GB2608395A

GB2608395A - A sorting system

Info

Publication number: GB2608395A
Application number: GB2109379.4A
Authority: GB
Inventors: John Hyslop David
Original assignee: Hysort Ltd
Current assignee: Hysort Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2023-01-04
Also published as: GB202109379D0

Abstract

An apparatus and method for sorting items includes a controller configured to receive information about an item to be sorted, a track having at least one sort location and a sorter carrier 21, such as a shuttle, configured to move along the track and carry an item to be sorted. The sorter carrier has a discharge mechanism, such as a conveyor belt 22, to discharge the item to be sorted at the sort destination. The item width, length, coefficient of friction and position on the carrier may be sensed by a vision system or barcode reader and each sorter carrier may have speed control allowing different carriers to have different speeds. Each sorter may have a motor and a power source, which may be a hook up or a rechargeable battery.

Description

A SORTING SYSTEM

Description

This specification relates to package sorting. In particular, although not exclusively, this specification relates to an item carrier for use in a package sorting system.

A sorter using independently driven item carriers, either a cross belt or other discharge system, has the ability to move past the sort destination with varying speed. From the carrier's maximum speed to zero at the time of item discharge.

Individual carriers can be moved vertically within the machine by a lift allowing multiple levels of sort destinations to be accessed which reduces the floorspace required for the sort destinations and sorter. The carriers travel along different levels between multiple lifts forming a return path for the carrier to come back to collect additional items from one or more item induct points.

Independently driven carriers are a significant part of the cost of the total sorter solution as they each have a controller, sensors, drive motor and power pickup onboard (and possibly energy storage e.g. battery or capacitor).

Carriers slowing down or stopping, to sort an item, prevent other carriers, on the same level, from overtaking. This reduces the overall throughput rate of the sorter. Adding more carriers increases the capacity of the sorting machine up to the point other bottlenecks are reached i.e. the capacity of lifts or item induct stations.

Additional carriers, however, increase the cost to the sorter. Finding a way to maximise the throughput of the carriers allows the best combination of capital cost and sorter capacity per hour.

Therefore, a mechanism for maximising the throughput of an item sorting machine has been developed. This may employ a set number of independent carriers, and may vary and optimise, for each item to be sorted, the speed of the item carrier and discharge mechanism before and during the discharge of the item. The innovation uses the item attributes, dimensions and position on the carrier to allow the control system to optimise the carrier drive motors. -2 -

In addition, the systems and methods may allow the minimisation of the number of carriers needed to reach the throughput of an item sorting machine, by varying and optimising, for each item to be sorted, the speed of the item carrier and discharge mechanism before and during the discharge of the item. The innovation uses the item attributes, dimensions and position on the carrier to allow the control system to optimise the carrier drive motors.

An aspect of the invention provides a sorting apparatus, the sorting apparatus including a control arrangement configured to receive information about at least one item to be sorted, a track arrangement including at least one sort location, and at least one sorter carrier configured to carry an item to be sorted, the sorter carrier including a drive arrangement, wherein the or each sorter carrier is configured to move along the track arrangement and carry an item to be sorted, and the or each sorter carrier further includes a discharge arrangement configured to discharge the item to be sorted.

Preferably, the information about the or each item to be sorted includes at least the width and length of the item and the position of the item to be sorted on the or each sorter carrier.

Conveniently, the information about the or each item to be sorted is provided by way of a sensor arrangement.

Advantageously, the sensor arrangement includes a camera, vision system, a photocell, and/or a barcode reader.

Preferably, the or each sorter carrier includes a speed control.

Conveniently, the information about the or each item to be sorted is used to determine and control the speed of the carrier and the point of discharge of the or each item to be sorted. This seeks to maximize the throughput of the carrier and sorting system.

Advantageously, the control arrangement is configured to adjust the position of the item on the carrier by way of the discharge arrangement such that it is moved it -3 -towards the side of the or each sorter carrier adjacent to the or each sort location prior to arrival at the or each sort location. This seeks to minimise the distance of travel required to discharge the item into the destination and allowing a higher carrier speed.

