  having a vertical flange  96  which, as shown in  FIG. 9 , engages the teeth  18  of the drive sprocket  17  rotating in a clockwise direction to impart drive to the main carriage conveyor  10 . 
     The vertical slot  62  also serves to engage with the upstanding tooth  98  on the roller supports to align and integrate the carriages  21  with the roller assembly so that the axes of the carriage wheels  26  coincide with the axes of the roller spindles  44 , thus aligning the axes of the pivot points of the links in both conveyors. In use the action of the leading vertical flange  96  of the slot  62  on the upstanding tooth  98  of the meshed roller support forces the roller conveyor  11  to move in unison with the main carriage conveyor. 
     Photographic Zone 
     As the two conveyors  10  and  11  merge on the return, the inverted carriage assemblies  20  support the roller assemblies  40  on the track  61 . As the integrated conveyors invert, the roller assemblies in turn support the carriage assemblies  20 . Between the drum  12  and ramp  19 , a pair of driven belts  9  are positioned on each side of the conveyors  10  and  11  to engage the underside of the rollers  45  to cause them to rotate about their axes to in turn rotate the fruit as it is lifted clear of the carrying cups  23  as the two inter-engaged conveyors move past the photographic zone A. The belts  9  provide the support for the assembly of the two conveyors  10  and  11 . At least one CCD camera is located in the photographic zone A to view the rotating fruit as it passes that zone and to forward a digital signal to a computer. 
     Weighing Zone 
     The spaced legs  34 ,  35  on the underside of each cup  23  are arranged to engage a load cell  67  arranged in the path of the underside of the conveyor  11  at the weighing zone B. As shown in  FIG. 6 , the load cell  67  lifts the cup  23  off the carriage  21  and ensures that there is no component of the horizontal movement distorting the actual weight measured by the load cell. The two-point weighing legs  34 ,  35  ensure that each piece of fruit is accurately weighed as it passes over the load cell  67 . The data is then fed to the computer. 
     Control of Ejection 
     The recess  28  which is formed in the carriage  21 , has a base that supports a first circuit board  71  and the well  70  that is positioned internally of the cover  29  houses a solenoid  72  with an upper circuit board  73  positioned on the top of the solenoid  72 . The solenoid has a plunger  74  that operates to push down against the abutment  53  of the detent  52  to release the latching mechanism as shown in  FIGS. 5   c  and  11 . The power to drive the solenoid  72 , the radio signal which activates the solenoid and the circuit associated with the release mechanism is illustrated in  FIGS. 12 and 13 . The well  70  is closed off by a lid  76  which sits flush with the cover  29  of the carriage  21 . The cover  29  and lid  76  and the associated well  70  ensure that the latching mechanism and solenoid release and associated circuit board  73  are housed in a clean discrete area where they will not be subjected to dust and debris which is often present in apparatus such as this. 
     The release of the cups  23  to the unlatched position is triggered by a remote activation system that operates on the use of a radio frequency signal to activate the solenoid. The section of the conveyor between the position where the rollers part from the carriages to the drive by the main sprocket is defined as the active zone (AZ) of the conveyor. It is in this zone that power is supplied to the carriages together with carefully controlled radio waves to trigger release of the latching mechanisms. The electrical circuitry is illustrated in  FIGS. 12 and 13 . 
     As shown in  FIG. 10 , each rail  60  in the active zone AZ of the conveyor has transversely positioned spaced brackets  80  which have upstanding lugs  81  that support a wire coil  82  in the form a rectangular frame closed at one end. This coil  82  is positioned adjacent the flanges  68 ,  69  which support the wheels  26  of the carriage  21 . The lugs  81  also supports a centrally positioned co-axial antenna cable  84  which is again positioned just under the carriage  21 . As shown in  FIG. 11 , the first lower circuit board  71  on the base of the carriage  21  is wired to the upper circuit board  73  positioned above the solenoid  72  in the well  70 . 
