Systems and methods of continuous conveyor feeding

An automated system and method for continuously feeding articles onto a moving conveyor belt are described. The automated system includes a plurality of partitions forming the conveyor belt; a controllable drive configured to continuously advance the conveyor belt; at least one gripping element configured to controllably grip and lift the articles, and at least one divider bridge configured to sustain a linear movement of the gripping element along the divider bridge, at a predetermined angle relatively to the conveyor belt.

TECHNICAL FIELD

This present invention relates to a system and method of continuously feeding a conveyor while in motion.

BACKGROUND OF THE INVENTION

As far as herbage crops in general are concerned, the market for all kinds of spices has developed and grown to such extend that the supply is unable to meet the demand in reasonable price, due to the high cost of manual labor needed in sorting harvested crops of various types like chives, green onion etc.

For many years many attempts have been made to minimize the need for manual labor in sorting of various types of vegetables and fruits. To date, there are some mechanized sorters which are practical, effective and efficient pertaining to grain crops, fruits or vegetables, but sorting of herbage crops is still performed by manual labor.

Lately a growing difficulty to market herbage crops has developed due to unavailability of manual labor. For example, the method of sorting chives to date is as follows: Chives arrive from the greenhouse to the packing-house in crates as bundled bunches placed one next to the other. Each bunch contains stalks in different lengths and conditions. Some are too short, curved and yellowish, others are infected, splintered, striped or having burned edges. In order to receive competitive good quality bunches having the required weight, the workers have to perform the following tasks: to cut manually the edges, to shake the bunch in order to get rid of the flawed ones, to sort manually the stalks and remove the damaged ones. (e.g. 100 gr. chives contain about 300 stalks). To weigh manually each bunch, add or lessen stalks in each bunch in order to receive the desired weight, to manually bundle each bunch and pack for delivery.

A highly trained worker is able to provide 15 kg finished and packed stalks bunches daily. The sorted crop weighs 30% of the raw stalks. 70% wastage results from the above described process and the over-weight deriving from manual weighing.

Until recently there were only two ways to feed stalks into compartments vertically to a moving conveyor belt: (1) Starting a work cycle by stopping the moving conveyor belt, hand feeding the products while the moving conveyor belt stands still, and once the compartments on the conveyor belt are loaded, restarting movement. (2) Starting a work cycle while synchronizing the feeding system to speed of the conveyor belt. Once the feeding system is disposed above the compartments on the moving conveyor belt, the products are disconnected from the feeding system into the compartments and the feeding system returns to point 0.

U.S. Pat. No. 4,018,674 to Morris disclosed a system for sorting tobacco leaf. In the system the leaves are carried on a horizontal endless belt conveyor past a sensing station, the method of delivering the leaves from a source to the conveyor comprising the steps of feeding within an enclosed housing vertically disposed above the conveyor a random stream of the leaves so as to fall perpendicularly to the conveyor deflecting the leaves in a plurality of selected paths, each intersecting a major portion of the perpendicularly falling stream within the housing transversely to the direction of movement of the conveyor before reaching the conveyor, each of the selected paths being inclined in a direction obliquely angular to the perpendicular direction of the falling stream, the direction of movement of the conveyor and the plane of the conveyor to cause the leaves within the falling stream to be deflected at different times and move relative to each other sequentially downwardly at angles to the direction of the vertical stream, the conveyor and the direction of movement of the conveyor and depositing the leaves on the conveyor in spaced orientation.

In high throughput, when products are tightly wrapped and in motion, performing cuts is not simple and is quite a technological challenge. The problem is increased, for example, when the stalk to be cut is one out of a tightly wrapped package in high motion, and it is necessary to avoid touching the nearby stalks. The technology exists but it is very expensive, complicated and not practical, when it comes to relatively cheap products, like herbage crops.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a system and method of feeding a conveyor while in motion and preferably sorting long and thin products including herbage crops, such as harvested crops of various types, like chives, green onion, etc., as well as plastic or light metal sticks, hereinafter collectively referred to as articles.

It is a further object of the present invention to provide a system and method for automated feeding a conveyor while in motion and of sorting of articles and stalks, including inspection for flaws, adjustment of length and weight, bundling and packaging.