Preferably, the information about the or each item to be sorted includes the coefficient of friction of and/or mass of the or each item to be sorted.

Conveniently, the information further includes information about the weight of the item to be sorted.

Advantageously, the discharge arrangement of the or each sorter carrier is a belt arrangement.

Preferably, the belt arrangement is perpendicular to the axis of travel of the sorter carrier.

Conveniently, the belt arrangement is controlled, by the control arrangement, to move the item to be sorted on the or each sorter carrier, toward the relevant sort location, towards the side of the or each sorter carrier.

Advantageously, the apparatus includes an item scanning arrangement configured to read information about the or each item to be sorted.

Preferably, the sorting apparatus includes at least a first sorter carrier and a second sorter carrier.

Conveniently, the first sorter carrier is configured to be propelled at a first speed, and the second sorter carrier is configured to be propelled at a second speed.

Advantageously, the first speed is greater than or less than the second speed.

Preferably, the or each sorter carrier includes a power source and a motor.

Conveniently, the power source is a battery. -4 -

Advantageously, the track arrangement further includes an arrangement configured to charge the battery in the or each sorter carrier.

Another aspect of the invention provides a method of sorting items, the method including the steps of receiving information about at least one item to be sorted; providing at least one sort location, and providing at least one independent sorter carrier, wherein the or each sorter carrier is configured to move between the or each sort location and discharge an item to be sorted, wherein the or each independent sorter carrier may move at a different speed.

A further aspect of the invention provides a sorter carrier, the sorter carrier including a drive arrangement configured to move the sorter carrier, a discharge arrangement configured to move with respect to the sorter carrier, and a power source configured to provide power to the drive arrangement and discharge arrangement.

Preferably, the drive arrangement comprises wheels.

Alternatively, the drive arrangement comprises a belt or belts.

Conveniently, the discharge arrangement is a conveyor belt, the conveyor belt being perpendicular to the axis of travel of the sorter carrier.

Advantageously, the power source is a battery.

Brief Description of the Drawings

An exemplary embodiment of the present invention is illustrated by way of example in the accompanying drawings in which like reference numbers indicate the same or similar elements and in which:-

Figure 1 shows a prior art sorting apparatus;

Figure 2a shows an exemplary sorter carrier within which the present invention may be deployed; -5 -Figure 2b shows an alternative, exemplary sorter carrier within which the present invention may be deployed; Figure 3 shows an exemplary sorting machine using a number of carriers within which the present invention may be deployed; Figure 4 shows a top view of a carrier and item to be sorted as it passes by a group of sort destinations; Figure 5 shows a representation of the locus of travel of an item successfully sorted to a destination by a carrier moving past a row of sort destinations; and Figure 6 shows a representation of the locus of travel of an item when positioned in two places on a carrier.

Referring firstly to Figure 1, there is shown a conventional prior art sorter which is continuously moving in direction 11 perpendicularly to destination chutes 12.

Particularly, Figure 1 shows a conventional sorter with destination chute width greater than the width of the largest item to be sorted to allow for the speed of travel of the carrier as it sorts and moves past the destination simultaneously.

Items are transported on the interconnected carriers 13 and discharged in the direction of the discharge mechanism into the destination chutes. Each chute has a throat wider than the maximum width of items allowed on the sorter so that the item can always be discharged fully within the time between when the trailing edge 14 of the item passes the chute opening position 15 and the time the furthest part of leading edge of the item 16 reaches the other side of the chute opening 17.

For a given maximum item size the speed and capacity of the sorter can be increased by widening the entry to the destination chute (increasing sorter length and cost) or the sorter length can be reduced by slowing down the sorter, reducing throughput. Increasing the speed of discharge helps to reduce the destination width however there are practical limits to this. -6 -

Items 18 and 19 shown in Figure 1 are the same size but have been inducted into different positions on the carriers shown. The time taken for the carrier discharge belt to fully discharge item 18 will be less than the time taken to discharge item 19 as it is further away from the destination chute so the discharge belt has further to travel.

