FRUIT SORTING EQUIPMENT

Fruit sorting equipment comprising interlinked carriages forming a conveyor driven in a conveying loop, each carriage having a fruit carrier attached to the carriage to pivot about a pivot axis, each carrier supporting two longitudinally spaced pairs of axially rotatable rollers that support the fruit above the carrier, and driving means to cause the rollers to axially rotate.

INTRODUCTION

This invention relates to fruit sorting equipment and, in particular, relates to a conveyor system which carries fruit for sorting.

BACKGROUND OF THE INVENTION

Fruit sorting equipment carries fruit on a conveyor system whereby the fruit 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.

Fruit sorting equipment is also used in automated packing stations where the fruit are orientated in a particular manner to ensure desirable characteristics like blush are visible to the potential customer. There is also a trend to ensure stalks of the fruit are aligned for better presentation.

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 equipment is critical and thus setting up the equipment is a lengthy operation for a skilled individual.

Some fruit, especially pears, are difficult to align in the cups in a manner that they can be axially rotated past the camera. Pears also have relatively tough stalks that can catch in the conveyor causing catastrophic jambs.

In automatic packing stations there is often a requirement for the fruit to be aligned uniformly both with respect to the direction of the stalks and presentation of the fruit.

It is these issues that have brought about the present invention.

SUMMARY OF THE INVENTION

According to one aspect of the present invention fruit sorting equipment comprises interlinked carriages forming a conveyor driven in a conveying loop, each carriage having a fruit carrier attached to the carriage to pivot about a pivot axis, each carrier supporting two longitudinally spaced pairs of axially rotatable rollers that support the fruit above the carrier, and driving means to cause the rollers to axially rotate.

In another aspect the present invention also provides fruit sorting equipment comprising interlinked carriages forming a conveyor driven in a conveying loop, each carriage having a fruit carrier attached to the carriage to pivot about a pivot axis that is longitudinal to the conveyor, each carrier supporting a roller assembly comprising axially rotatable rollers that support the fruit above the carrier, and driving means to cause the rollers to axially rotate at different speeds and/or different rotational directions allowing for re-orientation of fruit.

The term fruit as used herein embraces, part spherical fruit and vegetables such as citrus fruits, apples, potatoes, tomatoes, and like shaped articles. The term fruit also embraces less spherical objects such as pears, capsicums and similar shaped fruit or vegetables.

The driving means may be a drive member having a friction surface that engages the underside of the roller to impart rotation to the roller as the conveyor moves across the surface. The friction surface may be stationary or a driven surface such as a belt or chain. In a preferred embodiment each carrier has two longitudinally spaced pairs of rollers, each roller being free to axially rotate relative to the carrier.

Preferably the driving means comprises two longitudinally spaced pairs of belts. The first pair of belts engaging the underside of the rollers at the start of the conveyor to cause rotation of the rollers on each side of the carrier and a second pair of belts positioned downstream of the first pair to engage rollers on each carrier to cause rotation of the rollers under an overhead camera.

Preferably each carriage comprises a central link with a laterally extending arm pivotally secured to each side of the link, each arm pivotally supporting a carrier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fruit sorting equipment illustrated in the accompanying drawings comprises a conveyor10shown inFIGS.1to4, formed by a series of interlinked carriages50that form a closed loop supported by beams11and12. The closed loop is oriented vertically so that a fruit supporting part of the carriage is positioned above a return part of the conveyor. The carriages are plastic mouldings pivotally interlinked and are driven by a drive sprocket13at a far end with an idler sprocket14at the infeed end to form moving conveyor10. The carriages50define two parallel lines of fruit. While the described embodiment describes two parallel lines of fruit the carriages could simply be configured to define one line of fruit to be moved along the conveyor, whether that line of carriages is positioned to one side or centrally of the conveyor. Fruit F are fed down chutes15at the infeed end to a loading zone16, to then pass to a photographic zone17and a weighing zone18to finally an ejection zone19in which the fruit are ejected into collection chutes20.