Until recently the common way in industry for cutting products is by moving knives toward the object to be cut or moving a plated product toward the knives. The present invention introduces a cheap and practical system and method for shake and cut articles, including stalks to replace the manual shake and cut process. When used for stalks, the system of the invention may load between 50-70 stalks every few seconds from a feeding tray into a conveyor belt partitions.

The system includes a conveyor belt drive and inspection systems, which enables high throughput performance. The feeding system comprises a controllable drive, electronically synchronized with the conveyor belt drive, so that each stalk loaded in each partition may be individually handled.

The stalks in the partitions are preferably further photographed and programmatically analyzed. The analyzed results determine which stalk is emitted, cut or sorted to be automatically bundled and packaged.

According to the present invention an improved system and method of feeding a conveyor while in motion is obtained by synchronized movement of a gripping element relatively to the conveyor belt. The articles are collected from the feeding tray, which is placed next to the conveyor belt, by the gripping element and conveyed in controlled speed and at a predefined angle relatively to the direction of movement of the conveyor belt and then synchronically fed into the proper compartments.

According to the present invention the feeding system moves in predefined angle relatively to the direction of movement of the conveyor belt, whereas the speed vector of the feeding system is synchronized according to the predefined angle to the speed of movement of the conveyor belt. The synchronization of the feeding system ensures the relative linear speed between the articles and conveyor belt substantially equals to zero.

At the end of the feeding cycle the feeding system loses grip of the articles. Once the articles are placed into partitions of the conveyor belt, the feeding system returns to a starting point. Meanwhile, the conveyor belt keeps moving uninterruptedly. The feeding system loads again another bunch of unsorted articles and awaits the synchronism to the next loading cycle.

The synchronization of the feeding system is obtained by controlling the movement of the servomechanism drive of the feeding system and the drive system of the conveyor belt. The software parameters may be determined electronically by an industrial PLC controller or PC computer. In another embodiment of this invention, the feeding system is timed mechanically.

A combined system includes the feeding system and a system of cutting long flexible articles (e.g. herbage crops) is further disclosed. The stalks or any other long and thin product arrive to the packing-house in crates as bunches placed one next to the other on designated feeding try. Each bunch contains stalks in different lengths and conditions which are placed on the feeding trays.

The feeding system loads stalks from a feeding tray and places them into conveyor belt partitions. The collecting of the stalks may be performed by vacuum, magnetic field, physical gripping or any other known means. The feeding system preferably comprises a servomechanism drive electronically synchronized with the drive system of the conveyor belt, so that every 1-3 stalks are placed in each partition the conveyor belt to be potentially individually handled, while the conveyor belt advances continuously.

The conveyor comprises a motorized drive which carries the pulling wheels, e.g. chain or timing wheels. Each cycle the drive causes the advancement of the conveyor, according to the respective gearing ratio with the drive. On the motorized drive which pulls the conveyor an encoder is preferably attached, providing data about the angular position of the wheel.

According to encoder data the speed and location of the conveyor in any given moment is calculable. A controlled servo engine including an encoder preferably drives the feeding system, at a predetermined angle towards conveyor belt, controlling the and speed and timing of movement. The control driver of servo engine receives data constantly from the encoder associated with the conveyor belt. Once the synchronization order is received the engine moves the articles to conveyor belt according to the required gearing factor which equals to 1/COS α of conveyors' speed, where “α” is the angle between the conveyor to the feeding system's direction.

When reaching the feeding finish line, the feeding system drops the products and returns to the initial position, ready for the next cycle.

While the articles are in partitions being transferred they are photographed and programmatically analyzed. The analyzed results determine which stalk is to be emitted, cut or sorted as well as automatically bundled and packaged.

According to above results, the stalks are then channeled to different compartments. Those who are to be cut are conveyed to the cutting apparatus. All above tasks are performed without stopping the movement of the conveyor.

When the loaded compartments reach the cutting apparatus, the stalks are forced towards sharp knives by an air pressure system. The flexible stalk bends towards the knives due to the synchronized air pulses on it. The quick encounter with the sharp knives makes the cut at the meeting point and the remained flexible product straightens in its compartment as shown and advances to the bundling and packaging area.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown merely by way of example in the drawings. The drawings are not necessarily complete and components are not essentially to scale; emphasis instead being placed upon clearly illustrating the principles underlying the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made toFIG. 1A to 1E, showing a combined system comprising automated feeding system106and a cutting system109for long flexible articles102(e.g. stalks). Articles102arrive as bunches and are placed on designated feeding try100. Each bunch contains articles102in different lengths and conditions. Once the articles102are placed on the feeding tray100, automated feeding system106is configured to feed articles102into conveyor belt partitions101.