Sorters of the general type as shown in Figure 1 tend to fire the discharge belt at fixed positions. i.e. when the trailing edge of the discharge belt has reached the start of the chute opening and the opposite corner of the discharge belt when looked at in plan view will reach the other side of the carrier before the chute opening is passed this allows items of any size which fit on the carrier to be sorted successfully irrespective of their position on the carrier after being inducted. Some sorters can allow items to straddle multiple carriers (effectively making one larger carrier) but the destination chute openings will be designed to be wide enough to accommodate that mode of operation.

Turning now to Figure 2a, there is shown a sorter carrier 21 with a discharge mechanism 22. In the example shown in Figure 2a, the discharge mechanism is a conveyor belt driven across the carrier perpendicular to the direction of travel of the carrier.

The sorter carrier 21 shown in Figure 2a includes a number of features, each of which will be discussed in turn below.

The sorter carrier 21 may include an apparatus configured to drive the sorter carrier 21 in both the forward and reverse direction. Such an apparatus may be a motor or motors. Additionally, the sorter carrier 21 may include an apparatus configured to drive the discharge belt or discharge mechanism to eject the item into the sort destination. As with the drive apparatus, this may be a motor or motors.

Further, the sorter carrier 21 may include an apparatus configured to control the movement and position, along with item loading and discharge, collision avoidance and communication with the other system controllers of the sorter carrier 21. This control apparatus may be a microprocessor controller or PLC, or suitable alternative. -7 -

The sorter carrier 21 may also include sensors 23 to detect the position of the sorter carrier 21 within a rail structure, along with other parameters such as overhang of product and collision avoidance. In addition to that discussed above, the sorter carrier 21 may include an optional energy store, which may include or comprise a battery or capacitor, and a power pick-up mechanism 24 to power the carrier or to recharge the energy store.

In the case of the sorter carrier 21 shown in Figure 2a, the wheels are fixed, that is to say that they are not capable of 'steering'. Such a sorter carrier 21 may, for example, include one or more steering axes to enable the wheels of the sorter carrier 21 to steer and thus the sorter carrier 21 be able to move along curved rails.

In addition, the sorter carrier 21 may be low profile, that is to say the overall height of the sorter carrier may be minimised, to allow for an item with a large height to be transported on the sorter carrier 21. As can be seen from the rail arrangement of the sorting machine in Figure 3 (discussed below), a first sorter carrier 21 may need to pass under a moving further sorter carrier 21, and if an item with a large height is to be moved within the sorting machine, there is a possibility that the top of the item may foul or catch on the sorter carrier 21 moving thereabove.

It may therefore be advantageous for the overall height of the sorter carrier 21 to be relatively low in order to avoid collisions with other sorter carriers 21 in a sorting machine.

Turning now to Figure 2b, there is shown an alternative carrier with tank tracks instead of wheels. On this version a timing belt 25 (the tank track) is driven between the wheels 26 (drive pulleys) giving a large contact area with the rail. If needed multiple wheels/pulleys can be placed along the length of the track to press the belt down against the rail.

It is envisaged that such an alternative carrier may be used in a sorting machine which may employ a continuous track, that is to say that the track forms a loop or circuit. Such a track may also be sloping, curved, or multi-level. In a situation where the track is multi-level, a curved, inclined, or curved an inclined track may be used to -8 -allow the sorter carrier to move between levels of the machine. Such a track may be used as an alternative to the lift shown in Figure 3 and discussed below.

It is also envisaged that a sorter carrier 21 similar to that shown in Figure 2a may be used in a sorting machine having a continuous track, with the sorter carrier 21 having steering axles on the wheels thereof to allow the sorter carrier 21 to move around curved sections of the machine.

Figure 3 shows multiple carriers 31 in a sorting machine consisting of lifts 32 to move carriers between levels, item induct position 33, and five levels of sort destinations 34 in this example the destinations are totes but they could be chutes, boxes, bags etc. It will now be described how the carriers 31 receive an item to be sorted from the induct station.