As shown inFIG.5each carriage50comprises a central link51which pivotally supports an arm52on each lateral side of the central link51with respect to the conveying direction (longitudinal) of the conveyor10. Each arm52has a base frame69which supports a carrier and roller assembly70. The link51has a curved roof63supported by a web53extending from a base frame54that is supported by the beam11of the conveyor10. Each side of the frame54has outwardly projecting flanges55,56with axially aligned apertures57that locate pivot pins62on the base frame69of the arm52. A curved skirt58extends across the inner side of the arm52. The pivot pins62allow the arm to pivot through approximately 90 degrees relative to the link51, or as far as required to tip fruit off the carriage at the ejection zone.

The carrier is attached to the carriage at a pivot axis that is longitudinally aligned to the conveyer direction. Foreseeably, there may be designs of carrier and carriage attachments where the pivot axis is not longitudinal to the conveyor, but may be perpendicular, or even angled to the conveyer. Such designs would still achieve the same outcome of the carrier pivoting relative to the carriage in order to tip fruit from the conveyor. For example, the carrier could be attached to pivot on a support rod that protrudes outwardly of the central link in a direction perpendicular to the direction of travel of the conveyer. By this design, the carrier would pivot perpendicularly to the conveyer in order to tip fruit from the conveyor.

The planar base69of the arm has laterally projecting feet60,61. The base69supports the carrier and roller assembly70with one edge59pivotally secured to the feet60,61. This allows the carrier and roller assembly70to lift a short distance off the arm52.

The carrier and roller assembly70comprises a frame71that supports four longitudinally and transversely spaced frustoconical rollers72to75. The rollers72to75are free to axially rotate and are frustoconical with their peripheries79tapering towards the centre of the frame71. The rollers protrude through the bottom surface of the carrier. The frame71has a curved upper surface76slightly below the height of the rollers72to75. The curved surface76defines a depression85into which a single piece of fruit can descend. The movement of the rollers72to75is used to rotate and re-orientate the fruit.

As shown inFIGS.7and8the curved roof63of the link51is above the curved surface76of the frame71of the carrier70so that fruit descends under gravity into the depression85defined by the carrier frame71. Furthermore the depression85holds a single piece of fruit and the curved surface76ensures fruit cannot locate between adjacent carriers.

An outer flange77of the base frame71is pivotally secured via edge59to the feet60,61of the arm52. The carrier and roller assembly70rests on the arm52which is supported by the link51in a cantilever fashion. A spring-loaded catch80is used to hold the carrier70in the horizontal position shown inFIGS.6to9. When the catch80is released the weight of the carrier70causes the carrier70and arm52to pivot down through approximately 90 degrees as shown inFIGS.17and18.

As shown inFIG.17the catch80is fitted to the link51via pivot pins81and engages with an extension82of the arm to hold the arm and carrier and roller assembly in a horizontal position during loading, inspection, weighing and then release the arm when required at ejection. Actuation of the catch80is via a solenoid arm86mounted on the beam11. The catch80is restrained in the latched position via a small spring84.

As shown inFIG.10the carriages50are pivotally interlinked via pins64through aligned holes65at each end of link51to form a continuous conveyor10. The curved upper surface76of each carrier frame71and roof63of the link51are shaped to define smooth virtually unbroken surfaces merging into the depression85into which the fruit F locate resting on the roller peripheries79. The virtually unbroken surfaces ensure that there is little opportunity for stalks to catch in the componentry. When the carriers70are tipped as shown inFIG.17the trailing curved skirt58of the arm52is shaped to define a curved surface against the roof63of the link51again reducing the likelihood of stalks catching in the componentry.

Operation of the Conveyor

As shown inFIG.1the conveyor10starts with a loading zone16that merges with a photographic zone17to a weighing zone18and finally to an ejection zone19where the fruit are discharged for collection in appropriate bins.