The feeding system106comprises feeding tray100, conveyor belt partitions101into which the articles102are fed, divider bridges104which define the direction of the movement of articles102towards the conveyor belt. Gripping element103, shown inFIG. 2A-C, is configured to grip the articles102, for instance by vacuum, magnetic field, physical gripping or any other suitable means, so as to feed them into conveyor belt partitions101. Mounting elements105define the direction towards and/of angle between divider bridges104conveyor.

The conveyor belt comprises a plurality of belt partitions101, a motorized drive (not shown). Each cycle the drive causes sledding predetermined advancement of the conveyor belt, according to the respective gearing ratio.

An encoder is preferably attached to the drive which pulls the conveyor, providing data about the angular position of the drive. According to encoders' resolution, it is possible to calculate the exact speed and location of the conveyor in any given moment.

A controlled motor (typically servo including an encoder) operates the feeding system106, moving gripping element103forward and backward at a predetermined angle, controlling the speed and location of the movement. The controlled receives data constantly from the encoder of the conveyors belt drive. The driver of synchronizes the movement of gripping element103with the movement of the conveyors belt. Once the synchronization order is achieved gripping element103moves respectively to conveyors' encoder, according to a preset gearing factor, wherein the speed of gripping element103along the conveyor belt equals to the speed of gripping element103along divider bridges104multiplied by COS α, where “α” is the angle between the conveyor belt and of feeding system106and COS represents Cosine function.

Reference is now made toFIG. 3A to 3D, showing a consequence of steps in the process of feeding articles102into conveyor belt partitions101by feeding system106. Initially, feeding tray100is raised towards gripping element103. Thereafter articles102are gripped by gripping element103so as to be suspended from gripping element103. At the next stage, articles102are lifted from feeding tray100and driven by system106, on divider bridges104towards conveyor belt partitions101. Subsequently, system106facilitates advancements of articles102suspended from gripping element103in the direction of divider bridges104towards moving conveyor belt partitions101. Gripping element103loaded with articles102moves in synchronization with conveyor belt partitions101, at a speed of the gripping element103along divider bridges104is determined according to the equation:
V1=V2/COS α  (Equation 1),
wherein V1 is the speed of gripping element103relative to divider bridges104, α is an angle between divider bridges104and conveyor belt, whereas V2 is conveyor belt speed, resulting in a relative linear speed of about zero between articles102and conveyor belt, in the direction of advancement of the conveyor belt. The gripping of articles102can be performed by vacuum, magnetic field, physical gripping or any other known means.

Feeding system106preferably comprises a servomechanism drive, electronically scheduled and synchronized with the drive system of the conveyor belt. The drive system of conveyor belt keeps the conveyor advancing continuously. At the final stage articles102are released from gripping element103to spontaneously fall into partitions101. The conveyor belt keeps moving and so do the gripping element103up to a point when articles102are aligned as desired across the width of the conveyor belt. At this point feeding system106has terminated a half of the loading cycle. Thereafter gripping element103return back (not shown) to feeding tray100to complete an entire feeding cycle of system106.

While articles102are in conveyor belt partitions101being transferred forwards, articles102are preferably photographed and programmatically analyzed by digital camera108. The analyzed results determine which article102is to be emitted, cut or sorted, so as to be thereafter automatically bundled and packaged. According to analysis results, articles102are then channeled to different compartments (not shown). Articles102that are to be cut are preferably conveyed to cutting system109.

Reference is now made toFIG. 4A to 6D, showing cutting system109. When partitions101loaded with articles102reach cutting system109, articles102are forced towards sharp knives110. Articles102bend towards knives110due to a synchronized pulse of air pressure emitted by air pressure system nozzles111. The quick encounter of articles102with sharp knives110makes a cut at the meeting point and cut articles102advance to a bundling and packaging area. It is noted that partitions101preferably comprise an aperture configured to facilitate the encounter of articles102with knives110.