The cycle may begin with a carrier 31 at the induct position. An item is placed onto the induction belt 33. A barcode on the item may be scanned, either by the operator using a hand-held scanner or by an automatic scanner whilst the item is moving over the induction belt 33. The controller may use the data from the barcode to look up a database to determine the items intended destination. The database may also give the item attribute data such as weight, dimensions and coefficient of friction. The sorter controller passes the items destination to the carrier controller along with any other data by infrared or radio frequency communication. Bluetooth, WiFi or other RF protocols can be used.

The carrier may then check that the item is not overhanging either end of the carrier belt and that the sensors on the carrier belt are clear. If the item is overhanging a warning appears for the operator to reposition the item. If the item is not overhanging the carrier it is ready to move off towards the lift 31. The carrier controller detects if the lift rail is not in place or if an obstruction (most likely another carrier) is detected by its sensors. When the carrier is clear to move it moves onto the lift. The lift controller has been informed by the main sorter controller ( or the lift shares the main sorter controller) what level to take the carrier and item to. Before the lift moves to the destination level. The vision system connected to the main sorter controller captures a picture of the item on the carrier. Once the image is captured the lift may begin to -9 -move to the destination level. The vision system works out the effective dimensions of the item and the position on the belt.

Once the lift has completed its move to the destination level the induct level is now available to receive another carrier. The main controller calculates the optimum discharge parameters of the item from the carrier and communicates these to the carrier controller. In a variant, the sorter communicates basic information and the carrier determines the optimum discharge speed and the like. Once the first carrier has moved of the lift towards its destination the vision system can capture the image of the item on a second carrier if it has arrived.

The first carrier proceeds towards the sort destination. This may be on the current level of the carrier or on the induct level. If it is the induct level then the carrier will proceed directly to the opposite end of the machine and move over the return lift before proceeding to the sort destination. If the destination is on the current level the carrier may drive at top speed towards the destination. When at an appropriate distance from the destination the carrier begins to decelerate to the discharge speed between top speed and zero m/s. The time at which this deceleration starts is the beginning of the discharge time (DTI At a point along the path the carrier fires the discharge belt, or mechanism, to offload the item into the destination.

The discharge belt may be a conveyor belt driven at 90 degrees to the direction of travel of the carrier and this drives the item from the carrier into the destination tote, chute or other destination.

The point the carrier starts deceleration, the deceleration rate, the point at which the discharge belt starts and stops have all been determined by the controller taking into account the item attribute data and effective dimensions and position of the item on the carrier. The item attribute data and the effective dimensions are discussed in more detail, and with reference to Figure 4, below.

Once the item has been fully discharged the carrier re-accelerates to top speed to continue its journey to the next lift, induct point or other point in the system. The time to discharge ('DT') is complete once the carrier has reached its desired speed for the onward journey. It is to be understood that if the carrier is close to the return lift or -10 -induct point the carrier may not reach top speed before stopping at the next lift or induct point.

The carrier travels over the return lift back to the induct station level. The lift controllers, which may be separate controllers or the main sorter controller ensure only one carrier is on the lift at a time by signalling their status to the carriers so the carriers may have to stop and wait before entering the lifts. The carrier controller uses its sensors to detect any obstacles along the way and avoid collisions or to detect when the lift is not available.

Returning to a discussion of the items being introduced into the system, the item barcode may contain attributes information, or an identification allowing these item attributes, including the destination where the item is to be sorted, to be looked up in a database on a host system which may, for example, be a warehouse management system. Any relevant attribute data is passed to the sorter controller and on to the carrier.

The capacity of the system will now be discussed. The time taken by the carrier to move around the loop and complete a sorting cycle depends upon its speed driving to lifts, destinations and induct points, its acceleration and deceleration profiles at the various positions, the time to discharge the item ('DT) and the time to induct the item. Additionally, the carrier may have to wait for a lift or for another carrier which may be blocking its path.

The system throughput per hour therefore depends upon the average cycle time of a carrier. Adding more carriers to the sorter will increase the throughput until the lifts or other positions become a bottleneck. Once the throughput of the sorter reaches the bottleneck capacity of the lifts or other positions the number of carriers can be minimised by reducing the cycle time of a carrier thereby saving capital cost.