Loading Zone

Details of the loading zone16are shown inFIGS.10to12. Continuous friction belts90,91span a section of carriages and are positioned under the outer edge of the carriage rollers72,73and74,75in the carrier and roller assembly70on each side of the central link51. Electrically driven sprockets98,99drive the belts90,91and the belt speeds are controlled to vary the speed and if necessary the direction of rotation of the belts thus varying the speed and direction of rotation of the opposed rollers72,73and74,75. The speed and direction variability is selected to cause the fruit to singulate and rotate to the desired orientation, which in the case of pears, is with their longitudinal axis transverse to the conveying direction. Accordingly, the pairs of rollers72,73and74,75can be independently driven by the driving means of belts90,91to rotate at different speeds and/or in opposite rotational directions in order to rotate the fruit about a vertical axis on the carrier and roller assembly70into the desired position ready for photographing and/or packing.

A particular feature of the conveyor10is the rollers72-75being separate on the left hand and right hand sides of the carrier frame71(when viewed from the direction shown in, for example,FIG.6). This allows the use of two roller rotation belts90,91below the carrier and roller assembly70which gives the additional ability to rotate the fruit around a vertical axis by varying the speed differential between the two belts.

Photographic Zone

Once the fruit are singulated and orientated by the first set of belts90,91the second set of driven belts94,95rotate the fruit under a camera96in the photographic zone17. The second set of belts94,95are positioned under the rollers72,73and74,75to cause rotation of the rollers due to the speed differential between the belts94,95and the conveyor10. This differential is adjustable to ensure comprehensive photography of the fruit. Each roller72to75is over-moulded in soft rubber to increase the friction between the belts and the rollers and to protect the fruit from bruising. Weighing Zone

Once the fruit are past the photographic zone17the rollers72to75are conveyed off the belts94,95to become stationary. The fruit then moves to the weighing zone18shown in detail inFIGS.13to16. As described earlier, each carrier and roller assembly70is pivotally secured to the outer edge of the arm52and the inner edge of the arm52is pivotally secured to the link51to allow the arm52and the carrier and roller assembly70to lift slightly relative to the link51as the conveyor moves over a small ramp104shown inFIG.13. The carrier frame71has two downwardly extending lateral spaced feet100,101that ride up onto a load cell102under the conveyor10. The two feet100,101keep the assembly horizontal in one axis as it travels up the ramp104, over a weighing plate105which is attached to the load cell102. The assembly then descends down a trailing ramp106. The parallel pivots between the link51and the arm52, and the arm52and the carrier70restrain the carrier and roller assembly70horizontally in the opposite axis thereby allowing free vertical travel for weighing. The pivots are specifically designed to minimise vertical travel friction. The vertical travel creates a gap between the extension82on the arm52and the release catch80and also the inner edge of the carrier where it rests on the arm (seeFIG.16). This provides an accurate weighing result.

Ejection Zone

Once the fruit F has gone past the weighing zone18, they reach an ejection zone19for ejection in dependence on size, weight and other characteristics such as colour, shape and blemishes. A computer (not shown) monitors these variables and sends a signal to solenoids87positioned under the conveyor10on each side as shown inFIGS.17and18. The solenoids have arms86that engage and release the catch80to cause the carrier and roll assembly70and arm52to fall down by gravity through approximately 90 degrees to the tipped position shown inFIGS.17and18, thus causing ejection of the fruit into the chute20to be transferred to appropriate storage bins (not shown).

In the embodiment shown inFIGS.19to21a soft cylindrical brush130is positioned over the carriages50in the loading zone16. The brush130has its longitudinal axis parallel to the direction of travel of the conveyor10. As shown inFIG.20which illustrates pears as the fruit F, the brush130is driven to rotate quickly about its axis so that the soft bristles131move perpendicular to the direction of the conveyor. If the two roller belts90,91below the carriers70are travelling at the same speed and slightly faster than the conveyor10then this will rotate the rollers72-75in the carrier70causing the fruit (pears) in the position shown as F1(from left) namely lying down parallel with the conveyor with a trailing stalk, to an upright position shown as F2. As the fruit stands up the upper half of the fruit and stalk comes into contact with the soft bristles131of the rotating brush130. The force of the brush pushes the top of the fruit sideways causing the fruit to assume the desired position of F3namely, lying down with the fruit's longitudinal axis approximately horizontal and perpendicular to the conveyor direction of travel. This is the ideal position for rotation of the fruit past the camera in the photographic zone.