     The power is supplied to the solenoids by magnetic resonance inductive coupling between a long static power source coil, that is the wire coil  82 , and a small coil  85  mounted on the lower circuit board  71  in each carriage  21 . The magnetic inductive coupling is particularly desirable because there are no wearing parts. The static coil  82  is coupled to a tuning capacitor  87  as shown in  FIG. 12  to cause the coil to resonate at a frequency matched by a AC power source. The small coil carried in the base of the carriages  21  is tuned by capacitor  86  to resonate at the same frequency as the power supply so that, as the coil passes over the static coil, energy is transferred to the moving coil. Subsequently, the AC power from the small coil on the lower circuit board  71  is rectified and regulated to supply DC power to a super capacitor  88  on the upper circuit board  73 , see circuit diagram in  FIG. 13 . 
     Instead of supplying power by use of magnetic resonance, it is understood that each carriage could be powered by an electronic storage device such as capacitor or battery contained in each carriage. The preferred method of charging the storage device is an electromagnetic coil contained in the carriage passing over a magnetic field on the conveyor which causes and electrical current to be generated in the carriage coil. Other methods include microwaves, electromagnetic induction, or direct driven using the motion of the conveyor carriage. Alternatively the power may be supplied via a direct electrical contact with a supply source i.e. using brushes, pins or through the wheels. The power may also be supplied via a replaceable battery or other storage device. 
     The radio frequency (RF) system comprises a base RF transceiver per row of carriages. Each transmitter serves two lanes and is controlled by the computer. Each carriage carries a transceiver. To minimise transmission distance from the base to the receivers, the co-axial antenna  84  runs parallel to and immediately below the carriage bases. This configuration minimises RF power and reduces the likelihood of interference between adjacent pairs of lanes. It is also understood that the use of slightly different carrier frequencies on adjacent lanes further reduces interference issues. 
     Since power consumption of the remote circuit board in the RF active mode is relatively high, the RF activity is restricted to the active section of the conveyor. On each remote circuit board, at the point where the capacitor charging ceases, just prior to the main drive sprocket, the RF system is switched off and the processor enters a low power consumption sleep mode. At the recommencement of charging, the processor is woken and the RF system reactivated at the start of the active zone (where the rollers separate from the carriages). As the length of the conveyor where the RF system is active corresponds with the charging zone, the super capacitor  88  remains fully charged. This capacitor is required as a buffer for the electronics when in sleep mode and for a short, high powered burst to operate solenoids S 1  and S 2 . The capacitor also maintains power to the circuit boards during short breaks in conveyor operation. 
     In this ejection system, the link (carriage assembly  20 ) houses an electronic circuit that can receive and process radio signals (or other type of electromagnetic signal) from the main conveyor controller which would be coupled to the computer. This signal tells the link when or where to delatch the cups. The conveyor controller tells the link when to drop by calculating or identifying its location and then sending the signal to delatch the cups when the link is in position at the drop point. Alternatively the conveyor controller may send the signal to the link to delatch at a predetermined location. The link then senses (by barcode and optical sensor, RFID tag, counting pulses to measure distance or time or other suitable means) when it has reached the correct location and delatches. 
     An advantage of this ejection system is that the delatching is triggered remotely from the conveyor controller. So long as the cup is in approximately the correct location with respect to the drop point (say 50 mm) it can be triggered by the controller. This also means that the cup triggering position may be varied automatically by the controller depending upon the conveyor speed thereby allowing for the trajectory of the fruit and giving control over the where the fruit lands. 