The present invention reduces the carrier cycle time by reducing the average DT time, which as discussed above is the time taken for the carrier to, decelerate, discharge the item and re-accelerate. The DT can be varied depending upon the item size, position on the belt and the coefficient of friction between the belt and item. It does not have to be fixed but can be optimised for each item as the carriers are independent of each other and can overtake on different levels. This is unlike conventional sorters where the carriers are on the same level and connected together.

Accuracy of sorting is of paramount importance to sorter users. Items which miss the destination and land in the neighbouring destination may be sent hundreds of miles across the country only to have to be returned at cost and to the detriment of customer satisfaction.

Turning now to Figure 4, it will be discussed how time and position matter. Figure 4 shows a carrier 41 moving perpendicular to an array of destinations 42 in the direction of travel 43 and carrying an item to be sorted 44. If the carrier is stationary the item will be successfully sorted into the destination by firing the discharge mechanism provided the effective width 45 is less than the width of the destination 46. The effective width should always be slightly smaller than the destination width to allow the item to fit easily into the destination. If the effective width is greater than the destination width the item is highly likely to jam or be missorted.

Figure 5 is diagrammatic representation of the locus of travel of an item successfully sorted to a destination by a carrier moving past a row of sort destinations at a speed low enough to allow a successful sort.

Figure 6 is diagrammatic representation of the locus's of travel of an item when positioned in 2 different places on a carrier showing both successful and unsuccessful sort attempts as the carrier moves past a row of sort destinations; Figure 5 shows an item 51 which is smaller than the item 44 of Figure 4. Figure 5 also shows the locus of travel 52 of the item 51, into the destination when the carrier discharge speed is fixed and there is an acceptable positive speed of the carrier in the direction of travel 43. The larger the effective width 45 of the item 51, compared to the destination width 46, the harder it is for the item to successfully hit the target destination whilst the carrier is moving at this speed.

Figure 6 shows a further scenario, detailing the effect of an item being in a different position on the carrier for a given discharge and carrier direction 63 and speed. The -12 -position of item 61 and its locus of travel into the destination result in a successful sort however, if the item was at the position 62 it would result in a failure if the discharge belt is activated at the same time as when sorting item at position 61. Item 62 would be correctly sorted if the discharge belt was fired earlier. If the carrier were to stop at the destination it would not matter what position the items were in so long as they were on the discharge belt and the discharge belts width and the effective width of the item were less than the width of the destination.

To date sorters on the market use a fixed speed of carrier moving passed destinations or stop at the destination.

This innovation is to use the item attributes of its width, length, coefficient of friction and its position on the carrier to maximise the forward speed of the carrier and timing of the activation of the discharge mechanism to reduce the total time to successfully discharge an item into a destination. The total time to discharge includes the time lost by decelerating from the original carrier speed to the discharge drive speed, the time driving at the new speed (which could be zero), the time to discharge the item and time lost reaccelerating to the desired speed. These actions can be in series or overlapping The attributes of width, length and coefficient of friction could be passed from a host system to the sorter controller or the dimensions and effective dimensions can be measured using photocells and timers, a vision system or other sensors somewhere on the sorter or carrier prior to the destination being reached. The sorter controller then calculates the best carrier speed and discharge point to successfully sort the item into the destination.

Destination attributes (principally width but also coefficient of friction, orientation, existing fill etc) can also be used by the control system.

The fundamental difference between the innovation and traditional sorters (Prior art) is the ability of the innovation to vary the speed the carrier as it passes by the destination for each sorting action. This allows the carrier to take account of the dimensions, position and other attributes of the item to determine the optimal carrier -13 -and discharge speeds thereby minimizing the number of carriers required (reducing cost) or maximising the sorter throughput.

While the invention has been illustrated and described in detail in the drawings and preceding description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. Each feature of the disclosed embodiments may be replaced by altemative features serving the same, equivalent or similar purpose, unless stated otherwise. Therefore, unless stated otherwise, each feature disclosed is one example of a generic series of equivalent or similar features.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope.