In another embodiment shown inFIGS.22to24a solenoid chain140is added to the conveyor10at the loading zone16. The solenoid chain140is used to lift the carrier70and rollers72-75off the drive belts90,91when the fruit are in the desired position to stop rotation of the rollers72-75and ensure against further movement of the fruit F. Each link141of the chain contains a solenoid powered remotely, the solenoid having a plunger143that is vertically displaceable to engage the feet100,101on the carrier70to lift it slightly so the rollers move clear of the belts90,91and stop rotating.

The solenoid chain140is driven by a sprocket (not shown) to run on a guide (also not show) at the same speed as the main conveyor10so that the solenoids are aligned directly below the two feet100,101on the underside of each carrier70. A camera145views the fruit and sends a signal to a computer that determines when the fruit are in the preferred optimal position. The computer then activates the solenoid to push the carrier70off the belts90,91thereby stopping the rotation of the rollers72-75and the fruit. This stopped configuration is shown on the right hand side ofFIGS.22and23. As the carriers move off the belts90,91all of the rollers stop rotating.

The rollers are permanently fitted to the carrier70and actually become the contact for the fruit for all operations. This contrasts with existing designs where there is a constant meshing and moving apart of carriers and rollers. This carrier and roller design greatly simplifies the design of the conveyor parts and also the complexity of the rest of the equipment.

Once the fruit is settled on the four rollers, the rollers effectively combine both functions of the separate rollers and carriers. In other words, the carrier and roller assembly functions firstly as a roller for the purposes of rotation of the fruit for singulation and for vision inspection and secondly as a carrier for the purposes of weighing, transfer to outlets and ejection of fruit.

Fruit density, in terms of number of fruit items per metre length of conveyor, is not compromised with the described fruit sorting equipment. It is, in fact, comparable to fruit density of known fruit conveyors.

The carrier, in addition to supporting the four rollers, by design of its shape serves to direct the fruit under gravity into the space above the four rollers rather than between this set of four rollers and the next four rollers in the adjacent carriers and helps prevent the fruit collecting in doubles.

The rollers protrude sufficiently above the carrier surface such that they suspend the fruit above the carrier surface. This assists in ease of rotation of the fruit about both horizontal and vertical axes.

The rollers are permanently fitted to the carrier rather than other existing designs where rollers are constantly meshing with the carriers and then and moving apart again. This means that clearances between the roller and the carrier surfaces can be made very small which prevents gaps where stalks and foreign objects can be caught. This should result in less damage and crashes of the machinery.

Two spaced apart pairs of rollers, namely four rollers, have been described in relation to the embodiments presented herein. However, more than two pairs of rollers could foreseeably be incorporated into the fruit sorting equipment for the purpose of supporting larger fruit, such as melons. An additional one, two or more rollers, or pairs of rollers may foreseeably serve to provide for alternative alignment options for fruit rotation around differently aligned axis, or to accommodate differently shaped or sized fruit, such as elongated fruit and vegetables.

Combined with a very curved and organic shape, the carrier and roller assembly provides no surfaces or edges where fruit stalks can catch. This is particularly advantageous when sorting fruit with stiff stalks like pears and capsicums.

Incorporating the rollers into the carrier means that the carrier has become a large squarish shape in plan view, which means that it has been possible to place the pivots for both the arm to link and arm to carrier at close to the four corners, maximising the length between pivots and pins. This helps minimise the effect of friction in the pivots and optimises weighing accuracy.

It is to be understood that the afore going description refers merely to preferred embodiments of invention, and that variations and modifications will be possible thereto without departing from the spirit and scope of the invention, the ambit of which is to be determined from the following claims.