     Jitter 
     As shown in  FIG. 9 , the drive system has been specifically designed to eliminate chordal action which usually results in significant oscillation in conveyor velocity due to the large pitch conveyor chain being positioned around a relatively small drive sprocket. The drive sprocket  17  which directly drives the carriages  21  has sixteen teeth, each of which is covered with a plastics tip  18  to reduce noise and wear. However, as the carriages  21  move over the plastics coated tips  18 , a pulsing action is generated which can cause between 1% and 1.5% speed change. This is usually referred to as jitter. Instead of directly driving the shaft of the main sprocket  17  through an electric motor, a separate smaller chain drive  92  is provided in which the output sprocket  93  on an electric motor (not shown) is coupled to a smaller drive sprocket  94  mounted on a shaft  95  which is common to the main driving sprocket  17 . A conventional chain  92  effects this drive. The smaller drive sprocket  94  is also designed to have sixteen teeth but operates at a different pitch. The drive to the smaller drive sprocket  94  introduces jitter in the same way that the main drive introduces jitter. In this system, the jitter of the smaller drive sprocket  94  is arranged to be timed to be inverse to the jitter caused by the main sprocket  17  so that the two jitters balance to provide a smooth drive. 
     Features 
     The majority of the components of this conveyor are manufactured from plastics. The plastics components are designed to be produced through a simple moulding process and the use of plastic componentry to make up the links of the two conveyors substantially reduces the overall weight of the assembly by doing away with a conventional chain to, in turn, substantially reduce the power required to drive the assembly. The assembly is also designed to reduce drag. The carriages run on wheels that engage a track even in the return configuration, see  FIG. 2 . It is estimated that the assembly will operate on 25% of the power used to drive similar such assemblies. The use of plastics for the componentry of the assembly also substantially reduces the noise of the equipment in operation. The noise can be further reduced by coating the portion of the track which engages the wheels of the carriages and, as described earlier, coating the tips of the drive sprockets. 
     Conveyors of this kind are usually 50-60 m in length and thus providing a much smaller roller conveyor of about 8 m in length substantially reduces the number of components and complexity of the arrangement. The inter-engagement of the two conveyors is shown with reference to  FIG. 7 . The axes of the wheels  26  on the cup carriage assemblies  40  are arranged to align with the axes of the rollers  45  on the roller assemblies  40 . The underside of each roller support  41  has a central portion which defines a centrally positioned, upstanding trapezoid tooth  98  that is arranged to be a sliding fit against a vertical flange  96  at either end of the carriage  21 . The vertical flanges  96  of adjacent carriages  21  define leading and trailing walls of the slot  62  which accommodates the trapezoidal teeth  98  of the roller support  41  as shown in  FIG. 7   b . In this way, as the two conveyors come together, the upturned roller conveyor  11  engages and supports the carriage  21  of the main conveyor  10 , causing the axles  27 ,  44  of the wheels  26  and rollers  45  to align and bringing the two conveyors into a meshed configuration. Alignment of the axes of the pivot points of the roller carriages with axes of the roller assemblies when the two conveyors are meshed allows the meshed section of conveyors to flex and travel around the semicircular drive drums without any longitudinal movement between the two conveyors. The location of the tooth  98  against the flange  96  takes up any slack in the pivots between carriages  21  and roller supports  41  and ensures that the two conveyors  10 ,  11  are accurately aligned when they come together. The action of the leading vertical flange  96  of the slot  62  against the tooth  98  of the roller support  41  allows the main carriage conveyor  10  to impart the driving force to the roller conveyor  11  thereby allowing the single drive sprocket  17  to power both conveyors 
     As the two conveyors  10  and  11  part after the photographic zone A, the roller conveyor  11  simply drops away from the underside of the cup conveyor  10 , see  FIGS. 7   b  and  7   c . The all plastics componentry reduces the running resistance and the reduction in the number of rollers reduces the load on the main conveyor thus substantially reducing the power needed to drive the assembly. It is envisaged that the equipment described above is cheaper to build, simpler to assemble and maintain and uses substantially less energy. The assembly is quieter, more efficient and more reliable and, in consequence, easier to service. It is thought that the accuracy of the equipment will be also enhanced. 
     In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.