Claims

Claims 1. A sorting apparatus, the sorting apparatus including: a control arrangement configured to receive information about at least one item to be sorted; a track arrangement including at least one sort location; and at least one sorter carrier configured to carry an item to be sorted, the sorter carrier including a drive arrangement, wherein the or each sorter carrier is configured to move along the track arrangement and carry an item to be sorted, and the or each sorter carrier further includes a discharge arrangement configured to discharge the item to be sorted.
2. The sorting apparatus of claim 1, wherein the information about the or each item to be sorted includes at least the width and length of the item and the position of the item to be sorted on the or each sorter carrier.
C\I 3. The sorting apparatus of claim 1 or claim 2, wherein the information about the a) or each item to be sorted is provided by way of a sensor arrangement.
4. The sorting apparatus of claim 3, wherein the sensor arrangement includes a camera, vision system, a photocell, and/or a barcode reader.
5. The sorting apparatus of any one of claims 1 to 4, wherein the or each sorter carrier includes a speed control.
6. The sorting apparatus of claim 5, wherein the information about the or each item to be sorted is used to determine and control the speed of the carrier and the point of discharge of the or each item to be sorted.This seeks to maximize the throughput of the carrier and sorting system.
7. The sorting apparatus of any preceding claim, wherein the control arrangement is configured to adjust the position of the item on the carrier by way of the discharge arrangement such that it is moved it towards the side of the or each sorter carrier adjacent to the or each sort location prior to arrival at the or each sort location.This seeks to minimise the distance of travel required to discharge the item into the destination and allowing a higher carrier speed.
8. The sorting apparatus of any preceding claim, wherein the information about the or each item to be sorted includes the coefficient of friction of and/or mass of the or each item to be sorted.
9. The sorting apparatus of any preceding claim, wherein the information further includes information about the weight of the item to be sorted.
10. The sorting apparatus of any preceding claim, wherein the discharge arrangement of the or each sorter carrier is a belt arrangement.
11. The sorting apparatus of claim 10, wherein the belt arrangement is perpendicular to the axis of travel of the sorter carrier.
12. The sorting apparatus of claim 11, wherein the belt arrangement is controlled, by the control arrangement, to move the item to be sorted on the or each sorter carrier, toward the relevant sort location, towards the side of the or each sorter carrier.
13. The sorting apparatus of any preceding claim, further including an item scanning arrangement configured to read information about the or each item to be sorted.
14. The sorting apparatus of any preceding claim, wherein the sorting apparatus includes at least a first sorter carrier and a second sorter carrier.
15. The sorting apparatus of claim 14, wherein the first sorter carrier is configured to be propelled at a first speed, and the second sorter carrier is configured to be propelled at a second speed.
16. The sorting apparatus of claim 15, wherein the first speed is greater than or less than the second speed.
17. The sorting apparatus of any preceding claim, wherein the or each sorter carrier includes a power source and a motor.
18. The sorting apparatus of claim 17, wherein the power source is a battery.
19. The sorting apparatus of claim 18, wherein the track arrangement further includes an arrangement configured to charge the battery in the or each sorter carrier.
20. A method of sorting items, the method including the steps of: receiving information about at least one item to be sorted; providing at least one sort location; and providing at least one independent sorter carrier, wherein the or each sorter carrier is configured to move between the or each sort location and discharge an item to be sorted, wherein the or each independent sorter carrier may move at a different speed.
21. A sorter carrier, the sorter carrier including: a drive arrangement configured to move the sorter carrier; a discharge arrangement configured to move with respect to the sorter carrier; and a power source configured to provide power to the drive arrangement and discharge arrangement.
22. The sorter carrier of claim 21, wherein the drive arrangement comprises wheels.
23. The sorter carrier of claim 21, wherein the drive arrangement comprises a belt or belts.
24. The sorter carrier of any one of claims 21 to 23, wherein the discharge arrangement is a conveyor belt, the conveyor belt being perpendicular to the axis of travel of the sorter carrier.
25. The sorter carrier of any one of claims 21 to 24, wherein the power source is a battery.